libbb/copy_file.c - busybox - Git at Google

 /* vi: set sw=4 ts=4: */
 /*
  * Mini copy_file implementation for busybox
  *
  * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
  *
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  *
  */

 #include "libbb.h"

 static int retry_overwrite(const char *dest, int flags)
 {
 	if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) {
 		fprintf(stderr, "'%s' exists\n", dest);
 		return -1;
 	}
 	if (flags & FILEUTILS_INTERACTIVE) {
 		fprintf(stderr, "%s: overwrite '%s'? ", applet_name, dest);
 		if (!bb_ask_confirmation())
 			return 0; // not allowed to overwrite
 	}
 	if (unlink(dest) < 0) {
 		bb_perror_msg("cannot remove '%s'", dest);
 		return -1; // error
 	}
 	return 1; // ok (to try again)
 }

 int copy_file(const char *source, const char *dest, int flags)
 {
 	struct stat source_stat;
 	struct stat dest_stat;
 	int status = 0;
 	signed char dest_exists = 0;
 	signed char ovr;

 #define FLAGS_DEREF (flags & FILEUTILS_DEREFERENCE)

 	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("cannot stat '%s'", source);
 		return -1;
 	}

 	if (lstat(dest, &dest_stat) < 0) {
 		if (errno != ENOENT) {
 			bb_perror_msg("cannot 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 (S_ISDIR(source_stat.st_mode)) {
 		DIR *dp;
 		struct dirent *d;
 		mode_t saved_umask = 0;

 		if (!(flags & FILEUTILS_RECUR)) {
 			bb_error_msg("omitting directory '%s'", source);
 			return -1;
 		}

 		/* Create DEST.  */
 		if (dest_exists) {
 			if (!S_ISDIR(dest_stat.st_mode)) {
 				bb_error_msg("target '%s' is not a directory", dest);
 				return -1;
 			}
 		} else {
 			mode_t mode;
 			saved_umask = umask(0);

 			mode = source_stat.st_mode;
 			if (!(flags & FILEUTILS_PRESERVE_STATUS))
 				mode = source_stat.st_mode & ~saved_umask;
 			mode |= S_IRWXU;

 			if (mkdir(dest, mode) < 0) {
 				umask(saved_umask);
 				bb_perror_msg("cannot create directory '%s'", dest);
 				return -1;
 			}

 			umask(saved_umask);
 		}

 		/* Recursively copy files in SOURCE.  */
 		dp = opendir(source);
 		if (dp == NULL) {
 			status = -1;
 			goto preserve_status;
 		}

 		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) < 0)
 				status = -1;
 			free(new_source);
 			free(new_dest);
 		}
 		closedir(dp);

 		if (!dest_exists
 		 && chmod(dest, source_stat.st_mode & ~saved_umask) < 0
 		) {
 			bb_perror_msg("cannot change permissions of '%s'", dest);
 			status = -1;
 		}

 	} else 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 = retry_overwrite(dest, flags);
 			if (ovr <= 0)
 				return ovr;
 			if (lf(source, dest) < 0) {
 				bb_perror_msg("cannot create link '%s'", dest);
 				return -1;
 			}
 		}
 		return 0;

 	} else if (S_ISREG(source_stat.st_mode)
 	// Huh? DEREF uses stat, which never returns links IIRC...
 	 || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode))
 	) {
 		int src_fd;
 		int dst_fd;
 		if (ENABLE_FEATURE_PRESERVE_HARDLINKS) {
 			char *link_name;

 			if (!FLAGS_DEREF
 			 && is_in_ino_dev_hashtable(&source_stat, &link_name)
 			) {
 				if (link(link_name, dest) < 0) {
 					ovr = retry_overwrite(dest, flags);
 					if (ovr <= 0)
 						return ovr;
 					if (link(link_name, dest) < 0) {
 						bb_perror_msg("cannot create link '%s'", dest);
 						return -1;
 					}
 				}
 				return 0;
 			}
 			// TODO: probably is_in_.. and add_to_...
 			// can be combined: find_or_add_...
 			add_to_ino_dev_hashtable(&source_stat, dest);
 		}

 		src_fd = open(source, O_RDONLY);
 		if (src_fd == -1) {
 			bb_perror_msg("cannot open '%s'", source);
 			return -1;
 		}

 		// POSIX: if exists and -i, ask (w/o -i assume yes).
 		// Then open w/o EXCL.
 		// If open still fails and -f, try unlink, then try open again.
 		// Result: a mess:
 		// If dest is a softlink, we overwrite softlink's 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...
 		dst_fd = open(dest, (flags & FILEUTILS_INTERACTIVE)
 				? O_WRONLY|O_CREAT|O_TRUNC|O_EXCL
 				: O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode);
 		if (dst_fd == -1) {
 			// We would not do POSIX insanity. -i asks,
 			// then _unlinks_ the offender. Presto.
 			// Or else we will end up having 3 open()s!
 			ovr = retry_overwrite(dest, flags);
 			if (ovr <= 0) {
 				close(src_fd);
 				return ovr;
 			}
 			dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode);
 			if (dst_fd == -1) {
 				bb_perror_msg("cannot open '%s'", dest);
 				close(src_fd);
 				return -1;
 			}
 		}

 		if (bb_copyfd_eof(src_fd, dst_fd) == -1)
 			status = -1;
 		if (close(dst_fd) < 0) {
 			bb_perror_msg("cannot close '%s'", dest);
 			status = -1;
 		}
 		if (close(src_fd) < 0) {
 			bb_perror_msg("cannot close '%s'", source);
 			status = -1;
 		}

 	} else 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)
 	 || S_ISLNK(source_stat.st_mode)
 	) {
 		// We are lazy here, a bit lax with races...
 		if (dest_exists) {
 			ovr = retry_overwrite(dest, flags);
 			if (ovr <= 0)
 				return ovr;
 		}
 		if (S_ISFIFO(source_stat.st_mode)) {
 			if (mkfifo(dest, source_stat.st_mode) < 0) {
 				bb_perror_msg("cannot create fifo '%s'", dest);
 				return -1;
 			}
 		} else if (S_ISLNK(source_stat.st_mode)) {
 			char *lpath;

 			lpath = xreadlink(source);
 			if (symlink(lpath, dest) < 0) {
 				bb_perror_msg("cannot create symlink '%s'", dest);
 				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("cannot preserve %s of '%s'", "ownership", dest);

 			return 0;

 		} else {
 			if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) {
 				bb_perror_msg("cannot create '%s'", dest);
 				return -1;
 			}
 		}
 	} else {
 		bb_error_msg("internal error: unrecognized file type");
 		return -1;
 	}

  preserve_status:

 	if (flags & FILEUTILS_PRESERVE_STATUS
 	/* Cannot happen: */
 	/* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */
 	) {
 		struct utimbuf times;

 		times.actime = source_stat.st_atime;
 		times.modtime = source_stat.st_mtime;
 		if (utime(dest, &times) < 0)
 			bb_perror_msg("cannot 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("cannot preserve %s of '%s'", "ownership", dest);
 		}
 		if (chmod(dest, source_stat.st_mode) < 0)
 			bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest);
 	}

 	return status;
 }
	/* vi: set sw=4 ts=4: */
	/*
	* Mini copy_file implementation for busybox
	*
	* Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
	*
	* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
	*
	*/

	#include "libbb.h"

	static int retry_overwrite(const char *dest, int flags)
	{
	if (!(flags & (FILEUTILS_FORCE\|FILEUTILS_INTERACTIVE))) {
	fprintf(stderr, "'%s' exists\n", dest);
	return -1;
	}
	if (flags & FILEUTILS_INTERACTIVE) {
	fprintf(stderr, "%s: overwrite '%s'? ", applet_name, dest);
	if (!bb_ask_confirmation())
	return 0; // not allowed to overwrite
	}
	if (unlink(dest) < 0) {
	bb_perror_msg("cannot remove '%s'", dest);
	return -1; // error
	}
	return 1; // ok (to try again)
	}

	int copy_file(const char source, const char dest, int flags)
	{
	struct stat source_stat;
	struct stat dest_stat;
	int status = 0;
	signed char dest_exists = 0;
	signed char ovr;

	#define FLAGS_DEREF (flags & FILEUTILS_DEREFERENCE)

	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("cannot stat '%s'", source);
	return -1;
	}

	if (lstat(dest, &dest_stat) < 0) {
	if (errno != ENOENT) {
	bb_perror_msg("cannot 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 (S_ISDIR(source_stat.st_mode)) {
	DIR *dp;
	struct dirent *d;
	mode_t saved_umask = 0;

	if (!(flags & FILEUTILS_RECUR)) {
	bb_error_msg("omitting directory '%s'", source);
	return -1;
	}

	/* Create DEST. */
	if (dest_exists) {
	if (!S_ISDIR(dest_stat.st_mode)) {
	bb_error_msg("target '%s' is not a directory", dest);
	return -1;
	}
	} else {
	mode_t mode;
	saved_umask = umask(0);

	mode = source_stat.st_mode;
	if (!(flags & FILEUTILS_PRESERVE_STATUS))
	mode = source_stat.st_mode & ~saved_umask;
	mode \|= S_IRWXU;

	if (mkdir(dest, mode) < 0) {
	umask(saved_umask);
	bb_perror_msg("cannot create directory '%s'", dest);
	return -1;
	}

	umask(saved_umask);
	}

	/* Recursively copy files in SOURCE. */
	dp = opendir(source);
	if (dp == NULL) {
	status = -1;
	goto preserve_status;
	}

	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) < 0)
	status = -1;
	free(new_source);
	free(new_dest);
	}
	closedir(dp);

	if (!dest_exists
	&& chmod(dest, source_stat.st_mode & ~saved_umask) < 0
	) {
	bb_perror_msg("cannot change permissions of '%s'", dest);
	status = -1;
	}

	} else 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 = retry_overwrite(dest, flags);
	if (ovr <= 0)
	return ovr;
	if (lf(source, dest) < 0) {
	bb_perror_msg("cannot create link '%s'", dest);
	return -1;
	}
	}
	return 0;

	} else if (S_ISREG(source_stat.st_mode)
	// Huh? DEREF uses stat, which never returns links IIRC...
	\|\| (FLAGS_DEREF && S_ISLNK(source_stat.st_mode))
	) {
	int src_fd;
	int dst_fd;
	if (ENABLE_FEATURE_PRESERVE_HARDLINKS) {
	char *link_name;

	if (!FLAGS_DEREF
	&& is_in_ino_dev_hashtable(&source_stat, &link_name)
	) {
	if (link(link_name, dest) < 0) {
	ovr = retry_overwrite(dest, flags);
	if (ovr <= 0)
	return ovr;
	if (link(link_name, dest) < 0) {
	bb_perror_msg("cannot create link '%s'", dest);
	return -1;
	}
	}
	return 0;
	}
	// TODO: probably is_in_.. and add_to_...
	// can be combined: find_or_add_...
	add_to_ino_dev_hashtable(&source_stat, dest);
	}

	src_fd = open(source, O_RDONLY);
	if (src_fd == -1) {
	bb_perror_msg("cannot open '%s'", source);
	return -1;
	}

	// POSIX: if exists and -i, ask (w/o -i assume yes).
	// Then open w/o EXCL.
	// If open still fails and -f, try unlink, then try open again.
	// Result: a mess:
	// If dest is a softlink, we overwrite softlink's 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...
	dst_fd = open(dest, (flags & FILEUTILS_INTERACTIVE)
	? O_WRONLY\|O_CREAT\|O_TRUNC\|O_EXCL
	: O_WRONLY\|O_CREAT\|O_TRUNC, source_stat.st_mode);
	if (dst_fd == -1) {
	// We would not do POSIX insanity. -i asks,
	// then _unlinks_ the offender. Presto.
	// Or else we will end up having 3 open()s!
	ovr = retry_overwrite(dest, flags);
	if (ovr <= 0) {
	close(src_fd);
	return ovr;
	}
	dst_fd = open(dest, O_WRONLY\|O_CREAT\|O_TRUNC, source_stat.st_mode);
	if (dst_fd == -1) {
	bb_perror_msg("cannot open '%s'", dest);
	close(src_fd);
	return -1;
	}
	}

	if (bb_copyfd_eof(src_fd, dst_fd) == -1)
	status = -1;
	if (close(dst_fd) < 0) {
	bb_perror_msg("cannot close '%s'", dest);
	status = -1;
	}
	if (close(src_fd) < 0) {
	bb_perror_msg("cannot close '%s'", source);
	status = -1;
	}

	} else 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)
	\|\| S_ISLNK(source_stat.st_mode)
	) {
	// We are lazy here, a bit lax with races...
	if (dest_exists) {
	ovr = retry_overwrite(dest, flags);
	if (ovr <= 0)
	return ovr;
	}
	if (S_ISFIFO(source_stat.st_mode)) {
	if (mkfifo(dest, source_stat.st_mode) < 0) {
	bb_perror_msg("cannot create fifo '%s'", dest);
	return -1;
	}
	} else if (S_ISLNK(source_stat.st_mode)) {
	char *lpath;

	lpath = xreadlink(source);
	if (symlink(lpath, dest) < 0) {
	bb_perror_msg("cannot create symlink '%s'", dest);
	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("cannot preserve %s of '%s'", "ownership", dest);

	return 0;

	} else {
	if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) {
	bb_perror_msg("cannot create '%s'", dest);
	return -1;
	}
	}
	} else {
	bb_error_msg("internal error: unrecognized file type");
	return -1;
	}

	preserve_status:

	if (flags & FILEUTILS_PRESERVE_STATUS
	/* Cannot happen: */
	/* && !(flags & (FILEUTILS_MAKE_SOFTLINK\|FILEUTILS_MAKE_HARDLINK)) */
	) {
	struct utimbuf times;

	times.actime = source_stat.st_atime;
	times.modtime = source_stat.st_mtime;
	if (utime(dest, &times) < 0)
	bb_perror_msg("cannot 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("cannot preserve %s of '%s'", "ownership", dest);
	}
	if (chmod(dest, source_stat.st_mode) < 0)
	bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest);
	}

	return status;
	}