Module bare_metal

Bare-metal main loop for post-ExitBootServices execution.

This module provides the complete end-to-end runner that:

1. Initializes the VirtIO-net driver using ASM layer
2. Creates the smoltcp interface and sockets
3. Runs the 5-phase main loop
4. Orchestrates ISO download and disk write
5. Writes manifest to disk for boot entry discovery

Reference

NETWORK_IMPL_GUIDE.md §6, §7

Structs

• BareMetalConfig
  Configuration for the bare-metal runner.
• RxToken
  RX token for smoltcp - uses a fixed-size buffer (no heap allocation). Maximum Ethernet frame size is 1514 bytes.
• SmoltcpAdapter
  Adapter bridging NetworkDriver to smoltcp Device trait.
• TxToken
  TX token for smoltcp - uses a fixed-size stack buffer (no heap allocation).

Enums

• RunResult
  Run result.

Constants

• DISK_WRITE_BUFFER_SIZE 🔒
  Size of write buffer: 64KB = 128 sectors (optimal for VirtIO-blk)
• SECTORS_PER_WRITE 🔒
  Number of sectors per write operation
• SERIAL_PORT 🔒
  Serial port base address (COM1).

Statics

• ACTUAL_START_SECTOR 🔒
  Actual start sector (after finding free space)
• DISK_NEXT_REQUEST_ID 🔒
  Next request ID for block driver
• DISK_NEXT_SECTOR 🔒
  Next sector to write to
• DISK_TOTAL_BYTES 🔒
  Total bytes written to disk
• DISK_WRITE_BUFFER 🔒
  Static buffer for accumulating data before disk write
• DISK_WRITE_BUFFER_FILL 🔒
  Current fill level of write buffer
• MANIFEST_BUFFER 🔒
  Static buffer for manifest serialization (1 sector = 512 bytes, but manifest can be up to ~1KB, so use 2 sectors).
• POLL_DEPTH 🔒
  Static flag to detect reentrancy in polling loop. If this is > 1 during a poll, we have a bug.

Functions

• bare_metal_main^⚠
  Main bare-metal entry point.
• buffer_disk_write 🔒 ^⚠
  Add data to the disk write buffer. Automatically flushes when buffer is full. Returns the number of bytes consumed from the input.
• contains_ignore_case 🔒
  Case-insensitive contains for ASCII strings (no heap allocation).
• create_iso_partition 🔒 ^⚠
  Create a GPT partition for ISO data storage.
• enter_poll 🔒
  Increment poll depth, panic if already polling.
• exit_poll 🔒
  Decrement poll depth.
• finalize_manifest 🔒 ^⚠
  Create and write a completed ISO manifest to disk.
• finalize_manifest_fat32 🔒 ^⚠
  Write manifest to FAT32 ESP filesystem.
• finalize_manifest_raw 🔒 ^⚠
  Write manifest to raw disk sector (legacy method).
• find_header_end 🔒
  Find the end of HTTP headers (\r\n\r\n). Returns the position of the first \r in \r\n\r\n.
• flush_disk_buffer 🔒 ^⚠
  Flush the disk write buffer to the block device.
• flush_remaining_disk_buffer 🔒 ^⚠
  Flush any remaining data in the buffer (for end of download).
• format_http_get 🔒
  Format an HTTP GET request into a static buffer. Returns the number of bytes written, or None if buffer too small.
• parse_ipv4 🔒
  Parse IPv4 address from string without allocation. Format: “a.b.c.d” where a,b,c,d are 0-255.
• parse_u8 🔒
  Parse a u8 from a string without allocation.
• parse_u16 🔒
  Parse a u16 from a string without allocation.
• parse_usize 🔒
  Parse usize from string without allocation.
• print_ipv4
  Print an IPv4 address (e.g., “10.0.2.15”).
• run_full_download^⚠
  Full integrated main loop with real state machines.
• serial_print
  Write string to serial port.
• serial_print_decimal
  Print a decimal number.
• serial_print_hex
  Print hex number.
• serial_println
  Write string with newline.
• serial_write_byte 🔒 ^⚠
  Write a byte to serial port.
• starts_with_ignore_case 🔒
  Case-insensitive starts_with for ASCII strings (no heap allocation).
• tsc_to_instant 🔒
  Convert TSC ticks to smoltcp Instant.
• write_manifest_to_disk 🔒 ^⚠
  Write an ISO manifest to disk at the specified sector.