At 04/20/2012 11:45 AM, Eric Blake Wrote:
> 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,
Why siginfo has the attribute 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;
s/->/./
>
> 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);
ACK with nit fixed.
--
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