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Enable stack overflow recovery on Android

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* src/sysdep.c (handle_sigsegv): Return after restoring the
original signal handler, which should proceed to call debuggerd
to generate a tombstone.
(init_sigsegv): Save the original signal handler on Android, to
be restored after a signal is received.
(init_signals): Call init_sigsegv on Android.
This commit is contained in:
Po Lu 2024-03-09 16:12:40 +08:00
parent a4473afefe
commit 5d9a8c3704
1 changed files with 13 additions and 12 deletions
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25
src/sysdep.c
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@ -1853,11 +1853,7 @@ init_sigbus (void)
#endif
/* This does not work on Android and interferes with the system
tombstone generation. */
#if defined HAVE_STACK_OVERFLOW_HANDLING && !defined WINDOWSNT \
&& (!defined HAVE_ANDROID || defined ANDROID_STUBIFY)
#if defined HAVE_STACK_OVERFLOW_HANDLING && !defined WINDOWSNT
/* Alternate stack used by SIGSEGV handler below. */
@ -1921,6 +1917,8 @@ stack_overflow (siginfo_t *siginfo)
return 0 <= top - addr && top - addr < (bot - top) >> LG_STACK_HEURISTIC;
}
/* Signal handler for SIGSEGV before our new handler was installed. */
static struct sigaction old_sigsegv_handler;
/* Attempt to recover from SIGSEGV caused by C stack overflow. */
@ -1939,6 +1937,15 @@ handle_sigsegv (int sig, siginfo_t *siginfo, void *arg)
if (!fatal && stack_overflow (siginfo))
siglongjmp (return_to_command_loop, 1);
#if defined HAVE_ANDROID && !defined ANDROID_STUBIFY
/* Tombstones (crash reports with stack traces) won't be generated on
Android unless the original SIGSEGV handler is installed and the
signal is resent, such as by returning from the first signal
handler called. */
sigaction (SIGSEGV, &old_sigsegv_handler, NULL);
return;
#endif /* HAVE_ANDROID && ANDROID_STUBIFY */
/* Otherwise we can't do anything with this. */
deliver_fatal_thread_signal (sig);
}
@ -1961,7 +1968,7 @@ init_sigsegv (void)
sigfillset (&sa.sa_mask);
sa.sa_sigaction = handle_sigsegv;
sa.sa_flags = SA_SIGINFO | SA_ONSTACK | emacs_sigaction_flags ();
if (sigaction (SIGSEGV, &sa, NULL) < 0)
if (sigaction (SIGSEGV, &sa, &old_sigsegv_handler) < 0)
return 0;
return 1;
@ -1969,16 +1976,12 @@ init_sigsegv (void)
#else /* not HAVE_STACK_OVERFLOW_HANDLING or WINDOWSNT */
#if !defined HAVE_ANDROID || defined ANDROID_STUBIFY
static bool
init_sigsegv (void)
{
return 0;
}
#endif
#endif /* HAVE_STACK_OVERFLOW_HANDLING && !WINDOWSNT */
static void
@ -2125,10 +2128,8 @@ init_signals (void)
#endif
sigaction (SIGBUS, &thread_fatal_action, 0);
#endif
#if !defined HAVE_ANDROID || defined ANDROID_STUBIFY
if (!init_sigsegv ())
sigaction (SIGSEGV, &thread_fatal_action, 0);
#endif
#ifdef SIGSYS
sigaction (SIGSYS, &thread_fatal_action, 0);
#endif