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v261
src/basic/chattr-util.c
254 строки
8 KB
Yu Watanabe
tree-wide: normalize comment style
15 дек 2025, 02:50
15 дек 2025, 02:50
9337814
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/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include <fcntl.h> #include <sys/ioctl.h> #include <sys/stat.h> #include "bitfield.h" #include "chattr-util.h" #include "errno-util.h" #include "fd-util.h" #include "fs-util.h" #include "log.h" #include "recurse-dir.h" #include "string-util.h" int chattr_full( int dir_fd, const char *path, unsigned value, unsigned mask, unsigned *ret_previous, unsigned *ret_final, ChattrApplyFlags flags) { _cleanup_close_ int fd = -EBADF; unsigned old_attr, new_attr; int set_flags_errno = 0; struct stat st; assert(dir_fd >= 0 || dir_fd == AT_FDCWD); fd = xopenat(dir_fd, path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); if (fd < 0) return fd; 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 (!inode_type_can_chattr(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_IS_IOCTL_NOT_SUPPORTED(errno) || !FLAGS_SET(flags, CHATTR_FALLBACK_BITWISE)) return -errno; /* When -EINVAL is returned, incompatible attributes might be 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. * * Alternatively, when we get EINVAL or 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; BIT_FOREACH(i, mask) { unsigned new_one, mask_one = 1u << i; 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_IS_IOCTL_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_IOCTL_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_IOCTL_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_IOCTL_NOT_SUPPORTED(set_flags_errno) ? set_flags_errno : -ENOANO; } int read_attr_fd(int fd, unsigned *ret) { struct stat st; assert(fd >= 0); assert(ret); if (fstat(fd, &st) < 0) return -errno; if (!inode_type_can_chattr(st.st_mode)) return -ENOTTY; _cleanup_close_ int fd_close = -EBADF; fd = fd_reopen_condition(fd, O_RDONLY|O_CLOEXEC|O_NOCTTY, O_PATH, &fd_close); /* drop O_PATH if it is set */ if (fd < 0) return fd; return RET_NERRNO(ioctl(fd, FS_IOC_GETFLAGS, ret)); } int read_attr_at(int dir_fd, const char *path, unsigned *ret) { _cleanup_close_ int fd_close = -EBADF; int fd; assert(dir_fd >= 0 || dir_fd == AT_FDCWD); assert(ret); if (isempty(path) && dir_fd != AT_FDCWD) fd = dir_fd; else { fd_close = xopenat(dir_fd, path, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); if (fd_close < 0) return fd_close; fd = fd_close; } return read_attr_fd(fd, ret); } int read_fs_xattr_fd(int fd, uint32_t *ret_xflags, uint32_t *ret_projid) { struct fsxattr attrs; _cleanup_close_ int fd_reopened = -EBADF; assert(fd >= 0); fd = fd_reopen_condition(fd, O_RDONLY|O_CLOEXEC|O_NOCTTY, O_PATH, &fd_reopened); if (fd < 0) return fd; if (ioctl(fd, FS_IOC_FSGETXATTR, &attrs) < 0) return -errno; if (ret_xflags) *ret_xflags = attrs.fsx_xflags; if (ret_projid) *ret_projid = attrs.fsx_projid; return 0; } int set_proj_id(int fd, uint32_t proj_id) { struct fsxattr attrs; _cleanup_close_ int fd_reopened = -EBADF; assert(fd >= 0); fd = fd_reopen_condition(fd, O_RDONLY|O_CLOEXEC|O_NOCTTY, O_PATH, &fd_reopened); if (fd < 0) return fd; if (ioctl(fd, FS_IOC_FSGETXATTR, &attrs) < 0) return -errno; struct stat statbuf; if (fstat(fd, &statbuf) < 0) return -errno; if (attrs.fsx_projid == proj_id && (!S_ISDIR(statbuf.st_mode) || FLAGS_SET(attrs.fsx_xflags, FS_XFLAG_PROJINHERIT))) return 0; attrs.fsx_projid = proj_id; if (S_ISDIR(statbuf.st_mode)) attrs.fsx_xflags |= FS_XFLAG_PROJINHERIT; return RET_NERRNO(ioctl(fd, FS_IOC_FSSETXATTR, &attrs)); } static int set_proj_id_cb( RecurseDirEvent event, const char *path, int dir_fd, int inode_fd, const struct dirent *de, const struct statx *sx, void *userdata) { if (!IN_SET(event, RECURSE_DIR_ENTER, RECURSE_DIR_ENTRY)) return RECURSE_DIR_CONTINUE; if (de && !IN_SET(de->d_type, DT_DIR, DT_REG)) return RECURSE_DIR_CONTINUE; return set_proj_id(inode_fd, PTR_TO_UINT32(userdata)); } int set_proj_id_recursive(int fd, uint32_t proj_id) { return recurse_dir_at( fd, /* path= */ NULL, /* statx_mask= */ 0, /* n_depth_max= */ UINT_MAX, RECURSE_DIR_ENSURE_TYPE|RECURSE_DIR_TOPLEVEL|RECURSE_DIR_INODE_FD, set_proj_id_cb, UINT32_TO_PTR(proj_id)); } bool inode_type_can_chattr(mode_t mode) { return IN_SET(mode & S_IFMT, S_IFREG, S_IFDIR); }