This commit is a large set of code changes and results in removal of
hundreds, perhaps thousands, of CPU instructions, a portion of which
are on hot code paths.
Most (buffer *) used by lighttpd are not NULL, especially since buffers
were inlined into numerous larger structs such as request_st and chunk.
In the small number of instances where that is not the case, a NULL
check is often performed earlier in a function where that buffer is
later used with a buffer_* func. In the handful of cases that remained,
a NULL check was added, e.g. with r->http_host and r->conf.server_tag.
- check for empty strings at config time and set value to NULL if blank
string will be ignored at runtime; at runtime, simple pointer check
for NULL can be used to check for a value that has been set and is not
blank ("")
- use buffer_is_blank() instead of buffer_string_is_empty(),
and use buffer_is_unset() instead of buffer_is_empty(),
where buffer is known not to be NULL so that NULL check can be skipped
- use buffer_clen() instead of buffer_string_length() when buffer is
known not to be NULL (to avoid NULL check at runtime)
- use buffer_truncate() instead of buffer_string_set_length() to
truncate string, and use buffer_extend() to extend
Examples where buffer known not to be NULL:
- cpv->v.b from config_plugin_values_init is not NULL if T_CONFIG_BOOL
(though we might set it to NULL if buffer_is_blank(cpv->v.b))
- address of buffer is arg (&foo)
(compiler optimizer detects this in most, but not all, cases)
- buffer is checked for NULL earlier in func
- buffer is accessed in same scope without a NULL check (e.g. b->ptr)
internal behavior change:
callers must not pass a NULL buffer to some funcs.
- buffer_init_buffer() requires non-null args
- buffer_copy_buffer() requires non-null args
- buffer_append_string_buffer() requires non-null args
- buffer_string_space() requires non-null arg
create API in chunk.[ch] for writing a chunk to an fd
(pull similar code from mod_cgi and mod_webdav)
This new API is intended for use on request body input, which is
written to size-limited temporary files controlled by lighttpd and
written to files or pipes.
(network_backend_write() is for writing chunkqueues to sockets)
FreeBSD provides an API similar to Linux copy_file_range()
but uses off_t instead of loff_t in the syscall.
off_t is equivalent to off64_t when lighttpd is built with LFS
(and lighttpd is built with LFS enabled by default)
replace /* fall through */ comment with __attribute_fallthrough__ macro
Note: not adding attribute to code with external origins:
xxhash.h (algo_xxhash.h)
ls-hpack/lshpack.c
so to avoid warnings, may need to compile with -Wno-implicit-fallthrough
more consistent use of shared code config_plugin_value_tobool()
(thx tow-conf)
x-ref:
"The on/off keywords in boolean configuration options is inconsistent, which might be misleading and error-prone."
https://redmine.lighttpd.net/issues/3036
r->con->reqbody_read() replaces connection_handle_read_post_state()
future: might provide different callbacks for request body with
Content-Length versus request body sent via Transfer-Encoding: chunked
fix fallback if linkat() fails
check at startup if /proc/self/fd is present on systems with O_TMPFILE
(containers might not mount /proc)
x-ref:
"mod_webdav - PUT files with < 64kb Content-Length reults in zero length file"
https://redmine.lighttpd.net/boards/2/topics/9273
fix theoretical NULL dereference identified by Coverity Scan
possible for PROPFIND with specific atypical choices in lighttpd.conf:
- possible for getcontenttype if no content type matches resource
and no default type configured in lighttpd.conf
- possible for getetag if etag disabled in lighttpd.conf
