[pacman-dev] [PATCH 1/1] libalpm: fix resuming after HTTP error

[Hung-I Wang]

`curl_retry_next_server` tries to resume a download whenever possible
(introduced in 8bf17b2) even if its preceding HTTP request returns an
error (with status code >= 400, e.g. 404 when a mirror is only partially
synced).

It may result in a corrupted package if the preceding HTTP response with
error carries a non-empty body, which is then written to a tempfile as
if it is part of the package binary.

By activating `CURLOPT_FAILONERROR`, the tempfile won't be written
unless the HTTP response indicates a successful status.

Signed-off-by: Hung-I Wang <whygowe at gmail.com>
---
 lib/libalpm/dload.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/libalpm/dload.c b/lib/libalpm/dload.c
index 2d8b4d6d..faa3d9f2 100644
--- a/lib/libalpm/dload.c
+++ b/lib/libalpm/dload.c
@@ -338,6 +338,7 @@ static void curl_set_handle_opts(CURL *curl, struct dload_payload *payload)
 	curl_easy_setopt(curl, CURLOPT_TCP_KEEPINTVL, 60L);
 	curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
 	curl_easy_setopt(curl, CURLOPT_PRIVATE, (void *)payload);
+	curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1);
 
 	_alpm_log(handle, ALPM_LOG_DEBUG, "%s: url is %s\n",
 		payload->remote_name, payload->fileurl);
@@ -427,7 +428,8 @@ static int curl_retry_next_server(CURLM *curlm, CURL *curl, struct dload_payload
 	len = strlen(server) + strlen(payload->filepath) + 2;
 	MALLOC(payload->fileurl, len, RET_ERR(handle, ALPM_ERR_MEMORY, -1));
 	snprintf(payload->fileurl, len, "%s/%s", server, payload->filepath);
-
+	_alpm_log(handle, ALPM_LOG_DEBUG, "%s: url is %s\n",
+		payload->remote_name, payload->fileurl);
 
 	fflush(payload->localf);
 
@@ -496,6 +498,7 @@ static int curl_check_finished_download(CURLM *curlm, CURLMsg *msg,
 	/* was it a success? */
 	switch(curlerr) {
 		case CURLE_OK:
+		case CURLE_HTTP_RETURNED_ERROR:
 			/* get http/ftp response code */
 			_alpm_log(handle, ALPM_LOG_DEBUG, "%s: response code %ld\n",
 					payload->remote_name, payload->respcode);
-- 
2.31.1