c/pthread_extra/pthread_pause.c

   1 #define __PTHREAD_EXTRA_INTERNAL
   2
   3 #include <pthread.h>
   4 #include <pthread_extra.h>
   5 #include <signal.h>
   6 #include <errno.h>
   7 #include <unistd.h>
   8 #include <sys/resource.h>
   9 //#include <stdio.h>
  10 //#include <sys/time.h>
  11
  12 void pthread_pause_handler() {
  13         //Do nothing when there are more signals pending (to cleanup the queue)
  14         sigset_t pending;
  15         sigpending(&pending);
  16         if(sigismember(&pending, PTHREAD_XSIG_STOP)) return;
  17
  18         //Keep waiting for signals until we are supposed to be running
  19         sigset_t sigset;
  20         sigfillset(&sigset);
  21         sigdelset(&sigset, PTHREAD_XSIG_STOP);
  22         while(!pthread_user_data_internal(pthread_self())->running) {
  23                 sigsuspend(&sigset);
  24         }
  25 }
  26
  27 void pthread_pause_enable() {
  28         //Nesting signals too deep is not good for stack
  29         //You can get runtime stats using following command:
  30         //grep -i sig /proc/$(pgrep binary)/status
  31         struct rlimit sigq = {.rlim_cur = 32, .rlim_max=32};
  32         setrlimit(RLIMIT_SIGPENDING, &sigq);
  33
  34         //Setup signal handler
  35         signal(PTHREAD_XSIG_STOP, pthread_pause_handler);
  36
  37         //Unblock signal
  38         sigset_t sigset;
  39         sigemptyset(&sigset);
  40         sigaddset(&sigset, PTHREAD_XSIG_STOP);
  41         pthread_sigmask(SIG_UNBLOCK, &sigset, NULL);
  42 }
  43
  44 void pthread_pause_disable() {
  45         //Block signal
  46         sigset_t sigset;
  47         sigemptyset(&sigset);
  48         sigaddset(&sigset, PTHREAD_XSIG_STOP);
  49         pthread_sigmask(SIG_BLOCK, &sigset, NULL);
  50 }
  51
  52 int pthread_pause(pthread_t thread) {
  53         //Set thread as paused and notify it via signal (wait when queue full)
  54         pthread_user_data_internal(thread)->running = 0;
  55         while(pthread_kill(thread, PTHREAD_XSIG_STOP) == EAGAIN) usleep(1000);
  56         return 0;
  57 }
  58
  59 int pthread_unpause(pthread_t thread) {
  60         //Set thread as running and notify it via signal (wait when queue full)
  61         pthread_user_data_internal(thread)->running = 1;
  62         while(pthread_kill(thread, PTHREAD_XSIG_STOP) == EAGAIN) usleep(1000);
  63         return 0;
  64 }