111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
/* vim: tabstop=4 shiftwidth=4 noexpandtab
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* This file is part of ToaruOS and is released under the terms
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* of the NCSA / University of Illinois License - see LICENSE.md
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* Copyright (C) 2014-2018 K. Lange
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*
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* Ramdisk driver.
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*
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* Provide raw block access to files loaded into kernel memory.
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*/
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#include <kernel/system.h>
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#include <kernel/logging.h>
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#include <kernel/module.h>
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#include <kernel/fs.h>
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#include <kernel/printf.h>
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#include <kernel/mem.h>
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static uint32_t read_ramdisk(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
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static uint32_t write_ramdisk(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
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static void open_ramdisk(fs_node_t *node, unsigned int flags);
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static void close_ramdisk(fs_node_t *node);
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static uint32_t read_ramdisk(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
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if (offset > node->length) {
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return 0;
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}
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if (offset + size > node->length) {
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unsigned int i = node->length - offset;
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size = i;
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}
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memcpy(buffer, (void *)(node->inode + offset), size);
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return size;
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}
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static uint32_t write_ramdisk(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
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if (offset > node->length) {
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return 0;
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}
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if (offset + size > node->length) {
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unsigned int i = node->length - offset;
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size = i;
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}
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memcpy((void *)(node->inode + offset), buffer, size);
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return size;
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}
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static void open_ramdisk(fs_node_t * node, unsigned int flags) {
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return;
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}
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static void close_ramdisk(fs_node_t * node) {
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return;
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}
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static int ioctl_ramdisk(fs_node_t * node, int request, void * argp) {
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switch (request) {
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case 0x4001:
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if (current_process->user != 0) {
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return -EPERM;
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} else {
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/* Clear all of the memory used by this ramdisk */
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for (uintptr_t i = node->inode; i < node->inode + node->length; i += 0x1000) {
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clear_frame(i);
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}
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/* Mark the file length as 0 */
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node->length = 0;
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return 0;
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}
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default:
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return -EINVAL;
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}
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}
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static fs_node_t * ramdisk_device_create(int device_number, uintptr_t location, size_t size) {
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fs_node_t * fnode = malloc(sizeof(fs_node_t));
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memset(fnode, 0x00, sizeof(fs_node_t));
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fnode->inode = location;
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sprintf(fnode->name, "ram%d", device_number);
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fnode->uid = 0;
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fnode->gid = 0;
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fnode->mask = 0660;
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fnode->length = size;
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fnode->flags = FS_BLOCKDEVICE;
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fnode->read = read_ramdisk;
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fnode->write = write_ramdisk;
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fnode->open = open_ramdisk;
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fnode->close = close_ramdisk;
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fnode->ioctl = ioctl_ramdisk;
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return fnode;
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}
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static int last_device_number = 0;
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fs_node_t * ramdisk_mount(uintptr_t location, size_t size) {
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fs_node_t * ramdisk = ramdisk_device_create(last_device_number, location, size);
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if (ramdisk) {
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char tmp[64];
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sprintf(tmp, "/dev/%s", ramdisk->name);
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vfs_mount(tmp, ramdisk);
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last_device_number += 1;
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return ramdisk;
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}
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return NULL;
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}
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