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authorRichard Henderson <richard.henderson@linaro.org>2023-09-30 12:05:11 -0700
committerRichard Henderson <richard.henderson@linaro.org>2023-10-18 16:25:06 -0700
commit38ee0a7dfb4b15407678df26448e4a18fd9a51d4 (patch)
tree5e7efbde27a86f40b10919cdf43f057b47db941c /linux-user/signal.c
parent4a6ebc19a7e2d013a0e2ca79452ea733b1d5b686 (diff)
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linux-user: Remap guest SIGABRT
Distinguish host SIGABRT from guest SIGABRT by mapping the guest signal onto one of the host RT signals. This prevents a cycle by which a host assertion failure is caught and handled by host_signal_handler, queued for the guest, and then we attempt to continue past the host abort. What happens next depends on the host libc, but is neither good nor helpful. Acked-by: Helge Deller <deller@gmx.de> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'linux-user/signal.c')
-rw-r--r--linux-user/signal.c42
1 files changed, 35 insertions, 7 deletions
diff --git a/linux-user/signal.c b/linux-user/signal.c
index b67077f..3b8efec 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -522,8 +522,21 @@ static void signal_table_init(void)
* multiplexed over a single host signal.
* Attempts for configure "missing" signals via sigaction will be
* silently ignored.
+ *
+ * Remap the target SIGABRT, so that we can distinguish host abort
+ * from guest abort. When the guest registers a signal handler or
+ * calls raise(SIGABRT), the host will raise SIG_RTn. If the guest
+ * arrives at dump_core_and_abort(), we will map back to host SIGABRT
+ * so that the parent (native or emulated) sees the correct signal.
+ * Finally, also map host to guest SIGABRT so that the emulated
+ * parent sees the correct mapping from wait status.
*/
- for (hsig = SIGRTMIN; hsig <= SIGRTMAX; hsig++) {
+
+ hsig = SIGRTMIN;
+ host_to_target_signal_table[SIGABRT] = 0;
+ host_to_target_signal_table[hsig++] = TARGET_SIGABRT;
+
+ for (; hsig <= SIGRTMAX; hsig++) {
tsig = hsig - SIGRTMIN + TARGET_SIGRTMIN;
if (tsig <= TARGET_NSIG) {
host_to_target_signal_table[hsig] = tsig;
@@ -539,6 +552,8 @@ static void signal_table_init(void)
}
}
+ host_to_target_signal_table[SIGABRT] = TARGET_SIGABRT;
+
/* Map everything else out-of-bounds. */
for (hsig = 1; hsig < _NSIG; hsig++) {
if (host_to_target_signal_table[hsig] == 0) {
@@ -582,13 +597,21 @@ void signal_init(void)
int hsig = target_to_host_signal(tsig);
abi_ptr thand = TARGET_SIG_IGN;
- if (hsig < _NSIG) {
- struct sigaction *iact = core_dump_signal(tsig) ? &act : NULL;
+ if (hsig >= _NSIG) {
+ continue;
+ }
+ /* As we force remap SIGABRT, cannot probe and install in one step. */
+ if (tsig == TARGET_SIGABRT) {
+ sigaction(SIGABRT, NULL, &oact);
+ sigaction(hsig, &act, NULL);
+ } else {
+ struct sigaction *iact = core_dump_signal(tsig) ? &act : NULL;
sigaction(hsig, iact, &oact);
- if (oact.sa_sigaction != (void *)SIG_IGN) {
- thand = TARGET_SIG_DFL;
- }
+ }
+
+ if (oact.sa_sigaction != (void *)SIG_IGN) {
+ thand = TARGET_SIG_DFL;
}
sigact_table[tsig - 1]._sa_handler = thand;
}
@@ -711,7 +734,12 @@ void dump_core_and_abort(CPUArchState *env, int target_sig)
TaskState *ts = (TaskState *)cpu->opaque;
int host_sig, core_dumped = 0;
- host_sig = target_to_host_signal(target_sig);
+ /* On exit, undo the remapping of SIGABRT. */
+ if (target_sig == TARGET_SIGABRT) {
+ host_sig = SIGABRT;
+ } else {
+ host_sig = target_to_host_signal(target_sig);
+ }
trace_user_dump_core_and_abort(env, target_sig, host_sig);
gdb_signalled(env, target_sig);