xemu/include/sysemu
Peter Maydell 6ab7e5465a 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>
2013-02-23 16:11:19 +00:00
..
arch_init.h softmmu: move include files to include/sysemu/ 2012-12-19 08:32:45 +01:00
balloon.h softmmu: move include files to include/sysemu/ 2012-12-19 08:32:45 +01:00
blockdev.h softmmu: move include files to include/sysemu/ 2012-12-19 08:32:45 +01:00
cpus.h cpus.c: Drop unnecessary set_cpu_log() 2013-02-16 10:45:19 +00:00
device_tree.h softmmu: move include files to include/sysemu/ 2012-12-19 08:32:45 +01:00
dma.h softmmu: move include files to include/sysemu/ 2012-12-19 08:32:45 +01:00
dump.h softmmu: move include files to include/sysemu/ 2012-12-19 08:32:45 +01:00
kvm.h accel: change {xen, kvm, tcg, qtest}_allowed from int to bool 2013-02-01 15:08:02 -06:00
memory_mapping.h softmmu: move include files to include/sysemu/ 2012-12-19 08:32:45 +01:00
os-posix.h softmmu: move include files to include/sysemu/ 2012-12-19 08:32:45 +01:00
os-win32.h Replace all setjmp()/longjmp() with sigsetjmp()/siglongjmp() 2013-02-23 16:11:19 +00:00
qtest.h accel: change {xen, kvm, tcg, qtest}_allowed from int to bool 2013-02-01 15:08:02 -06:00
seccomp.h softmmu: move include files to include/sysemu/ 2012-12-19 08:32:45 +01:00
sysemu.h ui: add basic GTK gui (v5) 2013-02-21 16:34:48 -06:00
xen-mapcache.h softmmu: move include files to include/sysemu/ 2012-12-19 08:32:45 +01:00