argv[0] in WASIX subprocesses should resolve to the atom rather than the full command

[Arshia001]

No description provided.

[Copilot]

Pull request overview

Updates WASIX command execution so that argv[0] in spawned processes resolves to the underlying atom (via a canonical atom VFS path) instead of the command wrapper, preventing command metadata (notably main_args) from being re-applied on re-exec.

Changes:

• Add a new WASM test that re-execs via argv[0] and asserts main_args are not re-injected.
• Inject per-command atoms into a dedicated /bin/.__atoms/... path and prefer that path for argv[0]/exec_name.
• Add BinaryPackageCommand::atom_vfs_path() to compute the canonical atom VFS path.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
lib/wasix/tests/wasm_tests/proc_exec_command_argv0/main.c	New C harness that re-execs via argv[0] and validates arg behavior.
lib/wasix/tests/wasm_tests/proc_exec_command_argv0/build.sh	Build script for the new WASM test binary.
lib/wasix/tests/wasm_tests/proc_exec_command_argv0.rs	New Rust integration test building a package with distinct command/atom names and main_args.
lib/wasix/tests/wasm_tests/mod.rs	Registers the new test module.
lib/wasix/src/state/env.rs	Injects atoms under /bin/.__atoms/... and prefers the atom VFS path for argv[0].
lib/wasix/src/runners/wasi.rs	Prefers atom VFS path for exec name when no explicit annotation exec_name is set.
lib/wasix/src/bin_factory/binary_package.rs	Adds atom_vfs_path() helper for canonical atom VFS path derivation.

[Copilot]

Overwriting argv[0] with cmd.atom_vfs_path() assumes the atom has been injected at that path. If atom injection is best-effort (or can fail), consider falling back to the previous exec_name/command name behavior unless the atom path is known to exist, to avoid breaking programs that re-exec themselves via argv[0].

Suggested change

	// Prefer an explicit exec_name from the annotation; otherwise use
	// the atom's canonical VFS path (e.g.
	// "/bin/.__atoms/wasmer/php/php") so that re-exec via argv[0] finds
	// the raw wasm without triggering prepare_spawn again.
	let argv0 = exec_name.or_else(|| cmd.atom_vfs_path());
	if let Some(argv0) = argv0 {
	// Only replace argv[0] when the package explicitly provides an
	// exec_name. Falling back to the atom VFS path here is unsafe
	// unless injection at that path is known to have succeeded, and a
	// missing path can break programs that re-exec themselves via
	// argv[0].
	if let Some(argv0) = exec_name {