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, __gettext_lockptr);
13 weak_alias(dummy_lockptr, __locale_lockptr);
14 weak_alias(dummy_lockptr, __random_lockptr);
15 weak_alias(dummy_lockptr, __sem_open_lockptr);
16 weak_alias(dummy_lockptr, __stdio_ofl_lockptr);
17 weak_alias(dummy_lockptr, __syslog_lockptr);
18 weak_alias(dummy_lockptr, __timezone_lockptr);
19 weak_alias(dummy_lockptr, __bump_lockptr);
20
21 weak_alias(dummy_lockptr, __vmlock_lockptr);
22
23 static volatile int *const *const atfork_locks[] = {
24 &__at_quick_exit_lockptr,
25 &__atexit_lockptr,
26 &__gettext_lockptr,
27 &__locale_lockptr,
28 &__random_lockptr,
29 &__sem_open_lockptr,
30 &__stdio_ofl_lockptr,
31 &__syslog_lockptr,
32 &__timezone_lockptr,
33 &__bump_lockptr,
34 };
35
dummy(int x)36 static void dummy(int x) { }
37 weak_alias(dummy, __fork_handler);
38 weak_alias(dummy, __malloc_atfork);
39 weak_alias(dummy, __aio_atfork);
40 weak_alias(dummy, __pthread_key_atfork);
41 weak_alias(dummy, __ldso_atfork);
42 weak_alias(dummy, __pthread_mutex_unlock_atfork);
43
dummy_0(void)44 static void dummy_0(void) { }
45 weak_alias(dummy_0, __tl_lock);
46 weak_alias(dummy_0, __tl_unlock);
47
dummy_get_tl_lock_caller_count(void)48 static struct call_tl_lock *dummy_get_tl_lock_caller_count(void)
49 {
50 return NULL;
51 }
52
53 weak_alias(dummy_get_tl_lock_caller_count, get_tl_lock_caller_count);
54
fork(void)55 pid_t fork(void)
56 {
57 sigset_t set;
58 __fork_handler(-1);
59 __block_app_sigs(&set);
60 int need_locks = libc.need_locks > 0;
61 if (need_locks) {
62 __ldso_atfork(-1);
63 __pthread_key_atfork(-1);
64 __aio_atfork(-1);
65 __inhibit_ptc();
66 for (int i=0; i<sizeof atfork_locks/sizeof *atfork_locks; i++)
67 if (*atfork_locks[i]) LOCK(*atfork_locks[i]);
68 __malloc_atfork(-1);
69 __tl_lock();
70 if (get_tl_lock_caller_count()) {
71 get_tl_lock_caller_count()->fork_tl_lock++;
72 }
73 }
74 pthread_t self=__pthread_self(), next=self->next;
75 pid_t ret = _Fork();
76 int errno_save = errno;
77 if (need_locks) {
78 if (!ret) {
79 for (pthread_t td=next; td!=self; td=td->next)
80 td->tid = -1;
81 if (__vmlock_lockptr) {
82 __vmlock_lockptr[0] = 0;
83 __vmlock_lockptr[1] = 0;
84 }
85 }
86 if (get_tl_lock_caller_count()) {
87 get_tl_lock_caller_count()->fork_tl_lock--;
88 }
89 __tl_unlock();
90 __malloc_atfork(!ret);
91 for (int i=0; i<sizeof atfork_locks/sizeof *atfork_locks; i++)
92 if (*atfork_locks[i])
93 if (ret) UNLOCK(*atfork_locks[i]);
94 else **atfork_locks[i] = 0;
95 __release_ptc();
96 if (ret) __aio_atfork(0);
97 __pthread_key_atfork(!ret);
98 __ldso_atfork(!ret);
99 __pthread_mutex_unlock_atfork(ret);
100 }
101 __restore_sigs(&set);
102 __fork_handler(!ret);
103 if (ret<0) errno = errno_save;
104 return ret;
105 }
106