feat(minvmd): scaffold crate with libkrun FFI wrappers and smoke test - #237

crates/minvmd/src/krun/ctx.rs (1)

93-106: ⚡ Quick win

Prefer Option combinators over reconstructive match blocks.

The envp_cstrs, initramfs_cstr, and cmdline_cstr conversions can be expressed more idiomatically with combinators, which keeps the flow tighter and aligns with repo Rust style.

Refactor sketch

-        let envp_cstrs: Option<Vec<CString>> = match envp {
-            Some(entries) => Some(cstrings_from_strs(entries, "envp")?),
-            None => None,
-        };
+        let envp_cstrs = envp
+            .map(|entries| cstrings_from_strs(entries, "envp"))
+            .transpose()?;
...
-        let initramfs_cstr = match initramfs {
-            Some(p) => Some(cstring_from_path(p.as_ref(), "initramfs")?),
-            None => None,
-        };
-        let cmdline_cstr = match cmdline {
-            Some(s) => Some(cstring_from_str(s, "cmdline")?),
-            None => None,
-        };
+        let initramfs_cstr = initramfs
+            .map(|p| cstring_from_path(p.as_ref(), "initramfs"))
+            .transpose()?;
+        let cmdline_cstr = cmdline
+            .map(|s| cstring_from_str(s, "cmdline"))
+            .transpose()?;

As per coding guidelines, "Use combinators on Option/Result (map, and_then, ok_or, unwrap_or_else, map_err) instead of match expressions that reconstruct the same enum".

Also applies to: 148-155

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/minvmd/src/krun/ctx.rs` around lines 93 - 106, The envp conversion
reconstructs Option with match; replace it with Option combinators: build
envp_cstrs by using envp.map(|entries| cstrings_from_strs(entries, "envp")?) (or
map_then/and_then to propagate Result), and then create (envp_ptrs, envp_ptr)
with envp_cstrs.as_ref().map(|cstrs| { let mut ptrs = cstrs.iter().map(|c|
c.as_ptr()).collect::<Vec<_>>(); ptrs.push(ptr::null()); (ptrs, ptrs.as_ptr() as
*const *const c_char) }).unwrap_or((Vec::new(), ptr::null())); apply the same
pattern to initramfs_cstr and cmdline_cstr conversions to remove reconstructive
match blocks while preserving the existing symbols envp_cstrs,
cstrings_from_strs, envp_ptrs, and envp_ptr.

crates/minvmd/src/krun/mod.rs (1)

17-18: ⚡ Quick win

Narrow module visibility to avoid exposing internal layering details.

Line 17 and Line 18 currently publish internals (ctx, raw) as part of the crate API. Prefer keeping modules private (or pub(crate)) and exposing only curated items like Context via re-export.

♻️ Suggested visibility tightening

-pub mod ctx;
-pub mod raw;
+mod ctx;
+pub(crate) mod raw;
 
 pub use ctx::Context;

As per coding guidelines, "Make items private by default; widen to pub(crate) before pub; curate the public API via pub use at the crate root".

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/minvmd/src/krun/mod.rs` around lines 17 - 18, The crate currently
exposes internal modules `ctx` and `raw` publicly; change their visibility to
private (or `pub(crate)`) so internals aren't part of the public API, then
re-export only the curated public types (e.g., `Context`) from the crate root
using `pub use` (reference the `ctx` module's `Context` type and any other
public-facing symbols you intend to expose) so consumers see only the intended
API surface while implementation details in `ctx` and `raw` remain hidden.

crates/minvmd/src/krun/raw.rs (1)

46-47: ⚡ Quick win

Stale reference: check_backend is no longer on VmError.

This SAFETY note still points at crate::error::VmError::check_backend, but the helper was moved into this module as a free function. Update the reference to avoid misleading future contributors.

📝 Proposed doc fix

-// - Return values are i32: zero or positive on success, negative errno on
-//   failure. [`crate::error::VmError::check_backend`] translates these.
+// - Return values are i32: zero or positive on success, negative errno on
+//   failure. [`check_backend`] translates these.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@crates/minvmd/src/krun/raw.rs` around lines 46 - 47, The SAFETY doc comment
refers to the moved helper as crate::error::VmError::check_backend, which is
stale; update the reference to the new free function name in this module
(check_backend) or fully qualify it (crate::krun::raw::check_backend) in the
comment so readers can find the helper; adjust the SAFETY note text to mention
check_backend as a free function rather than a VmError method.