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#include <camellia/flags.h>
#include <camellia/syscalls.h>
#include <stdlib.h>
#include <unistd.h>
#include <esemaphore.h>
void esem_signal(struct evil_sem *sem) {
_sys_write(sem->signal, NULL, 0, 0, 0);
}
void esem_wait(struct evil_sem *sem) {
_sys_read(sem->wait, NULL, 0, 0);
}
struct evil_sem *esem_new(int value) {
hid_t ends_wait[2], ends_signal[2];
struct evil_sem *sem;
if (value < 0) return NULL;
if (_sys_pipe(ends_wait, 0) < 0) return NULL;
if (_sys_pipe(ends_signal, 0) < 0) goto fail_signal;
if (!(sem = malloc(sizeof *sem))) goto fail_malloc;
if (!_sys_fork(FORK_NOREAP, NULL)) {
close(ends_signal[1]);
while (_sys_read(ends_signal[0], NULL, 0, 0) >= 0) {
if (!_sys_fork(FORK_NOREAP, NULL)) {
_sys_write(ends_wait[1], NULL, 0, 0, 0);
exit(0);
}
}
exit(0);
}
close(ends_signal[0]);
close(ends_wait[1]);
sem->wait = ends_wait[0];
sem->signal = ends_signal[1];
while (value--) esem_signal(sem);
return sem;
fail_malloc:
close(ends_signal[0]);
close(ends_signal[1]);
fail_signal:
close(ends_wait[0]);
close(ends_wait[1]);
return NULL;
}
void esem_free(struct evil_sem *sem) {
close(sem->wait);
close(sem->signal);
free(sem);
}
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