Fix: combined tracing of lttng-ust 2.12/2.13 generates corrupted traces

[lttng-ust.git] / src / lib / lttng-ust / lttng-ust-comm.c

diff --git a/src/lib/lttng-ust/lttng-ust-comm.c b/src/lib/lttng-ust/lttng-ust-comm.c
index f180c3bc8277874ddd673954b1e3bf8467b7e95a..b1c35480e88c10f2c316d245256f00f52838f829 100644 (file)
--- a/src/lib/lttng-ust/lttng-ust-comm.c
+++ b/src/lib/lttng-ust/lttng-ust-comm.c
@@ -259,7 +259,7 @@ struct sock_info {
        int statedump_pending;
        int initial_statedump_done;
        /* Keep procname for statedump */
-       char procname[LTTNG_UST_ABI_PROCNAME_LEN];
+       char procname[LTTNG_UST_CONTEXT_PROCNAME_LEN];
 };
 
 /* Socket from app (connect) to session daemon (listen) for communication */
@@ -482,7 +482,7 @@ int setup_global_apps(void)
        }
 
        global_apps.allowed = 1;
-       lttng_pthread_getname_np(global_apps.procname, LTTNG_UST_ABI_PROCNAME_LEN);
+       lttng_pthread_getname_np(global_apps.procname, LTTNG_UST_CONTEXT_PROCNAME_LEN);
 error:
        return ret;
 }
@@ -528,7 +528,7 @@ int setup_local_apps(void)
                goto end;
        }
 
-       lttng_pthread_getname_np(local_apps.procname, LTTNG_UST_ABI_PROCNAME_LEN);
+       lttng_pthread_getname_np(local_apps.procname, LTTNG_UST_CONTEXT_PROCNAME_LEN);
 end:
        return ret;
 }
@@ -620,7 +620,8 @@ void get_allow_blocking(void)
 }
 
 static
-int register_to_sessiond(int socket, enum lttng_ust_ctl_socket_type type)
+int register_to_sessiond(int socket, enum lttng_ust_ctl_socket_type type,
+               const char *procname)
 {
        return ustcomm_send_reg_msg(socket,
                type,
@@ -629,7 +630,8 @@ int register_to_sessiond(int socket, enum lttng_ust_ctl_socket_type type)
                lttng_ust_rb_alignof(uint16_t) * CHAR_BIT,
                lttng_ust_rb_alignof(uint32_t) * CHAR_BIT,
                lttng_ust_rb_alignof(uint64_t) * CHAR_BIT,
-               lttng_ust_rb_alignof(unsigned long) * CHAR_BIT);
+               lttng_ust_rb_alignof(unsigned long) * CHAR_BIT,
+               procname);
 }
 
 static
@@ -1911,7 +1913,8 @@ restart:
                sock_info->root_handle = ret;
        }
 
-       ret = register_to_sessiond(sock_info->socket, LTTNG_UST_CTL_SOCKET_CMD);
+       ret = register_to_sessiond(sock_info->socket, LTTNG_UST_CTL_SOCKET_CMD,
+               sock_info->procname);
        if (ret < 0) {
                ERR("Error registering to %s ust cmd socket",
                        sock_info->name);
@@ -2004,7 +2007,7 @@ restart:
        }
 
        ret = register_to_sessiond(sock_info->notify_socket,
-                       LTTNG_UST_CTL_SOCKET_NOTIFY);
+                       LTTNG_UST_CTL_SOCKET_NOTIFY, sock_info->procname);
        if (ret < 0) {
                ERR("Error registering to %s ust notify socket",
                        sock_info->name);
@@ -2122,6 +2125,10 @@ void lttng_ust_check_soname_0(void)
  * Expose a canary symbol of the previous ABI to ensure we catch uses of a
  * liblttng-ust.so.0 dlopen'd after .so.1 has been loaded. Use a different
  * symbol than the detection code to ensure we don't detect ourself.
+ *
+ * This scheme will only work on systems where the global symbol table has
+ * priority when resolving the symbols of a dlopened shared object, which is
+ * the case on Linux but not on FreeBSD.
  */
 void init_usterr(void);
 void init_usterr(void)
@@ -2176,7 +2183,7 @@ void lttng_ust_ctor(void)
         * this library so it never becomes zero, thus never gets unloaded from the
         * address space of the process. Since we are already running in the
         * constructor of the LTTNG_UST_LIB_SONAME library, calling dlopen will
-        * simply increment the refcount and no additionnal work is needed by the
+        * simply increment the refcount and no additional work is needed by the
         * dynamic loader as the shared library is already loaded in the address
         * space. As a safe guard, we use the RTLD_NODELETE flag to prevent
         * unloading of the UST library if its refcount becomes zero (which should
@@ -2513,7 +2520,7 @@ void lttng_ust_after_fork_parent(sigset_t *restore_sigset)
                return;
        DBG("process %d", getpid());
        lttng_ust_urcu_after_fork_parent();
-       /* Release mutexes and reenable signals */
+       /* Release mutexes and re-enable signals */
        ust_after_fork_common(restore_sigset);
 }
 
@@ -2540,7 +2547,7 @@ void lttng_ust_after_fork_child(sigset_t *restore_sigset)
        /* Release urcu mutexes */
        lttng_ust_urcu_after_fork_child();
        lttng_ust_cleanup(0);
-       /* Release mutexes and reenable signals */
+       /* Release mutexes and re-enable signals */
        ust_after_fork_common(restore_sigset);
        lttng_ust_ctor();
 }