[FFmpeg-devel] [PATCH 1/2] ffmpeg: use sigaction() instead of signal() on linux

[Andriy Gelman]

On Sat, 28. Nov 14:46, Andriy Gelman wrote:
> From: Andriy Gelman <andriy.gelman at gmail.com>
> 
> As per signal() help (man 2 signal) the semantics of using signal may
> vary across platforms. It is suggested to use sigaction() instead.
> 
> On my system, the capture signal is reset to the default handler after
> the first call thus failing to properly handle multiple SIGINTs.
> 
> Signed-off-by: Andriy Gelman <andriy.gelman at gmail.com>
> ---
>  fftools/ffmpeg.c | 31 +++++++++++++++++++++++++++----
>  1 file changed, 27 insertions(+), 4 deletions(-)
> 
> diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
> index 80f436eab3..01f4ef15d8 100644
> --- a/fftools/ffmpeg.c
> +++ b/fftools/ffmpeg.c
> @@ -393,8 +393,30 @@ 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;
> +    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;
> @@ -413,14 +435,15 @@ 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);
> +    SIGNAL(SIGTERM, sigterm_handler);
> +
>  #ifdef SIGXCPU
> -    signal(SIGXCPU, sigterm_handler);
> +    SIGNAL(SIGXCPU, sigterm_handler);
>  #endif
>  #ifdef SIGPIPE
>      signal(SIGPIPE, SIG_IGN); /* Broken pipe (POSIX). */

ping

--
Andriy