add ust_fork()
[ust.git] / libust / tracectl.c
index abd796203d19e0c0d098b6ea5f5302a77f1ad56a..9dfc8af6f6ad6ccb3b611cbb1136c552238046f0 100644 (file)
@@ -1,3 +1,20 @@
+/* Copyright (C) 2009  Pierre-Marc Fournier
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
 #define _GNU_SOURCE
 #include <stdio.h>
 #include <stdint.h>
 #include <fcntl.h>
 #include <poll.h>
 
+#include <urcu.h>
+
 #include "marker.h"
 #include "tracer.h"
 #include "localerr.h"
 #include "ustcomm.h"
 #include "relay.h" /* FIXME: remove */
+#include "marker-control.h"
 
 //#define USE_CLONE
 
@@ -88,8 +108,13 @@ void do_command(struct tracecmd *cmd)
 {
 }
 
-void receive_commands()
+/* This needs to be called whenever a new thread is created. It notifies
+ * liburcu of the new thread.
+ */
+
+void ust_register_thread(void)
 {
+       rcu_register_thread();
 }
 
 int fd_notif = -1;
@@ -146,7 +171,8 @@ void process_blocked_consumers(void)
                idx++;
        }
 
-       result = poll(fds, n_fds, 0);
+       while((result = poll(fds, n_fds, 0)) == -1 && errno == EINTR)
+               /* nothing */;
        if(result == -1) {
                PERROR("poll");
                return;
@@ -205,12 +231,11 @@ void *listener_main(void *p)
 {
        int result;
 
+       ust_register_thread();
+
        DBG("LISTENER");
 
        for(;;) {
-               uint32_t size;
-               struct sockaddr_un addr;
-               socklen_t addrlen = sizeof(addr);
                char trace_name[] = "auto";
                char trace_type[] = "ustrelay";
                char *recvbuf;
@@ -355,7 +380,6 @@ void *listener_main(void *p)
                                struct rchan *rchan = trace->channels[i].trans_channel_data;
                                struct rchan_buf *rbuf = rchan->buf;
                                struct ltt_channel_struct *ltt_channel = (struct ltt_channel_struct *)rchan->private_data;
-                               struct ltt_channel_buf_struct *ltt_buf = ltt_channel->buf;
 
                                if(!strcmp(trace->channels[i].channel_name, channel_name)) {
                                        char *reply;
@@ -500,9 +524,6 @@ void *listener_main(void *p)
                                if(!strcmp(trace->channels[i].channel_name, channel_name)) {
                                        struct rchan_buf *rbuf = rchan->buf;
                                        struct ltt_channel_buf_struct *lttbuf = trace->channels[i].buf;
-                                       char *reply;
-                                       long consumed_old=0;
-                                       int fd;
                                        struct blocked_consumer *bc;
 
                                        bc = (struct blocked_consumer *) malloc(sizeof(struct blocked_consumer));
@@ -598,7 +619,6 @@ void *listener_main(void *p)
                        char *channel_slash_name = nth_token(recvbuf, 1);
                        char channel_name[256]="";
                        char marker_name[256]="";
-                       struct marker_iter iter;
 
                        result = sscanf(channel_slash_name, "%255[^/]/%255s", channel_name, marker_name);
 
@@ -617,7 +637,6 @@ void *listener_main(void *p)
                        char *channel_slash_name = nth_token(recvbuf, 1);
                        char *marker_name;
                        char *channel_name;
-                       struct marker_iter iter;
 
                        result = sscanf(channel_slash_name, "%a[^/]/%as", &channel_name, &marker_name);
 
@@ -688,13 +707,11 @@ void *listener_main(void *p)
        }
 }
 
-static char listener_stack[16384];
-
 void create_listener(void)
 {
-       int result;
+#ifdef USE_CLONE
        static char listener_stack[16384];
-       //char *listener_stack = malloc(16384);
+#endif
 
 #ifdef USE_CLONE
        result = clone(listener_main, listener_stack+sizeof(listener_stack)-1, CLONE_FS | CLONE_FILES | CLONE_VM | CLONE_SIGHAND | CLONE_THREAD, NULL);
@@ -734,18 +751,22 @@ static int init_socket(void)
        return ustcomm_init_app(getpid(), &ustcomm_app);
 }
 
+/* FIXME: reenable this to delete socket file. */
+
+#if 0
 static void destroy_socket(void)
 {
-//     int result;
-//
-//     if(mysocketfile[0] == '\0')
-//             return;
-//
-//     result = unlink(mysocketfile);
-//     if(result == -1) {
-//             PERROR("unlink");
-//     }
+       int result;
+
+       if(mysocketfile[0] == '\0')
+               return;
+
+       result = unlink(mysocketfile);
+       if(result == -1) {
+               PERROR("unlink");
+       }
 }
+#endif
 
 static int init_signal_handler(void)
 {
@@ -783,22 +804,26 @@ static void auto_probe_connect(struct marker *m)
        int result;
 
        result = ltt_marker_connect(m->channel, m->name, "default");
-       if(result)
-               ERR("ltt_marker_connect");
+       if(result && result != -EEXIST)
+               ERR("ltt_marker_connect (marker = %s/%s, errno = %d)", m->channel, m->name, -result);
 
        DBG("just auto connected marker %s %s to probe default", m->channel, m->name);
 }
 
 static void __attribute__((constructor(101))) init0()
 {
+       /* Initialize RCU in case the constructor order is not good. */
+       urcu_init();
+
+       /* It is important to do this before events start to be generated. */
+       ust_register_thread();
+
        DBG("UST_AUTOPROBE constructor");
        if(getenv("UST_AUTOPROBE")) {
                marker_set_new_marker_cb(auto_probe_connect);
        }
 }
 
-static void fini(void);
-
 static void __attribute__((constructor(1000))) init()
 {
        int result;
@@ -895,3 +920,24 @@ static void __attribute__((destructor)) fini()
        destroy_socket();
 }
 #endif
+
+/* Notify ust that there was a fork. This needs to be called inside
+ * the new process, anytime a process whose memory is not shared with
+ * the parent is created. If this function is not called, the events
+ * of the new process will not be collected.
+ */
+
+void ust_fork(void)
+{
+       DBG("ust: forking");
+       ltt_trace_stop("auto");
+       ltt_trace_destroy("auto");
+       ltt_trace_alloc("auto");
+       ltt_trace_start("auto");
+       init_socket();
+       have_listener = 0;
+       create_listener();
+       ustcomm_request_consumer(getpid(), "metadata");
+       ustcomm_request_consumer(getpid(), "ust");
+}
+
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