From a65c57a54812fa44a8e1b6e846f69ac6e314f5d1 Mon Sep 17 00:00:00 2001 From: Glenn Strauss Date: Wed, 30 Mar 2016 06:39:33 -0400 Subject: [core] open fd when appending file to cq (fixes #2655) http_chunk_append_file() opens fd when appending file to chunkqueue. Defers calculation of content length until response is finished. This reduces race conditions pertaining to stat() and then (later) open(), when the result of the stat() was used for Content-Length or to generate chunked headers. Note: this does not change how lighttpd handles files that are modified in-place by another process after having been opened by lighttpd -- don't do that. This *does* improve handling of files that are frequently modified via a temporary file and then atomically renamed into place. mod_fastcgi has been modified to use http_chunk_append_file_range() with X-Sendfile2 and will open the target file multiple times if there are multiple ranges. Note: (future todo) not implemented for chunk.[ch] interfaces used by range requests in mod_staticfile or by mod_ssi. Those uses could lead to too many open fds. For mod_staticfile, limits should be put in place for max number of ranges accepted by mod_staticfile. For mod_ssi, limits would need to be placed on the maximum number of includes, and the primary SSI file split across lots of SSI directives should either copy the pieces or perhaps chunk.h could be extended to allow for an open fd to be shared across multiple chunks. Doing either of these would improve the performance of SSI since they would replace many file opens on the pieces of the SSI file around the SSI directives. x-ref: "Serving a file that is getting updated can cause an empty response or incorrect content-length error" https://redmine.lighttpd.net/issues/2655 github: Closes #49 --- src/http_chunk.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'src/http_chunk.h') diff --git a/src/http_chunk.h b/src/http_chunk.h index eaa771a4..266e24ce 100644 --- a/src/http_chunk.h +++ b/src/http_chunk.h @@ -7,7 +7,8 @@ void http_chunk_append_mem(server *srv, connection *con, const char * mem, size_t len); /* copies memory */ void http_chunk_append_buffer(server *srv, connection *con, buffer *mem); /* may reset "mem" */ -void http_chunk_append_file(server *srv, connection *con, buffer *fn, off_t offset, off_t len); /* copies "fn" */ +int http_chunk_append_file(server *srv, connection *con, buffer *fn); /* copies "fn" */ +int http_chunk_append_file_range(server *srv, connection *con, buffer *fn, off_t offset, off_t len); /* copies "fn" */ void http_chunk_close(server *srv, connection *con); #endif -- cgit v1.2.1