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shadow_file.c
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shadow_file.c
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/*
* Copyright (C) 2012 Taobao Inc.
*
* Liu Yuan <namei.unix@gmail.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* Sheepfs use this shadow file mechanism to mostly manage dentries. We
* might also make use of those shadow file to cache non-volatile states.
*/
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <sys/xattr.h>
#include <stdlib.h>
#include "util.h"
#include "sheepfs.h"
int shadow_file_read(const char *path, char *buf, size_t size, off_t offset)
{
char p[PATH_MAX];
int fd, len;
snprintf(p, sizeof(p), "%s%s", sheepfs_shadow, path);
fd = open(p, O_RDONLY);
if (fd < 0) {
sheepfs_pr("%m\n");
return -errno;
}
len = xpread(fd, buf, size, offset);
close(fd);
return len;
}
size_t shadow_file_write(const char *path, const char *buf, size_t size)
{
char p[PATH_MAX];
int fd;
size_t len = 0;
snprintf(p, sizeof(p), "%s%s", sheepfs_shadow, path);
fd = open(p, O_WRONLY | O_TRUNC);
if (fd < 0) {
sheepfs_pr("%m\n");
return 0;
}
len = xwrite(fd, buf, size);
if (len != size) {
sheepfs_pr("failed to write\n");
len = 0;
}
close(fd);
return len;
}
int shadow_file_create(const char *path)
{
char p[PATH_MAX];
int fd;
snprintf(p, sizeof(p), "%s%s", sheepfs_shadow, path);
fd = creat(p, 0644);
if (fd < 0) {
if (errno != EEXIST) {
sheepfs_pr("%m\n");
return -1;
}
}
close(fd);
return 0;
}
int shadow_dir_create(const char *path)
{
char p[PATH_MAX];
snprintf(p, sizeof(p), "%s%s", sheepfs_shadow, path);
if (xmkdir(p, 0755) < 0) {
sheepfs_pr("%m\n");
return -1;
}
return 0;
}
int shadow_dir_delete(const char *path)
{
char p[PATH_MAX];
snprintf(p, sizeof(p), "%s%s", sheepfs_shadow, path);
if (rmdir(p) < 0) {
sheepfs_pr("%m\n");
return -1;
}
return 0;
}
int shadow_file_setxattr(const char *path, const char *name,
const void *value, size_t size)
{
char p[PATH_MAX];
snprintf(p, sizeof(p), "%s%s", sheepfs_shadow, path);
if (setxattr(p, name, value, size, 0) < 0) {
sheepfs_pr("%m\n");
return -1;
}
return 0;
}
int shadow_file_getxattr(const char *path, const char *name,
void *value, size_t size)
{
char p[PATH_MAX];
snprintf(p, sizeof(p), "%s%s", sheepfs_shadow, path);
if (getxattr(p, name, value, size) < 0) {
sheepfs_pr("%m\n");
return -1;
}
return 0;
}
int shadow_file_delete(const char *path)
{
char p[PATH_MAX];
snprintf(p, sizeof(p), "%s%s", sheepfs_shadow, path);
if (unlink(p) < 0) {
if (errno != ENOENT) {
sheepfs_pr("%m\n");
return -1;
}
}
return 0;
}
bool shadow_file_exist(const char *path)
{
char p[PATH_MAX];
snprintf(p, sizeof(p), "%s%s", sheepfs_shadow, path);
if (access(p, R_OK | W_OK) < 0) {
if (errno != ENOENT)
sheepfs_pr("%m\n");
return false;
}
return true;
}
bool shadow_file_stat(const char *path, struct stat *st)
{
char p[PATH_MAX];
snprintf(p, sizeof(p), "%s%s", sheepfs_shadow, path);
if (stat(p, st) < 0) {
if (errno != ENOENT)
sheepfs_pr("%m\n");
return false;
}
return true;
}