[PATCH 00/12] libtracefs dynamic events support

[PATCH 00/12] libtracefs dynamic events support

[Tzvetomir Stoyanov (VMware)]

The libtracefs logic that works with ftrace dynamic events is unified and
capsulated into internal APIs. This change makes the code more consistent
and reusable. Also, adding future libtracefs support for uprobes and
eprobes dynamic events is simplified.
The existing library APIs for kprobes and synthetic events are reimplemented
using the new dynamic events helpers.

Tzvetomir Stoyanov (VMware) (12):
  libtracefs: Add new internal APIs for dynamic events
  libtracefs: Rename tracefs_get_kprobes API
  libtracefs: New kprobes APIs
  libtracefs: Remove redundant kprobes APIs
  libtracefs: Reimplement tracefs_kprobes_get API
  libtracefs: Change tracefs_kprobe_info API
  libtracefs: Reimplement kprobe raw APIs
  libtracefs: Extend kprobes unit test
  libtracefs: Update kprobes man pages
  libtracefs: Rename tracefs_synth_init API
  libtracefs: Use the internal dynamic events API when creating
    synthetic events
  libtracefs: Document tracefs_dynevent_list_free() API

 Documentation/libtracefs-kprobes.txt | 135 ++++---
 Documentation/libtracefs-synth.txt   |  20 +-
 Documentation/libtracefs-synth2.txt  |  10 +-
 Documentation/libtracefs-utils.txt   |   6 +-
 include/tracefs-local.h              |  34 ++
 include/tracefs.h                    |  38 +-
 src/Makefile                         |   1 +
 src/tracefs-dynevents.c              | 463 ++++++++++++++++++++++++
 src/tracefs-hist.c                   | 110 +++---
 src/tracefs-kprobes.c                | 523 +++++++++++++--------------
 src/tracefs-sqlhist.c                |   6 +-
 utest/tracefs-utest.c                | 414 ++++++++++++---------
 12 files changed, 1169 insertions(+), 591 deletions(-)
 create mode 100644 src/tracefs-dynevents.c

-- 
2.31.1

[PATCH 01/12] libtracefs: Add new internal APIs for dynamic events

[Tzvetomir Stoyanov (VMware)]

Ftrace supports dynamic events, created by the user - kprobes, uprobes,
eprobes and synthetic events. There are two interfaces for managing
these events - new common "dynamic_events" file and event specific
"kprobe_events", "uprobe_events", "synthetic_events" files. The
configuration syntax for all dynamic events is almost the same.
To simplify support of dynamic events in thw tracefs library, a new
internal helper layer is implemented. It handles both configuration
interfaces - the common "dynamic_events" file is preferred, if
available. On the old kernels, where this file is missing, the event
specific files are used. The new helper layer can be used to create,
delete and get ftrace dynamic events form any type. Most of the APIs
are internal, not exposed to the library users. Only one API is exposed
publicly:
 tracefs_dynevent_list_free()
This new logic is designed to be used internally within the library,
from the APIs that implement kprobes, uprobes, eprobes and synthetic
events support.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/tracefs-local.h |  34 +++
 include/tracefs.h       |   3 +
 src/Makefile            |   1 +
 src/tracefs-dynevents.c | 463 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 501 insertions(+)
 create mode 100644 src/tracefs-dynevents.c

diff --git a/include/tracefs-local.h b/include/tracefs-local.h
index 684eccf..f15896f 100644
--- a/include/tracefs-local.h
+++ b/include/tracefs-local.h
@@ -94,4 +94,38 @@ int synth_add_start_field(struct tracefs_synth *synth,
 			  const char *start_field,
 			  const char *name,
 			  enum tracefs_hist_key_type type);
+
+/* Internal interface for ftrace dynamic events */
+#define DYNEVENT_ADD_BIT(M, B)		((M) |= (1ULL<<(B)))
+#define DYNEVENT_CHECK_BIT(M, B)	((M)&(1ULL<<(B)))
+
+enum trace_dynevent_type {
+	TRACE_DYNEVENT_KPROBE = 0,
+	TRACE_DYNEVENT_KRETPROBE,
+	TRACE_DYNEVENT_UPROBE,
+	TRACE_DYNEVENT_URETPROBE,
+	TRACE_DYNEVENT_EPROBE,
+	TRACE_DYNEVENT_SYNTH,
+	TRACE_DYNEVENT_MAX,
+};
+
+struct tracefs_dynevent {
+	char *trace_file;
+	char *prefix;
+	char *system;
+	char *event;
+	char *address;
+	char *format;
+	enum trace_dynevent_type type;
+};
+
+struct tracefs_dynevent *
+dynevent_alloc(enum trace_dynevent_type type, const char *system,
+	       const char *event, const char *address, const char *format);
+void dynevent_free(struct tracefs_dynevent *devent);
+int dynevent_create(struct tracefs_dynevent *devent);
+int dynevent_destroy(struct tracefs_dynevent *devent);
+int dynevent_get_all(unsigned long type_mask, const char *system,
+		     struct tracefs_dynevent ***ret_events);
+
 #endif /* _TRACE_FS_LOCAL_H */
diff --git a/include/tracefs.h b/include/tracefs.h
index a2cda30..4020551 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -238,6 +238,9 @@ ssize_t tracefs_trace_pipe_stream(int fd, struct tracefs_instance *instance, int
 ssize_t tracefs_trace_pipe_print(struct tracefs_instance *instance, int flags);
 void tracefs_trace_pipe_stop(struct tracefs_instance *instance);
 
+struct tracefs_dynevent;
+void tracefs_dynevent_list_free(struct tracefs_dynevent ***events);
+
 enum tracefs_kprobe_type {
 	TRACEFS_ALL_KPROBES,
 	TRACEFS_KPROBE,
diff --git a/src/Makefile b/src/Makefile
index 4e38d98..99cd7da 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -11,6 +11,7 @@ OBJS += tracefs-marker.o
 OBJS += tracefs-kprobes.o
 OBJS += tracefs-hist.o
 OBJS += tracefs-filter.o
+OBJS += tracefs-dynevents.o
 
 # Order matters for the the three below
 OBJS += sqlhist-lex.o
diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c
new file mode 100644
index 0000000..68ee95a
--- /dev/null
+++ b/src/tracefs-dynevents.c
@@ -0,0 +1,463 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org>
+ *
+ * Updates:
+ * Copyright (C) 2021, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+
+#include "tracefs.h"
+#include "tracefs-local.h"
+
+#define DYNEVENTS_EVENTS "dynamic_events"
+#define KPROBE_EVENTS "kprobe_events"
+#define UPROBE_EVENTS "uprobe_events"
+#define SYNTH_EVENTS "synthetic_events"
+#define DYNEVENTS_DEFAULT_GROUP "dynamic"
+#define RETPROBE_DEFAUL_PREFIX	"r:"
+
+struct dyn_events_desc;
+static int dyn_generic_parse(struct dyn_events_desc *,
+			     const char *, char *, struct tracefs_dynevent **);
+static int dyn_synth_parse(struct dyn_events_desc *,
+			   const char *, char *, struct tracefs_dynevent **);
+static int dyn_generic_del(struct dyn_events_desc *, struct tracefs_dynevent *);
+static int dyn_synth_del(struct dyn_events_desc *, struct tracefs_dynevent *);
+
+struct dyn_events_desc {
+	enum trace_dynevent_type type;
+	const char *file;
+	const char *prefix;
+	int (*dyn_events_del)(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn);
+	int (*dyn_events_parse)(struct dyn_events_desc *desc, const char *group,
+				char *line, struct tracefs_dynevent **ret_dyn);
+} dynevents[TRACE_DYNEVENT_MAX] = {
+	{TRACE_DYNEVENT_KPROBE, NULL, "p:", dyn_generic_del, dyn_generic_parse},
+	{TRACE_DYNEVENT_KRETPROBE, NULL, "r", dyn_generic_del, dyn_generic_parse},
+	{TRACE_DYNEVENT_UPROBE, NULL, "p:", dyn_generic_del, dyn_generic_parse},
+	{TRACE_DYNEVENT_URETPROBE, NULL, "r", dyn_generic_del, dyn_generic_parse},
+	{TRACE_DYNEVENT_EPROBE, NULL, "e:", dyn_generic_del, dyn_generic_parse},
+	{TRACE_DYNEVENT_SYNTH, NULL, "s:", dyn_synth_del, dyn_synth_parse},
+};
+
+int dyn_generic_del(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn)
+{
+	char *str;
+	int ret;
+
+	if (dyn->system)
+		ret = asprintf(&str, "-:%s/%s", dyn->system, dyn->event);
+	else
+		ret = asprintf(&str, "-:%s", dyn->event);
+
+	if (ret < 0)
+		return -1;
+
+	ret = tracefs_instance_file_append(NULL, desc->file, str);
+	free(str);
+
+	return ret < 0 ? ret : 0;
+}
+
+__hidden void dynevent_free(struct tracefs_dynevent *devent)
+{
+	if (!devent)
+		return;
+	free(devent->system);
+	free(devent->event);
+	free(devent->address);
+	free(devent->format);
+	free(devent->prefix);
+	free(devent->trace_file);
+	free(devent);
+}
+
+static int dyn_generic_parse(struct dyn_events_desc *desc, const char *group,
+			     char *line, struct tracefs_dynevent **ret_dyn)
+{
+	struct tracefs_dynevent *dyn;
+	char *address;
+	char *system;
+	char *format;
+	char *event;
+
+	if (strncmp(line, desc->prefix, strlen(desc->prefix)))
+		return -1;
+
+	system = strchr(line, ':');
+	if (!system)
+		return -1;
+	event = strchr(line, '/');
+	if (!event)
+		return -1;
+	address = strchr(line, ' ');
+	if (!address)
+		return -1;
+	format = strchr(address+1, ' ');
+
+	*address = '\0';
+	*event = '\0';
+
+	/* KPROBEs and UPROBEs share the same prefix, check the format */
+	if (desc->type == TRACE_DYNEVENT_UPROBE || desc->type == TRACE_DYNEVENT_URETPROBE) {
+		if (!strchr(format, '/'))
+			return -1;
+	}
+	if (group && strcmp(group, system+1) != 0)
+		return -1;
+
+	if (!ret_dyn)
+		return 0;
+
+	dyn = calloc(1, sizeof(*dyn));
+	if (!dyn)
+		return -1;
+	dyn->type = desc->type;
+	dyn->trace_file = strdup(desc->file);
+	if (!dyn->trace_file)
+		goto error;
+	dyn->system = strdup(system+1);
+	if (!dyn->system)
+		goto error;
+	*(system+1) = '\0';
+	/* Prefix of KRETPROBE can contain MAXACTIVE integer */
+	dyn->prefix = strdup(line);
+	if (!dyn->prefix)
+		goto error;
+	dyn->event = strdup(event+1);
+	if (!dyn->event)
+		goto error;
+	if (desc->type == TRACE_DYNEVENT_SYNTH) {
+		/* Synthetic events have no address */
+		dyn->format = strdup(address+1);
+		if (!dyn->format)
+			goto error;
+	} else {
+		if (format)
+			*format = '\0';
+		dyn->address = strdup(address+1);
+		if (!dyn->address)
+			goto error;
+		if (format) {
+			dyn->format = strdup(format+1);
+			if (!dyn->format)
+				goto error;
+		}
+	}
+	*ret_dyn = dyn;
+	return 0;
+error:
+	dynevent_free(dyn);
+	return -1;
+}
+
+int dyn_synth_del(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn)
+{
+	char *str;
+	int ret;
+
+	if (strcmp(desc->file, DYNEVENTS_EVENTS))
+		return dyn_generic_del(desc, dyn);
+
+	ret = asprintf(&str, "!%s", dyn->event);
+	if (ret < 0)
+		return -1;
+
+	ret = tracefs_instance_file_append(NULL, desc->file, str);
+	free(str);
+
+	return ret < 0 ? ret : 0;
+}
+
+static int dyn_synth_parse(struct dyn_events_desc *desc, const char *group,
+			   char *line, struct tracefs_dynevent **ret_dyn)
+{
+	struct tracefs_dynevent *dyn;
+	char *format;
+
+	if (strcmp(desc->file, DYNEVENTS_EVENTS))
+		return dyn_generic_parse(desc, group, line, ret_dyn);
+
+	/* synthetic_events file has slightly different syntax */
+	format = strchr(line, ' ');
+	if (!format)
+		return -1;
+	if (!ret_dyn)
+		return 0;
+
+	*format = '\0';
+	dyn = calloc(1, sizeof(*dyn));
+	if (!dyn)
+		return -1;
+	dyn->type = desc->type;
+	dyn->trace_file = strdup(desc->file);
+	if (!dyn->trace_file)
+		goto error;
+
+	dyn->event = strdup(line);
+	if (!dyn->event)
+		goto error;
+	dyn->format = strdup(format+1);
+	if (!dyn->format)
+		goto error;
+
+	*ret_dyn = dyn;
+	return 0;
+error:
+	dynevent_free(dyn);
+	return -1;
+}
+
+static struct dyn_events_desc *get_devent_desc(enum trace_dynevent_type type)
+{
+	static bool init;
+	int i;
+
+	if (init)
+		goto out;
+
+	init = true;
+	/* Use  ftrace dynamic_events, if available */
+	if (tracefs_file_exists(NULL, DYNEVENTS_EVENTS)) {
+		for (i = 0; i < TRACE_DYNEVENT_MAX; i++)
+			dynevents[i].file = DYNEVENTS_EVENTS;
+		goto out;
+	}
+
+	if (tracefs_file_exists(NULL, KPROBE_EVENTS)) {
+		dynevents[TRACE_DYNEVENT_KPROBE].file = KPROBE_EVENTS;
+		dynevents[TRACE_DYNEVENT_KRETPROBE].file = KPROBE_EVENTS;
+	}
+	if (tracefs_file_exists(NULL, UPROBE_EVENTS)) {
+		dynevents[TRACE_DYNEVENT_UPROBE].file = UPROBE_EVENTS;
+		dynevents[TRACE_DYNEVENT_URETPROBE].file = UPROBE_EVENTS;
+	}
+	if (tracefs_file_exists(NULL, SYNTH_EVENTS)) {
+		dynevents[TRACE_DYNEVENT_SYNTH].file = SYNTH_EVENTS;
+		dynevents[TRACE_DYNEVENT_SYNTH].prefix = "";
+	}
+
+out:
+	return &dynevents[type];
+}
+
+__hidden struct tracefs_dynevent *
+dynevent_alloc(enum trace_dynevent_type type, const char *system,
+	       const char *event, const char *address, const char *format)
+{
+	struct tracefs_dynevent *devent;
+	struct dyn_events_desc *desc;
+
+	if (!event) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	desc = get_devent_desc(type);
+	if (!desc || !desc->file) {
+		errno = ENOTSUP;
+		return NULL;
+	}
+
+	devent = calloc(1, sizeof(*devent));
+	if (!devent)
+		return NULL;
+
+	devent->type = type;
+	devent->trace_file = strdup(desc->file);
+	if (!devent->trace_file)
+		goto err;
+	if (!system)
+		system = DYNEVENTS_DEFAULT_GROUP;
+	devent->system = strdup(system);
+	if (!devent->system)
+		goto err;
+	devent->event = strdup(event);
+	if (!devent->event)
+		goto err;
+	if (type == TRACE_DYNEVENT_KRETPROBE || type == TRACE_DYNEVENT_URETPROBE)
+		devent->prefix = strdup(RETPROBE_DEFAUL_PREFIX);
+	else
+		devent->prefix = strdup(desc->prefix);
+
+	if (!devent->prefix)
+		goto err;
+	if (address) {
+		devent->address = strdup(address);
+		if (!devent->address)
+			goto err;
+	}
+	if (format) {
+		devent->format = strdup(format);
+		if (!devent->format)
+			goto err;
+	}
+
+	return devent;
+err:
+	dynevent_free(devent);
+	return NULL;
+}
+
+__hidden int dynevent_create(struct tracefs_dynevent *devent)
+{
+	char *str;
+	int ret;
+
+	if (!devent)
+		return -1;
+	if (devent->system && devent->system[0])
+		ret = asprintf(&str, "%s%s/%s %s %s\n",
+				devent->prefix, devent->system, devent->event,
+				devent->address?devent->address:"",
+				devent->format?devent->format:"");
+	else
+		ret = asprintf(&str, "%s%s %s %s\n",
+				devent->prefix, devent->event,
+				devent->address?devent->address:"",
+				devent->format?devent->format:"");
+	if (ret < 0)
+		return -1;
+	ret = tracefs_instance_file_append(NULL, devent->trace_file, str);
+	free(str);
+
+	return ret < 0 ? ret : 0;
+}
+
+__hidden int dynevent_destroy(struct tracefs_dynevent *devent)
+{
+	struct dyn_events_desc *desc;
+
+	if (!devent)
+		return -1;
+	desc = get_devent_desc(devent->type);
+	if (!desc)
+		return -1;
+	return desc->dyn_events_del(desc, devent);
+}
+
+static int get_all_type(enum trace_dynevent_type type, const char *system,
+			struct tracefs_dynevent ***ret_all)
+{
+	struct dyn_events_desc *desc;
+	struct tracefs_dynevent *devent, **tmp, **all = NULL;
+	char *content;
+	int count = 0;
+	char *line;
+	char *next;
+	int ret;
+
+	desc = get_devent_desc(type);
+	if (!desc)
+		return -1;
+
+	content = tracefs_instance_file_read(NULL, desc->file, NULL);
+	if (!content)
+		return -1;
+	line = content;
+	do {
+		next = strchr(line, '\n');
+		if (next)
+			*next = '\0';
+		ret = desc->dyn_events_parse(desc, system, line, ret_all ? &devent : NULL);
+		if (!ret) {
+			if (ret_all) {
+				tmp = realloc(all, (count+1)*sizeof(struct tracefs_dynevent *));
+				if (!tmp)
+					goto error;
+				all = tmp;
+				all[count] = devent;
+			}
+			count++;
+		}
+		line = next + 1;
+	} while (next);
+
+	free(content);
+	if (ret_all)
+		*ret_all = all;
+	return count;
+
+error:
+	free(content);
+	free(all);
+	return -1;
+}
+
+/**
+ * tracefs_dynevent_list_free - Deletes an array of pointers to dynamic event contexts
+ * @events: An array of pointers to dynamic event contexts. The last element of the array
+ *	    must be a NULL pointer.
+ */
+void tracefs_dynevent_list_free(struct tracefs_dynevent ***events)
+{
+	struct tracefs_dynevent **devent;
+	int i = 0;
+
+	if (!events || !(*events))
+		return;
+
+	devent = *events;
+	while (devent[i])
+		dynevent_free(devent[i++]);
+
+	free(*events);
+}
+
+__hidden int dynevent_get_all(unsigned long type_mask, const char *system,
+			      struct tracefs_dynevent ***ret_events)
+{
+	struct tracefs_dynevent **events, **tmp, **all_events = NULL;
+	int count, all = 0;
+	int i;
+
+	for (i = 0; i < TRACE_DYNEVENT_MAX; i++) {
+		if (!DYNEVENT_CHECK_BIT(type_mask, i))
+			continue;
+		count = get_all_type(i, system, ret_events ? &events : NULL);
+		if (count > 0) {
+			if (ret_events) {
+				tmp = realloc(all_events,
+					     (all + count)*sizeof(struct tracefs_dynevent *));
+				if (!tmp)
+					goto error;
+				all_events = tmp;
+				memcpy(all_events + all, events,
+				       count*sizeof(struct tracefs_dynevent *));
+			}
+			all += count;
+		}
+
+	}
+
+	if (ret_events) {
+		/* Add a NULL pointer at the end */
+		if (all > 0) {
+			tmp = realloc(all_events,
+				     (all + 1)*sizeof(struct tracefs_dynevent *));
+			if (!tmp)
+				goto error;
+			all_events = tmp;
+			all_events[all] = NULL;
+		}
+		*ret_events = all_events;
+	}
+
+	return all;
+
+error:
+	if (all_events) {
+		for (i = 0; i < all; i++)
+			free(all_events[i]);
+		free(all_events);
+	}
+	return -1;
+}
-- 
2.31.1

[PATCH 02/12] libtracefs: Rename tracefs_get_kprobes API

[Tzvetomir Stoyanov (VMware)]

The names of tracefs API should follow the same pattern:
  tracefs_XXX_<action>
Rename tracefs_get_kprobes() to tracefs_kprobes_get() to be
consistent with that pattern.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/libtracefs-kprobes.txt |  8 ++++----
 include/tracefs.h                    |  2 +-
 src/tracefs-kprobes.c                |  6 +++---
 utest/tracefs-utest.c                | 10 +++++-----
 4 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/Documentation/libtracefs-kprobes.txt b/Documentation/libtracefs-kprobes.txt
index c10576e..ca48fa9 100644
--- a/Documentation/libtracefs-kprobes.txt
+++ b/Documentation/libtracefs-kprobes.txt
@@ -3,7 +3,7 @@ libtracefs(3)
 
 NAME
 ----
-tracefs_kprobe_raw, tracefs_kretprobe_raw, tracefs_get_kprobes, tracefs_kprobe_info, tracefs_kprobe_clear_all, tracefs_kprobe_clear_probe - Create, list, and destroy kprobes
+tracefs_kprobe_raw, tracefs_kretprobe_raw, tracefs_kprobes_get, tracefs_kprobe_info, tracefs_kprobe_clear_all, tracefs_kprobe_clear_probe - Create, list, and destroy kprobes
 
 SYNOPSIS
 --------
@@ -13,7 +13,7 @@ SYNOPSIS
 
 int tracefs_kprobe_raw(const char pass:[*]system, const char pass:[*]event, const char pass:[*]addr, const char pass:[*]format);
 int tracefs_kretprobe_raw(const char pass:[*]system, const char pass:[*]event, const char pass:[*]addr, const char pass:[*]format);
-char pass:[*]pass:[*]tracefs_get_kprobes(enum tracefs_kprobe_type type);
+char pass:[*]pass:[*]tracefs_kprobes_get(enum tracefs_kprobe_type type);
 enum tracefs_kprobe_type tracefs_kprobe_info(const char pass:[*]group, const char pass:[*]event,
 					     char pass:[*]pass:[*]type, char pass:[*]pass:[*]addr, char pass:[*]pass:[*]format);
 enum tracefs_kprobe_type tracefs_kprobe_type(const char pass:[*]group, const char pass:[*]event)
@@ -36,7 +36,7 @@ document.
 creates a kretprobe instead of a kprobe. The difference is also described
 in the Linux kernel source in the Documentation/trace/kprobetrace.rst file.
 
-*tracefs_get_kprobes*() returns an array of strings (char pass:[*]) that contain
+*tracefs_kprobes_get*() returns an array of strings (char pass:[*]) that contain
 the registered kprobes and kretprobes depending on the given _type_. If _type_ is
 TRACEFS_ALL_KPROBES, then all kprobes found are returned. If _type_ is
 TRACEFS_KPROBE, then only normal kprobes are returned. If _type_ is
@@ -76,7 +76,7 @@ If a parsing error occurs on *tracefs_kprobe_raw*() or *tracefs_kretprobe_raw*()
 then *tracefs_error_last*(3) may be used to retrieve the error message explaining
 the parsing issue.
 
-*tracefs_get_kprobes*() returns an allocate string list of allocated strings
+*tracefs_kprobes_get*() returns an allocate string list of allocated strings
 on success that must be freed with *tracefs_list_free*(3) and returns
 NULL on error.
 
diff --git a/include/tracefs.h b/include/tracefs.h
index 4020551..0240aef 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -251,7 +251,7 @@ int tracefs_kprobe_raw(const char *system, const char *event,
 		       const char *addr, const char *format);
 int tracefs_kretprobe_raw(const char *system, const char *event,
 			  const char *addr, const char *format);
-char **tracefs_get_kprobes(enum tracefs_kprobe_type type);
+char **tracefs_kprobes_get(enum tracefs_kprobe_type type);
 enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
 					     char **type, char **addr, char **format);
 int tracefs_kprobe_clear_all(bool force);
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 6fdd8f9..d4c5f9e 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -158,7 +158,7 @@ static int parse_kprobe(char *content, char **saveptr,
 }
 
 /**
- * tracefs_get_kprobes - return a list kprobes (by group/event name)
+ * tracefs_kprobes_get - return a list kprobes (by group/event name)
  * @type: The type of kprobes to return.
  *
  * If @type is TRACEFS_ALL_KPROBES all kprobes in the kprobe_events
@@ -174,7 +174,7 @@ static int parse_kprobe(char *content, char **saveptr,
  * only a NULL pointer.
  * On error, NULL is returned.
  */
-char **tracefs_get_kprobes(enum tracefs_kprobe_type type)
+char **tracefs_kprobes_get(enum tracefs_kprobe_type type)
 {
 	char **list = NULL;
 	char *content;
@@ -357,7 +357,7 @@ static int kprobe_clear_probes(const char *group, bool force)
 	int ret;
 	int i;
 
-	kprobe_list = tracefs_get_kprobes(TRACEFS_ALL_KPROBES);
+	kprobe_list = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
 	if (!kprobe_list)
 		return -1;
 
diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index 09bb8f2..7c1a84e 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -583,7 +583,7 @@ static void test_instance_file(void)
 	free(kaddr);
 	free(kformat);
 
-	kprobes = tracefs_get_kprobes(TRACEFS_ALL_KPROBES);
+	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
 	CU_TEST(kprobes != NULL);
 
 	for (i = 0; kprobes[i]; i++) {
@@ -612,7 +612,7 @@ static void test_instance_file(void)
 	tracefs_list_free(kprobes);
 	CU_TEST(i == 3);
 
-	kprobes = tracefs_get_kprobes(TRACEFS_KPROBE);
+	kprobes = tracefs_kprobes_get(TRACEFS_KPROBE);
 	CU_TEST(kprobes != NULL);
 
 	for (i = 0; kprobes[i]; i++) {
@@ -631,7 +631,7 @@ static void test_instance_file(void)
 	tracefs_list_free(kprobes);
 	CU_TEST(i == 2);
 
-	kprobes = tracefs_get_kprobes(TRACEFS_KRETPROBE);
+	kprobes = tracefs_kprobes_get(TRACEFS_KRETPROBE);
 	CU_TEST(kprobes != NULL);
 
 	for (i = 0; kprobes[i]; i++) {
@@ -663,7 +663,7 @@ static void test_instance_file(void)
 	ret = tracefs_kprobe_clear_probe(KPROBE_2_GROUP, NULL, true);
 	CU_TEST(ret == 0);
 
-	kprobes = tracefs_get_kprobes(TRACEFS_ALL_KPROBES);
+	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
 	CU_TEST(kprobes != NULL);
 
 	for (i = 0; kprobes[i]; i++) {
@@ -682,7 +682,7 @@ static void test_instance_file(void)
 	ret = tracefs_kprobe_clear_all(true);
 	CU_TEST(ret == 0);
 
-	kprobes = tracefs_get_kprobes(TRACEFS_ALL_KPROBES);
+	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
 	CU_TEST(kprobes != NULL);
 
 	CU_TEST(kprobes[0] == NULL);
-- 
2.31.1

[PATCH 03/12] libtracefs: New kprobes APIs

[Tzvetomir Stoyanov (VMware)]

In order to be consistent with the other APIs, a new set of kprobe APIs
is introduced:
 tracefs_kprobe_alloc();
 tracefs_kretprobe_alloc();
 tracefs_kprobe_create();
 tracefs_kprobe_destroy();
 tracefs_kprobe_free();
These APIs work with kprobe context, represented by the tracefs_dynevent
structure.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/tracefs.h     |   8 ++
 src/tracefs-kprobes.c | 169 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 177 insertions(+)

diff --git a/include/tracefs.h b/include/tracefs.h
index 0240aef..e7d545c 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -247,6 +247,14 @@ enum tracefs_kprobe_type {
 	TRACEFS_KRETPROBE,
 };
 
+struct tracefs_dynevent *
+tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format);
+struct tracefs_dynevent *
+tracefs_kretprobe_alloc(const char *system, const char *event,
+			const char *addr, const char *format, int max);
+int tracefs_kprobe_create(struct tracefs_dynevent *kprobe);
+int tracefs_kprobe_destroy(struct tracefs_dynevent *kprobe, bool force);
+void tracefs_kprobe_free(struct tracefs_dynevent *kprobe);
 int tracefs_kprobe_raw(const char *system, const char *event,
 		       const char *addr, const char *format);
 int tracefs_kretprobe_raw(const char *system, const char *event,
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index d4c5f9e..80dc327 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -20,6 +20,135 @@
 #define KPROBE_EVENTS "kprobe_events"
 #define KPROBE_DEFAULT_GROUP "kprobes"
 
+static struct tracefs_dynevent *
+kprobe_alloc(enum trace_dynevent_type type, const char *system, const char *event,
+	     const char *addr, const char *format)
+{
+	struct tracefs_dynevent *kp;
+	const char *sys = system;
+	const char *ename = event;
+	char *tmp;
+
+	if (!addr || !format) {
+		errno = EBADMSG;
+		return NULL;
+	}
+	if (!sys)
+		sys = KPROBE_DEFAULT_GROUP;
+
+	if (!event) {
+		ename = strdup(addr);
+		if (!ename)
+			return NULL;
+		tmp = strchr(ename, ':');
+		if (tmp)
+			*tmp = '\0';
+	}
+
+	kp = dynevent_alloc(type, sys, ename, addr, format);
+	if (!event)
+		free((char *)ename);
+	if (!kp)
+		return NULL;
+	return kp;
+}
+
+
+/**
+ * tracefs_kprobe_alloc - Allocate new kprobe context
+ * @system: The system name (NULL for the default kprobes)
+ * @event: The event to create (NULL to use @addr for the event)
+ * @addr: The function and offset (or address) to insert the probe
+ * @format: The format string to define the probe.
+ *
+ * Allocate a kprobe context that will be in the @system group (or kprobes if
+ * @system is NULL). Have the name of @event (or @addr if @event is
+ * NULL). Will be inserted to @addr (function name, with or without
+ * offset, or a address). And the @format will define the format
+ * of the kprobe. See the Linux documentation file under:
+ * Documentation/trace/kprobetrace.rst
+ * The kprobe is not created in the system.
+ *
+ * Return a pointer to a kprobe context on success, or NULL on error.
+ * The returned pointer must be freed with tracefs_kprobe_free()
+ *
+ * errno will be set to EBADMSG if addr or format is NULL.
+ */
+struct tracefs_dynevent *
+tracefs_kprobe_alloc(const char *system, const char *event, const char *addr, const char *format)
+
+{
+	return kprobe_alloc(TRACE_DYNEVENT_KPROBE, system, event, addr, format);
+}
+
+/**
+ * tracefs_kretprobe_alloc - Allocate new kretprobe context
+ * @system: The system name (NULL for the default kprobes)
+ * @event: The event to create (NULL to use @addr for the event)
+ * @addr: The function and offset (or address) to insert the retprobe
+ * @format: The format string to define the retprobe.
+ *
+ * Allocate a kretprobe that will be in the @system group (or kprobes if
+ * @system is NULL). Have the name of @event (or @addr if @event is
+ * NULL). Will be inserted to @addr (function name, with or without
+ * offset, or a address). And the @format will define the raw format
+ * of the kprobe. See the Linux documentation file under:
+ * Documentation/trace/kprobetrace.rst
+ * The kretprobe is not created in the system.
+ *
+ * Return a pointer to a kprobe context on success, or NULL on error.
+ * The returned pointer must be freed with tracefs_kprobe_free()
+ *
+ * errno will be set to EBADMSG if addr or format is NULL.
+ */
+struct tracefs_dynevent *
+tracefs_kretprobe_alloc(const char *system, const char *event,
+			const char *addr, const char *format, int max)
+{
+	struct tracefs_dynevent *kp;
+	int ret;
+
+	kp = kprobe_alloc(TRACE_DYNEVENT_KRETPROBE, system, event, addr, format);
+	if (!kp)
+		return NULL;
+	if (max) {
+		free(kp->prefix);
+		kp->prefix = NULL;
+		ret = asprintf(&kp->prefix, "r%d:", max);
+		if (ret < 0)
+			goto error;
+	}
+
+	return kp;
+error:
+	dynevent_free(kp);
+	return NULL;
+}
+
+/**
+ * tracefs_kprobe_create - Create a kprobe or kretprobe in the system
+ * @kprobe: Pointer to a kprobe context, describing the probe
+ *
+ * Return 0 on success, or -1 on error.
+ */
+int tracefs_kprobe_create(struct tracefs_dynevent *kprobe)
+{
+	return dynevent_create(kprobe);
+}
+
+/**
+ * tracefs_kprobe_free - Free a kprobe context
+ * @kprobe: Pointer to a kprobe context
+ *
+ * The kprobe/kretprobe, described by this context, is not
+ * removed from the system by this API. It only frees the memory.
+ */
+void tracefs_kprobe_free(struct tracefs_dynevent *kprobe)
+{
+	dynevent_free(kprobe);
+}
+
+
 static int insert_kprobe(const char *type, const char *system,
 			 const char *event, const char *addr,
 			 const char *format)
@@ -474,3 +603,43 @@ int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force
 
 	return ret < 0 ? -1 : 0;
 }
+
+/**
+ * tracefs_kprobe_destroy - Remove a kprobe or kretprobe from the system
+ * @kprobe: A kprobe context, describing the kprobe that will be deleted.
+ *	    If NULL, all kprobes and kretprobes in the system will be deleted
+ * @force: Will attempt to disable all kprobe events and clear them
+ *
+ * The kprobe/kretprobe context is not freed by this API.
+ * It only removes the probe from the system.
+ *
+ * Return 0 on success, or -1 on error.
+ */
+int tracefs_kprobe_destroy(struct tracefs_dynevent *kprobe, bool force)
+{
+	char **instance_list;
+	int ret;
+
+	if (!kprobe) {
+		if (tracefs_instance_file_clear(NULL, KPROBE_EVENTS) == 0)
+			return 0;
+		if (!force)
+			return -1;
+		/* Attempt to disable all kprobe events */
+		return kprobe_clear_probes(NULL, force);
+	}
+
+	/*
+	 * Since we know we are disabling a specific event, try
+	 * to disable it first before clearing it.
+	 */
+	if (force) {
+		instance_list = tracefs_instances(NULL);
+		disable_events(kprobe->system, kprobe->event, instance_list);
+		tracefs_list_free(instance_list);
+	}
+
+	ret = dynevent_destroy(kprobe);
+
+	return ret < 0 ? -1 : 0;
+}
-- 
2.31.1

[PATCH 04/12] libtracefs: Remove redundant kprobes APIs

[Tzvetomir Stoyanov (VMware)]

The newly introduced API tracefs_kprobe_destroy() can be used to clear a
specific kprobe or all kprobes from the system. These legacy APIs are
removed as redundant:
 tracefs_kprobe_clear_all();
 tracefs_kprobe_clear_probe();

There is one functionality, missing in the new API - clearing all
kprobes from specific system only. If this is needed,
tracefs_kprobe_destroy() can be extended with that use case.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/tracefs.h     |  2 --
 src/tracefs-kprobes.c | 62 -------------------------------------------
 2 files changed, 64 deletions(-)

diff --git a/include/tracefs.h b/include/tracefs.h
index e7d545c..c7b9179 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -262,8 +262,6 @@ int tracefs_kretprobe_raw(const char *system, const char *event,
 char **tracefs_kprobes_get(enum tracefs_kprobe_type type);
 enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
 					     char **type, char **addr, char **format);
-int tracefs_kprobe_clear_all(bool force);
-int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force);
 
 enum tracefs_hist_key_type {
 	TRACEFS_HIST_KEY_NORMAL = 0,
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 80dc327..1e08b75 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -542,68 +542,6 @@ static int kprobe_clear_probes(const char *group, bool force)
 	return ret;
 }
 
-/**
- * tracefs_kprobe_clear_all - clear kprobe events
- * @force: Will attempt to disable all kprobe events and clear them
- *
- * Will remove all defined kprobe events. If any of them are enabled,
- * and @force is not set, then it will error with -1 and errno to be
- * EBUSY. If @force is set, then it will attempt to disable all the kprobe
- * events in all instances, and try again.
- *
- * Returns zero on success, -1 otherwise.
- */
-int tracefs_kprobe_clear_all(bool force)
-{
-	if (tracefs_instance_file_clear(NULL, KPROBE_EVENTS) == 0)
-		return 0;
-
-	if (!force)
-		return -1;
-
-	/* Attempt to disable all kprobe events */
-	return kprobe_clear_probes(NULL, force);
-}
-
-/**
- * tracefs_kprobe_clear_all - clear kprobe events
- * @system: System to clear (NULL means default)
- * @event: Name of probe to clear in system (NULL for all probes in system)
- * @force: Will attempt to disable all kprobe events and clear them
- *
- * Will remove the kprobes that match the @system and @event. If @system
- * is NULL, then "kprobes" is used and will ignore all other system
- * groups of kprobes. The @event is NULL then all events under the given
- * @system are removed, otherwise only the event that matches.
- *
- * Returns zero on success, -1 otherwise.
- */
-int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force)
-{
-	char **instance_list;
-	int ret;
-
-	if (!system)
-		system = "kprobes";
-
-	if (!event)
-		return kprobe_clear_probes(system, force);
-
-	/*
-	 * Since we know we are disabling a specific event, try
-	 * to disable it first before clearing it.
-	 */
-	if (force) {
-		instance_list = tracefs_instances(NULL);
-		disable_events(system, event, instance_list);
-		tracefs_list_free(instance_list);
-	}
-
-	ret = clear_kprobe(system, event);
-
-	return ret < 0 ? -1 : 0;
-}
-
 /**
  * tracefs_kprobe_destroy - Remove a kprobe or kretprobe from the system
  * @kprobe: A kprobe context, describing the kprobe that will be deleted.
-- 
2.31.1

[PATCH 05/12] libtracefs: Reimplement tracefs_kprobes_get API

[Tzvetomir Stoyanov (VMware)]

In order to unify the code and reuse the internal helpers for dynamic
events helpers, the tracefs_kprobes_get() API is reimplemented using
the new dynamic events APIs.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/tracefs.h     |   2 +-
 src/tracefs-kprobes.c | 127 +++++++++++-------------------------------
 2 files changed, 33 insertions(+), 96 deletions(-)

diff --git a/include/tracefs.h b/include/tracefs.h
index c7b9179..d4ac8fb 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -259,7 +259,7 @@ int tracefs_kprobe_raw(const char *system, const char *event,
 		       const char *addr, const char *format);
 int tracefs_kretprobe_raw(const char *system, const char *event,
 			  const char *addr, const char *format);
-char **tracefs_kprobes_get(enum tracefs_kprobe_type type);
+int tracefs_kprobes_get(enum tracefs_kprobe_type type, struct tracefs_dynevent ***kprobes);
 enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
 					     char **type, char **addr, char **format);
 
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 1e08b75..2e24051 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -287,77 +287,32 @@ static int parse_kprobe(char *content, char **saveptr,
 }
 
 /**
- * tracefs_kprobes_get - return a list kprobes (by group/event name)
+ * tracefs_kprobes_get - return an array of pointers to kprobes
  * @type: The type of kprobes to return.
+ * @kprobes: return, array of pointers to kprobes
  *
- * If @type is TRACEFS_ALL_KPROBES all kprobes in the kprobe_events
- * are returned. Otherwise if it is TRACEFS_KPROBE, then only
+ * If @type is TRACEFS_ALL_KPROBES all kprobes in the system are returned.
+ * Otherwise if it is TRACEFS_KPROBE, then only
  * normal kprobes (p:) are returned, or if type is TRACEFS_KRETPROBE
  * then only kretprobes (r:) are returned.
  *
- * Returns a list of strings that contain the kprobes that exist
- * in the kprobe_events files. The strings returned are in the
- * "group/event" format.
- * The list must be freed with tracefs_list_free().
- * If there are no kprobes, a list is still returned, but it contains
- * only a NULL pointer.
- * On error, NULL is returned.
+ * In case of an error, -1 is returned and @kprobes is not modified.
+ * In case of success, the count of requested kprobes is returned. An array of
+ * pointers to kprobes is allocated and returned in @kprobes. The size of this array
+ * is the returned count + 1, as the last element is a NULL pointer. The array must be
+ * freed with tracefs_dynevent_list_free().
+ * The @kprobes parameter is optional. If NULL is passed, only the count of the kprobes is returned.
  */
-char **tracefs_kprobes_get(enum tracefs_kprobe_type type)
+int tracefs_kprobes_get(enum tracefs_kprobe_type type, struct tracefs_dynevent ***kprobes)
 {
-	char **list = NULL;
-	char *content;
-	char *saveptr;
-	char *event;
-	char *ktype;
-	int ret;
-
-	errno = 0;
-	content = tracefs_instance_file_read(NULL, KPROBE_EVENTS, NULL);
-	if (!content) {
-		if (errno)
-			return NULL;
-		/* content is NULL on empty file, return an empty list */
-		return trace_list_create_empty();
-	}
+	unsigned long mask = 0;
 
-	ret = parse_kprobe(content, &saveptr, &ktype, NULL, &event, NULL, NULL);
-
-	while (!ret) {
-		char **tmp;
-
-		if (type != TRACEFS_ALL_KPROBES) {
-			switch (*ktype) {
-			case 'p':
-				if (type != TRACEFS_KPROBE)
-					goto next;
-				break;
-			case 'r':
-				if (type != TRACEFS_KRETPROBE)
-					goto next;
-				break;
-			default:
-				goto next;
-			}
-		}
-
-		tmp = tracefs_list_add(list, event);
-		if (!tmp)
-			goto fail;
-		list = tmp;
- next:
-		ret = parse_kprobe(NULL, &saveptr, &ktype, NULL, &event, NULL, NULL);
-	}
+	if (type == TRACEFS_KPROBE || type == TRACEFS_ALL_KPROBES)
+		DYNEVENT_ADD_BIT(mask, TRACE_DYNEVENT_KPROBE);
+	if (type == TRACEFS_KRETPROBE || type == TRACEFS_ALL_KPROBES)
+		DYNEVENT_ADD_BIT(mask, TRACE_DYNEVENT_KRETPROBE);
 
-	if (!list)
-		list = trace_list_create_empty();
- out:
-	free(content);
-	return list;
- fail:
-	tracefs_list_free(list);
-	list = NULL;
-	goto out;
+	return dynevent_get_all(mask, NULL, kprobes);
 }
 
 /**
@@ -465,30 +420,17 @@ static void disable_events(const char *system, const char *event,
 	return;
 }
 
-static int clear_kprobe(const char *system, const char *event)
-{
-	/* '-' + ':' + '/' + '\n' + '\0' = 5 bytes */
-	int len = strlen(system) + strlen(event) + 5;
-	char content[len];
-
-	sprintf(content, "-:%s/%s", system, event);
-	return tracefs_instance_file_append(NULL, KPROBE_EVENTS, content);
-}
-
 static int kprobe_clear_probes(const char *group, bool force)
 {
+	struct tracefs_dynevent **kprobes;
 	char **instance_list;
-	char **kprobe_list;
-	char *saveptr;
-	char *system;
-	char *kprobe;
-	char *event;
 	int ret;
 	int i;
 
-	kprobe_list = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
-	if (!kprobe_list)
-		return -1;
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &kprobes);
+	/* No krpobes or error getting them */
+	if (ret <= 0)
+		return ret;
 
 	instance_list = tracefs_instances(NULL);
 	/*
@@ -504,26 +446,21 @@ static int kprobe_clear_probes(const char *group, bool force)
 	 */
 	ret = group ? 0 : -1;
 
-	for (i = 0; kprobe_list[i]; i++) {
-		kprobe = kprobe_list[i];
-
-		system = strtok_r(kprobe, "/", &saveptr);
-		if (!system)
-			goto out;
-
-		event = strtok_r(NULL," ", &saveptr);
-		if (!event)
-			goto out;
+	for (i = 0; kprobes[i]; i++) {
 
 		/* Skip if this does not match a given system */
-		if (group && strcmp(system, group) != 0)
-			continue;
+		if (group) {
+			if (!kprobes[i]->system)
+				continue;
+			if (strcmp(kprobes[i]->system, group) != 0)
+				continue;
+		}
 
 		if (force)
-			disable_events(system, event, instance_list);
+			disable_events(kprobes[i]->system, kprobes[i]->event, instance_list);
 
 		if (group) {
-			ret = clear_kprobe(system, event);
+			ret = dynevent_destroy(kprobes[i]);
 			if (ret < 0)
 				goto out;
 		} else {
@@ -538,7 +475,7 @@ static int kprobe_clear_probes(const char *group, bool force)
 	}
  out:
 	tracefs_list_free(instance_list);
-	tracefs_list_free(kprobe_list);
+	tracefs_dynevent_list_free(&kprobes);
 	return ret;
 }
 
-- 
2.31.1

[PATCH 06/12] libtracefs: Change tracefs_kprobe_info API

[Tzvetomir Stoyanov (VMware)]

In order to make kprobe APIs consistent with the other libtracefs APIs,
the tracefs_kprobe_info() API is reimplemented and changed to work with
the library kprobe context structure.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/tracefs.h     |   5 +-
 src/tracefs-kprobes.c | 175 ++++++++++++++++--------------------------
 2 files changed, 69 insertions(+), 111 deletions(-)

diff --git a/include/tracefs.h b/include/tracefs.h
index d4ac8fb..c65f21f 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -260,8 +260,9 @@ int tracefs_kprobe_raw(const char *system, const char *event,
 int tracefs_kretprobe_raw(const char *system, const char *event,
 			  const char *addr, const char *format);
 int tracefs_kprobes_get(enum tracefs_kprobe_type type, struct tracefs_dynevent ***kprobes);
-enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
-					     char **type, char **addr, char **format);
+enum tracefs_kprobe_type tracefs_kprobe_info(struct tracefs_dynevent *kprobe,
+					     char **system, char **event,
+					     char **prefix, char **addr, char **format);
 
 enum tracefs_hist_key_type {
 	TRACEFS_HIST_KEY_NORMAL = 0,
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 2e24051..083a3a9 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -234,58 +234,6 @@ int tracefs_kretprobe_raw(const char *system, const char *event,
 	return insert_kprobe("r", system, event, addr, format);
 }
 
-/*
- * Helper function to parse kprobes.
- * @content: The content of kprobe_events on the first iteration.
- *           NULL on next iterations.
- * @saveptr: Same as saveptr for strtok_r
- * @type: Where to store the type (before ':')
- * @system: Store the system of the kprobe (NULL to have event contain
- *          both system and event, as in "kprobes/myprobe").
- * @event: Where to store the event.
- * @addr: Where to store the addr (may be NULL to ignore)
- * @format: Where to store the format (may be NULL to ignore)
- */
-static int parse_kprobe(char *content, char **saveptr,
-			char **type, char **system, char **event,
-			char **addr, char **format)
-{
-	char *p;
-
-	p = strtok_r(content, ":", saveptr);
-	if (!p)
-		return 1; /* eof */
-	*type = p;
-
-	if (system) {
-		p = strtok_r(NULL, "/", saveptr);
-		if (!p)
-			return -1;
-		*system = p;
-	}
-
-	p = strtok_r(NULL, " ", saveptr);
-	if (!p)
-		return -1;
-	*event = p;
-
-	if (addr || format) {
-		p = strtok_r(NULL, " ", saveptr);
-		if (!p)
-			return -1;
-		if (addr)
-			*addr = p;
-	}
-
-	p = strtok_r(NULL, "\n", saveptr);
-	if (!p)
-		return -1;
-	if (format)
-		*format = p;
-
-	return 0;
-}
-
 /**
  * tracefs_kprobes_get - return an array of pointers to kprobes
  * @type: The type of kprobes to return.
@@ -316,74 +264,83 @@ int tracefs_kprobes_get(enum tracefs_kprobe_type type, struct tracefs_dynevent *
 }
 
 /**
- * tracefs_kprobe_info - return the type of kprobe specified.
- * @group: The group the kprobe is in (NULL for the default "kprobes")
- * @event: The name of the kprobe to find.
- * @type: String to return kprobe type (before ':') NULL to ignore.
- * @addr: String to return address kprobe is attached to. NULL to ignore.
- * @format: String to return kprobe format. NULL to ignore.
+ * tracefs_kprobe_info - return details of a kprobe
+ * @kprobe: A kprobe context, describing given kprobe.
+ * @group: return, group in which the kprobe is configured
+ * @event: return, name of the kprobe event
+ * @prefix: return, prefix string of the kprobe
+ *	    for kretprobes, the maxactive count is encoded in the prefix
+ * @addr: return, the function and offset (or address) of the kprobe
+ * @format: return, the format string of the kprobe
  *
- * If @type, @addr, or @format is non NULL, then the returned string
- * must be freed with free(). They will also be set to NULL, and
- * even on error, they may contain strings to be freed. If they are
- * not NULL, then they still need to be freed.
- *
- * Returns TRACEFS_ALL_KPROBES if an error occurs or the kprobe is not found,
- *            or the probe is of an unknown type.
- * TRACEFS_KPROBE if the type of kprobe found is a normal kprobe.
- * TRACEFS_KRETPROBE if the type of kprobe found is a kretprobe.
+ * Returns the type of the kprobe, or TRACEFS_ALL_KPROBES in case of an error.
+ * Any of the @group, @event, @prefix, @addr and @format parameters are optional.
+ * If a valid pointer is passed, in case of success - a string is allocated and returned.
+ * These strings must be freed with free().
  */
-enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
-					     char **type, char **addr, char **format)
+enum tracefs_kprobe_type tracefs_kprobe_info(struct tracefs_dynevent *kprobe,
+					     char **system, char **event,
+					     char **prefix, char **addr, char **format)
 {
-	enum tracefs_kprobe_type rtype = TRACEFS_ALL_KPROBES;
-	char *saveptr;
-	char *content;
-	char *system;
-	char *probe;
-	char *ktype;
-	char *kaddr;
-	char *kfmt;
-	int ret;
-
-	if (!group)
-		group = KPROBE_DEFAULT_GROUP;
-
-	if (type)
-		*type = NULL;
+	if (system)
+		*system = NULL;
+	if (event)
+		*event = NULL;
+	if (prefix)
+		*prefix = NULL;
 	if (addr)
 		*addr = NULL;
 	if (format)
 		*format = NULL;
 
-	content = tracefs_instance_file_read(NULL, KPROBE_EVENTS, NULL);
-	if (!content)
-		return rtype;
-
-	ret = parse_kprobe(content, &saveptr, &ktype, &system, &probe,
-			   &kaddr, &kfmt);
-
-	while (!ret) {
-
-		if (!strcmp(system, group) && !strcmp(probe, event)) {
-			if (type)
-				*type = strdup(ktype);
-			if (addr)
-				*addr = strdup(kaddr);
-			if (format)
-				*format = strdup(kfmt);
+	if (!kprobe)
+		return TRACEFS_ALL_KPROBES;
 
-			switch (*ktype) {
-			case 'p': rtype = TRACEFS_KPROBE; break;
-			case 'r': rtype = TRACEFS_KRETPROBE; break;
-			}
-			break;
+	if (system) {
+		if (kprobe->system) {
+			*system = strdup(kprobe->system);
+			if (!(*system))
+				goto error;
 		}
-		ret = parse_kprobe(NULL, &saveptr, &ktype, &system, &probe,
-				   &kaddr, &kfmt);
 	}
-	free(content);
-	return rtype;
+	if (event) {
+		*event = strdup(kprobe->event);
+		if (!(*event))
+			goto error;
+	}
+	if (prefix) {
+		*prefix = strdup(kprobe->prefix);
+		if (!(*prefix))
+			goto error;
+	}
+	if (addr && kprobe->address) {
+		*addr = strdup(kprobe->address);
+		if (!(*addr))
+			goto error;
+	}
+	if (format && kprobe->format) {
+		*format = strdup(kprobe->format);
+		if (!(*format))
+			goto error;
+	}
+
+	if (kprobe->type == TRACE_DYNEVENT_KPROBE)
+		return TRACEFS_KPROBE;
+	if (kprobe->type == TRACE_DYNEVENT_KRETPROBE)
+		return TRACEFS_KRETPROBE;
+
+error:
+	if (system)
+		free(*system);
+	if (event)
+		free(*event);
+	if (prefix)
+		free(*prefix);
+	if (addr)
+		free(*addr);
+	if (format)
+		free(*format);
+	return TRACEFS_ALL_KPROBES;
 }
 
 static void disable_events(const char *system, const char *event,
-- 
2.31.1

[PATCH 07/12] libtracefs: Reimplement kprobe raw APIs

[Tzvetomir Stoyanov (VMware)]

In order to unify the code and use the new dynamic event helpers, these
kprobe APIs are rewritten:
 kracefs_kprobe_raw()
 kracefs_kretprobe_raw()
The definition and logic of the APIs remain the same.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 src/tracefs-kprobes.c | 44 +++++++++++++++++--------------------------
 1 file changed, 17 insertions(+), 27 deletions(-)

diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 083a3a9..84a9903 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -148,38 +148,28 @@ void tracefs_kprobe_free(struct tracefs_dynevent *kprobe)
 	dynevent_free(kprobe);
 }
 
-
-static int insert_kprobe(const char *type, const char *system,
-			 const char *event, const char *addr,
-			 const char *format)
+static int kprobe_raw(enum trace_dynevent_type type, const char *system,
+		      const char *event, const char *addr, const char *format)
 {
-	char *str;
+	static struct tracefs_dynevent *kp;
 	int ret;
 
-	if (!tracefs_file_exists(NULL, KPROBE_EVENTS))
-		return -1;
-
-	errno = EBADMSG;
-	if (!addr || !format)
+	kp = kprobe_alloc(type, system, event, addr, format);
+	if (!kp)
 		return -1;
 
-	if (!event)
-		event = addr;
-
-	if (system)
-		ret = asprintf(&str, "%s:%s/%s %s %s\n",
-			       type, system, event, addr, format);
-	else
-		ret = asprintf(&str, "%s:%s %s %s\n",
-			       type, event, addr, format);
-
-	if (ret < 0)
-		return -1;
+	if (type == TRACE_DYNEVENT_KRETPROBE) {
+		free(kp->prefix);
+		kp->prefix = NULL;
+		ret = asprintf(&kp->prefix, "r:");
+		if (ret < 0)
+			return ret;
+	}
 
-	ret = tracefs_instance_file_append(NULL, KPROBE_EVENTS, str);
-	free(str);
+	ret = dynevent_create(kp);
+	dynevent_free(kp);
 
-	return ret < 0 ? ret : 0;
+	return ret;
 }
 
 /**
@@ -205,7 +195,7 @@ static int insert_kprobe(const char *type, const char *system,
 int tracefs_kprobe_raw(const char *system, const char *event,
 		       const char *addr, const char *format)
 {
-	return insert_kprobe("p", system, event, addr, format);
+	return kprobe_raw(TRACE_DYNEVENT_KPROBE, system, event, addr, format);
 }
 
 /**
@@ -231,7 +221,7 @@ int tracefs_kprobe_raw(const char *system, const char *event,
 int tracefs_kretprobe_raw(const char *system, const char *event,
 			  const char *addr, const char *format)
 {
-	return insert_kprobe("r", system, event, addr, format);
+	return kprobe_raw(TRACE_DYNEVENT_KRETPROBE, system, event, addr, format);
 }
 
 /**
-- 
2.31.1

[PATCH 08/12] libtracefs: Extend kprobes unit test

[Tzvetomir Stoyanov (VMware)]

As there are a lot of changes in the libtracefs kprobes APIs, the unit
test of that functionality should be updated. A new test section is
added, for testing the all kprobes APIs.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 utest/tracefs-utest.c | 414 +++++++++++++++++++++++++-----------------
 1 file changed, 244 insertions(+), 170 deletions(-)

diff --git a/utest/tracefs-utest.c b/utest/tracefs-utest.c
index 7c1a84e..0a17b82 100644
--- a/utest/tracefs-utest.c
+++ b/utest/tracefs-utest.c
@@ -28,22 +28,6 @@
 #define TRACE_ON	"tracing_on"
 #define TRACE_CLOCK	"trace_clock"
 
-#define KPROBE_EVENTS	"kprobe_events"
-
-#define KPROBE_1_NAME	"mkdir"
-#define KPROBE_1_GROUP	"kprobes"
-#define KPROBE_1_ADDR	"do_mkdirat"
-#define KPROBE_1_FMT	"path=+u0($arg2):ustring"
-
-#define KPROBE_2_NAME	"open"
-#define KPROBE_2_GROUP	"myprobe"
-#define KPROBE_2_ADDR	"do_sys_openat2"
-#define KPROBE_2_FMT	"file=+u0($arg2):ustring flags=+0($arg3):x64"
-
-#define KRETPROBE_NAME	"retopen"
-#define KRETPROBE_ADDR	"do_sys_openat2"
-#define KRETPROBE_FMT	"ret=$retval"
-
 #define SQL_1_EVENT	"wakeup_1"
 #define SQL_1_SQL	"select sched_switch.next_pid as woke_pid, sched_waking.common_pid as waking_pid from sched_waking join sched_switch on sched_switch.next_pid = sched_waking.pid"
 
@@ -457,28 +441,264 @@ static void test_instance_file_read(struct tracefs_instance *inst, const char *f
 	free(file);
 }
 
+#define KPROBE_DEFAULT_GROUP "kprobes"
+struct kprobe_test {
+	enum tracefs_kprobe_type type;
+	char *prefix;
+	char *system;
+	char *event;
+	char *address;
+	char *format;
+};
+
+static bool check_kprobes(struct kprobe_test *kprobes, int count,
+			  struct tracefs_dynevent **devents, bool in_system)
+{
+
+	enum tracefs_kprobe_type ktype;
+	char *ename;
+	char *kaddress;
+	char *kevent;
+	char *ksystem;
+	char *kformat;
+	char *kprefix;
+	int found = 0;
+	int ret;
+	int i, j;
+
+	for (i = 0; devents[i]; i++) {
+		ktype = tracefs_kprobe_info(devents[i], &ksystem,
+					   &kevent, &kprefix, &kaddress, &kformat);
+		for (j = 0; j < count; j++) {
+			if (ktype != kprobes[j].type)
+				continue;
+			if (kprobes[j].event)
+				ename = kprobes[j].event;
+			else
+				ename = kprobes[j].address;
+			if (strcmp(ename, kevent))
+				continue;
+			if (kprobes[j].system) {
+				CU_TEST(strcmp(kprobes[j].system, ksystem) == 0);
+			} else {
+				CU_TEST(strcmp(KPROBE_DEFAULT_GROUP, ksystem) == 0);
+			}
+			CU_TEST(strcmp(kprobes[j].address, kaddress) == 0);
+			CU_TEST(strcmp(kprobes[j].format, kformat) == 0);
+			if (kprobes[j].prefix)
+				CU_TEST(strcmp(kprobes[j].prefix, kprefix) == 0);
+			ret = tracefs_event_enable(test_instance, ksystem, kevent);
+			if (in_system) {
+				CU_TEST(ret == 0);
+			} else {
+				CU_TEST(ret != 0);
+			}
+			ret = tracefs_event_disable(test_instance, ksystem, kevent);
+			if (in_system) {
+				CU_TEST(ret == 0);
+			} else {
+				CU_TEST(ret != 0);
+			}
+
+			found++;
+			break;
+		}
+		free(ksystem);
+		free(kevent);
+		free(kprefix);
+		free(kaddress);
+		free(kformat);
+	}
+
+	CU_TEST(found == count);
+	if (found != count)
+		return false;
+
+	return true;
+}
+
+#define KPROBE_COUNT	2
+#define KRETPROBE_COUNT	2
+static void test_kprobes(void)
+{
+	char *tmp;
+
+	struct kprobe_test ktests[KPROBE_COUNT] = {
+		{ TRACEFS_KPROBE, "p:", NULL, "mkdir", "do_mkdirat", "path=+u0($arg2):ustring" },
+		{ TRACEFS_KPROBE, "p:", "ptest", "open", "do_sys_openat2",
+				  "file=+u0($arg2):ustring flags=+0($arg3):x64" },
+	};
+	struct kprobe_test kretests[KRETPROBE_COUNT] = {
+		{ TRACEFS_KRETPROBE, NULL, NULL, "retopen", "do_sys_openat2", "ret=$retval" },
+		{ TRACEFS_KRETPROBE, NULL, NULL, NULL, "do_sys_open", "ret=$retval" },
+	};
+	struct tracefs_dynevent *dkretprobe[KRETPROBE_COUNT + 1];
+	struct tracefs_dynevent *dkprobe[KPROBE_COUNT + 1];
+	struct tracefs_dynevent **devents;
+	int ret;
+	int i;
+
+	/* Invalid parameters */
+	CU_TEST(tracefs_kprobe_alloc("test", NULL, NULL, "test") == NULL);
+	CU_TEST(tracefs_kretprobe_alloc("test", NULL, NULL, "test", 0) == NULL);
+	CU_TEST(tracefs_kprobe_alloc("test", NULL, "test", NULL) == NULL);
+	CU_TEST(tracefs_kretprobe_alloc("test", NULL, "test", NULL, 0) == NULL);
+	CU_TEST(tracefs_kprobe_create(NULL) != 0);
+	CU_TEST(tracefs_kprobe_info(NULL, &tmp, &tmp, &tmp, &tmp, &tmp) == TRACEFS_ALL_KPROBES);
+	CU_TEST(tracefs_kprobe_raw("test", "test", NULL, "test") != 0);
+	CU_TEST(tracefs_kretprobe_raw("test", "test", NULL, "test") != 0);
+	CU_TEST(tracefs_kprobe_raw("test", "test", "test", NULL) != 0);
+	CU_TEST(tracefs_kretprobe_raw("test", "test", "test", NULL) != 0);
+
+	/* kprobes APIs */
+	ret = tracefs_kprobe_destroy(NULL, true);
+	CU_TEST(ret == 0);
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &devents);
+	CU_TEST(ret == 0);
+	CU_TEST(devents == NULL);
+
+	for (i = 0; i < KPROBE_COUNT; i++) {
+		dkprobe[i] = tracefs_kprobe_alloc(ktests[i].system, ktests[i].event,
+						  ktests[i].address, ktests[i].format);
+		CU_TEST(dkprobe[i] != NULL);
+	}
+	dkprobe[i] = NULL;
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &devents);
+	CU_TEST(ret == 0);
+	CU_TEST(devents == NULL);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, dkprobe, false));
+
+	for (i = 0; i < KRETPROBE_COUNT; i++) {
+		dkretprobe[i] = tracefs_kretprobe_alloc(kretests[i].system, kretests[i].event,
+							kretests[i].address, kretests[i].format, 0);
+		CU_TEST(dkretprobe[i] != NULL);
+	}
+	dkretprobe[i] = NULL;
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &devents);
+	CU_TEST(ret == 0);
+	CU_TEST(devents == NULL);
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, dkretprobe, false));
+
+	for (i = 0; i < KPROBE_COUNT; i++) {
+		CU_TEST(tracefs_kprobe_create(dkprobe[i]) == 0);
+	}
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &devents);
+	CU_TEST(ret == KPROBE_COUNT);
+	CU_TEST(devents != NULL);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, dkretprobe, false));
+	tracefs_dynevent_list_free(&devents);
+	devents = NULL;
+
+	for (i = 0; i < KRETPROBE_COUNT; i++) {
+		CU_TEST(tracefs_kprobe_create(dkretprobe[i]) == 0);
+	}
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &devents);
+	CU_TEST(ret == (KPROBE_COUNT + KRETPROBE_COUNT));
+	CU_TEST(devents != NULL);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, devents, true));
+	tracefs_dynevent_list_free(&devents);
+	devents = NULL;
+
+	for (i = 0; i < KRETPROBE_COUNT; i++) {
+		CU_TEST(tracefs_kprobe_destroy(dkretprobe[i], false) == 0);
+	}
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &devents);
+	CU_TEST(ret == KPROBE_COUNT);
+	CU_TEST(devents != NULL);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, dkretprobe, false));
+	tracefs_dynevent_list_free(&devents);
+	devents = NULL;
+
+	for (i = 0; i < KPROBE_COUNT; i++) {
+		CU_TEST(tracefs_kprobe_destroy(dkprobe[i], false) == 0);
+	}
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &devents);
+	CU_TEST(ret == 0);
+	CU_TEST(devents == NULL);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, dkprobe, false));
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, dkretprobe, false));
+	tracefs_dynevent_list_free(&devents);
+	devents = NULL;
+
+	for (i = 0; i < KPROBE_COUNT; i++)
+		tracefs_kprobe_free(dkprobe[i]);
+	for (i = 0; i < KRETPROBE_COUNT; i++)
+		tracefs_kprobe_free(dkretprobe[i]);
+
+	/* kprobes raw APIs */
+	ret = tracefs_kprobe_destroy(NULL, true);
+	CU_TEST(ret == 0);
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &devents);
+	CU_TEST(ret == 0);
+	CU_TEST(devents == NULL);
+
+	for (i = 0; i < KPROBE_COUNT; i++) {
+		ret = tracefs_kprobe_raw(ktests[i].system, ktests[i].event,
+					 ktests[i].address, ktests[i].format);
+		CU_TEST(ret == 0);
+	}
+
+	ret = tracefs_kprobes_get(TRACEFS_KPROBE, &devents);
+	CU_TEST(ret == KPROBE_COUNT);
+	CU_TEST(devents != NULL);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	tracefs_dynevent_list_free(&devents);
+	devents = NULL;
+
+	for (i = 0; i < KRETPROBE_COUNT; i++) {
+		ret = tracefs_kretprobe_raw(kretests[i].system, kretests[i].event,
+					    kretests[i].address, kretests[i].format);
+		CU_TEST(ret == 0);
+	}
+
+	ret = tracefs_kprobes_get(TRACEFS_KPROBE, &devents);
+	CU_TEST(ret == KPROBE_COUNT);
+	CU_TEST(devents != NULL);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	tracefs_dynevent_list_free(&devents);
+	devents = NULL;
+
+	ret = tracefs_kprobes_get(TRACEFS_KRETPROBE, &devents);
+	CU_TEST(ret == KRETPROBE_COUNT);
+	CU_TEST(devents != NULL);
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, devents, true));
+	tracefs_dynevent_list_free(&devents);
+	devents = NULL;
+
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &devents);
+	CU_TEST(ret == (KPROBE_COUNT + KRETPROBE_COUNT));
+	CU_TEST(devents != NULL);
+	CU_TEST(check_kprobes(ktests, KPROBE_COUNT, devents, true));
+	CU_TEST(check_kprobes(kretests, KRETPROBE_COUNT, devents, true));
+	tracefs_dynevent_list_free(&devents);
+	devents = NULL;
+
+	ret = tracefs_kprobe_destroy(NULL, true);
+	CU_TEST(ret == 0);
+	ret = tracefs_kprobes_get(TRACEFS_ALL_KPROBES, &devents);
+	CU_TEST(ret == 0);
+	CU_TEST(devents == NULL);
+}
+
 static void test_instance_file(void)
 {
 	struct tracefs_instance *instance = NULL;
 	struct tracefs_instance *second = NULL;
-	enum tracefs_kprobe_type type;
 	const char *name = get_rand_str();
 	const char *inst_name = NULL;
 	const char *tdir;
 	char *inst_file;
 	char *inst_dir;
 	struct stat st;
-	char **kprobes;
-	char *kformat;
-	char *ktype;
-	char *kaddr;
-	char *fname;
 	char *file1;
 	char *file2;
 	char *tracer;
+	char *fname;
 	int size;
 	int ret;
-	int i;
 
 	tdir  = tracefs_tracing_dir();
 	CU_TEST(tdir != NULL);
@@ -541,153 +761,6 @@ static void test_instance_file(void)
 	free(file1);
 	free(file2);
 
-	ret = tracefs_kprobe_clear_all(true);
-	CU_TEST(ret == 0);
-	ret = tracefs_kprobe_raw(NULL, KPROBE_1_NAME, KPROBE_1_ADDR, KPROBE_1_FMT);
-	CU_TEST(ret == 0);
-	ret = tracefs_kprobe_raw(KPROBE_2_GROUP, KPROBE_2_NAME, KPROBE_2_ADDR,
-				 KPROBE_2_FMT);
-	CU_TEST(ret == 0);
-
-	ret = tracefs_kretprobe_raw(KPROBE_2_GROUP, KRETPROBE_NAME, KRETPROBE_ADDR,
-				 KRETPROBE_FMT);
-	CU_TEST(ret == 0);
-
-	type = tracefs_kprobe_info(KPROBE_1_GROUP, KPROBE_1_NAME, &ktype,
-				   &kaddr, &kformat);
-	CU_TEST(type == TRACEFS_KPROBE);
-	CU_TEST(ktype && *ktype == 'p');
-	CU_TEST(kaddr && !strcmp(kaddr, KPROBE_1_ADDR));
-	CU_TEST(kformat && !strcmp(kformat, KPROBE_1_FMT));
-	free(ktype);
-	free(kaddr);
-	free(kformat);
-
-	type = tracefs_kprobe_info(KPROBE_2_GROUP, KPROBE_2_NAME, &ktype,
-				   &kaddr, &kformat);
-	CU_TEST(type == TRACEFS_KPROBE);
-	CU_TEST(ktype && *ktype == 'p');
-	CU_TEST(kaddr && !strcmp(kaddr, KPROBE_2_ADDR));
-	CU_TEST(kformat && !strcmp(kformat, KPROBE_2_FMT));
-	free(ktype);
-	free(kaddr);
-	free(kformat);
-
-	type = tracefs_kprobe_info(KPROBE_2_GROUP, KRETPROBE_NAME, &ktype,
-				   &kaddr, &kformat);
-	CU_TEST(type == TRACEFS_KRETPROBE);
-	CU_TEST(ktype && *ktype == 'r');
-	CU_TEST(kaddr && !strcmp(kaddr, KRETPROBE_ADDR));
-	CU_TEST(kformat && !strcmp(kformat, KRETPROBE_FMT));
-	free(ktype);
-	free(kaddr);
-	free(kformat);
-
-	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
-	CU_TEST(kprobes != NULL);
-
-	for (i = 0; kprobes[i]; i++) {
-		char *system = strtok(kprobes[i], "/");
-		char *event = strtok(NULL, "");
-		bool found = false;
-		if (!strcmp(system, KPROBE_1_GROUP)) {
-			CU_TEST(!strcmp(event, KPROBE_1_NAME));
-			found = true;
-		} else if (!strcmp(system, KPROBE_2_GROUP)) {
-			switch (tracefs_kprobe_info(system, event, NULL, NULL, NULL)) {
-			case TRACEFS_KPROBE:
-				CU_TEST(!strcmp(event, KPROBE_2_NAME));
-				found = true;
-				break;
-			case TRACEFS_KRETPROBE:
-				CU_TEST(!strcmp(event, KRETPROBE_NAME));
-				found = true;
-				break;
-			default:
-				break;
-			}
-		}
-		CU_TEST(found);
-	}
-	tracefs_list_free(kprobes);
-	CU_TEST(i == 3);
-
-	kprobes = tracefs_kprobes_get(TRACEFS_KPROBE);
-	CU_TEST(kprobes != NULL);
-
-	for (i = 0; kprobes[i]; i++) {
-		char *system = strtok(kprobes[i], "/");
-		char *event = strtok(NULL, "");
-		bool found = false;
-		if (!strcmp(system, KPROBE_1_GROUP)) {
-			CU_TEST(!strcmp(event, KPROBE_1_NAME));
-			found = true;
-		} else if (!strcmp(system, KPROBE_2_GROUP)) {
-			CU_TEST(!strcmp(event, KPROBE_2_NAME));
-			found = true;
-		}
-		CU_TEST(found);
-	}
-	tracefs_list_free(kprobes);
-	CU_TEST(i == 2);
-
-	kprobes = tracefs_kprobes_get(TRACEFS_KRETPROBE);
-	CU_TEST(kprobes != NULL);
-
-	for (i = 0; kprobes[i]; i++) {
-		char *system = strtok(kprobes[i], "/");
-		char *event = strtok(NULL, "");
-		bool found = false;
-		if (!strcmp(system, KPROBE_2_GROUP)) {
-			CU_TEST(!strcmp(event, KRETPROBE_NAME));
-			found = true;
-		}
-		CU_TEST(found);
-	}
-	tracefs_list_free(kprobes);
-	CU_TEST(i == 1);
-
-	ret = tracefs_event_enable(instance, KPROBE_1_GROUP, KPROBE_1_NAME);
-	CU_TEST(ret == 0);
-	ret = tracefs_event_enable(instance, KPROBE_2_GROUP, KPROBE_2_NAME);
-	CU_TEST(ret == 0);
-	ret = tracefs_event_enable(instance, KPROBE_2_GROUP, KRETPROBE_NAME);
-	CU_TEST(ret == 0);
-
-	ret = tracefs_kprobe_clear_all(false);
-	CU_TEST(ret < 0);
-
-	ret = tracefs_kprobe_clear_probe(KPROBE_2_GROUP, NULL, false);
-	CU_TEST(ret < 0);
-
-	ret = tracefs_kprobe_clear_probe(KPROBE_2_GROUP, NULL, true);
-	CU_TEST(ret == 0);
-
-	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
-	CU_TEST(kprobes != NULL);
-
-	for (i = 0; kprobes[i]; i++) {
-		char *system = strtok(kprobes[i], "/");
-		char *event = strtok(NULL, "");
-		bool found = false;
-		if (!strcmp(system, KPROBE_1_GROUP)) {
-			CU_TEST(!strcmp(event, KPROBE_1_NAME));
-			found = true;
-		}
-		CU_TEST(found);
-	}
-	tracefs_list_free(kprobes);
-	CU_TEST(i == 1);
-
-	ret = tracefs_kprobe_clear_all(true);
-	CU_TEST(ret == 0);
-
-	kprobes = tracefs_kprobes_get(TRACEFS_ALL_KPROBES);
-	CU_TEST(kprobes != NULL);
-
-	CU_TEST(kprobes[0] == NULL);
-	tracefs_list_free(kprobes);
-
 	tracefs_put_tracing_file(inst_file);
 	free(fname);
 
@@ -1442,4 +1515,5 @@ void test_tracefs_lib(void)
 		    test_custom_trace_dir);
 	CU_add_test(suite, "ftrace marker",
 		    test_ftrace_marker);
+	CU_add_test(suite, "kprobes", test_kprobes);
 }
-- 
2.31.1

[PATCH 09/12] libtracefs: Update kprobes man pages

[Tzvetomir Stoyanov (VMware)]

As there are a lot of changes in the libtracefs kprobes APIs, the
documentation of library should be updated.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/libtracefs-kprobes.txt | 135 ++++++++++++++++-----------
 1 file changed, 79 insertions(+), 56 deletions(-)

diff --git a/Documentation/libtracefs-kprobes.txt b/Documentation/libtracefs-kprobes.txt
index ca48fa9..c11cd5c 100644
--- a/Documentation/libtracefs-kprobes.txt
+++ b/Documentation/libtracefs-kprobes.txt
@@ -3,7 +3,10 @@ libtracefs(3)
 
 NAME
 ----
-tracefs_kprobe_raw, tracefs_kretprobe_raw, tracefs_kprobes_get, tracefs_kprobe_info, tracefs_kprobe_clear_all, tracefs_kprobe_clear_probe - Create, list, and destroy kprobes
+tracefs_kprobe_alloc, tracefs_kretprobe_alloc, tracefs_kprobe_create,
+tracefs_kprobe_destroy, tracefs_kprobe_free, tracefs_kprobes_get,
+tracefs_kprobe_info, tracefs_kprobe_raw, tracefs_kretprobe_raw - Create, get, and destroy kprobes
+
 
 SYNOPSIS
 --------
@@ -11,18 +14,67 @@ SYNOPSIS
 --
 *#include <tracefs.h>*
 
-int tracefs_kprobe_raw(const char pass:[*]system, const char pass:[*]event, const char pass:[*]addr, const char pass:[*]format);
-int tracefs_kretprobe_raw(const char pass:[*]system, const char pass:[*]event, const char pass:[*]addr, const char pass:[*]format);
-char pass:[*]pass:[*]tracefs_kprobes_get(enum tracefs_kprobe_type type);
-enum tracefs_kprobe_type tracefs_kprobe_info(const char pass:[*]group, const char pass:[*]event,
-					     char pass:[*]pass:[*]type, char pass:[*]pass:[*]addr, char pass:[*]pass:[*]format);
-enum tracefs_kprobe_type tracefs_kprobe_type(const char pass:[*]group, const char pass:[*]event)
-int tracefs_kprobe_clear_all(bool force);
-int tracefs_kprobe_clear_probe(const char pass:[*]system, const char pass:[*]event, bool force);
+struct tracefs_dynevent pass:[*]
+*tracefs_kprobe_alloc*(const char pass:[*]_system_, const char pass:[*]_event_,
+		       const char pass:[*]_addr_, const char pass:[*]_format_);
+struct tracefs_dynevent pass:[*]
+*tracefs_kretprobe_alloc*(const char pass:[*]_system_, const char pass:[*]_event_,
+			  const char pass:[*]_addr_, const char pass:[*]_format_, int _max_);
+void *tracefs_kprobe_free*(struct tracefs_dynevent pass:[*]_kprobe_);
+int *tracefs_kprobe_create*(struct tracefs_dynevent pass:[*]_kprobe_);
+int *tracefs_kprobe_destroy*(struct tracefs_dynevent pass:[*]_kprobe_, bool _force_);
+int *tracefs_kprobes_get*(enum tracefs_kprobe_type _type_,
+			  struct tracefs_dynevent pass:[*]pass:[*]pass:[*]_kprobes_);
+enum tracefs_kprobe_type *tracefs_kprobe_info*(struct tracefs_dynevent pass:[*]_kprobe_,
+					       char pass:[*]pass:[*]_system_, char pass:[*]pass:[*]_event_,
+					       char pass:[*]pass:[*]_prefix_, char pass:[*]pass:[*]_addr_,
+					       char pass:[*]pass:[*]_format_);
+int tracefs_kprobe_raw(const char pass:[*]system, const char pass:[*]event,
+		       const char pass:[*]addr, const char pass:[*]format);
+int tracefs_kretprobe_raw(const char pass:[*]system, const char pass:[*]event,
+			  const char pass:[*]addr, const char pass:[*]format);
 --
 
 DESCRIPTION
 -----------
+*tracefs_kprobe_alloc*() allocates a new kprobe context. The kbrobe is not configured in the system.
+The new kprobe will be in the _system_ group (or kprobes if _system_ is NULL). Have the name of
+_event_ (or _addr_ if _event_ is NULL). Will be inserted to _addr_ (function name, with or without
+offset, or a address). And the _format_ will define the format of the kprobe. See the Linux
+documentation file under: Documentation/trace/kprobetrace.rst
+
+*tracefs_kretprobe_alloc*() is the same as *tracefs_kprobe_alloc*, but allocates context for
+kretprobe. It has one additional parameter, which is optional, _max_ - maxactive count.
+See description of kretprobes in the Documentation/trace/kprobetrace.rst file.
+
+*tracefs_kprobe_free*() frees a kprobe context, allocated with *tracefs_kprobe_alloc*() or
+*tracefs_kretprobe_alloc*(). The kprobe is not removed from the system.
+
+*tracefs_kprobe_create*() creates a kprobe or kretprobe in the system. The probe is described by the
+given _kprobe_ context.
+
+*tracefs_kprobe_destroy*() will try to remove the specified _kprobe_ from the system. If _kprobe_
+is NULL, all kprobes and kretprobes in the system will be removed. If the _force_ flag is set, then
+it will disable the given kprobe events before removing them.
+
+*tracefs_kprobes_get*() returns the count of the registered kprobes and kretprobes in the system,
+depending on the given _type_. If _type_ is TRACEFS_ALL_KPROBES, then all kprobes found are
+counted. If _type_ is TRACEFS_KPROBE, then only normal kprobes are counted. If _type_ is
+TRACEFS_KRETPROBE, then only kretprobes are counted. If the _kprobes_ parameter in not NULL, then
+an array of pointers to kprobe contexts is allocated and passed back via _kprobes_. The size of this
+array is the returned count + 1, as the last element is a NULL pointer. The array must be freed with
+*tracefs_dynevent_list_free*(3).
+
+*tracefs_kprobe_info*() returns the type and information of a given _kprobe_. If any of the
+_system_, _event_, _prefix_, _addr_ or _format_ arguments are not NULL, then strings are allocated
+and returned back via these arguments. The _system_ and _event_ holds the system and the name of the
+kprobe. If _prefix_ is non NULL, then it will hold an allocated string that holds the prefix portion
+of the kprobe in the kprobe_events file (the content up to the ":", including it). Note that for
+kretprobes, the max active count is encoded in the prefix srting. If _addr_ is non NULL, it will
+hold the address or function that the kprobe is attached to. If _format_ is non NULL, it will hold
+the format string of the kprobe. Note, that the content in _group_, _event_, _prefix_, _addr_, and
+_format_ must be freed with free(3) if they are set.
+
 *tracefs_kprobe_raw*() will create a kprobe event. If _system_ is NULL, then
 the default "kprobes" is used for the group (event system). Otherwise if _system_
 is specified then the kprobe will be created under the group by that name. The
@@ -36,55 +88,25 @@ document.
 creates a kretprobe instead of a kprobe. The difference is also described
 in the Linux kernel source in the Documentation/trace/kprobetrace.rst file.
 
-*tracefs_kprobes_get*() returns an array of strings (char pass:[*]) that contain
-the registered kprobes and kretprobes depending on the given _type_. If _type_ is
-TRACEFS_ALL_KPROBES, then all kprobes found are returned. If _type_ is
-TRACEFS_KPROBE, then only normal kprobes are returned. If _type_ is
-TRACEFS_KRETPROBE, then only kretprobes are returned.
-The names are in the "system/event" format.
-That is, one string holds both the kprobe's name as well as the group it is
-defined under. These strings are allocated and may be modified with the
-*strtok*(3) and *strtok_r*(3) functions. The string returned must be freed with
-*tracefs_list_free*(3).
-
-*tracefs_kprobe_info*() returns the type of the given kprobe. If _group_ is
-NULL, then the default "kprobes" is used. If _type_ is non NULL, then it will
-hold an allocated string that holds the type portion of the kprobe in the
-kprobe_events file (the content before the ":"). If _addr_ is non NULL, it will
-hold the address or function that the kprobe is attached to. If _format_ is non
-NULL, it will hold the format string of the kprobe. Note, that the content in
-_type_, _addr_, and _format_ must be freed with free(3) if they are set. Even
-in the case of an error, as they may hold information of what caused the error.
-
-*tracefs_kprobe_clear_all*() will try to remove all kprobes that have been
-registered. If the @force flag is set, it will then disable those kprobe events
-if they are enabled and then try to clear the kprobes.
-
-*tracefs_kprobe_clear_probe*() will try to clear specified kprobes. If _system_
-is NULL, then it will only clear the default kprobes under the "kprobes" group.
-If _event_ is NULL, it will clear all kprobes under the given _system_. If the
-_force_ flag is set, then it will disable the given kprobe events before clearing
-them.
-
 RETURN VALUE
 ------------
 
-*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*(), *tracefs_kprobe_clear_all*(),
-and *tracefs_kprobe_clear_probe*() return 0 on success, or -1 on error.
+*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*(), *tracefs_kprobe_create*(),
+and *tracefs_kprobe_destroy*() return 0 on success, or -1 on error.
 
-If a parsing error occurs on *tracefs_kprobe_raw*() or *tracefs_kretprobe_raw*()
-then *tracefs_error_last*(3) may be used to retrieve the error message explaining
-the parsing issue.
+If a parsing error occurs on *tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*() or
+*tracefs_kprobe_create*() then *tracefs_error_last*(3) may be used to retrieve the error message
+explaining the parsing issue.
 
-*tracefs_kprobes_get*() returns an allocate string list of allocated strings
-on success that must be freed with *tracefs_list_free*(3) and returns
-NULL on error.
+*tracefs_kprobes_get*() returns a count of the requested krpobe types, or -1 in case of an error.
+If the _kprobes_ parameter in not NULL, then an array of pointers to kprobe contexts is allocated
+and passed back via _kprobes_. The size of this array is the returned count + 1, as the last element
+is a NULL pointer. The array must be freed with *tracefs_dynevent_list_free*(3).
 
-*tracefs_kprobe_info*() returns the type of the given kprobe. It returns
-TRACEFS_KPROBE for normal kprobes, TRACEFS_KRETPROBE for kretprobes, and
-on error, or if the kprobe is not found TRACEFS_ALL_KPROBES is returned.
-If _type_, _addr_, or _format_ are non NULL, they will contain allocated
-strings that must be freed by free(3) even in the case of error.
+*tracefs_kprobe_info*() returns the type of the given kprobe. It returns TRACEFS_KPROBE for normal
+kprobes, TRACEFS_KRETPROBE for kretprobes or TRACEFS_ALL_KPROBES on error. If _system_, _event_,
+_prefix_, _addr_, or _format_ are non NULL, they will contain allocated strings that must be freed
+by free(3).
 
 ERRORS
 ------
@@ -96,7 +118,8 @@ The following errors are for all the above calls:
 
 *ENOMEM* Memory allocation error.
 
-*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*() can fail with the following errors:
+*tracefs_kprobe_raw*(), *tracefs_kretprobe_raw*(), *tracefs_kprobe_alloc*(),
+*tracefs_kretprobe_alloc*() and *tracefs_kprobe_create*() can fail with the following errors:
 
 *EBADMSG* Either _addr_ or _format_ are NULL.
 
@@ -217,7 +240,7 @@ int main (int argc, char **argv, char **env)
 		exit(-1);
 	}
 
-	tracefs_kprobe_clear_probe(mykprobe, NULL, true);
+	tracefs_kprobe_destroy(NULL, true);
 
 	kprobe_create("open", "do_sys_openat2",
 		      "file=+0($arg2):ustring flags=+0($arg3):x64 mode=+8($arg3):x64\n");
@@ -247,7 +270,7 @@ int main (int argc, char **argv, char **env)
 	} while (waitpid(pid, NULL, WNOHANG) != pid);
 
 	/* Will disable the events */
-	tracefs_kprobe_clear_probe(mykprobe, NULL, true);
+	tracefs_kprobe_destroy(NULL, true);
 	tracefs_instance_destroy(instance);
 	tep_free(tep);
 
@@ -293,5 +316,5 @@ https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/
 
 COPYING
 -------
-Copyright \(C) 2020 VMware, Inc. Free use of this software is granted under
+Copyright \(C) 2021 VMware, Inc. Free use of this software is granted under
 the terms of the GNU Public License (GPL).
-- 
2.31.1

[PATCH 10/12] libtracefs: Rename tracefs_synth_init API

[Tzvetomir Stoyanov (VMware)]

In order to be consistent with the others library APIs, the
tracefs_synth_init() is renamed to tracefs_synth_alloc().

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/libtracefs-synth.txt  | 20 ++++++++++----------
 Documentation/libtracefs-synth2.txt | 10 +++++-----
 include/tracefs.h                   | 18 +++++++++---------
 src/tracefs-hist.c                  | 22 +++++++++++-----------
 src/tracefs-sqlhist.c               |  6 +++---
 5 files changed, 38 insertions(+), 38 deletions(-)

diff --git a/Documentation/libtracefs-synth.txt b/Documentation/libtracefs-synth.txt
index 77076e1..2fd9019 100644
--- a/Documentation/libtracefs-synth.txt
+++ b/Documentation/libtracefs-synth.txt
@@ -3,7 +3,7 @@ libtracefs(3)
 
 NAME
 ----
-tracefs_synth_init, tracefs_synth_add_match_field, tracefs_synth_add_compare_field, tracefs_synth_add_start_field,
+tracefs_synth_alloc, tracefs_synth_add_match_field, tracefs_synth_add_compare_field, tracefs_synth_add_start_field,
 tracefs_synth_add_end_field, tracefs_synth_append_start_filter, tracefs_synth_append_end_filter, tracefs_synth_free,
 - Creation of a synthetic event descriptor
 
@@ -13,7 +13,7 @@ SYNOPSIS
 --
 *#include <tracefs.h>*
 
-struct tracefs_synth pass:[*]tracefs_synth_init(struct tep_handle pass:[*]tep,
+struct tracefs_synth pass:[*]tracefs_synth_alloc(struct tep_handle pass:[*]tep,
 					 const char pass:[*]name,
 					 const char pass:[*]start_system,
 					 const char pass:[*]start_event,
@@ -69,7 +69,7 @@ as a field for both events to calculate the delta in nanoseconds, or use
 *TRACEFS_TIMESTAMP_USECS" as the compare fields for both events to calculate the
 delta in microseconds. This is used as the example below.
 
-*tracefs_synth_init*() allocates and initializes a synthetic event.
+*tracefs_synth_alloc*() allocates and initializes a synthetic event.
 It does not create the synthetic event, but supplies the minimal information
 to do so. See *tracefs_synth_create*(3) for how to create the synthetic
 event in the system. It requires a _tep_ handler that can be created by
@@ -156,11 +156,11 @@ _field_, _compare_, and _val_ are ignored unless _type_ is equal to
 filters on the ending event.
 
 *tracefs_synth_free*() frees the allocated descriptor returned by
-*tracefs_synth_init*().
+*tracefs_synth_alloc*().
 
 RETURN VALUE
 ------------
-*tracefs_synth_init*() returns an allocated struct tracefs_synth descriptor
+*tracefs_synth_alloc*() returns an allocated struct tracefs_synth descriptor
 on sucess or NULL on error.
 
 All other functions that return an integer returns zero on success or -1
@@ -209,11 +209,11 @@ static void make_event(void)
 	tep = tracefs_local_events(NULL);
 
 	/* Initialize the synthetic event */
-	synth = tracefs_synth_init(tep, "wakeup_lat",
-				   NULL, start_event,
-				   NULL, end_event,
-				   start_field, end_field,
-				   match_name);
+	synth = tracefs_synth_alloc(tep, "wakeup_lat",
+				    NULL, start_event,
+				    NULL, end_event,
+				    start_field, end_field,
+				    match_name);
 
 	/* The tep is no longer needed */
 	tep_free(tep);
diff --git a/Documentation/libtracefs-synth2.txt b/Documentation/libtracefs-synth2.txt
index 4c44253..f734b44 100644
--- a/Documentation/libtracefs-synth2.txt
+++ b/Documentation/libtracefs-synth2.txt
@@ -142,11 +142,11 @@ static void make_event(void)
 	tep = tracefs_local_events(NULL);
 
 	/* Initialize the synthetic event */
-	synth = tracefs_synth_init(tep, "wakeup_lat",
-				   NULL, start_event,
-				   NULL, end_event,
-				   start_field, end_field,
-				   match_name);
+	synth = tracefs_synth_alloc(tep, "wakeup_lat",
+				    NULL, start_event,
+				    NULL, end_event,
+				    start_field, end_field,
+				    match_name);
 
 	/* The tep is no longer needed */
 	tep_free(tep);
diff --git a/include/tracefs.h b/include/tracefs.h
index c65f21f..418725e 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -472,15 +472,15 @@ enum tracefs_synth_handler {
 	TRACEFS_SYNTH_HANDLE_CHANGE,
 };
 
-struct tracefs_synth *tracefs_synth_init(struct tep_handle *tep,
-					 const char *name,
-					 const char *start_system,
-					 const char *start_event,
-					 const char *end_system,
-					 const char *end_event,
-					 const char *start_match_field,
-					 const char *end_match_field,
-					 const char *match_name);
+struct tracefs_synth *tracefs_synth_alloc(struct tep_handle *tep,
+					  const char *name,
+					  const char *start_system,
+					  const char *start_event,
+					  const char *end_system,
+					  const char *end_event,
+					  const char *start_match_field,
+					  const char *end_match_field,
+					  const char *match_name);
 int tracefs_synth_add_match_field(struct tracefs_synth *synth,
 				  const char *start_match_field,
 				  const char *end_match_field,
diff --git a/src/tracefs-hist.c b/src/tracefs-hist.c
index 27bab00..9009dba 100644
--- a/src/tracefs-hist.c
+++ b/src/tracefs-hist.c
@@ -692,7 +692,7 @@ static void action_free(struct action *action)
  * @synth: The tracefs_synth descriptor
  *
  * Frees the resources allocated for a @synth created with
- * tracefs_synth_init(). It does not touch the system. That is,
+ * tracefs_synth_alloc(). It does not touch the system. That is,
  * any synthetic event created, will not be destroyed by this
  * function.
  */
@@ -890,7 +890,7 @@ synth_init_from(struct tep_handle *tep, const char *start_system,
 }
 
 /**
- * tracefs_synth_init - create a new tracefs_synth instance
+ * tracefs_synth_alloc - create a new tracefs_synth instance
  * @tep: The tep handle that holds the events to work on
  * @name: The name of the synthetic event being created
  * @start_system: The name of the system of the start event (can be NULL)
@@ -933,15 +933,15 @@ synth_init_from(struct tep_handle *tep, const char *start_system,
  * event on the system is not created. That needs to be done with
  * tracefs_synth_create().
  */
-struct tracefs_synth *tracefs_synth_init(struct tep_handle *tep,
-					 const char *name,
-					 const char *start_system,
-					 const char *start_event_name,
-					 const char *end_system,
-					 const char *end_event_name,
-					 const char *start_match_field,
-					 const char *end_match_field,
-					 const char *match_name)
+struct tracefs_synth *tracefs_synth_alloc(struct tep_handle *tep,
+					  const char *name,
+					  const char *start_system,
+					  const char *start_event_name,
+					  const char *end_system,
+					  const char *end_event_name,
+					  const char *start_match_field,
+					  const char *end_match_field,
+					  const char *match_name)
 {
 	struct tep_event *end_event;
 	struct tracefs_synth *synth;
diff --git a/src/tracefs-sqlhist.c b/src/tracefs-sqlhist.c
index d77ce86..016f3eb 100644
--- a/src/tracefs-sqlhist.c
+++ b/src/tracefs-sqlhist.c
@@ -1419,9 +1419,9 @@ static struct tracefs_synth *build_synth(struct tep_handle *tep,
 	assign_match(start_system, start_event, match,
 		     &start_match, &end_match);
 
-	synth = tracefs_synth_init(tep, name, start_system,
-				   start_event, end_system, end_event,
-				   start_match, end_match, NULL);
+	synth = tracefs_synth_alloc(tep, name, start_system,
+				    start_event, end_system, end_event,
+				    start_match, end_match, NULL);
 	if (!synth)
 		return synth_init_error(tep, table);
 
-- 
2.31.1

[PATCH 11/12] libtracefs: Use the internal dynamic events API when creating synthetic events

[Tzvetomir Stoyanov (VMware)]

Synthetic events are type of ftrace dynamic events. The tracefs library
has an internal helper APIs to manage dynamic events of all types. In
order the code to be consistent, the creation of synthetic events inside
the library is reimplemented with these new dynamic events APIs.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 src/tracefs-hist.c | 88 +++++++++++++++++-----------------------------
 1 file changed, 33 insertions(+), 55 deletions(-)

diff --git a/src/tracefs-hist.c b/src/tracefs-hist.c
index 9009dba..7ac0023 100644
--- a/src/tracefs-hist.c
+++ b/src/tracefs-hist.c
@@ -661,6 +661,7 @@ struct tracefs_synth {
 	struct tep_event	*end_event;
 	struct action		*actions;
 	struct action		**next_action;
+	struct tracefs_dynevent	*dyn_event;
 	char			*name;
 	char			**synthetic_fields;
 	char			**synthetic_args;
@@ -719,6 +720,7 @@ void tracefs_synth_free(struct tracefs_synth *synth)
 		synth->actions = action->next;
 		action_free(action);
 	}
+	dynevent_free(synth->dyn_event);
 
 	free(synth);
 }
@@ -889,6 +891,28 @@ synth_init_from(struct tep_handle *tep, const char *start_system,
 	return synth;
 }
 
+static int alloc_synthetic_event(struct tracefs_synth *synth)
+{
+	char *synthetic_format;
+	const char *field;
+	int i;
+
+	synthetic_format = strdup("");
+	if (!synthetic_format)
+		return -1;
+
+	for (i = 0; synth->synthetic_fields && synth->synthetic_fields[i]; i++) {
+		field = synth->synthetic_fields[i];
+		synthetic_format = append_string(synthetic_format, " ", field);
+	}
+
+	synth->dyn_event = dynevent_alloc(TRACE_DYNEVENT_SYNTH, NULL,
+					  synth->name, NULL, synthetic_format);
+	free(synthetic_format);
+
+	return synth->dyn_event ? 0 : -1;
+}
+
 /**
  * tracefs_synth_alloc - create a new tracefs_synth instance
  * @tep: The tep handle that holds the events to work on
@@ -1609,38 +1633,6 @@ int tracefs_synth_save(struct tracefs_synth *synth,
 	return 0;
 }
 
-static char *create_synthetic_event(struct tracefs_synth *synth)
-{
-	char *synthetic_event;
-	const char *field;
-	int i;
-
-	synthetic_event = strdup(synth->name);
-	if (!synthetic_event)
-		return NULL;
-
-	for (i = 0; synth->synthetic_fields && synth->synthetic_fields[i]; i++) {
-		field = synth->synthetic_fields[i];
-		synthetic_event = append_string(synthetic_event, " ", field);
-	}
-
-	return synthetic_event;
-}
-
-static int remove_synthetic(const char *synthetic)
-{
-	char *str;
-	int ret;
-
-	ret = asprintf(&str, "!%s", synthetic);
-	if (ret < 0)
-		return -1;
-
-	ret = tracefs_instance_file_append(NULL, "synthetic_events", str);
-	free(str);
-	return ret < 0 ? -1 : 0;
-}
-
 static int remove_hist(struct tracefs_instance *instance,
 		       struct tep_event *event, const char *hist)
 {
@@ -1919,7 +1911,6 @@ tracefs_synth_get_start_hist(struct tracefs_synth *synth)
 int tracefs_synth_create(struct tracefs_instance *instance,
 			 struct tracefs_synth *synth)
 {
-	char *synthetic_event;
 	char *start_hist = NULL;
 	char *end_hist = NULL;
 	int ret;
@@ -1937,14 +1928,10 @@ int tracefs_synth_create(struct tracefs_instance *instance,
 	if (verify_state(synth) < 0)
 		return -1;
 
-	synthetic_event = create_synthetic_event(synth);
-	if (!synthetic_event)
+	if (!synth->dyn_event && alloc_synthetic_event(synth))
+		return -1;
+	if (!dynevent_create(synth->dyn_event))
 		return -1;
-
-	ret = tracefs_instance_file_append(NULL, "synthetic_events",
-					   synthetic_event);
-	if (ret < 0)
-		goto free_synthetic;
 
 	start_hist = create_hist(synth->start_keys, synth->start_vars);
 	start_hist = append_filter(start_hist, synth->start_filter,
@@ -1980,9 +1967,7 @@ int tracefs_synth_create(struct tracefs_instance *instance,
  remove_synthetic:
 	free(end_hist);
 	free(start_hist);
-	remove_synthetic(synthetic_event);
- free_synthetic:
-	free(synthetic_event);
+	dynevent_destroy(synth->dyn_event);
 	return -1;
 }
 
@@ -2007,7 +1992,6 @@ int tracefs_synth_create(struct tracefs_instance *instance,
 int tracefs_synth_destroy(struct tracefs_instance *instance,
 			  struct tracefs_synth *synth)
 {
-	char *synthetic_event;
 	char *hist;
 	int ret;
 
@@ -2041,11 +2025,7 @@ int tracefs_synth_destroy(struct tracefs_instance *instance,
 	ret = remove_hist(instance, synth->start_event, hist);
 	free(hist);
 
-	synthetic_event = create_synthetic_event(synth);
-	if (!synthetic_event)
-		return -1;
-
-	ret = remove_synthetic(synthetic_event);
+	ret = dynevent_destroy(synth->dyn_event);
 
 	return ret ? -1 : 0;
 }
@@ -2067,7 +2047,6 @@ int tracefs_synth_show(struct trace_seq *seq,
 		       struct tracefs_instance *instance,
 		       struct tracefs_synth *synth)
 {
-	char *synthetic_event = NULL;
 	char *hist = NULL;
 	char *path;
 	int ret = -1;
@@ -2082,16 +2061,16 @@ int tracefs_synth_show(struct trace_seq *seq,
 		return -1;
 	}
 
-	synthetic_event = create_synthetic_event(synth);
-	if (!synthetic_event)
+	if (!synth->dyn_event && alloc_synthetic_event(synth))
 		return -1;
 
 	path = trace_find_tracing_dir();
 	if (!path)
 		goto out_free;
 
-	trace_seq_printf(seq, "echo '%s' > %s/synthetic_events\n",
-			 synthetic_event, path);
+	trace_seq_printf(seq, "echo '%s%s %s' > %s/%s\n",
+			 synth->dyn_event->prefix, synth->dyn_event->event,
+			 synth->dyn_event->format, path, synth->dyn_event->trace_file);
 
 	tracefs_put_tracing_file(path);
 	path = tracefs_instance_get_dir(instance);
@@ -2118,7 +2097,6 @@ int tracefs_synth_show(struct trace_seq *seq,
 
 	ret = 0;
  out_free:
-	free(synthetic_event);
 	free(hist);
 	tracefs_put_tracing_file(path);
 	return ret;
-- 
2.31.1

[PATCH 12/12] libtracefs: Document tracefs_dynevent_list_free() API

[Tzvetomir Stoyanov (VMware)]

The newly added tracefs_dynevent_list_free() should be documented in the
library man pages.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 Documentation/libtracefs-utils.txt | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Documentation/libtracefs-utils.txt b/Documentation/libtracefs-utils.txt
index 41544ab..2908d41 100644
--- a/Documentation/libtracefs-utils.txt
+++ b/Documentation/libtracefs-utils.txt
@@ -3,7 +3,7 @@ libtracefs(3)
 
 NAME
 ----
-tracefs_tracers, tracefs_get_clock, tracefs_list_free -
+tracefs_tracers, tracefs_get_clock, tracefs_list_free, tracefs_dynevent_list_free -
 Helper functions for working with trace file system.
 
 SYNOPSIS
@@ -15,6 +15,7 @@ SYNOPSIS
 char pass:[*]pass:[*]*tracefs_tracers*(const char pass:[*]_tracing_dir_);
 char pass:[*]*tracefs_get_clock*(struct tracefs_instance pass:[*]_instance_);
 void *tracefs_list_free*(char pass:[*]pass:[*]_list_);
+void *tracefs_dynevent_list_free*(struct tracefs_dynevent pass:[*]pass:[*]pass:[*]events);
 --
 
 DESCRIPTION
@@ -36,6 +37,9 @@ The _tracefs_list_free()_ function frees an array of strings, returned by
 _tracefs_event_systems()_, _tracefs_system_events()_ and _tracefs_tracers()_
 APIs.
 
+The _tracefs_dynevent_list_free()_ functions frees an array of pointers to dynamic event contexts,
+returned by_tracefs_kprobes_get()_ API.
+
 RETURN VALUE
 ------------
 The _tracefs_tracers()_ returns array of strings. The last element in that
-- 
2.31.1

Re: [PATCH 01/12] libtracefs: Add new internal APIs for dynamic events

[Steven Rostedt]

On Thu, 28 Oct 2021 15:08:56 +0300
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> Ftrace supports dynamic events, created by the user - kprobes, uprobes,
> eprobes and synthetic events. There are two interfaces for managing
> these events - new common "dynamic_events" file and event specific
> "kprobe_events", "uprobe_events", "synthetic_events" files. The
> configuration syntax for all dynamic events is almost the same.
> To simplify support of dynamic events in thw tracefs library, a new
> internal helper layer is implemented. It handles both configuration
> interfaces - the common "dynamic_events" file is preferred, if
> available. On the old kernels, where this file is missing, the event
> specific files are used. The new helper layer can be used to create,
> delete and get ftrace dynamic events form any type. Most of the APIs
> are internal, not exposed to the library users. Only one API is exposed
> publicly:
>  tracefs_dynevent_list_free()
> This new logic is designed to be used internally within the library,
> from the APIs that implement kprobes, uprobes, eprobes and synthetic
> events support.
> 
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
> ---
>  include/tracefs-local.h |  34 +++
>  include/tracefs.h       |   3 +
>  src/Makefile            |   1 +
>  src/tracefs-dynevents.c | 463 ++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 501 insertions(+)
>  create mode 100644 src/tracefs-dynevents.c
> 
> diff --git a/include/tracefs-local.h b/include/tracefs-local.h
> index 684eccf..f15896f 100644
> --- a/include/tracefs-local.h
> +++ b/include/tracefs-local.h
> @@ -94,4 +94,38 @@ int synth_add_start_field(struct tracefs_synth *synth,
>  			  const char *start_field,
>  			  const char *name,
>  			  enum tracefs_hist_key_type type);
> +
> +/* Internal interface for ftrace dynamic events */
> +#define DYNEVENT_ADD_BIT(M, B)		((M) |= (1ULL<<(B)))
> +#define DYNEVENT_CHECK_BIT(M, B)	((M)&(1ULL<<(B)))

The above macros are generic enough that they don't need DYNEVENT in the
name. Just call them:

#define SET_BIT(M, B)		do { (M) |= (1ULL << (B)); } while (0)
#define TEST_BIT(M, B)		((M) & (1ULL << (B)))

And might as well add for completeness:

#define CLEAR_BIT(M,B)		do { (M) &= (1ULL << (B)); } while (0)

It is common to use the terminology of "set,clear,test" for bitmasks. Also,
it is best to add the "do { } while (0)" notation for code, as that helps
with some side effects macros can have.


> +
> +enum trace_dynevent_type {
> +	TRACE_DYNEVENT_KPROBE = 0,

No real need for the "= 0" but I'm OK if you want to leave it in. That's
because the C standard states that the first enum is zero.

> +	TRACE_DYNEVENT_KRETPROBE,
> +	TRACE_DYNEVENT_UPROBE,
> +	TRACE_DYNEVENT_URETPROBE,
> +	TRACE_DYNEVENT_EPROBE,
> +	TRACE_DYNEVENT_SYNTH,
> +	TRACE_DYNEVENT_MAX,
> +};
> +
> +struct tracefs_dynevent {
> +	char *trace_file;
> +	char *prefix;
> +	char *system;
> +	char *event;
> +	char *address;
> +	char *format;
> +	enum trace_dynevent_type type;
> +};
> +
> +struct tracefs_dynevent *
> +dynevent_alloc(enum trace_dynevent_type type, const char *system,
> +	       const char *event, const char *address, const char *format);
> +void dynevent_free(struct tracefs_dynevent *devent);
> +int dynevent_create(struct tracefs_dynevent *devent);
> +int dynevent_destroy(struct tracefs_dynevent *devent);
> +int dynevent_get_all(unsigned long type_mask, const char *system,
> +		     struct tracefs_dynevent ***ret_events);

I usually prefer to have a list returned, and NULL on error, instead of
passing it in by reference. The "***" gets a bit out of hand.


> +
>  #endif /* _TRACE_FS_LOCAL_H */
> diff --git a/include/tracefs.h b/include/tracefs.h
> index a2cda30..4020551 100644
> --- a/include/tracefs.h
> +++ b/include/tracefs.h
> @@ -238,6 +238,9 @@ ssize_t tracefs_trace_pipe_stream(int fd, struct tracefs_instance *instance, int
>  ssize_t tracefs_trace_pipe_print(struct tracefs_instance *instance, int flags);
>  void tracefs_trace_pipe_stop(struct tracefs_instance *instance);
>  
> +struct tracefs_dynevent;
> +void tracefs_dynevent_list_free(struct tracefs_dynevent ***events);

Why are you passing in the address?

Just use: struct tracefs_dynevent **events

If it is to be consistent with the get_all() then that's another reason to
not pass it in as a parameter. That would be like:

 int malloc(int size, void **m);

and

  void free(void **m)


> +
>  enum tracefs_kprobe_type {
>  	TRACEFS_ALL_KPROBES,
>  	TRACEFS_KPROBE,
> diff --git a/src/Makefile b/src/Makefile
> index 4e38d98..99cd7da 100644
> --- a/src/Makefile
> +++ b/src/Makefile
> @@ -11,6 +11,7 @@ OBJS += tracefs-marker.o
>  OBJS += tracefs-kprobes.o
>  OBJS += tracefs-hist.o
>  OBJS += tracefs-filter.o
> +OBJS += tracefs-dynevents.o
>  
>  # Order matters for the the three below
>  OBJS += sqlhist-lex.o
> diff --git a/src/tracefs-dynevents.c b/src/tracefs-dynevents.c
> new file mode 100644
> index 0000000..68ee95a
> --- /dev/null
> +++ b/src/tracefs-dynevents.c
> @@ -0,0 +1,463 @@
> +// SPDX-License-Identifier: LGPL-2.1
> +/*
> + * Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org>
> + *
> + * Updates:
> + * Copyright (C) 2021, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
> + *
> + */
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <dirent.h>
> +#include <unistd.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <limits.h>
> +
> +#include "tracefs.h"
> +#include "tracefs-local.h"
> +
> +#define DYNEVENTS_EVENTS "dynamic_events"
> +#define KPROBE_EVENTS "kprobe_events"
> +#define UPROBE_EVENTS "uprobe_events"
> +#define SYNTH_EVENTS "synthetic_events"
> +#define DYNEVENTS_DEFAULT_GROUP "dynamic"
> +#define RETPROBE_DEFAUL_PREFIX	"r:"
> +
> +struct dyn_events_desc;
> +static int dyn_generic_parse(struct dyn_events_desc *,
> +			     const char *, char *, struct tracefs_dynevent **);
> +static int dyn_synth_parse(struct dyn_events_desc *,
> +			   const char *, char *, struct tracefs_dynevent **);
> +static int dyn_generic_del(struct dyn_events_desc *, struct tracefs_dynevent *);
> +static int dyn_synth_del(struct dyn_events_desc *, struct tracefs_dynevent *);
> +
> +struct dyn_events_desc {
> +	enum trace_dynevent_type type;
> +	const char *file;
> +	const char *prefix;
> +	int (*dyn_events_del)(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn);
> +	int (*dyn_events_parse)(struct dyn_events_desc *desc, const char *group,
> +				char *line, struct tracefs_dynevent **ret_dyn);
> +} dynevents[TRACE_DYNEVENT_MAX] = {

You don't need the TRACE_DYNEVENT_MAX. Just have:

 } dynevents[] = {

And the compiler will fill in the rest.

We could add somewhere in the code:

	BUILD_BUG_ON(ARRAY_SIZE(dynevents) != TRACE_DYNEVENT_MAX);

to make sure all are accounted for.

> +	{TRACE_DYNEVENT_KPROBE, NULL, "p:", dyn_generic_del, dyn_generic_parse},
> +	{TRACE_DYNEVENT_KRETPROBE, NULL, "r", dyn_generic_del, dyn_generic_parse},
> +	{TRACE_DYNEVENT_UPROBE, NULL, "p:", dyn_generic_del, dyn_generic_parse},
> +	{TRACE_DYNEVENT_URETPROBE, NULL, "r", dyn_generic_del, dyn_generic_parse},
> +	{TRACE_DYNEVENT_EPROBE, NULL, "e:", dyn_generic_del, dyn_generic_parse},
> +	{TRACE_DYNEVENT_SYNTH, NULL, "s:", dyn_synth_del, dyn_synth_parse},
> +};
> +
> +int dyn_generic_del(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn)
> +{
> +	char *str;
> +	int ret;
> +
> +	if (dyn->system)
> +		ret = asprintf(&str, "-:%s/%s", dyn->system, dyn->event);
> +	else
> +		ret = asprintf(&str, "-:%s", dyn->event);
> +
> +	if (ret < 0)
> +		return -1;
> +
> +	ret = tracefs_instance_file_append(NULL, desc->file, str);
> +	free(str);
> +
> +	return ret < 0 ? ret : 0;
> +}
> +
> +__hidden void dynevent_free(struct tracefs_dynevent *devent)
> +{
> +	if (!devent)
> +		return;
> +	free(devent->system);
> +	free(devent->event);
> +	free(devent->address);
> +	free(devent->format);
> +	free(devent->prefix);
> +	free(devent->trace_file);
> +	free(devent);
> +}
> +
> +static int dyn_generic_parse(struct dyn_events_desc *desc, const char *group,
> +			     char *line, struct tracefs_dynevent **ret_dyn)

Again, I prefer to have the pointer returned, and not assigned as a
parameter. All this returns is 0 on success or -1 on failure. That doesn't
give us anything more than having ret_dyn allocated or not. (return NULL or
non-NULL).

> +{
> +	struct tracefs_dynevent *dyn;
> +	char *address;
> +	char *system;
> +	char *format;
> +	char *event;
> +
> +	if (strncmp(line, desc->prefix, strlen(desc->prefix)))
> +		return -1;
> +
> +	system = strchr(line, ':');
> +	if (!system)
> +		return -1;
> +	event = strchr(line, '/');
> +	if (!event)
> +		return -1;
> +	address = strchr(line, ' ');
> +	if (!address)
> +		return -1;
> +	format = strchr(address+1, ' ');
> +
> +	*address = '\0';
> +	*event = '\0';


The above should use strtok_r.

	char *probe;
	char *sav;

	probe = strtok_r(line, ":", &sav);
	system = strtok_r(NULL, "/", &sav);
	event = strtok_r(NULL, " ", &sav);
	address = strtok_r(NULL, " ", &sav);
	format = strtok_r(NULL, "\n", &sav);




> +
> +	/* KPROBEs and UPROBEs share the same prefix, check the format */
> +	if (desc->type == TRACE_DYNEVENT_UPROBE || desc->type == TRACE_DYNEVENT_URETPROBE) {
> +		if (!strchr(format, '/'))
> +			return -1;
> +	}
> +	if (group && strcmp(group, system+1) != 0)

No need for +1.

> +		return -1;
> +
> +	if (!ret_dyn)
> +		return 0;
> +
> +	dyn = calloc(1, sizeof(*dyn));
> +	if (!dyn)
> +		return -1;

add space here. All error checks should have a blank line after them.

> +	dyn->type = desc->type;
> +	dyn->trace_file = strdup(desc->file);
> +	if (!dyn->trace_file)
> +		goto error;

> +	dyn->system = strdup(system+1);
> +	if (!dyn->system)
> +		goto error;

> +	*(system+1) = '\0';
> +	/* Prefix of KRETPROBE can contain MAXACTIVE integer */
> +	dyn->prefix = strdup(line);
> +	if (!dyn->prefix)
> +		goto error;

> +	dyn->event = strdup(event+1);
> +	if (!dyn->event)
> +		goto error;

> +	if (desc->type == TRACE_DYNEVENT_SYNTH) {
> +		/* Synthetic events have no address */
> +		dyn->format = strdup(address+1);
> +		if (!dyn->format)
> +			goto error;
> +	} else {
> +		if (format)
> +			*format = '\0';
> +		dyn->address = strdup(address+1);
> +		if (!dyn->address)
> +			goto error;
> +		if (format) {
> +			dyn->format = strdup(format+1);
> +			if (!dyn->format)
> +				goto error;
> +		}

If strtok_r wasn't used, there's no reason to do all these "+1", you could
have just done:

	system++;
	event++;
	address++;
	format++;

It would have made it much cleaner.

> +	}
> +	*ret_dyn = dyn;
> +	return 0;
> +error:
> +	dynevent_free(dyn);
> +	return -1;
> +}
> +
> +int dyn_synth_del(struct dyn_events_desc *desc, struct tracefs_dynevent *dyn)
> +{
> +	char *str;
> +	int ret;
> +
> +	if (strcmp(desc->file, DYNEVENTS_EVENTS))
> +		return dyn_generic_del(desc, dyn);
> +
> +	ret = asprintf(&str, "!%s", dyn->event);
> +	if (ret < 0)
> +		return -1;
> +
> +	ret = tracefs_instance_file_append(NULL, desc->file, str);
> +	free(str);
> +
> +	return ret < 0 ? ret : 0;
> +}
> +
> +static int dyn_synth_parse(struct dyn_events_desc *desc, const char *group,
> +			   char *line, struct tracefs_dynevent **ret_dyn)
> +{
> +	struct tracefs_dynevent *dyn;
> +	char *format;
> +
> +	if (strcmp(desc->file, DYNEVENTS_EVENTS))
> +		return dyn_generic_parse(desc, group, line, ret_dyn);
> +
> +	/* synthetic_events file has slightly different syntax */
> +	format = strchr(line, ' ');
> +	if (!format)
> +		return -1;
> +	if (!ret_dyn)
> +		return 0;
> +
> +	*format = '\0';

strtok_r is your friend.

> +	dyn = calloc(1, sizeof(*dyn));
> +	if (!dyn)
> +		return -1;
> +	dyn->type = desc->type;
> +	dyn->trace_file = strdup(desc->file);
> +	if (!dyn->trace_file)
> +		goto error;
> +
> +	dyn->event = strdup(line);
> +	if (!dyn->event)
> +		goto error;
> +	dyn->format = strdup(format+1);
> +	if (!dyn->format)
> +		goto error;
> +
> +	*ret_dyn = dyn;
> +	return 0;
> +error:
> +	dynevent_free(dyn);
> +	return -1;
> +}
> +
> +static struct dyn_events_desc *get_devent_desc(enum trace_dynevent_type type)
> +{
> +	static bool init;
> +	int i;
> +
> +	if (init)
> +		goto out;
> +
> +	init = true;
> +	/* Use  ftrace dynamic_events, if available */
> +	if (tracefs_file_exists(NULL, DYNEVENTS_EVENTS)) {
> +		for (i = 0; i < TRACE_DYNEVENT_MAX; i++)
> +			dynevents[i].file = DYNEVENTS_EVENTS;
> +		goto out;
> +	}
> +
> +	if (tracefs_file_exists(NULL, KPROBE_EVENTS)) {
> +		dynevents[TRACE_DYNEVENT_KPROBE].file = KPROBE_EVENTS;
> +		dynevents[TRACE_DYNEVENT_KRETPROBE].file = KPROBE_EVENTS;
> +	}
> +	if (tracefs_file_exists(NULL, UPROBE_EVENTS)) {
> +		dynevents[TRACE_DYNEVENT_UPROBE].file = UPROBE_EVENTS;
> +		dynevents[TRACE_DYNEVENT_URETPROBE].file = UPROBE_EVENTS;
> +	}
> +	if (tracefs_file_exists(NULL, SYNTH_EVENTS)) {
> +		dynevents[TRACE_DYNEVENT_SYNTH].file = SYNTH_EVENTS;
> +		dynevents[TRACE_DYNEVENT_SYNTH].prefix = "";
> +	}
> +
> +out:
> +	return &dynevents[type];

I would break up the above into two functions.

static void init_devent_desc(void)
{
	int i;

	/* Use  ftrace dynamic_events, if available */
	if (tracefs_file_exists(NULL, DYNEVENTS_EVENTS)) {
		for (i = 0; i < TRACE_DYNEVENT_MAX; i++)
			dynevents[i].file = DYNEVENTS_EVENTS;
		goto out;
	}

	if (tracefs_file_exists(NULL, KPROBE_EVENTS)) {
		dynevents[TRACE_DYNEVENT_KPROBE].file = KPROBE_EVENTS;
		dynevents[TRACE_DYNEVENT_KRETPROBE].file = KPROBE_EVENTS;
	}
	if (tracefs_file_exists(NULL, UPROBE_EVENTS)) {
		dynevents[TRACE_DYNEVENT_UPROBE].file = UPROBE_EVENTS;
		dynevents[TRACE_DYNEVENT_URETPROBE].file = UPROBE_EVENTS;
	}
	if (tracefs_file_exists(NULL, SYNTH_EVENTS)) {
		dynevents[TRACE_DYNEVENT_SYNTH].file = SYNTH_EVENTS;
		dynevents[TRACE_DYNEVENT_SYNTH].prefix = "";
	}
}


static struct dyn_events_desc *get_devent_desc(enum trace_dynevent_type type)
{
	static bool init;

	if (!init) {
		init_devent_desc();
		init = true;
	}
	return &dynevents[type];
}



> +}
> +
> +__hidden struct tracefs_dynevent *
> +dynevent_alloc(enum trace_dynevent_type type, const char *system,
> +	       const char *event, const char *address, const char *format)
> +{
> +	struct tracefs_dynevent *devent;
> +	struct dyn_events_desc *desc;
> +
> +	if (!event) {
> +		errno = EINVAL;
> +		return NULL;
> +	}
> +
> +	desc = get_devent_desc(type);
> +	if (!desc || !desc->file) {
> +		errno = ENOTSUP;
> +		return NULL;
> +	}
> +
> +	devent = calloc(1, sizeof(*devent));
> +	if (!devent)
> +		return NULL;
> +
> +	devent->type = type;
> +	devent->trace_file = strdup(desc->file);
> +	if (!devent->trace_file)
> +		goto err;
> +	if (!system)
> +		system = DYNEVENTS_DEFAULT_GROUP;
> +	devent->system = strdup(system);
> +	if (!devent->system)
> +		goto err;
> +	devent->event = strdup(event);
> +	if (!devent->event)
> +		goto err;
> +	if (type == TRACE_DYNEVENT_KRETPROBE || type == TRACE_DYNEVENT_URETPROBE)
> +		devent->prefix = strdup(RETPROBE_DEFAUL_PREFIX);
> +	else
> +		devent->prefix = strdup(desc->prefix);
> +
> +	if (!devent->prefix)
> +		goto err;
> +	if (address) {
> +		devent->address = strdup(address);
> +		if (!devent->address)
> +			goto err;
> +	}
> +	if (format) {
> +		devent->format = strdup(format);
> +		if (!devent->format)
> +			goto err;
> +	}
> +
> +	return devent;
> +err:
> +	dynevent_free(devent);
> +	return NULL;
> +}
> +
> +__hidden int dynevent_create(struct tracefs_dynevent *devent)
> +{
> +	char *str;
> +	int ret;
> +
> +	if (!devent)
> +		return -1;

Again, space after error paths.

> +	if (devent->system && devent->system[0])
> +		ret = asprintf(&str, "%s%s/%s %s %s\n",
> +				devent->prefix, devent->system, devent->event,
> +				devent->address?devent->address:"",

Add spaces around "?" and ":" and for the ones below.

> +				devent->format?devent->format:"");
> +	else
> +		ret = asprintf(&str, "%s%s %s %s\n",
> +				devent->prefix, devent->event,
> +				devent->address?devent->address:"",
> +				devent->format?devent->format:"");
> +	if (ret < 0)
> +		return -1;

> +	ret = tracefs_instance_file_append(NULL, devent->trace_file, str);
> +	free(str);
> +
> +	return ret < 0 ? ret : 0;
> +}
> +
> +__hidden int dynevent_destroy(struct tracefs_dynevent *devent)
> +{
> +	struct dyn_events_desc *desc;
> +
> +	if (!devent)
> +		return -1;

space.

> +	desc = get_devent_desc(devent->type);
> +	if (!desc)
> +		return -1;

space.

> +	return desc->dyn_events_del(desc, devent);
> +}
> +
> +static int get_all_type(enum trace_dynevent_type type, const char *system,
> +			struct tracefs_dynevent ***ret_all)
> +{
> +	struct dyn_events_desc *desc;
> +	struct tracefs_dynevent *devent, **tmp, **all = NULL;
> +	char *content;
> +	int count = 0;
> +	char *line;
> +	char *next;
> +	int ret;
> +
> +	desc = get_devent_desc(type);
> +	if (!desc)
> +		return -1;
> +
> +	content = tracefs_instance_file_read(NULL, desc->file, NULL);
> +	if (!content)
> +		return -1;

space.

> +	line = content;
> +	do {
> +		next = strchr(line, '\n');
> +		if (next)
> +			*next = '\0';
> +		ret = desc->dyn_events_parse(desc, system, line, ret_all ? &devent : NULL);

So if ret_all is NULL, then we allocate a bunch of devent and lose them?

> +		if (!ret) {
> +			if (ret_all) {
> +				tmp = realloc(all, (count+1)*sizeof(struct tracefs_dynevent *));
> +				if (!tmp)
> +					goto error;
> +				all = tmp;
> +				all[count] = devent;
> +			}
> +			count++;
> +		}
> +		line = next + 1;
> +	} while (next);
> +
> +	free(content);
> +	if (ret_all)
> +		*ret_all = all;

We really should just return all, and if we want a count, we can pass a
pointer to an integer, and put the count in there. Not the other way around.

> +	return count;
> +
> +error:
> +	free(content);
> +	free(all);
> +	return -1;
> +}
> +
> +/**
> + * tracefs_dynevent_list_free - Deletes an array of pointers to dynamic event contexts
> + * @events: An array of pointers to dynamic event contexts. The last element of the array
> + *	    must be a NULL pointer.
> + */
> +void tracefs_dynevent_list_free(struct tracefs_dynevent ***events)

Again, just pass in ** not ***.

> +{
> +	struct tracefs_dynevent **devent;
> +	int i = 0;
> +
> +	if (!events || !(*events))
> +		return;
> +
> +	devent = *events;
> +	while (devent[i])
> +		dynevent_free(devent[i++]);
> +
> +	free(*events);
> +}
> +
> +__hidden int dynevent_get_all(unsigned long type_mask, const char *system,
> +			      struct tracefs_dynevent ***ret_events)
> +{
> +	struct tracefs_dynevent **events, **tmp, **all_events = NULL;
> +	int count, all = 0;
> +	int i;
> +
> +	for (i = 0; i < TRACE_DYNEVENT_MAX; i++) {
> +		if (!DYNEVENT_CHECK_BIT(type_mask, i))
> +			continue;

space.

> +		count = get_all_type(i, system, ret_events ? &events : NULL);
> +		if (count > 0) {
> +			if (ret_events) {
> +				tmp = realloc(all_events,
> +					     (all + count)*sizeof(struct tracefs_dynevent *));
> +				if (!tmp)
> +					goto error;
> +				all_events = tmp;
> +				memcpy(all_events + all, events,
> +				       count*sizeof(struct tracefs_dynevent *));
> +			}
> +			all += count;
> +		}
> +
> +	}
> +
> +	if (ret_events) {
> +		/* Add a NULL pointer at the end */
> +		if (all > 0) {
> +			tmp = realloc(all_events,
> +				     (all + 1)*sizeof(struct tracefs_dynevent *));
> +			if (!tmp)
> +				goto error;
> +			all_events = tmp;
> +			all_events[all] = NULL;
> +		}
> +		*ret_events = all_events;
> +	}
> +
> +	return all;
> +
> +error:
> +	if (all_events) {
> +		for (i = 0; i < all; i++)
> +			free(all_events[i]);
> +		free(all_events);
> +	}
> +	return -1;
> +}


-- Steve

Re: [PATCH 01/12] libtracefs: Add new internal APIs for dynamic events

[Tzvetomir Stoyanov]

On Fri, Oct 29, 2021 at 12:41 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Thu, 28 Oct 2021 15:08:56 +0300
> "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
>
[...]
> > +
> > +struct tracefs_dynevent *
> > +dynevent_alloc(enum trace_dynevent_type type, const char *system,
> > +            const char *event, const char *address, const char *format);
> > +void dynevent_free(struct tracefs_dynevent *devent);
> > +int dynevent_create(struct tracefs_dynevent *devent);
> > +int dynevent_destroy(struct tracefs_dynevent *devent);
> > +int dynevent_get_all(unsigned long type_mask, const char *system,
> > +                  struct tracefs_dynevent ***ret_events);
>
> I usually prefer to have a list returned, and NULL on error, instead of
> passing it in by reference. The "***" gets a bit out of hand.
>

The ret_events argument is optional, that's why it is passed as a
parameter. If ret_events is NULL, the API will return only the count
of the requested events. No array with events will be allocated in
that case.

>
> > +
> >  #endif /* _TRACE_FS_LOCAL_H */
> > diff --git a/include/tracefs.h b/include/tracefs.h
> > index a2cda30..4020551 100644
[ ... ]
> > +
> > +static int dyn_generic_parse(struct dyn_events_desc *desc, const char *group,
> > +                          char *line, struct tracefs_dynevent **ret_dyn)
>
> Again, I prefer to have the pointer returned, and not assigned as a
> parameter. All this returns is 0 on success or -1 on failure. That doesn't
> give us anything more than having ret_dyn allocated or not. (return NULL or
> non-NULL).
>

The ret_dyn is optional. If it is NULL, the function only checks if
the line contains an event of the requested type, without allocating
any memory.

> > +{
> > +     struct tracefs_dynevent *dyn;
> > +     char *address;
> > +     char *system;
> > +     char *format;
> > +     char *event;
> > +
> > +     if (strncmp(line, desc->prefix, strlen(desc->prefix)))
> > +             return -1;
> > +
> > +     system = strchr(line, ':');
> > +     if (!system)
> > +             return -1;
> > +     event = strchr(line, '/');
> > +     if (!event)
> > +             return -1;
> > +     address = strchr(line, ' ');
> > +     if (!address)
> > +             return -1;
> > +     format = strchr(address+1, ' ');
> > +
> > +     *address = '\0';
> > +     *event = '\0';
>
>
> The above should use strtok_r.
>
>         char *probe;
>         char *sav;
>
>         probe = strtok_r(line, ":", &sav);
>         system = strtok_r(NULL, "/", &sav);
>         event = strtok_r(NULL, " ", &sav);
>         address = strtok_r(NULL, " ", &sav);
>         format = strtok_r(NULL, "\n", &sav);
>

I used strchr() instead of strtok_r() here, because my original idea
was that this function should not modify the original line string, if
the event is not of the requested type. When parsing the
"dynamic_events" file, it contains events from any types. My initial
design was to pass the same line string to all parse functions, until
there is a match. But the design was changed, now a new copy of the
file is used for each event type. I'll change that code to use
strtok_r().

>
>
>
> > +
> > +     /* KPROBEs and UPROBEs share the same prefix, check the format */
> > +     if (desc->type == TRACE_DYNEVENT_UPROBE || desc->type == TRACE_DYNEVENT_URETPROBE) {
> > +             if (!strchr(format, '/'))
> > +                     return -1;
> > +     }
[ ... ]
> > +
> > +static int get_all_type(enum trace_dynevent_type type, const char *system,
> > +                     struct tracefs_dynevent ***ret_all)
> > +{
> > +     struct dyn_events_desc *desc;
> > +     struct tracefs_dynevent *devent, **tmp, **all = NULL;
> > +     char *content;
> > +     int count = 0;
> > +     char *line;
> > +     char *next;
> > +     int ret;
> > +
> > +     desc = get_devent_desc(type);
> > +     if (!desc)
> > +             return -1;
> > +
> > +     content = tracefs_instance_file_read(NULL, desc->file, NULL);
> > +     if (!content)
> > +             return -1;
>
> space.
>
> > +     line = content;
> > +     do {
> > +             next = strchr(line, '\n');
> > +             if (next)
> > +                     *next = '\0';
> > +             ret = desc->dyn_events_parse(desc, system, line, ret_all ? &devent : NULL);
>
> So if ret_all is NULL, then we allocate a bunch of devent and lose them?
>

Hm, no devents are allocated if ret_all is NULL. That's the idea of
that API design - ret_all is an optional input parameter. Without it,
the functions can be used only to get the count of the requested
events, without any memory allocation. I would like to keep that
functionality, even though it is not used at the moment.

> > +             if (!ret) {
> > +                     if (ret_all) {
> > +                             tmp = realloc(all, (count+1)*sizeof(struct tracefs_dynevent *));
> > +                             if (!tmp)
> > +                                     goto error;
> > +                             all = tmp;
> > +                             all[count] = devent;
> > +                     }
> > +                     count++;
> > +             }
> > +             line = next + 1;
> > +     } while (next);
> > +
> > +     free(content);
> > +     if (ret_all)
> > +             *ret_all = all;
>
> We really should just return all, and if we want a count, we can pass a
> pointer to an integer, and put the count in there. Not the other way around.
>
> > +     return count;
> > +
> > +error:
> > +     free(content);
> > +     free(all);
> > +     return -1;
> > +}
> > +
> > +/**
> > + * tracefs_dynevent_list_free - Deletes an array of pointers to dynamic event contexts
> > + * @events: An array of pointers to dynamic event contexts. The last element of the array
> > + *       must be a NULL pointer.
> > + */
> > +void tracefs_dynevent_list_free(struct tracefs_dynevent ***events)
>
> Again, just pass in ** not ***.
>
> > +{
> > +     struct tracefs_dynevent **devent;
> > +     int i = 0;
> > +
> > +     if (!events || !(*events))
> > +             return;
> > +
> > +     devent = *events;
> > +     while (devent[i])
> > +             dynevent_free(devent[i++]);
> > +
> > +     free(*events);
> > +}
> > +
> > +__hidden int dynevent_get_all(unsigned long type_mask, const char *system,
> > +                           struct tracefs_dynevent ***ret_events)
> > +{
> > +     struct tracefs_dynevent **events, **tmp, **all_events = NULL;
> > +     int count, all = 0;
> > +     int i;
> > +
> > +     for (i = 0; i < TRACE_DYNEVENT_MAX; i++) {
> > +             if (!DYNEVENT_CHECK_BIT(type_mask, i))
> > +                     continue;
>
> space.
>
> > +             count = get_all_type(i, system, ret_events ? &events : NULL);
> > +             if (count > 0) {
> > +                     if (ret_events) {
> > +                             tmp = realloc(all_events,
> > +                                          (all + count)*sizeof(struct tracefs_dynevent *));
> > +                             if (!tmp)
> > +                                     goto error;
> > +                             all_events = tmp;
> > +                             memcpy(all_events + all, events,
> > +                                    count*sizeof(struct tracefs_dynevent *));
> > +                     }
> > +                     all += count;
> > +             }
> > +
> > +     }
> > +
> > +     if (ret_events) {
> > +             /* Add a NULL pointer at the end */
> > +             if (all > 0) {
> > +                     tmp = realloc(all_events,
> > +                                  (all + 1)*sizeof(struct tracefs_dynevent *));
> > +                     if (!tmp)
> > +                             goto error;
> > +                     all_events = tmp;
> > +                     all_events[all] = NULL;
> > +             }
> > +             *ret_events = all_events;
> > +     }
> > +
> > +     return all;
> > +
> > +error:
> > +     if (all_events) {
> > +             for (i = 0; i < all; i++)
> > +                     free(all_events[i]);
> > +             free(all_events);
> > +     }
> > +     return -1;
> > +}
>
>
> -- Steve

Thanks Steven! I'll address these comments in the next version, but I
really want to keep the  dynevent_get_all() API more flexible - to
have a way to get only the count, without allocating an array with the
events.


-- 
Tzvetomir (Ceco) Stoyanov
VMware Open Source Technology Center

Re: [PATCH 03/12] libtracefs: New kprobes APIs

[Steven Rostedt]

On Thu, 28 Oct 2021 15:08:58 +0300
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> +static struct tracefs_dynevent *
> +kprobe_alloc(enum trace_dynevent_type type, const char *system, const char *event,
> +	     const char *addr, const char *format)
> +{
> +	struct tracefs_dynevent *kp;
> +	const char *sys = system;
> +	const char *ename = event;
> +	char *tmp;
> +
> +	if (!addr || !format) {
> +		errno = EBADMSG;
> +		return NULL;
> +	}
> +	if (!sys)
> +		sys = KPROBE_DEFAULT_GROUP;
> +
> +	if (!event) {
> +		ename = strdup(addr);
> +		if (!ename)
> +			return NULL;
> +		tmp = strchr(ename, ':');
> +		if (tmp)
> +			*tmp = '\0';
> +	}
> +
> +	kp = dynevent_alloc(type, sys, ename, addr, format);
> +	if (!event)
> +		free((char *)ename);
> +	if (!kp)
> +		return NULL;
> +	return kp;

If !kp is true, then return kp is the same as return NULL;

Nuke the "if (!kp)" code.

> +}
> +
> +

-- Steve

Re: [PATCH 05/12] libtracefs: Reimplement tracefs_kprobes_get API

[Steven Rostedt]

On Thu, 28 Oct 2021 15:09:00 +0300
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:

> In order to unify the code and reuse the internal helpers for dynamic
> events helpers, the tracefs_kprobes_get() API is reimplemented using
> the new dynamic events APIs.
> 
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
> ---
>  include/tracefs.h     |   2 +-
>  src/tracefs-kprobes.c | 127 +++++++++++-------------------------------
>  2 files changed, 33 insertions(+), 96 deletions(-)
> 
> diff --git a/include/tracefs.h b/include/tracefs.h
> index c7b9179..d4ac8fb 100644
> --- a/include/tracefs.h
> +++ b/include/tracefs.h
> @@ -259,7 +259,7 @@ int tracefs_kprobe_raw(const char *system, const char *event,
>  		       const char *addr, const char *format);
>  int tracefs_kretprobe_raw(const char *system, const char *event,
>  			  const char *addr, const char *format);
> -char **tracefs_kprobes_get(enum tracefs_kprobe_type type);
> +int tracefs_kprobes_get(enum tracefs_kprobe_type type, struct tracefs_dynevent ***kprobes);

Like I mentioned for the other patches. This should return the array,
and not be passing in an object to allocate.

General rule is, if you need to have a parameter with three
dereferences (***) you're doing it wrong. ;-)

>  enum tracefs_kprobe_type tracefs_kprobe_info(const char *group, const char *event,
>  					     char **type, char **addr, char **format);
>  
> diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c


-- Steve

Re: [PATCH 01/12] libtracefs: Add new internal APIs for dynamic events

[Steven Rostedt]

On Fri, 29 Oct 2021 05:46:42 +0300
Tzvetomir Stoyanov <tz.stoyanov@gmail.com> wrote:

> On Fri, Oct 29, 2021 at 12:41 AM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > On Thu, 28 Oct 2021 15:08:56 +0300
> > "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> wrote:
> >  
> [...]
> > > +
> > > +struct tracefs_dynevent *
> > > +dynevent_alloc(enum trace_dynevent_type type, const char *system,
> > > +            const char *event, const char *address, const char *format);
> > > +void dynevent_free(struct tracefs_dynevent *devent);
> > > +int dynevent_create(struct tracefs_dynevent *devent);
> > > +int dynevent_destroy(struct tracefs_dynevent *devent);
> > > +int dynevent_get_all(unsigned long type_mask, const char *system,
> > > +                  struct tracefs_dynevent ***ret_events);  
> >
> > I usually prefer to have a list returned, and NULL on error, instead of
> > passing it in by reference. The "***" gets a bit out of hand.
> >  
> 
> The ret_events argument is optional, that's why it is passed as a
> parameter. If ret_events is NULL, the API will return only the count
> of the requested events. No array with events will be allocated in
> that case.
> 

I would make a separate API for just the count, and not have this
function server two functionalities.

> >  
> > > +
> > >  #endif /* _TRACE_FS_LOCAL_H */
> > > diff --git a/include/tracefs.h b/include/tracefs.h
> > > index a2cda30..4020551 100644  
> [ ... ]
> > > +
> > > +static int dyn_generic_parse(struct dyn_events_desc *desc, const char *group,
> > > +                          char *line, struct tracefs_dynevent **ret_dyn)  
> >
> > Again, I prefer to have the pointer returned, and not assigned as a
> > parameter. All this returns is 0 on success or -1 on failure. That doesn't
> > give us anything more than having ret_dyn allocated or not. (return NULL or
> > non-NULL).
> >  
> 
> The ret_dyn is optional. If it is NULL, the function only checks if
> the line contains an event of the requested type, without allocating
> any memory.

I think we should make a separate API for that as well.

  dyn_generic_parse_check()?

> 
> > > +{
> > > +     struct tracefs_dynevent *dyn;
> > > +     char *address;
> > > +     char *system;
> > > +     char *format;
> > > +     char *event;
> > > +
> > > +     if (strncmp(line, desc->prefix, strlen(desc->prefix)))
> > > +             return -1;
> > > +
> > > +     system = strchr(line, ':');
> > > +     if (!system)
> > > +             return -1;
> > > +     event = strchr(line, '/');
> > > +     if (!event)
> > > +             return -1;
> > > +     address = strchr(line, ' ');
> > > +     if (!address)
> > > +             return -1;
> > > +     format = strchr(address+1, ' ');
> > > +
> > > +     *address = '\0';
> > > +     *event = '\0';  
> >
> >
> > The above should use strtok_r.
> >
> >         char *probe;
> >         char *sav;
> >
> >         probe = strtok_r(line, ":", &sav);
> >         system = strtok_r(NULL, "/", &sav);
> >         event = strtok_r(NULL, " ", &sav);
> >         address = strtok_r(NULL, " ", &sav);
> >         format = strtok_r(NULL, "\n", &sav);
> >  
> 
> I used strchr() instead of strtok_r() here, because my original idea
> was that this function should not modify the original line string, if
> the event is not of the requested type. When parsing the
> "dynamic_events" file, it contains events from any types. My initial
> design was to pass the same line string to all parse functions, until
> there is a match. But the design was changed, now a new copy of the
> file is used for each event type. I'll change that code to use
> strtok_r().
> 
> >
> >
> >  
> > > +
> > > +     /* KPROBEs and UPROBEs share the same prefix, check the format */
> > > +     if (desc->type == TRACE_DYNEVENT_UPROBE || desc->type == TRACE_DYNEVENT_URETPROBE) {
> > > +             if (!strchr(format, '/'))
> > > +                     return -1;
> > > +     }  
> [ ... ]
> > > +
> > > +static int get_all_type(enum trace_dynevent_type type, const char *system,
> > > +                     struct tracefs_dynevent ***ret_all)
> > > +{
> > > +     struct dyn_events_desc *desc;
> > > +     struct tracefs_dynevent *devent, **tmp, **all = NULL;
> > > +     char *content;
> > > +     int count = 0;
> > > +     char *line;
> > > +     char *next;
> > > +     int ret;
> > > +
> > > +     desc = get_devent_desc(type);
> > > +     if (!desc)
> > > +             return -1;
> > > +
> > > +     content = tracefs_instance_file_read(NULL, desc->file, NULL);
> > > +     if (!content)
> > > +             return -1;  
> >
> > space.
> >  
> > > +     line = content;
> > > +     do {
> > > +             next = strchr(line, '\n');
> > > +             if (next)
> > > +                     *next = '\0';
> > > +             ret = desc->dyn_events_parse(desc, system, line, ret_all ? &devent : NULL);  
> >
> > So if ret_all is NULL, then we allocate a bunch of devent and lose them?
> >  
> 
> Hm, no devents are allocated if ret_all is NULL. That's the idea of
> that API design - ret_all is an optional input parameter. Without it,
> the functions can be used only to get the count of the requested
> events, without any memory allocation. I would like to keep that
> functionality, even though it is not used at the moment.

Ah. But still, this is overly complex to try to have this server two
functionalities. It becomes confusing.


> 
> Thanks Steven! I'll address these comments in the next version, but I
> really want to keep the  dynevent_get_all() API more flexible - to
> have a way to get only the count, without allocating an array with the
> events.

I really think you should have that as two separate functions,
otherwise it becomes overly complex.

-- Steve