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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <errno.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <linux/fs.h>
#include "chattr-util.h"
#include "fd-util.h"
#include "macro.h"
int chattr_fd(int fd, unsigned value, unsigned mask, unsigned *previous) {
unsigned old_attr, new_attr;
struct stat st;
assert(fd >= 0);
if (fstat(fd, &st) < 0)
return -errno;
/* Explicitly check whether this is a regular file or
* directory. If it is anything else (such as a device node or
* fifo), then the ioctl will not hit the file systems but
* possibly drivers, where the ioctl might have different
* effects. Notably, DRM is using the same ioctl() number. */
if (!S_ISDIR(st.st_mode) && !S_ISREG(st.st_mode))
return -ENOTTY;
if (mask == 0 && !previous)
return 0;
if (ioctl(fd, FS_IOC_GETFLAGS, &old_attr) < 0)
return -errno;
new_attr = (old_attr & ~mask) | (value & mask);
if (new_attr == old_attr) {
if (previous)
*previous = old_attr;
return 0;
}
if (ioctl(fd, FS_IOC_SETFLAGS, &new_attr) < 0)
return -errno;
if (previous)
*previous = old_attr;
return 1;
}
int chattr_path(const char *p, unsigned value, unsigned mask, unsigned *previous) {
_cleanup_close_ int fd = -1;
assert(p);
if (mask == 0)
return 0;
fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd < 0)
return -errno;
return chattr_fd(fd, value, mask, previous);
}
int read_attr_fd(int fd, unsigned *ret) {
struct stat st;
assert(fd >= 0);
if (fstat(fd, &st) < 0)
return -errno;
if (!S_ISDIR(st.st_mode) && !S_ISREG(st.st_mode))
return -ENOTTY;
if (ioctl(fd, FS_IOC_GETFLAGS, ret) < 0)
return -errno;
return 0;
}
int read_attr_path(const char *p, unsigned *ret) {
_cleanup_close_ int fd = -1;
assert(p);
assert(ret);
fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
if (fd < 0)
return -errno;
return read_attr_fd(fd, ret);
}
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