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;