Merged revisions 240499-240500 via svnmerge from

https://origsvn.digium.com/svn/asterisk/trunk

........
  r240499 | tilghman | 2010-01-15 15:40:14 -0600 (Fri, 15 Jan 2010) | 9 lines

  The previous attempt at using a pipe to guarantee astcanary shutdown did not work.
  We're revisiting the previous patch, albeit with a method that overcomes the
  prior criticism that it was not POSIX-compliant.
  (closes issue #16602)
   Reported by: frawd
   Patches:
         20100114__issue16602.diff.txt uploaded by tilghman (license 14)
   Tested by: frawd
........
  r240500 | tilghman | 2010-01-15 15:42:36 -0600 (Fri, 15 Jan 2010) | 2 lines

  Oops, missed an include
........

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.0@240501 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/main/asterisk.c b/main/asterisk.c
index 74a19bb75c4b1dc2fc96297087dfd3c50ab01399..11046f4c6da34dc9a5d1071a3de181014368ce78 100644 (file)
--- a/main/asterisk.c
+++ b/main/asterisk.c
@@ -261,7 +261,6 @@ static int restartnow;
 static pthread_t consolethread = AST_PTHREADT_NULL;
 static int canary_pid = 0;
 static char canary_filename[128];
-static int canary_pipe = -1;
 
 static char randompool[256];
 
@@ -3299,15 +3298,6 @@ int main(int argc, char *argv[])
 
        /* Spawning of astcanary must happen AFTER the call to daemon(3) */
        if (isroot && ast_opt_high_priority) {
-               int cpipe[2];
-
-               /* PIPE signal ensures that astcanary dies when Asterisk dies */
-               if (pipe(cpipe)) {
-                       fprintf(stderr, "Unable to open pipe for canary process: %s\n", strerror(errno));
-                       exit(1);
-               }
-               canary_pipe = cpipe[0];
-
                snprintf(canary_filename, sizeof(canary_filename), "%s/alt.asterisk.canary.tweet.tweet.tweet", ast_config_AST_RUN_DIR);
 
                /* Don't let the canary child kill Asterisk, if it dies immediately */
@@ -3315,20 +3305,19 @@ int main(int argc, char *argv[])
 
                canary_pid = fork();
                if (canary_pid == 0) {
-                       char canary_binary[128], *lastslash;
+                       char canary_binary[128], *lastslash, ppid[12];
                        int fd;
 
                        /* Reset signal handler */
                        signal(SIGCHLD, SIG_DFL);
                        signal(SIGPIPE, SIG_DFL);
 
-                       dup2(cpipe[1], 0);
-                       close(cpipe[1]);
                        for (fd = 1; fd < 100; fd++) {
                                close(fd);
                        }
+                       snprintf(ppid, sizeof(ppid), "%d", (int) getpid());
 
-                       execlp("astcanary", "astcanary", canary_filename, (char *)NULL);
+                       execlp("astcanary", "astcanary", canary_filename, ppid, (char *)NULL);
 
                        /* If not found, try the same path as used to execute asterisk */
                        ast_copy_string(canary_binary, argv[0], sizeof(canary_binary));
@@ -3341,12 +3330,11 @@ int main(int argc, char *argv[])
                        _exit(1);
                } else if (canary_pid > 0) {
                        pthread_t dont_care;
-                       close(cpipe[1]);
                        ast_pthread_create_detached(&dont_care, NULL, canary_thread, NULL);
                }
 
                /* Kill the canary when we exit */
-               atexit(canary_exit);
+               ast_register_atexit(canary_exit);
        }
 
        ast_event_init();

diff --git a/utils/astcanary.c b/utils/astcanary.c
index 68557beaaf0f89ac7bf211d4ff90263a15e12426..a48df720fd0ccb7ad5474cf40015802fa0d0d065 100644 (file)
--- a/utils/astcanary.c
+++ b/utils/astcanary.c
@@ -25,6 +25,7 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
+#include <stdio.h>
 
 /*!\brief
  * At one time, canaries were carried along with coal miners down
@@ -87,9 +88,25 @@ const char explanation[] =
 int main(int argc, char *argv[])
 {
        int fd;
+       pid_t parent;
+
+       if (argc < 3) {
+               fprintf(stderr, "Usage: %s <monitor-filename> <ppid>\n", argv[0]);
+               exit(1);
+       }
+
        /* Run at normal priority */
        setpriority(PRIO_PROCESS, 0, 0);
-       for (;;) {
+
+       /*!\note
+        * See http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#tag_03_265
+        * for a justification of this approach.  The PPID after the creator dies in Linux and
+        * most other Unix-like systems will be 1, but this is not strictly the case.  The POSIX
+        * specification allows it to be an implementation-defined system process.  However, it
+        * most certainly will not be the original parent PID, which makes the following code
+        * POSIX-compliant.
+        */
+       for (parent = atoi(argv[2]); parent == getppid() ;) {
                /* Update the modification times (checked from Asterisk) */
                if (utime(argv[1], NULL)) {
                        /* Recreate the file if it doesn't exist */
@@ -108,7 +125,7 @@ int main(int argc, char *argv[])
                sleep(5);
        }
 
-       /* Never reached */
+       /* Exit when the parent dies */
        return 0;
 }