Target mips-unknown-linux-musl and mipsel-unknown-linux-musl are not statically linked.

[abcfy2]

Here issue is from: rust-lang/cargo#9039

Meta

rustc --version --verbose:

rustc 1.49.0 (e1884a8e3 2020-12-29)
binary: rustc
commit-hash: e1884a8e3c3e813aada8254edfa120e85bf5ffca
commit-date: 2020-12-29
host: x86_64-unknown-linux-gnu
release: 1.49.0

Problem

Target mips-unknown-linux-musl and mipsel-unknown-linux-musl are not statically linked, maybe it's an rustc issue?

Steps

1. download build toolchain from: musl.cc
2. cargo new cargo-hello && cd cargo-hello
3. cargo build --target mips-unknown-linux-musl or cargo build --target mipsel-unknown-linux-musl
4. file target/<target>/debug/cargo-hello

Here is my ~/.cargo/config

[target.aarch64-unknown-linux-musl]
linker = "/home/fengyu/projects/cross_prefix/aarch64-linux-musl-cross/bin/aarch64-linux-musl-gcc"

[target.arm-unknown-linux-musleabi]
linker = "/home/fengyu/projects/cross_prefix/arm-linux-musleabi-cross/bin/arm-linux-musleabi-gcc"

[target.mips-unknown-linux-musl]
linker = "/home/fengyu/projects/cross_prefix/mips-linux-musl-cross/bin/mips-linux-musl-gcc"

[target.mips64-unknown-linux-muslabi64]
linker = "/home/fengyu/projects/cross_prefix/mips64-linux-musl-cross/bin/mips64-linux-musl-gcc"

[target.mips64el-unknown-linux-muslabi64]
linker = "/home/fengyu/projects/cross_prefix/mips64el-linux-musl-cross/bin/mips64el-linux-musl-gcc"

[target.mipsel-unknown-linux-musl]
linker = "/home/fengyu/projects/cross_prefix/mipsel-linux-musl-cross/bin/mipsel-linux-musl-gcc"

[target.x86_64-unknown-linux-musl]
linker = "/home/fengyu/projects/cross_prefix/x86_64-linux-musl-cross/bin/x86_64-linux-musl-gcc"

I find only mips-unknown-linux-musl and mipsel-unknown-linux-musl are not staticlly linked.

$ echo aarch64-unknown-linux-musl arm-unknown-linux-musleabi mips-unknown-linux-musl mips64-unknown-linux-muslabi64 mips64el-unknown-linux-muslabi64 mipsel-unknown-linux-musl x86_64-unknown-linux-musl | xargs -n 1 rustup target add
$ echo aarch64-unknown-linux-musl arm-unknown-linux-musleabi mips-unknown-linux-musl mips64-unknown-linux-muslabi64 mips64el-unknown-linux-muslabi64 mipsel-unknown-linux-musl x86_64-unknown-linux-musl | xargs -n 1 cargo build --target
$ file target/*/debug/cargo-hello
target/aarch64-unknown-linux-musl/debug/cargo-hello:       ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, with debug_info, not stripped
target/arm-unknown-linux-musleabi/debug/cargo-hello:       ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), statically linked, with debug_info, not stripped
target/mips64el-unknown-linux-muslabi64/debug/cargo-hello: ELF 64-bit LSB executable, MIPS, MIPS64 rel2 version 1 (SYSV), statically linked, with debug_info, not stripped
target/mips64-unknown-linux-muslabi64/debug/cargo-hello:   ELF 64-bit MSB executable, MIPS, MIPS64 rel2 version 1 (SYSV), statically linked, with debug_info, not stripped
target/mipsel-unknown-linux-musl/debug/cargo-hello:        ELF 32-bit LSB pie executable, MIPS, MIPS32 rel2 version 1 (SYSV), dynamically linked, interpreter /lib/ld-musl-mipsel.so.1, with debug_info, not stripped
target/mips-unknown-linux-musl/debug/cargo-hello:          ELF 32-bit MSB pie executable, MIPS, MIPS32 rel2 version 1 (SYSV), dynamically linked, interpreter /lib/ld-musl-mips.so.1, with debug_info, not stripped
target/x86_64-unknown-linux-musl/debug/cargo-hello:        ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, with debug_info, not stripped

Notes

Output of cargo version: cargo 1.49.0 (d00d64df9 2020-12-05)

[Darlelet]

Seems that x86_64-unknown-linux-musl is also affected (from your output).

I checked myself, still the case in cargo 1.52.0 (69767412a 2021-04-21)

1.41.0 and earlier used to work just fine:

• testbinstatic: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), statically linked, with debug info, not stripped -> OK
• testbindynamic: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib/ld64.so.1, with debug info, not stripped -> OK

1.52.0:

• testbinstatic: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, with debug_info, not stripped -> NOK
• testbindynamic: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, with debug_info, not stripped -> NOK

The real issue there is that for expected static binaries we end up with dynamically linked bin, and for expected dynamic binaries: no linking is done to the default interpreter.
Trying to run it on the target system will make the program crash (because of missing interpreter initialization)

I'm forced to revert to cargo v1.41 to make my build system (X86_64 cross compile) functional.

[jonas-schievink]

cc rust-lang/compiler-team#422, which suggests that these targets behave correctly

[zengming00]

I use this configuration and it works

[target.mips-unknown-linux-musl]
linker = "mips-linux-musl-gcc"
rustflags = ["-C", "target-feature=+crt-static", "-C", "link-arg=-s"]

[abcfy2]

I use this configuration and it works

[target.mips-unknown-linux-musl]
linker = "mips-linux-musl-gcc"
rustflags = ["-C", "target-feature=+crt-static", "-C", "link-arg=-s"]

I think this feature should enable by default. https://doc.rust-lang.org/edition-guide/rust-2018/platform-and-target-support/musl-support-for-fully-static-binaries.html As cargo official blog said, musl support for fully static binaries.

[workingjubilee]

Unfortunately, we have decided that was the wrong default. You may still enable this feature on purpose, and we do support that and will continue to support that. See here:

• Update the existing musl targets to be dynamically linked. compiler-team#422