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

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lib: rename Curl_strndup to Curl_memdup0 to avoid misunderstanding

Since the copy does not stop at a null byte, let's not call it anything
that makes you think it works like the common s

lib: rename Curl_strndup to Curl_memdup0 to avoid misunderstanding

Since the copy does not stop at a null byte, let's not call it anything
that makes you think it works like the common strndup() function.

Based on feedback from Jay Satiro, Stefan Eissing and Patrick Monnerat

Closes #12490

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lib: strndup/memdup instead of malloc, memcpy and null-terminate

- bufref: use strndup
- cookie: use strndup
- formdata: use strndup
- ftp: use strndup
- gtls: use aprin

lib: strndup/memdup instead of malloc, memcpy and null-terminate

- bufref: use strndup
- cookie: use strndup
- formdata: use strndup
- ftp: use strndup
- gtls: use aprintf instead of malloc + strcpy * 2
- http: use strndup
- mbedtls: use strndup
- md4: use memdup
- ntlm: use memdup
- ntlm_sspi: use strndup
- pingpong: use memdup
- rtsp: use strndup instead of malloc, memcpy and null-terminate
- sectransp: use strndup
- socks_gssapi.c: use memdup
- vtls: use dynbuf instead of malloc, snprintf and memcpy
- vtls: use strdup instead of malloc + memcpy
- wolfssh: use strndup

Closes #12453

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lib: add and use Curl_strndup()

The Curl_strndup() function is similar to memdup(), but copies 'n' bytes
then adds a terminating null byte ('\0').

Closes #12251

configure: check for the fseeko declaration too

... and make the code require both symbol and declaration.

This is because for Android, the symbol is always present in the lib at

configure: check for the fseeko declaration too

... and make the code require both symbol and declaration.

This is because for Android, the symbol is always present in the lib at
build-time even when not actually available in run-time.

Assisted-by: Viktor Szakats
Reported-by: 12932 on github
Fixes #12086
Closes #12158

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spelling: fix codespell 2.2.6 typos

Closes #12019

lib: use wrapper for curl_mime_data fseek callback

fseek uses long offset which does not match with curl_off_t. This leads
to undefined behavior when calling the callback and caused fail

lib: use wrapper for curl_mime_data fseek callback

fseek uses long offset which does not match with curl_off_t. This leads
to undefined behavior when calling the callback and caused failure on
arm 32 bit.

Use a wrapper to solve this and use fseeko which uses off_t instead of
long.

Thanks to the nice people at Libera IRC #musl for helping finding this
out.

Fixes #11882
Fixes #11900
Closes #11918

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configure, cmake, lib: more form api deprecation

Introduce a --enable-form-api configure option to control its inclusion
in builds. The condition name defined for it is CURL_DISABLE_FORM

configure, cmake, lib: more form api deprecation

Introduce a --enable-form-api configure option to control its inclusion
in builds. The condition name defined for it is CURL_DISABLE_FORM_API.

Form api code is dependent of MIME: configure and CMake handle this
dependency automatically: CMake by making it a dependent option
explicitly, configure by inheriting the MIME value by default and
rejecting explicit incompatible values.

"form-api" is now a new hidden test feature.

Update libcurl modules to respect this option and adjust tests
accordingly.

Closes #9621

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copyright: update all copyright lines and remove year ranges

- they are mostly pointless in all major jurisdictions
- many big corporations and projects already don't use them
- save

copyright: update all copyright lines and remove year ranges

- they are mostly pointless in all major jurisdictions
- many big corporations and projects already don't use them
- saves us from pointless churn
- git keeps history for us
- the year range is kept in COPYING

checksrc is updated to allow non-year using copyright statements

Closes #10205

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mime: relax easy/mime structures binding

Deprecation and removal of codeset conversion support from the library
have released the strict need for an early binding of mime structures to

mime: relax easy/mime structures binding

Deprecation and removal of codeset conversion support from the library
have released the strict need for an early binding of mime structures to
an easy handle (https://github.com/curl/curl/commit/2610142).

This constraint currently forces to create the handle before the mime
structure and the latter cannot be attached to another handle once
created (see https://curl.se/mail/lib-2022-08/0027.html).

This commit removes the handle pointers from the mime structures
allowing more flexibility on their use.

When an easy handle is duplicated, bound mime structures must however
still be duplicated too as their components hold send-time dynamic
information.

Closes #9927

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lib: fix some type mismatches and remove unneeded typecasts

Many of these castings are unneeded if we change the variables to work
better with each other.

Ref: https://github.co

lib: fix some type mismatches and remove unneeded typecasts

Many of these castings are unneeded if we change the variables to work
better with each other.

Ref: https://github.com/curl/curl/pull/9823

Closes https://github.com/curl/curl/pull/9835

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misc: typo and grammar fixes

- Replace `Github` with `GitHub`.
- Replace `windows` with `Windows`
- Replace `advice` with `advise` where a verb is used.
- A few fixes on removing

misc: typo and grammar fixes

- Replace `Github` with `GitHub`.
- Replace `windows` with `Windows`
- Replace `advice` with `advise` where a verb is used.
- A few fixes on removing repeated words.
- Replace `a HTTP` with `an HTTP`

Closes #9802

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formdata: typecast the va_arg return value

To avoid "enumerated type mixed with another type" warnings

Follow-up from 0f52dd5fd5aa3592691a

Closes #9499

formdata: fix warning: 'CURLformoption' is promoted to 'int'

curl/lib/formdata.c: In function 'FormAdd':
curl/lib/formdata.c:249:31: warning: 'CURLformoption' is promoted to 'int' when p

formdata: fix warning: 'CURLformoption' is promoted to 'int'

curl/lib/formdata.c: In function 'FormAdd':
curl/lib/formdata.c:249:31: warning: 'CURLformoption' is promoted to 'int' when passed through '...'
249 | option = va_arg(params, CURLformoption);
| ^
curl/lib/formdata.c:249:31: note: (so you should pass 'int' not 'CURLformoption' to 'va_arg')
curl/lib/formdata.c:249:31: note: if this code is reached, the program will abort

Closes #9484

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copyright: make repository REUSE compliant

Add licensing and copyright information for all files in this repository. This
either happens in the file itself as a comment header or in the

copyright: make repository REUSE compliant

Add licensing and copyright information for all files in this repository. This
either happens in the file itself as a comment header or in the file
`.reuse/dep5`.

This commit also adds a Github workflow to check pull requests and adapts
copyright.pl to the changes.

Closes #8869

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lib: remove support for CURL_DOES_CONVERSIONS

TPF was the only user and support for that was dropped.

Closes #8378

formdata: avoid size_t => long typecast overflows

Typically a problem for platforms with 32 bit long and 64 bit size_t

Reported-by: Fabian Yamaguchi
Bug: https://hackerone.com/r

formdata: avoid size_t => long typecast overflows

Typically a problem for platforms with 32 bit long and 64 bit size_t

Reported-by: Fabian Yamaguchi
Bug: https://hackerone.com/reports/1444539
Closes #8272

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formdata: avoid "Argument cannot be negative" warning

... when converting a curl_off_t to size_t, by using
CURL_ZERO_TERMINATED before passing the argument to the function.

Dete

formdata: avoid "Argument cannot be negative" warning

... when converting a curl_off_t to size_t, by using
CURL_ZERO_TERMINATED before passing the argument to the function.

Detected by Coverity CID 1486590.

Closes #7328
Assisted-by: Daniel Gustafsson

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formdata: correct typecast in curl_mime_data call

Coverity pointed out it the mismatch. CID 1486590

Closes #7327

curl.se: new home

Closes #6172

terminology: call them null-terminated strings

Updated terminology in docs, comments and phrases to refer to C strings
as "null-terminated". Done to unify with how most other C oriented

terminology: call them null-terminated strings

Updated terminology in docs, comments and phrases to refer to C strings
as "null-terminated". Done to unify with how most other C oriented docs
refer of them and what users in general seem to prefer (based on a
single highly unscientific poll on twitter).

Reported-by: coinhubs on github
Fixes #5598
Closes #5608

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source cleanup: remove all custom typedef structs

- Stick to a single unified way to use structs
- Make checksrc complain on 'typedef struct {'
- Allow them in tests, public heade

source cleanup: remove all custom typedef structs

- Stick to a single unified way to use structs
- Make checksrc complain on 'typedef struct {'
- Allow them in tests, public headers and examples

- Let MD4_CTX, MD5_CTX, and SHA256_CTX typedefs remain as they actually
typedef different types/structs depending on build conditions.

Closes #5338

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mime: latch last read callback status.

In case a read callback returns a status (pause, abort, eof,
error) instead of a byte count, drain the bytes read so far but
remember this stat

mime: latch last read callback status.

In case a read callback returns a status (pause, abort, eof,
error) instead of a byte count, drain the bytes read so far but
remember this status for further processing.
Takes care of not losing data when pausing, and properly resume a
paused mime structure when requested.
New tests 670-673 check unpausing cases, with easy or multi
interface and mime or form api.

Fixes #4813
Reported-by: MrdUkk on github

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formdata/mime: copyright year range update

Due to the merge/revert cycle

Revert "mime: latch last read callback status."

This reverts commit 87869e38d7afdec3ef1bb4965711458b088e254f.

Fixes #5014
Closes #5015
Reopens #4833