1 #include <unistd.h>
2 #include <errno.h>
3 #include "libc.h"
4 #include "lock.h"
5 #include "pthread_impl.h"
6 #include "fork_impl.h"
7
8 static volatile int *const dummy_lockptr = 0;
9
10 weak_alias(dummy_lockptr, __at_quick_exit_lockptr);
11 weak_alias(dummy_lockptr, __atexit_lockptr);
12 weak_alias(dummy_lockptr, __dlerror_lockptr);
13 weak_alias(dummy_lockptr, __gettext_lockptr);
14 weak_alias(dummy_lockptr, __locale_lockptr);
15 weak_alias(dummy_lockptr, __random_lockptr);
16 weak_alias(dummy_lockptr, __sem_open_lockptr);
17 weak_alias(dummy_lockptr, __stdio_ofl_lockptr);
18 weak_alias(dummy_lockptr, __syslog_lockptr);
19 weak_alias(dummy_lockptr, __timezone_lockptr);
20 weak_alias(dummy_lockptr, __bump_lockptr);
21
22 weak_alias(dummy_lockptr, __vmlock_lockptr);
23
24 static volatile int *const *const atfork_locks[] = {
25 &__at_quick_exit_lockptr,
26 &__atexit_lockptr,
27 &__dlerror_lockptr,
28 &__gettext_lockptr,
29 &__locale_lockptr,
30 &__random_lockptr,
31 &__sem_open_lockptr,
32 &__stdio_ofl_lockptr,
33 &__syslog_lockptr,
34 &__timezone_lockptr,
35 &__bump_lockptr,
36 };
37
dummy(int x)38 static void dummy(int x) { }
39 weak_alias(dummy, __fork_handler);
40 weak_alias(dummy, __malloc_atfork);
41 weak_alias(dummy, __ldso_atfork);
42
dummy_0(void)43 static void dummy_0(void) { }
44 weak_alias(dummy_0, __tl_lock);
45 weak_alias(dummy_0, __tl_unlock);
46
fork(void)47 pid_t fork(void)
48 {
49 sigset_t set;
50 __fork_handler(-1);
51 __block_app_sigs(&set);
52 int need_locks = libc.need_locks > 0;
53 if (need_locks) {
54 __ldso_atfork(-1);
55 __inhibit_ptc();
56 for (int i=0; i<sizeof atfork_locks/sizeof *atfork_locks; i++)
57 if (*atfork_locks[i]) LOCK(*atfork_locks[i]);
58 __malloc_atfork(-1);
59 __tl_lock();
60 }
61 pthread_t self=__pthread_self(), next=self->next;
62 pid_t ret = _Fork();
63 int errno_save = errno;
64 if (need_locks) {
65 if (!ret) {
66 for (pthread_t td=next; td!=self; td=td->next)
67 td->tid = -1;
68 if (__vmlock_lockptr) {
69 __vmlock_lockptr[0] = 0;
70 __vmlock_lockptr[1] = 0;
71 }
72 }
73 __tl_unlock();
74 __malloc_atfork(!ret);
75 for (int i=0; i<sizeof atfork_locks/sizeof *atfork_locks; i++)
76 if (*atfork_locks[i])
77 if (ret) UNLOCK(*atfork_locks[i]);
78 else **atfork_locks[i] = 0;
79 __release_ptc();
80 __ldso_atfork(!ret);
81 }
82 __restore_sigs(&set);
83 __fork_handler(!ret);
84 if (ret<0) errno = errno_save;
85 return ret;
86 }
87