src/thread/pthread_atfork.c

   1 #include <pthread.h>
   2 #include <errno.h>
   3 #include "libc.h"
   4 #include "lock.h"
   5
   6 #define malloc __libc_malloc
   7 #define calloc undef
   8 #define realloc undef
   9 #define free undef
  10
  11 static struct atfork_funcs {
  12         void (*prepare)(void);
  13         void (*parent)(void);
  14         void (*child)(void);
  15         struct atfork_funcs *prev, *next;
  16 } *funcs;
  17
  18 static volatile int lock[1];
  19
  20 void __fork_handler(int who)
  21 {
  22         struct atfork_funcs *p;
  23         if (!funcs) return;
  24         if (who < 0) {
  25                 LOCK(lock);
  26                 for (p=funcs; p; p = p->next) {
  27                         if (p->prepare) p->prepare();
  28                         funcs = p;
  29                 }
  30         } else {
  31                 for (p=funcs; p; p = p->prev) {
  32                         if (!who && p->parent) p->parent();
  33                         else if (who && p->child) p->child();
  34                         funcs = p;
  35                 }
  36                 UNLOCK(lock);
  37         }
  38 }
  39
  40 int pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void))
  41 {
  42         struct atfork_funcs *new = malloc(sizeof *new);
  43         if (!new) return ENOMEM;
  44
  45         LOCK(lock);
  46         new->next = funcs;
  47         new->prev = 0;
  48         new->prepare = prepare;
  49         new->parent = parent;
  50         new->child = child;
  51         if (funcs) funcs->prev = new;
  52         funcs = new;
  53         UNLOCK(lock);
  54         return 0;
  55 }