109 lines
4.2 KiB
C
109 lines
4.2 KiB
C
#include "initrd.h"
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// Private API to IO operations on dir and files
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static uint32_t initrd_read(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
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static struct dirent *initrd_readdir(fs_node_t *node, uint32_t index);
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static fs_node_t *initrd_finddir(fs_node_t *node, uint8_t *name);
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// Declare various things
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initrd_header_t *initrd_header; // Header
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initrd_file_header_t *file_headers; // List of headers
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fs_node_t *initrd_root; // Directory root node
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fs_node_t *initrd_dev; // Directory dev node(/dev)
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fs_node_t *root_nodes; // List of file nodes
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uint32_t nroot_nodes; // Number of file nodes
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struct dirent dirent;
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fs_node_t *init_ramdisk(uint32_t multiboot_location) {
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// Initialize main and file headers
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initrd_header = (initrd_header_t*)multiboot_location;
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file_headers = (initrd_file_header_t*)(multiboot_location+sizeof(initrd_header_t));
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// Initialize root directory
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initrd_root = (fs_node_t*)kmalloc(sizeof(fs_node_t));
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strcpy(initrd_root->name, (uint8_t*)"initrd");
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initrd_root->mask = initrd_root->uid = initrd_root->gid = initrd_root->inode = initrd_root->length = 0;
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initrd_root->flags = FS_DIRECTORY;
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initrd_root->read = 0;
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initrd_root->write = 0;
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initrd_root->open = 0;
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initrd_root->close = 0;
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initrd_root->readdir = &initrd_readdir;
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initrd_root->finddir = (finddir_type_t)&initrd_finddir;
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initrd_root->ptr = 0;
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initrd_root->impl = 0;
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// Initialize the /dev/ directory
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initrd_dev = (fs_node_t*)kmalloc(sizeof(fs_node_t));
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strcpy(initrd_root->name, (uint8_t*)"dev");
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initrd_root->mask = initrd_root->uid = initrd_root->gid = initrd_root->inode = initrd_root->length = 0;
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initrd_root->flags = FS_DIRECTORY;
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initrd_root->read = 0;
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initrd_root->write = 0;
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initrd_root->open = 0;
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initrd_root->close = 0;
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initrd_root->readdir = &initrd_readdir;
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initrd_root->finddir = (finddir_type_t)&initrd_finddir;
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initrd_root->ptr = 0;
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initrd_root->impl = 0;
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// Add dev and root directories to the ramdisk
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// Let us first allocate space for them
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root_nodes = (fs_node_t*)kmalloc(sizeof(fs_node_t) *initrd_header->nfiles);
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nroot_nodes = initrd_header->nfiles;
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// and then, add each file to an inode
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for(uint32_t i = 0; i < initrd_header->nfiles; i++) {
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file_headers[i].offset += multiboot_location;
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// Create an inode for the file
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strcpy(root_nodes[i].name, (uint8_t*)&file_headers[i].name);
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root_nodes[i].mask = root_nodes[i].uid = root_nodes[i].gid = 0;
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root_nodes[i].length = file_headers[i].length;
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root_nodes[i].inode = i;
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root_nodes[i].flags = FS_FILE;
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root_nodes[i].read = &initrd_read;
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root_nodes[i].write = 0;
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root_nodes[i].readdir = 0;
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root_nodes[i].finddir = 0;
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root_nodes[i].open = 0;
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root_nodes[i].close = 0;
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root_nodes[i].impl = 0;
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}
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return initrd_root;
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}
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static uint32_t initrd_read(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
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initrd_file_header_t header = file_headers[node->inode];
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if(offset > header.length)
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return 0;
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if(offset+size > header.length)
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size = header.length-offset;
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memcpy(buffer, (uint8_t*) (header.offset+offset), size);
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return size;
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}
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static struct dirent *initrd_readdir(fs_node_t *node, uint32_t index) {
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if(node == initrd_root && index == 0) {
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strcpy(dirent.name, (uint8_t*)"dev");
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dirent.name[3] = 0; // Add null terminator to the string
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dirent.ino = 0;
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return &dirent;
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}
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if(index-1 >= (uint32_t)&root_nodes)
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return 0;
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strcpy(dirent.name, root_nodes[index-1].name);
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dirent.name[strlen(root_nodes[index-1].name)] = 0; // Add null terminator
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dirent.ino = root_nodes[index-1].inode;
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return &dirent;
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}
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static fs_node_t *initrd_finddir(fs_node_t *node, uint8_t *name) {
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if(node == initrd_root && !strcmp(name, (uint8_t*)"dev"))
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return initrd_dev;
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for(uint32_t i = 0; i < nroot_nodes; i++)
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if(!strcmp(name, root_nodes[i].name))
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return &root_nodes[i];
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return 0;
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} |