fix pi-lens warnings: unwraps, shell SC2046, dup code (fmtbuf/scripts/hexdump/cat/ahci/pci)

- memory.rs: self-test Layout::from_size_align no longer panics — the
  test fails cleanly on an invalid layout
- fat.rs: v() no longer unwraps the active-volume slot — invariant
  violation logs + halts instead of panicking mid-disk-io
- strbuf: shared FmtBuf replaces the duplicated PanicBuf/FmtBuf
  (main.rs + sched.rs)
- test-disk.sh: SC2046 — conditional --fresh arg no longer relies on
  word splitting
- scripts: boot.sh/boot-image.sh share lib-boot-args.sh (dup args loop)
- shell: cat/hexdump stdin pairs unified with Option<&str> marker;
  hexdump format_row folded into format_partial
- ahci: read/write_sectors unified behind dma_sectors
- pci: config_read/write share config_addr

1 files changed, 38 insertions, 0 deletions

diff --git a/scripts/lib-boot-args.sh b/scripts/lib-boot-args.sh
new file mode 100644
index 0000000..ec97500
--- /dev/null
+++ b/scripts/lib-boot-args.sh
@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+#
+# scripts/lib-boot-args.sh — shared CLI parsing for the QEMU boot scripts.
+# Sourced, not executed.  The caller sets default values for GUI/DEBUG/
+# MEM/SMP first, then calls `parse_boot_args "$@"`.  A caller with extra
+# flags defines its own `handle_arg()` to intercept them before the
+# shared cases run (unknown args still fail loudly).
+set -euo pipefail
+
+parse_boot_args() {
+        while [ $# -gt 0 ]; do
+                case "$1" in
+                --gui | -g) GUI="-vga std" ;;
+                --debug | -d) DEBUG="-s -S" ;;
+                --mem)
+                        shift
+                        MEM="$1"
+                        ;;
+                --smp)
+                        shift
+                        SMP="$1"
+                        ;;
+                --help | -h)
+                        head -20 "$0" | grep "^#" | sed 's/^# //'
+                        exit 0
+                        ;;
+                *) handle_arg "$1" ;;
+                esac
+                shift
+        done
+}
+
+# Default: no extra flags.  A script with more defines its own before
+# calling parse_boot_args.
+handle_arg() {
+        echo "unknown: $1"
+        exit 1
+}