src/thread/pthread_atfork.c

   1 #include <pthread.h>
   2 #include "libc.h"
   3
   4 static struct atfork_funcs {
   5         void (*prepare)(void);
   6         void (*parent)(void);
   7         void (*child)(void);
   8         struct atfork_funcs *prev, *next;
   9 } *funcs;
  10
  11 static volatile int lock[2];
  12
  13 void __fork_handler(int who)
  14 {
  15         struct atfork_funcs *p;
  16         if (!funcs) return;
  17         if (who < 0) {
  18                 LOCK(lock);
  19                 for (p=funcs; p; p = p->next) {
  20                         if (p->prepare) p->prepare();
  21                         funcs = p;
  22                 }
  23         } else {
  24                 for (p=funcs; p; p = p->prev) {
  25                         if (!who && p->parent) p->parent();
  26                         else if (who && p->child) p->child();
  27                         funcs = p;
  28                 }
  29                 UNLOCK(lock);
  30         }
  31 }
  32
  33 int pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void))
  34 {
  35         struct atfork_funcs *new = malloc(sizeof *new);
  36         if (!new) return -1;
  37
  38         LOCK(lock);
  39         new->next = funcs;
  40         new->prev = 0;
  41         new->prepare = prepare;
  42         new->parent = parent;
  43         new->child = child;
  44         if (funcs) funcs->prev = new;
  45         funcs = new;
  46         UNLOCK(lock);
  47         return 0;
  48 }