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         if(!pthread_user_data_internal(pthread_self())->running) {
  23                 sigsuspend(&sigset);
  24         }
  25 }
  26
  27 void pthread_pause_enable() {
  28         //Add thread to internal registry
  29         pthread_user_data_internal(pthread_self());
  30
  31         //Nesting signals too deep is not good for stack
  32         //You can get runtime stats using following command:
  33         //grep -i sig /proc/$(pgrep binary)/status
  34         struct rlimit sigq = {.rlim_cur = 32, .rlim_max=32};
  35         setrlimit(RLIMIT_SIGPENDING, &sigq);
  36
  37         //Setup signal handler
  38         signal(PTHREAD_XSIG_STOP, pthread_pause_handler);
  39
  40         //Unblock signal
  41         sigset_t sigset;
  42         sigemptyset(&sigset);
  43         sigaddset(&sigset, PTHREAD_XSIG_STOP);
  44         pthread_sigmask(SIG_UNBLOCK, &sigset, NULL);
  45 }
  46
  47 void pthread_pause_disable() {
  48         //Add thread to internal registry
  49         pthread_user_data_internal(pthread_self());
  50
  51         //Block signal
  52         sigset_t sigset;
  53         sigemptyset(&sigset);
  54         sigaddset(&sigset, PTHREAD_XSIG_STOP);
  55         pthread_sigmask(SIG_BLOCK, &sigset, NULL);
  56 }
  57
  58 int pthread_pause(pthread_t thread) {
  59         //Set thread as paused and notify it via signal (wait when queue full)
  60         pthread_user_data_internal(thread)->running = 0;
  61         while(pthread_kill(thread, PTHREAD_XSIG_STOP) == EAGAIN) usleep(1000);
  62         return 0;
  63 }
  64
  65 int pthread_unpause(pthread_t thread) {
  66         //Set thread as running and notify it via signal (wait when queue full)
  67         pthread_user_data_internal(thread)->running = 1;
  68         while(pthread_kill(thread, PTHREAD_XSIG_STOP) == EAGAIN) usleep(1000);
  69         return 0;
  70 }