Unable to build LVGL samples on Ubuntu 22.04 for `native_sim`

[pdgendt]

Describe the bug

When trying to build for example samples/modules/lvgl/demos for native_sim/native/64 on Ubuntu 22.04 this fails because of an undefined reference to strlcpy.

Regression since: #92898

Regression

• This is a regression.

Steps to reproduce

Tested on a docker instance

docker run -it ubuntu:22.04

After following the getting started guide run

west build -p -b native_sim/native/64 samples/modules/lvgl/demos/

Relevant log output

[519/521] Linking C executable zephyr/zephyr.elf
Generating files from /root/zephyrproject/zephyr/build/zephyr/zephyr.elf for board: native_sim
[520/521] Building native simulator runner, and linking final executable
FAILED: zephyr/CMakeFiles/native_runner_executable zephyr/zephyr.exe /root/zephyrproject/zephyr/build/zephyr/CMakeFiles/native_runner_executable /root/zephyrproject/zephyr/build/zephyr/zephyr.exe
cd /root/zephyrproject/zephyr/build/zephyr && /usr/bin/make -f /root/zephyrproject/zephyr/scripts/native_simulator/Makefile all --warn-undefined-variables -r NSI_CONFIG_FILE=/root/zephyrproject/zephyr/build/zephyr/NSI/nsi_config
/usr/bin/ld: /root/zephyrproject/zephyr/build/zephyr/NSI/root/zephyrproject/zephyr/build/zephyr/zephyr.elf.loc_cpusw.o: undefined reference to symbol 'strlcpy@@LIBBSD_0.0'
/usr/bin/ld: /lib/x86_64-linux-gnu/libbsd.so.0: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
make: *** [/root/zephyrproject/zephyr/scripts/native_simulator/Makefile:142: /root/zephyrproject/zephyr/build/zephyr/zephyr.exe] Error 1
ninja: build stopped: subcommand failed.
FATAL ERROR: command exited with status 1: /usr/bin/cmake --build /root/zephyrproject/zephyr/build

Impact

Annoyance – Minor irritation; no significant impact on usability or functionality.

Environment

• OS: Ubuntu 22.04
• Toolchain: Zephyr SDK 0.17.2
• Commit: 96d062a

Additional Context

No response

[pdgendt]

The issue appears to be related to the glibc version. strlcpy has been added to version 2.38 and Ubuntu 22.04 (jammy) still has version 2.35.

[JarmouniA]

As a fix, we should remove

#define lv_strlcpy strlcpy
#define lv_strcat   strcat

from modules/lvgl/include/lv_conf.h

[pdgendt]

As a fix, we should remove

There's no issue with strcat.

Simply removing the lv_strlcpy define is not enough, it's currently an all-or-nothing thing in LVGL for the stubs. It could be a glibc specific fix, like:

#if defined(__GLIBC__) 
#if (__GLIBC__ == 2) && (__GLIBC_MINOR__ < 38)
/* some strlcpy implementation */
#endif
#endif

But I doubt we should be making these kind of patches.

[aescolar]

My two cent: strlcpy is not standard, and not one of the functions we can expect in general when building with Zephyr https://docs.zephyrproject.org/4.1.0/contribute/coding_guidelines/index.html#rule-a-4-c-standard-library-usage-restrictions-in-zephyr-kernel
So as such it is not nice of lvgl to expect it, and I'd say it should stop using it.
(strlcpy may or may not be standardized, see for ex. https://lwn.net/Articles/905777/ about strlcpy and strscpy)
lvgl could either use strncpy or define its own version with a different name than this pseudo-standard ones (but this sounds quite overkill).
(Note relevant comment in discord https://discord.com/channels/720317445772017664/883450516527513660/1400824586953691248 )

As an immediate workaround I could have suggested building with Picolibc, but it also seems to not build in a related way (#93986)

Note another quite ugly workaround: https://stackoverflow.com/questions/67360010/undefined-reference-to-strlcpy-and-strlcat

[HenryXin]

I can run the example project with this modification
diff --git a/samples/subsys/display/lvgl/CMakeLists.txt b/samples/subsys/display/lvgl/CMakeLists.txt
index f2f9a2689f1..a49376abda1 100644
--- a/samples/subsys/display/lvgl/CMakeLists.txt
+++ b/samples/subsys/display/lvgl/CMakeLists.txt
@@ -7,3 +7,4 @@ project(lvgl)

FILE(GLOB app_sources src/*.c)
target_sources(app PRIVATE ${app_sources})
+target_link_libraries(app PRIVATE bsd)

Then build:
west build -b native_sim/native/64 --pristine

and run:
west build -t run

[pdgendt]

Hi @HenryXin a fix has been submitted in #94073