[PATCH v3 0/4] Separate trace-cmd and libtracecmd code

[PATCH v3 0/4] Separate trace-cmd and libtracecmd code

[Tzvetomir Stoyanov (VMware)]

libtracecmd is a library, containing functions that can be
used without the trace-cmd application. However, some of the
functions declared as libtracecmd APIs in trace-cmd.h
depend on trace-cmd context. That causes a problem when
other application uses the library. The problem can be
observed when running kerneshark and there is a python
module, loaded by the python plugin - there is a bunch
of warnings.
To resolve the problem, implementations of all trace-cmd
independent functions are moved into libtracecmd. All
libtracecmd functions, that depend on trace-cmd context
are removed from the library and from trace-cmd.h file.

[
  v3 changes:
   - Removed accepted patches from the series.
   - Added new patch: "Update descriptions of "debug" libtracecmd APIs".
   - Renamed "plog*" library APIs to "tracecmd_plog*".
   - Rmoved "tracecmd" prefix from local variables.
   - Renamed trace_set_log_file to tracecmd_set_logfile.
   - Changed tracecmd_set_quiet() and tracecmd_get_quiet() APIs to work
     per tracecmd_output handler.
 
  v2 changes:
   - Added a new patch: 
        Move trace-cmd-local.h from the application to the library.
   - Remove trace-output.c dependency of version.h. Moved FILE_VERSION_STRING
     define from top Makefile to trace-cmd-local.h.
]

Tzvetomir Stoyanov (VMware) (4):
  trace-cmd: Move trace-cmd global variable "quiet" to libtracecmd
  trace-cmd: Move plog() function to libtracecmd.
  trace-cmd: Move tracecmd_stack_tracer_status() function to libtracecmd
  trace-cmd: Update descriptions of "debug" libtracecmd APIs

 include/trace-cmd/trace-cmd.h           |   9 +-
 include/trace-cmd/trace-msg.h           |   3 -
 lib/trace-cmd/include/trace-cmd-local.h |   2 -
 lib/trace-cmd/trace-msg.c               |   8 +-
 lib/trace-cmd/trace-output.c            |  28 ++++-
 lib/trace-cmd/trace-util.c              | 139 ++++++++++++++++++++++--
 tracecmd/include/trace-local.h          |   2 -
 tracecmd/trace-cmd.c                    |   2 -
 tracecmd/trace-listen.c                 |  89 +++------------
 tracecmd/trace-record.c                 |  17 ++-
 tracecmd/trace-stack.c                  |  56 +---------
 11 files changed, 199 insertions(+), 156 deletions(-)

-- 
2.21.0

[PATCH v3 1/4] trace-cmd: Move trace-cmd global variable "quiet" to libtracecmd

[Tzvetomir Stoyanov (VMware)]

A trace-cmd global variable "quiet" is used from libtracecmd and
should be defined there. A new library APIs are implemented to
access it:
 void tracecmd_set_quiet(int quiet);
 int tracecmd_get_quiet(void);

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h           |  3 +++
 lib/trace-cmd/include/trace-cmd-local.h |  2 --
 lib/trace-cmd/trace-output.c            | 28 +++++++++++++++++++++++--
 tracecmd/include/trace-local.h          |  2 --
 tracecmd/trace-cmd.c                    |  2 --
 tracecmd/trace-record.c                 | 15 +++++++++----
 6 files changed, 40 insertions(+), 12 deletions(-)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index ede510c..f44f7a4 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -57,6 +57,9 @@ struct tracecmd_output;
 struct tracecmd_recorder;
 struct hook_list;
 
+void tracecmd_set_quiet(struct tracecmd_output *handle, bool set_quiet);
+bool tracecmd_get_quiet(struct tracecmd_output *handle);
+
 static inline int tracecmd_host_bigendian(void)
 {
 	unsigned char str[] = { 0x1, 0x2, 0x3, 0x4 };
diff --git a/lib/trace-cmd/include/trace-cmd-local.h b/lib/trace-cmd/include/trace-cmd-local.h
index bad325f..09574db 100644
--- a/lib/trace-cmd/include/trace-cmd-local.h
+++ b/lib/trace-cmd/include/trace-cmd-local.h
@@ -18,8 +18,6 @@
 #define STR(x)	_STR(x)
 #define FILE_VERSION_STRING STR(FILE_VERSION)
 
-extern int quiet;
-
 static ssize_t __do_write(int fd, const void *data, size_t size)
 {
 	ssize_t tot = 0;
diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index 1f94346..41932ee 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -53,6 +53,7 @@ struct tracecmd_output {
 	char			*tracing_dir;
 	int			options_written;
 	int			nr_options;
+	bool			quiet;
 	struct list_head 	options;
 	struct tracecmd_msg_handle *msg_handle;
 };
@@ -103,6 +104,29 @@ static unsigned long long convert_endian_8(struct tracecmd_output *handle,
 	return tep_read_number(handle->pevent, &val, 8);
 }
 
+/**
+ * tracecmd_set_quiet - Set if to print output to the screen
+ * @quiet: If non zero, print no output to the screen
+ *
+ */
+void tracecmd_set_quiet(struct tracecmd_output *handle, bool set_quiet)
+{
+	if (handle)
+		handle->quiet = set_quiet;
+}
+
+/**
+ * tracecmd_get_quiet - Get if to print output to the screen
+ * Returns non zero, if no output to the screen should be printed
+ *
+ */
+bool tracecmd_get_quiet(struct tracecmd_output *handle)
+{
+	if (handle)
+		return handle->quiet;
+	return false;
+}
+
 void tracecmd_output_free(struct tracecmd_output *handle)
 {
 	struct tracecmd_option *option;
@@ -1157,7 +1181,7 @@ int tracecmd_write_cpu_data(struct tracecmd_output *handle,
 		goto out_free;
 
 	for (i = 0; i < cpus; i++) {
-		if (!quiet)
+		if (!tracecmd_get_quiet(handle))
 			fprintf(stderr, "CPU%d data recorded at offset=0x%llx\n",
 				i, (unsigned long long) offsets[i]);
 		offset = lseek64(handle->fd, offsets[i], SEEK_SET);
@@ -1172,7 +1196,7 @@ int tracecmd_write_cpu_data(struct tracecmd_output *handle,
 			    check_size, sizes[i]);
 			goto out_free;
 		}
-		if (!quiet)
+		if (!tracecmd_get_quiet(handle))
 			fprintf(stderr, "    %llu bytes in size\n",
 				(unsigned long long)check_size);
 	}
diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index 7de5dd6..05760d8 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -12,8 +12,6 @@
 #include "trace-cmd.h"
 #include "event-utils.h"
 
-extern int quiet;
-
 /* fix stupid glib guint64 typecasts and printf formats */
 typedef unsigned long long u64;
 
diff --git a/tracecmd/trace-cmd.c b/tracecmd/trace-cmd.c
index 4add2e2..30691b6 100644
--- a/tracecmd/trace-cmd.c
+++ b/tracecmd/trace-cmd.c
@@ -16,8 +16,6 @@
 int silence_warnings;
 int show_status;
 
-int quiet;
-
 void warning(const char *fmt, ...)
 {
 	va_list ap;
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 7467b47..61457c8 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -80,6 +80,8 @@ static char *host;
 static unsigned int *client_ports;
 static int sfd;
 
+static bool quiet;
+
 /* Max size to let a per cpu file get */
 static int max_kb;
 
@@ -3162,13 +3164,16 @@ setup_connection(struct buffer_instance *instance, struct common_record_context
 	/* Now create the handle through this socket */
 	if (msg_handle->version == V3_PROTOCOL) {
 		network_handle = tracecmd_create_init_fd_msg(msg_handle, listed_events);
+		tracecmd_set_quiet(network_handle, quiet);
 		add_options(network_handle, ctx);
 		tracecmd_write_cpus(network_handle, instance->cpu_count);
 		tracecmd_write_options(network_handle);
 		tracecmd_msg_finish_sending_data(msg_handle);
-	} else
+	} else {
 		network_handle = tracecmd_create_init_fd_glob(msg_handle->fd,
 							      listed_events);
+		tracecmd_set_quiet(network_handle, quiet);
+	}
 
 	instance->network_handle = network_handle;
 
@@ -3444,9 +3449,10 @@ static void record_data(struct common_record_context *ctx)
 	if (!local)
 		return;
 
-	if (latency)
+	if (latency) {
 		handle = tracecmd_create_file_latency(output_file, local_cpu_count);
-	else {
+		tracecmd_set_quiet(handle, quiet);
+	} else {
 		if (!local_cpu_count)
 			return;
 
@@ -3478,6 +3484,7 @@ static void record_data(struct common_record_context *ctx)
 		handle = tracecmd_create_init_file_glob(output_file, listed_events);
 		if (!handle)
 			die("Error creating output file");
+		tracecmd_set_quiet(handle, quiet);
 
 		add_options(handle, ctx);
 
@@ -5155,7 +5162,7 @@ static void parse_record_options(int argc,
 			break;
 		case OPT_quiet:
 		case 'q':
-			quiet = 1;
+			quiet = true;
 			break;
 		default:
 			usage(argv);
-- 
2.21.0

[PATCH v3 2/4] trace-cmd: Move plog() function to libtracecmd.

[Tzvetomir Stoyanov (VMware)]

plog() function writes logs into a log file. It is used in
libtracecmd and its implementation should be there.
The function is moved from trace-cmd into the library and
renamed to tracecmd_plog(). Two additional APIs are implemented:
	int tracecmd_set_log_file(char *logfile); - use it to set
the log file.
	void tracecmd_plog_error(const char *fmt, ...); - use it to log
an error message into the file.

The plog() function is used also from pdie() in trace-cmd.
pdie() depends on trace-cmd context and cannot be moved to
the library. It is reimplemented as macros, in order to utilize
the new tracecmd_plog() library function.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h |  4 ++
 include/trace-cmd/trace-msg.h |  3 --
 lib/trace-cmd/trace-msg.c     |  8 ++--
 lib/trace-cmd/trace-util.c    | 70 +++++++++++++++++++++++++++
 tracecmd/trace-listen.c       | 89 +++++++----------------------------
 tracecmd/trace-record.c       |  2 +-
 6 files changed, 96 insertions(+), 80 deletions(-)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index f44f7a4..de3183d 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -389,6 +389,10 @@ struct hook_list {
 struct hook_list *tracecmd_create_event_hook(const char *arg);
 void tracecmd_free_hooks(struct hook_list *hooks);
 
+void tracecmd_plog(const char *fmt, ...);
+void tracecmd_plog_error(const char *fmt, ...);
+int tracecmd_set_logfile(char *logfile);
+
 /* --- Hack! --- */
 int tracecmd_blk_hack(struct tracecmd_input *handle);
 
diff --git a/include/trace-cmd/trace-msg.h b/include/trace-cmd/trace-msg.h
index b7fe10b..aab8a69 100644
--- a/include/trace-cmd/trace-msg.h
+++ b/include/trace-cmd/trace-msg.h
@@ -12,7 +12,4 @@
 
 extern unsigned int page_size;
 
-void plog(const char *fmt, ...);
-void pdie(const char *fmt, ...);
-
 #endif /* _TRACE_MSG_H_ */
diff --git a/lib/trace-cmd/trace-msg.c b/lib/trace-cmd/trace-msg.c
index 92562c7..74c5254 100644
--- a/lib/trace-cmd/trace-msg.c
+++ b/lib/trace-cmd/trace-msg.c
@@ -318,7 +318,7 @@ static int tracecmd_msg_recv(int fd, struct tracecmd_msg *msg)
 
 	return 0;
 error:
-	plog("Receive an invalid message(size=%d)\n", size);
+	tracecmd_plog("Receive an invalid message(size=%d)\n", size);
 	return -ENOMSG;
 }
 
@@ -531,7 +531,7 @@ int tracecmd_msg_initial_setting(struct tracecmd_msg_handle *msg_handle)
 	}
 
 	cpus = ntohl(msg.tinit.cpus);
-	plog("cpus=%d\n", cpus);
+	tracecmd_plog("cpus=%d\n", cpus);
 	if (cpus < 0) {
 		ret = -EINVAL;
 		goto error;
@@ -540,7 +540,7 @@ int tracecmd_msg_initial_setting(struct tracecmd_msg_handle *msg_handle)
 	msg_handle->cpu_count = cpus;
 
 	pagesize = ntohl(msg.tinit.page_size);
-	plog("pagesize=%d\n", pagesize);
+	tracecmd_plog("pagesize=%d\n", pagesize);
 	if (pagesize <= 0) {
 		ret = -EINVAL;
 		goto error;
@@ -570,7 +570,7 @@ int tracecmd_msg_initial_setting(struct tracecmd_msg_handle *msg_handle)
 
 		/* do we understand this option? */
 		if (!process_option(msg_handle, p))
-			plog("Cannot understand option '%s'\n", p);
+			tracecmd_plog("Cannot understand option '%s'\n", p);
 
 		p = strchr(p, '\0');
 	}
diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
index faff0b5..60bcb68 100644
--- a/lib/trace-cmd/trace-util.c
+++ b/lib/trace-cmd/trace-util.c
@@ -30,6 +30,8 @@ int tracecmd_disable_sys_plugins;
 int tracecmd_disable_plugins;
 static bool tracecmd_debug;
 
+static FILE *logfp;
+
 static struct registered_plugin_options {
 	struct registered_plugin_options	*next;
 	struct tep_plugin_option			*options;
@@ -1695,3 +1697,71 @@ void __weak *malloc_or_die(unsigned int size)
 		die("malloc");
 	return data;
 }
+
+#define LOG_BUF_SIZE 1024
+static void __plog(const char *prefix, const char *fmt, va_list ap, FILE *fp)
+{
+	static int newline = 1;
+	char buf[LOG_BUF_SIZE];
+	int r;
+
+	r = vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
+
+	if (r > LOG_BUF_SIZE)
+		r = LOG_BUF_SIZE;
+
+	if (logfp) {
+		if (newline)
+			fprintf(logfp, "[%d]%s%.*s", getpid(), prefix, r, buf);
+		else
+			fprintf(logfp, "[%d]%s%.*s", getpid(), prefix, r, buf);
+		newline = buf[r - 1] == '\n';
+		fflush(logfp);
+		return;
+	}
+
+	fprintf(fp, "%.*s", r, buf);
+}
+
+void tracecmd_plog(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	__plog("", fmt, ap, stdout);
+	va_end(ap);
+	/* Make sure it gets to the screen, in case we crash afterward */
+	fflush(stdout);
+}
+
+void tracecmd_plog_error(const char *fmt, ...)
+{
+	va_list ap;
+	char *str = "";
+
+	va_start(ap, fmt);
+	__plog("Error: ", fmt, ap, stderr);
+	va_end(ap);
+	if (errno)
+		str = strerror(errno);
+	if (logfp)
+		fprintf(logfp, "\n%s\n", str);
+	else
+		fprintf(stderr, "\n%s\n", str);
+}
+
+/**
+ * tracecmd_set_logfile - Set file for logging
+ * @logfile: Name of the log file
+ *
+ * Returns 0 on successful completion or -1 in case of error
+ */
+int tracecmd_set_logfile(char *logfile)
+{
+	if (logfp)
+		fclose(logfp);
+	logfp = fopen(logfile, "w");
+	if (!logfp)
+		return -1;
+	return 0;
+}
diff --git a/tracecmd/trace-listen.c b/tracecmd/trace-listen.c
index 9dcb833..233d661 100644
--- a/tracecmd/trace-listen.c
+++ b/tracecmd/trace-listen.c
@@ -34,8 +34,6 @@ static char *output_dir;
 static char *default_output_file = "trace";
 static char *output_file;
 
-static FILE *logfp;
-
 static int backlog = 5;
 
 static int do_daemon;
@@ -44,6 +42,13 @@ static int do_daemon;
 static struct tracecmd_msg_handle *stop_msg_handle;
 static bool done;
 
+#define pdie(fmt, ...)					\
+	do {						\
+		tracecmd_plog_error(fmt, ##__VA_ARGS__);\
+		remove_pid_file();			\
+		exit(-1);				\
+	} while (0)
+
 #define  TEMP_FILE_STR "%s.%s:%s.cpu%d", output_file, host, port, cpu
 static char *get_temp_file(const char *host, const char *port, int cpu)
 {
@@ -114,43 +119,6 @@ static void finish(int sig)
 	done = true;
 }
 
-#define LOG_BUF_SIZE 1024
-static void __plog(const char *prefix, const char *fmt, va_list ap,
-		   FILE *fp)
-{
-	static int newline = 1;
-	char buf[LOG_BUF_SIZE];
-	int r;
-
-	r = vsnprintf(buf, LOG_BUF_SIZE, fmt, ap);
-
-	if (r > LOG_BUF_SIZE)
-		r = LOG_BUF_SIZE;
-
-	if (logfp) {
-		if (newline)
-			fprintf(logfp, "[%d]%s%.*s", getpid(), prefix, r, buf);
-		else
-			fprintf(logfp, "[%d]%s%.*s", getpid(), prefix, r, buf);
-		newline = buf[r - 1] == '\n';
-		fflush(logfp);
-		return;
-	}
-
-	fprintf(fp, "%.*s", r, buf);
-}
-
-void plog(const char *fmt, ...)
-{
-	va_list ap;
-
-	va_start(ap, fmt);
-	__plog("", fmt, ap, stdout);
-	va_end(ap);
-	/* Make sure it gets to the screen, in case we crash afterward */
-	fflush(stdout);
-}
-
 static void make_pid_name(int mode, char *buf)
 {
 	snprintf(buf, PATH_MAX, VAR_RUN_DIR "/trace-cmd-net.pid");
@@ -169,26 +137,6 @@ static void remove_pid_file(void)
 	unlink(buf);
 }
 
-void pdie(const char *fmt, ...)
-{
-	va_list ap;
-	char *str = "";
-
-	va_start(ap, fmt);
-	__plog("Error: ", fmt, ap, stderr);
-	va_end(ap);
-	if (errno)
-		str = strerror(errno);
-	if (logfp)
-		fprintf(logfp, "\n%s\n", str);
-	else
-		fprintf(stderr, "\n%s\n", str);
-
-	remove_pid_file();
-
-	exit(-1);
-}
-
 static int process_udp_child(int sfd, const char *host, const char *port,
 			     int cpu, int page_size, int use_tcp)
 {
@@ -369,15 +317,15 @@ static int communicate_with_client(struct tracecmd_msg_handle *msg_handle)
 		if (memcmp(buf, V3_CPU, n) != 0) {
 			/* If it did not send a version, then bail */
 			if (memcmp(buf, "-1V", 3)) {
-				plog("Unknown string %s\n", buf);
+				tracecmd_plog("Unknown string %s\n", buf);
 				goto out;
 			}
 			/* Skip "-1" */
-			plog("Cannot handle the protocol %s\n", buf+2);
+			tracecmd_plog("Cannot handle the protocol %s\n", buf+2);
 
 			/* If it returned the same command as last time, bail! */
 			if (last_proto && strncmp(last_proto, buf, n) == 0) {
-				plog("Repeat of version %s sent\n", last_proto);
+				tracecmd_plog("Repeat of version %s sent\n", last_proto);
 				goto out;
 			}
 			free(last_proto);
@@ -410,7 +358,7 @@ static int communicate_with_client(struct tracecmd_msg_handle *msg_handle)
 	} else {
 		/* The client is using the v1 protocol */
 
-		plog("cpus=%d\n", cpus);
+		tracecmd_plog("cpus=%d\n", cpus);
 		if (cpus < 0)
 			goto out;
 
@@ -424,7 +372,7 @@ static int communicate_with_client(struct tracecmd_msg_handle *msg_handle)
 
 		pagesize = atoi(buf);
 
-		plog("pagesize=%d\n", pagesize);
+		tracecmd_plog("pagesize=%d\n", pagesize);
 		if (pagesize <= 0)
 			goto out;
 
@@ -473,7 +421,7 @@ static int communicate_with_client(struct tracecmd_msg_handle *msg_handle)
 	}
 
 	if (msg_handle->flags & TRACECMD_MSG_FL_USE_TCP)
-		plog("Using TCP for live connection\n");
+		tracecmd_plog("Using TCP for live connection\n");
 
 	ret = pagesize;
  out:
@@ -560,7 +508,7 @@ static int *create_all_readers(const char *node, const char *port,
 	if (msg_handle->version == V3_PROTOCOL) {
 		/* send set of port numbers to the client */
 		if (tracecmd_msg_send_port_array(msg_handle, port_array) < 0) {
-			plog("Failed sending port array\n");
+			tracecmd_plog("Failed sending port array\n");
 			goto out_free;
 		}
 	} else {
@@ -755,11 +703,9 @@ static int do_connection(int cfd, struct sockaddr_storage *peer_addr,
 			service, NI_MAXSERV, NI_NUMERICSERV);
 
 	if (s == 0)
-		plog("Connected with %s:%s\n",
-		       host, service);
+		tracecmd_plog("Connected with %s:%s\n", host, service);
 	else {
-		plog("Error with getnameinfo: %s\n",
-		       gai_strerror(s));
+		tracecmd_plog("Error with getnameinfo: %s\n", gai_strerror(s));
 		close(cfd);
 		tracecmd_msg_handle_close(msg_handle);
 		return -1;
@@ -1030,8 +976,7 @@ void trace_listen(int argc, char **argv)
 
 	if (logfile) {
 		/* set the writes to a logfile instead */
-		logfp = fopen(logfile, "w");
-		if (!logfp)
+		if (tracecmd_set_logfile(logfile) < 0)
 			die("creating log file %s", logfile);
 	}
 
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 61457c8..96d2c1a 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -3055,7 +3055,7 @@ static void check_protocol_version(struct tracecmd_msg_handle *msg_handle)
 	if (n < 0 || !buf[0]) {
 		/* the server uses the v1 protocol, so we'll use it */
 		msg_handle->version = V1_PROTOCOL;
-		plog("Use the v1 protocol\n");
+		tracecmd_plog("Use the v1 protocol\n");
 	} else {
 		if (memcmp(buf, "V3", n) != 0)
 			die("Cannot handle the protocol %s", buf);
-- 
2.21.0

[PATCH v3 3/4] trace-cmd: Move tracecmd_stack_tracer_status() function to libtracecmd

[Tzvetomir Stoyanov (VMware)]

tracecmd_stack_tracer_status() function reads the stack tracer status
from the proc file system. It does not depend on trace-cmd context and
can be used standalone. The function is moved from trace-cmd application
into libtracecmd.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/trace-util.c | 51 ++++++++++++++++++++++++++++++++++
 tracecmd/trace-stack.c     | 56 ++------------------------------------
 2 files changed, 53 insertions(+), 54 deletions(-)

diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
index 60bcb68..6e2a352 100644
--- a/lib/trace-cmd/trace-util.c
+++ b/lib/trace-cmd/trace-util.c
@@ -25,6 +25,7 @@
 #define LOCAL_PLUGIN_DIR ".trace-cmd/plugins"
 #define TRACEFS_PATH "/sys/kernel/tracing"
 #define DEBUGFS_PATH "/sys/kernel/debug"
+#define PROC_STACK_FILE "/proc/sys/kernel/stack_tracer_enabled"
 
 int tracecmd_disable_sys_plugins;
 int tracecmd_disable_plugins;
@@ -1765,3 +1766,53 @@ int tracecmd_set_logfile(char *logfile)
 		return -1;
 	return 0;
 }
+
+/**
+ * tracecmd_stack_tracer_status - Check stack trace status
+ * @status: Returned stack trace status:
+ *             0 - not configured, disabled
+ *             non 0 - enabled
+ *
+ * Returns -1 in case of an error, 0 if file does not exist
+ * (stack tracer not configured in kernel) or 1 on successful completion.
+ */
+int tracecmd_stack_tracer_status(int *status)
+{
+	struct stat stat_buf;
+	char buf[64];
+	long num;
+	int fd;
+	int n;
+
+	if (stat(PROC_STACK_FILE, &stat_buf) < 0) {
+		/* stack tracer not configured on running kernel */
+		*status = 0; /* not configured means disabled */
+		return 0;
+	}
+
+	fd = open(PROC_STACK_FILE, O_RDONLY);
+
+	if (fd < 0)
+		return -1;
+
+	n = read(fd, buf, sizeof(buf));
+	close(fd);
+
+	if (n <= 0)
+		return -1;
+
+	if (n >= sizeof(buf))
+		return -1;
+
+	buf[n] = 0;
+
+	errno = 0;
+	num = strtol(buf, NULL, 10);
+
+	/* Check for various possible errors */
+	if (num > INT_MAX || num < INT_MIN || (!num && errno))
+		return -1;
+
+	*status = num;
+	return 1; /* full success */
+}
diff --git a/tracecmd/trace-stack.c b/tracecmd/trace-stack.c
index 34b3b58..bb002c0 100644
--- a/tracecmd/trace-stack.c
+++ b/tracecmd/trace-stack.c
@@ -36,58 +36,6 @@ static void test_available(void)
 		die("stack tracer not configured on running kernel");
 }
 
-/*
- * Returns:
- *   -1 - Something went wrong
- *    0 - File does not exist (stack tracer not enabled)
- *    1 - Success
- */
-static int read_proc(int *status)
-{
-	struct stat stat_buf;
-	char buf[64];
-	long num;
-	int fd;
-	int n;
-
-	if (stat(PROC_FILE, &stat_buf) < 0) {
-		/* stack tracer not configured on running kernel */
-		*status = 0; /* not configured means disabled */
-		return 0;
-	}
-
-	fd = open(PROC_FILE, O_RDONLY);
-
-	if (fd < 0)
-		return -1;
-
-	n = read(fd, buf, sizeof(buf));
-	close(fd);
-
-	if (n <= 0)
-		return -1;
-
-	if (n >= sizeof(buf))
-		return -1;
-
-	buf[n] = 0;
-	errno = 0;
-	num = strtol(buf, NULL, 10);
-
-	/* Check for various possible errors */
-	if (num > INT_MAX || num < INT_MIN || (!num && errno))
-		return -1;
-
-	*status = num;
-	return 1; /* full success */
-}
-
-/* Public wrapper of read_proc() */
-int tracecmd_stack_tracer_status(int *status)
-{
-	return read_proc(status);
-}
-
 /* NOTE: this implementation only accepts new_status in the range [0..9]. */
 static void change_stack_tracer_status(unsigned new_status)
 {
@@ -102,7 +50,7 @@ static void change_stack_tracer_status(unsigned new_status)
 		return;
 	}
 
-	ret = read_proc(&status);
+	ret = tracecmd_stack_tracer_status(&status);
 	if (ret < 0)
 		die("error reading %s", PROC_FILE);
 
@@ -160,7 +108,7 @@ static void read_trace(void)
 	size_t n;
 	int r;
 
-	if (read_proc(&status) <= 0)
+	if (tracecmd_stack_tracer_status(&status) <= 0)
 		die("Invalid stack tracer state");
 
 	if (status > 0)
-- 
2.21.0

[PATCH v3 4/4] trace-cmd: Update descriptions of "debug" libtracecmd APIs

[Tzvetomir Stoyanov (VMware)]

The description of "debug" libtracecmd APIs:
 tracecmd_set_debug()
 tracecmd_get_debug()
does not match the functions. There was a copy leftover from
"quiet" APIs.
The name of the local static variable is changed form tracecmd_debug to
debug, as it is not visible outside of the library.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 include/trace-cmd/trace-cmd.h |  2 +-
 lib/trace-cmd/trace-util.c    | 18 +++++++++---------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index de3183d..3c5e827 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -49,7 +49,7 @@ enum {
 void tracecmd_record_ref(struct tep_record *record);
 void free_record(struct tep_record *record);
 
-void tracecmd_set_debug(bool debug);
+void tracecmd_set_debug(bool set_debug);
 bool tracecmd_get_debug(void);
 
 struct tracecmd_input;
diff --git a/lib/trace-cmd/trace-util.c b/lib/trace-cmd/trace-util.c
index 6e2a352..6a53004 100644
--- a/lib/trace-cmd/trace-util.c
+++ b/lib/trace-cmd/trace-util.c
@@ -29,7 +29,7 @@
 
 int tracecmd_disable_sys_plugins;
 int tracecmd_disable_plugins;
-static bool tracecmd_debug;
+static bool debug;
 
 static FILE *logfp;
 
@@ -101,23 +101,23 @@ char **trace_util_list_plugin_options(void)
 }
 
 /**
- * tracecmd_set_quiet - Set if to print output to the screen
- * @quiet: If non zero, print no output to the screen
- *
+ * tracecmd_set_debug - Set debug mode of the tracecmd library
+ * @set_debug: The new "debug" mode. If true, the tracecmd library is
+ * in "debug" mode
  */
-void tracecmd_set_debug(bool debug)
+void tracecmd_set_debug(bool set_debug)
 {
-	tracecmd_debug = debug;
+	debug = set_debug;
 }
 
 /**
- * tracecmd_get_quiet - Get if to print output to the screen
- * Returns non zero, if no output to the screen should be printed
+ * tracecmd_get_debug - Get debug mode of tracecmd library
+ * Returns true, if the tracecmd library is in debug mode.
  *
  */
 bool tracecmd_get_debug(void)
 {
-	return tracecmd_debug;
+	return debug;
 }
 
 void trace_util_free_plugin_options_list(char **list)
-- 
2.21.0