[lttng-dev] [RFC PATCH 2/2] Add -ust to the name of UST threads of the application

[raphael.beamonte@gmail.com (Raphaël Beamonte)]

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Add the required functions to change the thread name of the UST
threads and add the -ust string at its end. This will help to
identify LTTng-UST processes when analyzing the trace of a process.

Signed-off-by: Raphaël Beamonte <raphael.beamonte at gmail.com>
---
 liblttng-ust/Makefile.am      |  1 +
 liblttng-ust/compat.h         | 35 +++++++++++++++++++++++++++++++++++
 liblttng-ust/lttng-ust-comm.c |  2 ++
 3 files changed, 38 insertions(+)

diff --git a/liblttng-ust/Makefile.am b/liblttng-ust/Makefile.am
index 876e9b5..8d78d63 100644
--- a/liblttng-ust/Makefile.am
+++ b/liblttng-ust/Makefile.am
@@ -13,6 +13,7 @@ liblttng_ust_tracepoint_la_SOURCES = \
 	error.h
 liblttng_ust_tracepoint_la_LIBADD = \
 	-lurcu-bp \
+	-lpthread \
 	$(top_builddir)/snprintf/libustsnprintf.la
 liblttng_ust_tracepoint_la_LDFLAGS = -no-undefined -version-info $(LTTNG_UST_LIBRARY_VERSION)
 liblttng_ust_tracepoint_la_CFLAGS = -DUST_COMPONENT="liblttng_ust_tracepoint" -fno-strict-aliasing
diff --git a/liblttng-ust/compat.h b/liblttng-ust/compat.h
index 43b2223..161b957 100644
--- a/liblttng-ust/compat.h
+++ b/liblttng-ust/compat.h
@@ -24,6 +24,7 @@
  */
 #ifdef __linux__
 
+#include <pthread.h>
 #include <sys/prctl.h>
 
 #define LTTNG_UST_PROCNAME_LEN 17
@@ -34,6 +35,23 @@ void lttng_ust_getprocname(char *name)
 	(void) prctl(PR_GET_NAME, (unsigned long) name, 0, 0, 0);
 }
 
+static inline
+void lttng_ust_setustprocname()
+{
+	char name[LTTNG_UST_PROCNAME_LEN];
+	int limit = LTTNG_UST_PROCNAME_LEN - 4;
+
+	lttng_ust_getprocname(name);
+
+	if (strlen(name) >= limit) {
+		name[limit] = 0;
+	}
+
+	sprintf(name, "%s%s", name, "-ust");
+
+	pthread_setname_np(pthread_self(), name);
+}
+
 #elif defined(__FreeBSD__)
 #include <stdlib.h>
 #include <string.h>
@@ -59,6 +77,23 @@ void lttng_ust_getprocname(char *name)
 		strncpy(name, bsd_name, LTTNG_UST_PROCNAME_LEN - 1);
 }
 
+static inline
+void lttng_ust_setustprocname()
+{
+	char name[LTTNG_UST_PROCNAME_LEN];
+	int limit = LTTNG_UST_PROCNAME_LEN - 4;
+
+	lttng_ust_getprocname(name);
+
+	if (strlen(name) >= limit) {
+		name[limit] = 0;
+	}
+
+	sprintf(name, "%s%s", name, "-ust");
+
+	pthread_set_name_np(pthread_self(), name);
+}
+
 #endif
 
 #include <errno.h>
diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index e00a22c..a85cb21 100644
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -1295,6 +1295,8 @@ void *ust_listener_thread(void *arg)
 	int sock, ret, prev_connect_failed = 0, has_waited = 0;
 	long timeout;
 
+	lttng_ust_setustprocname();
+
 	/* Restart trying to connect to the session daemon */
 restart:
 	if (prev_connect_failed) {
-- 
2.1.4