util: virExec: Dispatch all errors raised after fork

Any error message raised after the process has forked needs
to be followed by virDispatchError, otherwise we have no chance of
ever seeing it. This was selectively done for hook functions in the past,
but really applies to all post-fork errors.

src/util/util.c

@@ -283,7 +283,8 @@ static int virClearCapabilities(void)
     capng_clear(CAPNG_SELECT_BOTH);
 
     if ((ret = capng_apply(CAPNG_SELECT_BOTH)) < 0) {
-        VIR_ERROR(_("cannot clear process capabilities %d"), ret);
+        virUtilError(VIR_ERR_INTERNAL_ERROR,
+                     _("cannot clear process capabilities %d"), ret);
         return -1;
     }
 
@@ -310,7 +311,7 @@ static int virClearCapabilities(void)
    Even if *pid >= 0, if the return value from virFork() is < 0, it
    indicates a failure that occurred in the parent or child process
    after the fork. In this case, the child process should call
-   _exit(1) after doing any additional error reporting.
+   _exit(EXIT_FAILURE) after doing any additional error reporting.
 
  */
 int virFork(pid_t *pid) {
@@ -559,7 +560,7 @@ __virExec(const char *const*argv,
         /* The fork was sucessful, but after that there was an error
          * in the child (which was already logged).
         */
-        _exit(1);
+        goto fork_error;
     }
 
     openmax = sysconf (_SC_OPEN_MAX);
@@ -575,19 +576,19 @@ __virExec(const char *const*argv,
     if (dup2(infd >= 0 ? infd : null, STDIN_FILENO) < 0) {
         virReportSystemError(errno,
                              "%s", _("failed to setup stdin file handle"));
-        _exit(1);
+        goto fork_error;
     }
     if (childout > 0 &&
         dup2(childout, STDOUT_FILENO) < 0) {
         virReportSystemError(errno,
                              "%s", _("failed to setup stdout file handle"));
-        _exit(1);
+        goto fork_error;
     }
     if (childerr > 0 &&
         dup2(childerr, STDERR_FILENO) < 0) {
         virReportSystemError(errno,
                              "%s", _("failed to setup stderr file handle"));
-        _exit(1);
+        goto fork_error;
     }
 
     if (infd > 0)
@@ -605,20 +606,20 @@ __virExec(const char *const*argv,
         if (setsid() < 0) {
             virReportSystemError(errno,
                                  "%s", _("cannot become session leader"));
-            _exit(1);
+            goto fork_error;
         }
 
         if (chdir("/") < 0) {
             virReportSystemError(errno,
                                  "%s", _("cannot change to root directory: %s"));
-            _exit(1);
+            goto fork_error;
         }
 
         pid = fork();
         if (pid < 0) {
             virReportSystemError(errno,
                                  "%s", _("cannot fork child process"));
-            _exit(1);
+            goto fork_error;
         }
 
         if (pid > 0) {
@@ -629,7 +630,7 @@ __virExec(const char *const*argv,
                 virReportSystemError(errno,
                                      _("could not write pidfile %s for %d"),
                                      pidfile, pid);
-                _exit(1);
+                goto fork_error;
             }
             _exit(0);
         }
@@ -638,15 +639,14 @@ __virExec(const char *const*argv,
     if (hook)
         if ((hook)(data) != 0) {
             VIR_DEBUG0("Hook function failed.");
-            virDispatchError(NULL);
-            _exit(1);
+            goto fork_error;
         }
 
     /* The steps above may need todo something privileged, so
      * we delay clearing capabilities until the last minute */
     if ((flags & VIR_EXEC_CLEAR_CAPS) &&
         virClearCapabilities() < 0)
-        _exit(1);
+        goto fork_error;
 
     if (envp)
         execve(argv[0], (char **) argv, (char**)envp);
@@ -657,7 +657,9 @@ __virExec(const char *const*argv,
                          _("cannot execute binary %s"),
                          argv[0]);
 
-    _exit(1);
+ fork_error:
+    virDispatchError(NULL);
+    _exit(EXIT_FAILURE);
 
  cleanup:
     /* This is cleanup of parent process only - child