hardcoresushi/libgocryptfs
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getdents_c: read from two threads

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This was an attempt to make the C code more
similar to Go (which also reads from multiple threads).

However, I still could not repro the ENOENT problems.

https://github.com/rfjakob/gocryptfs/issues/483
This commit is contained in:
Jakob Unterwurzacher 2020-06-21 11:59:08 +02:00
parent 6aa9f5636f
commit 77632b7554
2 changed files with 50 additions and 17 deletions
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2
contrib/getdents-debug/getdents_c/Makefile
View File

@ -1,2 +1,2 @@
getdents_c: *.c Makefile
gcc getdents.c -o getdents_c
gcc getdents.c -lpthread -o getdents_c

65
contrib/getdents-debug/getdents_c/getdents.c
View File

@ -1,6 +1,7 @@
// See ../getdents/getdents.go for some info on why
// this exists.
#define _GNU_SOURCE
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
@ -9,6 +10,38 @@
#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[])
{
@ -21,28 +54,28 @@ int main(int argc, char *argv[])
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);
}
char tmp[10000];
int sum = 0;
printf("%3d: getdents64: ", i);
for ( ; ; ) {
int n = syscall(SYS_getdents64, fd, tmp, sizeof(tmp));
printf("n=%d; ", n);
if (n <= 0) {
printf("errno=%d total %d bytes\n", errno, sum);
if (n < 0) {
exit(1);
}
break;
}
sum += n;
}
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);
}
}