Fix crash when reading the empty tree

[git.git] / tar-tree.c

diff --git a/tar-tree.c b/tar-tree.c
index 11bbc81..fc60a90 100644 (file)
--- a/tar-tree.c
+++ b/tar-tree.c
@@ -3,7 +3,7 @@
  */
 #include <time.h>
 #include "cache.h"
-#include "diff.h"
+#include "tree-walk.h"
 #include "commit.h"
 #include "strbuf.h"
 #include "tar.h"
@@ -94,7 +94,6 @@ static void write_blocked(void *buf, unsigned long size)
        }
        if (size) {
                memcpy(block + offset, buf, size);
-               buf += size;
                offset += size;
        }
        tail = offset % RECORDSIZE;
@@ -161,6 +160,16 @@ static unsigned int ustar_header_chksum(const struct ustar_header *header)
        return chksum;
 }
 
+static int get_path_prefix(const struct strbuf *path, int maxlen)
+{
+       int i = path->len;
+       if (i > maxlen)
+               i = maxlen;
+       while (i > 0 && path->buf[i] != '/')
+               i--;
+       return i;
+}
+
 static void write_entry(const unsigned char *sha1, struct strbuf *path,
                         unsigned int mode, void *buffer, unsigned long size)
 {
@@ -195,9 +204,17 @@ static void write_entry(const unsigned char *sha1, struct strbuf *path,
                        return;
                }
                if (path->len > sizeof(header.name)) {
-                       sprintf(header.name, "%s.data", sha1_to_hex(sha1));
-                       strbuf_append_ext_header(&ext_header, "path",
-                                                path->buf, path->len);
+                       int plen = get_path_prefix(path, sizeof(header.prefix));
+                       int rest = path->len - plen - 1;
+                       if (plen > 0 && rest <= sizeof(header.name)) {
+                               memcpy(header.prefix, path->buf, plen);
+                               memcpy(header.name, path->buf + plen + 1, rest);
+                       } else {
+                               sprintf(header.name, "%s.data",
+                                       sha1_to_hex(sha1));
+                               strbuf_append_ext_header(&ext_header, "path",
+                                                        path->buf, path->len);
+                       }
                } else
                        memcpy(header.name, path->buf, path->len);
        }
@@ -296,6 +313,7 @@ int main(int argc, char **argv)
        current_path.len = current_path.eof = 0;
 
        setup_git_directory();
+       git_config(git_default_config);
 
        switch (argc) {
        case 3:
@@ -317,7 +335,7 @@ int main(int argc, char **argv)
        } else
                archive_time = time(NULL);
 
-       tree.buf = read_object_with_reference(sha1, "tree", &tree.size,
+       tree.buf = read_object_with_reference(sha1, tree_type, &tree.size,
                                              tree_sha1);
        if (!tree.buf)
                die("not a reference to a tag, commit or tree object: %s",