We don't need the pattern-specific args parsers anymore, make use of the
common parser instead. We still need to improve this by adding a validation
function to report abnormal argument values or combinations. We don't report
precise parsing errors yet but this was not previously done either.
arg_i was almost unused, and since we migrated to use struct arg everywhere,
the rare cases where arg_i was needed could be replaced by switching to
arg->type = ARGT_STOP.
A large number of ACLs make use of frontend, backend or table names in their
arguments, and fall back to the current proxy when no argument is passed. If
the expected capability is not available, the ACL silently fails at runtime.
Now we make all those names mandatory in the parser and we rely on
acl_find_targets() to replace the missing names with the holding proxy,
then to perform the appropriate tests, and to reject errors at parsing
time.
It is possible that some faulty configurations will get rejected from now
on, while they used to silently fail till now. This is the reason why this
change is marked as MAJOR.
Proxy names are now resolved when the config is parsed and not at runtime.
This means that errors will be caught for real instead of having an ACL
silently never match. Another benefit is that the fetch will be much faster
since the lookup will not have to be performed anymore, eg for all ACLs
based on explicitly named stick-tables.
However some buggy configurations which used to silently fail in the past
will now refuse to load, hence the MAJOR tag.
This function does not rely on the keyword anymore but just on its type.
It's much cleaner and much safer. It should be extended to do the same for
all PRX type arguments.
The types and minimal number of ACL keyword arguments are now stored in
their declaration. This will allow many more fantasies if some ACL use
several arguments or types.
Doing so required to rework all ACL keyword declarations to add two
parameters. So this was a good opportunity for a general cleanup and
to sort all entries in alphabetical order.
We still have two pending issues :
- parse_acl_expr() checks for errors but has no way to report them to
the user ;
- the types of some arguments are still not resolved and kept as strings
(eg: ARGT_FE/BE/TAB) for compatibility reasons, which must be resolved
in acl_find_targets()
The ACL parser now uses the argument parser to build a typed argument list.
Right now arguments are all strings and only one argument is supported since
this is what ACLs currently support.
make_arg_list() builds an array of typed arguments with their values,
that the caller describes how to parse. This will be used to support
multiple arguments for ACLs and patterns, which is currently problematic
and prevents ACLs and patterns from being merged. Up to 7 arguments types
may be enumerated in a single 32-bit word, including their number of
mandatory parts.
At the moment, these files are not used yet, they're only built. Note that
the 4-bit encoding for the type has left only one unused type!
Latest changes have made it possible to remove all differences between
request and response processing, making it worth merging request and
response ACL fetch functions to reduce code size.
Most likely with minor adaptation it will be possible to use the same hdr_*
functions to match in the response path, and cook_* for the response cookie
too.
ACLs are volatile since they require a fetch of request buffer data which is
then copied to a temporary shared place. The issue is minor though since auth
is generally checked very early.
All ACLs which need to process HTTP contents first call this function which
performs all the preliminary tests and also triggers the request parsing if
needed. A macro was written to simplify the code.
As a side effect, it's not required anymore to check for the HTTP ACL before
checking for HTTP contents.
This function will be called by all ACL fetch functions. Right now all ACL
fetch functions have to perform the exact same tests to check whether data
are available. Also, only one of them is able to actually parse an HTTP
request.
Using the prefetch function, it will be possible to try to parse a request
on the fly and to avoid the fetch if some data are missing. This will
significantly reduce the amount of tests in all ACL fetch functions.
This is more convenient and efficient than buf->p = b_ptr(buf, n);
It simply advances the buffer's pointer by <n> and trasfers that
amount of bytes from <in> to <out>. The BF_OUT_EMPTY flag is updated
accordingly.
A few occurrences of such computations in buffers.c and stream_sock.c
were updated to use b_adv(), which resulted in a small code shrink.
buffer_wrap_add was convenient for the migration but is not handy at all.
Let's have new wrappers that report input begin/end and output begin/end
instead.
It looks like we'll also need a b_adv(ofs) to advance a buffer's pointer.
buffer_ignore may only be used when the output of a buffer is empty,
but it's not granted it is always the case when sending HTTP error
responses. Better use buffer_cut_tail() instead, and use buffer_ignore
only on non-wrapping data.
The buffer pointer is now taken from the http_msg in the following
functions :
http_parse_chunk_size
http_forward_trailers
http_skip_chunk_crlf
Most internal pointers were converted to const as the result of the
operation.
The buffer pointer is now taken from the http_msg in the following functions :
- http_remove_header2
- http_header_add_tail
- http_header_add_tail2
- http_parse_connection_header
- http_change_connection_header
msg->sol is now a relative pointer just like all other ones. There is no
more absolute references to the buffer outside the struct buffer itself.
Next two cleanups should include removing buffer references to functions
which already have an msg, and removal of wrapping detection in request
and response parsing which cannot wrap by definition.
ACLs and patterns only rely on a struct http_msg and don't know the pointer
to the actual data. struct http_msg will soon only hold relative references
so that's not possible. We need http_msg to hold a reference to the struct
buffer before having relative pointers everywhere.
It is likely that doing so will also result in opportunities to simplify
a number of functions arguments. The following functions are already
candidate :
http_buffer_heavy_realign
http_capture_bad_message
http_change_connection_header
http_forward_trailers
http_header_add_tail
http_header_add_tail2
http_msg_analyzer
http_parse_chunk_size
http_parse_connection_header
http_remove_header2
http_send_name_header
http_skip_chunk_crlf
http_upgrade_v09_to_v10
These offsets were relative to the buffer itself. Now they're relative to
the buffer's origin (buf->p) which normally corresponds to the start of
current message.
This saves a big dependency between the HTTP message struct and the buffers.
It appeared during this change that ->col is not used anymore (it will have
to be removed). Next step is to turn ->eol and ->sol from absolute to relative.
The buffer's pointer <lr> was only used by HTTP parsers which also use a
struct http_msg to keep track of the parser's state. We've reached a point
where it makes no sense to keep ->lr in the buffer, as the split between
buffer and msg is only arbitrary for historical reasons.
This change ensures that touching buffers will not impact HTTP messages
anymore, making the buffers more content-agnostic. However, it becomes
very important not to forget to update msg->next when some data get
forwarded or moved (and in general each time buf->p is updated).
The new pointer in http_msg becomes relative to buffer->p so that
parsing multiple messages becomes easier. It is possible that at one
point ->som and ->next will be merged.
Note: http_parse_reqline() and http_parse_stsline() have been temporarily
modified to know the message starting point in the buffer (->p).
This change gets rid of buf->r which is always equal to buf->p + buf->i.
It removed some wrapping detection at a number of places, but required addition
of new relative offset computations at other locations. A large number of places
can be simplified now with extreme care, since most of the time, either the
pointer has to be computed once or we need a difference between the old ->w and
old ->r to compute free space. The cleanup will probably happen with the rewrite
of the buffer_input_* and buffer_output_* functions anyway.
buf->lr still has to move to the struct http_msg and be relative to buf->p
for the rework to be complete.
This change introduces the buffer's base pointer, which is the limit between
incoming and outgoing data. It's the point where the parsing should start
from. A number of computations have already been greatly simplified, but
more simplifications are expected to come from the removal of buf->r.
The changes appear good and have revealed occasional improper use of some
pointers. It is possible that this patch has introduced bugs or revealed
some, although preliminary testings tend to indicate that everything still
works as it should.
We don't have buf->l anymore. We have buf->i for pending data and
the total length is retrieved by adding buf->o. Some computation
already become simpler.
Despite extreme care, bugs are not excluded.
It's worth noting that msg->err_pos as set by HTTP request/response
analysers becomes relative to pending data and not to the beginning
of the buffer. This has not been completed yet so differences might
occur when outgoing data are left in the buffer.
Also add some thoughts about the existing and new design.
Note: an earlier design used the names "head" and "tail" for both sides
of the buffer, but it appears awkward as these words may be understood
in two forms (feed by head, output by tail, or make the newcomers wait
at the tail of the queue). Also there were already a few functions in the
code making use of either terminology. So better avoid this terminology
and use "input" and "output" instead.
Too many flags are stored in the transaction structure. Some flags are
clearly message-specific and exist in two versions (request and response).
Move them to a new "flags" field in the http_message struct instead.
There were a few unchecked write() calls in the debug code that cause
gcc 4.x to emit warnings on recent libc. We don't want to check them
as we can't make anything from the result, let's simply surround them
with an empty if statement.
Note that one of the warnings was for chdir("/") which normally cannot
fail since it follows a successful chroot (which means the perms are
necessarily there). Anyway let's move the call uppe to protect it too.
memprintf() is just like snprintf() except that it always returns a properly
sized allocated string that the caller is responsible for freeing. NULL is
returned on serious errors. It also supports stackable calls over the same
pointer since it offers support for automatically freeing a previous one :
memprintf(&err, "invalid argument: '%s'", arg);
...
memprintf(&err, "keyword parser said: <%s>", *err);
...
memprintf(&err, "line parser said: %s\n", *err);
...
free(*err);
The issue only happens when DEBUG_FULL is enabled, which causes
http_msg_analyzer() to complain if it's called twice with an invalid
message, for instance because of two consecutive ACLs using req_proto_http.
The code is commented out when DEBUG_FULL is disabled, so this is not a bug,
just an annoyance for the developer.
The three warnings below are totally wrong since the variables depend on another
one which is only turned on when the variables are initialized. Still this gcc-4.1.2
isn't able to see this and prefers to complain wrongly. So let's initialize the
variables to shut it up since we're not in the fast path.
src/proto_http.c: In function 'acl_fetch_any_cookie_cnt':
src/proto_http.c:8393: warning: 'val_end' may be used uninitialized in this function
src/proto_http.c: In function 'http_process_req_stat_post':
src/proto_http.c:2577: warning: 'st_next_param' may be used uninitialized in this function
src/proto_http.c:2577: warning: 'st_cur_param' may be used uninitialized in this function
It's very annoying that we have to deal with the crappy size_t and with ints
at some places because these ones don't mix well. Patch 6f61b2 changed the
chunk len to int but its size remains size_t and some functions are having
trouble being used by several callers depending on the type of their arguments.
Let's turn extract_cookie_value() to int for now on, and plan a massive cleanup
later to remove all size_t.
- Typo on "dispatch" keyword arguments.
- Reindent some blocks for better parsing by automated tools.
- "option mysql-check" and "option pgsql-check" arguments were not documented
as the others.
I have modified dumpstats.c to show additional information for the show
session <id> command on the statistics socket. This will dump the
public, frontend, backend, and server ip/tcp addresses and port. We
found it useful to have this information available in real time and
could not find another way of getting this information.
The wrong byte was checked for the session_id length in the payload. This
used to work when the session ID was absent because zero was found there,
but when a session ID is present, there is 1/256 chance that the inspected
data contains 0x20 (the actual session ID length), so it fails.
Thanks to Emmanuel Bézagu for reporting this bug.
This bug does not need backporting, it is 1.5 specific.
This patch is a group commit simplify the parsing of the documenation :
- remove remaining tabulations
- realign some lines
- break lines at 80 columns
- add missing chapters in the summary
- fix chapter numbering format
