74 lines
1.6 KiB
C
74 lines
1.6 KiB
C
#include <mqueue.h>
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#include <pthread.h>
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#include <errno.h>
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#include <sys/socket.h>
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#include <signal.h>
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#include <unistd.h>
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#include "syscall.h"
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struct args {
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pthread_barrier_t barrier;
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int sock;
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const struct sigevent *sev;
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};
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static void *start(void *p)
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{
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struct args *args = p;
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char buf[32];
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ssize_t n;
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int s = args->sock;
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void (*func)(union sigval) = args->sev->sigev_notify_function;
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union sigval val = args->sev->sigev_value;
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pthread_barrier_wait(&args->barrier);
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n = recv(s, buf, sizeof(buf), MSG_NOSIGNAL|MSG_WAITALL);
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close(s);
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if (n==sizeof buf && buf[sizeof buf - 1] == 1)
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func(val);
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return 0;
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}
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int mq_notify(mqd_t mqd, const struct sigevent *sev)
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{
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struct args args = { .sev = sev };
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pthread_attr_t attr;
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pthread_t td;
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int s;
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struct sigevent sev2;
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static const char zeros[32];
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if (!sev || sev->sigev_notify != SIGEV_THREAD)
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return syscall(SYS_mq_notify, mqd, sev);
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s = socket(AF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, 0);
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if (s < 0) return -1;
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args.sock = s;
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if (sev->sigev_notify_attributes) attr = *sev->sigev_notify_attributes;
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else pthread_attr_init(&attr);
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pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
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pthread_barrier_init(&args.barrier, 0, 2);
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if (pthread_create(&td, &attr, start, &args)) {
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__syscall(SYS_close, s);
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errno = EAGAIN;
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return -1;
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}
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pthread_barrier_wait(&args.barrier);
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pthread_barrier_destroy(&args.barrier);
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sev2.sigev_notify = SIGEV_THREAD;
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sev2.sigev_signo = s;
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sev2.sigev_value.sival_ptr = (void *)&zeros;
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if (syscall(SYS_mq_notify, mqd, &sev2) < 0) {
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pthread_cancel(td);
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__syscall(SYS_close, s);
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return -1;
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}
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return 0;
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}
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