From 7198056520faa3fe868d71f25a7600f9b94d342d Mon Sep 17 00:00:00 2001 Message-Id: <7198056520faa3fe868d71f25a7600f9b94d342d.1342518105.git.minovotn@redhat.com> In-Reply-To: <27a73856ecc481c66c7afac8171f753887f32e31.1342518105.git.minovotn@redhat.com> References: <27a73856ecc481c66c7afac8171f753887f32e31.1342518105.git.minovotn@redhat.com> From: Luiz Capitulino Date: Tue, 5 Jun 2012 14:58:45 +0200 Subject: [PATCH 36/41] qemu-ga: guest-shutdown: use only async-signal-safe functions RH-Author: Luiz Capitulino Message-id: <1338908331-15633-31-git-send-email-lcapitulino@redhat.com> Patchwork-id: 39927 O-Subject: [PATCH RHEL6.4 qemu-kvm 30/36] qemu-ga: guest-shutdown: use only async-signal-safe functions Bugzilla: 827612 RH-Acked-by: Paolo Bonzini RH-Acked-by: Juan Quintela RH-Acked-by: Laszlo Ersek 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 Reviewed-by: Eric Blake Signed-off-by: Michael Roth (cherry picked from commit 3674838cd05268954bb6473239cd7f700a79bf0f) Signed-off-by: Luiz Capitulino --- qapi-schema-guest.json | 3 +-- qga/commands-posix.c | 19 ++++++++----------- 2 files changed, 9 insertions(+), 13 deletions(-) Signed-off-by: Michal Novotny --- qapi-schema-guest.json | 3 +-- qga/commands-posix.c | 19 ++++++++----------- 2 files changed, 9 insertions(+), 13 deletions(-) diff --git a/qapi-schema-guest.json b/qapi-schema-guest.json index 7c6cb21..d4055d2 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 guarantee of successful shutdown. # # @mode: #optional "halt", "powerdown" (default), or "reboot" # diff --git a/qga/commands-posix.c b/qga/commands-posix.c index 1cd7cf0..e351475 100644 --- a/qga/commands-posix.c +++ b/qga/commands-posix.c @@ -42,8 +42,8 @@ void qmp_guest_shutdown(bool has_mode, const char *mode, Error **err) { const char *shutdown_flag; - int ret, status; pid_t rpid, pid; + int status; slog("guest-shutdown called, mode: %s", mode); if (!has_mode || strcmp(mode, "powerdown") == 0) { @@ -62,16 +62,13 @@ 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); + + execle("/sbin/shutdown", "shutdown", shutdown_flag, "+0", + "hypervisor initiated shutdown", (char*)NULL, environ); + _exit(EXIT_FAILURE); } else if (pid < 0) { goto exit_err; } -- 1.7.10.4