X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=builtin-tar-tree.c;h=58a8ccd4d6af0d755fca28b06a12ca9b8efa5300;hb=0e8a002c59cbaca692dac81320be44c965588291;hp=7663b9bd8e5f10ee45e34752f631d435687cf1b3;hpb=17cf250aff26d3baa6b311a3404f1a932e16cf17;p=git.git

diff --git a/builtin-tar-tree.c b/builtin-tar-tree.c
index 7663b9bd..58a8ccd4 100644
--- a/builtin-tar-tree.c
+++ b/builtin-tar-tree.c
@@ -402,3 +402,28 @@ int cmd_tar_tree(int argc, const char **argv, char **envp)
 		return remote_tar(argc, argv);
 	return generate_tar(argc, argv, envp);
 }
+
+/* ustar header + extended global header content */
+#define HEADERSIZE (2 * RECORDSIZE)
+
+int cmd_get_tar_commit_id(int argc, const char **argv, char **envp)
+{
+	char buffer[HEADERSIZE];
+	struct ustar_header *header = (struct ustar_header *)buffer;
+	char *content = buffer + RECORDSIZE;
+	ssize_t n;
+
+	n = xread(0, buffer, HEADERSIZE);
+	if (n < HEADERSIZE)
+		die("git-get-tar-commit-id: read error");
+	if (header->typeflag[0] != 'g')
+		return 1;
+	if (memcmp(content, "52 comment=", 11))
+		return 1;
+
+	n = xwrite(1, content + 11, 41);
+	if (n < 41)
+		die("git-get-tar-commit-id: write error");
+
+	return 0;
+}