/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2014 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <sys/sendfile.h> #include <sys/xattr.h> #include "util.h" #include "btrfs-util.h" #include "copy.h" #define COPY_BUFFER_SIZE (16*1024) int copy_bytes(int fdf, int fdt, off_t max_bytes, bool try_reflink) { bool try_sendfile = true; int r; assert(fdf >= 0); assert(fdt >= 0); /* Try btrfs reflinks first. */ if (try_reflink && max_bytes == (off_t) -1) { r = btrfs_reflink(fdf, fdt); if (r >= 0) return r; } for (;;) { size_t m = COPY_BUFFER_SIZE; ssize_t n; if (max_bytes != (off_t) -1) { if (max_bytes <= 0) return -EFBIG; if ((off_t) m > max_bytes) m = (size_t) max_bytes; } /* First try sendfile(), unless we already tried */ if (try_sendfile) { n = sendfile(fdt, fdf, NULL, m); if (n < 0) { if (errno != EINVAL && errno != ENOSYS) return -errno; try_sendfile = false; /* use fallback below */ } else if (n == 0) /* EOF */ break; else if (n > 0) /* Succcess! */ goto next; } /* As a fallback just copy bits by hand */ { char buf[m]; n = read(fdf, buf, m); if (n < 0) return -errno; if (n == 0) /* EOF */ break; r = loop_write(fdt, buf, (size_t) n, false); if (r < 0) return r; } next: if (max_bytes != (off_t) -1) { assert(max_bytes >= n); max_bytes -= n; } } return 0; } static int fd_copy_symlink(int df, const char *from, const struct stat *st, int dt, const char *to) { _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, st->st_uid, 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) { _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, (off_t) -1, true); if (r < 0) { unlinkat(dt, to, 0); return r; } if (fchown(fdt, st->st_uid, 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; 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) { 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, st->st_uid, 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) { 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, st->st_uid, 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, bool merge) { _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); 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 && 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; if (created) { struct timespec ut[2] = { st->st_atim, st->st_mtim }; if (fchown(fdt, st->st_uid, st->st_gid) < 0) r = -errno; if (fchmod(fdt, st->st_mode & 07777) < 0) r = -errno; (void) futimens(fdt, ut); (void) copy_xattr(dirfd(d), fdt); } FOREACH_DIRENT(de, d, return -errno) { struct stat buf; int q; 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); else if (S_ISDIR(buf.st_mode)) q = fd_copy_directory(dirfd(d), de->d_name, &buf, fdt, de->d_name, original_device, merge); else if (S_ISLNK(buf.st_mode)) q = fd_copy_symlink(dirfd(d), de->d_name, &buf, fdt, de->d_name); else if (S_ISFIFO(buf.st_mode)) q = fd_copy_fifo(dirfd(d), de->d_name, &buf, fdt, de->d_name); else if (S_ISBLK(buf.st_mode) || S_ISCHR(buf.st_mode)) q = fd_copy_node(dirfd(d), de->d_name, &buf, fdt, de->d_name); else q = -ENOTSUP; if (q == -EEXIST && merge) q = 0; if (q < 0) r = q; } return r; } int copy_tree_at(int fdf, const char *from, int fdt, const char *to, bool merge) { 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); else if (S_ISDIR(st.st_mode)) return fd_copy_directory(fdf, from, &st, fdt, to, st.st_dev, merge); else if (S_ISLNK(st.st_mode)) return fd_copy_symlink(fdf, from, &st, fdt, to); else if (S_ISFIFO(st.st_mode)) return fd_copy_fifo(fdf, from, &st, fdt, to); else if (S_ISBLK(st.st_mode) || S_ISCHR(st.st_mode)) return fd_copy_node(fdf, from, &st, fdt, to); else return -ENOTSUP; } int copy_tree(const char *from, const char *to, bool merge) { return copy_tree_at(AT_FDCWD, from, AT_FDCWD, to, merge); } int copy_directory_fd(int dirfd, const char *to, bool merge) { 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, merge); } int copy_file_fd(const char *from, int fdt, bool try_reflink) { _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, (off_t) -1, try_reflink); (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) { int fdt, 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; } r = copy_file_fd(from, fdt, true); if (r < 0) { close(fdt); 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, bool replace) { _cleanup_free_ char *t; int r; assert(from); assert(to); r = tempfn_random(to, &t); if (r < 0) return r; r = copy_file(from, t, O_NOFOLLOW|O_EXCL, mode); if (r < 0) return r; if (renameat2(AT_FDCWD, t, AT_FDCWD, to, replace ? 0 : RENAME_NOREPLACE) < 0) { unlink_noerrno(t); return -errno; } return 0; } int copy_times(int fdf, int fdt) { struct timespec ut[2]; struct stat st; usec_t crtime; 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; free(bufa); bufa = NULL; } 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; free(bufb); bufb = NULL; continue; } return -errno; } if (fsetxattr(fdt, p, bufb, m, 0) < 0) ret = -errno; } p += l + 1; n -= l + 1; } return ret; }