btrfs-progs/props.c

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/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/xattr.h>
#include <fcntl.h>
#include <unistd.h>
#include <btrfsutil.h>
#include "kernel-shared/ctree.h"
#include "cmds/commands.h"
#include "common/utils.h"
#include "props.h"
#define XATTR_BTRFS_PREFIX "btrfs."
#define XATTR_BTRFS_PREFIX_LEN (sizeof(XATTR_BTRFS_PREFIX) - 1)
/*
* Defined as synonyms in attr/xattr.h
*/
#ifndef ENOATTR
#define ENOATTR ENODATA
#endif
static int prop_read_only(enum prop_object_type type,
const char *object,
const char *name,
const char *value)
{
enum btrfs_util_error err;
bool read_only;
if (value) {
if (!strcmp(value, "true")) {
read_only = true;
} else if (!strcmp(value, "false")) {
read_only = false;
} else {
error("invalid value for property: %s", value);
return -EINVAL;
}
err = btrfs_util_set_subvolume_read_only(object, read_only);
if (err) {
error_btrfs_util(err);
return -errno;
}
} else {
err = btrfs_util_get_subvolume_read_only(object, &read_only);
if (err) {
error_btrfs_util(err);
return -errno;
}
printf("ro=%s\n", read_only ? "true" : "false");
}
return 0;
}
static int prop_label(enum prop_object_type type,
const char *object,
const char *name,
const char *value)
{
int ret;
if (value) {
ret = set_label((char *) object, (char *) value);
} else {
char label[BTRFS_LABEL_SIZE];
ret = get_label((char *) object, label);
if (!ret)
fprintf(stdout, "label=%s\n", label);
}
return ret;
}
static int prop_compression(enum prop_object_type type,
const char *object,
const char *name,
const char *value)
{
int ret;
ssize_t sret;
int fd = -1;
DIR *dirstream = NULL;
char *buf = NULL;
char *xattr_name = NULL;
int open_flags = value ? O_RDWR : O_RDONLY;
fd = open_file_or_dir3(object, &dirstream, open_flags);
if (fd == -1) {
ret = -errno;
error("failed to open %s: %m", object);
goto out;
}
xattr_name = malloc(XATTR_BTRFS_PREFIX_LEN + strlen(name) + 1);
if (!xattr_name) {
ret = -ENOMEM;
goto out;
}
memcpy(xattr_name, XATTR_BTRFS_PREFIX, XATTR_BTRFS_PREFIX_LEN);
memcpy(xattr_name + XATTR_BTRFS_PREFIX_LEN, name, strlen(name));
xattr_name[XATTR_BTRFS_PREFIX_LEN + strlen(name)] = '\0';
if (value) {
if (strcmp(value, "no") == 0 || strcmp(value, "none") == 0)
value = "";
sret = fsetxattr(fd, xattr_name, value, strlen(value), 0);
} else {
sret = fgetxattr(fd, xattr_name, NULL, 0);
}
if (sret < 0) {
ret = -errno;
if (ret != -ENOATTR)
error("failed to %s compression for %s: %m",
value ? "set" : "get", object);
else
ret = 0;
goto out;
}
if (!value) {
size_t len = sret;
buf = malloc(len);
if (!buf) {
ret = -ENOMEM;
goto out;
}
sret = fgetxattr(fd, xattr_name, buf, len);
if (sret < 0) {
ret = -errno;
error("failed to get compression for %s: %m", object);
goto out;
}
fprintf(stdout, "compression=%.*s\n", (int)len, buf);
}
ret = 0;
out:
free(xattr_name);
free(buf);
if (fd >= 0)
close_file_or_dir(fd, dirstream);
return ret;
}
const struct prop_handler prop_handlers[] = {
{
.name ="ro",
.desc = "read-only status of a subvolume",
.read_only = 0,
.types = prop_object_subvol,
.handler = prop_read_only
},
{
.name = "label",
.desc = "label of the filesystem",
.read_only = 0,
.types = prop_object_dev | prop_object_root,
.handler = prop_label
},
{
.name = "compression",
.desc = "compression algorithm for the file or directory",
.read_only = 0,
.types = prop_object_inode, prop_compression
},
{NULL, NULL, 0, 0, NULL}
};