1 #include <time.h>
2 #include <setjmp.h>
3 #include <limits.h>
4 #include "pthread_impl.h"
5 #include "atomic.h"
6
7 struct ksigevent {
8 union sigval sigev_value;
9 int sigev_signo;
10 int sigev_notify;
11 int sigev_tid;
12 };
13
14 struct start_args {
15 volatile int b;
16 struct sigevent *sev;
17 };
18
19 /*
20 * barrier val:
21 * 0: init state
22 * 2: child thread arrive: when child thread is the first thread to arrive, will wait, otherwise, will wake
23 * 3: parent thread arrive: when parent thread is the first thread to arrive, will wait, otherwise, will wake
24 * 4: parent thread should wait for the child to finish synchronizing (state: CHILD_DONE)
25 * 5: child thread done
26 */
27 enum ThreadState {
28 INIT_STATE = 0,
29 CHILD_ARRIVE = 2,
30 PARENT_ARRIVE,
31 PARENT_WAIT,
32 CHILD_DONE,
33 };
34
dummy_0null35 static void dummy_0()
36 {
37 }
38 weak_alias(dummy_0, __pthread_tsd_run_dtors);
39
cleanup_fromsig(void *p)40 static void cleanup_fromsig(void *p)
41 {
42 pthread_t self = __pthread_self();
43 __pthread_tsd_run_dtors();
44 #ifdef FEATURE_PTHREAD_CANCEL
45 self->cancel = 0;
46 self->canceldisable = 0;
47 self->cancelasync = 0;
48 #endif
49 self->cancelbuf = 0;
50 __reset_tls();
51 longjmp(p, 1);
52 }
53
__child_sync(volatile int *barrier)54 static void __child_sync(volatile int *barrier)
55 {
56 if (a_swap(barrier, CHILD_ARRIVE) == INIT_STATE) {
57 __wait(barrier, 0, CHILD_ARRIVE, 0);
58 } else {
59 __wake(barrier, 1, 0);
60 }
61
62 a_swap(barrier, CHILD_DONE);
63 __wake(barrier, 1, 0);
64 }
65
__parent_sync(volatile int *barrier)66 static void __parent_sync(volatile int *barrier)
67 {
68 if (a_swap(barrier, PARENT_ARRIVE) == CHILD_ARRIVE) {
69 __wake(barrier, 1, 0);
70 } else {
71 __wait(barrier, 0, PARENT_ARRIVE, 0);
72 }
73
74 if (a_swap(barrier, PARENT_WAIT) != CHILD_DONE) {
75 __wait(barrier, 0, PARENT_WAIT, 0);
76 }
77 }
78
start(void *arg)79 static void *start(void *arg)
80 {
81 pthread_t self = __pthread_self();
82 struct start_args *args = arg;
83 jmp_buf jb;
84
85 void (*notify)(union sigval) = args->sev->sigev_notify_function;
86 union sigval val = args->sev->sigev_value;
87
88 __child_sync(&args->b);
89 #ifdef FEATURE_PTHREAD_CANCEL
90 if (self->cancel)
91 return 0;
92 #endif
93 for (;;) {
94 siginfo_t si;
95 while (sigwaitinfo(SIGTIMER_SET, &si) < 0);
96 if (si.si_code == SI_TIMER && !setjmp(jb)) {
97 #ifndef HWASAN_REMOVE_CLEANUP
98 pthread_cleanup_push(cleanup_fromsig, jb);
99 #endif
100 notify(val);
101 #ifndef HWASAN_REMOVE_CLEANUP
102 pthread_cleanup_pop(1);
103 #endif
104 }
105 if (self->timer_id < 0) break;
106 }
107 __syscall(SYS_timer_delete, self->timer_id & INT_MAX);
108 return 0;
109 }
110
timer_create(clockid_t clk, struct sigevent *restrict evp, timer_t *restrict res)111 int timer_create(clockid_t clk, struct sigevent *restrict evp, timer_t *restrict res)
112 {
113 static volatile int init = 0;
114 pthread_t td;
115 pthread_attr_t attr;
116 int r;
117 struct start_args args;
118 struct ksigevent ksev, *ksevp=0;
119 int timerid;
120 sigset_t set;
121
122 switch (evp ? evp->sigev_notify : SIGEV_SIGNAL) {
123 case SIGEV_NONE:
124 case SIGEV_SIGNAL:
125 case SIGEV_THREAD_ID:
126 if (evp) {
127 ksev.sigev_value = evp->sigev_value;
128 ksev.sigev_signo = evp->sigev_signo;
129 ksev.sigev_notify = evp->sigev_notify;
130 if (evp->sigev_notify == SIGEV_THREAD_ID)
131 ksev.sigev_tid = evp->sigev_notify_thread_id;
132 else
133 ksev.sigev_tid = 0;
134 ksevp = &ksev;
135 }
136 if (syscall(SYS_timer_create, clk, ksevp, &timerid) < 0)
137 return -1;
138 *res = (void *)(intptr_t)timerid;
139 break;
140 case SIGEV_THREAD:
141 if (!init) {
142 struct sigaction sa = { .sa_handler = SIG_DFL };
143 __libc_sigaction(SIGTIMER, &sa, 0);
144 a_store(&init, 1);
145 }
146 if (evp->sigev_notify_attributes)
147 attr = *evp->sigev_notify_attributes;
148 else
149 pthread_attr_init(&attr);
150 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
151 a_store(&args.b, 0);
152 args.sev = evp;
153
154 __block_app_sigs(&set);
155 __syscall(SYS_rt_sigprocmask, SIG_BLOCK, SIGTIMER_SET, 0, _NSIG/8);
156 r = pthread_create(&td, &attr, start, &args);
157 __restore_sigs(&set);
158 if (r) {
159 errno = r;
160 return -1;
161 }
162
163 ksev.sigev_value.sival_ptr = 0;
164 ksev.sigev_signo = SIGTIMER;
165 ksev.sigev_notify = SIGEV_THREAD_ID;
166 ksev.sigev_tid = td->tid;
167 if (syscall(SYS_timer_create, clk, &ksev, &timerid) < 0) {
168 timerid = -1;
169 #ifdef FEATURE_PTHREAD_CANCEL
170 td->cancel = 1;
171 #endif
172 }
173 td->timer_id = timerid;
174 __parent_sync(&args.b);
175 if (timerid < 0) return -1;
176 *res = (void *)(INTPTR_MIN | (uintptr_t)td>>1);
177 break;
178 default:
179 errno = EINVAL;
180 return -1;
181 }
182
183 return 0;
184 }
185