Previous code would fail on partial write, EINTR, and ENOSPC.
Upon any of the above errors, this patch tries next tempdir in list,
if list of tempdirs provided by config option server.upload-dirs
"Problem when uploading large files"
See doc/config/lighttpd.conf for explanation of listen() backlog queue
Additionally, mod_fastcgi and mod_scgi backend servers can now also be
configured with separate listen-backlog settings per server
"add server.listen-backlog option instead of hard-coded value (128 * 8) for listen()"
"Don't disable backend when overloaded"
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
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
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.
"Serving a file that is getting updated can cause an empty response or incorrect content-length error"