From 6baac54893bd7eb5eed7c94f67e7e500117d7e19 Mon Sep 17 00:00:00 2001
From: Alex Huszagh <ahuszagh@gmail.com>
Date: Sat, 4 Jun 2022 11:35:18 -0500
Subject: [PATCH] Fix docker detection.

Currently, docker detection fails under a few cases:
1. If `podman_docker` is installed, so the filename is docker but the
actual executable is podman. 2. If the executable has a suffix, such as `.exe` on Windows, because we check if the executable `ends_with(DOCKER)`.

The only reliable way to fix both these issues, IE, if the actual engine is docker and not an alias, and if the executable does not contain a suffix, is to query the container engine. This might not be ideal for performance reasons, but is the only reliable way to fix these issues.

Emulated docker will have an output of `Emulate Docker CLI using podman.`, while docker itself will have an output similar to `Docker version 20.10.16, build aa7e414`.

Closes #530.
Closes #538.
---
 src/docker.rs | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/src/docker.rs b/src/docker.rs
index 6f9085696..07c21d1d7 100644
--- a/src/docker.rs
+++ b/src/docker.rs
@@ -15,6 +15,17 @@ const CROSS_IMAGE: &str = "ghcr.io/cross-rs";
 const DOCKER: &str = "docker";
 const PODMAN: &str = "podman";
 
+// determine if the container engine is docker. this fixes issues with
+// any aliases (#530), and doesn't fail if an executable suffix exists.
+fn get_is_docker(ce: std::path::PathBuf, verbose: bool) -> Result<bool> {
+    let stdout = Command::new(ce)
+        .arg("--help")
+        .run_and_get_stdout(verbose)?
+        .to_lowercase();
+
+    Ok(stdout.contains("docker") && !stdout.contains("emulate"))
+}
+
 fn get_container_engine() -> Result<std::path::PathBuf, which::Error> {
     if let Ok(ce) = env::var("CROSS_CONTAINER_ENGINE") {
         which::which(ce)
@@ -126,6 +137,7 @@ pub fn run(
     let runner = config.runner(target)?;
 
     let mut docker = docker_command("run")?;
+    let is_docker = get_is_docker(get_container_engine().unwrap(), verbose)?;
 
     for ref var in config.env_passthrough(target)? {
         validate_env_var(var)?;
@@ -179,17 +191,15 @@ pub fn run(
     }
 
     // We need to specify the user for Docker, but not for Podman.
-    if let Ok(ce) = get_container_engine() {
-        if ce.ends_with(DOCKER) {
-            docker.args(&[
-                "--user",
-                &format!(
-                    "{}:{}",
-                    env::var("CROSS_CONTAINER_UID").unwrap_or_else(|_| id::user().to_string()),
-                    env::var("CROSS_CONTAINER_GID").unwrap_or_else(|_| id::group().to_string()),
-                ),
-            ]);
-        }
+    if is_docker {
+        docker.args(&[
+            "--user",
+            &format!(
+                "{}:{}",
+                env::var("CROSS_CONTAINER_UID").unwrap_or_else(|_| id::user().to_string()),
+                env::var("CROSS_CONTAINER_GID").unwrap_or_else(|_| id::group().to_string()),
+            ),
+        ]);
     }
 
     docker