Add basic forking coverage support

Cargo.toml

@@ -20,6 +20,7 @@ cargo_metadata = { version = "0.18.0", optional = true }
 clap = { version = "4.4.6", features = ["cargo", "derive", "env"], optional = true }
 console = { version = "0.15.7", optional = true }
 env_logger = { version = "0.10.0", optional = true }
+fork = { version = "0.1.22", optional = true }
 glob = { version = "0.3.1", optional = true }
 # We use our own fork of honggfuzz to use the tool's latest release
 # https://github.com/rust-fuzz/honggfuzz-rs/pull/85
@@ -49,3 +50,4 @@ cli = [
     "time-humanize",
     "cargo_metadata",
 ]
+coverage = ["fork", "libc"]

examples/arbitrary/Cargo.toml

@@ -5,5 +5,5 @@ edition = "2021"
 publish = false
 
 [dependencies]
-ziggy = { path = "../../", default-features = false }
+ziggy = { path = "../../", features = ["coverage"], default-features = false }
 arbitrary = { version = "1", features= ["derive"] }

src/bin/cargo-ziggy/coverage.rs

@@ -24,7 +24,11 @@ impl Cover {
 
         // We build the runner with the appropriate flags for coverage
         process::Command::new(cargo)
-            .args(["rustc", "--target-dir=target/coverage"])
+            .args([
+                "rustc",
+                "--target-dir=target/coverage",
+                "--features=ziggy/coverage",
+            ])
             .env("RUSTFLAGS", coverage_rustflags)
             .env("RUSTDOCFLAGS", "-Cpanic=unwind")
             .env("CARGO_INCREMENTAL", "0")
@@ -56,22 +60,12 @@ impl Cover {
 
         info!("Corpus directory is {}", shared_corpus.display());
 
-        // We run the target against the corpus
-        shared_corpus.canonicalize()?.read_dir()?.for_each(|item| {
-            let item = item.unwrap();
-            let item_path = item.path();
-
-            let result = process::Command::new(format!("./target/coverage/debug/{}", &self.target))
-                .args([item_path.as_os_str()])
-                .spawn()
-                .unwrap()
-                .wait_with_output()
-                .unwrap();
-
-            if !result.status.success() {
-                eprintln!("Coverage crashed on {}, continuing.", item_path.display())
-            }
-        });
+        let _ = process::Command::new(format!("./target/coverage/debug/{}", &self.target))
+            .arg(format!("{}", shared_corpus.display()))
+            .spawn()
+            .unwrap()
+            .wait_with_output()
+            .unwrap();
 
         let source_or_workspace_root = match &self.source {
             Some(s) => s.display().to_string(),