From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:56487) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1STzGR-0008AL-7F for qemu-devel@nongnu.org; Mon, 14 May 2012 13:40:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1STzGP-0004FT-1L for qemu-devel@nongnu.org; Mon, 14 May 2012 13:40:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56440) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1STzGO-0004Es-OA for qemu-devel@nongnu.org; Mon, 14 May 2012 13:40:52 -0400 Date: Mon, 14 May 2012 14:40:58 -0300 From: Luiz Capitulino Message-ID: <20120514144058.2ffac223@doriath.home> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] [PATCH] qemu-ga: guest-shutdown: use only async-signal-safe functions List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel Cc: Eric Blake , mdroth@linux.vnet.ibm.com POSIX mandates[1] that a child process of a multi-thread program uses only async-signal-safe functions before exec(). We consider qemu-ga to be multi-thread, because it uses glib. However, qmp_guest_shutdown() uses functions that are not async-signal-safe. Fix it the following way: - fclose() -> reopen_fd_to_null() - execl() -> execle() - exit() -> _exit() - drop slog() usage (which is not safe) [1] http://pubs.opengroup.org/onlinepubs/009695399/functions/fork.html Signed-off-by: Luiz Capitulino --- qapi-schema-guest.json | 3 +-- qga/commands-posix.c | 17 +++++++---------- 2 files changed, 8 insertions(+), 12 deletions(-) diff --git a/qapi-schema-guest.json b/qapi-schema-guest.json index 1c949ff..8fd25be 100644 --- a/qapi-schema-guest.json +++ b/qapi-schema-guest.json @@ -126,8 +126,7 @@ # @guest-shutdown: # # Initiate guest-activated shutdown. Note: this is an asynchronous -# shutdown request, with no guaruntee of successful shutdown. Errors -# will be logged to guest's syslog. +# shutdown request, with no guaruntee of successful shutdown. # # @mode: #optional "halt", "powerdown" (default), or "reboot" # diff --git a/qga/commands-posix.c b/qga/commands-posix.c index 9a59276..f2c5e94 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -57,16 +57,13 @@ void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err) if (pid == 0) { /* child, start the shutdown */ setsid(); - fclose(stdin); - fclose(stdout); - fclose(stderr); - - ret = execl("/sbin/shutdown", "shutdown", shutdown_flag, "+0", - "hypervisor initiated shutdown", (char*)NULL); - if (ret) { - slog("guest-shutdown failed: %s", strerror(errno)); - } - exit(!!ret); + reopen_fd_to_null(0); + reopen_fd_to_null(1); + reopen_fd_to_null(2); + + ret = execle("/sbin/shutdown", "shutdown", shutdown_flag, "+0", + "hypervisor initiated shutdown", (char*)NULL, environ); + _exit(!!ret); } else if (pid < 0) { goto exit_err; } -- 1.7.9.2.384.g4a92a