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From: Richard Henderson <richard.henderson@linaro.org>
To: qemu-devel@nongnu.org
Cc: deller@gmx.de
Subject: [PATCH v4 01/10] linux-user: Split out die_with_signal
Date: Tue, 22 Aug 2023 22:16:06 -0700	[thread overview]
Message-ID: <20230823051615.1297706-2-richard.henderson@linaro.org> (raw)
In-Reply-To: <20230823051615.1297706-1-richard.henderson@linaro.org>

Because we trap so many signals for use by the guest,
we have to take extra steps to exit properly.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/signal.c | 52 ++++++++++++++++++++++++---------------------
 1 file changed, 28 insertions(+), 24 deletions(-)

diff --git a/linux-user/signal.c b/linux-user/signal.c
index 748a98f3e5..e1cd111a1b 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -694,6 +694,33 @@ void cpu_loop_exit_sigbus(CPUState *cpu, target_ulong addr,
 }
 
 /* abort execution with signal */
+static G_NORETURN
+void die_with_signal(int sig)
+{
+    struct sigaction act = {
+        .sa_handler = SIG_DFL,
+    };
+
+    /*
+     * The proper exit code for dying from an uncaught signal is -<signal>.
+     * The kernel doesn't allow exit() or _exit() to pass a negative value.
+     * To get the proper exit code we need to actually die from an uncaught
+     * signal.  Here the default signal handler is installed, we send
+     * the signal and we wait for it to arrive.
+     */
+    sigfillset(&act.sa_mask);
+    sigaction(sig, &act, NULL);
+
+    kill(getpid(), sig);
+
+    /* Make sure the signal isn't masked (reusing the mask inside of act). */
+    sigdelset(&act.sa_mask, sig);
+    sigsuspend(&act.sa_mask);
+
+    /* unreachable */
+    abort();
+}
+
 static G_NORETURN
 void dump_core_and_abort(CPUArchState *cpu_env, int target_sig)
 {
@@ -701,7 +728,6 @@ void dump_core_and_abort(CPUArchState *cpu_env, int target_sig)
     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);
     trace_user_dump_core_and_abort(env, target_sig, host_sig);
@@ -725,29 +751,7 @@ void dump_core_and_abort(CPUArchState *cpu_env, int target_sig)
     }
 
     preexit_cleanup(cpu_env, 128 + target_sig);
-
-    /* The proper exit code for dying from an uncaught signal is
-     * -<signal>.  The kernel doesn't allow exit() or _exit() to pass
-     * a negative value.  To get the proper exit code we need to
-     * actually die from an uncaught signal.  Here the default signal
-     * handler is installed, we send ourself a signal and we wait for
-     * it to arrive. */
-    sigfillset(&act.sa_mask);
-    act.sa_handler = SIG_DFL;
-    act.sa_flags = 0;
-    sigaction(host_sig, &act, NULL);
-
-    /* For some reason raise(host_sig) doesn't send the signal when
-     * statically linked on x86-64. */
-    kill(getpid(), host_sig);
-
-    /* Make sure the signal isn't masked (just reuse the mask inside
-    of act) */
-    sigdelset(&act.sa_mask, host_sig);
-    sigsuspend(&act.sa_mask);
-
-    /* unreachable */
-    abort();
+    die_with_signal(host_sig);
 }
 
 /* queue a signal so that it will be send to the virtual CPU as soon
-- 
2.34.1



  reply	other threads:[~2023-08-23  5:17 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-23  5:16 [PATCH v4 00/10] linux-user: Detect and report host crashes Richard Henderson
2023-08-23  5:16 ` Richard Henderson [this message]
2023-08-23 12:55   ` [PATCH v4 01/10] linux-user: Split out die_with_signal Philippe Mathieu-Daudé
2023-08-23  5:16 ` [PATCH v4 02/10] linux-user: Exit not abort in die_with_backtrace Richard Henderson
2023-08-23 12:55   ` Philippe Mathieu-Daudé
2023-08-23  5:16 ` [PATCH v4 03/10] linux-user: Use die_with_signal with abort Richard Henderson
2023-08-23  5:16 ` [PATCH v4 04/10] linux-user: Detect and report host crashes Richard Henderson
2023-08-23  5:16 ` [PATCH v4 05/10] linux-user: Only register handlers for core_dump_signal by default Richard Henderson
2023-08-23  5:16 ` [PATCH v4 06/10] linux-user: Map unsupported signals to an out-of-bounds value Richard Henderson
2023-08-23  5:16 ` [PATCH v4 07/10] linux-user: Remap SIGPROF when CONFIG_GPROF Richard Henderson
2023-08-23  5:16 ` [PATCH v4 08/10] linux-user: Simplify signal_init Richard Henderson
2023-08-23  5:16 ` [PATCH v4 09/10] linux-user: Split out host_sig{segv,bus}_handler Richard Henderson
2023-08-23  5:16 ` [PATCH v4 10/10] linux-user: Detect and report host SIGILL, SIGFPE, SIGTRAP Richard Henderson
2023-09-09 19:12 ` [PATCH v4 00/10] linux-user: Detect and report host crashes Richard Henderson
2023-09-12  9:45   ` Helge Deller
2023-09-12 10:34     ` Michael Tokarev
2023-09-18 14:05       ` Helge Deller
2023-09-19  7:40         ` Michael Tokarev
2023-09-19  8:00           ` Helge Deller
2023-09-19  8:26             ` Michael Tokarev
2023-09-19  8:38               ` Richard Henderson
2023-09-19  9:17                 ` Helge Deller
2023-09-19 13:01                 ` Michael Tokarev
2023-09-19  8:29         ` Richard Henderson

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