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authorPeter Maydell <peter.maydell@linaro.org>2013-02-20 15:21:09 +0000
committerBlue Swirl <blauwirbel@gmail.com>2013-02-23 16:11:19 +0000
commit6ab7e5465a4d6188e29398fb43a30dbab1015b75 (patch)
tree1e8bc48fc86c89b32a07f9379a40ed907d2a91dd /monitor.c
parentd1c36ba707637173b818652e51181370d51b6c58 (diff)
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Replace all setjmp()/longjmp() with sigsetjmp()/siglongjmp()
The setjmp() function doesn't specify whether signal masks are saved and restored; on Linux they are not, but on BSD (including MacOSX) they are. We want to have consistent behaviour across platforms, so we should always use "don't save/restore signal mask" (this is also generally going to be faster). This also works around a bug in MacOSX where the signal-restoration on longjmp() affects the signal mask for a completely different thread, not just the mask for the thread which did the longjmp. The most visible effect of this was that ctrl-C was ignored on MacOSX because the CPU thread did a longjmp which resulted in its signal mask being applied to every thread, so that all threads had SIGINT and SIGTERM blocked. The POSIX-sanctioned portable way to do a jump without affecting signal masks is to siglongjmp() to a sigjmp_buf which was created by calling sigsetjmp() with a zero savemask parameter, so change all uses of setjmp()/longjmp() accordingly. [Technically POSIX allows sigsetjmp(buf, 0) to save the signal mask; however the following siglongjmp() must not restore the signal mask, so the pair can be effectively considered as "sigjmp/longjmp which don't touch the mask".] For Windows we provide a trivial sigsetjmp/siglongjmp in terms of setjmp/longjmp -- this is OK because no user will ever pass a non-zero savemask. The setjmp() uses in tests/tcg/test-i386.c and tests/tcg/linux-test.c are left untouched because these are self-contained singlethreaded test programs intended to be run under QEMU's Linux emulation, so they have neither the portability nor the multithreading issues to deal with. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net> Tested-by: Stefan Weil <sw@weilnetz.de> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Diffstat (limited to 'monitor.c')
-rw-r--r--monitor.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/monitor.c b/monitor.c
index 6a0f2573f5..32a6e74fd9 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2740,7 +2740,7 @@ static const mon_cmd_t qmp_cmds[] = {
/*******************************************************************/
static const char *pch;
-static jmp_buf expr_env;
+static sigjmp_buf expr_env;
#define MD_TLONG 0
#define MD_I32 1
@@ -3135,7 +3135,7 @@ static const MonitorDef monitor_defs[] = {
static void expr_error(Monitor *mon, const char *msg)
{
monitor_printf(mon, "%s\n", msg);
- longjmp(expr_env, 1);
+ siglongjmp(expr_env, 1);
}
/* return 0 if OK, -1 if not found */
@@ -3345,7 +3345,7 @@ static int64_t expr_sum(Monitor *mon)
static int get_expr(Monitor *mon, int64_t *pval, const char **pp)
{
pch = *pp;
- if (setjmp(expr_env)) {
+ if (sigsetjmp(expr_env, 0)) {
*pp = pch;
return -1;
}