Fix Windows/MinGW build: missing err.h, uninitialized pointer in stdlib.c - #29
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Fix Windows/MinGW build: missing err.h, uninitialized pointer in stdlib.c#29doomfrawen wants to merge 1 commit into
doomfrawen wants to merge 1 commit into
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…ib.c - src/nfc-utils.h/.c and src/windows.h include <err.h>, a BSD/glibc-only header not shipped by MinGW-w64, so the GNU-toolchain build (autoreconf + gcc, as opposed to the VS2019/clang-cl path this repo also supports) fails with 'err.h: No such file or directory'. windows.h doesn't call anything from it, so that include is simply dropped. nfc-utils.h's DBG/WARN/ERR macros do use warnx(), so on _WIN32 this adds a small static inline warnx() shim instead of the header, and drops the redundant second #include <err.h> in nfc-utils.c. - src/stdlib.c's setenv()/unsetenv() declare 'char *str[32]' (an array of 32 uninitialized pointers) and then do strcpy(*str, name) etc, which dereferences the first (uninitialized/garbage) pointer in that array and writes through it - undefined behavior, not just a compile-time type mismatch. Changed to 'char str[32]' (an actual 32-byte buffer) and dropped the erroneous dereferences.
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Building mfoc-hardnested for native Windows via the GNU toolchain path (
autoreconf -vis && ./configure && make, MSYS2 MinGW64) rather than the VS2019/clang-cl path hits two issues:1.
src/nfc-utils.h/.c,src/windows.h— include<err.h>, a BSD/glibc-only header not shipped by MinGW-w64, so the build fails witherr.h: No such file or directory.windows.hdoesn't call anything from it, so that include is simply dropped.nfc-utils.h's DBG/WARN/ERR macros do usewarnx(), so on_WIN32this adds a smallstatic inline warnx()shim instead of the header, and drops the now-redundant second#include <err.h>in nfc-utils.c.2.
src/stdlib.c—setenv()/unsetenv()declarechar *str[32](an array of 32 uninitialized pointers) and then dostrcpy(*str, name)etc, which dereferences the first garbage pointer in that array and writes through it. This is undefined behavior / a likely crash, not just a compile-time type mismatch (worth noting: this is a different, worse variant of a bug also present in upstream libnfc's contrib/win32/stdlib.c, which just declares the array without dereferencing it and so only fails to compile rather than corrupting memory). Changed tochar str[32](an actual 32-byte stack buffer) and removed the erroneous*dereferences.Both fixes are additive/platform-scoped and don't touch the existing VS/clang-cl build path or non-Windows behavior.