qga: handle possible SIGPIPE in guest-file-write

qemu-ga should not exit on guest-file-write to pipe without read end but proper error code should be returned. The behavior of the spawned process should be default thus SIGPIPE processing should be reset to default after fork() but before exec(). Signed-off-by: Denis V. Lunev <[email protected]> Signed-off-by: Yuri Pudgorodskiy <[email protected]> Reviewed-by: Michael Roth <[email protected]> Signed-off-by: Denis V. Lunev <[email protected]> Signed-off-by: Michael Roth <[email protected]>
zhijianli88 · Oct 19, 2015 · 4005b47 · 4005b47
1 parent d697e30
commit 4005b47
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Showing 2 changed files with 23 additions and 1 deletion.
diff --git a/qga/commands.c b/qga/commands.c
@@ -225,6 +225,22 @@ static void guest_exec_child_watch(GPid pid, gint status, gpointer data)
     g_spawn_close_pid(pid);
 }
 
+/** Reset ignored signals back to default. */
+static void guest_exec_task_setup(gpointer data)
+{
+#if !defined(G_OS_WIN32)
+    struct sigaction sigact;
+
+    memset(&sigact, 0, sizeof(struct sigaction));
+    sigact.sa_handler = SIG_DFL;
+
+    if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
+        slog("sigaction() failed to reset child process's SIGPIPE: %s",
+             strerror(errno));
+    }
+#endif
+}
+
 GuestExec *qmp_guest_exec(const char *path,
                        bool has_arg, strList *arg,
                        bool has_env, strList *env,
@@ -250,7 +266,7 @@ GuestExec *qmp_guest_exec(const char *path,
             G_SPAWN_SEARCH_PATH |
             G_SPAWN_DO_NOT_REAP_CHILD |
             G_SPAWN_STDOUT_TO_DEV_NULL | G_SPAWN_STDERR_TO_DEV_NULL,
-            NULL, NULL, &pid, NULL, NULL, NULL, &gerr);
+            guest_exec_task_setup, NULL, &pid, NULL, NULL, NULL, &gerr);
     if (!ret) {
         error_setg(err, QERR_QGA_COMMAND_FAILED, gerr->message);
         g_error_free(gerr);

diff --git a/qga/main.c b/qga/main.c
@@ -161,6 +161,12 @@ static gboolean register_signal_handlers(void)
         g_error("error configuring signal handler: %s", strerror(errno));
     }
 
+    sigact.sa_handler = SIG_IGN;
+    if (sigaction(SIGPIPE, &sigact, NULL) != 0) {
+        g_error("error configuring SIGPIPE signal handler: %s",
+                strerror(errno));
+    }
+
     return true;
 }