From 217f30001a73bc155a93ee5565405df970883dab Mon Sep 17 00:00:00 2001
From: Mike Blumenkrantz <zmike@samsung.com>
Date: Tue, 19 Jun 2018 14:04:45 -0400
Subject: [PATCH] eina_debug_bt: only enable SIGPROF handler when profiling is
 enabled

Summary:
if profiling is not enabled then reaching this signal handler will always
result in a crash

moreover, the signal handler has no functional value if profiling is not active,
so do not add it until that point

fix T7028

@fix
Depends on D6311

Reviewers: ManMower, devilhorns

Reviewed By: ManMower

Subscribers: cedric, #committers

Tags: #efl

Maniphest Tasks: T7028

Differential Revision: https://phab.enlightenment.org/D6312
---
 src/lib/eina/eina_debug_bt.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/src/lib/eina/eina_debug_bt.c b/src/lib/eina/eina_debug_bt.c
index 21b067c395..e769371b6e 100644
--- a/src/lib/eina/eina_debug_bt.c
+++ b/src/lib/eina/eina_debug_bt.c
@@ -52,6 +52,10 @@ static int                *_bt_cpu;
 static double _trace_t0 = 0.0;
 static Eina_Debug_Timer *_timer = NULL;
 
+#ifndef _WIN32
+static struct sigaction old_sigprof_action;
+#endif
+
 void
 _eina_debug_dump_fhandle_bt(FILE *f, void **bt, int btlen)
 {
@@ -196,6 +200,15 @@ _signal_init(void)
 #ifndef _WIN32
    struct sigaction sa;
 
+   memset(&sa, 0, sizeof(struct sigaction));
+
+   sa.sa_handler = SIG_DFL;
+   sa.sa_sigaction = NULL;
+   sa.sa_flags = SA_RESTART | SA_SIGINFO;
+   sigemptyset(&sa.sa_mask);
+   sigaction(SIG, &sa, &old_sigprof_action);
+
+   memset(&sa, 0, sizeof(struct sigaction));
    // set up signal handler for our profiling signal - eevery thread should
    // obey this (this is the case on linux - other OSs may vary)
    sa.sa_sigaction = _signal_handler;
@@ -212,6 +225,12 @@ _signal_init(void)
 #endif
 }
 
+static void
+_signal_shutdown(void)
+{
+   sigaction(SIG, &old_sigprof_action, NULL);
+}
+
 static void
 _collect_bt(pthread_t pth)
 {
@@ -290,6 +309,8 @@ static Eina_Bool
 _prof_on_cb(Eina_Debug_Session *session, int cid EINA_UNUSED, void *buffer, int size)
 {
    unsigned int time;
+
+   _signal_init();
    if (size >= 4)
      {
         memcpy(&time, buffer, 4);
@@ -305,6 +326,7 @@ _prof_off_cb(Eina_Debug_Session *session EINA_UNUSED, int cid EINA_UNUSED, void
 {
    eina_debug_timer_del(_timer);
    _timer = NULL;
+   _signal_shutdown();
    return EINA_TRUE;
 }
 
@@ -317,7 +339,6 @@ EINA_DEBUG_OPCODES_ARRAY_DEFINE(_OPS,
 Eina_Bool
 _eina_debug_bt_init(void)
 {
-   _signal_init();
    eina_semaphore_new(&_wait_for_bts_sem, 0);
    eina_debug_opcodes_register(NULL, _OPS(), NULL, NULL);
    return EINA_TRUE;