lib/src: white space edits to comply better with code style

... as checksrc now finds and complains about these.

Closes #14921

http2: fix GOAWAY message sent to server

- fix typo in GOAWAY debug message "shutown" -> "shutdown"

Closes https://github.com/curl/curl/pull/14623

http2: improved upload eos handling

- replace the counting of upload lengths with the new eos send flag
- improve frequency of stream draining to happen less on events where it
is

http2: improved upload eos handling

- replace the counting of upload lengths with the new eos send flag
- improve frequency of stream draining to happen less on events where it
is not needed
- this PR is based on #14220

http2, cf-h2-proxy: fix EAGAINed out buffer
- in adjust pollset and shutdown handling, a non-empty `ctx->outbufq`
must trigger send polling, irregardless of http/2 flow control
- in http2, fix retry handling of blocked GOAWAY frame

test case improvement:
- let client 'upload-pausing' handle http versions

Closes #14253

show more ...

cfilters: send flush

Since data can be held in connection filter buffers when sending gives
EAGAIN, add methods to query this and perform flushing of those buffers.

The transfer

cfilters: send flush

Since data can be held in connection filter buffers when sending gives
EAGAIN, add methods to query this and perform flushing of those buffers.

The transfer loop will continue sending until all upload data is
processed and the connection is flushed.

- add `CF_QUERY_SEND_PENDING` to query filters
- add `CF_CTRL_DATA_SEND_FLUSH` to flush filters
- change `Curl_req_want_send()` to query the connection
if it needs flushing
- use `Curl_req_want_send()` to determine the POLLOUT
in the PERFORMING multi state
- implement flush handling in the HTTP/2 connection filter

Closes #14271

show more ...

lib: add eos flag to send methods

Adds a `bool eos` flag to send methods to indicate that the data
is the last chunk the invovled transfer wants to send to the server.

This will

lib: add eos flag to send methods

Adds a `bool eos` flag to send methods to indicate that the data
is the last chunk the invovled transfer wants to send to the server.

This will help protocol filters like HTTP/2 and 3 to forward the
stream's EOF flag and also allow to EAGAIN such calls when buffers
are not yet fully flushed.

Closes #14220

show more ...

Revert "lib: send eos flag"

This reverts commit be93299f10ef0b2bf7fe5c82140120073831867a.

lib: send eos flag

Adds a `bool eos` flag to send methods to indicate that the data is the
last chunk the invovled transfer wants to send to the server.

This will help protocol

lib: send eos flag

Adds a `bool eos` flag to send methods to indicate that the data is the
last chunk the invovled transfer wants to send to the server.

This will help protocol filters like HTTP/2 and 3 to forward the
stream's EOF flag and also allow to EAGAIN such calls when buffers are
not yet fully flushed.

Closes #14220

show more ...

multi: fix pollset during RESOLVING phase

- add a DEBUGASSERT for when a transfer's pollset should not be empty.
- move write unpausing from transfer loop into curl_easy_pause. This

multi: fix pollset during RESOLVING phase

- add a DEBUGASSERT for when a transfer's pollset should not be empty.
- move write unpausing from transfer loop into curl_easy_pause. This
make sure that the url_updatesocket() finds the correct state when
updating socket events.
- fix HTTP/2 proxy during connect phase to set sockets correctly
- fix test2600 to simulate a socket set
- move write unpausing from transfer loop into curl_easy_pause. This
make sure that the url_updatesocket() finds the correct state when
updating socket events.
- waiting for the resolver to deliver might not involve any sockets to
wait for. Do not generate a warning.

Fixes #14047
Closes #14074

show more ...

code: language cleanup in comments

Based on the standards and guidelines we use for our documentation.

- expand contractions (they're => they are etc)
- host name = > hostname

code: language cleanup in comments

Based on the standards and guidelines we use for our documentation.

- expand contractions (they're => they are etc)
- host name = > hostname
- file name => filename
- user name = username
- man page => manpage
- run-time => runtime
- set-up => setup
- back-end => backend
- a HTTP => an HTTP
- Two spaces after a period => one space after period

Closes #14073

show more ...

lib: graceful connection shutdown

When libcurl discards a connection there are two phases this may go
through: "shutdown" and "closing". If a connection is aborted, the
shutdown phas

lib: graceful connection shutdown

When libcurl discards a connection there are two phases this may go
through: "shutdown" and "closing". If a connection is aborted, the
shutdown phase is skipped and it is closed right away.

The connection filters attached to the connection implement the phases
in their `do_shutdown()` and `do_close()` callbacks. Filters carry now a
`shutdown` flags next to `connected` to keep track of the shutdown
operation.

Filters are shut down from top to bottom. If a filter is not connected,
its shutdown is skipped. Notable filters that *do* something during
shutdown are HTTP/2 and TLS. HTTP/2 sends the GOAWAY frame. TLS sends
its close notify and expects to receive a close notify from the server.

As sends and receives may EAGAIN on the network, a shutdown is often not
successful right away and needs to poll the connection's socket(s). To
facilitate this, such connections are placed on a new shutdown list
inside the connection cache.

Since managing this list requires the cooperation of a multi handle,
only the connection cache belonging to a multi handle is used. If a
connection was in another cache when being discarded, it is removed
there and added to the multi's cache. If no multi handle is available at
that time, the connection is shutdown and closed in a one-time,
best-effort attempt.

When a multi handle is destroyed, all connection still on the shutdown
list are discarded with a final shutdown attempt and close. In curl
debug builds, the environment variable `CURL_GRACEFUL_SHUTDOWN` can be
set to make this graceful with a timeout in milliseconds given by the
variable.

The shutdown list is limited to the max number of connections configured
for a multi cache. Set via CURLMOPT_MAX_TOTAL_CONNECTIONS. When the
limit is reached, the oldest connection on the shutdown list is
discarded.

- In multi_wait() and multi_waitfds(), collect all connection caches
involved (each transfer might carry its own) into a temporary list.
Let each connection cache on the list contribute sockets and
POLLIN/OUT events it's connections are waiting for.

- in multi_perform() collect the connection caches the same way and let
them peform their maintenance. This will make another non-blocking
attempt to shutdown all connections on its shutdown list.

- for event based multis (multi->socket_cb set), add the sockets and
their poll events via the callback. When `multi_socket()` is invoked
for a socket not known by an active transfer, forward this to the
multi's cache for processing. On closing a connection, remove its
socket(s) via the callback.

TLS connection filters MUST NOT send close nofity messages in their
`do_close()` implementation. The reason is that a TLS close notify
signals a success. When a connection is aborted and skips its shutdown
phase, the server needs to see a missing close notify to detect
something has gone wrong.

A graceful shutdown of FTP's data connection is performed implicitly
before regarding the upload/download as complete and continuing on the
control connection. For FTP without TLS, there is just the socket close
happening. But with TLS, the sent/received close notify signals that the
transfer is complete and healthy. Servers like `vsftpd` verify that and
reject uploads without a TLS close notify.

- added test_19_* for shutdown related tests
- test_19_01 and test_19_02 test for TCP RST packets
which happen without a graceful shutdown and should
no longer appear otherwise.
- add test_19_03 for handling shutdowns by the server
- add test_19_04 for handling shutdowns by curl
- add test_19_05 for event based shutdowny by server
- add test_30_06/07 and test_31_06/07 for shutdown checks
on FTP up- and downloads.

Closes #13976

show more ...

connection: shutdown TLS (for FTP) better

This adds connection shutdown infrastructure and first use for FTP. FTP
data connections, when not encountering an error, are now shut down in a

connection: shutdown TLS (for FTP) better

This adds connection shutdown infrastructure and first use for FTP. FTP
data connections, when not encountering an error, are now shut down in a
blocking way with a 2sec timeout.

- add cfilter `Curl_cft_shutdown` callback
- keep a shutdown start timestamp and timeout at connectdata
- provide shutdown timeout default and member in
`data->set.shutdowntimeout`.
- provide methods for starting, interrogating and clearing
shutdown timers
- provide `Curl_conn_shutdown_blocking()` to shutdown the
`sockindex` filter chain in a blocking way. Use that in FTP.
- add `Curl_conn_cf_poll()` to wait for socket events during
shutdown of a connection filter chain.
This gets the monitoring sockets and events via the filters
"adjust_pollset()" methods. This gives correct behaviour when
shutting down a TLS connection through a HTTP/2 proxy.
- Implement shutdown for all socket filters
- for HTTP/2 and h2 proxying to send GOAWAY
- for TLS backends to the best of their capabilities
- for tcp socket filter to make a final, nonblocking
receive to avoid unwanted RST states
- add shutdown forwarding to happy eyeballers and
https connect ballers when applicable.

Closes #13904

show more ...

lib: tidy up types and casts

Cherry-picked from #13489
Closes #13862

tls: use shared init code for TCP+QUIC

Closes #13172

http: revisit http_perhapsrewind()

- use facilities provided by client readers better
- work also for non-uploading requests like GET/HEAD
- update documentation

Closes #131

http: revisit http_perhapsrewind()

- use facilities provided by client readers better
- work also for non-uploading requests like GET/HEAD
- update documentation

Closes #13117

show more ...

build: enable missing OpenSSF-recommended warnings, with fixes

https://best.openssf.org/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.html
as of 2023-11-29 [1]

build: enable missing OpenSSF-recommended warnings, with fixes

https://best.openssf.org/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C++.html
as of 2023-11-29 [1].

Enable new recommended warnings (except `-Wsign-conversion`):

- enable `-Wformat=2` for clang (in both cmake and autotools).
- add `CURL_PRINTF()` internal attribute and mark functions accepting
printf arguments with it. This is a copy of existing
`CURL_TEMP_PRINTF()` but using `__printf__` to make it compatible
with redefinting the `printf` symbol:
https://gcc.gnu.org/onlinedocs/gcc-3.0.4/gcc_5.html#SEC94
- fix `CURL_PRINTF()` and existing `CURL_TEMP_PRINTF()` for
mingw-w64 and enable it on this platform.
- enable `-Wimplicit-fallthrough`.
- enable `-Wtrampolines`.
- add `-Wsign-conversion` commented with a FIXME.
- cmake: enable `-pedantic-errors` the way we do it with autotools.
Follow-up to d5c0351055d5709da8f3e16c91348092fdb481aa #2747
- lib/curl_trc.h: use `CURL_FORMAT()`, this also fixes it to enable format
checks. Previously it was always disabled due to the internal `printf`
macro.

Fix them:

- fix bug where an `set_ipv6_v6only()` call was missed in builds with
`--disable-verbose` / `CURL_DISABLE_VERBOSE_STRINGS=ON`.
- add internal `FALLTHROUGH()` macro.
- replace obsolete fall-through comments with `FALLTHROUGH()`.
- fix fallthrough markups: Delete redundant ones (showing up as
warnings in most cases). Add missing ones. Fix indentation.
- silence `-Wformat-nonliteral` warnings with llvm/clang.
- fix one `-Wformat-nonliteral` warning.
- fix new `-Wformat` and `-Wformat-security` warnings.
- fix `CURL_FORMAT_SOCKET_T` value for mingw-w64. Also move its
definition to `lib/curl_setup.h` allowing use in `tests/server`.
- lib: fix two wrongly passed string arguments in log outputs.
Co-authored-by: Jay Satiro
- fix new `-Wformat` warnings on mingw-w64.

[1] https://github.com/ossf/wg-best-practices-os-developers/blob/56c0fde3895bfc55c8a973ef49a2572c507b2ae1/docs/Compiler-Hardening-Guides/Compiler-Options-Hardening-Guide-for-C-and-C%2B%2B.md

Closes #12489

show more ...

lib: eliminate `conn->cselect_bits`

- use `data->state.dselect_bits` everywhere instead
- remove `bool *comeback` parameter as non-zero
`data->state.dselect_bits` will indicate tha

lib: eliminate `conn->cselect_bits`

- use `data->state.dselect_bits` everywhere instead
- remove `bool *comeback` parameter as non-zero
`data->state.dselect_bits` will indicate that IO is
incomplete.

Closes #12512

show more ...

misc: fix -Walloc-size warnings

GCC 14 introduces a new -Walloc-size included in -Wextra which gives:

```
src/tool_operate.c: In function ‘add_per_transfer’:
src/tool_operat

misc: fix -Walloc-size warnings

GCC 14 introduces a new -Walloc-size included in -Wextra which gives:

```
src/tool_operate.c: In function ‘add_per_transfer’:
src/tool_operate.c:213:5: warning: allocation of insufficient size ‘1’ for type ‘struct per_transfer’ with size ‘480’ [-Walloc-size]
213 | p = calloc(sizeof(struct per_transfer), 1);
| ^
src/var.c: In function ‘addvariable’:
src/var.c:361:5: warning: allocation of insufficient size ‘1’ for type ‘struct var’ with size ‘32’ [-Walloc-size]
361 | p = calloc(sizeof(struct var), 1);
| ^
```

The calloc prototype is:
```
void *calloc(size_t nmemb, size_t size);
```

So, just swap the number of members and size arguments to match the
prototype, as we're initialising 1 struct of size `sizeof(struct
...)`. GCC then sees we're not doing anything wrong.

Closes #12292

show more ...

lib: introduce struct easy_poll_set for poll information

Connection filter had a `get_select_socks()` method, inspired by the
various `getsocks` functions involved during the lifetime of

lib: introduce struct easy_poll_set for poll information

Connection filter had a `get_select_socks()` method, inspired by the
various `getsocks` functions involved during the lifetime of a
transfer. These, depending on transfer state (CONNECT/DO/DONE/ etc.),
return sockets to monitor and flag if this shall be done for POLLIN
and/or POLLOUT.

Due to this design, sockets and flags could only be added, not
removed. This led to problems in filters like HTTP/2 where flow control
prohibits the sending of data until the peer increases the flow
window. The general transfer loop wants to write, adds POLLOUT, the
socket is writeable but no data can be written.

This leads to cpu busy loops. To prevent that, HTTP/2 did set the
`SEND_HOLD` flag of such a blocked transfer, so the transfer loop cedes
further attempts. This works if only one such filter is involved. If a
HTTP/2 transfer goes through a HTTP/2 proxy, two filters are
setting/clearing this flag and may step on each other's toes.

Connection filters `get_select_socks()` is replaced by
`adjust_pollset()`. They get passed a `struct easy_pollset` that keeps
up to `MAX_SOCKSPEREASYHANDLE` sockets and their `POLLIN|POLLOUT`
flags. This struct is initialized in `multi_getsock()` by calling the
various `getsocks()` implementations based on transfer state, as before.

After protocol handlers/transfer loop have set the sockets and flags
they want, the `easy_pollset` is *always* passed to the filters. Filters
"higher" in the chain are called first, starting at the first
not-yet-connection one. Each filter may add sockets and/or change
flags. When all flags are removed, the socket itself is removed from the
pollset.

Example:

* transfer wants to send, adds POLLOUT
* http/2 filter has a flow control block, removes POLLOUT and adds
POLLIN (it is waiting on a WINDOW_UPDATE from the server)
* TLS filter is connected and changes nothing
* h2-proxy filter also has a flow control block on its tunnel stream,
removes POLLOUT and adds POLLIN also.
* socket filter is connected and changes nothing
* The resulting pollset is then mixed together with all other transfers
and their pollsets, just as before.

Use of `SEND_HOLD` is no longer necessary in the filters.

All filters are adapted for the changed method. The handling in
`multi.c` has been adjusted, but its state handling the the protocol
handlers' `getsocks` method are untouched.

The most affected filters are http/2, ngtcp2, quiche and h2-proxy. TLS
filters needed to be adjusted for the connecting handshake read/write
handling.

No noticeable difference in performance was detected in local scorecard
runs.

Closes #11833

show more ...

http2: header conversion tightening

- fold the code to convert dynhds to the nghttp2 structs
into a dynhds internal method
- saves code duplication
- pacifies compiler analyzer

http2: header conversion tightening

- fold the code to convert dynhds to the nghttp2 structs
into a dynhds internal method
- saves code duplication
- pacifies compiler analyzers

Closes #12097

show more ...

spelling: fix codespell 2.2.6 typos

Closes #12019

openssl: improve ssl shutdown handling

- If SSL shutdown is not finished then make an additional call to
SSL_read to gather additional tracing.

- Fix http2 and h2-proxy filter

openssl: improve ssl shutdown handling

- If SSL shutdown is not finished then make an additional call to
SSL_read to gather additional tracing.

- Fix http2 and h2-proxy filters to forward do_close() calls to the next
filter.

For example h2 and SSL shutdown before and after this change:

Before:

Curl_conn_close -> cf_hc_close -> Curl_conn_cf_discard_chain ->
ssl_cf_destroy

After:

Curl_conn_close -> cf_hc_close -> cf_h2_close -> cf_setup_close ->
ssl_cf_close

Note that currently the tracing does not show output on the connection
closure handle. Refer to discussion in #11878.

Ref: https://github.com/curl/curl/discussions/11878

Closes https://github.com/curl/curl/pull/11858

show more ...

http: h1/h2 proxy unification

- use shared code for setting up the CONNECT request
when tunneling, used in HTTP/1.x and HTTP/2 proxying
- eliminate use of Curl_buffer_send() and ot

http: h1/h2 proxy unification

- use shared code for setting up the CONNECT request
when tunneling, used in HTTP/1.x and HTTP/2 proxying
- eliminate use of Curl_buffer_send() and other manipulations
of `data->req` or `data->state.ulbuf`

Closes #11808

show more ...

cmake: fix unity symbol collisions in h2 builds

Regression from 331b89a319d0067fa1e6441719307cfef9c7960f

Reviewed-by: Daniel Stenberg
Reviewed-by: Jay Satiro
Closes #11912

h2-proxy: remove left-over mistake in drain_tunnel()

Left-over from 331b89a319

Reported-by: 南宫雪珊

Closes https://github.com/curl/curl/pull/11877

http2: polish things around POST

- added test cases for various code paths
- fixed handling of blocked write when stream had
been closed inbetween attempts
- re-enabled DEBUGAS

http2: polish things around POST

- added test cases for various code paths
- fixed handling of blocked write when stream had
been closed inbetween attempts
- re-enabled DEBUGASSERT on send with smaller data size

- in debug builds, environment variables can be set to simulate a slow
network when sending data. cf-socket.c and vquic.c support
* CURL_DBG_SOCK_WBLOCK: percentage of send() calls that should be
answered with a EAGAIN. TCP/UNIX sockets.
This is chosen randomly.
* CURL_DBG_SOCK_WPARTIAL: percentage of data that shall be written
to the network. TCP/UNIX sockets.
Example: 80 means a send with 1000 bytes would only send 800
This is applied to every send.
* CURL_DBG_QUIC_WBLOCK: percentage of send() calls that should be
answered with EAGAIN. QUIC only.
This is chosen randomly.

Closes #11756

show more ...