Implement field listing command

[lttng-ust.git] / liblttng-ust / lttng-ust-comm.c

diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c
index e3afe6af562cb8a22207ca90210b3450b8d2453d..76c8ee3da149ff49ecfe4633d7904927f1683de9 100644 (file)
--- a/liblttng-ust/lttng-ust-comm.c
+++ b/liblttng-ust/lttng-ust-comm.c
@@ -22,7 +22,6 @@
 #define _LGPL_SOURCE
 #include <sys/types.h>
 #include <sys/socket.h>
-#include <sys/prctl.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -46,6 +45,7 @@
 #include <usterr-signal-safe.h>
 #include "tracepoint-internal.h"
 #include "ltt-tracer-core.h"
+#include "compat.h"
 #include "../libringbuffer/tlsfixup.h"
 
 /*
@@ -160,7 +160,6 @@ static
 int register_app_to_sessiond(int socket)
 {
        ssize_t ret;
-       int prctl_ret;
        struct {
                uint32_t major;
                uint32_t minor;
@@ -179,11 +178,7 @@ int register_app_to_sessiond(int socket)
        reg_msg.uid = getuid();
        reg_msg.gid = getgid();
        reg_msg.bits_per_long = CAA_BITS_PER_LONG;
-       prctl_ret = prctl(PR_GET_NAME, (unsigned long) reg_msg.name, 0, 0, 0);
-       if (prctl_ret) {
-               ERR("Error executing prctl");
-               return -errno;
-       }
+       lttng_ust_getprocname(reg_msg.name);
 
        ret = ustcomm_send_unix_sock(socket, &reg_msg, sizeof(reg_msg));
        if (ret >= 0 && ret != sizeof(reg_msg))
@@ -325,14 +320,20 @@ end:
             || lum->cmd == LTTNG_UST_CHANNEL
             || lum->cmd == LTTNG_UST_METADATA)
                        && lur.ret_code == USTCOMM_OK) {
+               int sendret = 0;
+
                /* we also need to send the file descriptors. */
                ret = ustcomm_send_fds_unix_sock(sock,
                        &shm_fd, &shm_fd,
                        1, sizeof(int));
                if (ret < 0) {
                        perror("send shm_fd");
-                       goto error;
+                       sendret = ret;
                }
+               /*
+                * The sessiond expects 2 file descriptors, even upon
+                * error.
+                */
                ret = ustcomm_send_fds_unix_sock(sock,
                        &wait_fd, &wait_fd,
                        1, sizeof(int));
@@ -340,6 +341,10 @@ end:
                        perror("send wait_fd");
                        goto error;
                }
+               if (sendret) {
+                       ret = sendret;
+                       goto error;
+               }
        }
        /*
         * We still have the memory map reference, and the fds have been
@@ -827,6 +832,7 @@ int get_timeout(struct timespec *constructor_timeout)
 void __attribute__((constructor)) lttng_ust_init(void)
 {
        struct timespec constructor_timeout;
+       sigset_t sig_all_blocked, orig_parent_mask;
        int timeout_mode;
        int ret;
 
@@ -863,6 +869,18 @@ void __attribute__((constructor)) lttng_ust_init(void)
        if (ret) {
                ERR("Error setting up to local apps");
        }
+
+       /* 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);
+       ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask);
+       if (ret) {
+               PERROR("pthread_sigmask: %s", strerror(ret));
+       }
+
        ret = pthread_create(&local_apps.ust_listener, NULL,
                        ust_listener_thread, &local_apps);
 
@@ -873,6 +891,12 @@ void __attribute__((constructor)) lttng_ust_init(void)
                handle_register_done(&local_apps);
        }
 
+       /* Restore original signal mask in parent */
+       ret = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL);
+       if (ret) {
+               PERROR("pthread_sigmask: %s", strerror(ret));
+       }
+
        switch (timeout_mode) {
        case 1: /* timeout wait */
                do {