Parse ramdisk tar file

Makefile

@@ -4,11 +4,12 @@ include build/make.help
 srctree := $(PWD)
 
 include platform/make.$(platform)
+include distrib/make.distrib
 
 kernel:
 	$(make) -C $(srctree)/kernel srctree=$(srctree) all
 
-clean: platform_clean
+clean: platform_clean distrib_clean
 	$(make) -C $(srctree)/kernel srctree=$(srctree) clean
 
 .hidden:

distrib/etc/file.txt

@@ -0,0 +1 @@
+Hello file

distrib/make.distrib

@@ -0,0 +1,8 @@
+
+distrib_prepare:
+	tar -cvf $(srctree)/out/ramdisk.tar -C $(srctree)/distrib .
+
+distrib_clean:
+	rm -f $(srctree)/out/ramdisk.tar
+
+.PHONY: distrib_prepare distrib_clean

kernel/libk/string.c

@@ -60,3 +60,16 @@ usize_t strlen(const char *str) {
   for (s = str; *s; ++s);
   return (s - str);
 }
+
+int memcmp(const void *s1, const void *s2, usize_t n) {
+  unsigned char *p = (unsigned char *)s1;
+  unsigned char *q = (unsigned char *)s2;
+
+  while (n--) {
+    if (*p != *q) {
+      return (int)*p - (int)*q;
+    }
+    p++, q++;
+  }
+  return 0;
+}

kernel/libk/string.h

@@ -36,6 +36,8 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 usize_t memset(void *dst, byte_t b, usize_t n);
 usize_t memcpy(void *dst, const void *src, usize_t n);
+int memcmp(const void *s1, const void *s2, usize_t n);
+
 void strncpy(char* dst, const char* src, usize_t n);
 usize_t strlen(const char *str);
 

kernel/make.src

@@ -7,3 +7,4 @@ include libk/make.src
 include sync/make.src
 include mm/make.src
 include irq/make.src
+include ramdisk/make.src

kernel/platform/i386_pc/boot/bootmain.c

@@ -43,6 +43,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <mm/bba.h>
 #include <mm/liballoc.h>
 #include <mm/mregmap.h>
+#include <ramdisk/tar.h>
 #include <config.h>
 
 extern byte_t __kernel_end;
@@ -94,9 +95,17 @@ static void mregmap_init1(void) {
   }
 }
 
-static void pmm_init1(void) {
+static void ramdisk_init(void) {
   struct multiboot *mb = multiboot_get();
 
+  /* TODO: for now we assert that the first module is the ramdisk */
+  struct multiboot_mod_list *module = (struct multiboot_mod_list *)((uptr_t)mb->mods_addr + VIRT_BASE);
+  uptr_t module_start = (uptr_t)module->mod_start + VIRT_BASE;
+  usize_t total = tar_parse(module_start);
+  dbgf("ramdisk: total=%zu\n", total);
+}
+
+static void pmm_init1(void) {
   struct mreg *avail_ram = mregmap_first_avail();
 
   usize_t usable_ram_bytes = avail_ram->size;
@@ -135,6 +144,7 @@ void bootmain(void *mbootptr) {
   pmm_init1();
   bba_init();
   mm_init();
+  ramdisk_init();
   pit_init();
    
   __asm__ volatile("sti");

kernel/ramdisk/.gitignore

@@ -0,0 +1 @@
+*.o

kernel/ramdisk/make.src

@@ -0,0 +1,5 @@
+dir_tar1 := $(patsubst %/,%,$(dir $(abspath $(lastword $(MAKEFILE_LIST)))))
+
+c_files += $(dir_tar1)/tar.c
+
+o_files += $(dir_tar1)/tar.o

kernel/ramdisk/tar.c

@@ -0,0 +1,68 @@
+/*
+Copyright 2025 Kamil Kowalczyk
+
+Redistribution and use in source and binary forms, with or
+without modification, are permitted provided that the following
+conditions are met:
+
+1. Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+“AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#include <libk/types.h>
+#include <ramdisk/tar.h>
+
+static struct tar_header *ramdisk_tar_headers[TAR_MAX];
+
+usize_t tar_get_size(const byte_t *input) {
+  usize_t size = 0;
+  usize_t j;
+  usize_t count = 1;
+
+  for (j = 11; j > 0; j--, count *= 8)
+    size += ((input[j - 1] - '0') * count);
+
+  return size;
+}
+
+usize_t tar_parse(uptr_t addr) {
+  usize_t i;
+
+  for (i = 0; ; i++) {
+    struct tar_header *header = (struct tar_header *)addr;
+
+    if (header->filename[i] == '\0')
+      break;
+
+    usize_t size = tar_get_size(header->size);
+
+    ramdisk_tar_headers[i] = header;
+
+    addr += ((size / 512) + 1) * 512;
+
+    if (size % 512)
+      addr += 512;
+  }
+
+  return i;
+}

kernel/ramdisk/tar.h

@@ -0,0 +1,53 @@
+/*
+Copyright 2025 Kamil Kowalczyk
+
+Redistribution and use in source and binary forms, with or
+without modification, are permitted provided that the following
+conditions are met:
+
+1. Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+“AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef _RAMDISK_TAR_H
+#define _RAMDISK_TAR_H
+
+#include <libk/types.h>
+
+#define TAR_MAX   64
+
+struct tar_header {
+  byte_t filename[100];
+  byte_t mode[8];
+  byte_t uid[8];
+  byte_t gid[8];
+  byte_t size[12];
+  byte_t mtime[12];
+  byte_t checksum[8];
+  byte_t typeflag[1];
+};
+
+usize_t tar_get_size(const byte_t *input);
+usize_t tar_parse(uptr_t addr);
+
+#endif // _RAMDISK_TAR_H

platform/i386_pc/bochsrc.txt

@@ -1,22 +1,28 @@
 # machine
 megs: 64
 cpu: model=pentium
+
 # roms
 romimage: file=/usr/share/bochs/BIOS-bochs-latest, options=fastboot
 vgaromimage: file=/usr/share/bochs/VGABIOS-lgpl-latest.bin
+
 # device config
 ata0: enabled=1
 ata0-master: type=cdrom, path=out/i386_pc/mop3.iso, status=inserted
 com1: enabled=1, mode=file, dev=bochs-com1.log
+
 # clock
 clock: sync=realtime
+
 # boot device
 boot: cdrom
+
 # logging
 error: action=report
 panic: action=report
 info: action=report
 debug: action=ignore
 log: bochs.log
+
 # display
 display_library: x

platform/i386_pc/grub.cfg

@@ -3,5 +3,6 @@ set default=0
 
 menuentry "mop3" {
   multiboot /boot/kernel.elf
+  module /boot/ramdisk.tar
   boot
 }

platform/make.i386_pc

@@ -1,6 +1,7 @@
 $(srctree)/out/i386_pc/mop3.iso: $(srctree)/out/kernel.elf
 	mkdir -p $(srctree)/out/i386_pc/tmp/iso/boot/grub
 	cp $(srctree)/out/kernel.elf $(srctree)/out/i386_pc/tmp/iso/boot
+	cp $(srctree)/out/ramdisk.tar $(srctree)/out/i386_pc/tmp/iso/boot
 	cp $(srctree)/platform/i386_pc/grub.cfg $(srctree)/out/i386_pc/tmp/iso/boot/grub
 	grub-mkrescue -o $(srctree)/out/i386_pc/mop3.iso $(srctree)/out/i386_pc/tmp/iso