add get/set commands for daemon socket path

[ust.git] / libust / tracectl.c

diff --git a/libust/tracectl.c b/libust/tracectl.c
index 39756a55fec0e72602479593fce153408fc950d5..1b684445e63f1a2efa38bd59f0678f018adb6a9a 100644 (file)
--- a/libust/tracectl.c
+++ b/libust/tracectl.c
@@ -15,10 +15,16 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  */
 
+/* This file contains the implementation of the UST listener thread, which
+ * receives trace control commands. It also coordinates the initialization of
+ * libust.
+ */
+
 #define _GNU_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdint.h>
+#include <pthread.h>
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -48,6 +54,8 @@
  */
 s64 pidunique = -1LL;
 
+extern struct chan_info_struct chan_infos[];
+
 struct list_head blocked_consumers = LIST_HEAD_INIT(blocked_consumers);
 
 static struct ustcomm_app ustcomm_app;
@@ -456,18 +464,18 @@ static int do_cmd_get_subbuf_size(const char *recvbuf, struct ustcomm_source *sr
        return retval;
 }
 
-static unsigned int poweroftwo(unsigned int x)
-{
-    unsigned int power2 = 1;
-    unsigned int hardcoded = 2147483648u; /* FIX max 2^31 */
-
-    if (x < 2)
-        return 2;
-
-    while (power2 < x && power2 < hardcoded)
-        power2 *= 2;
+/* Return the power of two which is equal or higher to v */
 
-    return power2;
+static unsigned int pow2_higher_or_eq(unsigned int v)
+{
+       int hb = fls(v);
+       int hbm1 = hb-1;
+       int retval = 1<<(hb-1);
+
+       if(v-retval == 0)
+               return retval;
+       else
+               return retval<<1;
 }
 
 static int do_cmd_set_subbuf_size(const char *recvbuf, struct ustcomm_source *src)
@@ -491,9 +499,10 @@ static int do_cmd_set_subbuf_size(const char *recvbuf, struct ustcomm_source *sr
                goto end;
        }
 
-       power = poweroftwo(size);
+       power = pow2_higher_or_eq(size);
+       power = max_t(unsigned int, 2u, power);
        if (power != size)
-               WARN("using the next 2^n = %u\n", power);
+               WARN("using the next power of two for buffer size = %u\n", power);
 
        ltt_lock_traces();
        trace = _ltt_trace_find_setup(trace_name);
@@ -985,6 +994,25 @@ int process_client_cmd(char *recvbuf, struct ustcomm_source *src)
 
                free(reply);
        }
+       else if(nth_token_is(recvbuf, "get_sock_path", 0) == 1) {
+               char *reply = getenv("UST_DAEMON_SOCKET");
+               if(!reply) {
+                       asprintf(&reply, "%s/%s", SOCK_DIR, "ustd");
+                       result = ustcomm_send_reply(&ustcomm_app.server, reply, src);
+                       free(reply);
+               }
+               else {
+                       result = ustcomm_send_reply(&ustcomm_app.server, reply, src);
+               }
+               if(result)
+                       ERR("ustcomm_send_reply failed");
+       }
+       else if(nth_token_is(recvbuf, "set_sock_path", 0) == 1) {
+               char *sock_path = nth_token(recvbuf, 1);
+               result = setenv("UST_DAEMON_SOCKET", sock_path, 1);
+               if(result)
+                       ERR("cannot set UST_DAEMON_SOCKET environment variable");
+       }
        else {
                ERR("unable to parse message: %s", recvbuf);
        }
@@ -1030,18 +1058,40 @@ static pthread_t listener_thread;
 void create_listener(void)
 {
        int result;
+       sigset_t sig_all_blocked;
+       sigset_t orig_parent_mask;
 
        if(have_listener) {
                WARN("not creating listener because we already had one");
                return;
        }
 
+       /* A new thread created by pthread_create inherits the signal mask
+        * from the parent. To avoid any signal being received by the
+        * listener thread, we block all signals temporarily in the parent,
+        * while we create the listener thread.
+        */
+
+       sigfillset(&sig_all_blocked);
+
+       result = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask);
+       if(result) {
+               PERROR("pthread_sigmask: %s", strerror(result));
+       }
+
        result = pthread_create(&listener_thread, NULL, listener_main, NULL);
        if(result == -1) {
                PERROR("pthread_create");
        }
 
-       have_listener = 1;
+       /* Restore original signal mask in parent */
+       result = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL);
+       if(result) {
+               PERROR("pthread_sigmask: %s", strerror(result));
+       }
+       else {
+               have_listener = 1;
+       }
 }
 
 static int init_socket(void)
@@ -1091,6 +1141,11 @@ static void __attribute__((constructor)) init()
 {
        int result;
        char* autoprobe_val = NULL;
+       char* subbuffer_size_val = NULL;
+       char* subbuffer_count_val = NULL;
+       unsigned int subbuffer_size;
+       unsigned int subbuffer_count;
+       unsigned int power;
 
        /* Assign the pidunique, to be able to differentiate the processes with same
         * pid, (before and after an exec).
@@ -1174,6 +1229,23 @@ static void __attribute__((constructor)) init()
                }
        }
 
+       subbuffer_size_val = getenv("UST_SUBBUF_SIZE");
+       if(subbuffer_size_val) {
+               sscanf(subbuffer_size_val, "%u", &subbuffer_size);
+               power = pow2_higher_or_eq(subbuffer_size);
+               if(power != subbuffer_size)
+                       WARN("using the next power of two for buffer size = %u\n", power);
+               chan_infos[LTT_CHANNEL_UST].def_subbufsize = power;
+       }
+
+       subbuffer_count_val = getenv("UST_SUBBUF_NUM");
+       if(subbuffer_count_val) {
+               sscanf(subbuffer_count_val, "%u", &subbuffer_count);
+               if(subbuffer_count < 2)
+                       subbuffer_count = 2;
+               chan_infos[LTT_CHANNEL_UST].def_subbufcount = subbuffer_count;
+       }
+
        if(getenv("UST_TRACE")) {
                char trace_name[] = "auto";
                char trace_type[] = "ustrelay";
@@ -1240,7 +1312,6 @@ static void __attribute__((constructor)) init()
                inform_consumer_daemon(trace_name);
        }
 
-
        return;
 
        /* should decrementally destroy stuff if error */
@@ -1318,10 +1389,13 @@ int restarting_usleep(useconds_t usecs)
        return result;
 }
 
-static void stop_listener()
+static void stop_listener(void)
 {
        int result;
 
+       if(!have_listener)
+               return;
+
        result = pthread_cancel(listener_thread);
        if(result != 0) {
                ERR("pthread_cancel: %s", strerror(result));