core: make gf_thread_create() easier to use

This patch creates a specific function to set the thread name using a
string format and a variable argument list, like printf().

This function is used to set the thread name from gf_thread_create(),
which now accepts a variable argument list to create the full name. It's
not necessary anymore to use a local array to build the name of the
thread. This is done automatically.

Change-Id: Idd8d01fd462c227359b96e98699f8c6d962dc17c
Updates: bz#1193929
Signed-off-by: Xavi Hernandez <xhernandez@redhat.com>

5 files changed, 105 insertions, 59 deletions

diff --git a/libglusterfs/src/common-utils.c b/libglusterfs/src/common-utils.c
index e16bb330a44..a49c84de5e1 100644
--- a/libglusterfs/src/common-utils.c
+++ b/libglusterfs/src/common-utils.c
@@ -3949,19 +3949,64 @@ error_return:
     return ret;
 }
 
+void
+gf_thread_set_vname(pthread_t thread, const char *name, va_list args)
+{
+    char thread_name[GF_THREAD_NAME_LIMIT];
+    int ret;
+
+    /* Initialize the thread name with the prefix (not NULL terminated). */
+    memcpy(thread_name, GF_THREAD_NAME_PREFIX,
+           sizeof(GF_THREAD_NAME_PREFIX) - 1);
+
+    ret = vsnprintf(thread_name + sizeof(GF_THREAD_NAME_PREFIX) - 1,
+                    sizeof(thread_name) - sizeof(GF_THREAD_NAME_PREFIX) + 1,
+                    name, args);
+    if (ret < 0) {
+        gf_msg(THIS->name, GF_LOG_WARNING, 0, LG_MSG_PTHREAD_NAMING_FAILED,
+               "Failed to compose thread name ('%s')", name);
+        return;
+    }
+
+    if (ret >= sizeof(thread_name)) {
+        gf_msg(THIS->name, GF_LOG_WARNING, 0, LG_MSG_PTHREAD_NAMING_FAILED,
+               "Thread name is too long. It has been truncated ('%s')",
+               thread_name);
+    }
+
+#ifdef GF_LINUX_HOST_OS
+    ret = pthread_setname_np(thread, thread_name);
+#elif defined(__NetBSD__)
+    ret = pthread_setname_np(thread, thread_name, NULL);
+#elif defined(__FreeBSD__)
+    pthread_set_name_np(thread, thread_name);
+    ret = 0;
+#else
+    ret = ENOSYS;
+#endif
+    if (ret != 0) {
+        gf_msg(THIS->name, GF_LOG_WARNING, ret, LG_MSG_PTHREAD_NAMING_FAILED,
+               "Could not set thread name: %s", thread_name);
+    }
+}
+
+void
+gf_thread_set_name(pthread_t thread, const char *name, ...)
+{
+    va_list args;
+
+    va_start(args, name);
+    gf_thread_set_vname(thread, name, args);
+    va_end(args);
+}
+
 int
-gf_thread_create(pthread_t *thread, const pthread_attr_t *attr,
-                 void *(*start_routine)(void *), void *arg, const char *name)
+gf_thread_vcreate(pthread_t *thread, const pthread_attr_t *attr,
+                  void *(*start_routine)(void *), void *arg, const char *name,
+                  va_list args)
 {
     sigset_t set, old;
     int ret;
-    char thread_name[GF_THREAD_NAMEMAX + GF_THREAD_NAME_PREFIX_LEN] = {
-        0,
-    };
-    /* Max name on Linux is 16 and on NetBSD is 32
-     * All Gluster threads have a set prefix of gluster and hence the limit
-     * of 9 on GF_THREAD_NAMEMAX including the null character.
-     */
 
     sigemptyset(&old);
     sigfillset(&set);
@@ -3975,20 +4020,12 @@ gf_thread_create(pthread_t *thread, const pthread_attr_t *attr,
     pthread_sigmask(SIG_BLOCK, &set, &old);
 
     ret = pthread_create(thread, attr, start_routine, arg);
-    snprintf(thread_name, sizeof(thread_name), "%s%s", GF_THREAD_NAME_PREFIX,
-             name);
-
-    if (0 == ret && name) {
-#ifdef GF_LINUX_HOST_OS
-        pthread_setname_np(*thread, thread_name);
-#elif defined(__NetBSD__)
-        pthread_setname_np(*thread, thread_name, NULL);
-#elif defined(__FreeBSD__)
-        pthread_set_name_np(*thread, thread_name);
-#else
-        gf_msg(THIS->name, GF_LOG_WARNING, 0, LG_MSG_PTHREAD_NAMING_FAILED,
-               "Could not set thread name: %s", thread_name);
-#endif
+    if (ret != 0) {
+        gf_msg(THIS->name, GF_LOG_ERROR, ret, LG_MSG_PTHREAD_FAILED,
+               "Thread creation failed");
+        ret = -1;
+    } else if (name != NULL) {
+        gf_thread_set_vname(*thread, name, args);
     }
 
     pthread_sigmask(SIG_SETMASK, &old, NULL);
@@ -3997,10 +4034,26 @@ gf_thread_create(pthread_t *thread, const pthread_attr_t *attr,
 }
 
 int
+gf_thread_create(pthread_t *thread, const pthread_attr_t *attr,
+                 void *(*start_routine)(void *), void *arg, const char *name,
+                 ...)
+{
+    va_list args;
+    int ret;
+
+    va_start(args, name);
+    ret = gf_thread_vcreate(thread, attr, start_routine, arg, name, args);
+    va_end(args);
+
+    return ret;
+}
+
+int
 gf_thread_create_detached(pthread_t *thread, void *(*start_routine)(void *),
-                          void *arg, const char *name)
+                          void *arg, const char *name, ...)
 {
     pthread_attr_t attr;
+    va_list args;
     int ret = -1;
 
     ret = pthread_attr_init(&attr);
@@ -4012,12 +4065,9 @@ gf_thread_create_detached(pthread_t *thread, void *(*start_routine)(void *),
 
     pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
 
-    ret = gf_thread_create(thread, &attr, start_routine, arg, name);
-    if (ret) {
-        gf_msg(THIS->name, GF_LOG_ERROR, ret, LG_MSG_PTHREAD_FAILED,
-               "Thread creation failed");
-        ret = -1;
-    }
+    va_start(args, name);
+    ret = gf_thread_vcreate(thread, &attr, start_routine, arg, name, args);
+    va_end(args);
 
     pthread_attr_destroy(&attr);
 
diff --git a/libglusterfs/src/event-epoll.c b/libglusterfs/src/event-epoll.c
index be8b204b7a7..dbf3faf6e6d 100644
--- a/libglusterfs/src/event-epoll.c
+++ b/libglusterfs/src/event-epoll.c
@@ -781,9 +781,6 @@ event_dispatch_epoll(struct event_pool *event_pool)
     int pollercount = 0;
     int ret = -1;
     struct event_thread_data *ev_data = NULL;
-    char thread_name[GF_THREAD_NAMEMAX] = {
-        0,
-    };
 
     /* Start the configured number of pollers */
     pthread_mutex_lock(&event_pool->mutex);
@@ -817,10 +814,8 @@ event_dispatch_epoll(struct event_pool *event_pool)
             ev_data->event_pool = event_pool;
             ev_data->event_index = i + 1;
 
-            snprintf(thread_name, sizeof(thread_name), "epoll%03hx",
-                     (i & 0x3ff));
             ret = gf_thread_create(&t_id, NULL, event_dispatch_epoll_worker,
-                                   ev_data, thread_name);
+                                   ev_data, "epoll%03hx", i & 0x3ff);
             if (!ret) {
                 event_pool->pollers[i] = t_id;
 
@@ -883,9 +878,6 @@ event_reconfigure_threads_epoll(struct event_pool *event_pool, int value)
     pthread_t t_id;
     int oldthreadcount;
     struct event_thread_data *ev_data = NULL;
-    char thread_name[GF_THREAD_NAMEMAX] = {
-        0,
-    };
 
     pthread_mutex_lock(&event_pool->mutex);
     {
@@ -925,11 +917,9 @@ event_reconfigure_threads_epoll(struct event_pool *event_pool, int value)
                     ev_data->event_pool = event_pool;
                     ev_data->event_index = i + 1;
 
-                    snprintf(thread_name, sizeof(thread_name), "epoll%03hx",
-                             (i & 0x3ff));
                     ret = gf_thread_create(&t_id, NULL,
                                            event_dispatch_epoll_worker, ev_data,
-                                           thread_name);
+                                           "epoll%03hx", i & 0x3ff);
                     if (ret) {
                         gf_msg("epoll", GF_LOG_WARNING, 0,
                                LG_MSG_START_EPOLL_THREAD_FAILED,
diff --git a/libglusterfs/src/glusterfs/common-utils.h b/libglusterfs/src/glusterfs/common-utils.h
index 89b38e02448..f03d2c1049a 100644
--- a/libglusterfs/src/glusterfs/common-utils.h
+++ b/libglusterfs/src/glusterfs/common-utils.h
@@ -147,9 +147,8 @@ trap(void);
 /* pthread related */
 /* as per the man page, thread-name should be at max 16 bytes */
 /* with prefix of 'glfs_' (5), we are left with 11 more bytes */
-#define GF_THREAD_NAMEMAX 11
+#define GF_THREAD_NAME_LIMIT 16
 #define GF_THREAD_NAME_PREFIX "glfs_"
-#define GF_THREAD_NAME_PREFIX_LEN 5
 
 /*
  * we could have initialized these as +ve values and treated
@@ -950,10 +949,24 @@ gf_set_timestamp(const char *src, const char *dest);
 
 int
 gf_thread_create(pthread_t *thread, const pthread_attr_t *attr,
-                 void *(*start_routine)(void *), void *arg, const char *name);
+                 void *(*start_routine)(void *), void *arg, const char *name,
+                 ...) __attribute__((__format__(__printf__, 5, 6)));
+
+int
+gf_thread_vcreate(pthread_t *thread, const pthread_attr_t *attr,
+                  void *(*start_routine)(void *), void *arg, const char *name,
+                  va_list args);
 int
 gf_thread_create_detached(pthread_t *thread, void *(*start_routine)(void *),
-                          void *arg, const char *name);
+                          void *arg, const char *name, ...)
+    __attribute__((__format__(__printf__, 4, 5)));
+
+void
+gf_thread_set_name(pthread_t thread, const char *name, ...)
+    __attribute__((__format__(__printf__, 2, 3)));
+
+void
+gf_thread_set_vname(pthread_t thread, const char *name, va_list args);
 gf_boolean_t
 gf_is_pid_running(int pid);
 gf_boolean_t
diff --git a/libglusterfs/src/libglusterfs.sym b/libglusterfs/src/libglusterfs.sym
index f0a92796187..e33d5cf14fc 100644
--- a/libglusterfs/src/libglusterfs.sym
+++ b/libglusterfs/src/libglusterfs.sym
@@ -710,7 +710,10 @@ gf_strTrim
 gf_strstr
 gf_thread_cleanup_xint
 gf_thread_create
+gf_thread_vcreate
 gf_thread_create_detached
+gf_thread_set_name
+gf_thread_set_vname
 gf_timer_call_after
 gf_timer_call_cancel
 gf_timer_registry_destroy
diff --git a/libglusterfs/src/syncop.c b/libglusterfs/src/syncop.c
index 6206d4cec7c..c05939a7915 100644
--- a/libglusterfs/src/syncop.c
+++ b/libglusterfs/src/syncop.c
@@ -695,9 +695,6 @@ syncenv_scale(struct syncenv *env)
     int scale = 0;
     int i = 0;
     int ret = 0;
-    char thread_name[GF_THREAD_NAMEMAX] = {
-        0,
-    };
 
     pthread_mutex_lock(&env->mutex);
     {
@@ -717,11 +714,9 @@ syncenv_scale(struct syncenv *env)
             }
 
             env->proc[i].env = env;
-            snprintf(thread_name, sizeof(thread_name), "sproc%03hx",
-                     (env->procs & 0x3ff));
             ret = gf_thread_create(&env->proc[i].processor, NULL,
                                    syncenv_processor, &env->proc[i],
-                                   thread_name);
+                                   "sproc%03hx", env->procs & 0x3ff);
             if (ret)
                 break;
             env->procs++;
@@ -783,9 +778,6 @@ syncenv_new(size_t stacksize, int procmin, int procmax)
     struct syncenv *newenv = NULL;
     int ret = 0;
     int i = 0;
-    char thread_name[GF_THREAD_NAMEMAX] = {
-        0,
-    };
 
     if (!procmin || procmin < 0)
         procmin = SYNCENV_PROC_MIN;
@@ -814,11 +806,9 @@ syncenv_new(size_t stacksize, int procmin, int procmax)
 
     for (i = 0; i < newenv->procmin; i++) {
         newenv->proc[i].env = newenv;
-        snprintf(thread_name, sizeof(thread_name), "%s%d", "sproc",
-                 (newenv->procs));
         ret = gf_thread_create(&newenv->proc[i].processor, NULL,
-                               syncenv_processor, &newenv->proc[i],
-                               thread_name);
+                               syncenv_processor, &newenv->proc[i], "sproc%d",
+                               newenv->procs);
         if (ret)
             break;
         newenv->procs++;