Add hard link support to gensquashfs and tar2sqfs

In libtar, set a special flag if the header is actually a hard link.

In tar2sqfs, create a hard link node and skip the rest for hard links.
Also refues to set the root attributes from a hard link, it may refere
to a node that we have missed earlier, there is nothing else that we
can do here.

In fstree_from_file, add a "link" command for adding hard links.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

2 files changed, 15 insertions, 2 deletions

diff --git a/lib/fstree/fstree_from_file.c b/lib/fstree/fstree_from_file.c
index 9cdf9a1..bf11755 100644
--- a/lib/fstree/fstree_from_file.c
+++ b/lib/fstree/fstree_from_file.c
@@ -62,6 +62,19 @@ static int add_file(fstree_t *fs, const char *filename, size_t line_num,
 	return add_generic(fs, filename, line_num, path, basic, extra);
 }
 
+static int add_hard_link(fstree_t *fs, const char *filename, size_t line_num,
+			 const char *path, struct stat *basic, const char *extra)
+{
+	(void)basic;
+
+	if (fstree_add_hard_link(fs, path, extra) == NULL) {
+		fprintf(stderr, "%s: " PRI_SZ ": %s\n",
+			filename, line_num, strerror(errno));
+		return -1;
+	}
+	return 0;
+}
+
 static const struct {
 	const char *keyword;
 	unsigned int mode;
@@ -71,6 +84,7 @@ static const struct {
 } file_list_hooks[] = {
 	{ "dir", S_IFDIR, false, add_generic },
 	{ "slink", S_IFLNK, true, add_generic },
+	{ "link", 0, true, add_hard_link },
 	{ "nod", 0, true, add_device },
 	{ "pipe", S_IFIFO, false, add_generic },
 	{ "sock", S_IFSOCK, false, add_generic },
diff --git a/lib/tar/read_header.c b/lib/tar/read_header.c
index 7d209ae..f82f9a5 100644
--- a/lib/tar/read_header.c
+++ b/lib/tar/read_header.c
@@ -345,8 +345,7 @@ static int decode_header(const tar_header_t *hdr, unsigned int set_by_pax,
 		out->sb.st_mode |= S_IFREG;
 		break;
 	case TAR_TYPE_LINK:
-		/* XXX: hard links are not support yet */
-		out->sb.st_mode = S_IFLNK | 0777;
+		out->is_hard_link = true;
 		break;
 	case TAR_TYPE_SLINK:
 		out->sb.st_mode = S_IFLNK | 0777;