C23 makes various standard library functions, that return a pointer into an input array, into macros that return a pointer to const when the relevant argument passed to the macro is a pointer to const. (The requirement is for macros, with the existing function types applying when macro expansion is suppressed. When a null pointer constant is passed, such as integer 0, that's the same as a pointer to non-const.) Implement this feature. This only applies to C, not C++, since such macros are not an appropriate way of doing this for C++ and all the affected functions other than bsearch have overloads to implement an equivalent feature for C++ anyway. Nothing is done to apply such a change to any non-C23 functions with the same property of returning a pointer into an input array. The feature is also disabled when _LIBC is defined, since there are various places in glibc that either redefine these identifiers as macros, or define the functions themselves, and would need changing to work in the presence of these macro definitions. A natural question is whether we should in fact change those places and not disable the macro definitions for _LIBC. If so, we'd need a solution for the places in glibc that define the macro *before* including the relevant header (in order in effect to disable the header declaration of the function by renaming that declaration). One testcase has #undef added to avoid conflicting with this feature and another has const added; -Wno-discarded-qualifiers is added for building zic (but could be removed once there's a new upstream tzcode release that's const-safe with this C23 change and glibc has updated to code from that new release). Probably other places in glibc proper would need const added if we remove the _LIBC conditionals. Another question would be whether some GCC extension should be added to support this feature better with macros that only expand each argument once (as well as reducing duplication of diagnostics for bad usages such as non-pointer and pointer-to-volatile-qualfied arguments). Tested for x86_64.
The -Wp does not work properly if the compiler is configured to enable fortify by default, since it bypasses the compiler driver (which defines the fortify flags in this case). This patch is similar to the one used on Ubuntu [1]. I checked with a build for x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, s390x-linux-gnu, and riscv64-linux-gnu with gcc-13 that enables the fortify by default. Co-authored-by: Matthias Klose <matthias.klose@canonical.com> [1] https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/glibc/tree/debian/patches/ubuntu/fix-fortify-source.patch Reviewed-by: DJ Delorie <dj@redhat.com>
Rename the identifier sz to __sz everywhere.
Fixes: a643f60c53 ("Make sure that the fortified function conditionals are constant")
Add string/test-strncmp-nonarray and wcsmbs/test-wcsncmp-nonarray. This is the test that uncovered bug 31934. Test run time is more than one minute on a fairly current system, so turn these into xtests that do not run automatically. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
This commit adds string/test-strnlen-nonarray and wcsmbs/test-wcsnlen-nonarray. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
It uses the same two-way algorithm used on strstr, strcasestr, and memmem. Different than strstr, neither the "shift table" optimization nor the self-adapting filtering check is used because it would result in a too-large shift table (and it also simplifies the implementation bit). Checked on x86_64-linux-gnu and aarch64-linux-gnu. Reviewed-by: DJ Delorie <dj@redhat.com>
Parametrize test-strstr.c so it can be used to check wcsstr. Checked on x86_64-linux-gnu and aarch64-linux-gnu. Reviewed-by: DJ Delorie <dj@redhat.com>
It improve fortify checks for wmemcpy, wmemmove, wmemset, wcscpy, wcpcpy, wcsncpy, wcpncpy, wcscat, wcsncat, wcslcpy, wcslcat, swprintf, fgetws, fgetws_unlocked, wcrtomb, mbsrtowcs, wcsrtombs, mbsnrtowcs, and wcsnrtombs. The compile and runtime checks have similar coverage as with GCC. Checked on aarch64, armhf, x86_64, and i686. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
Complete the internal renaming from "C2X" and related names in GCC by renaming *-c2x and *-gnu2x tests to *-c23 and *-gnu23. Tested for x86_64, and with build-many-glibcs.py for powerpc64le.