cp: add support for -s, -l. Fix free(nonmalloc) bug.

    Add doc on POSIX's rules on -i and -f (insane!).
ln: make "ln dangling_symlink new_link" work.

1 files changed, 126 insertions, 84 deletions

diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index bd9c9f7a2..0135831fe 100644
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -10,31 +10,53 @@
 
 #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 dest_exists = 0;
 	int status = 0;
+	signed char dest_exists = 0;
+	signed char ovr;
 
-	if ((!(flags & FILEUTILS_DEREFERENCE) &&
-			lstat(source, &source_stat) < 0) ||
-			((flags & FILEUTILS_DEREFERENCE) &&
-			 stat(source, &source_stat) < 0)) {
-		bb_perror_msg("%s", source);
+#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("unable to stat `%s'", dest);
+			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);
+		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;
@@ -46,14 +68,14 @@ int copy_file(const char *source, const char *dest, int flags)
 		mode_t saved_umask = 0;
 
 		if (!(flags & FILEUTILS_RECUR)) {
-			bb_error_msg("%s: omitting directory", source);
+			bb_error_msg("omitting directory '%s'", source);
 			return -1;
 		}
 
 		/* Create DEST.  */
 		if (dest_exists) {
 			if (!S_ISDIR(dest_stat.st_mode)) {
-				bb_error_msg("`%s' is not a directory", dest);
+				bb_error_msg("target '%s' is not a directory", dest);
 				return -1;
 			}
 		} else {
@@ -67,7 +89,7 @@ int copy_file(const char *source, const char *dest, int flags)
 
 			if (mkdir(dest, mode) < 0) {
 				umask(saved_umask);
-				bb_perror_msg("cannot create directory `%s'", dest);
+				bb_perror_msg("cannot create directory '%s'", dest);
 				return -1;
 			}
 
@@ -75,7 +97,8 @@ int copy_file(const char *source, const char *dest, int flags)
 		}
 
 		/* Recursively copy files in SOURCE.  */
-		if ((dp = opendir(source)) == NULL) {
+		dp = opendir(source);
+		if (dp == NULL) {
 			status = -1;
 			goto preserve_status;
 		}
@@ -84,7 +107,7 @@ int copy_file(const char *source, const char *dest, int flags)
 			char *new_source, *new_dest;
 
 			new_source = concat_subpath_file(source, d->d_name);
-			if(new_source == NULL)
+			if (new_source == NULL)
 				continue;
 			new_dest = concat_path_file(dest, d->d_name);
 			if (copy_file(new_source, new_dest, flags) < 0)
@@ -92,103 +115,119 @@ int copy_file(const char *source, const char *dest, int flags)
 			free(new_source);
 			free(new_dest);
 		}
-		/* closedir have only EBADF error, but "dp" not changes */
 		closedir(dp);
 
-		if (!dest_exists &&
-				chmod(dest, source_stat.st_mode & ~saved_umask) < 0) {
-			bb_perror_msg("unable to change permissions of `%s'", dest);
+		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 (S_ISREG(source_stat.st_mode) ||
-		   (S_ISLNK(source_stat.st_mode) && (flags & FILEUTILS_DEREFERENCE)))
-	{
+
+	} 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 & FILEUTILS_DEREFERENCE) &&
-					is_in_ino_dev_hashtable(&source_stat, &link_name)) {
+			if (!FLAGS_DEREF
+			 && is_in_ino_dev_hashtable(&source_stat, &link_name)
+			) {
 				if (link(link_name, dest) < 0) {
-					bb_perror_msg("unable to link `%s'", dest);
-					return -1;
+					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("unable to open `%s'", source);
-			return(-1);
+			bb_perror_msg("cannot open '%s'", source);
+			return -1;
 		}
 
-		if (dest_exists) {
-			if (flags & FILEUTILS_INTERACTIVE) {
-				fprintf(stderr, "%s: overwrite `%s'? ", applet_name, dest);
-				if (!bb_ask_confirmation()) {
-					close (src_fd);
-					return 0;
-				}
-			}
-
-			dst_fd = open(dest, O_WRONLY|O_TRUNC);
-			if (dst_fd == -1) {
-				if (!(flags & FILEUTILS_FORCE)) {
-					bb_perror_msg("unable to open `%s'", dest);
-					close(src_fd);
-					return -1;
-				}
-
-				if (unlink(dest) < 0) {
-					bb_perror_msg("unable to remove `%s'", dest);
-					close(src_fd);
-					return -1;
-				}
-
-				goto dest_removed;
+		// 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;
 			}
-		} else {
-dest_removed:
-			dst_fd = open(dest, O_WRONLY|O_CREAT, source_stat.st_mode);
+			dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode);
 			if (dst_fd == -1) {
-				bb_perror_msg("unable to open `%s'", dest);
+				bb_perror_msg("cannot open '%s'", dest);
 				close(src_fd);
-				return(-1);
+				return -1;
 			}
 		}
 
 		if (bb_copyfd_eof(src_fd, dst_fd) == -1)
 			status = -1;
-
 		if (close(dst_fd) < 0) {
-			bb_perror_msg("unable to close `%s'", dest);
+			bb_perror_msg("cannot close '%s'", dest);
 			status = -1;
 		}
-
 		if (close(src_fd) < 0) {
-			bb_perror_msg("unable to close `%s'", source);
+			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)) {
 
+	} 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) {
-			if((flags & FILEUTILS_FORCE) == 0) {
-				fprintf(stderr, "`%s' exists\n", dest);
-				return -1;
-			}
-			if(unlink(dest) < 0) {
-				bb_perror_msg("unable to remove `%s'", dest);
-				return -1;
-			}
+			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);
+				bb_perror_msg("cannot create fifo '%s'", dest);
 				return -1;
 			}
 		} else if (S_ISLNK(source_stat.st_mode)) {
@@ -196,20 +235,21 @@ dest_removed:
 
 			lpath = xreadlink(source);
 			if (symlink(lpath, dest) < 0) {
-				bb_perror_msg("cannot create symlink `%s'", dest);
+				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("unable to preserve ownership of `%s'", dest);
+					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("unable to create `%s'", dest);
+				bb_perror_msg("cannot create '%s'", dest);
 				return -1;
 			}
 		}
@@ -218,22 +258,24 @@ dest_removed:
 		return -1;
 	}
 
-preserve_status:
+ preserve_status:
 
-	if (flags & FILEUTILS_PRESERVE_STATUS) {
+	if (flags & FILEUTILS_PRESERVE_STATUS
+	/* Cannot happen: */
+	/* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */
+	) {
 		struct utimbuf times;
-		char *msg="unable to preserve %s of `%s'";
 
 		times.actime = source_stat.st_atime;
 		times.modtime = source_stat.st_mtime;
 		if (utime(dest, &times) < 0)
-			bb_perror_msg(msg, "times", dest);
+			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(msg, "ownership", dest);
+			bb_perror_msg("cannot preserve %s of '%s'", "ownership", dest);
 		}
 		if (chmod(dest, source_stat.st_mode) < 0)
-			bb_perror_msg(msg, "permissions", dest);
+			bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest);
 	}
 
 	return status;