diff options
| -rw-r--r-- | linux-user/qemu.h | 1 | ||||
| -rw-r--r-- | linux-user/signal.c | 62 |
2 files changed, 62 insertions, 1 deletions
diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 4d24e74775..36d4a738ea 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -126,6 +126,7 @@ typedef struct TaskState { #endif uint32_t stack_base; int used; /* non zero if used */ + bool sigsegv_blocked; /* SIGSEGV blocked by guest */ struct image_info *info; struct linux_binprm *bprm; diff --git a/linux-user/signal.c b/linux-user/signal.c index 9e6a4952a7..e5fb9332e3 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -204,7 +204,46 @@ void target_to_host_old_sigset(sigset_t *sigset, */ int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset) { - return sigprocmask(how, set, oldset); + int ret; + sigset_t val; + sigset_t *temp = NULL; + CPUState *cpu = thread_cpu; + TaskState *ts = (TaskState *)cpu->opaque; + bool segv_was_blocked = ts->sigsegv_blocked; + + if (set) { + bool has_sigsegv = sigismember(set, SIGSEGV); + val = *set; + temp = &val; + + sigdelset(temp, SIGSEGV); + + switch (how) { + case SIG_BLOCK: + if (has_sigsegv) { + ts->sigsegv_blocked = true; + } + break; + case SIG_UNBLOCK: + if (has_sigsegv) { + ts->sigsegv_blocked = false; + } + break; + case SIG_SETMASK: + ts->sigsegv_blocked = has_sigsegv; + break; + default: + g_assert_not_reached(); + } + } + + ret = sigprocmask(how, temp, oldset); + + if (oldset && segv_was_blocked) { + sigaddset(oldset, SIGSEGV); + } + + return ret; } /* siginfo conversion */ @@ -468,6 +507,19 @@ int queue_signal(CPUArchState *env, int sig, target_siginfo_t *info) k = &ts->sigtab[sig - 1]; queue = gdb_queuesig (); handler = sigact_table[sig - 1]._sa_handler; + + if (ts->sigsegv_blocked && sig == TARGET_SIGSEGV) { + /* Guest has blocked SIGSEGV but we got one anyway. Assume this + * is a forced SIGSEGV (ie one the kernel handles via force_sig_info + * because it got a real MMU fault). A blocked SIGSEGV in that + * situation is treated as if using the default handler. This is + * not correct if some other process has randomly sent us a SIGSEGV + * via kill(), but that is not easy to distinguish at this point, + * so we assume it doesn't happen. + */ + handler = TARGET_SIG_DFL; + } + if (!queue && handler == TARGET_SIG_DFL) { if (sig == TARGET_SIGTSTP || sig == TARGET_SIGTTIN || sig == TARGET_SIGTTOU) { kill(getpid(),SIGSTOP); @@ -5726,6 +5778,14 @@ void process_pending_signals(CPUArchState *cpu_env) handler = sa->_sa_handler; } + if (ts->sigsegv_blocked && sig == TARGET_SIGSEGV) { + /* Guest has blocked SIGSEGV but we got one anyway. Assume this + * is a forced SIGSEGV (ie one the kernel handles via force_sig_info + * because it got a real MMU fault), and treat as if default handler. + */ + handler = TARGET_SIG_DFL; + } + if (handler == TARGET_SIG_DFL) { /* default handler : ignore some signal. The other are job control or fatal */ if (sig == TARGET_SIGTSTP || sig == TARGET_SIGTTIN || sig == TARGET_SIGTTOU) { |