esp32: Undocumented dependency of libpython2

[adalava]

The following error message is seen when building esp32 on a system without python2 installed:

/home/alfredoj/.espressif/tools/zephyr/xtensa-esp32-elf/bin/xtensa-esp32-elf-gdb: error while loading shared libraries: libpython2.7.so.1.0: cannot open shared object file: No such file or directory
I think it's undocumented dependency, but depends on python3 instead would be nice, if possible.

Fix/workaround: sudo apt install libpython2.7

To Reproduce

1. Fresh install Ubuntu 20.04
2. Install zephyr
3. Install espressif tools https://docs.zephyrproject.org/latest/boards/xtensa/esp32/doc/index.html
4. Run: west build -b esp32 samples/hello_world

Expected behavior
Run without errors. The gdb console should appear when executing /home/alfredoj/.espressif/tools/zephyr/xtensa-esp32-elf/bin/xtensa-esp32-elf-gdb

Impact
gdb debugger not working.
Environment (please complete the following information):

• OS: Ubuntu 20.04
• Toolchain: espressif
• 4dedae5

[b0661]

Adding -DPYTHON=${PYTHON_EXECUTABLE} before here

zephyr/boards/xtensa/esp32/CMakeLists.txt

Line 21 in 4dedae5

-DPYTHON_DEPS_CHECKED=1

made it work in my Ubuntu 20.04 environment.

There is no real dependency on Python2. It perfectly works with Python3.

[carlescufi]

That's a bit strange, maybe you need something like this somewhere else?
#38749

[sylvioalves]

@adalava, it is not clear to me yet whether this error occurs during west build or when executing xtensa-esp32-elf-gdb manually. What is the correct case?
In case you are debugging it manually, would you try this? #38557
After flashing, just run west debug and it shall run gdb.

[adalava]

@adalava, it is not clear to me yet whether this error occurs during west build or when executing xtensa-esp32-elf-gdb manually. What is the correct case? In case you are debugging it manually, would you try this? #38557 After flashing, just run west debug and it shall run gdb.

Hi @sylvioalves, the error occurs on both cases (west build and executing xtensa-esp32-elf-gdb manually). On west build it's seen during first build (cmake step, I remove the build folder to reproduce again), but build continues normally. I don't think #38557 is related to this specific problem since the libpython2.7.so.1.0 library is missing on the system and gdb binary isn't being loaded.

If you look at binary, it's linked against libpython2.7.so.1, so I'm guessing your machine has at least libpython2 installed. Here's the ldd output:

# removed libpython2 with: sudo apt remove libpython2.7

$ ldd /home/alfredoj/.espressif/tools/zephyr/xtensa-esp32-elf/bin/xtensa-esp32-elf-gdb
	linux-vdso.so.1 (0x00007ffcec9a7000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f9a275be000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f9a2759b000)
	libutil.so.1 => /lib/x86_64-linux-gnu/libutil.so.1 (0x00007f9a27596000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f9a27447000)
	libpython2.7.so.1.0 => not found
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9a27255000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f9a275da000)

[sylvioalves]

I have the same env as you (no python 2.7 related tools):

sylvio@pc:~/projects/espressif/zephyr/zephyr$ ldd ~/.espressif/tools/zephyr/xtensa-esp32-elf/bin/xtensa-esp32-elf-gdb
	linux-vdso.so.1 (0x00007ffcba97a000)
	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fe55b621000)
	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fe55b5fe000)
	libutil.so.1 => /lib/x86_64-linux-gnu/libutil.so.1 (0x00007fe55b5f9000)
	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fe55b4aa000)
	libpython2.7.so.1.0 => not found
	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fe55b2b8000)
	/lib64/ld-linux-x86-64.so.2 (0x00007fe55b647000)

but no issues when building. So I am wondering what would be the diff right now.

Editing: west build works fine. GDB debugging fails due to missing 2.7. I'll document and/or update the toolchain.

[adalava]

Thanks!
You can see the error message during west build bellow, right after "-- Found toolchain:", but yes, the build works fine.

$ rm -rf build/
$ west build -b esp32 samples/hello_world
-- west build: generating a build system
Including boilerplate (Zephyr base): /home/alfredoj/zephyrproject/zephyr/cmake/app/boilerplate.cmake
-- Application: /home/alfredoj/zephyrproject/zephyr/samples/hello_world
-- Zephyr version: 2.7.99 (/home/alfredoj/zephyrproject/zephyr), build: v2.7.0-rc3-315-g4dedae5861a9
-- Found Python3: /usr/bin/python3.8 (found suitable exact version "3.8.10") found components: Interpreter 
-- Found west (found suitable version "0.11.1", minimum required is "0.7.1")
-- Board: esp32
-- Cache files will be written to: /home/alfredoj/.cache/zephyr
-- Found dtc: /usr/bin/dtc (found suitable version "1.5.0", minimum required is "1.4.6")
-- Found BOARD.dts: /home/alfredoj/zephyrproject/zephyr/boards/xtensa/esp32/esp32.dts
-- Generated zephyr.dts: /home/alfredoj/zephyrproject/zephyr/build/zephyr/zephyr.dts
-- Generated devicetree_unfixed.h: /home/alfredoj/zephyrproject/zephyr/build/zephyr/include/generated/devicetree_unfixed.h
-- Generated device_extern.h: /home/alfredoj/zephyrproject/zephyr/build/zephyr/include/generated/device_extern.h
-- Including generated dts.cmake file: /home/alfredoj/zephyrproject/zephyr/build/zephyr/dts.cmake
Parsing /home/alfredoj/zephyrproject/zephyr/Kconfig
Loaded configuration '/home/alfredoj/zephyrproject/zephyr/boards/xtensa/esp32/esp32_defconfig'
Merged configuration '/home/alfredoj/zephyrproject/zephyr/samples/hello_world/prj.conf'
Configuration saved to '/home/alfredoj/zephyrproject/zephyr/build/zephyr/.config'
Kconfig header saved to '/home/alfredoj/zephyrproject/zephyr/build/zephyr/include/generated/autoconf.h'
-- Found toolchain: espressif (/home/alfredoj/.espressif/tools/zephyr)
/home/alfredoj/.espressif/tools/zephyr/xtensa-esp32-elf/bin/xtensa-esp32-elf-gdb: error while loading shared libraries: libpython2.7.so.1.0: cannot open shared object file: No such file or directory
-- The C compiler identification is GNU 8.4.0
-- The CXX compiler identification is GNU 8.4.0
-- The ASM compiler identification is GNU
-- Found assembler: /home/alfredoj/.espressif/tools/zephyr/xtensa-esp32-elf/bin/xtensa-esp32-elf-gcc
-- Configuring done
-- Generating done
-- Build files have been written to: /home/alfredoj/zephyrproject/zephyr/build
-- west build: building application
[1/154] Preparing syscall dependency handling
..
..
..
..

esptool.py v3.1-dev
Merged 5 ELF sections

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