| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <sys/ioctl.h> |
| #include <sys/stat.h> |
| #include <linux/fs.h> |
| |
| #include "chattr-util.h" |
| #include "errno-util.h" |
| #include "fd-util.h" |
| #include "macro.h" |
| #include "string-util.h" |
| |
| int chattr_full(const char *path, |
| int fd, |
| unsigned value, |
| unsigned mask, |
| unsigned *ret_previous, |
| unsigned *ret_final, |
| ChattrApplyFlags flags) { |
| |
| _cleanup_close_ int fd_will_close = -EBADF; |
| unsigned old_attr, new_attr; |
| int set_flags_errno = 0; |
| struct stat st; |
| |
| assert(path || fd >= 0); |
| |
| if (fd < 0) { |
| fd = fd_will_close = open(path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); |
| if (fd < 0) |
| return -errno; |
| } |
| |
| 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 && !ret_previous && !ret_final) |
| 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 (ret_previous) |
| *ret_previous = old_attr; |
| if (ret_final) |
| *ret_final = old_attr; |
| return 0; |
| } |
| |
| if (ioctl(fd, FS_IOC_SETFLAGS, &new_attr) >= 0) { |
| unsigned attr; |
| |
| /* Some filesystems (BTRFS) silently fail when a flag cannot be set. Let's make sure our |
| * changes actually went through by querying the flags again and verifying they're equal to |
| * the flags we tried to configure. */ |
| |
| if (ioctl(fd, FS_IOC_GETFLAGS, &attr) < 0) |
| return -errno; |
| |
| if (new_attr == attr) { |
| if (ret_previous) |
| *ret_previous = old_attr; |
| if (ret_final) |
| *ret_final = new_attr; |
| return 1; |
| } |
| |
| /* Trigger the fallback logic. */ |
| errno = EINVAL; |
| } |
| |
| if ((errno != EINVAL && !ERRNO_IS_NOT_SUPPORTED(errno)) || |
| !FLAGS_SET(flags, CHATTR_FALLBACK_BITWISE)) |
| return -errno; |
| |
| /* When -EINVAL is returned, we assume that incompatible attributes are simultaneously |
| * specified. E.g., compress(c) and nocow(C) attributes cannot be set to files on btrfs. |
| * As a fallback, let's try to set attributes one by one. |
| * |
| * Also, when we get EOPNOTSUPP (or a similar error code) we assume a flag might just not be |
| * supported, and we can ignore it too */ |
| |
| unsigned current_attr = old_attr; |
| for (unsigned i = 0; i < sizeof(unsigned) * 8; i++) { |
| unsigned new_one, mask_one = 1u << i; |
| |
| if (!FLAGS_SET(mask, mask_one)) |
| continue; |
| |
| new_one = UPDATE_FLAG(current_attr, mask_one, FLAGS_SET(value, mask_one)); |
| if (new_one == current_attr) |
| continue; |
| |
| if (ioctl(fd, FS_IOC_SETFLAGS, &new_one) < 0) { |
| if (errno != EINVAL && !ERRNO_IS_NOT_SUPPORTED(errno)) |
| return -errno; |
| |
| log_full_errno(FLAGS_SET(flags, CHATTR_WARN_UNSUPPORTED_FLAGS) ? LOG_WARNING : LOG_DEBUG, |
| errno, |
| "Unable to set file attribute 0x%x on %s, ignoring: %m", mask_one, strna(path)); |
| |
| /* Ensures that we record whether only EOPNOTSUPP&friends are encountered, or if a more serious |
| * error (thus worth logging at a different level, etc) was seen too. */ |
| if (set_flags_errno == 0 || !ERRNO_IS_NOT_SUPPORTED(errno)) |
| set_flags_errno = -errno; |
| |
| continue; |
| } |
| |
| if (ioctl(fd, FS_IOC_GETFLAGS, ¤t_attr) < 0) |
| return -errno; |
| } |
| |
| if (ret_previous) |
| *ret_previous = old_attr; |
| if (ret_final) |
| *ret_final = current_attr; |
| |
| /* -ENOANO indicates that some attributes cannot be set. ERRNO_IS_NOT_SUPPORTED indicates that all |
| * encountered failures were due to flags not supported by the FS, so return a specific error in |
| * that case, so callers can handle it properly (e.g.: tmpfiles.d can use debug level logging). */ |
| return current_attr == new_attr ? 1 : ERRNO_IS_NOT_SUPPORTED(set_flags_errno) ? set_flags_errno : -ENOANO; |
| } |
| |
| 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; |
| |
| return RET_NERRNO(ioctl(fd, FS_IOC_GETFLAGS, ret)); |
| } |
| |
| int read_attr_path(const char *p, unsigned *ret) { |
| _cleanup_close_ int fd = -EBADF; |
| |
| 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); |
| } |