sig-monitor: Dump stack atomically

[src/app-framework-binder.git] / src / sig-monitor.c

diff --git a/src/sig-monitor.c b/src/sig-monitor.c
index 3e16f72..a92fc81 100644 (file)
--- a/src/sig-monitor.c
+++ b/src/sig-monitor.c
@@ -18,16 +18,20 @@
 #define _GNU_SOURCE
 
 #include <stdlib.h>
+#include <stdio.h>
 #include <signal.h>
 #include <string.h>
 #include <setjmp.h>
 #include <time.h>
 #include <unistd.h>
 #include <sys/syscall.h>
+#include <execinfo.h>
 
 #include "sig-monitor.h"
 #include "verbose.h"
 
+#define SIG_FOR_TIMER   SIGVTALRM
+
 /* local handler */
 static _Thread_local sigjmp_buf *error_handler;
 
@@ -35,6 +39,42 @@ static _Thread_local sigjmp_buf *error_handler;
 static _Thread_local int thread_timer_set;
 static _Thread_local timer_t thread_timerid;
 
+/*
+ * Dumps the current stack
+ */
+static void dumpstack(int crop, int signum)
+{
+       int idx, count, rc;
+       void *addresses[100];
+       char **locations;
+       char buffer[8000];
+       size_t pos, length;
+
+       count = backtrace(addresses, sizeof addresses / sizeof *addresses);
+       if (count <= crop)
+               crop = 0;
+       count -= crop;
+       locations = backtrace_symbols(&addresses[crop], count);
+       if (locations == NULL)
+               ERROR("can't get the backtrace (returned %d addresses)", count);
+       else {
+               length = sizeof buffer - 1;
+               pos = 0;
+               idx = 0;
+               while (pos < length && idx < count) {
+                       rc = snprintf(&buffer[pos], length - pos, " [%d/%d] %s\n", idx + 1, count, locations[idx]);
+                       pos += rc >= 0 ? rc : 0;
+                       idx++;
+               }
+               buffer[length] = 0;
+               if (signum)
+                       ERROR("BACKTRACE due to signal %s/%d:\n%s", strsignal(signum), signum, buffer);
+               else
+                       ERROR("BACKTRACE:\n%s", buffer);
+               free(locations);
+       }
+}
+
 /*
  * Creates a timer for the current thread
  *
@@ -49,7 +89,7 @@ static inline int timeout_create()
                rc = 0;
        else {
                sevp.sigev_notify = SIGEV_THREAD_ID;
-               sevp.sigev_signo = SIGALRM;
+               sevp.sigev_signo = SIG_FOR_TIMER;
                sevp.sigev_value.sival_ptr = NULL;
 #if defined(sigev_notify_thread_id)
                sevp.sigev_notify_thread_id = (pid_t)syscall(SYS_gettid);
@@ -107,6 +147,8 @@ static inline void timeout_delete()
 static void on_signal_terminate (int signum)
 {
        ERROR("Terminating signal %d received: %s", signum, strsignal(signum));
+       if (signum == SIGABRT)
+               dumpstack(3, signum);
        exit(1);
 }
 
@@ -116,6 +158,10 @@ static void on_signal_error(int signum)
        sigset_t sigset;
 
        ERROR("ALERT! signal %d received: %s", signum, strsignal(signum));
+       if (error_handler == NULL && signum == SIG_FOR_TIMER)
+               return;
+
+       dumpstack(3, signum);
 
        // unlock signal to allow a new signal to come
        if (error_handler != NULL) {
@@ -124,8 +170,6 @@ static void on_signal_error(int signum)
                sigprocmask(SIG_UNBLOCK, &sigset, 0);
                longjmp(*error_handler, signum);
        }
-       if (signum == SIGALRM)
-               return;
        ERROR("Unmonitored signal %d received: %s", signum, strsignal(signum));
        exit(2);
 }
@@ -146,8 +190,8 @@ static int install(void (*handler)(int), int *signals)
 
 int sig_monitor_init()
 {
-       static int sigerr[] = { SIGALRM, SIGSEGV, SIGFPE, 0 };
-       static int sigterm[] = { SIGINT, SIGABRT, 0 };
+       static int sigerr[] = { SIG_FOR_TIMER, SIGSEGV, SIGFPE, SIGILL, SIGBUS, 0 };
+       static int sigterm[] = { SIGINT, SIGABRT, SIGTERM, 0 };
 
        return (install(on_signal_error, sigerr) & install(on_signal_terminate, sigterm)) - 1;
 }
@@ -185,6 +229,3 @@ void sig_monitor(int timeout, void (*function)(int sig, void*), void *arg)
 }
 
 
-
-
-