Dump IPC messages to serial port #2 as a pcapng file

src/interrupts.rs

@@ -1,8 +1,8 @@
 use crate::{
-    bootinfo::BOOTINFO, dbg, print, println, tasking::SleepReason, virtual_memory::{ASpaceMutex, AddressSpace, ACTIVE_SPACE, KERNEL_SPACE}, TASKING
+    bootinfo::BOOTINFO, print, println, serial::SECOND_PORT, tasking::SleepReason, virtual_memory::{ASpaceMutex, AddressSpace, ACTIVE_SPACE, KERNEL_SPACE}, TASKING
 };
 use alloc::{boxed::Box, vec::Vec};
-use core::{arch::asm, ptr::{addr_of, slice_from_raw_parts_mut}, slice, str};
+use core::{arch::asm, ptr::addr_of, slice, str};
 use hashbrown::HashMap;
 use pic8259::ChainedPics;
 use spin::{Lazy, Mutex, RwLock};
@@ -318,9 +318,24 @@ extern "C" fn syscall_handler() {
                 let mut tasking = TASKING.lock();
                 if let Some(_queue) = tasking.message_queue_mut(pid) {
                     let len = regs.rsi as usize;
+                    let trunc_len = usize::min(len, 4096) as u32;
+                    let padding = if (trunc_len % 4) != 0 { 4 - (trunc_len % 4) } else { 0 };
+                    let padded_len = trunc_len + padding;
+                    SECOND_PORT.write_u32s(&[
+                        0x3,                      // SPB type
+                        padded_len + 8 + (4 * 4), // Total block length
+                        (len as u32) + 8,         // Packet length
+                    ]);
+                    SECOND_PORT.write_bytes(&pid.to_ne_bytes());
+                    SECOND_PORT.write_bytes(&buffer[0..trunc_len as usize]);
+                    for _ in 0..padding {
+                        SECOND_PORT.write_bytes(&[0]);
+                    }
+                    SECOND_PORT.write_u32s(&[
+                        padded_len + 8 + (4 * 4), // Total block length
+                    ]);
                     let buffer = Box::into_raw(buffer);
-                    let new_buffer_key =
-                        tasking.proc_data_buffers_mut(pid).insert(buffer);
+                    let new_buffer_key = tasking.proc_data_buffers_mut(pid).insert(buffer);
                     let queue = tasking.message_queue_mut(pid).unwrap();
                     queue.push((new_buffer_key, len));
                     if tasking.proc_sleeping(pid) == Some(SleepReason::WaitingForIPC) {

src/main.rs

@@ -27,6 +27,7 @@ use core::{slice, usize};
 
 use bootinfo::BOOTINFO;
 use elf::{abi::{PT_DYNAMIC, PT_GNU_EH_FRAME, PT_GNU_RELRO, PT_GNU_STACK, PT_LOAD, PT_NULL, PT_PHDR, R_X86_64_RELATIVE, SHT_REL, SHT_RELA}, endian::AnyEndian, ElfBytes};
+use serial::SECOND_PORT;
 use tar_no_std::TarArchiveRef;
 use tasking::TASKING;
 use x86_64::{registers::rflags::{self, RFlags}, structures::paging::{Page, PageTableFlags}, VirtAddr};
@@ -118,6 +119,23 @@ pub fn main() {
             }
         }
     }
+
+    // Before starting init, write the pcapng section header + interface description to the second serial port
+    SECOND_PORT.write_u32s(&[
+        0x0A0D0D0A,  // SHB type
+        7 * 4,       // Total block length
+        0x1A2B3C4D,  // Byte order magic
+        0x0000_0001, // Version (1.0)
+        0xFFFFFFFF,  // Length upper (-1) across both
+        0xFFFFFFFF,  // Length lower
+        7 * 4,       // Total block length
+        0x1,         // IDB type
+        5 * 4,       // Total block length
+        147,         // Link type
+        4096 + 8,    // Packet length limit,
+        5 * 4,       // Total block length
+    ]);
+
     TASKING
         .lock()
         .new_process(

src/serial.rs

@@ -2,7 +2,7 @@ use core::{fmt, fmt::Write};
 use spin::{Lazy, Mutex};
 use uart_16550::SerialPort;
 
-pub static PORT: Lazy<Wrapper> = Lazy::new(|| {
+pub static FIRST_PORT: Lazy<Wrapper> = Lazy::new(|| {
     // SAFETY:
     // 0x3f8 is the defined address for the first serial port on x86_64,
     // so we know it is safe to use that as the port's base address.
@@ -11,6 +11,15 @@ pub static PORT: Lazy<Wrapper> = Lazy::new(|| {
     Wrapper(Mutex::new(port))
 });
 
+pub static SECOND_PORT: Lazy<Wrapper> = Lazy::new(|| {
+    // SAFETY:
+    // 0x2f8 is the defined address for the second serial port on x86_64,
+    // so we know it is safe to use that as the port's base address.
+    let mut port = unsafe { SerialPort::new(0x2f8) };
+    port.init();
+    Wrapper(Mutex::new(port))
+});
+
 pub struct Wrapper(Mutex<SerialPort>);
 impl fmt::Write for &Wrapper {
     fn write_str(&mut self, s: &str) -> fmt::Result {
@@ -18,6 +27,22 @@ impl fmt::Write for &Wrapper {
     }
 }
 
+impl Wrapper {
+    pub fn write_bytes(&self, bytes: &[u8]) {
+        let mut port = self.0.lock();
+        for byte in bytes {
+            port.send_raw(*byte);
+        }
+    }
+
+    pub fn write_u32s(&self, u32s: &[u32]) {
+        for elem in u32s {
+            let bytes = elem.to_ne_bytes();
+            self.write_bytes(&bytes);
+        }
+    }
+}
+
 #[macro_export]
 macro_rules! print {
     ($($arg:tt)*) => ($crate::serial::_print(format_args!($($arg)*)));
@@ -53,5 +78,5 @@ macro_rules! dbg {
 
 #[doc(hidden)]
 pub fn _print(args: fmt::Arguments) {
-    (&*PORT).write_fmt(args).unwrap();
+    (&*FIRST_PORT).write_fmt(args).unwrap();
 }