[PATCH 0/4] trace-cmd: Clean ups for agent communications

[PATCH 0/4] trace-cmd: Clean ups for agent communications

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

In preparation to have an agent proxy, these are some clean up patches to
the agent code that should help simplify the modifications.

Steven Rostedt (Google) (4):
  trace-cmd: Move add_guest_info() into trace-vm.c
  trace-cmd: Simplify add_guest()
  trace-cmd: Move find_tasks() into add_guest()
  trace-cmd: Move find_pid_by_cid() into add_guest()

 tracecmd/include/trace-local.h |   1 +
 tracecmd/trace-record.c        |  89 +------------------------
 tracecmd/trace-vm.c            | 117 ++++++++++++++++++++++++++++-----
 3 files changed, 104 insertions(+), 103 deletions(-)

-- 
2.35.1

[PATCH 1/4] trace-cmd: Move add_guest_info() into trace-vm.c

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

In preparation for the agent proxy, move add_guest_info() into trace-vm.c
and rename it to trace_add_guest_info(). This will be used by the agent
when acting as a proxy.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 tracecmd/include/trace-local.h |  1 +
 tracecmd/trace-record.c        | 54 +---------------------------------
 tracecmd/trace-vm.c            | 52 ++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 53 deletions(-)

diff --git a/tracecmd/include/trace-local.h b/tracecmd/include/trace-local.h
index e3fec1319880..f3b805fa7bad 100644
--- a/tracecmd/include/trace-local.h
+++ b/tracecmd/include/trace-local.h
@@ -339,6 +339,7 @@ bool trace_have_guests_pid(void);
 void read_qemu_guests(void);
 int get_guest_pid(unsigned int guest_cid);
 int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu);
+void trace_add_guest_info(struct tracecmd_output *handle, struct buffer_instance *instance);
 
 /* moved from trace-cmd.h */
 void tracecmd_remove_instances(void);
diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index 27c4e7ba6f3f..d4b5d4d6490f 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -4297,58 +4297,6 @@ static void append_buffer(struct tracecmd_output *handle,
 	}
 }
 
-static void
-add_guest_info(struct tracecmd_output *handle, struct buffer_instance *instance)
-{
-	struct trace_guest *guest;
-	const char *name;
-	char *buf, *p;
-	int size;
-	int pid;
-	int i;
-
-	if (is_network(instance)) {
-		name = instance->name;
-	} else {
-		guest = trace_get_guest(instance->cid, NULL);
-		if (!guest)
-			return;
-		name = guest->name;
-	}
-
-	size = strlen(name) + 1;
-	size += sizeof(long long);	/* trace_id */
-	size += sizeof(int);		/* cpu count */
-	size += instance->cpu_count * 2 * sizeof(int);	/* cpu,pid pair */
-
-	buf = calloc(1, size);
-	if (!buf)
-		return;
-	p = buf;
-	strcpy(p, name);
-	p += strlen(name) + 1;
-
-	memcpy(p, &instance->trace_id, sizeof(long long));
-	p += sizeof(long long);
-
-	memcpy(p, &instance->cpu_count, sizeof(int));
-	p += sizeof(int);
-	for (i = 0; i < instance->cpu_count; i++) {
-		pid = -1;
-		if (!is_network(instance)) {
-			if (i < guest->cpu_max)
-				pid = guest->cpu_pid[i];
-		}
-		memcpy(p, &i, sizeof(int));
-		p += sizeof(int);
-		memcpy(p, &pid, sizeof(int));
-		p += sizeof(int);
-	}
-
-	tracecmd_add_option(handle, TRACECMD_OPTION_GUEST, size, buf);
-	free(buf);
-}
-
 static void
 add_pid_maps(struct tracecmd_output *handle, struct buffer_instance *instance)
 {
@@ -4679,7 +4627,7 @@ static void record_data(struct common_record_context *ctx)
 
 		for_all_instances(instance) {
 			if (is_guest(instance))
-				add_guest_info(handle, instance);
+				trace_add_guest_info(handle, instance);
 		}
 
 		if (ctx->tsc2nsec.mult) {
diff --git a/tracecmd/trace-vm.c b/tracecmd/trace-vm.c
index 57dbef8d42e4..281843b223f6 100644
--- a/tracecmd/trace-vm.c
+++ b/tracecmd/trace-vm.c
@@ -386,3 +386,55 @@ int get_guest_vcpu_pid(unsigned int guest_cid, unsigned int guest_vcpu)
 	}
 	return -1;
 }
+
+void
+trace_add_guest_info(struct tracecmd_output *handle, struct buffer_instance *instance)
+{
+	struct trace_guest *guest;
+	const char *name;
+	char *buf, *p;
+	int size;
+	int pid;
+	int i;
+
+	if (is_network(instance)) {
+		name = instance->name;
+	} else {
+		guest = trace_get_guest(instance->cid, NULL);
+		if (!guest)
+			return;
+		name = guest->name;
+	}
+
+	size = strlen(name) + 1;
+	size += sizeof(long long);	/* trace_id */
+	size += sizeof(int);		/* cpu count */
+	size += instance->cpu_count * 2 * sizeof(int);	/* cpu,pid pair */
+
+	buf = calloc(1, size);
+	if (!buf)
+		return;
+	p = buf;
+	strcpy(p, name);
+	p += strlen(name) + 1;
+
+	memcpy(p, &instance->trace_id, sizeof(long long));
+	p += sizeof(long long);
+
+	memcpy(p, &instance->cpu_count, sizeof(int));
+	p += sizeof(int);
+	for (i = 0; i < instance->cpu_count; i++) {
+		pid = -1;
+		if (!is_network(instance)) {
+			if (i < guest->cpu_max)
+				pid = guest->cpu_pid[i];
+		}
+		memcpy(p, &i, sizeof(int));
+		p += sizeof(int);
+		memcpy(p, &pid, sizeof(int));
+		p += sizeof(int);
+	}
+
+	tracecmd_add_option(handle, TRACECMD_OPTION_GUEST, size, buf);
+	free(buf);
+}
-- 
2.35.1

[PATCH 2/4] trace-cmd: Simplify add_guest()

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

Simplify the function add_guest by using a local variable to point to the
array element instead of dereferencing the array every time.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 tracecmd/trace-vm.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/tracecmd/trace-vm.c b/tracecmd/trace-vm.c
index 281843b223f6..f0513950aa26 100644
--- a/tracecmd/trace-vm.c
+++ b/tracecmd/trace-vm.c
@@ -56,18 +56,22 @@ bool trace_have_guests_pid(void)
 
 static struct trace_guest *add_guest(unsigned int cid, const char *name)
 {
+	struct trace_guest *guest;
+
 	guests = realloc(guests, (guests_len + 1) * sizeof(*guests));
 	if (!guests)
 		die("allocating new guest");
-	memset(&guests[guests_len], 0, sizeof(struct trace_guest));
-	guests[guests_len].name = strdup(name);
-	if (!guests[guests_len].name)
+
+	guest = &guests[guests_len++];
+
+	memset(guest, 0, sizeof(*guest));
+	guest->name = strdup(name);
+	if (!guest->name)
 		die("allocating guest name");
-	guests[guests_len].cid = cid;
-	guests[guests_len].pid = -1;
-	guests_len++;
+	guest->cid = cid;
+	guest->pid = -1;
 
-	return &guests[guests_len - 1];
+	return guest;
 }
 
 static struct tracefs_instance *start_trace_connect(void)
-- 
2.35.1

[PATCH 3/4] trace-cmd: Move find_tasks() into add_guest()

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

In order to simplify the logic a bit, move the find_tasks() code (to find
the PIDs on the host that map to the guest) into the add_guest() function
where the guest is first added.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 tracecmd/trace-record.c | 35 -----------------------------------
 tracecmd/trace-vm.c     | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 35 deletions(-)

diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index d4b5d4d6490f..a4a0d63d907d 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -3215,38 +3215,6 @@ static int do_accept(int sd)
 	return -1;
 }
 
-/* Find all the tasks associated with the guest pid */
-static void find_tasks(struct trace_guest *guest)
-{
-	struct dirent *dent;
-	char *path;
-	DIR *dir;
-	int ret;
-	int tasks = 0;
-
-	ret = asprintf(&path, "/proc/%d/task", guest->pid);
-	if (ret < 0)
-		return;
-
-	dir = opendir(path);
-	free(path);
-	if (!dir)
-		return;
-
-	while ((dent = readdir(dir))) {
-		int *pids;
-		if (!(dent->d_type == DT_DIR && is_digits(dent->d_name)))
-			continue;
-		pids = realloc(guest->task_pids, sizeof(int) * (tasks + 2));
-		if (!pids)
-			break;
-		pids[tasks++] = strtol(dent->d_name, NULL, 0);
-		pids[tasks] = -1;
-		guest->task_pids = pids;
-	}
-	closedir(dir);
-}
-
 static char *parse_guest_name(char *gname, int *cid, int *port,
 			      struct addrinfo **res)
 {
@@ -3287,9 +3255,6 @@ static char *parse_guest_name(char *gname, int *cid, int *port,
 		guest = trace_get_guest(*cid, gname);
 	if (guest) {
 		*cid = guest->cid;
-		/* Mapping not found, search for them */
-		if (!guest->cpu_pid)
-			find_tasks(guest);
 		return guest->name;
 	}
 
diff --git a/tracecmd/trace-vm.c b/tracecmd/trace-vm.c
index f0513950aa26..bf2b0695d09b 100644
--- a/tracecmd/trace-vm.c
+++ b/tracecmd/trace-vm.c
@@ -54,6 +54,38 @@ bool trace_have_guests_pid(void)
 	return true;
 }
 
+/* Find all the tasks associated with the guest pid */
+static void find_tasks(struct trace_guest *guest)
+{
+	struct dirent *dent;
+	char *path;
+	DIR *dir;
+	int ret;
+	int tasks = 0;
+
+	ret = asprintf(&path, "/proc/%d/task", guest->pid);
+	if (ret < 0)
+		return;
+
+	dir = opendir(path);
+	free(path);
+	if (!dir)
+		return;
+
+	while ((dent = readdir(dir))) {
+		int *pids;
+		if (!(dent->d_type == DT_DIR && is_digits(dent->d_name)))
+			continue;
+		pids = realloc(guest->task_pids, sizeof(int) * (tasks + 2));
+		if (!pids)
+			break;
+		pids[tasks++] = strtol(dent->d_name, NULL, 0);
+		pids[tasks] = -1;
+		guest->task_pids = pids;
+	}
+	closedir(dir);
+}
+
 static struct trace_guest *add_guest(unsigned int cid, const char *name)
 {
 	struct trace_guest *guest;
@@ -71,6 +103,8 @@ static struct trace_guest *add_guest(unsigned int cid, const char *name)
 	guest->cid = cid;
 	guest->pid = -1;
 
+	find_tasks(guest);
+
 	return guest;
 }
 
-- 
2.35.1

[PATCH 4/4] trace-cmd: Move find_pid_by_cid() into add_guest()

[Steven Rostedt]

From: "Steven Rostedt (Google)" <rostedt@goodmis.org>

To simplify the code even more, move the find_pid_by_cid() into
add_guest() to map the main pid process to the cid.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 tracecmd/trace-vm.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/tracecmd/trace-vm.c b/tracecmd/trace-vm.c
index bf2b0695d09b..cabe4baffecb 100644
--- a/tracecmd/trace-vm.c
+++ b/tracecmd/trace-vm.c
@@ -86,6 +86,8 @@ static void find_tasks(struct trace_guest *guest)
 	closedir(dir);
 }
 
+static void find_pid_by_cid(struct trace_guest *guest);
+
 static struct trace_guest *add_guest(unsigned int cid, const char *name)
 {
 	struct trace_guest *guest;
@@ -103,6 +105,7 @@ static struct trace_guest *add_guest(unsigned int cid, const char *name)
 	guest->cid = cid;
 	guest->pid = -1;
 
+	find_pid_by_cid(guest);
 	find_tasks(guest);
 
 	return guest;
@@ -341,11 +344,8 @@ struct trace_guest *trace_get_guest(unsigned int cid, const char *name)
 
 	if (cid > 0) {
 		guest = get_guest_by_cid(cid);
-		if (!guest && name) {
+		if (!guest && name)
 			guest = add_guest(cid, name);
-			if (guest)
-				find_pid_by_cid(guest);
-		}
 	}
 	return guest;
 }
@@ -355,7 +355,6 @@ struct trace_guest *trace_get_guest(unsigned int cid, const char *name)
 #define VM_CID_ID	"address='"
 static void read_guest_cid(char *name)
 {
-	struct trace_guest *guest;
 	char *cmd = NULL;
 	char line[512];
 	char *cid;
@@ -377,9 +376,7 @@ static void read_guest_cid(char *name)
 		cid_id = strtol(cid + strlen(VM_CID_ID), NULL, 10);
 		if ((cid_id == INT_MIN || cid_id == INT_MAX) && errno == ERANGE)
 			continue;
-		guest = add_guest(cid_id, name);
-		if (guest)
-			find_pid_by_cid(guest);
+		add_guest(cid_id, name);
 		break;
 	}
 
-- 
2.35.1