Upstream: better handling of invalid headers in cache files.
If cache file is truncated, it is possible that u->process_header()
will return NGX_AGAIN. Added appropriate handling of this case by
changing the error to NGX_HTTP_UPSTREAM_INVALID_HEADER.
Also, added appropriate logging of this and NGX_HTTP_UPSTREAM_INVALID_HEADER
cases at the "crit" level. Note that this will result in duplicate logging
in case of NGX_HTTP_UPSTREAM_INVALID_HEADER. While this is something better
to avoid, it is considered to be an overkill to implement cache-specific
error logging in u->process_header().
Additionally, u->buffer.start is now reset to be able to receive a new
response, and u->cache_status set to MISS to provide the value in the
$upstream_cache_status variable, much like it happens on other cache file
errors detected by ngx_http_file_cache_read(), instead of HIT, which is
believed to be misleading.
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 73a5882..b3580fe 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -582,6 +582,8 @@
if (rc == NGX_HTTP_UPSTREAM_INVALID_HEADER) {
rc = NGX_DECLINED;
r->cached = 0;
+ u->buffer.start = NULL;
+ u->cache_status = NGX_HTTP_CACHE_MISS;
}
if (ngx_http_upstream_cache_background_update(r, u) != NGX_OK) {
@@ -1059,8 +1061,16 @@
return NGX_ERROR;
}
+ if (rc == NGX_AGAIN) {
+ rc = NGX_HTTP_UPSTREAM_INVALID_HEADER;
+ }
+
/* rc == NGX_HTTP_UPSTREAM_INVALID_HEADER */
+ ngx_log_error(NGX_LOG_CRIT, r->connection->log, 0,
+ "cache file \"%s\" contains invalid header",
+ c->file.name.data);
+
/* TODO: delete file */
return rc;
