diff --git a/linux-user/signal.c b/linux-user/signal.c index c1e664f97a..046159dd0c 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -498,18 +498,30 @@ static int core_dump_signal(int sig) static void signal_table_init(void) { - int host_sig, target_sig; + int host_sig, target_sig, count; /* - * Nasty hack: Reverse SIGRTMIN and SIGRTMAX to avoid overlap with - * host libpthread signals. This assumes no one actually uses SIGRTMAX :-/ + * Signals are supported starting from TARGET_SIGRTMIN and going up + * until we run out of host realtime signals. + * glibc at least uses only the lower 2 rt signals and probably + * nobody's using the upper ones. + * it's why SIGRTMIN (34) is generally greater than __SIGRTMIN (32) * To fix this properly we need to do manual signal delivery multiplexed * over a single host signal. + * Attempts for configure "missing" signals via sigaction will be + * silently ignored. */ - host_to_target_signal_table[__SIGRTMIN] = __SIGRTMAX; - host_to_target_signal_table[__SIGRTMAX] = __SIGRTMIN; + for (host_sig = SIGRTMIN; host_sig <= SIGRTMAX; host_sig++) { + target_sig = host_sig - SIGRTMIN + TARGET_SIGRTMIN; + if (target_sig <= TARGET_NSIG) { + host_to_target_signal_table[host_sig] = target_sig; + } + } /* generate signal conversion tables */ + for (target_sig = 1; target_sig <= TARGET_NSIG; target_sig++) { + target_to_host_signal_table[target_sig] = _NSIG; /* poison */ + } for (host_sig = 1; host_sig < _NSIG; host_sig++) { if (host_to_target_signal_table[host_sig] == 0) { host_to_target_signal_table[host_sig] = host_sig; @@ -519,6 +531,15 @@ static void signal_table_init(void) target_to_host_signal_table[target_sig] = host_sig; } } + + if (trace_event_get_state_backends(TRACE_SIGNAL_TABLE_INIT)) { + for (target_sig = 1, count = 0; target_sig <= TARGET_NSIG; target_sig++) { + if (target_to_host_signal_table[target_sig] == _NSIG) { + count++; + } + } + trace_signal_table_init(count); + } } void signal_init(void) @@ -817,6 +838,8 @@ int do_sigaction(int sig, const struct target_sigaction *act, int host_sig; int ret = 0; + trace_signal_do_sigaction_guest(sig, TARGET_NSIG); + if (sig < 1 || sig > TARGET_NSIG || sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP) { return -TARGET_EINVAL; } @@ -847,6 +870,23 @@ int do_sigaction(int sig, const struct target_sigaction *act, /* we update the host linux signal state */ host_sig = target_to_host_signal(sig); + trace_signal_do_sigaction_host(host_sig, TARGET_NSIG); + if (host_sig > SIGRTMAX) { + /* we don't have enough host signals to map all target signals */ + qemu_log_mask(LOG_UNIMP, "Unsupported target signal #%d, ignored\n", + sig); + /* + * we don't return an error here because some programs try to + * register an handler for all possible rt signals even if they + * don't need it. + * An error here can abort them whereas there can be no problem + * to not have the signal available later. + * This is the case for golang, + * See https://github.com/golang/go/issues/33746 + * So we silently ignore the error. + */ + return 0; + } if (host_sig != SIGSEGV && host_sig != SIGBUS) { sigfillset(&act1.sa_mask); act1.sa_flags = SA_SIGINFO; diff --git a/linux-user/trace-events b/linux-user/trace-events index f6de1b8bef..0296133dae 100644 --- a/linux-user/trace-events +++ b/linux-user/trace-events @@ -1,6 +1,9 @@ # See docs/devel/tracing.txt for syntax documentation. # signal.c +signal_table_init(int i) "number of unavailable signals: %d" +signal_do_sigaction_guest(int sig, int max) "target signal %d (MAX %d)" +signal_do_sigaction_host(int sig, int max) "host signal %d (MAX %d)" # */signal.c user_setup_frame(void *env, uint64_t frame_addr) "env=%p frame_addr=0x%"PRIx64 user_setup_rt_frame(void *env, uint64_t frame_addr) "env=%p frame_addr=0x%"PRIx64