automatically patch binaries for nixos

src/error.rs

@@ -15,6 +15,8 @@ pub enum SolcVmError {
     ChecksumMismatch(String),
     #[error("Install step for solc version {0} timed out after {1} seconds")]
     Timeout(String, u64),
+    #[error("Unable to patch solc binary for nixos. stdout: {0}. stderr: {1}")]
+    CouldNotPatchForNixOs(String, String),
     #[error(transparent)]
     IoError(#[from] std::io::Error),
     #[error(transparent)]

src/lib.rs

@@ -1,12 +1,13 @@
 use once_cell::sync::Lazy;
-use semver::Version;
+use semver::{Version, VersionReq};
 use sha2::Digest;
 
 use std::{
     ffi::OsString,
     fs,
     io::{Cursor, Write},
     path::PathBuf,
+    process::Command,
 };
 
 use std::time::Duration;
@@ -43,6 +44,9 @@ pub static SVM_HOME: Lazy<PathBuf> = Lazy::new(|| {
 /// The timeout to use for requests to the source
 const REQUEST_TIMEOUT: Duration = Duration::from_secs(60);
 
+/// Version beyond which solc binaries are not fully static, hence need to be patched for NixOS.
+static NIXOS_PATCH_REQ: Lazy<VersionReq> = Lazy::new(|| VersionReq::parse(">=0.8.0").unwrap());
+
 // Installer type that copies binary data to the appropriate solc binary file:
 // 1. create target file to copy binary data
 // 2. copy data
@@ -68,7 +72,33 @@ impl Installer {
         let mut content = Cursor::new(&self.binbytes);
         std::io::copy(&mut content, &mut f)?;
 
-        Ok(solc_path)
+        if platform::is_nixos() && NIXOS_PATCH_REQ.matches(&self.version) {
+            patch_for_nixos(solc_path)
+        } else {
+            Ok(solc_path)
+        }
+    }
+}
+
+/// Patch the given binary to use the dynamic linker provided by nixos
+pub fn patch_for_nixos(bin: PathBuf) -> Result<PathBuf, SolcVmError> {
+    let output = Command::new("nix-shell")
+        .arg("-p")
+        .arg("patchelf")
+        .arg("--run")
+        .arg(format!(
+            "patchelf --set-interpreter \"$(cat $NIX_CC/nix-support/dynamic-linker)\" {}",
+            bin.display()
+        ))
+        .output()
+        .expect("Failed to execute command");
+
+    match output.status.success() {
+        true => Ok(bin),
+        false => Err(SolcVmError::CouldNotPatchForNixOs(
+            String::from_utf8(output.stdout).expect("Found invalid UTF-8 when parsing stdout"),
+            String::from_utf8(output.stderr).expect("Found invalid UTF-8 when parsing stderr"),
+        )),
     }
 }
 

src/platform.rs

@@ -42,6 +42,10 @@ impl FromStr for Platform {
     }
 }
 
+pub fn is_nixos() -> bool {
+    std::path::Path::new("/etc/NIXOS").exists()
+}
+
 /// Read the current machine's platform.
 pub fn platform() -> Platform {
     match (env::consts::OS, env::consts::ARCH) {