Zephyr defines POSIX values which already appear in limits.h

[keith-packard]

Describe the bug Upstream picolibc includes definitions for various minimum values in limits.h that are required by POSIX including _POSIX_NAME_MAX and _POSIX_PATH_MAX. Zephyr is redefining these in include/zephyr/posix/posix_features.h.

To Reproduce

1. Download toolchain built against current picolibc development branch: https://github.com/zephyrproject-rtos/sdk-ng/actions/runs/11503233418/artifacts/2100796287
2. west twister -p qemu_malta -s tests/lib/c_lib/thrd/libraries.libc.c11_threads.picolibc
3. See error

Expected behavior Successful test run

Impact Cannot migrate picolibc to upstream development version

Logs and console output

[81/147] Building C object zephyr/lib/posix/options/CMakeFiles/lib__posix__options.dir/sysconf.c.obj
FAILED: zephyr/lib/posix/options/CMakeFiles/lib__posix__options.dir/sysconf.c.obj 
ccache /__w/sdk-ng/sdk-ng/tools/zephyr-sdk-0.17.0-8-g6fd2e1d/mips-zephyr-elf/bin/mips-zephyr-elf-gcc -DKERNEL -DK_HEAP_MEM_POOL_SIZE=1024 -DPICOLIBC_LONG_LONG_PRINTF_SCANF -DTC_RUNID=020f12a965888084e31d7f59ce1d46d3 -D__LINUX_ERRNO_EXTENSIONS__ -D__ZEPHYR__=1 -I/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/kernel/include -I/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/arch/mips/include -I/__w/sdk-ng/sdk-ng/test/twister-out/qemu_malta/tests/lib/c_lib/thrd/libraries.libc.c11_threads.picolibc/zephyr/include/generated/zephyr -I/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/include -I/__w/sdk-ng/sdk-ng/test/twister-out/qemu_malta/tests/lib/c_lib/thrd/libraries.libc.c11_threads.picolibc/zephyr/include/generated -I/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/soc/qemu/malta -I/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/include/zephyr/posix -I/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/soc/qemu/malta/. -I/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/subsys/testsuite/include -I/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/subsys/testsuite/coverage -I/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/subsys/testsuite/ztest/include -isystem /__w/sdk-ng/sdk-ng/zephyrproject/zephyr/lib/libc/common/include -Os -DNDEBUG -Wshadow -fno-strict-aliasing -Werror -Os -imacros /__w/sdk-ng/sdk-ng/test/twister-out/qemu_malta/tests/lib/c_lib/thrd/libraries.libc.c11_threads.picolibc/zephyr/include/generated/zephyr/autoconf.h -fno-printf-return-value -fno-common -g -gdwarf-4 -fdiagnostics-color=always -EL -msoft-float -G0 -mno-gpopt -fno-pic -pipe --sysroot=/__w/sdk-ng/sdk-ng/tools/zephyr-sdk-0.17.0-8-g6fd2e1d/mips-zephyr-elf/mips-zephyr-elf -imacros /__w/sdk-ng/sdk-ng/zephyrproject/zephyr/include/zephyr/toolchain/zephyr_stdint.h -Wall -Wformat -Wformat-security -Wno-format-zero-length -Wdouble-promotion -Wno-pointer-sign -Wpointer-arith -Wexpansion-to-defined -Wno-unused-but-set-variable -Werror=implicit-int -fno-pie -fno-asynchronous-unwind-tables -fno-reorder-functions --param=min-pagesize=0 -fno-defer-pop -fmacro-prefix-map=/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/tests/lib/c_lib/thrd=CMAKE_SOURCE_DIR -fmacro-prefix-map=/__w/sdk-ng/sdk-ng/zephyrproject/zephyr=ZEPHYR_BASE -fmacro-prefix-map=/__w/sdk-ng/sdk-ng/zephyrproject=WEST_TOPDIR -ffunction-sections -fdata-sections --specs=picolibc.specs -D_POSIX_THREADS -mips32 -std=c99 -MD -MT zephyr/lib/posix/options/CMakeFiles/lib__posix__options.dir/sysconf.c.obj -MF zephyr/lib/posix/options/CMakeFiles/lib__posix__options.dir/sysconf.c.obj.d -o zephyr/lib/posix/options/CMakeFiles/lib__posix__options.dir/sysconf.c.obj -c /__w/sdk-ng/sdk-ng/zephyrproject/zephyr/lib/posix/options/sysconf.c
In file included from /__w/sdk-ng/sdk-ng/zephyrproject/zephyr/include/zephyr/posix/signal.h:10,
                 from /__w/sdk-ng/sdk-ng/zephyrproject/zephyr/include/zephyr/posix/time.h:62,
                 from /__w/sdk-ng/sdk-ng/zephyrproject/zephyr/include/zephyr/posix/pthread.h:14,
                 from /__w/sdk-ng/sdk-ng/zephyrproject/zephyr/lib/posix/options/sysconf.c:9:
/__w/sdk-ng/sdk-ng/zephyrproject/zephyr/include/zephyr/posix/posix_features.h:241: error: "_POSIX_AIO_LISTIO_MAX" redefined [-Werror]
  241 | #define _POSIX_AIO_LISTIO_MAX               (2)
      | 
In file included from /__w/sdk-ng/sdk-ng/tools/zephyr-sdk-0.17.0-8-g6fd2e1d/mips-zephyr-elf/picolibc/include/limits.h:6,
                 from /__w/sdk-ng/sdk-ng/zephyrproject/zephyr/include/zephyr/kernel_includes.h:22,
                 from /__w/sdk-ng/sdk-ng/zephyrproject/zephyr/include/zephyr/kernel.h:17,
                 from /__w/sdk-ng/sdk-ng/zephyrproject/zephyr/include/zephyr/posix/pthread.h:13:
/__w/sdk-ng/sdk-ng/tools/zephyr-sdk-0.17.0-8-g6fd2e1d/mips-zephyr-elf/picolibc/include/sys/syslimits.h:63: note: this is the location of the previous definition
   63 | #define _POSIX_AIO_LISTIO_MAX   2

Environment (please complete the following information):

• OS: Linux
• Toolchain Zephyr SDK development version

[cfriedt]

I would guess that an ifndef might not be sufficient here, since that value should probably be configurable via Kconfig (if it isn't already).

What are your thoughts here @keith-packard ?

[keith-packard]

I would guess that an ifndef might not be sufficient here, since that value should probably be configurable via Kconfig (if it isn't already).

What are your thoughts here @keith-packard ?

All of these constants actually have fixed values defined by POSIX, so #ifndef would be completely fine. You probably only need to check one of them?

[cfriedt]

Just landed 🛬 - this should be easy enough to fix quickly.

[keith-packard]

as we both try to track POSIX in parallel. Thanks for taking a look; hope your travel is going well.