build: avoid overriding system open and stat symbols#18776
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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 b12da22 #18866 Follow-up to db98daa #18844 Follow-up to 4deea93 #18814 Follow-up to 9678ff5 #18776 Follow-up to 10bac43 #18774 Follow-up to 20142f5 #18634 Follow-up to bf7375e #18503 Follow-up to 9863599 #18502 Follow-up to 3bb5e58 #17827 Closes #19626
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Replace them by
curlx_open()andcurlx_stat().To make it obvious in the source code what is being executed.
Also:
open()for test servers.This is critical for the call made from the signal handler.
For other calls, it's an option to use
curlx_open(), butdoesn't look important enough to do it, following the path
taken with
fopen().Follow-up to 10bac43 #18774
Follow-up to 20142f5 #18634
Follow-up to bf7375e #18503