/* SPDX-License-Identifier: LGPL-2.1+ */ /*** This file is part of systemd. Copyright 2014 Lennart Poettering ***/ //#include //#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.h" //#include "string-util.h" #include "strv.h" #include "time-util.h" //#include "umask-util.h" #include "user-util.h" //#include "xattr-util.h" #define COPY_BUFFER_SIZE (16*1024u) 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 int 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 & O_NONBLOCK) == O_NONBLOCK ? FD_IS_NONBLOCKING_PIPE : FD_IS_BLOCKING_PIPE; } int copy_bytes_full( int fdf, int fdt, uint64_t max_bytes, CopyFlags copy_flags, void **ret_remains, size_t *ret_remains_size) { bool try_cfr = true, try_sendfile = true, try_splice = true; 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); /* 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; #if 0 /// UNNEEDED by elogind /* 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 = btrfs_reflink(fdf, fdt); /* full file reflink */ else r = btrfs_clone_range(fdf, foffset, fdt, toffset, max_bytes == UINT64_MAX ? 0 : max_bytes); /* partial reflink */ if (r >= 0) { off_t t; /* 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; return 0; /* we copied the whole thing, hence hit EOF, return 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; return 1; /* we copied only some number of bytes, which worked, but this means we didn't hit EOF, return 1 */ } } log_debug_errno(r, "Reflinking didn't work, falling back to non-reflink copying: %m"); } } } #endif // 0 for (;;) { ssize_t n; if (max_bytes <= 0) return 1; /* return > 0 if we hit the max_bytes limit */ if (max_bytes != UINT64_MAX && m > max_bytes) m = max_bytes; /* 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)) return n; try_cfr = false; /* use fallback below */ } else if (n == 0) /* EOF */ break; 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) /* EOF */ break; 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) /* EOF */ break; 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 (max_bytes != (uint64_t) -1) { 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); } return 0; /* return 0 if we hit EOF earlier than the size limit */ } #if 0 /// UNNEEDED by elogind 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(from); assert(st); assert(to); r = readlinkat_malloc(df, from, &target); if (r < 0) return r; if (symlinkat(target, dt, to) < 0) return -errno; 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) return -errno; return 0; } 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) { _cleanup_close_ int fdf = -1, fdt = -1; struct timespec ts[2]; int r, q; assert(from); assert(st); assert(to); fdf = openat(df, from, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); if (fdf < 0) return -errno; fdt = openat(dt, to, O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW, st->st_mode & 07777); if (fdt < 0) return -errno; r = copy_bytes(fdf, fdt, (uint64_t) -1, copy_flags); if (r < 0) { (void) unlinkat(dt, to, 0); return r; } 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; ts[0] = st->st_atim; ts[1] = st->st_mtim; (void) futimens(fdt, ts); (void) copy_xattr(fdf, fdt); q = close(fdt); fdt = -1; if (q < 0) { r = -errno; (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) { int r; assert(from); assert(st); assert(to); r = mkfifoat(dt, to, st->st_mode & 07777); if (r < 0) return -errno; 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; 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) { int r; assert(from); assert(st); assert(to); r = mknodat(dt, to, st->st_mode, st->st_rdev); if (r < 0) return -errno; 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; 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, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags) { _cleanup_close_ int fdf = -1, fdt = -1; _cleanup_closedir_ DIR *d = NULL; struct dirent *de; bool created; int r; assert(st); assert(to); if (from) fdf = openat(df, from, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); else fdf = fcntl(df, F_DUPFD_CLOEXEC, 3); if (fdf < 0) return -errno; d = fdopendir(fdf); if (!d) return -errno; fdf = -1; r = mkdirat(dt, to, st->st_mode & 07777); if (r >= 0) created = true; else if (errno == EEXIST && (copy_flags & COPY_MERGE)) created = false; else return -errno; fdt = openat(dt, to, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW); if (fdt < 0) return -errno; r = 0; FOREACH_DIRENT_ALL(de, d, return -errno) { struct stat buf; int q; if (dot_or_dot_dot(de->d_name)) continue; if (fstatat(dirfd(d), de->d_name, &buf, AT_SYMLINK_NOFOLLOW) < 0) { r = -errno; continue; } if (buf.st_dev != original_device) continue; if (S_ISREG(buf.st_mode)) q = fd_copy_regular(dirfd(d), de->d_name, &buf, fdt, de->d_name, override_uid, override_gid, copy_flags); else if (S_ISDIR(buf.st_mode)) q = fd_copy_directory(dirfd(d), de->d_name, &buf, fdt, de->d_name, original_device, override_uid, override_gid, copy_flags); else if (S_ISLNK(buf.st_mode)) q = fd_copy_symlink(dirfd(d), de->d_name, &buf, fdt, de->d_name, override_uid, override_gid, copy_flags); else if (S_ISFIFO(buf.st_mode)) q = fd_copy_fifo(dirfd(d), de->d_name, &buf, fdt, de->d_name, override_uid, override_gid, copy_flags); else if (S_ISBLK(buf.st_mode) || S_ISCHR(buf.st_mode) || S_ISSOCK(buf.st_mode)) q = fd_copy_node(dirfd(d), de->d_name, &buf, fdt, de->d_name, override_uid, override_gid, copy_flags); else q = -EOPNOTSUPP; if (q == -EEXIST && (copy_flags & COPY_MERGE)) q = 0; if (q < 0) r = q; } if (created) { struct timespec ut[2] = { st->st_atim, st->st_mtim }; 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) copy_xattr(dirfd(d), fdt); (void) futimens(fdt, ut); } return r; } int copy_tree_at(int fdf, const char *from, int fdt, const char *to, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags) { struct stat st; assert(from); assert(to); if (fstatat(fdf, from, &st, AT_SYMLINK_NOFOLLOW) < 0) return -errno; if (S_ISREG(st.st_mode)) return fd_copy_regular(fdf, from, &st, fdt, to, override_uid, override_gid, copy_flags); else if (S_ISDIR(st.st_mode)) return fd_copy_directory(fdf, from, &st, fdt, to, st.st_dev, override_uid, override_gid, copy_flags); else if (S_ISLNK(st.st_mode)) return fd_copy_symlink(fdf, from, &st, fdt, to, override_uid, override_gid, copy_flags); else if (S_ISFIFO(st.st_mode)) return fd_copy_fifo(fdf, from, &st, fdt, to, override_uid, override_gid, copy_flags); else if (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode) || S_ISSOCK(st.st_mode)) return fd_copy_node(fdf, from, &st, fdt, to, override_uid, override_gid, copy_flags); else return -EOPNOTSUPP; } int copy_tree(const char *from, const char *to, uid_t override_uid, gid_t override_gid, CopyFlags copy_flags) { return copy_tree_at(AT_FDCWD, from, AT_FDCWD, to, override_uid, override_gid, copy_flags); } int copy_directory_fd(int dirfd, const char *to, CopyFlags copy_flags) { struct stat st; assert(dirfd >= 0); assert(to); if (fstat(dirfd, &st) < 0) return -errno; if (!S_ISDIR(st.st_mode)) return -ENOTDIR; return fd_copy_directory(dirfd, NULL, &st, AT_FDCWD, to, st.st_dev, UID_INVALID, GID_INVALID, copy_flags); } int copy_directory(const char *from, const char *to, CopyFlags copy_flags) { struct stat st; assert(from); assert(to); if (lstat(from, &st) < 0) return -errno; if (!S_ISDIR(st.st_mode)) return -ENOTDIR; return fd_copy_directory(AT_FDCWD, from, &st, AT_FDCWD, to, st.st_dev, UID_INVALID, GID_INVALID, copy_flags); } int copy_file_fd(const char *from, int fdt, CopyFlags copy_flags) { _cleanup_close_ int fdf = -1; int r; assert(from); assert(fdt >= 0); fdf = open(from, O_RDONLY|O_CLOEXEC|O_NOCTTY); if (fdf < 0) return -errno; r = copy_bytes(fdf, fdt, (uint64_t) -1, copy_flags); (void) copy_times(fdf, fdt); (void) copy_xattr(fdf, fdt); return r; } int copy_file(const char *from, const char *to, int flags, mode_t mode, unsigned chattr_flags, CopyFlags copy_flags) { int fdt = -1, r; assert(from); assert(to); RUN_WITH_UMASK(0000) { fdt = open(to, flags|O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, mode); if (fdt < 0) return -errno; } if (chattr_flags != 0) (void) chattr_fd(fdt, chattr_flags, (unsigned) -1); r = copy_file_fd(from, fdt, copy_flags); if (r < 0) { close(fdt); (void) unlink(to); return r; } if (close(fdt) < 0) { unlink_noerrno(to); return -errno; } return 0; } int copy_file_atomic(const char *from, const char *to, mode_t mode, unsigned chattr_flags, CopyFlags copy_flags) { _cleanup_free_ char *t = NULL; int r; assert(from); assert(to); r = tempfn_random(to, NULL, &t); if (r < 0) return r; r = copy_file(from, t, O_NOFOLLOW|O_EXCL, mode, chattr_flags, copy_flags); if (r < 0) return r; if (copy_flags & COPY_REPLACE) { r = renameat(AT_FDCWD, t, AT_FDCWD, to); if (r < 0) r = -errno; } else r = rename_noreplace(AT_FDCWD, t, AT_FDCWD, to); if (r < 0) { (void) unlink(t); return r; } return 0; } int copy_times(int fdf, int fdt) { struct timespec ut[2]; struct stat st; usec_t crtime = 0; assert(fdf >= 0); assert(fdt >= 0); if (fstat(fdf, &st) < 0) return -errno; ut[0] = st.st_atim; ut[1] = st.st_mtim; if (futimens(fdt, ut) < 0) return -errno; if (fd_getcrtime(fdf, &crtime) >= 0) (void) fd_setcrtime(fdt, crtime); return 0; } int copy_xattr(int fdf, int fdt) { _cleanup_free_ char *bufa = NULL, *bufb = NULL; size_t sza = 100, szb = 100; ssize_t n; int ret = 0; const char *p; for (;;) { bufa = malloc(sza); if (!bufa) return -ENOMEM; n = flistxattr(fdf, bufa, sza); if (n == 0) return 0; if (n > 0) break; if (errno != ERANGE) return -errno; sza *= 2; bufa = mfree(bufa); } p = bufa; while (n > 0) { size_t l; l = strlen(p); assert(l < (size_t) n); if (startswith(p, "user.")) { ssize_t m; if (!bufb) { bufb = malloc(szb); if (!bufb) return -ENOMEM; } m = fgetxattr(fdf, p, bufb, szb); if (m < 0) { if (errno == ERANGE) { szb *= 2; bufb = mfree(bufb); continue; } return -errno; } if (fsetxattr(fdt, p, bufb, m, 0) < 0) ret = -errno; } p += l + 1; n -= l + 1; } return ret; } #endif // 0