Compiling a program on termux aarch64 produces `FileNotFound` errors

[DivergentClouds]

Zig Version

0.11.0-dev.1012+4b5fc5239

Steps to Reproduce and Observed Behavior

Steps to reproduce

• Install Termux (not the google play version, as that's is deprecated and has security flaws) on an aarch64 Android phone
• Download the master aarch64 Linux tarball from ziglang.org and extract it
• Run zig init-exe && zig build run

Observed Behavior

info: Created build.zig
info: Created src/main.zig
info: Next, try `zig build --help` or `zig build run`
warning: Encountered error: FileNotFound, falling back to default ABI and dynamic linker.

warning: Encountered error: FileNotFound, falling back to default ABI and dynamic linker.

warning: Encountered error: FileNotFound, falling back to default ABI and dynamic linker.

warning: Encountered error: FileNotFound, falling back to default ABI and dynamic linker.

warning: Encountered error: FileNotFound, falling back to default ABI and dynamic linker.

warning: Encountered error: FileNotFound, falling back to default ABI and dynamic linker.

warning: Encountered error: FileNotFound, falling back to default ABI and dynamic linker.

warning: Encountered error: FileNotFound, falling back to default ABI and dynamic linker.

All your codebase are belong to us.
Run `zig build test` to run the tests.

Interestingly, the outputted program behaves as expected, although I'm not sure if more complex programs would break.

Expected Behavior

The program should compile with no errors and run properly.

[DivergentClouds]

The same eight FileNotFound errors appear with this code:

// main.zig
pub fn main() void {}

Running zig build-exe rather than zig build only produces the error once.

[DivergentClouds]

zig targets will produce the error once as well.

[mikdusan]

can you show the output of the following 2 commands, where my_name_exe is what zig build-exe produces

ldd /usr/bin/env
ldd my_main_exe

[DivergentClouds]

/usr/ on android with termux is located at /data/data/com.termux/files/usr/, so I did ldd /data/data/com.termux/usr/etc/env with that in mind

	libandroid-support.so => /data/data/com.termux/files/usr/lib/libandroid-support.so
	libgmp.so => /data/data/com.termux/files/usr/lib/libgmp.so
	libiconv.so => /data/data/com.termux/files/usr/lib/libiconv.so
	libc.so => /system/lib64/libc.so
	ld-android.so => /system/lib64/ld-android.so
	libdl.so => /system/lib64/libdl.so

ldd main doesn't give any output (main is the executable)

[mikdusan]

Hmm perhaps the zig executable you are using has a dynamic linker path that is not found on your host. Maybe ldd against zig can shed some light.

[DivergentClouds]

ldd on zig also doesn't give any output :/

I found the native ldd on my system it was in /system/bin/ (i had downloaded gnu ldd before and it was having some weird issues). The native ldd actually has some potentially useful results! Upon running it on either the zig executable it says error: "/data/data/com.termux/files/home/coding/tools/zig/zig" has unexpected e_type: 2

On Android, ldd is a shell script that runs either linker --list or linker64 --list depending on if the executable is 32 or 64 bit. I'm gonna look at the linker64 source code to try to find out what the e_type means.

[DivergentClouds]

e_type: 2 is part of an ELF header and marks something as an executable. I found this in the Android source code for the linker:

  if (header_.e_type != ET_DYN) {
    DL_ERR("\"%s\" has unexpected e_type: %d", name_.c_str(), header_.e_type);
    return false;
  }

So it seems like that error might be unrelated.

[mikdusan]

That looks like it is expecting a dynamic executable and iirc zig shipped in tarballs for linux are static for maximum platform compatibility. But yeah, unrelated.

[DivergentClouds]

zig cc potentially gave a hint!

$ zig cc main.c
warning: Encountered error: FileNotFound, falling back to default ABI and dynamic linker.

error: unable to create compilation: LibCRuntimeNotFound

I think that since Android has a non-standard filesystem layout it doesn't know where to look for libraries.

[DivergentClouds]

Things seem to work fine from within proot-distro, which emulates a standard filesystem (among other things), I think this is a point in favor of Android's filesystem being the source of the problem.

[djpohly]

Edit: you can probably disregard this; I think I was conflating two different issues.

---

In src/libc_installation.zig the findNativeCrtDirPosix() function looks for crt1.o with the command

cc -print-file-name=crt1.o

but this fails on Termux. There may be a useful hint here that the filename to search for in this system is crtbegin_dynamic.o instead. Maybe?

[The-King-of-Toasters]

I think this is a pretty easy fix. Termux root userspace is at /data/data/com.termux/files/, and usr is located there. Therefore the location for /usr/bin/env is actually /data/data/com.termux/files/usr/bin/env. If you replace /usr/bin/env with this location in zig/system/NativeTargetInfo.zig, the error goes away.

The solution then would be to detect if we're running on Termux and alter the path accordingly. It seems that $SHELL, $PREFIX, $HOME and $LD_PRELOAD are all prefixed with /data....