82 lines
2.0 KiB
C
82 lines
2.0 KiB
C
// See ../getdents/getdents.go for some info on why
|
|
// this exists.
|
|
|
|
#define _GNU_SOURCE
|
|
#include <fcntl.h>
|
|
#include <stdio.h>
|
|
#include <unistd.h>
|
|
#include <stdlib.h>
|
|
#include <stdint.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/syscall.h>
|
|
#include <errno.h>
|
|
#include <pthread.h>
|
|
|
|
static pthread_mutex_t mutex;
|
|
static int sum;
|
|
|
|
struct up {
|
|
pthread_mutex_t *my_mutex;
|
|
pthread_mutex_t *other_mutex;
|
|
int fd;
|
|
};
|
|
|
|
void *reader(void *arg) {
|
|
struct up* up = (struct up*)arg;
|
|
int fd = up->fd;
|
|
char tmp[10000];
|
|
while(1) {
|
|
pthread_mutex_lock(up->my_mutex);
|
|
int n = syscall(SYS_getdents64, fd, tmp, sizeof(tmp));
|
|
if (n > 0) {
|
|
printf("t%ld: n=%d\n", gettid(), n);
|
|
} else {
|
|
printf("t%ld: n=0 errno=%d total %d bytes\n", gettid(), errno, sum);
|
|
if (n < 0) {
|
|
exit(1);
|
|
}
|
|
pthread_mutex_unlock(up->other_mutex);
|
|
break;
|
|
}
|
|
sum += n;
|
|
pthread_mutex_unlock(up->other_mutex);
|
|
}
|
|
}
|
|
|
|
int main(int argc, char *argv[])
|
|
{
|
|
if(argc != 2) {
|
|
printf("Usage: %s PATH\n", argv[0]);
|
|
printf("Run getdents(2) on PATH in a 100ms loop\n");
|
|
exit(1);
|
|
}
|
|
|
|
const char *path = argv[1];
|
|
|
|
for (int i = 1 ; ; i ++ ) {
|
|
sum = 0;
|
|
int fd = open(path, O_RDONLY);
|
|
if (fd == -1) {
|
|
perror("open");
|
|
exit(1);
|
|
}
|
|
pthread_t reader1_thread, reader2_thread;
|
|
pthread_mutex_t m1 = PTHREAD_MUTEX_INITIALIZER, m2 = PTHREAD_MUTEX_INITIALIZER;
|
|
pthread_mutex_lock(&m2);
|
|
struct up up1, up2;
|
|
up1.fd = fd;
|
|
up1.my_mutex = &m1;
|
|
up1.other_mutex = &m2;
|
|
up2.fd = fd;
|
|
up2.my_mutex = &m2;
|
|
up2.other_mutex = &m1;
|
|
pthread_create(&reader1_thread, NULL, reader, &up1);
|
|
pthread_create(&reader2_thread, NULL, reader, &up2);
|
|
pthread_join(reader1_thread, NULL);
|
|
pthread_join(reader2_thread, NULL);
|
|
close(fd);
|
|
printf("---\n");
|
|
usleep(100000);
|
|
}
|
|
}
|