hos/kernel/fs/vfs.c

// vfs.c
// Author: Josh Holtrop
// Date: 08/22/04
// Modified: 12/21/04

#include "hos_defines.h"
#include "kout.h"
#include "fs/vfs.h"
#include "fs/ext2.h"
#include "kernel.h"
#include "mm/vmm.h"
#include "lang/lang.h"

vfs_fs_t *fses[VFS_MAX_FS];			// a vfs_fs structure for every filesystem we support
vfs_mount_node_t *mounts;

// basic initialization routine, init all filesystem drivers
int	vfs_init()
{
	k_check(ext2_init(FS_EXT2), "ext2_init() failed!");
	return 0;
}

// called by a filesystem driver to let us know that it is ready to handle fs requests
int	vfs_register_fs(int fsn, vfs_fs_t *fs)
{
	if (fsn < 0 || fsn >= VFS_MAX_FS || fses[fsn])
	{
		kprintf("Invalid filesystem register: %d\n", fsn);
		return -1;
	}
	fses[fsn] = fs;
	return 0;
}

// called to mount a block device with a certain filesystem to a part of our VFS Mount Tree
int	vfs_mount(major_t maj, minor_t min, int fsType, char *mountPoint)
{
	if (fsType < 0 || fsType >= VFS_MAX_FS || !fses[fsType])
		return -1;				// invalid filesystem type
	if (!strcmp("/", mountPoint))
	{
		if (mounts)
			return -2;			// root already mounted
		void *super = fses[fsType]->mount_super(maj, min);
		vfs_mount_t *mnt = New(vfs_mount_t);
		mnt->refs = 0;
		mnt->fs = fsType;
		mnt->major = maj;
		mnt->minor = min;
		mnt->super = super;
		vfs_mount_node_t *node = New(vfs_mount_node_t);
		mount = node;
		node->next = NULL;
		node->mount = mnt;
		node->vfs_inode = 0;
		return 0;
	}
	if (mountPoint[0] != '/')
		return -3;				// mount point must be absolute
	int l = strlen(mountPoint);
	if (l < 2)
		return -4;				// mount point must be non-null string
	return -5;
}

vfs_inode_t	vfs_get_inode_number(char *path)
{
	if (path[0] != '/')
		return 0;
	vfs_file_addr_t file_addr;
	file_addr.mount = mounts->mount;
	file_addr.inode = fses[file_addr.mount->fsType]->get_root_inode(file_addr.mount);

}


// stat a file, fills a vfs_stat_t structure with stat information and returns standard status
int	vfs_stat(char *file, vfs_stat_t *stat)
{
	vfs_mount_match_t match = vfs_get_rel_path(file);
	if (match.mount == NULL)
		return -256;
	if (fses[match.mount->fs]->stat)
		return fses[match.mount->fs]->stat(match.mount, file + match.length - 1, stat);
	return -257;
}


vfs_open_file_t *vfs_open_dir(vfs_inode_t inode)
{
	vfs_open_file_t *open_dir = New(vfs_open_file_t);
	if (fses[match.mount->fs]->open_dir && !(fses[match.mount->fs]->open_dir(match.mount, file + match.length - 1, open_dir)))
	{
		open_dir->mount = match.mount;
		return open_dir;
	}
	kfree(open_dir);
	return NULL;
}

int	vfs_read_dir(vfs_open_file_t *open_dir, vfs_dir_entry_t *dentry)
{
	return !(fses[open_dir->mount->fs]->read_dir &&
		!(fses[open_dir->mount->fs]->read_dir(open_dir->mount, open_dir, dentry)));
}

int	vfs_close_dir(vfs_open_file_t *open_dir)
{
	int status = 0;
	if (fses[open_dir->mount->fs]->close_dir)
		status = fses[open_dir->mount->fs]->close_dir(open_dir->mount, open_dir);
	kfree(open_dir);
	return status;
}


vfs_open_file_t *vfs_open_block_file(char *file)
{
	vfs_mount_match_t match = vfs_get_rel_path(file);
	if (match.mount == NULL)
		return NULL;
	vfs_open_file_t *open_file = New(vfs_open_file_t);
	if (fses[match.mount->fs]->open_block_file && !(fses[match.mount->fs]->open_block_file(match.mount, file + match.length - 1, open_file)))
	{
		open_file->mount = match.mount;
		return open_file;
	}
	kfree(open_file);
	return NULL;
}

int	vfs_read_block_file(vfs_open_file_t *open_file, void *buffer)
{
	if (fses[open_file->mount->fs]->read_block_file)
		return fses[open_file->mount->fs]->read_block_file(open_file->mount, open_file, buffer);
	return 0;
}

int	vfs_block_file_seek(vfs_open_file_t *open_file, u32_t block_number)
{
	if (fses[open_file->mount->fs]->block_file_seek)
		return fses[open_file->mount->fs]->block_file_seek(open_file->mount, open_file, block_number);
	return -1;
}

int	vfs_close_block_file(vfs_open_file_t *open_file)
{
	int status = 0;
	if (fses[open_file->mount->fs]->close_block_file)
		status = fses[open_file->mount->fs]->close_block_file(open_file->mount, open_file);
	kfree(open_file);
	return status;
}


// DEBUG routines to draw the VFS Mount Tree
/******************************************/
void	vfs_dump_tree()
{
	if (!vfsMountTree)
		kprintf("vfsMountTree == NULL!\n");
	else
		vfs_dump_node(vfsMountTree, 0);
}

void	vfs_dump_node(vfs_node_t *node, int level)
{
	int i;
	for (i = 0; i < level; i++)
	{
		putc(' ');
	}
	kprintf("%c (0x%x) mount: 0x%x, up: 0x%x, next:0x%x, down:0x%x\n", node->chr, node, node->mount, node->up, node->next, node->down);
	node = node->down;
	if (!node)
		return;
	while (node)
	{
		vfs_dump_node(node, level + 1);
		node = node->next;
	}
}
/******************************************/