/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include #include #include #include #include #include #include #include #include #include "alloc-util.h" #include "btrfs-util.h" #include "chattr-util.h" #include "copy.h" #include "dirent-util.h" #include "fd-util.h" #include "fileio.h" #include "fs-util.h" #include "io-util.h" #include "macro.h" #include "missing_fs.h" #include "missing_syscall.h" #include "mkdir-label.h" #include "mountpoint-util.h" #include "nulstr-util.h" #include "rm-rf.h" #include "selinux-util.h" #include "signal-util.h" #include "stat-util.h" #include "stdio-util.h" #include "string-util.h" #include "strv.h" #include "sync-util.h" #include "time-util.h" #include "tmpfile-util.h" #include "umask-util.h" #include "user-util.h" #include "xattr-util.h" #define COPY_BUFFER_SIZE (16U*1024U) /* A safety net for descending recursively into file system trees to copy. On Linux PATH_MAX is 4096, which means the * deepest valid path one can build is around 2048, which we hence use as a safety net here, to not spin endlessly in * case of bind mount cycles and suchlike. */ #define COPY_DEPTH_MAX 2048U static ssize_t try_copy_file_range( int fd_in, loff_t *off_in, int fd_out, loff_t *off_out, size_t len, unsigned flags) { static int have = -1; ssize_t r; if (have == 0) return -ENOSYS; r = copy_file_range(fd_in, off_in, fd_out, off_out, len, flags); if (have < 0) have = r >= 0 || errno != ENOSYS; if (r < 0) return -errno; return r; } enum { FD_IS_NO_PIPE, FD_IS_BLOCKING_PIPE, FD_IS_NONBLOCKING_PIPE, }; static int fd_is_nonblock_pipe(int fd) { struct stat st; int flags; /* Checks whether the specified file descriptor refers to a pipe, and if so if O_NONBLOCK is set. */ if (fstat(fd, &st) < 0) return -errno; if (!S_ISFIFO(st.st_mode)) return FD_IS_NO_PIPE; flags = fcntl(fd, F_GETFL); if (flags < 0) return -errno; return FLAGS_SET(flags, O_NONBLOCK) ? FD_IS_NONBLOCKING_PIPE : FD_IS_BLOCKING_PIPE; } static int look_for_signals(CopyFlags copy_flags) { int r; if ((copy_flags & (COPY_SIGINT|COPY_SIGTERM)) == 0) return 0; r = pop_pending_signal(copy_flags & COPY_SIGINT ? SIGINT : 0, copy_flags & COPY_SIGTERM ? SIGTERM : 0); if (r < 0) return r; if (r != 0) return log_debug_errno(SYNTHETIC_ERRNO(EINTR), "Got %s, cancelling copy operation.", signal_to_string(r)); return 0; } static int create_hole(int fd, off_t size) { off_t offset; off_t end; offset = lseek(fd, 0, SEEK_CUR); if (offset < 0) return -errno; end = lseek(fd, 0, SEEK_END); if (end < 0) return -errno; /* If we're not at the end of the target file, try to punch a hole in the existing space using fallocate(). */ if (offset < end && fallocate(fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE, offset, MIN(size, end - offset)) < 0 && !ERRNO_IS_NOT_SUPPORTED(errno)) return -errno; if (end - offset >= size) { /* If we've created the full hole, set the file pointer to the end of the hole we created and exit. */ if (lseek(fd, offset + size, SEEK_SET) < 0) return -errno; return 0; } /* If we haven't created the full hole, use ftruncate() to grow the file (and the hole) to the * required size and move the file pointer to the end of the file. */ size -= end - offset; if (ftruncate(fd, end + size) < 0) return -errno; if (lseek(fd, 0, SEEK_END) < 0) return -errno; return 0; } int copy_bytes_full( int fdf, int fdt, uint64_t max_bytes, CopyFlags copy_flags, void **ret_remains, size_t *ret_remains_size, copy_progress_bytes_t progress, void *userdata) { _cleanup_close_ int fdf_opened = -EBADF, fdt_opened = -EBADF; bool try_cfr = true, try_sendfile = true, try_splice = true, copied_something = false; int r, nonblock_pipe = -1; size_t m = SSIZE_MAX; /* that is the maximum that sendfile and c_f_r accept */ assert(fdf >= 0); assert(fdt >= 0); assert(!FLAGS_SET(copy_flags, COPY_LOCK_BSD)); /* Tries to copy bytes from the file descriptor 'fdf' to 'fdt' in the smartest possible way. Copies a maximum * of 'max_bytes', which may be specified as UINT64_MAX, in which no maximum is applied. Returns negative on * error, zero if EOF is hit before the bytes limit is hit and positive otherwise. If the copy fails for some * reason but we read but didn't yet write some data an ret_remains/ret_remains_size is not NULL, then it will * be initialized with an allocated buffer containing this "remaining" data. Note that these two parameters are * initialized with a valid buffer only on failure and only if there's actually data already read. Otherwise * these parameters if non-NULL are set to NULL. */ if (ret_remains) *ret_remains = NULL; if (ret_remains_size) *ret_remains_size = 0; fdf = fd_reopen_condition(fdf, O_CLOEXEC | O_NOCTTY | O_RDONLY, O_PATH, &fdf_opened); if (fdf < 0) return fdf; fdt = fd_reopen_condition(fdt, O_CLOEXEC | O_NOCTTY | O_RDWR, O_PATH, &fdt_opened); if (fdt < 0) return fdt; /* Try btrfs reflinks first. This only works on regular, seekable files, hence let's check the file offsets of * source and destination first. */ if ((copy_flags & COPY_REFLINK)) { off_t foffset; foffset = lseek(fdf, 0, SEEK_CUR); if (foffset >= 0) { off_t toffset; toffset = lseek(fdt, 0, SEEK_CUR); if (toffset >= 0) { if (foffset == 0 && toffset == 0 && max_bytes == UINT64_MAX) r = reflink(fdf, fdt); /* full file reflink */ else r = reflink_range(fdf, foffset, fdt, toffset, max_bytes == UINT64_MAX ? 0 : max_bytes); /* partial reflink */ if (r >= 0) { off_t t; int ret; /* This worked, yay! Now — to be fully correct — let's adjust the file pointers */ if (max_bytes == UINT64_MAX) { /* We cloned to the end of the source file, let's position the read * pointer there, and query it at the same time. */ t = lseek(fdf, 0, SEEK_END); if (t < 0) return -errno; if (t < foffset) return -ESPIPE; /* Let's adjust the destination file write pointer by the same number * of bytes. */ t = lseek(fdt, toffset + (t - foffset), SEEK_SET); if (t < 0) return -errno; if (FLAGS_SET(copy_flags, COPY_VERIFY_LINKED)) { r = fd_verify_linked(fdf); if (r < 0) return r; } /* We copied the whole thing, hence hit EOF, return 0. */ ret = 0; } else { t = lseek(fdf, foffset + max_bytes, SEEK_SET); if (t < 0) return -errno; t = lseek(fdt, toffset + max_bytes, SEEK_SET); if (t < 0) return -errno; /* We copied only some number of bytes, which worked, but * this means we didn't hit EOF, return 1. */ ret = 1; } if (FLAGS_SET(copy_flags, COPY_VERIFY_LINKED)) { r = fd_verify_linked(fdf); if (r < 0) return r; } return ret; } } } } for (;;) { ssize_t n; if (max_bytes <= 0) break; r = look_for_signals(copy_flags); if (r < 0) return r; if (max_bytes != UINT64_MAX && m > max_bytes) m = max_bytes; if (copy_flags & COPY_HOLES) { off_t c, e; c = lseek(fdf, 0, SEEK_CUR); if (c < 0) return -errno; /* To see if we're in a hole, we search for the next data offset. */ e = lseek(fdf, c, SEEK_DATA); if (e < 0 && errno == ENXIO) /* If errno == ENXIO, that means we've reached the final hole of the file and * that hole isn't followed by more data. */ e = lseek(fdf, 0, SEEK_END); if (e < 0) return -errno; /* If we're in a hole (current offset is not a data offset), create a hole of the * same size in the target file. */ if (e > c) { /* Make sure our new hole doesn't go over the maximum size we're allowed to copy. */ n = MIN(max_bytes, (uint64_t) e - c); r = create_hole(fdt, n); if (r < 0) return r; /* Make sure holes are taken into account in the maximum size we're supposed to copy. */ if (max_bytes != UINT64_MAX) { max_bytes -= n; if (max_bytes <= 0) break; } /* Update the size we're supposed to copy in this iteration if needed. */ if (m > max_bytes) m = max_bytes; } c = e; /* Set c to the start of the data segment. */ /* After copying a potential hole, find the end of the data segment by looking for * the next hole. If we get ENXIO, we're at EOF. */ e = lseek(fdf, c, SEEK_HOLE); if (e < 0) { if (errno == ENXIO) break; return -errno; } /* SEEK_HOLE modifies the file offset so we need to move back to the initial offset. */ if (lseek(fdf, c, SEEK_SET) < 0) return -errno; /* Make sure we're not copying more than the current data segment. */ m = MIN(m, (size_t) e - c); } /* First try copy_file_range(), unless we already tried */ if (try_cfr) { n = try_copy_file_range(fdf, NULL, fdt, NULL, m, 0u); if (n < 0) { if (!IN_SET(n, -EINVAL, -ENOSYS, -EXDEV, -EBADF, -EOPNOTSUPP)) return n; try_cfr = false; /* use fallback below */ } else if (n == 0) { /* likely EOF */ if (copied_something) break; /* So, we hit EOF immediately, without having copied a single byte. This * could indicate two things: the file is actually empty, or we are on some * virtual file system such as procfs/sysfs where the syscall actually * doesn't work but doesn't return an error. Try to handle that, by falling * back to simple read()s in case we encounter empty files. * * See: https://lwn.net/Articles/846403/ */ try_cfr = try_sendfile = try_splice = false; } else /* Success! */ goto next; } /* First try sendfile(), unless we already tried */ if (try_sendfile) { n = sendfile(fdt, fdf, NULL, m); if (n < 0) { if (!IN_SET(errno, EINVAL, ENOSYS)) return -errno; try_sendfile = false; /* use fallback below */ } else if (n == 0) { /* likely EOF */ if (copied_something) break; try_sendfile = try_splice = false; /* same logic as above for copy_file_range() */ } else /* Success! */ goto next; } /* Then try splice, unless we already tried. */ if (try_splice) { /* splice()'s asynchronous I/O support is a bit weird. When it encounters a pipe file * descriptor, then it will ignore its O_NONBLOCK flag and instead only honour the * SPLICE_F_NONBLOCK flag specified in its flag parameter. Let's hide this behaviour * here, and check if either of the specified fds are a pipe, and if so, let's pass * the flag automatically, depending on O_NONBLOCK being set. * * Here's a twist though: when we use it to move data between two pipes of which one * has O_NONBLOCK set and the other has not, then we have no individual control over * O_NONBLOCK behaviour. Hence in that case we can't use splice() and still guarantee * systematic O_NONBLOCK behaviour, hence don't. */ if (nonblock_pipe < 0) { int a, b; /* Check if either of these fds is a pipe, and if so non-blocking or not */ a = fd_is_nonblock_pipe(fdf); if (a < 0) return a; b = fd_is_nonblock_pipe(fdt); if (b < 0) return b; if ((a == FD_IS_NO_PIPE && b == FD_IS_NO_PIPE) || (a == FD_IS_BLOCKING_PIPE && b == FD_IS_NONBLOCKING_PIPE) || (a == FD_IS_NONBLOCKING_PIPE && b == FD_IS_BLOCKING_PIPE)) /* splice() only works if one of the fds is a pipe. If neither is, * let's skip this step right-away. As mentioned above, if one of the * two fds refers to a blocking pipe and the other to a non-blocking * pipe, we can't use splice() either, hence don't try either. This * hence means we can only use splice() if either only one of the two * fds is a pipe, or if both are pipes with the same nonblocking flag * setting. */ try_splice = false; else nonblock_pipe = a == FD_IS_NONBLOCKING_PIPE || b == FD_IS_NONBLOCKING_PIPE; } } if (try_splice) { n = splice(fdf, NULL, fdt, NULL, m, nonblock_pipe ? SPLICE_F_NONBLOCK : 0); if (n < 0) { if (!IN_SET(errno, EINVAL, ENOSYS)) return -errno; try_splice = false; /* use fallback below */ } else if (n == 0) { /* likely EOF */ if (copied_something) break; try_splice = false; /* same logic as above for copy_file_range() + sendfile() */ } else /* Success! */ goto next; } /* As a fallback just copy bits by hand */ { uint8_t buf[MIN(m, COPY_BUFFER_SIZE)], *p = buf; ssize_t z; n = read(fdf, buf, sizeof buf); if (n < 0) return -errno; if (n == 0) /* EOF */ break; z = (size_t) n; do { ssize_t k; k = write(fdt, p, z); if (k < 0) { r = -errno; if (ret_remains) { void *copy; copy = memdup(p, z); if (!copy) return -ENOMEM; *ret_remains = copy; } if (ret_remains_size) *ret_remains_size = z; return r; } assert(k <= z); z -= k; p += k; } while (z > 0); } next: if (progress) { r = progress(n, userdata); if (r < 0) return r; } if (max_bytes != UINT64_MAX) { assert(max_bytes >= (uint64_t) n); max_bytes -= n; } /* sendfile accepts at most SSIZE_MAX-offset bytes to copy, so reduce our maximum by the * amount we already copied, but don't go below our copy buffer size, unless we are close the * limit of bytes we are allowed to copy. */ m = MAX(MIN(COPY_BUFFER_SIZE, max_bytes), m - n); copied_something = true; } if (FLAGS_SET(copy_flags, COPY_VERIFY_LINKED)) { r = fd_verify_linked(fdf); if (r < 0) return r; } if (copy_flags & COPY_TRUNCATE) { off_t off = lseek(fdt, 0, SEEK_CUR); if (off < 0) return -errno; if (ftruncate(fdt, off) < 0) return -errno; } return max_bytes <= 0; /* return 0 if we hit EOF earlier than the size limit */ } static int fd_copy_symlink( int df, const char *from, const struct stat *st, int dt, const char *to, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags) { _cleanup_free_ char *target = NULL; int r; assert(st); assert(to); r = readlinkat_malloc(df, from, &target); if (r < 0) return r; if (copy_flags & COPY_MAC_CREATE) { r = mac_selinux_create_file_prepare_at(dt, to, S_IFLNK); if (r < 0) return r; } r = RET_NERRNO(symlinkat(target, dt, to)); if (copy_flags & COPY_MAC_CREATE) mac_selinux_create_file_clear(); if (r < 0) { if (FLAGS_SET(copy_flags, COPY_GRACEFUL_WARN) && (ERRNO_IS_PRIVILEGE(r) || ERRNO_IS_NOT_SUPPORTED(r))) { log_notice_errno(r, "Failed to copy symlink%s%s%s, ignoring: %m", isempty(from) ? "" : " '", strempty(from), isempty(from) ? "" : "'"); return 0; } return r; } if (fchownat(dt, to, uid_is_valid(override_uid) ? override_uid : st->st_uid, gid_is_valid(override_gid) ? override_gid : st->st_gid, AT_SYMLINK_NOFOLLOW) < 0) r = -errno; (void) copy_xattr(df, from, dt, to, copy_flags); (void) utimensat(dt, to, (struct timespec[]) { st->st_atim, st->st_mtim }, AT_SYMLINK_NOFOLLOW); return r; } /* Encapsulates the database we store potential hardlink targets in */ typedef struct HardlinkContext { int dir_fd; /* An fd to the directory we use as lookup table. Never AT_FDCWD. Lazily created, when * we add the first entry. */ /* These two fields are used to create the hardlink repository directory above — via * mkdirat(parent_fd, subdir) — and are kept so that we can automatically remove the directory again * when we are done. */ int parent_fd; /* Possibly AT_FDCWD */ char *subdir; } HardlinkContext; static int hardlink_context_setup( HardlinkContext *c, int dt, const char *to, CopyFlags copy_flags) { _cleanup_close_ int dt_copy = -EBADF; int r; assert(c); assert(c->dir_fd < 0 && c->dir_fd != AT_FDCWD); assert(c->parent_fd < 0); assert(!c->subdir); /* If hardlink recreation is requested we have to maintain a database of inodes that are potential * hardlink sources. Given that generally disk sizes have to be assumed to be larger than what fits * into physical RAM we cannot maintain that database in dynamic memory alone. Here we opt to * maintain it on disk, to simplify things: inside the destination directory we'll maintain a * temporary directory consisting of hardlinks of every inode we copied that might be subject of * hardlinks. We can then use that as hardlink source later on. Yes, this means additional disk IO * but thankfully Linux is optimized for this kind of thing. If this ever becomes a performance * bottleneck we can certainly place an in-memory hash table in front of this, but for the beginning, * let's keep things simple, and just use the disk as lookup table for inodes. * * Note that this should have zero performance impact as long as .n_link of all files copied remains * <= 0, because in that case we will not actually allocate the hardlink inode lookup table directory * on disk (we do so lazily, when the first candidate with .n_link > 1 is seen). This means, in the * common case where hardlinks are not used at all or only for few files the fact that we store the * table on disk shouldn't matter perfomance-wise. */ if (!FLAGS_SET(copy_flags, COPY_HARDLINKS)) return 0; if (dt == AT_FDCWD) dt_copy = AT_FDCWD; else if (dt < 0) return -EBADF; else { dt_copy = fcntl(dt, F_DUPFD_CLOEXEC, 3); if (dt_copy < 0) return -errno; } r = tempfn_random_child(to, "hardlink", &c->subdir); if (r < 0) return r; c->parent_fd = TAKE_FD(dt_copy); /* We don't actually create the directory we keep the table in here, that's done on-demand when the * first entry is added, using hardlink_context_realize() below. */ return 1; } static int hardlink_context_realize(HardlinkContext *c) { if (!c) return 0; if (c->dir_fd >= 0) /* Already realized */ return 1; if (c->parent_fd < 0 && c->parent_fd != AT_FDCWD) /* Not configured */ return 0; assert(c->subdir); c->dir_fd = open_mkdir_at(c->parent_fd, c->subdir, O_EXCL|O_CLOEXEC, 0700); if (c->dir_fd < 0) return c->dir_fd; return 1; } static void hardlink_context_destroy(HardlinkContext *c) { int r; assert(c); /* Automatically remove the hardlink lookup table directory again after we are done. This is used via * _cleanup_() so that we really delete this, even on failure. */ if (c->dir_fd >= 0) { /* might be have already been used for reading, so we need to rewind it. */ if (lseek(c->dir_fd, 0, SEEK_SET) < 0) log_debug_errno(errno, "Failed to lseek on file descriptor, ignoring: %m"); r = rm_rf_children(TAKE_FD(c->dir_fd), REMOVE_PHYSICAL, NULL); /* consumes dir_fd in all cases, even on failure */ if (r < 0) log_debug_errno(r, "Failed to remove hardlink store (%s) contents, ignoring: %m", c->subdir); assert(c->parent_fd >= 0 || c->parent_fd == AT_FDCWD); assert(c->subdir); if (unlinkat(c->parent_fd, c->subdir, AT_REMOVEDIR) < 0) log_debug_errno(errno, "Failed to remove hardlink store (%s) directory, ignoring: %m", c->subdir); } assert_cc(AT_FDCWD < 0); c->parent_fd = safe_close(c->parent_fd); c->subdir = mfree(c->subdir); } static int try_hardlink( HardlinkContext *c, const struct stat *st, int dt, const char *to) { char dev_ino[DECIMAL_STR_MAX(dev_t)*2 + DECIMAL_STR_MAX(uint64_t) + 4]; assert(st); assert(dt >= 0 || dt == AT_FDCWD); assert(to); if (!c) /* No temporary hardlink directory, don't bother */ return 0; if (st->st_nlink <= 1) /* Source not hardlinked, don't bother */ return 0; if (c->dir_fd < 0) /* not yet realized, hence empty */ return 0; xsprintf(dev_ino, "%u:%u:%" PRIu64, major(st->st_dev), minor(st->st_dev), (uint64_t) st->st_ino); if (linkat(c->dir_fd, dev_ino, dt, to, 0) < 0) { if (errno != ENOENT) /* doesn't exist in store yet */ log_debug_errno(errno, "Failed to hardlink %s to %s, ignoring: %m", dev_ino, to); return 0; } return 1; } static int memorize_hardlink( HardlinkContext *c, const struct stat *st, int dt, const char *to) { char dev_ino[DECIMAL_STR_MAX(dev_t)*2 + DECIMAL_STR_MAX(uint64_t) + 4]; int r; assert(st); assert(dt >= 0 || dt == AT_FDCWD); assert(to); if (!c) /* No temporary hardlink directory, don't bother */ return 0; if (st->st_nlink <= 1) /* Source not hardlinked, don't bother */ return 0; r = hardlink_context_realize(c); /* Create the hardlink store lazily */ if (r < 0) return r; xsprintf(dev_ino, "%u:%u:%" PRIu64, major(st->st_dev), minor(st->st_dev), (uint64_t) st->st_ino); if (linkat(dt, to, c->dir_fd, dev_ino, 0) < 0) { log_debug_errno(errno, "Failed to hardlink %s to %s, ignoring: %m", to, dev_ino); return 0; } return 1; } static int fd_copy_tree_generic( int df, const char *from, const struct stat *st, int dt, const char *to, dev_t original_device, unsigned depth_left, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags, Hashmap *denylist, Set *subvolumes, HardlinkContext *hardlink_context, const char *display_path, copy_progress_path_t progress_path, copy_progress_bytes_t progress_bytes, void *userdata); static int fd_copy_regular( int df, const char *from, const struct stat *st, int dt, const char *to, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags, HardlinkContext *hardlink_context, copy_progress_bytes_t progress, void *userdata) { _cleanup_close_ int fdf = -EBADF, fdt = -EBADF; int r, q; assert(st); assert(to); r = try_hardlink(hardlink_context, st, dt, to); if (r < 0) return r; if (r > 0) /* worked! */ return 0; fdf = xopenat(df, from, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); if (fdf < 0) return fdf; if (copy_flags & COPY_MAC_CREATE) { r = mac_selinux_create_file_prepare_at(dt, to, S_IFREG); if (r < 0) return r; } fdt = openat(dt, to, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, st->st_mode & 07777); if (copy_flags & COPY_MAC_CREATE) mac_selinux_create_file_clear(); if (fdt < 0) return -errno; r = copy_bytes_full(fdf, fdt, UINT64_MAX, copy_flags, NULL, NULL, progress, userdata); if (r < 0) goto fail; if (fchown(fdt, uid_is_valid(override_uid) ? override_uid : st->st_uid, gid_is_valid(override_gid) ? override_gid : st->st_gid) < 0) r = -errno; if (fchmod(fdt, st->st_mode & 07777) < 0) r = -errno; (void) futimens(fdt, (struct timespec[]) { st->st_atim, st->st_mtim }); (void) copy_xattr(fdf, NULL, fdt, NULL, copy_flags); if (FLAGS_SET(copy_flags, COPY_VERIFY_LINKED)) { r = fd_verify_linked(fdf); if (r < 0) return r; } if (copy_flags & COPY_FSYNC) { if (fsync(fdt) < 0) { r = -errno; goto fail; } } q = close_nointr(TAKE_FD(fdt)); /* even if this fails, the fd is now invalidated */ if (q < 0) { r = q; goto fail; } (void) memorize_hardlink(hardlink_context, st, dt, to); return r; fail: (void) unlinkat(dt, to, 0); return r; } static int fd_copy_fifo( int df, const char *from, const struct stat *st, int dt, const char *to, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags, HardlinkContext *hardlink_context) { int r; assert(st); assert(to); r = try_hardlink(hardlink_context, st, dt, to); if (r < 0) return r; if (r > 0) /* worked! */ return 0; if (copy_flags & COPY_MAC_CREATE) { r = mac_selinux_create_file_prepare_at(dt, to, S_IFIFO); if (r < 0) return r; } r = RET_NERRNO(mkfifoat(dt, to, st->st_mode & 07777)); if (copy_flags & COPY_MAC_CREATE) mac_selinux_create_file_clear(); if (FLAGS_SET(copy_flags, COPY_GRACEFUL_WARN) && (ERRNO_IS_NEG_PRIVILEGE(r) || ERRNO_IS_NEG_NOT_SUPPORTED(r))) { log_notice_errno(r, "Failed to copy fifo%s%s%s, ignoring: %m", isempty(from) ? "" : " '", strempty(from), isempty(from) ? "" : "'"); return 0; } else if (r < 0) return r; if (fchownat(dt, to, uid_is_valid(override_uid) ? override_uid : st->st_uid, gid_is_valid(override_gid) ? override_gid : st->st_gid, AT_SYMLINK_NOFOLLOW) < 0) r = -errno; if (fchmodat(dt, to, st->st_mode & 07777, 0) < 0) r = -errno; (void) utimensat(dt, to, (struct timespec[]) { st->st_atim, st->st_mtim }, AT_SYMLINK_NOFOLLOW); (void) memorize_hardlink(hardlink_context, st, dt, to); return r; } static int fd_copy_node( int df, const char *from, const struct stat *st, int dt, const char *to, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags, HardlinkContext *hardlink_context) { int r; assert(st); assert(to); r = try_hardlink(hardlink_context, st, dt, to); if (r < 0) return r; if (r > 0) /* worked! */ return 0; if (copy_flags & COPY_MAC_CREATE) { r = mac_selinux_create_file_prepare_at(dt, to, st->st_mode & S_IFMT); if (r < 0) return r; } r = RET_NERRNO(mknodat(dt, to, st->st_mode, st->st_rdev)); if (copy_flags & COPY_MAC_CREATE) mac_selinux_create_file_clear(); if (FLAGS_SET(copy_flags, COPY_GRACEFUL_WARN) && (ERRNO_IS_NEG_PRIVILEGE(r) || ERRNO_IS_NEG_NOT_SUPPORTED(r))) { log_notice_errno(r, "Failed to copy node%s%s%s, ignoring: %m", isempty(from) ? "" : " '", strempty(from), isempty(from) ? "" : "'"); return 0; } else if (r < 0) return r; if (fchownat(dt, to, uid_is_valid(override_uid) ? override_uid : st->st_uid, gid_is_valid(override_gid) ? override_gid : st->st_gid, AT_SYMLINK_NOFOLLOW) < 0) r = -errno; if (fchmodat(dt, to, st->st_mode & 07777, 0) < 0) r = -errno; (void) utimensat(dt, to, (struct timespec[]) { st->st_atim, st->st_mtim }, AT_SYMLINK_NOFOLLOW); (void) memorize_hardlink(hardlink_context, st, dt, to); return r; } static int fd_copy_directory( int df, const char *from, const struct stat *st, int dt, const char *to, dev_t original_device, unsigned depth_left, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags, Hashmap *denylist, Set *subvolumes, HardlinkContext *hardlink_context, const char *display_path, copy_progress_path_t progress_path, copy_progress_bytes_t progress_bytes, void *userdata) { _cleanup_(hardlink_context_destroy) HardlinkContext our_hardlink_context = { .dir_fd = -EBADF, .parent_fd = -EBADF, }; _cleanup_close_ int fdf = -EBADF, fdt = -EBADF; _cleanup_closedir_ DIR *d = NULL; struct stat dt_st; bool exists; int r; assert(st); assert(to); if (depth_left == 0) return -ENAMETOOLONG; fdf = xopenat(df, from, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); if (fdf < 0) return fdf; if (!hardlink_context) { /* If recreating hardlinks is requested let's set up a context for that now. */ r = hardlink_context_setup(&our_hardlink_context, dt, to, copy_flags); if (r < 0) return r; if (r > 0) /* It's enabled and allocated, let's now use the same context for all recursive * invocations from here down */ hardlink_context = &our_hardlink_context; } d = take_fdopendir(&fdf); if (!d) return -errno; r = dir_is_empty_at(dt, to, /* ignore_hidden_or_backup= */ false); if (r < 0 && r != -ENOENT) return r; if ((r > 0 && !(copy_flags & (COPY_MERGE|COPY_MERGE_EMPTY))) || (r == 0 && !FLAGS_SET(copy_flags, COPY_MERGE))) return -EEXIST; exists = r >= 0; fdt = xopenat_lock_full(dt, to, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|(exists ? 0 : O_CREAT|O_EXCL), (copy_flags & COPY_MAC_CREATE ? XO_LABEL : 0)|(set_contains(subvolumes, st) ? XO_SUBVOLUME : 0), st->st_mode & 07777, copy_flags & COPY_LOCK_BSD ? LOCK_BSD : LOCK_NONE, LOCK_EX); if (fdt < 0) return fdt; if (exists && FLAGS_SET(copy_flags, COPY_RESTORE_DIRECTORY_TIMESTAMPS) && fstat(fdt, &dt_st) < 0) return -errno; r = 0; if (PTR_TO_INT(hashmap_get(denylist, st)) == DENY_CONTENTS) { log_debug("%s is in the denylist, not recursing", from ?: "file to copy"); goto finish; } FOREACH_DIRENT_ALL(de, d, return -errno) { const char *child_display_path = NULL; _cleanup_free_ char *dp = NULL; struct stat buf; int q; if (dot_or_dot_dot(de->d_name)) continue; r = look_for_signals(copy_flags); if (r < 0) return r; if (fstatat(dirfd(d), de->d_name, &buf, AT_SYMLINK_NOFOLLOW) < 0) { r = -errno; continue; } if (progress_path) { if (display_path) child_display_path = dp = path_join(display_path, de->d_name); else child_display_path = de->d_name; r = progress_path(child_display_path, &buf, userdata); if (r < 0) return r; } if (PTR_TO_INT(hashmap_get(denylist, &buf)) == DENY_INODE) { log_debug("%s%s%s is in the denylist, ignoring", strempty(from), isempty(from) ? "" : "/", de->d_name); continue; } if (S_ISDIR(buf.st_mode)) { /* * Don't descend into directories on other file systems, if this is requested. We do a simple * .st_dev check here, which basically comes for free. Note that we do this check only on * directories, not other kind of file system objects, for two reason: * * • The kernel's overlayfs pseudo file system that overlays multiple real file systems * propagates the .st_dev field of the file system a file originates from all the way up * through the stack to stat(). It doesn't do that for directories however. This means that * comparing .st_dev on non-directories suggests that they all are mount points. To avoid * confusion we hence avoid relying on this check for regular files. * * • The main reason we do this check at all is to protect ourselves from bind mount cycles, * where we really want to avoid descending down in all eternity. However the .st_dev check * is usually not sufficient for this protection anyway, as bind mount cycles from the same * file system onto itself can't be detected that way. (Note we also do a recursion depth * check, which is probably the better protection in this regard, which is why * COPY_SAME_MOUNT is optional). */ if (FLAGS_SET(copy_flags, COPY_SAME_MOUNT)) { if (buf.st_dev != original_device) continue; r = fd_is_mount_point(dirfd(d), de->d_name, 0); if (r < 0) return r; if (r > 0) continue; } } q = fd_copy_tree_generic(dirfd(d), de->d_name, &buf, fdt, de->d_name, original_device, depth_left-1, override_uid, override_gid, copy_flags & ~COPY_LOCK_BSD, denylist, subvolumes, hardlink_context, child_display_path, progress_path, progress_bytes, userdata); if (q == -EINTR) /* Propagate SIGINT/SIGTERM up instantly */ return q; if (q == -EEXIST && (copy_flags & COPY_MERGE)) q = 0; if (q < 0) r = q; } finish: if (!exists) { if (fchown(fdt, uid_is_valid(override_uid) ? override_uid : st->st_uid, gid_is_valid(override_gid) ? override_gid : st->st_gid) < 0) r = -errno; if (fchmod(fdt, st->st_mode & 07777) < 0) r = -errno; /* Run hardlink context cleanup now because it potentially changes timestamps */ hardlink_context_destroy(&our_hardlink_context); (void) copy_xattr(dirfd(d), NULL, fdt, NULL, copy_flags); (void) futimens(fdt, (struct timespec[]) { st->st_atim, st->st_mtim }); } else if (FLAGS_SET(copy_flags, COPY_RESTORE_DIRECTORY_TIMESTAMPS)) { /* Run hardlink context cleanup now because it potentially changes timestamps */ hardlink_context_destroy(&our_hardlink_context); /* If the directory already exists, make sure the timestamps stay the same as before. */ (void) futimens(fdt, (struct timespec[]) { dt_st.st_atim, dt_st.st_mtim }); } if (copy_flags & COPY_FSYNC_FULL) { if (fsync(fdt) < 0) return -errno; } if (r < 0) return r; return copy_flags & COPY_LOCK_BSD ? TAKE_FD(fdt) : 0; } static int fd_copy_leaf( int df, const char *from, const struct stat *st, int dt, const char *to, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags, HardlinkContext *hardlink_context, const char *display_path, copy_progress_bytes_t progress_bytes, void *userdata) { int r; if (S_ISREG(st->st_mode)) r = fd_copy_regular(df, from, st, dt, to, override_uid, override_gid, copy_flags, hardlink_context, progress_bytes, userdata); else if (S_ISLNK(st->st_mode)) r = fd_copy_symlink(df, from, st, dt, to, override_uid, override_gid, copy_flags); else if (S_ISFIFO(st->st_mode)) r = fd_copy_fifo(df, from, st, dt, to, override_uid, override_gid, copy_flags, hardlink_context); else if (S_ISBLK(st->st_mode) || S_ISCHR(st->st_mode) || S_ISSOCK(st->st_mode)) r = fd_copy_node(df, from, st, dt, to, override_uid, override_gid, copy_flags, hardlink_context); else r = -EOPNOTSUPP; return r; } static int fd_copy_tree_generic( int df, const char *from, const struct stat *st, int dt, const char *to, dev_t original_device, unsigned depth_left, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags, Hashmap *denylist, Set *subvolumes, HardlinkContext *hardlink_context, const char *display_path, copy_progress_path_t progress_path, copy_progress_bytes_t progress_bytes, void *userdata) { int r; assert(!FLAGS_SET(copy_flags, COPY_LOCK_BSD)); if (S_ISDIR(st->st_mode)) return fd_copy_directory(df, from, st, dt, to, original_device, depth_left-1, override_uid, override_gid, copy_flags, denylist, subvolumes, hardlink_context, display_path, progress_path, progress_bytes, userdata); DenyType t = PTR_TO_INT(hashmap_get(denylist, st)); if (t == DENY_INODE) { log_debug("%s is in the denylist, ignoring", from ?: "file to copy"); return 0; } else if (t == DENY_CONTENTS) log_debug("%s is configured to have its contents excluded, but is not a directory", from ?: "file to copy"); r = fd_copy_leaf(df, from, st, dt, to, override_uid, override_gid, copy_flags, hardlink_context, display_path, progress_bytes, userdata); /* We just tried to copy a leaf node of the tree. If it failed because the node already exists *and* the COPY_REPLACE flag has been provided, we should unlink the node and re-copy. */ if (r == -EEXIST && (copy_flags & COPY_REPLACE)) { /* This codepath is us trying to address an error to copy, if the unlink fails, lets just return the original error. */ if (unlinkat(dt, to, 0) < 0) return r; r = fd_copy_leaf(df, from, st, dt, to, override_uid, override_gid, copy_flags, hardlink_context, display_path, progress_bytes, userdata); } return r; } int copy_tree_at_full( int fdf, const char *from, int fdt, const char *to, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags, Hashmap *denylist, Set *subvolumes, copy_progress_path_t progress_path, copy_progress_bytes_t progress_bytes, void *userdata) { struct stat st; int r; assert(to); assert(!FLAGS_SET(copy_flags, COPY_LOCK_BSD)); if (fstatat(fdf, strempty(from), &st, AT_SYMLINK_NOFOLLOW | (isempty(from) ? AT_EMPTY_PATH : 0)) < 0) return -errno; r = fd_copy_tree_generic(fdf, from, &st, fdt, to, st.st_dev, COPY_DEPTH_MAX, override_uid, override_gid, copy_flags, denylist, subvolumes, NULL, NULL, progress_path, progress_bytes, userdata); if (r < 0) return r; if (S_ISDIR(st.st_mode) && (copy_flags & COPY_SYNCFS)) { /* If the top-level inode is a directory run syncfs() now. */ r = syncfs_path(fdt, to); if (r < 0) return r; } else if ((copy_flags & (COPY_FSYNC_FULL|COPY_SYNCFS)) != 0) { /* fsync() the parent dir of what we just copied if COPY_FSYNC_FULL is set. Also do this in * case COPY_SYNCFS is set but the top-level inode wasn't actually a directory. We do this so that * COPY_SYNCFS provides reasonable synchronization semantics on any kind of inode: when the * copy operation is done the whole inode — regardless of its type — and all its children * will be synchronized to disk. */ r = fsync_parent_at(fdt, to); if (r < 0) return r; } return 0; } static int sync_dir_by_flags(int dir_fd, const char *path, CopyFlags copy_flags) { assert(dir_fd >= 0 || dir_fd == AT_FDCWD); assert(path); if (copy_flags & COPY_SYNCFS) return syncfs_path(dir_fd, path); if (copy_flags & COPY_FSYNC_FULL) return fsync_parent_at(dir_fd, path); return 0; } int copy_directory_at_full( int dir_fdf, const char *from, int dir_fdt, const char *to, CopyFlags copy_flags, copy_progress_path_t progress_path, copy_progress_bytes_t progress_bytes, void *userdata) { _cleanup_close_ int fdt = -EBADF; struct stat st; int r; assert(dir_fdf >= 0 || dir_fdf == AT_FDCWD); assert(dir_fdt >= 0 || dir_fdt == AT_FDCWD); assert(to); if (fstatat(dir_fdf, strempty(from), &st, AT_SYMLINK_NOFOLLOW|(isempty(from) ? AT_EMPTY_PATH : 0)) < 0) return -errno; r = stat_verify_directory(&st); if (r < 0) return r; r = fd_copy_directory( dir_fdf, from, &st, dir_fdt, to, st.st_dev, COPY_DEPTH_MAX, UID_INVALID, GID_INVALID, copy_flags, NULL, NULL, NULL, NULL, progress_path, progress_bytes, userdata); if (r < 0) return r; if (FLAGS_SET(copy_flags, COPY_LOCK_BSD)) fdt = r; r = sync_dir_by_flags(dir_fdt, to, copy_flags); if (r < 0) return r; return FLAGS_SET(copy_flags, COPY_LOCK_BSD) ? TAKE_FD(fdt) : 0; } int copy_file_fd_at_full( int dir_fdf, const char *from, int fdt, CopyFlags copy_flags, copy_progress_bytes_t progress_bytes, void *userdata) { _cleanup_close_ int fdf = -EBADF; struct stat st; int r; assert(dir_fdf >= 0 || dir_fdf == AT_FDCWD); assert(fdt >= 0); assert(!FLAGS_SET(copy_flags, COPY_LOCK_BSD)); fdf = xopenat(dir_fdf, from, O_RDONLY|O_CLOEXEC|O_NOCTTY); if (fdf < 0) return fdf; r = fd_verify_regular(fdf); if (r < 0) return r; if (fstat(fdt, &st) < 0) return -errno; r = copy_bytes_full(fdf, fdt, UINT64_MAX, copy_flags, NULL, NULL, progress_bytes, userdata); if (r < 0) return r; /* Make sure to copy file attributes only over if target is a regular * file (so that copying a file to /dev/null won't alter the access * mode/ownership of that device node...) */ if (S_ISREG(st.st_mode)) { (void) copy_times(fdf, fdt, copy_flags); (void) copy_xattr(fdf, NULL, fdt, NULL, copy_flags); } if (FLAGS_SET(copy_flags, COPY_VERIFY_LINKED)) { r = fd_verify_linked(fdf); if (r < 0) return r; } if (copy_flags & COPY_FSYNC_FULL) { r = fsync_full(fdt); if (r < 0) return r; } else if (copy_flags & COPY_FSYNC) { if (fsync(fdt) < 0) return -errno; } return 0; } int copy_file_at_full( int dir_fdf, const char *from, int dir_fdt, const char *to, int flags, mode_t mode, unsigned chattr_flags, unsigned chattr_mask, CopyFlags copy_flags, copy_progress_bytes_t progress_bytes, void *userdata) { _cleanup_close_ int fdf = -EBADF, fdt = -EBADF; struct stat st; int r; assert(dir_fdf >= 0 || dir_fdf == AT_FDCWD); assert(dir_fdt >= 0 || dir_fdt == AT_FDCWD); assert(to); fdf = xopenat(dir_fdf, from, O_RDONLY|O_CLOEXEC|O_NOCTTY); if (fdf < 0) return fdf; if (fstat(fdf, &st) < 0) return -errno; r = stat_verify_regular(&st); if (r < 0) return r; WITH_UMASK(0000) { fdt = xopenat_lock_full(dir_fdt, to, flags|O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, (copy_flags & COPY_MAC_CREATE ? XO_LABEL : 0), mode != MODE_INVALID ? mode : st.st_mode, copy_flags & COPY_LOCK_BSD ? LOCK_BSD : LOCK_NONE, LOCK_EX); if (fdt < 0) return fdt; } if (!FLAGS_SET(flags, O_EXCL)) { /* if O_EXCL was used we created the thing as regular file, no need to check again */ r = fd_verify_regular(fdt); if (r < 0) goto fail; } if (chattr_mask != 0) (void) chattr_fd(fdt, chattr_flags, chattr_mask & CHATTR_EARLY_FL, NULL); r = copy_bytes_full(fdf, fdt, UINT64_MAX, copy_flags & ~COPY_LOCK_BSD, NULL, NULL, progress_bytes, userdata); if (r < 0) goto fail; (void) copy_times(fdf, fdt, copy_flags); (void) copy_xattr(fdf, NULL, fdt, NULL, copy_flags); if (FLAGS_SET(copy_flags, COPY_VERIFY_LINKED)) { r = fd_verify_linked(fdf); if (r < 0) goto fail; } if (chattr_mask != 0) (void) chattr_fd(fdt, chattr_flags, chattr_mask & ~CHATTR_EARLY_FL, NULL); if (copy_flags & (COPY_FSYNC|COPY_FSYNC_FULL)) { if (fsync(fdt) < 0) { r = -errno; goto fail; } } if (!FLAGS_SET(copy_flags, COPY_LOCK_BSD)) { r = close_nointr(TAKE_FD(fdt)); /* even if this fails, the fd is now invalidated */ if (r < 0) goto fail; } if (copy_flags & COPY_FSYNC_FULL) { r = fsync_parent_at(dir_fdt, to); if (r < 0) goto fail; } return copy_flags & COPY_LOCK_BSD ? TAKE_FD(fdt) : 0; fail: /* Only unlink if we definitely are the ones who created the file */ if (FLAGS_SET(flags, O_EXCL)) (void) unlinkat(dir_fdt, to, 0); return r; } int copy_file_atomic_at_full( int dir_fdf, const char *from, int dir_fdt, const char *to, mode_t mode, unsigned chattr_flags, unsigned chattr_mask, CopyFlags copy_flags, copy_progress_bytes_t progress_bytes, void *userdata) { _cleanup_(unlink_and_freep) char *t = NULL; _cleanup_close_ int fdt = -EBADF; int r; assert(to); assert(!FLAGS_SET(copy_flags, COPY_LOCK_BSD)); if (copy_flags & COPY_MAC_CREATE) { r = mac_selinux_create_file_prepare_at(dir_fdt, to, S_IFREG); if (r < 0) return r; } fdt = open_tmpfile_linkable_at(dir_fdt, to, O_WRONLY|O_CLOEXEC, &t); if (copy_flags & COPY_MAC_CREATE) mac_selinux_create_file_clear(); if (fdt < 0) return fdt; if (chattr_mask != 0) (void) chattr_fd(fdt, chattr_flags, chattr_mask & CHATTR_EARLY_FL, NULL); r = copy_file_fd_at_full(dir_fdf, from, fdt, copy_flags, progress_bytes, userdata); if (r < 0) return r; if (fchmod(fdt, mode) < 0) return -errno; if ((copy_flags & (COPY_FSYNC|COPY_FSYNC_FULL))) { /* Sync the file */ if (fsync(fdt) < 0) return -errno; } r = link_tmpfile_at(fdt, dir_fdt, t, to, (copy_flags & COPY_REPLACE) ? LINK_TMPFILE_REPLACE : 0); if (r < 0) return r; t = mfree(t); if (chattr_mask != 0) (void) chattr_fd(fdt, chattr_flags, chattr_mask & ~CHATTR_EARLY_FL, NULL); r = close_nointr(TAKE_FD(fdt)); /* even if this fails, the fd is now invalidated */ if (r < 0) goto fail; if (copy_flags & COPY_FSYNC_FULL) { /* Sync the parent directory */ r = fsync_parent_at(dir_fdt, to); if (r < 0) goto fail; } return 0; fail: (void) unlinkat(dir_fdt, to, 0); return r; } int copy_times(int fdf, int fdt, CopyFlags flags) { struct stat st; assert(fdf >= 0); assert(fdt >= 0); if (fstat(fdf, &st) < 0) return -errno; if (futimens(fdt, (struct timespec[2]) { st.st_atim, st.st_mtim }) < 0) return -errno; if (FLAGS_SET(flags, COPY_CRTIME)) { usec_t crtime; if (fd_getcrtime(fdf, &crtime) >= 0) (void) fd_setcrtime(fdt, crtime); } return 0; } int copy_access(int fdf, int fdt) { struct stat st; assert(fdf >= 0); assert(fdt >= 0); /* Copies just the access mode (and not the ownership) from fdf to fdt */ if (fstat(fdf, &st) < 0) return -errno; return RET_NERRNO(fchmod(fdt, st.st_mode & 07777)); } int copy_rights_with_fallback(int fdf, int fdt, const char *patht) { struct stat st; assert(fdf >= 0); assert(fdt >= 0); /* Copies both access mode and ownership from fdf to fdt */ if (fstat(fdf, &st) < 0) return -errno; return fchmod_and_chown_with_fallback(fdt, patht, st.st_mode & 07777, st.st_uid, st.st_gid); } int copy_xattr(int df, const char *from, int dt, const char *to, CopyFlags copy_flags) { _cleanup_free_ char *names = NULL; int ret = 0, r; r = listxattr_at_malloc(df, from, 0, &names); if (r < 0) return r; NULSTR_FOREACH(p, names) { _cleanup_free_ char *value = NULL; if (!FLAGS_SET(copy_flags, COPY_ALL_XATTRS) && !startswith(p, "user.")) continue; r = getxattr_at_malloc(df, from, p, 0, &value); if (r == -ENODATA) continue; /* gone by now */ if (r < 0) return r; if (xsetxattr(dt, to, p, value, r, 0) < 0) ret = -errno; } return ret; } int reflink(int infd, int outfd) { int r; assert(infd >= 0); assert(outfd >= 0); /* Make sure we invoke the ioctl on a regular file, so that no device driver accidentally gets it. */ r = fd_verify_regular(outfd); if (r < 0) return r; /* FICLONE was introduced in Linux 4.5 but it uses the same number as BTRFS_IOC_CLONE introduced earlier */ assert_cc(FICLONE == BTRFS_IOC_CLONE); return RET_NERRNO(ioctl(outfd, FICLONE, infd)); } assert_cc(sizeof(struct file_clone_range) == sizeof(struct btrfs_ioctl_clone_range_args)); int reflink_range(int infd, uint64_t in_offset, int outfd, uint64_t out_offset, uint64_t sz) { struct file_clone_range args = { .src_fd = infd, .src_offset = in_offset, .src_length = sz, .dest_offset = out_offset, }; int r; assert(infd >= 0); assert(outfd >= 0); /* Inside the kernel, FICLONE is identical to FICLONERANGE with offsets and size set to zero, let's * simplify things and use the simple ioctl in that case. Also, do the same if the size is * UINT64_MAX, which is how we usually encode "everything". */ if (in_offset == 0 && out_offset == 0 && IN_SET(sz, 0, UINT64_MAX)) return reflink(infd, outfd); r = fd_verify_regular(outfd); if (r < 0) return r; assert_cc(FICLONERANGE == BTRFS_IOC_CLONE_RANGE); return RET_NERRNO(ioctl(outfd, FICLONERANGE, &args)); }