Commit graph

302 commits

Author SHA1 Message Date
Viktor Szakats
0df6c01db3
tidy-up: rename Curl_safefree()/tool_safefree() to curlx_safefree()
To sync names for the same macro logic between lib and src, and to move
it to the curlx namespace, to match `curlx_free()` that it's calling.

Closes #21151
2026-04-01 19:53:53 +02:00
Stefan Eissing
eb14705280
protocol source, all about protocols and uri schemes
Add protocol.h and protocol.c containing all about libcurl's
known URI schemes and their protocol handlers (so they exist).

Moves the scheme definitions from the various sources files into
protocol.c. Schemes are known and used, even of the protocol
handler is not build or just not implemented at all.

Closes #20906
2026-03-16 08:39:02 +01:00
Viktor Szakats
435eabeac8
badwords: rework exceptions, fix many of them
Also:
- support per-directory and per-upper-directory whitelist entries.
- convert badlist input grep tweak into the above format.
  (except for 'And' which had just a few hits.)
- fix many code exceptions, but do not enforce.
  (there also remain about 350 'will' uses in lib)
- fix badwords in example code, drop exceptions.
- badwords-all: convert to Perl.
  To make it usable from CMake.
- FAQ: reword to not use 'will'. Drop exception.

Closes #20886
2026-03-12 01:01:16 +01:00
Stefan Eissing
da7bfb89a1
connection_check, simplified
The protocol handler method `connection_check` allowed to variable
operations to trigger with variable result bits. Only the `CONNCHECK_ISDEAD`
and `CONNRESULT_DEAD` were in use. Transform the function into
`connection_is_dead` without extra parameter and a bool result.

- Remove defines for `CONNCHECK_*` and `CONNRESULT_*`
- Rename protocol function in handler comments
- Change RTSP implementation (only protocol that uses this)

Closes #20890
2026-03-11 23:28:50 +01:00
Daniel Stenberg
1495489c41
docs: drop basically
Another filler word

Closes #20835
2026-03-07 10:58:36 +01:00
Daniel Stenberg
b4dba346cd
stop using the word 'just'
Everywhere. In documentation and code comments.

It is almost never a good word and almost always a filler that should be
avoided.

Closes #20793
2026-03-03 15:30:22 +01:00
Viktor Szakats
f76a54f890
clang-tidy: add missing and delete redundant parentheses
Reported by clang-tidy v22.1.0.

Ref: https://releases.llvm.org/22.1.0/tools/clang/tools/extra/docs/ReleaseNotes.html

Closes #20749
2026-02-27 01:03:41 +01:00
Viktor Szakats
453470fab1
spacecheck: double spaces in folded strings, fix fallouts
Closes #20695
2026-02-24 00:48:12 +01:00
Daniel Stenberg
207ab758f5
ws/tftp: include header file even when protocol disabled
As the scheme details are still needed. clang 21 warned for this in HTTP-only
builds.

Reported-by: Marcel Raad
URL: https://curl.se/mail/lib-2026-02/0008.html
Closes #20568
2026-02-12 22:47:53 +01:00
Viktor Szakats
9630593650
build: use more const
Mostly with `char *` types.

Also:
- mime, x509asn1, tool_operate, lib3207: drop redundant casts.
- examples/smooth-gtk-thread: add missing variable declaration.
- reduce variable scopes.
- tests/server: move `data_to_hex()` to its only user: `sws`.

Closes #20489
2026-02-02 12:32:49 +01:00
Viktor Szakats
61093e2a81
build: fully omit verbose strings and code when disabled
When the compiler supports C99.

- map logging functions to macro stubs when verbose logging is disabled
  and the compiler is C99. Make sure these stubs silence unused variable
  warnings for non-variadic arguments.
  Before this patch they mapped to function stubs, the same codepath
  used for C89 compiler in this configuration.

- introduce new macros to tell the compiler which code to include
  when verbose code is active, or inactive:

  - `CURLVERBOSE`: defined when verbose code is active.
    To enclose blocks of code only used for verbose logging.

  - `VERBOSE(statement);`:
    compile statement when verbose code is active.
    To mark code lines only used for verbose logging.

  - `NOVERBOSE(statement);`:
    compile statement when verbose code is inactive.
    To suppress warnings for arguments passed to logging functions via
    printf masks, e.g. `NOVERBOSE((void)ipaddress);`, yet keeping
    the warning in verbose builds.

  Note these macros are not the same as `CURL_DISABLE_VERBOSE_STRINGS`.
  Verbose code is always active in C89 mode (without variadic macro
  support).

- drop existing uses of `CURL_DISABLE_VERBOSE_STRINGS` where redundant,
  or replace with the above macros. Ending up reducing the number of
  `#ifdef`s, and also the number of lines.

Assisted-by: Daniel Stenberg
Assisted-by: Jay Satiro
Reported-by: Dan Fandrich
Fixes #20341
Refs: #12105 #12167

Closes #20353
2026-01-21 13:18:35 +01:00
Stefan Eissing
8ce16e7bf2
timeout handling: auto-detect effective timeout
When checking a transfer for being expired via `Curl_timeleft_ms()`,
eleminate the `bool connecting` parameter and have the function check
the `mstate` of the transfer instead.

Advantages:
* eleminate the caller needing awareness if the transfer is
  connecting or in a later state
* fix pingpong timeout handling to check the correct timeout
  during "proto_connect" phases
* avoid using "connecting" timeouts during establishing a secondary
  connection (e.g. FTP) since this would use the timestamp from
  the original, primary connect and thus be wrong

Reported-by: Wyuer on github
Fixes #20347
Closes #20354
2026-01-20 16:43:45 +01:00
Daniel Stenberg
8edc0338f3
lib: separate scheme info from protocol implementation
This allows builds know about all schemes - but only have the protocol
implementations for those actually built-in.

It further allows multiple protocols to reuse the same protocol setup
and functions for both TLS and non-TLS implementations instead of
needing two (or more) structs.

The scheme information is now in 'struct Curl_scheme' and all the
function pointers for each scheme/protocol implementation are in struct
Curl_protocol.

The URL API now always work with all known protocols.

Closes #20351
2026-01-19 23:15:13 +01:00
Viktor Szakats
4651d4c76b
badwords: catch and fix more variants of NN-bit
Closes #20304
2026-01-14 02:35:00 +01:00
Daniel Stenberg
db86f2de9b
tftp: correct the filename length check
Reported-by: z2_
Bug: https://hackerone.com/reports/3508321
Closes #20283
2026-01-13 11:16:47 +01:00
Viktor Szakats
07926b5982
lib: reorder protocol functions to avoid forward declarations (misc)
For protocols: dict, file, gopher, tftp, http, mqtt, smb.

Move protocol hander table to the end of sources, rearrange static
functions is reverse dependency order as necessary.

Closes #20274
2026-01-13 01:31:27 +01:00
Viktor Szakats
7032982896
tidy-up: miscellaneous
- asyn-thrdd.c: scope an include.
- apply more clang-format suggestions.
- tidy-up PP guard comments.
- delete empty line from the top of headers.
- add empty line after `curl_setup.h` include where missing.
- fix indent.
- CODE_STYLE.md: add `strcpy`.
  Follow-up to 8636ad55df #20088
- lib1901.c: drop unnecessary line.
  Follow-up to 436e67f65b #20076

Closes #20070
2025-12-26 22:06:09 +01:00
Daniel Stenberg
a535be4ea0
curlx: curlx_strcopy() instead of strcpy()
This function REQUIRES the size of the target buffer as well as the
length of the source string. Meant to make it harder to do a bad
strcpy().

Removes 23 calls to strcpy().

Closes #20067
2025-12-22 23:01:05 +01:00
Viktor Szakats
e8415a8296
lib: drop, or replace sendf.h with curl_trc.h where possible
- replace `sendf.h` with `curl_trc.h` where it was included just for it.
- drop unused `curl_trc.h` includes.
- easy: delete obsolete comment about `send.h` include reason.

Also:
- move out `curl_trc.h` include from `sendf.h` and include it directly
  in users, where not done already. To flatten the include tree and
  to less rely on indirect includes.
- stop including `sendf.h` from other headers, replace it with forward
  declaration of `Curl_easy`, as done already elsewhere.

Verified with an all non-unity CI run.

Closes #20061
2025-12-21 12:39:25 +01:00
Viktor Szakats
d11b8593a2
build: drop duplicate include curl/curl.h and others
- curl_range: replace `sendf.h` with direct header dependency
  `curl_trc.h`.
- drop `curl/curl.h` includes from internal sourcees in favor of the
  include made from `curl_setup.h`. Replace it with the latter where
  it's the only include.
- include `curl_setup.h` before using macros, where missing.
- drop redundant `stdlib.h`, `string.h` includes, in favor of
  `curl_setup_once.h` including them.
- drop redundant `limits.h` in favor of `curl_setup.h` including it.
- fake_addrinfo.h: fix typo in comment.
- curl_setup_once.h: drop `stdio.h` in favor of earlier include in
  `curl_setup.h`.
- drop stray, unused, `stddef.h` includes.
- memdebug.h: add missing `stddef.h` include. (relying on accidental
  includes via other headers before this patch.)
- stddef.h: document why it's included.
- strerr: drop `curl/mprintf.h` in favor of `curl/curl.h` including it
  via `curl_setup.h`.

Closes #20027
2025-12-19 10:58:11 +01:00
Viktor Szakats
fb50214604
build: drop unused multiif.h includes
Closes #20023
2025-12-19 01:45:05 +01:00
Viktor Szakats
308c347c8b
tidy-up: miscellaneous
- apply more clang-format.
- lib/version: use `CURL_ARRAYSIZE()`.
- INSTALL-CMAKE.md: sync-up an option description with others.
- examples: delete unused main args.
- examples/ftpgetinfo: document `_CRT_SECURE_NO_WARNINGS` symbol.
- delete remaining stray duplicate lines.
- acinclude.m4: drop an unnecessary x-hack.
- vtls/mbedtls: join a URL split into two lines.
- src/tool_cb_see: add parentheses around macro expressions.
- src/tool_operate: move literals to the right side of comparisons.
- libtests: sync up fopen/fstat error messages between tests.
- curl_setup.h: replace `if ! defined __LP64` with `ifndef __LP64`.
  I assume it makes no difference on Tandem systems, as the latter form
  is already used in `include/curl/system.h`.

Closes #20018
2025-12-18 21:27:58 +01:00
Stefan Eissing
2de22a00c7
lib: keep timestamp in easy handle
Use `data->progress.now` as the timestamp of proecssing a transfer.
Update it on significant events and refrain from calling `curlx_now()`
in many places.

The problem this addresses is
a) calling curlx_now() has costs, depending on platform. Calling it
   every time results in 25% increase `./runtest` duration on macOS.
b) we used to pass a `struct curltime *` around to save on calls, but
   when some method directly use `curx_now()` and some use the passed
   pointer, the transfer experienes non-linear time. This results in
   timeline checks to report events in the wrong order.

By keeping a timestamp in the easy handle and updating it there, no
longer invoking `curlx_now()` in the "lower" methods, the transfer
can observer a steady clock progression.

Add documentation in docs/internals/TIME-KEEPING.md

Reported-by: Viktor Szakats
Fixes #19935
Closes #19961
2025-12-16 08:48:44 +01:00
Viktor Szakats
c3b030b860
lib: fix formatting nits (part 3)
From `lib/h` to `lib/w`.

part 1: 47a1ab2ebe #19764
part 2: 86b346443b #19800

Closes #19811
2025-12-03 14:50:16 +01:00
Viktor Szakats
193cb00ce9
build: stop overriding standard memory allocation functions
Before this patch curl used the C preprocessor to override standard
memory allocation symbols: malloc, calloc, strdup, realloc, free.
The goal of these is to replace them with curl's debug wrappers in
`CURLDEBUG` builds, another was to replace them with the wrappers
calling user-defined allocators in libcurl. This solution needed a bunch
of workarounds to avoid breaking external headers: it relied on include
order to do the overriding last. For "unity" builds it needed to reset
overrides before external includes. Also in test apps, which are always
built as single source files. It also needed the `(symbol)` trick
to avoid overrides in some places. This would still not fix cases where
the standard symbols were macros. It was also fragile and difficult
to figure out which was the actual function behind an alloc or free call
in a specific piece of code. This in turn caused bugs where the wrong
allocator was accidentally called.

To avoid these problems, this patch replaces this solution with
`curlx_`-prefixed allocator macros, and mapping them _once_ to either
the libcurl wrappers, the debug wrappers or the standard ones, matching
the rest of the code in libtests.

This concludes the long journey to avoid redefining standard functions
in the curl codebase.

Note: I did not update `packages/OS400/*.c` sources. They did not
`#include` `curl_setup.h`, `curl_memory.h` or `memdebug.h`, meaning
the overrides were never applied to them. This may or may not have been
correct. For now I suppressed the direct use of standard allocators
via a local `.checksrc`. Probably they (except for `curlcl.c`) should be
updated to include `curl_setup.h` and use the `curlx_` macros.

This patch changes mappings in two places:
- `lib/curl_threads.c` in libtests: Before this patch it mapped to
  libcurl allocators. After, it maps to standard allocators, like
  the rest of libtests code.
- `units`: before this patch it mapped to standard allocators. After, it
  maps to libcurl allocators.

Also:
- drop all position-dependent `curl_memory.h` and `memdebug.h` includes,
  and delete the now unnecessary headers.
- rename `Curl_tcsdup` macro to `curlx_tcsdup` and define like the other
  allocators.
- map `curlx_strdup()` to `_strdup()` on Windows (was: `strdup()`).
  To fix warnings silenced via `_CRT_NONSTDC_NO_DEPRECATE`.
- multibyte: map `curlx_convert_*()` to `_strdup()` on Windows
  (was: `strdup()`).
- src: do not reuse the `strdup` name for the local replacement.
- lib509: call `_strdup()` on Windows (was: `strdup()`).
- test1132: delete test obsoleted by this patch.
- CHECKSRC.md: update text for `SNPRINTF`.
- checksrc: ban standard allocator symbols.

Follow-up to b12da22db1 #18866
Follow-up to db98daab05 #18844
Follow-up to 4deea9396b #18814
Follow-up to 9678ff5b1b #18776
Follow-up to 10bac43b87 #18774
Follow-up to 20142f5d06 #18634
Follow-up to bf7375ecc5 #18503
Follow-up to 9863599d69 #18502
Follow-up to 3bb5e58c10 #17827

Closes #19626
2025-11-28 10:44:26 +01:00
Stefan Eissing
24b36fdd15
ratelimit: redesign
Description of how this works in `docs/internal/RATELIMITS.ms`.

Notable implementation changes:
- KEEP_SEND_PAUSE/KEEP_SEND_HOLD and KEEP_RECV_PAUSE/KEEP_RECV_HOLD
  no longer exist. Pausing is down via blocked the new rlimits.
- KEEP_SEND_TIMED no longer exists. Pausing "100-continue" transfers
  is done in the new `Curl_http_perform_pollset()` method.
- HTTP/2 rate limiting implemented via window updates. When
  transfer initiaiting connection has a ratelimit, adjust the
  initial window size
- HTTP/3 ngtcp2 rate limitin implemnented via ack updates
- HTTP/3 quiche does not seem to support this via its API
- the default progress-meter has been improved for accuracy
  in "current speed" results.

pytest speed tests have been improved.

Closes #19384
2025-11-24 23:34:05 +01:00
Viktor Szakats
1b48c6148a
tidy-up: miscellaneous
- schannel: delete superfluous parenthesis.
- tftp: delete stray space from log output.
- ws: update guard comment.
- docs/examples: constify variables.
- runtests/servers: enclose unknown parameter between quotes.
- scripts/perlcheck.sh: drop redundant grep `-E` option.
- THANKS: move names from comments to THANKS.
- sync `--depth` option style across scripts.
- sync git repo URL ending between some scripts.
- BINDINGS.md: drop protocol from archive.org URL path.
- whitespace, indent, unfold lines.

Closes #19565
2025-11-17 13:32:43 +01:00
Stefan Eissing
78a610cb83
lib: rename curlx_timediff to curlx_timeleft_ms
Rename `Curl_timeleft()` to `Curl_timeleft_ms()` to make the units in
the returned `timediff_t` clear. (We used to always have ms there, but
with QUIC started to sometimes calc ns as well).

Rename some assigned vars without `_ms` suffix for clarity as well.

Closes #19486
2025-11-13 13:12:58 +01:00
x2018
59584399a5
tftp: release filename if conn_get_remote_addr fails
Closes #19409
2025-11-09 11:32:57 +01:00
x2018
dd71f61ea2
lib: cleanup for some typos about spaces and code style
Closes #19370
2025-11-05 14:07:28 +01:00
Daniel Stenberg
be852e39b2
tftp: check for trailing ";mode=" in URL without strstr
RFC 3617 defines two specific modes, "netascii" and "octet". This code
now checks only for those trailing ones - and not in the hostname since
they can't be there anymore.

Assisted-by: Jay Satiro
Closes #19070
2025-10-15 09:59:57 +02:00
Daniel Stenberg
e90b2aaa7e
tftp: error requests for blank filenames
Reported-by: Joshua Rogers
Closes #19033
2025-10-12 15:37:07 +02:00
Daniel Stenberg
3660e6da80
tftp: return error if it hits an illegal state
Reported-by: Joshua Rogers
Closes #18894
2025-10-06 23:52:57 +02:00
Daniel Stenberg
bc90f80556
tftp: default timeout per block is now 15 seconds
Down from the previous (rather ridiculous) 3600.

Reported-by: Joshua Rogers
Closes #18893
2025-10-06 23:51:43 +02:00
Daniel Stenberg
f1ed50a517
tftp: don't pin or check address if recvfrom returns error
Follow-up to c4f9977c66
Reported-by: Joshua Rogers
Closes #18892
2025-10-06 23:50:34 +02:00
Viktor Szakats
b12da22db1
lib: stop overriding system printf symbols
After this patch, the codebase no longer overrides system printf
functions. Instead it explicitly calls either the curl printf functions
`curl_m*printf()` or the system ones using their original names.

Also:
- drop unused `curl_printf.h` includes.
- checksrc: ban system printf functions, allow where necessary.

Follow-up to db98daab05 #18844
Follow-up to 4deea9396b #18814

Closes #18866
2025-10-06 20:57:59 +02:00
Viktor Szakats
34ad78da89
curlx: move Curl_strerror, use in src and tests, ban strerror globally
Also:
- tests/server: replace local `sstrerror()` with `curlx_strerror()`.
- tests/server: show the error code next to the string, where missing.
- curlx: use `curl_msnprintf()` when building for src and tests.
  (units was already using it.)
- lib: drop unused includes found along the way.
- curlx_strerror(): avoid compiler warning (and another similar one):
  ```
  In file included from servers.c:14:
  ../../lib/../../lib/curlx/strerr.c: In function ‘curlx_strerror’:
  ../../lib/../../lib/curlx/strerr.c:328:32: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
    328 |       SNPRINTF(buf, buflen, "%s", msg);
        |                                ^
  ../../lib/../../lib/curlx/strerr.c:47:18: note: ‘snprintf’ output 1 or more bytes (assuming 2) into a destination of size 1
     47 | #define SNPRINTF snprintf
        |                  ^
  ../../lib/../../lib/curlx/strerr.c:328:7: note: in expansion of macro ‘SNPRINTF’
    328 |       SNPRINTF(buf, buflen, "%s", msg);
        |       ^~~~~~~~
  ```

Follow-up to 45438c8d6f #18823

Closes #18840
2025-10-06 09:44:23 +02:00
Daniel Stenberg
9f75603d4f
tftp: only check address if it was stored
If recvfrom() fails, it might not have stored an address.

Follow-up to c4f9977c66

Pointed out by CodeSonar

Closes #18738
2025-09-25 16:54:19 +02:00
Daniel Stenberg
c4f9977c66
tftp: pin the first used address
Store the used remote address on the first receive call and then make
sure that it remains the same address on subsequent calls to reduce the
risk of tampering. Doesn't make the transfer secure because it is still
unauthenticated and clear text.

Reported in Joshua's sarif data

Closes #18658
2025-09-21 23:01:01 +02:00
Daniel Stenberg
66d6075af9
tftp: return error when sendto() fails
The code just called failf() and then continued without returning error.

Reported in Joshua's sarif data

Closes #18643
2025-09-20 22:35:12 +02:00
Daniel Stenberg
ca8ec6e033
tftp: handle tftp_multi_statemach() return code
Previously just ignored.

Reported in Joshua's sarif data

Closes #18638
2025-09-20 17:25:35 +02:00
Daniel Stenberg
54aff4db3c
tftp: check and act on tftp_set_timeouts() returning error
Reported-by: Joshua Rogers
Ref: https://github.com/curl/curl/pull/18574#issuecomment-3300183302
Closes #18603
2025-09-18 17:54:13 +02:00
Joshua Rogers
ad147ec53d
tftp: propagate expired timer from tftp_state_timeout()
When Curl_timeleft() < 0 we used to return 0, masking the expiry and
skipping the caller’s (timeout_ms < 0) path. Now we set FIN and return
the negative value so tftp_multi_statemach() aborts with
CURLE_OPERATION_TIMEDOUT as intended.

Closes #18574
2025-09-18 17:34:31 +02:00
Viktor Szakats
49145249be
tidy-up: drop stray "unused" comments
Closes #18453
2025-09-03 16:31:16 +02:00
Stefan Eissing
5b80b4c012
lib: replace getsock() logic with pollsets
`getsock()` calls operated on a global limit that could
not be configure beyond 16 sockets. This is no longer adequate
with the new happy eyeballing strategy.

Instead, do the following:
- make `struct easy_pollset` dynamic. Starting with
  a minimal room for two sockets, the very common case,
  allow it to grow on demand.
- replace all protocol handler getsock() calls with pollsets
  and a CURLcode to return failures
- add CURLcode return for all connection filter `adjust_pollset()`
  callbacks, since they too can now fail.
- use appropriately in multi.c and multi_ev.c
- fix unit2600 to trigger pollset growth

Closes #18164
2025-08-04 23:43:13 +02:00
Stefan Eissing
e9ae1bd404
connection: clarify transport
The `transport` to use for a transfer, e.g. TCP/QUIC/UNIX/UDP, is
initially selected by options and protocol used. This is set at the
`struct connectdata` as `transport` member.

During connection establishment, this transport may change due to
Alt-Svc or Happy-Eyeballing. Most common is the switch from TCP to QUIC.

Rename the connection member to `transport_wanted` and add a way to
query the connection for the transport in use via a new connection
filter query.

The filter query can also be used in the happy eyeballing attempts when
code needs to know which transport is used by the "filter below". This
happens in wolfssl initialization, as one example.

Closes #17923
2025-07-14 14:33:18 +02:00
Stefan Eissing
63381421f5
connection: eliminate member remote_addr
Used to be a pointer set (and cleared) by the socket connection filters
to a struct in their contexts. Instead, add a filter query method to
obtain the pointer when needed.

Closes #17385
2025-06-20 12:54:36 +02:00
Daniel Stenberg
255aac56f9
curlx: move into to curlx/
Move curlx_ functions into its own subdir.

The idea is to use the curlx_ prefix proper on these functions, and use
these same function names both in tool, lib and test suite source code.
Stop the previous special #define setup for curlx_ names.

The printf defines are now done for the library alone. Tests no longer
use the printf defines. The tool code sets its own defines. The printf
functions are not curlx, they are publicly available.

The strcase defines are not curlx_ functions and should not be used by
tool or server code.

dynbuf, warnless, base64, strparse, timeval, timediff are now proper
curlx functions.

When libcurl is built statically, the functions from the library can be
used as-is. The key is then that the functions must work as-is, without
having to be recompiled for use in tool/tests. This avoids symbol
collisions - when libcurl is built statically, we use those functions
directly when building the tool/tests. When libcurl is shared, we
build/link them separately for the tool/tests.

Assisted-by: Jay Satiro

Closes #17253
2025-05-07 11:01:15 +02:00
Stefan Eissing
378aa011e6
tftp: use connections meta hash
Use connection meta hash for state struct instead of union pointer at
connectdata.

Closes #17235
2025-05-06 09:05:27 +02:00
Viktor Szakats
f4e23950c7
build: enable -Wcast-qual, fix or silence compiler warnings
The issues found fell into these categories, with the applied fixes:

- const was accidentally stripped.
  Adjust code to not cast or cast with const.

- const/volatile missing from arguments, local variables.
  Constify arguments or variables, adjust/delete casts. Small code
  changes in a few places.

- const must be stripped because an API dependency requires it.
  Strip `const` with `CURL_UNCONST()` macro to silence the warning out
  of our control. These happen at API boundaries. Sometimes they depend
  on dependency version, which this patch handles as necessary. Also
  enable const support for the zlib API, using `ZLIB_CONST`. Supported
  by zlib 1.2.5.2 and newer.

- const must be stripped because a curl API requires it.
  Strip `const` with `CURL_UNCONST()` macro to silence the warning out
  of our immediate control. For example we promise to send a non-const
  argument to a callback, though the data is const internally.

- other cases where we may avoid const stripping by code changes.
  Also silenced with `CURL_UNCONST()`.

- there are 3 places where `CURL_UNCONST()` is cast again to const.
  To silence this type of warning:
  ```
  lib/vquic/curl_osslq.c:1015:29: error: to be safe all intermediate
    pointers in cast from 'unsigned char **' to 'const unsigned char **'
    must be 'const' qualified [-Werror=cast-qual]
  lib/cf-socket.c:734:32: error: to be safe all intermediate pointers in
    cast from 'char **' to 'const char **' must be 'const' qualified
    [-Werror=cast-qual]
  ```
  There may be a better solution, but I couldn't find it.

These cases are handled in separate subcommits, but without further
markup.

If you see a `-Wcast-qual` warning in curl, we appreciate your report
about it.

Closes #16142
2025-03-10 22:30:15 +01:00