There was a flaw in the way the threads was created. the main one was just used
to create all the others and just wait to exit. Now, it is used to run a poll
loop. So we only create nbthread-1 threads.
This also fixes a bug about the compression filter when there is only 1 thread
(nbthread == 1 or no threads support). The bug was in the way thread-local
resources was initialized. per-thread init/deinit callbacks were never called
for the main process. So, with nthread set to 1, some buffers remained
uninitialized.
Now, we use init_trash_buffers and deinit_trash_buffers to, respectively,
initialize and deinitialize trash buffers (trash, trash_buf1 and trash_buf2).
These functions have been introduced to be used by threads, to deal with
thread-local trash buffers.
The trash buffers are becoming increasingly complex to deal with due to
the code's modularity allowing some functions to be chained and causing
the same chunk buffers to be used multiple times along the chain, possibly
corrupting each other. In fact the trash were designed from scratch for
explicitly not surviving a function call but string manipulation makes
this impossible most of the time while not fullfilling the need for
reliable temporary chunks.
Here we introduce the ability to allocate a temporary trash chunk which
is reserved, so that it will not conflict with the trash chunks other
functions use, and will even support reentrant calls (eg: build_logline).
For this, we create a new pool which is exactly the size of a usual chunk
buffer plus the size of the chunk struct so that these chunks when allocated
are exactly the same size as the ones returned by get_trash_buffer(). These
chunks may fail so the caller must check them, and the caller is also
responsible for freeing them.
The code focuses on minimal changes and ease of reliable backporting
because it will be needed in stable versions in order to support next
patch.
Changed all the cases where the pointer passed to realloc is overwritten
by the pointer returned by realloc. The new function my_realloc2 has
been used except in function register_name. If register_name fails to
add a new variable because of an "out of memory" error, all the existing
variables remain valid. If we had used my_realloc2, the array of variables
would have been freed.
The recent addition of "show env" on the CLI has revealed an interesting
design bug. Chunks are supposed to support a negative length to indicate
that they carry no data. chunk_printf() sets this size to -1 if the string
is too large for the buffer. At a few places in the http engine we may end
up with trash.len = -1. But bi_putchk(), chunk_appendf() and a few other
chunks consumers don't consider this case as possible and will use such a
chunk, possibly restoring an invalid string or trying to copy -1 bytes.
This fix takes care of clarifying the situation in a backportable way
where such sizes are used, so that a negative length indicating an error
remains present until the chunk is reinitialized or overwritten. But a
cleaner design adjustment needs to be done so that there's a clear contract
on how to use these chunks. At first glance it doesn't seem *that* useful
to support negative sizes, so probably this is what should change.
This fix must be backported to 1.6 and 1.5.
They could match different strings as equal if the chunk was shorter
than the string. Those functions are currently only used for SSL's
certificate DN entry extract.
The get_trash_chunk() function is convenient and is sometimes used even
to get a temporary string. While the chunk is initialized, the string
may contain some random garbage that some code might retrieve if it uses
chunk->str directly without checking ->len. This is what happened in checks
after commit 25e2ab5 (MEDIUM: checks: centralize error reporting). It's not
easy to guess it at first so better pre-initialize the string with a zero.
At the moment, we need trash chunks almost everywhere and the only
correctly implemented one is in the sample code. Let's move this to
the chunks so that all other places can use this allocator.
Additionally, the get_trash_chunk() function now really returns two
different chunks. Previously it used to always overwrite the same
chunk and point it to a different buffer, which was a bit tricky
because it's not obvious that two consecutive results do alias each
other.
This function's naming was misleading as it is used to append data
at the end of a string, causing some surprizes when used for the
first time!
Add a chunk_printf() function which does what its name suggests.
It's sometimes needed to be able to compare a zero-terminated string with a
chunk, so we now have two functions to do that, one strcmp() equivalent and
one strcasecmp() equivalent.
