[BUG] No such file or directory

[rakanalh]

Bug Report

I am using Nixos. However, for the purpose of being able to build sovereign-sdk, and because this crate depends on rustup being present (nixos can install rust with nix-shell without rustup), i installed rustup and have a rusup installation of the rust toolchain.
Now, i have executed:

cargo binstall --force -y cargo-risczero && cargo risczero install

The latter step AFAIU would install a custom toolchain specifically for risc0. However, when trying to build the demo rollup in sovereign-sdk:

cargo build --bins
   Compiling sov-modules-api v0.3.0 (/home/rakan/Code/Rust/sovereign-sdk/module-system/sov-modules-api)
   Compiling risc0-circuit-recursion v0.19.1
   Compiling risc0 v0.3.0 (/home/rakan/Code/Rust/sovereign-sdk/examples/demo-rollup/provers/risc0)
error: failed to run custom build command for `risc0-circuit-recursion v0.19.1`

Caused by:
  process didn't exit successfully: `/home/rakan/Code/Rust/sovereign-sdk/target/debug/build/risc0-circuit-recursion-ed6dd89a50b932ab/build-script-build` (exit status: 101)
  --- stderr
  Downloading https://github.com/risc0/risc0/raw/505295b963c97db2afffe58f4b0cb4721e396b90/risc0/circuit/recursion/src/recursion_zkr.zip
  thread 'main' panicked at /home/rakan/.cargo/registry/src/index.crates.io-6f17d22bba15001f/risc0-circuit-recursion-0.19.1/build.rs:72:51:
  called `Result::unwrap()` on an `Err` value: Download(/home/rakan/Code/Rust/sovereign-sdk/target/debug/build/risc0-circuit-recursion-5e3c417694435cf2/out/recursion_zkr.zip: (verification: unverified):
  )
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...
sov-demo-prover-guest-celestia: Starting build for riscv32im-risc0-zkvm-elfild)
sov-demo-prover-guest-celestia: error: could not execute process `/home/rakan/.rustup/toolchains/risc0/bin/rustc -vV` (never executed)
sov-demo-prover-guest-celestia:
sov-demo-prover-guest-celestia: Caused by:
sov-demo-prover-guest-celestia:   No such file or directory (os error 2)
error: failed to run custom build command for `risc0 v0.3.0 (/home/rakan/Code/Rust/sovereign-sdk/examples/demo-rollup/provers/risc0)`

Caused by:
  process didn't exit successfully: `/home/rakan/Code/Rust/sovereign-sdk/target/debug/build/risc0-a19e980724198905/build-script-build` (exit status: 101)
  --- stdout
  Building guest package risc0.sov-demo-prover-guest-celestia
  cargo:rerun-if-env-changed=RISC0_SKIP_BUILD
  Using rustc: /home/rakan/.rustup/toolchains/risc0/bin/rustc
  cargo:rerun-if-env-changed=RISC0_RUST_SRC
  Building guest package: cargo build --target riscv32im-risc0-zkvm-elf
  cargo:rerun-if-env-changed=RISC0_BUILD_DEBUG

Which means that i do have a rustc compiler downloaded with cargo riskzero install.

➜ rustup toolchain list
stable-x86_64-unknown-linux-gnu (override)
risc0 (default)

The rustc binary, however, does not seem to execute:

➜ ls -l /home/rakan/.rustup/toolchains/risc0/bin/rustc
.rwxr-xr-x 17k rakan  8 Feb 22:17 /home/rakan/.rustup/toolchains/risc0/bin/rustc

➜ /home/rakan/.rustup/toolchains/risc0/bin/rustc
zsh: no such file or directory: /home/rakan/.rustup/toolchains/risc0/bin/rustc

Steps to Reproduce

1. Using nixos, install rustup globally
2. git clone https://github.com/Sovereign-Labs/sovereign-sdk.git
3. cd examples/demo-rollup
4. cargo build --bins (as in the readme)

Expected behavior

The rustc binary downloaded should run as expected.

Your Environment

• risc0-zkvm version:
• Rust version:

➜ rustc --version
rustc 1.76.0 (07dca489a 2024-02-04)

• Platform/OS:

Linux nixos 6.1.81 #1-NixOS SMP PREEMPT_DYNAMIC Wed Mar  6 14:45:20 UTC 2024 x86_64 GNU/Linux

Additional context

[linear]

ZKVM-380 [BUG] No such file or directory

[rakanalh]

According to NixOS/nixpkgs#107375 (comment),

This is because NixOS avoids global state and therefore doesn't install the binary interpreter ld-linux.so and generally libraries to the default locations as on other Linux distribution. This means that dynamically linked binaries built elsewhere won't run out of the box

Looking into https://github.com/risc0/risc0/tree/main/risc0/cargo-risczero, apparently i can use the cargo risczero build-toolchain to build the toolchain for my host which is what i am currently doing.

However, my question is why do need a specific toolchain that is downloaded from this repo and not downloadable from rustup in this case?

[rakanalh]

build-toolchain subcommand worked fine. Closing the issue.