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libunwind-eh_elf/tests/Gtest-resume-sig.c
Dave Watson 29483327be x86_64: Use sigprocmask from signal frames
Currently setcontext for x86_64 restores the signal mask, even
though it is never saved anywhere.  This means the signal mask
is often garbage after an unw_resume.

(changed in commit f8a15e9679)

It looks like this was a fix for the Gtest-resume-sig function -
testing if signal masks are restored across signal frames.  The
root issue looks like that x86_64 only uses sigreturn for the exact
signal frame, and not for any decedant frames as well (as i64 does).

Instead, modify Gresume to use sigreturn if *any* frame on the stack
is a signal frame, so that we correct fixup the signal mask and any
sigaltstacks.  The sigreturn os-specific functions are changed slightly
to copy in the saved ucontext structure if we are jumping farther
up the stack.

This should fix sigprocmask reported issues such as
https://github.com/dropbox/pyston/blob/master/libunwind_patches/0002-pyston-stop-x86_64-setcontext-restoring-uninitialize.patch

Tests pass on freebsd, linux
2017-01-13 08:28:22 -08:00

192 lines
4.6 KiB
C

/* libunwind - a platform-independent unwind library
Copyright (C) 2003-2004 Hewlett-Packard Co
Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/* Verify that unw_resume() restores the signal mask at proper time. */
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "compiler.h"
#include <libunwind.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#ifdef HAVE_IA64INTRIN_H
# include <ia64intrin.h>
#endif
#define panic(args...) \
do { fprintf (stderr, args); ++nerrors; } while (0)
int verbose;
int nerrors;
int got_usr1, got_usr2;
char *sigusr1_sp;
uintptr_t
get_bsp (void)
{
#if UNW_TARGET_IA64
# ifdef __INTEL_COMPILER
return __getReg (_IA64_REG_AR_BSP);
# else
return (uintptr_t) __builtin_ia64_bsp ();
# endif
#else
return 0;
#endif
}
#ifdef TEST_WITH_SIGINFO
void
handler (int sig,
siginfo_t *si UNUSED,
void *ucontext UNUSED)
#else
void
handler (int sig)
#endif
{
unw_word_t ip;
sigset_t mask;
unw_context_t uc;
unw_cursor_t c;
char foo;
int ret;
#if UNW_TARGET_IA64
if (verbose)
printf ("bsp = %llx\n", (unsigned long long) get_bsp ());
#endif
if (verbose)
printf ("got signal %d\n", sig);
if (sig == SIGUSR1)
{
++got_usr1;
sigusr1_sp = &foo;
sigemptyset (&mask);
sigaddset (&mask, SIGUSR2);
sigprocmask (SIG_BLOCK, &mask, NULL);
kill (getpid (), SIGUSR2); /* pend SIGUSR2 */
signal (SIGUSR1, SIG_IGN);
if ((ret = unw_getcontext (&uc)) < 0)
panic ("unw_getcontext() failed: ret=%d\n", ret);
if ((ret = unw_init_local (&c, &uc)) < 0)
panic ("unw_init_local() failed: ret=%d\n", ret);
if ((ret = unw_step (&c)) < 0) /* step to signal trampoline */
panic ("unw_step(1) failed: ret=%d\n", ret);
if ((ret = unw_step (&c)) < 0) /* step to kill() */
panic ("unw_step(2) failed: ret=%d\n", ret);
#if defined(UNW_TARGET_TILEGX)
if ((ret = unw_step (&c)) < 0) /* step to signal trampoline */
panic ("unw_step(2) failed: ret=%d\n", ret);
#endif
if ((ret = unw_get_reg (&c, UNW_REG_IP, &ip)) < 0)
panic ("unw_get_reg(IP) failed: ret=%d\n", ret);
if (verbose)
printf ("resuming at 0x%lx, with SIGUSR2 pending\n",
(unsigned long) ip);
unw_resume (&c);
}
else if (sig == SIGUSR2)
{
++got_usr2;
if (got_usr1)
{
if (verbose)
printf ("OK: stack still at %p\n", &foo);
}
signal (SIGUSR2, SIG_IGN);
}
else
panic ("Got unexpected signal %d\n", sig);
}
int
main (int argc, char **argv UNUSED)
{
struct sigaction sa;
float d = 1.0;
int n = 0;
if (argc > 1)
verbose = 1;
memset (&sa, 0, sizeof(sa));
#ifdef TEST_WITH_SIGINFO
sa.sa_sigaction = handler;
sa.sa_flags = SA_SIGINFO;
#else
sa.sa_handler = handler;
#endif
if (sigaction (SIGUSR1, &sa, NULL) != 0 ||
sigaction (SIGUSR2, &sa, NULL) != 0)
{
fprintf (stderr, "sigaction() failed: %s\n", strerror (errno));
return -1;
}
/* Use the FPU a bit; otherwise we get spurious errors should the
signal handler need to use the FPU for any reason. This seems to
happen on x86-64. */
while (d > 0.0)
{
d /= 2.0;
++n;
}
if (n > 9999)
return -1; /* can't happen, but don't tell the compiler... */
if (verbose)
printf ("sending SIGUSR1\n");
kill (getpid (), SIGUSR1);
if (!got_usr2)
panic ("failed to get SIGUSR2\n");
if (nerrors)
{
fprintf (stderr, "FAILURE: detected %d errors\n", nerrors);
exit (-1);
}
if (verbose)
printf ("SUCCESS\n");
return 0;
}