[FFmpeg-cvslog] ffmpeg: use sigaction() instead of signal() on linux

[Andriy Gelman]

ffmpeg | branch: master | Andriy Gelman <andriy.gelman at gmail.com> | Sat Nov 28 14:46:53 2020 -0500| [35eb5eeca809bc48463302dc29b5d46cd66e4a72] | committer: Andriy Gelman

ffmpeg: use sigaction() instead of signal() on linux

As per signal() help (man 2 signal) the semantics of using signal may
vary across platforms. It is suggested to use sigaction() instead.

Reviewed-by: Zane van Iperen <zane at zanevaniperen.com>
Signed-off-by: Andriy Gelman <andriy.gelman at gmail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=35eb5eeca809bc48463302dc29b5d46cd66e4a72
---

 fftools/ffmpeg.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
index 84a60f944a..4419c68d11 100644
--- a/fftools/ffmpeg.c
+++ b/fftools/ffmpeg.c
@@ -394,8 +394,30 @@ static BOOL WINAPI CtrlHandler(DWORD fdwCtrlType)
 }
 #endif
 
+#ifdef __linux__
+#define SIGNAL(sig, func)               \
+    do {                                \
+        action.sa_handler = func;       \
+        sigaction(sig, &action, NULL);  \
+    } while (0)
+#else
+#define SIGNAL(sig, func) \
+    signal(sig, func)
+#endif
+
 void term_init(void)
 {
+#if defined __linux__
+    struct sigaction action = {0};
+    action.sa_handler = sigterm_handler;
+
+    /* block other interrupts while processing this one */
+    sigfillset(&action.sa_mask);
+
+    /* restart interruptible functions (i.e. don't fail with EINTR)  */
+    action.sa_flags = SA_RESTART;
+#endif
+
 #if HAVE_TERMIOS_H
     if (!run_as_daemon && stdin_interaction) {
         struct termios tty;
@@ -414,14 +436,14 @@ void term_init(void)
 
             tcsetattr (0, TCSANOW, &tty);
         }
-        signal(SIGQUIT, sigterm_handler); /* Quit (POSIX).  */
+        SIGNAL(SIGQUIT, sigterm_handler); /* Quit (POSIX).  */
     }
 #endif
 
-    signal(SIGINT , sigterm_handler); /* Interrupt (ANSI).    */
-    signal(SIGTERM, sigterm_handler); /* Termination (ANSI).  */
+    SIGNAL(SIGINT , sigterm_handler); /* Interrupt (ANSI).    */
+    SIGNAL(SIGTERM, sigterm_handler); /* Termination (ANSI).  */
 #ifdef SIGXCPU
-    signal(SIGXCPU, sigterm_handler);
+    SIGNAL(SIGXCPU, sigterm_handler);
 #endif
 #ifdef SIGPIPE
     signal(SIGPIPE, SIG_IGN); /* Broken pipe (POSIX). */