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 <den@openvz.org>
Signed-off-by: Yuri Pudgorodskiy <yur@virtuozzo.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

diff --git a/qga/commands.c b/qga/commands.c
index ced72d503e7ccfd026d6211d50f503aebfdfc840..68e8cfab189c64eea1753d5a7b8b03870373b3a1 100644 (file)
--- 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
index aa6a063446f8e6c1770791ff8bffb1e439264b11..068169fcbc0b4f258fa39cad0226f3705ab20eac 100644 (file)
--- 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;
 }