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author | Richard Henderson <richard.henderson@linaro.org> | 2023-09-30 12:05:11 -0700 |
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committer | Richard Henderson <richard.henderson@linaro.org> | 2023-10-18 16:25:06 -0700 |
commit | 38ee0a7dfb4b15407678df26448e4a18fd9a51d4 (patch) | |
tree | 5e7efbde27a86f40b10919cdf43f057b47db941c /linux-user/signal.c | |
parent | 4a6ebc19a7e2d013a0e2ca79452ea733b1d5b686 (diff) | |
download | qemu-38ee0a7dfb4b15407678df26448e4a18fd9a51d4.zip qemu-38ee0a7dfb4b15407678df26448e4a18fd9a51d4.tar.gz qemu-38ee0a7dfb4b15407678df26448e4a18fd9a51d4.tar.bz2 |
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.c | 42 |
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); |