/* vi: set sw=4 ts=4: */ /* * Mini copy_file implementation for busybox * * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu> * SELinux support by Yuichi Nakamura <ynakam@hitachisoft.jp> * * Licensed under GPLv2 or later, see file LICENSE in this source tree. */ #include "libbb.h" // FEATURE_NON_POSIX_CP: // // POSIX: if exists and -i, ask (w/o -i assume yes). // Then open w/o EXCL (yes, not unlink!). // If open still fails and -f, try unlink, then try open again. // Result: a mess: // If dest is a (sym)link, we overwrite link destination! // (or fail, if it points to dir/nonexistent location/etc). // This is strange, but POSIX-correct. // coreutils cp has --remove-destination to override this... /* Called if open of destination, link creation etc fails. * errno must be set to relevant value ("why we cannot create dest?") * to give reasonable error message */ static int ask_and_unlink(const char *dest, int flags) { int e = errno; #if !ENABLE_FEATURE_NON_POSIX_CP if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) { /* Either it exists, or the *path* doesnt exist */ bb_perror_msg("can't create '%s'", dest); return -1; } #endif // else: act as if -f is always in effect. // We don't want "can't create" msg, we want unlink to be done // (silently unless -i). Why? POSIX cp usually succeeds with // O_TRUNC open of existing file, and user is left ignorantly happy. // With above block unconditionally enabled, non-POSIX cp // will complain a lot more than POSIX one. /* TODO: maybe we should do it only if ctty is present? */ if (flags & FILEUTILS_INTERACTIVE) { // We would not do POSIX insanity. -i asks, // then _unlinks_ the offender. Presto. // (No "opening without O_EXCL", no "unlink only if -f") // Or else we will end up having 3 open()s! fprintf(stderr, "%s: overwrite '%s'? ", applet_name, dest); if (!bb_ask_y_confirmation()) return 0; /* not allowed to overwrite */ } if (unlink(dest) < 0) { #if ENABLE_FEATURE_VERBOSE_CP_MESSAGE if (e == errno && e == ENOENT) { /* e == ENOTDIR is similar: path has non-dir component, * but in this case we don't even reach copy_file() */ bb_error_msg("can't create '%s': Path does not exist", dest); return -1; /* error */ } #endif errno = e; /* do not use errno from unlink */ bb_perror_msg("can't create '%s'", dest); return -1; /* error */ } #if ENABLE_FEATURE_CP_LONG_OPTIONS if (flags & FILEUTILS_RMDEST) if (flags & FILEUTILS_VERBOSE) printf("removed '%s'\n", dest); #endif return 1; /* ok (to try again) */ } /* Return: * -1 error, copy not made * 0 copy is made or user answered "no" in interactive mode * (failures to preserve mode/owner/times are not reported in exit code) */ int FAST_FUNC copy_file(const char *source, const char *dest, int flags) { /* This is a recursive function, try to minimize stack usage */ /* NB: each struct stat is ~100 bytes */ struct stat source_stat; struct stat dest_stat; smallint retval = 0; smallint dest_exists = 0; smallint ovr; /* Inverse of cp -d ("cp without -d") */ #define FLAGS_DEREF (flags & (FILEUTILS_DEREFERENCE + FILEUTILS_DEREFERENCE_L0)) if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) { /* This may be a dangling symlink. * Making [sym]links to dangling symlinks works, so... */ if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) goto make_links; bb_perror_msg("can't stat '%s'", source); return -1; } if (lstat(dest, &dest_stat) < 0) { if (errno != ENOENT) { bb_perror_msg("can't stat '%s'", dest); return -1; } } else { if (source_stat.st_dev == dest_stat.st_dev && source_stat.st_ino == dest_stat.st_ino ) { bb_error_msg("'%s' and '%s' are the same file", source, dest); return -1; } dest_exists = 1; } #if ENABLE_SELINUX if ((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT) && is_selinux_enabled() > 0) { security_context_t con; if (lgetfilecon(source, &con) >= 0) { if (setfscreatecon(con) < 0) { bb_perror_msg("can't set setfscreatecon %s", con); freecon(con); return -1; } } else if (errno == ENOTSUP || errno == ENODATA) { setfscreatecon_or_die(NULL); } else { bb_perror_msg("can't lgetfilecon %s", source); return -1; } } #endif if (S_ISDIR(source_stat.st_mode)) { DIR *dp; const char *tp; struct dirent *d; mode_t saved_umask = 0; if (!(flags & FILEUTILS_RECUR)) { bb_error_msg("omitting directory '%s'", source); return -1; } /* Did we ever create source ourself before? */ tp = is_in_ino_dev_hashtable(&source_stat); if (tp) { /* We did! it's a recursion! man the lifeboats... */ bb_error_msg("recursion detected, omitting directory '%s'", source); return -1; } if (dest_exists) { if (!S_ISDIR(dest_stat.st_mode)) { bb_error_msg("target '%s' is not a directory", dest); return -1; } /* race here: user can substitute a symlink between * this check and actual creation of files inside dest */ } else { /* Create DEST */ mode_t mode; saved_umask = umask(0); mode = source_stat.st_mode; if (!(flags & FILEUTILS_PRESERVE_STATUS)) mode = source_stat.st_mode & ~saved_umask; /* Allow owner to access new dir (at least for now) */ mode |= S_IRWXU; if (mkdir(dest, mode) < 0) { umask(saved_umask); bb_perror_msg("can't create directory '%s'", dest); return -1; } umask(saved_umask); /* need stat info for add_to_ino_dev_hashtable */ if (lstat(dest, &dest_stat) < 0) { bb_perror_msg("can't stat '%s'", dest); return -1; } } /* remember (dev,inode) of each created dir. * NULL: name is not remembered */ add_to_ino_dev_hashtable(&dest_stat, NULL); /* Recursively copy files in SOURCE */ dp = opendir(source); if (dp == NULL) { retval = -1; goto preserve_mode_ugid_time; } while ((d = readdir(dp)) != NULL) { char *new_source, *new_dest; new_source = concat_subpath_file(source, d->d_name); if (new_source == NULL) continue; new_dest = concat_path_file(dest, d->d_name); if (copy_file(new_source, new_dest, flags & ~FILEUTILS_DEREFERENCE_L0) < 0) retval = -1; free(new_source); free(new_dest); } closedir(dp); if (!dest_exists && chmod(dest, source_stat.st_mode & ~saved_umask) < 0 ) { bb_perror_msg("can't preserve %s of '%s'", "permissions", dest); /* retval = -1; - WRONG! copy *WAS* made */ } goto preserve_mode_ugid_time; } if (dest_exists) { if (flags & FILEUTILS_UPDATE) { if (source_stat.st_mtime <= dest_stat.st_mtime) { return 0; /* source file must be newer */ } } #if ENABLE_FEATURE_CP_LONG_OPTIONS if (flags & FILEUTILS_RMDEST) { ovr = ask_and_unlink(dest, flags); if (ovr <= 0) return ovr; dest_exists = 0; } #endif } if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) { int (*lf)(const char *oldpath, const char *newpath); make_links: /* Hmm... maybe * if (DEREF && MAKE_SOFTLINK) source = realpath(source) ? * (but realpath returns NULL on dangling symlinks...) */ lf = (flags & FILEUTILS_MAKE_SOFTLINK) ? symlink : link; if (lf(source, dest) < 0) { ovr = ask_and_unlink(dest, flags); if (ovr <= 0) return ovr; if (lf(source, dest) < 0) { bb_perror_msg("can't create link '%s'", dest); return -1; } } /* _Not_ jumping to preserve_mode_ugid_time: * (sym)links don't have those */ return 0; } if (/* "cp thing1 thing2" without -R: just open and read() from thing1 */ !(flags & FILEUTILS_RECUR) /* "cp [-opts] regular_file thing2" */ || S_ISREG(source_stat.st_mode) /* DEREF uses stat, which never returns S_ISLNK() == true. * So the below is never true: */ /* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */ ) { int src_fd; int dst_fd; mode_t new_mode; if (!FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) { /* "cp -d symlink dst": create a link */ goto dont_cat; } if (ENABLE_FEATURE_PRESERVE_HARDLINKS && !FLAGS_DEREF) { const char *link_target; link_target = is_in_ino_dev_hashtable(&source_stat); if (link_target) { if (link(link_target, dest) < 0) { ovr = ask_and_unlink(dest, flags); if (ovr <= 0) return ovr; if (link(link_target, dest) < 0) { bb_perror_msg("can't create link '%s'", dest); return -1; } } return 0; } add_to_ino_dev_hashtable(&source_stat, dest); } src_fd = open_or_warn(source, O_RDONLY); if (src_fd < 0) return -1; /* Do not try to open with weird mode fields */ new_mode = source_stat.st_mode; if (!S_ISREG(source_stat.st_mode)) new_mode = 0666; if (ENABLE_FEATURE_NON_POSIX_CP || (flags & FILEUTILS_INTERACTIVE)) { /* * O_CREAT|O_EXCL: require that file did not exist before creation */ dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode); } else { /* POSIX, and not "cp -i" */ /* * O_CREAT|O_TRUNC: create, or truncate (security problem versus (sym)link attacks) */ dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, new_mode); } if (dst_fd == -1) { ovr = ask_and_unlink(dest, flags); if (ovr <= 0) { close(src_fd); return ovr; } /* It shouldn't exist. If it exists, do not open (symlink attack?) */ dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode); if (dst_fd < 0) { close(src_fd); return -1; } } #if ENABLE_SELINUX if ((flags & (FILEUTILS_PRESERVE_SECURITY_CONTEXT|FILEUTILS_SET_SECURITY_CONTEXT)) && is_selinux_enabled() > 0 ) { security_context_t con; if (getfscreatecon(&con) == -1) { bb_perror_msg("getfscreatecon"); return -1; } if (con) { if (setfilecon(dest, con) == -1) { bb_perror_msg("setfilecon:%s,%s", dest, con); freecon(con); return -1; } freecon(con); } } #endif #if ENABLE_FEATURE_CP_REFLINK # undef BTRFS_IOCTL_MAGIC # define BTRFS_IOCTL_MAGIC 0x94 # undef BTRFS_IOC_CLONE # define BTRFS_IOC_CLONE _IOW (BTRFS_IOCTL_MAGIC, 9, int) if (flags & FILEUTILS_REFLINK) { retval = ioctl(dst_fd, BTRFS_IOC_CLONE, src_fd); if (retval == 0) goto do_close; /* reflink did not work */ if (flags & FILEUTILS_REFLINK_ALWAYS) { bb_perror_msg("failed to clone '%s' from '%s'", dest, source); goto do_close; } /* fall through to standard copy */ retval = 0; } #endif if (bb_copyfd_eof(src_fd, dst_fd) == -1) retval = -1; IF_FEATURE_CP_REFLINK(do_close:) /* Careful with writing... */ if (close(dst_fd) < 0) { bb_perror_msg("error writing to '%s'", dest); retval = -1; } /* ...but read size is already checked by bb_copyfd_eof */ close(src_fd); /* "cp /dev/something new_file" should not * copy mode of /dev/something */ if (!S_ISREG(source_stat.st_mode)) return retval; goto preserve_mode_ugid_time; } dont_cat: /* Source is a symlink or a special file */ /* We are lazy here, a bit lax with races... */ if (dest_exists) { errno = EEXIST; ovr = ask_and_unlink(dest, flags); if (ovr <= 0) return ovr; } if (S_ISLNK(source_stat.st_mode)) { char *lpath = xmalloc_readlink_or_warn(source); if (lpath) { int r = symlink(lpath, dest); if (r < 0) { /* shared message */ bb_perror_msg("can't create %slink '%s' to '%s'", "sym", dest, lpath ); free(lpath); return -1; } free(lpath); if (flags & FILEUTILS_PRESERVE_STATUS) if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0) bb_perror_msg("can't preserve %s of '%s'", "ownership", dest); } /* _Not_ jumping to preserve_mode_ugid_time: * symlinks don't have those */ goto verb_and_exit; } if (S_ISBLK(source_stat.st_mode) || S_ISCHR(source_stat.st_mode) || S_ISSOCK(source_stat.st_mode) || S_ISFIFO(source_stat.st_mode) ) { if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) { bb_perror_msg("can't create '%s'", dest); return -1; } } else { bb_error_msg("unrecognized file '%s' with mode %x", source, source_stat.st_mode); return -1; } preserve_mode_ugid_time: if (flags & FILEUTILS_PRESERVE_STATUS /* Cannot happen: */ /* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */ ) { struct timeval times[2]; times[1].tv_sec = times[0].tv_sec = source_stat.st_mtime; times[1].tv_usec = times[0].tv_usec = 0; /* BTW, utimes sets usec-precision time - just FYI */ if (utimes(dest, times) < 0) bb_perror_msg("can't preserve %s of '%s'", "times", dest); if (chown(dest, source_stat.st_uid, source_stat.st_gid) < 0) { source_stat.st_mode &= ~(S_ISUID | S_ISGID); bb_perror_msg("can't preserve %s of '%s'", "ownership", dest); } if (chmod(dest, source_stat.st_mode) < 0) bb_perror_msg("can't preserve %s of '%s'", "permissions", dest); } verb_and_exit: if (flags & FILEUTILS_VERBOSE) { printf("'%s' -> '%s'\n", source, dest); } return retval; }