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Diffstat (limited to 'linux-user/signal.c')
-rw-r--r--linux-user/signal.c146
1 files changed, 110 insertions, 36 deletions
diff --git a/linux-user/signal.c b/linux-user/signal.c
index c8a1da0749..7d6246f448 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -197,6 +197,55 @@ void target_to_host_old_sigset(sigset_t *sigset,
target_to_host_sigset(sigset, &d);
}
+/* Wrapper for sigprocmask function
+ * Emulates a sigprocmask in a safe way for the guest. Note that set and oldset
+ * are host signal set, not guest ones. This wraps the sigprocmask host calls
+ * that should be protected (calls originated from guest)
+ */
+int do_sigprocmask(int how, const sigset_t *set, sigset_t *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 */
static inline void host_to_target_siginfo_noswap(target_siginfo_t *tinfo,
@@ -370,7 +419,8 @@ void signal_init(void)
static inline struct sigqueue *alloc_sigqueue(CPUArchState *env)
{
- TaskState *ts = env->opaque;
+ CPUState *cpu = ENV_GET_CPU(env);
+ TaskState *ts = cpu->opaque;
struct sigqueue *q = ts->first_free;
if (!q)
return NULL;
@@ -380,7 +430,9 @@ static inline struct sigqueue *alloc_sigqueue(CPUArchState *env)
static inline void free_sigqueue(CPUArchState *env, struct sigqueue *q)
{
- TaskState *ts = env->opaque;
+ CPUState *cpu = ENV_GET_CPU(env);
+ TaskState *ts = cpu->opaque;
+
q->next = ts->first_free;
ts->first_free = q;
}
@@ -388,8 +440,9 @@ static inline void free_sigqueue(CPUArchState *env, struct sigqueue *q)
/* abort execution with signal */
static void QEMU_NORETURN force_sig(int target_sig)
{
- CPUArchState *env = thread_cpu->env_ptr;
- TaskState *ts = (TaskState *)env->opaque;
+ CPUState *cpu = thread_cpu;
+ CPUArchState *env = cpu->env_ptr;
+ TaskState *ts = (TaskState *)cpu->opaque;
int host_sig, core_dumped = 0;
struct sigaction act;
host_sig = target_to_host_signal(target_sig);
@@ -440,7 +493,8 @@ static void QEMU_NORETURN force_sig(int target_sig)
as possible */
int queue_signal(CPUArchState *env, int sig, target_siginfo_t *info)
{
- TaskState *ts = env->opaque;
+ CPUState *cpu = ENV_GET_CPU(env);
+ TaskState *ts = cpu->opaque;
struct emulated_sigtable *k;
struct sigqueue *q, **pq;
abi_ulong handler;
@@ -453,6 +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);
@@ -774,8 +841,9 @@ static int
setup_sigcontext(struct target_sigcontext *sc, struct target_fpstate *fpstate,
CPUX86State *env, abi_ulong mask, abi_ulong fpstate_addr)
{
- int err = 0;
- uint16_t magic;
+ CPUState *cs = CPU(x86_env_get_cpu(env));
+ int err = 0;
+ uint16_t magic;
/* already locked in setup_frame() */
err |= __put_user(env->segs[R_GS].selector, (unsigned int *)&sc->gs);
@@ -790,7 +858,7 @@ setup_sigcontext(struct target_sigcontext *sc, struct target_fpstate *fpstate,
err |= __put_user(env->regs[R_EDX], &sc->edx);
err |= __put_user(env->regs[R_ECX], &sc->ecx);
err |= __put_user(env->regs[R_EAX], &sc->eax);
- err |= __put_user(env->exception_index, &sc->trapno);
+ err |= __put_user(cs->exception_index, &sc->trapno);
err |= __put_user(env->error_code, &sc->err);
err |= __put_user(env->eip, &sc->eip);
err |= __put_user(env->segs[R_CS].selector, (unsigned int *)&sc->cs);
@@ -1050,7 +1118,7 @@ long do_sigreturn(CPUX86State *env)
}
target_to_host_sigset_internal(&set, &target_set);
- sigprocmask(SIG_SETMASK, &set, NULL);
+ do_sigprocmask(SIG_SETMASK, &set, NULL);
/* restore registers */
if (restore_sigcontext(env, &frame->sc, &eax))
@@ -1075,7 +1143,7 @@ long do_rt_sigreturn(CPUX86State *env)
if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1))
goto badframe;
target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
- sigprocmask(SIG_SETMASK, &set, NULL);
+ do_sigprocmask(SIG_SETMASK, &set, NULL);
if (restore_sigcontext(env, &frame->uc.tuc_mcontext, &eax))
goto badframe;
@@ -1214,7 +1282,7 @@ static int target_restore_sigframe(CPUARMState *env,
uint64_t pstate;
target_to_host_sigset(&set, &sf->uc.tuc_sigmask);
- sigprocmask(SIG_SETMASK, &set, NULL);
+ do_sigprocmask(SIG_SETMASK, &set, NULL);
for (i = 0; i < 31; i++) {
__get_user(env->xregs[i], &sf->uc.tuc_mcontext.regs[i]);
@@ -1334,7 +1402,7 @@ static void setup_frame(int sig, struct target_sigaction *ka,
long do_rt_sigreturn(CPUARMState *env)
{
- struct target_rt_sigframe *frame;
+ struct target_rt_sigframe *frame = NULL;
abi_ulong frame_addr = env->xregs[31];
if (frame_addr & 15) {
@@ -1855,7 +1923,7 @@ static long do_sigreturn_v1(CPUARMState *env)
}
target_to_host_sigset_internal(&host_set, &set);
- sigprocmask(SIG_SETMASK, &host_set, NULL);
+ do_sigprocmask(SIG_SETMASK, &host_set, NULL);
if (restore_sigcontext(env, &frame->sc))
goto badframe;
@@ -1936,7 +2004,7 @@ static int do_sigframe_return_v2(CPUARMState *env, target_ulong frame_addr,
abi_ulong *regspace;
target_to_host_sigset(&host_set, &uc->tuc_sigmask);
- sigprocmask(SIG_SETMASK, &host_set, NULL);
+ do_sigprocmask(SIG_SETMASK, &host_set, NULL);
if (restore_sigcontext(env, &uc->tuc_mcontext))
return 1;
@@ -2027,7 +2095,7 @@ static long do_rt_sigreturn_v1(CPUARMState *env)
goto badframe;
target_to_host_sigset(&host_set, &frame->uc.tuc_sigmask);
- sigprocmask(SIG_SETMASK, &host_set, NULL);
+ do_sigprocmask(SIG_SETMASK, &host_set, NULL);
if (restore_sigcontext(env, &frame->uc.tuc_mcontext))
goto badframe;
@@ -2438,7 +2506,7 @@ long do_sigreturn(CPUSPARCState *env)
}
target_to_host_sigset_internal(&host_set, &set);
- sigprocmask(SIG_SETMASK, &host_set, NULL);
+ do_sigprocmask(SIG_SETMASK, &host_set, NULL);
if (err)
goto segv_and_exit;
@@ -2561,7 +2629,7 @@ void sparc64_set_context(CPUSPARCState *env)
goto do_sigsegv;
}
target_to_host_sigset_internal(&set, &target_set);
- sigprocmask(SIG_SETMASK, &set, NULL);
+ do_sigprocmask(SIG_SETMASK, &set, NULL);
}
env->pc = pc;
env->npc = npc;
@@ -2650,7 +2718,7 @@ void sparc64_get_context(CPUSPARCState *env)
err = 0;
- sigprocmask(0, NULL, &set);
+ do_sigprocmask(0, NULL, &set);
host_to_target_sigset_internal(&target_set, &set);
if (TARGET_NSIG_WORDS == 1) {
err |= __put_user(target_set.sig[0],
@@ -2985,7 +3053,7 @@ long do_sigreturn(CPUMIPSState *regs)
}
target_to_host_sigset_internal(&blocked, &target_set);
- sigprocmask(SIG_SETMASK, &blocked, NULL);
+ do_sigprocmask(SIG_SETMASK, &blocked, NULL);
if (restore_sigcontext(regs, &frame->sf_sc))
goto badframe;
@@ -3089,7 +3157,7 @@ long do_rt_sigreturn(CPUMIPSState *env)
goto badframe;
target_to_host_sigset(&blocked, &frame->rs_uc.tuc_sigmask);
- sigprocmask(SIG_SETMASK, &blocked, NULL);
+ do_sigprocmask(SIG_SETMASK, &blocked, NULL);
if (restore_sigcontext(env, &frame->rs_uc.tuc_mcontext))
goto badframe;
@@ -3379,7 +3447,7 @@ long do_sigreturn(CPUSH4State *regs)
goto badframe;
target_to_host_sigset_internal(&blocked, &target_set);
- sigprocmask(SIG_SETMASK, &blocked, NULL);
+ do_sigprocmask(SIG_SETMASK, &blocked, NULL);
if (restore_sigcontext(regs, &frame->sc, &r0))
goto badframe;
@@ -3408,7 +3476,7 @@ long do_rt_sigreturn(CPUSH4State *regs)
goto badframe;
target_to_host_sigset(&blocked, &frame->uc.tuc_sigmask);
- sigprocmask(SIG_SETMASK, &blocked, NULL);
+ do_sigprocmask(SIG_SETMASK, &blocked, NULL);
if (restore_sigcontext(regs, &frame->uc.tuc_mcontext, &r0))
goto badframe;
@@ -3638,7 +3706,7 @@ long do_sigreturn(CPUMBState *env)
goto badframe;
}
target_to_host_sigset_internal(&set, &target_set);
- sigprocmask(SIG_SETMASK, &set, NULL);
+ do_sigprocmask(SIG_SETMASK, &set, NULL);
restore_sigcontext(&frame->uc.tuc_mcontext, env);
/* We got here through a sigreturn syscall, our path back is via an
@@ -3813,7 +3881,7 @@ long do_sigreturn(CPUCRISState *env)
goto badframe;
}
target_to_host_sigset_internal(&set, &target_set);
- sigprocmask(SIG_SETMASK, &set, NULL);
+ do_sigprocmask(SIG_SETMASK, &set, NULL);
restore_sigcontext(&frame->sc, env);
unlock_user_struct(frame, frame_addr, 0);
@@ -3975,8 +4043,6 @@ static void setup_rt_frame(int sig, struct target_sigaction *ka,
struct target_rt_sigframe *frame;
abi_ulong info_addr, uc_addr;
- frame_addr = get_sigframe(ka, env, sizeof *frame);
-
frame_addr = get_sigframe(ka, env, sizeof(*frame));
if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) {
goto give_sigsegv;
@@ -4344,7 +4410,7 @@ long do_sigreturn(CPUS390XState *env)
}
target_to_host_sigset_internal(&set, &target_set);
- sigprocmask(SIG_SETMASK, &set, NULL); /* ~_BLOCKABLE? */
+ do_sigprocmask(SIG_SETMASK, &set, NULL); /* ~_BLOCKABLE? */
if (restore_sigregs(env, &frame->sregs)) {
goto badframe;
@@ -4372,7 +4438,7 @@ long do_rt_sigreturn(CPUS390XState *env)
}
target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
- sigprocmask(SIG_SETMASK, &set, NULL); /* ~_BLOCKABLE? */
+ do_sigprocmask(SIG_SETMASK, &set, NULL); /* ~_BLOCKABLE? */
if (restore_sigregs(env, &frame->uc.tuc_mcontext)) {
goto badframe;
@@ -4900,7 +4966,7 @@ long do_sigreturn(CPUPPCState *env)
goto sigsegv;
#endif
target_to_host_sigset_internal(&blocked, &set);
- sigprocmask(SIG_SETMASK, &blocked, NULL);
+ do_sigprocmask(SIG_SETMASK, &blocked, NULL);
if (__get_user(sr_addr, &sc->regs))
goto sigsegv;
@@ -4944,7 +5010,7 @@ static int do_setcontext(struct target_ucontext *ucp, CPUPPCState *env, int sig)
return 1;
target_to_host_sigset_internal(&blocked, &set);
- sigprocmask(SIG_SETMASK, &blocked, NULL);
+ do_sigprocmask(SIG_SETMASK, &blocked, NULL);
if (restore_user_regs(env, mcp, sig))
goto sigsegv;
@@ -5318,7 +5384,7 @@ long do_sigreturn(CPUM68KState *env)
}
target_to_host_sigset_internal(&set, &target_set);
- sigprocmask(SIG_SETMASK, &set, NULL);
+ do_sigprocmask(SIG_SETMASK, &set, NULL);
/* restore registers */
@@ -5346,7 +5412,7 @@ long do_rt_sigreturn(CPUM68KState *env)
goto badframe;
target_to_host_sigset_internal(&set, &target_set);
- sigprocmask(SIG_SETMASK, &set, NULL);
+ do_sigprocmask(SIG_SETMASK, &set, NULL);
/* restore registers */
@@ -5593,7 +5659,7 @@ long do_sigreturn(CPUAlphaState *env)
}
target_to_host_sigset_internal(&set, &target_set);
- sigprocmask(SIG_SETMASK, &set, NULL);
+ do_sigprocmask(SIG_SETMASK, &set, NULL);
if (restore_sigcontext(env, sc)) {
goto badframe;
@@ -5616,7 +5682,7 @@ long do_rt_sigreturn(CPUAlphaState *env)
goto badframe;
}
target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
- sigprocmask(SIG_SETMASK, &set, NULL);
+ do_sigprocmask(SIG_SETMASK, &set, NULL);
if (restore_sigcontext(env, &frame->uc.tuc_mcontext)) {
goto badframe;
@@ -5675,7 +5741,7 @@ void process_pending_signals(CPUArchState *cpu_env)
struct emulated_sigtable *k;
struct target_sigaction *sa;
struct sigqueue *q;
- TaskState *ts = cpu_env->opaque;
+ TaskState *ts = cpu->opaque;
if (!ts->signal_pending)
return;
@@ -5710,6 +5776,14 @@ 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) {
@@ -5733,7 +5807,7 @@ void process_pending_signals(CPUArchState *cpu_env)
sigaddset(&set, target_to_host_signal(sig));
/* block signals in the handler using Linux */
- sigprocmask(SIG_BLOCK, &set, &old_set);
+ do_sigprocmask(SIG_BLOCK, &set, &old_set);
/* save the previous blocked signal state to restore it at the
end of the signal execution (see do_sigreturn) */
host_to_target_sigset_internal(&target_old_set, &old_set);
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2025-04-25 10:24:31 +0200