Send a clone file with its size in whole batches

The dumb transport read a pack four kilobytes at a time through stdio
and sent it without a length, so a client could not tell a cut-off
transfer from a complete one.

1 file changed, 18 insertions, 4 deletions

diff --git a/source/ui-clone.c b/source/ui-clone.c
index 2544e9f..833c170 100644
--- a/source/ui-clone.c
+++ b/source/ui-clone.c
@@ -95,11 +95,20 @@ static int path_is_safe(const char *path)
 	return 1;
 }
 
+/*
+ * The file is read in batches the size of the output buffer, so each one
+ * goes to the client in a single write, and its size is sent ahead so the
+ * client can tell a cut-off transfer from a complete one.
+ */
 static void send_file(const char *path)
 {
+	static char buf[HTML_BATCH];
 	struct stat st;
+	ssize_t got;
+	int fd;
 
-	if (stat(path, &st)) {
+	fd = open(path, O_RDONLY);
+	if (fd < 0) {
 		switch (errno) {
 		case ENOENT:
 			cgit_print_error_page(404, "Not Found", "Not found");
@@ -112,8 +121,10 @@ static void send_file(const char *path)
 		}
 		return;
 	}
-	// fopen opens a directory on most systems and reads nothing from it.
-	if (!S_ISREG(st.st_mode)) {
+	// open succeeds on a directory on most systems and reads nothing from
+	// it.
+	if (fstat(fd, &st) || !S_ISREG(st.st_mode)) {
+		close(fd);
 		cgit_print_error_page(404, "Not Found", "Not found");
 		return;
 	}
@@ -123,8 +134,11 @@ static void send_file(const char *path)
 	ctx.page.filename = path;
 	skip_prefix(path, ctx.repo->path, &ctx.page.filename);
 	skip_prefix(ctx.page.filename, "/", &ctx.page.filename);
+	ctx.page.size = st.st_size;
 	cgit_print_http_headers();
-	html_include(path);
+	while ((got = xread(fd, buf, sizeof(buf))) > 0)
+		html_raw(buf, got);
+	close(fd);
 }
 
 void cgit_clone_info(void)