[debugger] Add ffx debug crash

This command enables ProcessLimbo and runs the debugger, expecting
something to crash in the near future. When the debugging session
eventually ends, ProcessLimbo is disabled again.

Change-Id: Icbdadcbe24b27ba2bfa2c681af6de5272b08167a
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/965623
Reviewed-by: Adam Barth <[email protected]>
Commit-Queue: Jacob Rutherford <[email protected]>
Reviewed-by: Clayton Wilkinson <[email protected]>

src/developer/ffx/plugins/debug/BUILD.gn

@@ -12,6 +12,7 @@ ffx_plugin("ffx_debug_plugin") {
   plugin_deps = [
     "connect:ffx_debug_connect",
     "core:ffx_debug_core",
+    "crash:ffx_debug_crash",
     "fidlcat:ffx_debug_fidlcat",
     "limbo:ffx_debug_limbo",
     "symbol-index:ffx_debug_symbol_index",

src/developer/ffx/plugins/debug/crash/BUILD.gn

@@ -0,0 +1,22 @@
+# Copyright 2023 The Fuchsia Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//src/developer/ffx/build/ffx_plugin.gni")
+
+ffx_plugin("ffx_debug_crash") {
+  version = "0.1.0"
+  edition = "2021"
+
+  args_sources = [ "src/args.rs" ]
+  sources = [ "src/lib.rs" ]
+
+  deps = [
+    "//sdk/fidl/fuchsia.debugger:fuchsia.debugger_rust",
+    "//sdk/fidl/fuchsia.exception:fuchsia.exception_rust",
+    "//src/developer/debug/ffx_zxdb",
+    "//src/developer/ffx/lib/fho:lib",
+    "//third_party/rust_crates:anyhow",
+    "//third_party/rust_crates:async-trait",
+  ]
+}

src/developer/ffx/plugins/debug/crash/src/args.rs

@@ -0,0 +1,11 @@
+// Copyright 2023 The Fuchsia Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+use argh::{ArgsInfo, FromArgs};
+use ffx_core::ffx_command;
+
+#[ffx_command()]
+#[derive(ArgsInfo, FromArgs, PartialEq, Debug)]
+#[argh(subcommand, name = "crash", description = "catch a crashing process on the target")]
+pub struct CrashCommand {}

src/developer/ffx/plugins/debug/crash/src/lib.rs

@@ -0,0 +1,51 @@
+// Copyright 2023 The Fuchsia Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+use anyhow::Result;
+use async_trait::async_trait;
+use ffx_debug_crash_args::CrashCommand;
+use ffx_zxdb::Debugger;
+use fho::{moniker, FfxMain, FfxTool, SimpleWriter};
+use fidl_fuchsia_debugger as fdebugger;
+use fidl_fuchsia_exception::ProcessLimboProxy;
+
+#[derive(FfxTool)]
+pub struct CrashTool {
+    #[command]
+    _cmd: CrashCommand,
+    #[with(moniker("/core/exceptions"))]
+    limbo_proxy: ProcessLimboProxy,
+    #[with(moniker("/core/debugger"))]
+    launcher_proxy: fdebugger::LauncherProxy,
+}
+
+fho::embedded_plugin!(CrashTool);
+
+#[async_trait(?Send)]
+impl FfxMain for CrashTool {
+    type Writer = SimpleWriter;
+
+    async fn main(self, mut _writer: Self::Writer) -> fho::Result<()> {
+        crash_tool_impl(self.limbo_proxy, self.launcher_proxy).await?;
+        Ok(())
+    }
+}
+
+async fn run_debugger(launcher_proxy: fdebugger::LauncherProxy) -> Result<()> {
+    let mut debugger = Debugger::launch(launcher_proxy).await?;
+    debugger.command.push_str("--auto-attach-limbo");
+    debugger.run().await
+}
+
+async fn crash_tool_impl(
+    limbo_proxy: ProcessLimboProxy,
+    launcher_proxy: fdebugger::LauncherProxy,
+) -> Result<()> {
+    limbo_proxy.set_active(true).await?;
+    let run_result = run_debugger(launcher_proxy).await;
+    limbo_proxy.set_active(false).await?;
+
+    run_result?;
+    Ok(())
+}

src/developer/ffx/tests/cli-goldens/goldens/debug_filelist.txt

@@ -1,6 +1,7 @@
 ffx/debug.golden
 ffx/debug/connect.golden
 ffx/debug/core.golden
+ffx/debug/crash.golden
 ffx/debug/fidl.golden
 ffx/debug/limbo.golden
 ffx/debug/limbo/disable.golden

src/developer/ffx/tests/cli-goldens/goldens/ffx/debug/crash.golden

@@ -0,0 +1,19 @@
+{
+  "name": "crash",
+  "description": "catch a crashing process on the target",
+  "examples": [],
+  "flags": [
+    {
+      "kind": "Switch",
+      "optionality": "optional",
+      "long": "--help",
+      "short": null,
+      "description": "display usage information",
+      "hidden": false
+    }
+  ],
+  "notes": [],
+  "commands": [],
+  "positionals": [],
+  "error_codes": []
+}