libc-top-half/musl/src/thread/pthread_atfork.c

   1 #include <pthread.h>
   2 #include "libc.h"
   3 #include "lock.h"
   4
   5 static struct atfork_funcs {
   6         void (*prepare)(void);
   7         void (*parent)(void);
   8         void (*child)(void);
   9         struct atfork_funcs *prev, *next;
  10 } *funcs;
  11
  12 static volatile int lock[1];
  13
  14 void __fork_handler(int who)
  15 {
  16         struct atfork_funcs *p;
  17         if (!funcs) return;
  18         if (who < 0) {
  19                 LOCK(lock);
  20                 for (p=funcs; p; p = p->next) {
  21                         if (p->prepare) p->prepare();
  22                         funcs = p;
  23                 }
  24         } else {
  25                 for (p=funcs; p; p = p->prev) {
  26                         if (!who && p->parent) p->parent();
  27                         else if (who && p->child) p->child();
  28                         funcs = p;
  29                 }
  30                 UNLOCK(lock);
  31         }
  32 }
  33
  34 int pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void))
  35 {
  36         struct atfork_funcs *new = malloc(sizeof *new);
  37         if (!new) return -1;
  38
  39         LOCK(lock);
  40         new->next = funcs;
  41         new->prev = 0;
  42         new->prepare = prepare;
  43         new->parent = parent;
  44         new->child = child;
  45         if (funcs) funcs->prev = new;
  46         funcs = new;
  47         UNLOCK(lock);
  48         return 0;
  49 }