difftool: address a couple of resource/memory leaks

This change plugs a couple of memory leaks and makes sure that the file
descriptor is closed in run_dir_diff().

Spotted by Coverity.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/difftool.c

@@ -226,6 +226,7 @@ static void changed_files(struct hashmap *result, const char *index_path,
 		hashmap_entry_init(entry, strhash(buf.buf));
 		hashmap_add(result, entry);
 	}
+	fclose(fp);
 	if (finish_command(&diff_files))
 		die("diff-files did not exit properly");
 	strbuf_release(&index_env);
@@ -439,8 +440,10 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 		}
 
 		if (lmode && status != 'C') {
-			if (checkout_path(lmode, &loid, src_path, &lstate))
-				return error("could not write '%s'", src_path);
+			if (checkout_path(lmode, &loid, src_path, &lstate)) {
+				ret = error("could not write '%s'", src_path);
+				goto finish;
+			}
 		}
 
 		if (rmode && !S_ISLNK(rmode)) {
@@ -456,9 +459,12 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 			hashmap_add(&working_tree_dups, entry);
 
 			if (!use_wt_file(workdir, dst_path, &roid)) {
-				if (checkout_path(rmode, &roid, dst_path, &rstate))
-					return error("could not write '%s'",
-						     dst_path);
+				if (checkout_path(rmode, &roid, dst_path,
+						  &rstate)) {
+					ret = error("could not write '%s'",
+						    dst_path);
+					goto finish;
+				}
 			} else if (!is_null_oid(&roid)) {
 				/*
 				 * Changes in the working tree need special
@@ -473,10 +479,12 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 						ADD_CACHE_JUST_APPEND);
 
 				add_path(&rdir, rdir_len, dst_path);
-				if (ensure_leading_directories(rdir.buf))
-					return error("could not create "
-						     "directory for '%s'",
-						     dst_path);
+				if (ensure_leading_directories(rdir.buf)) {
+					ret = error("could not create "
+						    "directory for '%s'",
+						    dst_path);
+					goto finish;
+				}
 				add_path(&wtdir, wtdir_len, dst_path);
 				if (symlinks) {
 					if (symlink(wtdir.buf, rdir.buf)) {
@@ -497,13 +505,15 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 		}
 	}
 
+	fclose(fp);
+	fp = NULL;
 	if (finish_command(&child)) {
 		ret = error("error occurred running diff --raw");
 		goto finish;
 	}
 
 	if (!i)
-		return 0;
+		goto finish;
 
 	/*
 	 * Changes to submodules require special treatment.This loop writes a
@@ -626,6 +636,9 @@ static int run_dir_diff(const char *extcmd, int symlinks, const char *prefix,
 		exit_cleanup(tmpdir, rc);
 
 finish:
+	if (fp)
+		fclose(fp);
+
 	free(lbase_dir);
 	free(rbase_dir);
 	strbuf_release(&ldir);