Fix version to memory download

In the case where the swupd_download_version_to_memory callback was run
multiple times, it would overwrite previous data instead of appending.

Correct this behavior by keeping track of data written so far in the
struct passed to the callback.

Makefile.am

@@ -152,6 +152,7 @@ dist_check_SCRIPTS = \
 	test/functional/checkupdate/new-version/test.bats \
 	test/functional/checkupdate/no-server-content/test.bats \
 	test/functional/checkupdate/no-target-content/test.bats \
+	test/functional/checkupdate/slow-server/test.bats \
 	test/functional/checkupdate/version-match/test.bats \
 	test/functional/hashdump/file-hash/test.bats \
 	test/functional/hashdump/file-hash-no-path-prefix/test.bats \

src/curl.c

@@ -51,6 +51,11 @@ static CURL *curl = NULL;
 static int curr_version = -1;
 static int req_version = -1;
 
+struct version_container {
+	size_t offset;
+	char *version;
+};
+
 int swupd_curl_init(void)
 {
 	CURLcode curl_ret;
@@ -143,15 +148,16 @@ double swupd_query_url_content_size(char *url)
 
 static size_t swupd_download_version_to_memory(void *ptr, size_t size, size_t nmemb, void *userdata)
 {
-	char *tmp_version = (char *)userdata;
+	struct version_container *tmp_version = (struct version_container *)userdata;
 	size_t data_len = size * nmemb;
 
-	if (data_len >= LINE_MAX) {
+	if (data_len + tmp_version->offset >= LINE_MAX) {
 		return 0;
 	}
 
-	memcpy(tmp_version, ptr, data_len);
-	tmp_version[data_len] = '\0';
+	memcpy(tmp_version->version + tmp_version->offset, ptr, data_len);
+	tmp_version->version[data_len + tmp_version->offset] = '\0';
+	tmp_version->offset += data_len;
 
 	return data_len;
 }
@@ -251,6 +257,9 @@ int swupd_curl_get_file(const char *url, char *filename, struct file *file,
 			goto exit;
 		}
 	} else {
+		struct version_container vc = { 0 };
+		vc.version = in_memory_version_string;
+
 		// only download latest version number, storing in the provided pointer
 		printf("Attempting to download version string to memory\n");
 
@@ -258,7 +267,7 @@ int swupd_curl_get_file(const char *url, char *filename, struct file *file,
 		if (curl_ret != CURLE_OK) {
 			goto exit;
 		}
-		curl_ret = curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)in_memory_version_string);
+		curl_ret = curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)&vc);
 		if (curl_ret != CURLE_OK) {
 			goto exit;
 		}

src/version.c

@@ -41,7 +41,7 @@ int get_latest_version(void)
 	int ret = 0;
 	char *tmp_version;
 
-	tmp_version = malloc(LINE_MAX);
+	tmp_version = calloc(LINE_MAX, 1);
 	if (tmp_version == NULL) {
 		abort();
 	}

test/functional/checkupdate/slow-server/server.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+
+import http.server as server
+import sys
+import time
+
+
+class SlowResponse(server.BaseHTTPRequestHandler):
+    """Handler that returns data with a set delay between writes"""
+    def do_GET(self):
+        self.send_response(200)
+        self.send_header("Content-type", "text/html")
+        self.end_headers()
+        response = "99990"
+        delay = 0.00001 # seconds
+        for c in response:
+            self.wfile.write(str.encode(c))
+            time.sleep(delay)
+
+
+if __name__ == '__main__':
+    print(sys.argv)
+    addr = ('', int(sys.argv[1]))
+    httpd = server.HTTPServer(addr, SlowResponse)
+    httpd.serve_forever()

test/functional/checkupdate/slow-server/target-dir/usr/lib/os-release

@@ -0,0 +1,9 @@
+NAME="Clear Linux Software for Intel Architecture"
+VERSION=1
+ID=clear-linux-os
+VERSION_ID=10
+PRETTY_NAME="Clear Linux Software for Intel Architecture"
+ANSI_COLOR="1;35"
+HOME_URL="https://clearlinux.org"
+SUPPORT_URL="https://clearlinux.org"
+BUG_REPORT_URL="https://bugs.clearlinux.org/jira"

test/functional/checkupdate/slow-server/test.bats

@@ -0,0 +1,34 @@
+#!/usr/bin/env bats
+
+load "../../swupdlib"
+
+server_pid=""
+port=""
+
+setup() {
+  for i in $(seq 8080 8180); do
+    "$DIR/server.py" $i &
+    sleep .2
+    server_pid=$!
+    if [ -d /proc/$server_pid ]; then
+      port=$i
+      break
+    fi
+  done
+}
+
+teardown() {
+  kill $server_pid
+}
+
+@test "check-update with a slow server" {
+  slow_opts="-p $DIR/target-dir -F staging -u http://localhost:$port/"
+  run sudo sh -c "$SWUPD check-update $slow_opts"
+
+  echo "$output"
+  [ "${lines[2]}" = "Querying server version." ]
+  [ "${lines[3]}" = "Attempting to download version string to memory" ]
+  [ "${lines[4]}" = "There is a new OS version available: 99990" ]
+}
+
+# vi: ft=sh ts=8 sw=2 sts=2 et tw=80