1 #include <mqueue.h>
2 #include <pthread.h>
3 #include <errno.h>
4 #include <sys/socket.h>
5 #include <signal.h>
6 #include <unistd.h>
7 #include "syscall.h"
8 #include "pthread_impl.h"
9
10 struct args {
11 pthread_barrier_t barrier;
12 int sock;
13 const struct sigevent *sev;
14 };
15
start(void * p)16 static void *start(void *p)
17 {
18 struct args *args = p;
19 char buf[32];
20 ssize_t n;
21 int s = args->sock;
22 void (*func)(union sigval) = args->sev->sigev_notify_function;
23 union sigval val = args->sev->sigev_value;
24
25 pthread_barrier_wait(&args->barrier);
26 n = recv(s, buf, sizeof(buf), MSG_NOSIGNAL|MSG_WAITALL);
27 close(s);
28 if (n==sizeof buf && buf[sizeof buf - 1] == 1)
29 func(val);
30 return 0;
31 }
32
mq_notify(mqd_t mqd,const struct sigevent * sev)33 int mq_notify(mqd_t mqd, const struct sigevent *sev)
34 {
35 struct args args = { .sev = sev };
36 pthread_attr_t attr;
37 pthread_t td;
38 int s;
39 struct sigevent sev2;
40 static const char zeros[32];
41
42 if (!sev || sev->sigev_notify != SIGEV_THREAD)
43 return syscall(SYS_mq_notify, mqd, sev);
44
45 s = socket(AF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, 0);
46 if (s < 0) return -1;
47 args.sock = s;
48
49 if (sev->sigev_notify_attributes) attr = *sev->sigev_notify_attributes;
50 else pthread_attr_init(&attr);
51 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
52 pthread_barrier_init(&args.barrier, 0, 2);
53
54 if (pthread_create(&td, &attr, start, &args)) {
55 __syscall(SYS_close, s);
56 errno = EAGAIN;
57 return -1;
58 }
59
60 pthread_barrier_wait(&args.barrier);
61 pthread_barrier_destroy(&args.barrier);
62
63 sev2.sigev_notify = SIGEV_THREAD;
64 sev2.sigev_signo = s;
65 sev2.sigev_value.sival_ptr = (void *)&zeros;
66
67 if (syscall(SYS_mq_notify, mqd, &sev2) < 0) {
68 #ifdef FEATURE_PTHREAD_CANCEL
69 pthread_cancel(td);
70 #else
71 __syscall(SYS_tkill, td->tid, SIGCANCEL);
72 #endif
73 __syscall(SYS_close, s);
74 return -1;
75 }
76
77 return 0;
78 }
79