Minor API tweak: The format-specific write_header function now sets

the size in the archive_entry object to zero if that format doesn't
store a body for that file type.  This allows the client to determine
whether or not it should feed the file body to the archive.  In
particular, cpio stores the file body for hardlinks, tar and shar
don't.  With this change, bsdtar now correctly archives hardlinks in all
supported formats.

While I'm here, make shar output be more aggressive about creating directories.
Before this, commands such as:
    bsdtar -cv -F shar  some/explicit/path/to/a/file
wouldn't create the directory.  Some simple logic to remember the last
directory creation helps reduce unnecessary mkdirs here.

At this point, I think the only flaw in libarchive's cpio support is
the failure to recognize hardlinks when reading.

1 files changed, 70 insertions, 21 deletions

diff --git a/lib/libarchive/archive_write_set_format_shar.c b/lib/libarchive/archive_write_set_format_shar.c
index 52f5509..676f997 100644
--- a/lib/libarchive/archive_write_set_format_shar.c
+++ b/lib/libarchive/archive_write_set_format_shar.c
@@ -56,6 +56,7 @@ struct shar {
 	int			 end_of_line;
 	struct archive_entry	*entry;
 	int			 has_data;
+	char			*last_dir;
 	char			 outbuff[1024];
 	size_t			 outbytes;
 	size_t			 outpos;
@@ -130,6 +131,7 @@ archive_write_shar_header(struct archive *a, struct archive_entry *entry)
 {
 	const char *linkname;
 	const char *name;
+	char *p, *pp;
 	struct shar *shar;
 	const struct stat *st;
 
@@ -140,28 +142,74 @@ archive_write_shar_header(struct archive *a, struct archive_entry *entry)
 		shar->wrote_header = 1;
 	}
 
-	/* Save the entry for the closing */
+	/* Save the entry for the closing. */
 	if (shar->entry)
 		archive_entry_free(shar->entry);
 	shar->entry = archive_entry_clone(entry);
 	name = archive_entry_pathname(entry);
 	st = archive_entry_stat(entry);
 
+	/* Handle some preparatory issues. */
+	switch(st->st_mode & S_IFMT) {
+	case S_IFREG:
+		/* Only regular files have non-zero size. */
+		break;
+	case S_IFDIR:
+	case S_IFIFO:
+	case S_IFCHR:
+	case S_IFBLK:
+		/* All other file types have zero size in the archive. */
+		archive_entry_set_size(entry, 0);
+		break;
+	default:
+		archive_entry_set_size(entry, 0);
+		if (archive_entry_hardlink(entry) == NULL &&
+		    archive_entry_symlink(entry) == NULL) {
+			archive_set_error(a, -1,
+			    "shar format cannot archive this");
+			return (ARCHIVE_WARN);
+		}
+	}
+
+	/* Stock preparation for all file types. */
+	shar_printf(a, "echo x %s\n", name);
+
+	if (!S_ISDIR(st->st_mode)) {
+		/* Try to create the dir. */
+		p = strdup(name);
+		pp = strrchr(p, '/');
+		if (pp != NULL)
+			*pp = '\0';
+
+		if (shar->last_dir == NULL) {
+			shar_printf(a, "mkdir -p %s > /dev/null 2>&1\n", p);
+			shar->last_dir = p;
+		} else if (strcmp(p, shar->last_dir) == 0) {
+			/* We've already created this exact dir. */
+			free(p);
+		} else if (strlen(p) < strlen(shar->last_dir) &&
+		    strncmp(p, shar->last_dir, strlen(p)) == 0) {
+			/* We've already created a subdir. */
+			free(p);
+		} else {
+			shar_printf(a, "mkdir -p %s > /dev/null 2>&1\n", p);
+			free(shar->last_dir);
+			shar->last_dir = p;
+		}
+	}
+
+	/* Handle file-type specific issues. */
 	shar->has_data = 0;
-	if ((linkname = archive_entry_hardlink(entry)) != NULL) {
-		shar_printf(a, "echo x %s\n", name);
+	if ((linkname = archive_entry_hardlink(entry)) != NULL)
 		shar_printf(a, "ln -f %s %s\n", linkname, name);
-	} else if ((linkname = archive_entry_symlink(entry)) != NULL) {
-		shar_printf(a, "echo x %s\n", name);
+	else if ((linkname = archive_entry_symlink(entry)) != NULL)
 		shar_printf(a, "ln -fs %s %s\n", linkname, name);
-	} else {
+	else {
 		switch(st->st_mode & S_IFMT) {
 		case S_IFREG:
-			shar_printf(a, "echo x %s\n", name);
-			if (archive_entry_size(entry) == 0) {
+			if (archive_entry_size(entry) == 0)
 				shar_printf(a, "touch %s\n", name);
-				shar->has_data = 0;
-			} else {
+			else {
 				if (shar->dump) {
 					shar_printf(a,
 					    "uudecode -o %s << 'SHAR_END'\n",
@@ -180,36 +228,35 @@ archive_write_shar_header(struct archive *a, struct archive_entry *entry)
 			}
 			break;
 		case S_IFDIR:
-			shar_printf(a, "echo x %s\n", name);
 			shar_printf(a, "mkdir -p %s > /dev/null 2>&1\n", name);
+			/* Record that we just created this directory. */
+			if (shar->last_dir != NULL)
+				free(shar->last_dir);
+
+			shar->last_dir = strdup(name);
+			/* Trim a trailing '/'. */
+			pp = strrchr(shar->last_dir, '/');
+			if (pp != NULL && pp[1] == '\0')
+				*pp = '\0';
 			/*
 			 * TODO: Put dir name/mode on a list to be fixed
 			 * up at end of archive.
 			 */
 			break;
 		case S_IFIFO:
-			shar_printf(a, "echo x %s\n", name);
 			shar_printf(a, "mkfifo %s\n", name);
 			break;
 		case S_IFCHR:
-			shar_printf(a, "echo x %s\n", name);
 			shar_printf(a, "mknod %s c %d %d\n", name,
 			    archive_entry_devmajor(entry),
 			    archive_entry_devminor(entry));
 			break;
 		case S_IFBLK:
-			shar_printf(a, "echo x %s\n", name);
 			shar_printf(a, "mknod %s b %d %d\n", name,
 			    archive_entry_devmajor(entry),
 			    archive_entry_devminor(entry));
 			break;
-		case S_IFSOCK:
-			archive_set_error(a, -1,
-			    "shar format cannot archive socket");
-			return (ARCHIVE_WARN);
 		default:
-			archive_set_error(a, -1,
-			    "shar format cannot archive this");
 			return (ARCHIVE_WARN);
 		}
 	}
@@ -395,8 +442,10 @@ archive_write_shar_finish(struct archive *a)
 		 * uncompressed data within gzip/bzip2 streams.
 		 */
 	}
-	if (shar->entry)
+	if (shar->entry != NULL)
 		archive_entry_free(shar->entry);
+	if (shar->last_dir != NULL)
+		free(shar->last_dir);
 	free(shar);
 	a->format_data = NULL;
 	return (ARCHIVE_OK);