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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

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checksrc

This is the tool we use within the curl project to scan C source code and check that it adheres to our Source Code Style guide.

Usage

checksrc.pl [options] [file1] [file2] ...

Command line options

-W[file] skip that file and exclude it from being checked. Helpful when, for example, one of the files is generated.

-D[dir] directory name to prepend to filenames when accessing them.

-h shows the help output, that also lists all recognized warnings

What does `checksrc` warn for?

checksrc does not check and verify the code against the entire style guide. The script is an effort to detect the most common mistakes and syntax mistakes that contributors make before they get accustomed to our code style. Heck, many of us regulars do the mistakes too and this script helps us keep the code in shape.

checksrc.pl -h

Lists how to use the script and it lists all existing warnings it has and problems it detects. At the time of this writing, the existing checksrc warnings are:

ASSIGNWITHINCONDITION: Assignment within a conditional expression. The code style mandates the assignment to be done outside of it.
ASTERISKNOSPACE: A pointer was declared like char* name instead of the more appropriate char *name style. The asterisk should sit next to the name.
ASTERISKSPACE: A pointer was declared like char * name instead of the more appropriate char *name style. The asterisk should sit right next to the name without a space in between.
BADCOMMAND: There is a bad checksrc instruction in the code. See the Ignore certain warnings section below for details.
BANNEDFUNC: A banned function was used. The functions sprintf, vsprintf, strcat, strncat, gets are never allowed in curl source code.
BRACEELSE: '} else' on the same line. The else is supposed to be on the following line.
BRACEPOS: wrong position for an open brace ({).
BRACEWHILE: more than once space between end brace and while keyword
COMMANOSPACE: a comma without following space
COPYRIGHT: the file is missing a copyright statement
CPPCOMMENTS: // comment detected, that is not C89 compliant
DOBRACE: only use one space after do before open brace
EMPTYLINEBRACE: found empty line before open brace
EQUALSNOSPACE: no space after = sign
EQUALSNULL: comparison with == NULL used in if/while. We use !var.
EXCLAMATIONSPACE: space found after exclamations mark
FOPENMODE: curlx_fopen(), curlx_freopen() need a macro for the mode string, use it
INDENTATION: detected a wrong start column for code. Note that this warning only checks some specific places and can certainly miss many bad indentations.
LONGLINE: A line is longer than 79 columns.
MULTISPACE: Multiple spaces were found where only one should be used.
NOSPACEEQUALS: An equals sign was found without preceding space. We prefer a = 2 and not a=2.
NOTEQUALSZERO: check found using != 0. We use plain if(var).
ONELINECONDITION: do not put the conditional block on the same line as if()
OPENCOMMENT: File ended with a comment (/*) still "open".
PARENBRACE: ){ was used without sufficient space in between.
RETURNNOSPACE: return was used without space between the keyword and the following value.
SEMINOSPACE: There was no space (or newline) following a semicolon.
SIZEOFNOPAREN: Found use of sizeof without parentheses. We prefer sizeof(int) style.
SNPRINTF - Found use of snprintf(). Since we use an internal replacement with a different return code etc, we prefer curl_msnprintf().
SPACEAFTERPAREN: there was a space after open parenthesis, ( text.
SPACEBEFORECLOSE: there was a space before a close parenthesis, text ).
SPACEBEFORECOMMA: there was a space before a comma, one , two.
SPACEBEFOREPAREN: there was a space before an open parenthesis, if (, where one was not expected
SPACESEMICOLON: there was a space before semicolon, ;.
TABS: TAB characters are not allowed
TRAILINGSPACE: Trailing whitespace on the line
TYPEDEFSTRUCT: we frown upon (most) typedefed structs
UNUSEDIGNORE: a checksrc inlined warning ignore was asked for but not used, that is an ignore that should be removed or changed to get used.

Extended warnings

Some warnings are quite computationally expensive to perform, so they are turned off by default. To enable these warnings, place a .checksrc file in the directory where they should be activated with commands to enable the warnings you are interested in. The format of the file is to enable one warning per line like so: enable <EXTENDEDWARNING>

Currently these are the extended warnings which can be enabled:

COPYRIGHTYEAR: the current changeset has not updated the copyright year in the source file
STRERROR: use of banned function strerror()
STDERR: use of banned variable stderr

Ignore certain warnings

Due to the nature of the source code and the flaws of the checksrc tool, there is sometimes a need to ignore specific warnings. checksrc allows a few different ways to do this.

Inline ignore

You can control what to ignore within a specific source file by providing instructions to checksrc in the source code itself. See examples below. The instruction can ask to ignore a specific warning a specific number of times or you ignore all of them until you mark the end of the ignored section.

Inline ignores are only done for that single specific source code file.

Example

/* !checksrc! disable LONGLINE all */

This ignores the warning for overly long lines until it is re-enabled with:

/* !checksrc! enable LONGLINE */

If the enabling is not performed before the end of the file, it is enabled again automatically for the next file.

You can also opt to ignore just N violations so that if you have a single long line you just cannot shorten and is agreed to be fine anyway:

/* !checksrc! disable LONGLINE 1 */

... and the warning for long lines is enabled again automatically after it has ignored that single warning. The number 1 can of course be changed to any other integer number. It can be used to make sure only the exact intended instances are ignored and nothing extra.

Directory wide ignore patterns

This is a method we have transitioned away from. Use inline ignores as far as possible.

Make a checksrc.skip file in the directory of the source code with the false positive, and include the full offending line into this file.

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