[libvirt] [PATCHv2] virnetserver: handle sigaction correctly
POSIX says that sa_sigaction is only safe to use if sa_flags
includes SA_SIGINFO; conversely, sa_handler is only safe to
use when flags excludes that bit. Gnulib doesn't guarantee
an implementation of SA_SIGINFO, but does guarantee that
if SA_SIGINFO is undefined, we can safely define it to 0 as
long as we don't dereference the 2nd or 3rd argument of
any handler otherwise registered via sa_sigaction.
Based on a report by Wen Congyang.
* src/rpc/virnetserver.c (SA_SIGINFO): Stub for mingw.
(virNetServerSignalHandler): Avoid bogus dereference.
(virNetServerFatalSignal, virNetServerNew): Set flags properly.
---
v2: Simplify according to what gnulib gives us for mingw.
src/rpc/virnetserver.c | 28 ++++++++++++++++++++--------
1 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/src/rpc/virnetserver.c b/src/rpc/virnetserver.c
index 3965fc2..3f3989e 100644
--- a/src/rpc/virnetserver.c
+++ b/src/rpc/virnetserver.c
@@ -1,7 +1,7 @@
/*
* virnetserver.c: generic network RPC server
*
- * Copyright (C) 2006-2011 Red Hat, Inc.
+ * Copyright (C) 2006-2012 Red Hat, Inc.
* Copyright (C) 2006 Daniel P. Berrange
*
* This library is free software; you can redistribute it and/or
@@ -40,6 +40,10 @@
# include "virnetservermdns.h"
#endif
+#ifndef SA_SIGINFO
+# define SA_SIGINFO 0
+#endif
+
#define VIR_FROM_THIS VIR_FROM_RPC
#define virNetError(code, ...) \
virReportErrorHelper(VIR_FROM_THIS, code, __FILE__, \
@@ -270,8 +274,9 @@ error:
}
-static void virNetServerFatalSignal(int sig, siginfo_t *siginfo ATTRIBUTE_UNUSED,
- void *context ATTRIBUTE_UNUSED)
+static void
+virNetServerFatalSignal(int sig, siginfo_t *siginfo ATTRIBUTE_UNUSED,
+ void *context ATTRIBUTE_UNUSED)
{
struct sigaction sig_action;
int origerrno;
@@ -286,6 +291,7 @@ static void virNetServerFatalSignal(int sig, siginfo_t *siginfo
ATTRIBUTE_UNUSED
#ifdef SIGUSR2
if (sig != SIGUSR2) {
#endif
+ memset(&sig_action, 0, sizeof(sig_action));
sig_action.sa_handler = SIG_DFL;
sigaction(sig, &sig_action, NULL);
raise(sig);
@@ -363,6 +369,7 @@ virNetServerPtr virNetServerNew(size_t min_workers,
* debugging purposes or testing
*/
sig_action.sa_sigaction = virNetServerFatalSignal;
+ sig_action.sa_flags = SA_SIGINFO;
sigaction(SIGFPE, &sig_action, NULL);
sigaction(SIGSEGV, &sig_action, NULL);
sigaction(SIGILL, &sig_action, NULL);
@@ -420,17 +427,24 @@ static sig_atomic_t sigErrors = 0;
static int sigLastErrno = 0;
static int sigWrite = -1;
-static void virNetServerSignalHandler(int sig, siginfo_t * siginfo,
- void* context ATTRIBUTE_UNUSED)
+static void
+virNetServerSignalHandler(int sig, siginfo_t * siginfo ATTRIBUTE_UNUSED,
+ void* context ATTRIBUTE_UNUSED)
{
int origerrno;
int r;
+ siginfo_t tmp;
+
+ if (SA_SIGINFO)
+ tmp = *siginfo;
+ else
+ memset(&tmp, 0, sizeof(tmp));
/* set the sig num in the struct */
- siginfo->si_signo = sig;
+ tmp->si_signo = sig;
origerrno = errno;
- r = safewrite(sigWrite, siginfo, sizeof(*siginfo));
+ r = safewrite(sigWrite, &tmp, sizeof(tmp));
if (r == -1) {
sigErrors++;
sigLastErrno = errno;
@@ -533,9 +547,7 @@ int virNetServerAddSignalHandler(virNetServerPtr srv,
memset(&sig_action, 0, sizeof(sig_action));
sig_action.sa_sigaction = virNetServerSignalHandler;
-#ifdef SA_SIGINFO
sig_action.sa_flags = SA_SIGINFO;
-#endif
sigemptyset(&sig_action.sa_mask);
sigaction(signum, &sig_action, &sigdata->oldaction);
--
1.7.7.6