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| 1 | +#include <pthread.h> |
| 2 | +#include <stdatomic.h> |
| 3 | +#include <stdio.h> |
| 4 | +#include <sys/mman.h> |
| 5 | +#include <sys/wait.h> |
| 6 | +#include <unistd.h> |
| 7 | + |
| 8 | +int main() { |
| 9 | + int ws; |
| 10 | + FILE *f; |
| 11 | + pid_t pid; |
| 12 | + pthread_condattr_t ca; |
| 13 | + pthread_mutexattr_t ma; |
| 14 | + struct Shared { |
| 15 | + atomic_int state; |
| 16 | + pthread_cond_t cond; |
| 17 | + pthread_mutex_t lock; |
| 18 | + } *s; |
| 19 | + if (!(f = tmpfile())) |
| 20 | + return 0; |
| 21 | + if (ftruncate(fileno(f), 512)) |
| 22 | + return 1; |
| 23 | + if ((s = (struct Shared *)mmap(0, 512, PROT_READ | PROT_WRITE, |
| 24 | + MAP_SHARED | MAP_ANONYMOUS, -1, 0)) == |
| 25 | + MAP_FAILED) |
| 26 | + return 2; |
| 27 | + if (pthread_condattr_init(&ca)) |
| 28 | + return 3; |
| 29 | + if (pthread_mutexattr_init(&ma)) |
| 30 | + return 4; |
| 31 | + if (pthread_condattr_setpshared(&ca, PTHREAD_PROCESS_SHARED)) |
| 32 | + return 5; |
| 33 | + if (pthread_mutexattr_setpshared(&ma, PTHREAD_PROCESS_SHARED)) |
| 34 | + return 6; |
| 35 | + if (pthread_cond_init(&s->cond, &ca)) |
| 36 | + return 7; |
| 37 | + if (pthread_mutex_init(&s->lock, &ma)) |
| 38 | + return 8; |
| 39 | + if (pthread_mutexattr_destroy(&ma)) |
| 40 | + return 9; |
| 41 | + if (pthread_condattr_destroy(&ca)) |
| 42 | + return 10; |
| 43 | + if ((pid = fork()) == -1) |
| 44 | + return 11; |
| 45 | + if (!pid) { |
| 46 | + alarm(2); |
| 47 | + if (pthread_mutex_lock(&s->lock)) |
| 48 | + return 12; |
| 49 | + s->state = 1; |
| 50 | + if (pthread_cond_wait(&s->cond, &s->lock)) |
| 51 | + return 13; |
| 52 | + if (pthread_mutex_unlock(&s->lock)) |
| 53 | + return 14; |
| 54 | + for (;;) |
| 55 | + if (s->state == 2) |
| 56 | + break; |
| 57 | + if (pthread_mutex_lock(&s->lock)) |
| 58 | + return 15; |
| 59 | + if (pthread_cond_signal(&s->cond)) |
| 60 | + return 16; |
| 61 | + if (pthread_mutex_unlock(&s->lock)) |
| 62 | + return 17; |
| 63 | + _exit(0); |
| 64 | + } |
| 65 | + alarm(2); |
| 66 | + for (;;) |
| 67 | + if (s->state == 1) |
| 68 | + break; |
| 69 | + if (pthread_mutex_lock(&s->lock)) |
| 70 | + return 18; |
| 71 | + if (pthread_cond_signal(&s->cond)) |
| 72 | + return 19; |
| 73 | + if (pthread_mutex_unlock(&s->lock)) |
| 74 | + return 20; |
| 75 | + if (pthread_mutex_lock(&s->lock)) |
| 76 | + return 21; |
| 77 | + s->state = 2; |
| 78 | + if (pthread_cond_wait(&s->cond, &s->lock)) |
| 79 | + return 22; |
| 80 | + if (pthread_mutex_unlock(&s->lock)) |
| 81 | + return 23; |
| 82 | + if (wait(&ws) != pid) |
| 83 | + return 24; |
| 84 | + if (!WIFEXITED(ws)) |
| 85 | + return 25; |
| 86 | + if (WEXITSTATUS(ws)) |
| 87 | + return 26; |
| 88 | + if (pthread_mutex_destroy(&s->lock)) |
| 89 | + return 27; |
| 90 | + if (pthread_cond_destroy(&s->cond)) |
| 91 | + return 28; |
| 92 | + return 0; |
| 93 | +} |
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