Added initrd driver

kernel/drivers/Makefile

@@ -1,5 +1,5 @@
 OBJS = tty.o gdt.o idt.o isr.o timer.o keyboard.o  \
-		fs.o cpuid.o
+		fs.o cpuid.o initrd.o
 
 CC = i686-elf-gcc # cross-compiler
 CFLAGS = -m32 -fno-stack-protector -DDEFAULT_USER=root -DDEFAULT_HOSTNAME=vulcan -ffreestanding -Wall -Wextra -Werror -g -c

kernel/drivers/initrd.c

@@ -1,26 +1,79 @@
 #include "initrd.h"
 
+// Private API to IO operations on dir and files
+static uint32_t initrd_read(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
+static struct dirent *initrd_readdir(fs_node_t *node, uint32_t index);
+static fs_node_t *initrd_finddir(fs_node_t *node, uint8_t *name);
+
 // Declare various things
 initrd_header_t *initrd_header; // Header
-initrd_file_header_t *file_header; // List of headers
+initrd_file_header_t *file_headers; // List of headers
 fs_node_t *initrd_root; // Directory root node
 fs_node_t *initrd_dev; // Directory dev node(/dev)
 fs_node_t *root_nodes; // List of file nodes
-uint32_t nroot_nodes;
+uint32_t nroot_nodes; // Number of file nodes
 
 struct dirent dirent;
 
 fs_node_t *init_ramdisk(uint32_t multiboot_location) {
     // Initialize main and file headers
     initrd_header = (initrd_header_t*)multiboot_location;
-    file_header = (initrd_file_header_t*)(multiboot_location+sizeof(initrd_header_t));
+    file_headers = (initrd_file_header_t*)(multiboot_location+sizeof(initrd_header_t));
     // Initialize root directory
-    initrd_root = (fs_node_t*)
+    initrd_root = (fs_node_t*)kmalloc(sizeof(fs_node_t));
+    strcpy(initrd_root->name, "initrd");
+    initrd_root->mask = initrd_root->uid = initrd_root->gid = initrd_root->inode = initrd_root->length = 0;
+    initrd_root->flags = FS_DIRECTORY;
+    initrd_root->read = 0;
+    initrd_root->write = 0;
+    initrd_root->open = 0;
+    initrd_root->close = 0;
+    initrd_root->readdir = &initrd_readdir;
+    initrd_root->finddir = &initrd_finddir;
+    initrd_root->ptr = 0;
+    initrd_root->impl = 0;
 
+    // Initialize the /dev/ directory
+    initrd_dev = (fs_node_t*)kmalloc(sizeof(fs_node_t));
+    strcpy(initrd_root->name, "dev");
+    initrd_root->mask = initrd_root->uid = initrd_root->gid = initrd_root->inode = initrd_root->length = 0;
+    initrd_root->flags = FS_DIRECTORY;
+    initrd_root->read = 0;
+    initrd_root->write = 0;
+    initrd_root->open = 0;
+    initrd_root->close = 0;
+    initrd_root->readdir = &initrd_readdir;
+    initrd_root->finddir = &initrd_finddir;
+    initrd_root->ptr = 0;
+    initrd_root->impl = 0;
+
+    // Add dev and root directories to the ramdisk
+    // Let us first allocate space for them
+    root_nodes = (fs_node_t*)kmalloc(sizeof(fs_node_t) *initrd_header->nfiles);
+    nroot_nodes = initrd_header->nfiles;
+    // and then, add each file to an inode
+    for(uint32_t i = 0; i < initrd_header->nfiles; i++) {
+        file_headers[i].offset += multiboot_location;
+        // Create an inode for the file
+        strcpy(root_nodes[i].name, &file_headers[i].name);
+        root_nodes[i].mask = root_nodes[i].uid = root_nodes[i].gid = 0;
+        root_nodes[i].length = file_headers[i].length;
+        root_nodes[i].inode = i;
+        root_nodes[i].flags = FS_FILE;
+        root_nodes[i].read = &initrd_read;
+        root_nodes[i].write = 0;
+        root_nodes[i].readdir = 0;
+        root_nodes[i].finddir = 0;
+        root_nodes[i].open = 0;
+        root_nodes[i].close = 0;
+        root_nodes[i].impl = 0;
+    }
+
+    return initrd_root;
 }
 
 static uint32_t initrd_read(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
-    initrd_file_header_t header = file_header[node->inode];
+    initrd_file_header_t header = file_headers[node->inode];
     if(offset > header.length)
         return 0;
     if(offset+size > header.length)

kernel/drivers/initrd.h

@@ -13,6 +13,7 @@
 
 #include <stdint.h>
 #include "../libc/string.h"
+#include "../mem/kheap.h"
 #include "fs.h"
 
 typedef struct {
@@ -29,8 +30,5 @@ typedef struct {
 // Function to initialize initrd, we'll pass the multiboot
 // module as parameter
 fs_node_t *init_ramdisk(uint32_t multiboot_location);
-static uint32_t initrd_read(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
-static struct dirent *initrd_readdir(fs_node_t *node, uint32_t index);
-static fs_node_t *initrd_finddir(fs_node_t *node, uint8_t *name);
 
 #endif

kernel/kernel_main.c

@@ -10,6 +10,7 @@
 #include "drivers/idt.h"
 #include "drivers/timer.h"
 #include "drivers/keyboard.h"
+#include "drivers/initrd.h"
 #include "mem/paging.h"
 #include "mem/kheap.h"
 #include "mem/multiboot.h"
@@ -23,8 +24,22 @@
 #define PRTAT printf("\n["); printf_color(" ** ", LIGHT_BROWN, BLACK); printf("]"); // Ugly hack to print "[ * ]"
 #define PRTER printf("\n["); printf_color(" ERR ", LIGHT_RED, BLACK); printf("]"); // Ugly hack to print "[ ER ]"
 
+uint32_t initrd_setup( struct multiboot *mboot_ptr) {
+    if(mboot_ptr->mods_count < 0) { // Assert that initrd image is available
+        PRTER
+        puts("   - initrd not found!");
+        PANIC("Cannot find initrd");
+    }
 
-void kernel_main(unsigned long magic, uint32_t addr) {
+    extern uint32_t placement_addr;
+    uint32_t initrd_location = *((uint32_t*)mboot_ptr->mods_addr);
+    uint32_t initrd_end = *(uint32_t*)(mboot_ptr->mods_addr+4);
+    placement_addr = initrd_end;
+
+    return initrd_location;
+}
+
+void kernel_main(unsigned long magic, uint32_t addr, struct multiboot *mboot_ptr) {
     // First of all, check if we're booted by a Multiboot-compliant boot loader
     if(magic != MULTIBOOT2_BOOTLOADER_MAGIC) {
         PRTER
@@ -57,9 +72,16 @@ void kernel_main(unsigned long magic, uint32_t addr) {
     PRTOK
     printf("   - Loaded PS/2 driver");
 
+    uint32_t loc = initrd_setup(mboot_ptr); // Setup initial ramdisk
+
     init_paging(); // Initialize paging
     PRTOK
     printf("   - Loaded Paging");
+
+    // Now we can start initrd
+    fs_root = init_ramdisk(loc);
+    PRTOK
+    printf("    - Loaded Initrd");
     
     PRTAT
     printf("   - Testing heap...\t");

kernel/mem/multiboot.h

@@ -94,6 +94,36 @@ typedef unsigned short          multiboot_uint16_t;
 typedef unsigned int            multiboot_uint32_t;
 typedef unsigned long long      multiboot_uint64_t;
 
+struct multiboot
+{
+   multiboot_uint32_t flags;
+   multiboot_uint32_t mem_lower;
+   multiboot_uint32_t mem_upper;
+   multiboot_uint32_t boot_device;
+   multiboot_uint32_t cmdline;
+   int32_t mods_count;
+   multiboot_uint32_t mods_addr;
+   multiboot_uint32_t num;
+   multiboot_uint32_t size;
+   multiboot_uint32_t addr;
+   multiboot_uint32_t shndx;
+   multiboot_uint32_t mmap_length;
+   multiboot_uint32_t mmap_addr;
+   multiboot_uint32_t drives_length;
+   multiboot_uint32_t drives_addr;
+   multiboot_uint32_t config_table;
+   multiboot_uint32_t boot_loader_name;
+   multiboot_uint32_t apm_table;
+   multiboot_uint32_t vbe_control_info;
+   multiboot_uint32_t vbe_mode_info;
+   multiboot_uint32_t vbe_mode;
+   multiboot_uint32_t vbe_interface_seg;
+   multiboot_uint32_t vbe_interface_off;
+   multiboot_uint32_t vbe_interface_len;
+}  __attribute__((packed));
+
+typedef struct multiboot_header multiboot_header_t;
+
 struct multiboot_header
 {
   /*  Must be MULTIBOOT_MAGIC - see above. */