1045 lines
25 KiB
C
1045 lines
25 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) 2011-2014 Kevin Lange
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* Copyright (C) 2014 Lioncash
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* Copyright (C) 2012 Tianyi Wang
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*
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* Virtual File System
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*
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*/
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#include <kernel/system.h>
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#include <kernel/fs.h>
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#include <kernel/printf.h>
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#include <kernel/list.h>
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#include <kernel/process.h>
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#include <kernel/logging.h>
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#include <kernel/hashmap.h>
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#define MAX_SYMLINK_DEPTH 8
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#define MAX_SYMLINK_SIZE 4096
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tree_t * fs_tree = NULL; /* File system mountpoint tree */
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fs_node_t * fs_root = NULL; /* Pointer to the root mount fs_node (must be some form of filesystem, even ramdisk) */
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hashmap_t * fs_types = NULL;
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int has_permission(fs_node_t * node, int permission_bit) {
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if (!node) return 0;
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if (current_process->user == 0) {
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return 1;
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}
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uint32_t permissions = node->mask;
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uint8_t user_perm = (permissions >> 6) & 07;
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//uint8_t group_perm = (permissions >> 3) & 07;
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uint8_t other_perm = (permissions) & 07;
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if (current_process->user == node->uid) {
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return (permission_bit & user_perm);
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/* TODO group permissions? */
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} else {
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return (permission_bit & other_perm);
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}
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}
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static struct dirent * readdir_mapper(fs_node_t *node, uint32_t index) {
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tree_node_t * d = (tree_node_t *)node->device;
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if (!d) return NULL;
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if (index == 0) {
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struct dirent * dir = malloc(sizeof(struct dirent));
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strcpy(dir->name, ".");
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dir->ino = 0;
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return dir;
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} else if (index == 1) {
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struct dirent * dir = malloc(sizeof(struct dirent));
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strcpy(dir->name, "..");
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dir->ino = 1;
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return dir;
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}
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index -= 2;
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unsigned int i = 0;
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foreach(child, d->children) {
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if (i == index) {
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/* Recursively print the children */
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tree_node_t * tchild = (tree_node_t *)child->value;
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struct vfs_entry * n = (struct vfs_entry *)tchild->value;
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struct dirent * dir = malloc(sizeof(struct dirent));
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size_t len = strlen(n->name) + 1;
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memcpy(&dir->name, n->name, MIN(256, len));
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dir->ino = i;
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return dir;
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}
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++i;
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}
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return NULL;
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}
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static fs_node_t * vfs_mapper(void) {
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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->mask = 0666;
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fnode->flags = FS_DIRECTORY;
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fnode->readdir = readdir_mapper;
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return fnode;
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}
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/**
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* selectcheck_fs: Check if a read from this file would block.
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*/
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int selectcheck_fs(fs_node_t * node) {
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if (!node) return -1;
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if (node->selectcheck) {
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return node->selectcheck(node);
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}
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return -1;
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}
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/**
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* selectwait_fs: Inform a node that it should alert the current_process.
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*/
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int selectwait_fs(fs_node_t * node, void * process) {
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if (!node) return -1;
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if (node->selectwait) {
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return node->selectwait(node, process);
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}
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return -1;
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}
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/**
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* read_fs: Read a file system node based on its underlying type.
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*
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* @param node Node to read
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* @param offset Offset into the node data to read from
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* @param size How much data to read (in bytes)
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* @param buffer A buffer to copy of the read data into
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* @returns Bytes read
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*/
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uint32_t read_fs(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
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if (!node) return -1;
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if (node->read) {
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uint32_t ret = node->read(node, offset, size, buffer);
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return ret;
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} else {
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return -1;
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}
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}
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/**
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* write_fs: Write a file system node based on its underlying type.
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*
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* @param node Node to write to
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* @param offset Offset into the node data to write to
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* @param size How much data to write (in bytes)
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* @param buffer A buffer to copy from
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* @returns Bytes written
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*/
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uint32_t write_fs(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer) {
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if (!node) return -1;
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if (node->write) {
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uint32_t ret = node->write(node, offset, size, buffer);
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return ret;
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} else {
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return -1;
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}
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}
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//volatile uint8_t tmp_refcount_lock = 0;
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static spin_lock_t tmp_refcount_lock = { 0 };
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void vfs_lock(fs_node_t * node) {
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spin_lock(tmp_refcount_lock);
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node->refcount = -1;
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spin_unlock(tmp_refcount_lock);
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}
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/**
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* open_fs: Open a file system node.
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*
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* @param node Node to open
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* @param flags Same as open, specifies read/write/append/truncate
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*/
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void open_fs(fs_node_t *node, unsigned int flags) {
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if (!node) return;
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if (node->refcount >= 0) {
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spin_lock(tmp_refcount_lock);
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node->refcount++;
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spin_unlock(tmp_refcount_lock);
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}
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if (node->open) {
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node->open(node, flags);
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}
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}
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/**
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* close_fs: Close a file system node
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*
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* @param node Node to close
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*/
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void close_fs(fs_node_t *node) {
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assert(node != fs_root && "Attempted to close the filesystem root. kablooey");
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if (!node) {
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debug_print(WARNING, "Double close? This isn't an fs_node.");
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return;
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}
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if (node->refcount == -1) return;
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spin_lock(tmp_refcount_lock);
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node->refcount--;
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if (node->refcount == 0) {
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debug_print(NOTICE, "Node refcount [%s] is now 0: %d", node->name, node->refcount);
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if (node->close) {
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node->close(node);
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}
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free(node);
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}
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spin_unlock(tmp_refcount_lock);
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}
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/**
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* chmod_fs
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*/
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int chmod_fs(fs_node_t *node, int mode) {
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if (node->chmod) {
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return node->chmod(node, mode);
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}
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return 0;
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}
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/**
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* chown_fs
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*/
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int chown_fs(fs_node_t *node, int uid, int gid) {
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if (node->chown) {
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return node->chown(node, uid, gid);
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}
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return 0;
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}
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/**
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* readdir_fs: Read a directory for the requested index
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*
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* @param node Directory to read
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* @param index Offset to look for
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* @returns A dirent object.
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*/
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struct dirent *readdir_fs(fs_node_t *node, uint32_t index) {
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if (!node) return NULL;
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if ((node->flags & FS_DIRECTORY) && node->readdir) {
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struct dirent *ret = node->readdir(node, index);
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return ret;
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} else {
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return (struct dirent *)NULL;
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}
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}
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/**
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* finddir_fs: Find the requested file in the directory and return an fs_node for it
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*
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* @param node Directory to search
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* @param name File to look for
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* @returns An fs_node that the caller can free
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*/
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fs_node_t *finddir_fs(fs_node_t *node, char *name) {
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if (!node) return NULL;
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if ((node->flags & FS_DIRECTORY) && node->finddir) {
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fs_node_t *ret = node->finddir(node, name);
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return ret;
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} else {
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debug_print(WARNING, "Node passed to finddir_fs isn't a directory!");
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debug_print(WARNING, "node = 0x%x, name = %s", node, name);
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return (fs_node_t *)NULL;
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}
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}
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/**
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* ioctl_fs: Control Device
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*
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* @param node Device node to control
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* @param request Device-specific request code
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* @param argp Depends on `request`
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* @returns Depends on `request`
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*/
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int ioctl_fs(fs_node_t *node, int request, void * argp) {
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if (!node) return -1;
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if (node->ioctl) {
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return node->ioctl(node, request, argp);
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} else {
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return -1; /* TODO Should actually be ENOTTY, but we're bad at error numbers */
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}
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}
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/*
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* XXX: The following two function should be replaced with
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* one function to create children of directory nodes.
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* There is no fundamental difference between a directory
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* and a file, thus, the use of flag sets should suffice
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*/
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int create_file_fs(char *name, uint16_t permission) {
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fs_node_t * parent;
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char *cwd = (char *)(current_process->wd_name);
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char *path = canonicalize_path(cwd, name);
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char * parent_path = malloc(strlen(path) + 4);
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sprintf(parent_path, "%s/..", path);
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char * f_path = path + strlen(path) - 1;
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while (f_path > path) {
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if (*f_path == '/') {
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f_path += 1;
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break;
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}
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f_path--;
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}
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while (*f_path == '/') {
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f_path++;
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}
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debug_print(WARNING, "creating file %s within %s (hope these strings are good)", f_path, parent_path);
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parent = kopen(parent_path, 0);
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free(parent_path);
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if (!parent) {
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debug_print(WARNING, "failed to open parent");
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free(path);
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return -1;
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}
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if (!has_permission(parent, 02)) {
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debug_print(WARNING, "bad permissions");
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return -EACCES;
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}
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if (parent->create) {
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parent->create(parent, f_path, permission);
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}
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free(path);
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free(parent);
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return 0;
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}
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int unlink_fs(char * name) {
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fs_node_t * parent;
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char *cwd = (char *)(current_process->wd_name);
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char *path = canonicalize_path(cwd, name);
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char * parent_path = malloc(strlen(path) + 4);
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sprintf(parent_path, "%s/..", path);
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char * f_path = path + strlen(path) - 1;
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while (f_path > path) {
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if (*f_path == '/') {
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f_path += 1;
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break;
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}
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f_path--;
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}
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while (*f_path == '/') {
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f_path++;
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}
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debug_print(WARNING, "unlinking file %s within %s (hope these strings are good)", f_path, parent_path);
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parent = kopen(parent_path, 0);
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free(parent_path);
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if (!parent) {
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free(path);
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return -1;
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}
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if (parent->unlink) {
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parent->unlink(parent, f_path);
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}
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free(path);
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free(parent);
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return 0;
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}
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int mkdir_fs(char *name, uint16_t permission) {
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fs_node_t * parent;
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char *cwd = (char *)(current_process->wd_name);
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char *path = canonicalize_path(cwd, name);
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char * parent_path = malloc(strlen(path) + 4);
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sprintf(parent_path, "%s/..", path);
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fs_node_t * this = kopen(path, 0);
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int _exists = 0;
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if (this) {
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debug_print(WARNING, "Tried to mkdir a dir that already exists? (%s)", path);
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_exists = 1;
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}
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char * f_path = path + strlen(path) - 1;
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while (f_path > path) {
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if (*f_path == '/') {
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f_path += 1;
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break;
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}
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f_path--;
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}
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while (*f_path == '/') {
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f_path++;
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}
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debug_print(WARNING, "creating directory %s within %s (hope these strings are good)", f_path, parent_path);
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parent = kopen(parent_path, 0);
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free(parent_path);
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if (!parent) {
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free(path);
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if (_exists) {
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return -EEXIST;
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}
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return -1;
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}
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if (parent->mkdir) {
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parent->mkdir(parent, f_path, permission);
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}
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free(path);
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close_fs(parent);
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if (_exists) {
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return -EEXIST;
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}
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return 0;
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}
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fs_node_t *clone_fs(fs_node_t *source) {
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if (!source) return NULL;
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if (source->refcount >= 0) {
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spin_lock(tmp_refcount_lock);
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source->refcount++;
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spin_unlock(tmp_refcount_lock);
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}
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return source;
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}
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int symlink_fs(char * target, char * name) {
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fs_node_t * parent;
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char *cwd = (char *)(current_process->wd_name);
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char *path = canonicalize_path(cwd, name);
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char * parent_path = malloc(strlen(path) + 4);
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sprintf(parent_path, "%s/..", path);
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char * f_path = path + strlen(path) - 1;
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while (f_path > path) {
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if (*f_path == '/') {
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f_path += 1;
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break;
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}
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f_path--;
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}
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debug_print(NOTICE, "creating symlink %s within %s", f_path, parent_path);
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parent = kopen(parent_path, 0);
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free(parent_path);
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if (!parent) {
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free(path);
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return -1;
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}
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if (parent->symlink) {
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parent->symlink(parent, target, f_path);
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}
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free(path);
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close_fs(parent);
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return 0;
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}
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int readlink_fs(fs_node_t *node, char * buf, uint32_t size) {
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if (!node) return -1;
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if (node->readlink) {
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return node->readlink(node, buf, size);
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} else {
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return -1;
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}
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}
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/**
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* canonicalize_path: Canonicalize a path.
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*
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* @param cwd Current working directory
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* @param input Path to append or canonicalize on
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* @returns An absolute path string
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*/
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char *canonicalize_path(char *cwd, char *input) {
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/* This is a stack-based canonicalizer; we use a list as a stack */
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list_t *out = list_create();
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/*
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* If we have a relative path, we need to canonicalize
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* the working directory and insert it into the stack.
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*/
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if (strlen(input) && input[0] != PATH_SEPARATOR) {
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/* Make a copy of the working directory */
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char *path = malloc((strlen(cwd) + 1) * sizeof(char));
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memcpy(path, cwd, strlen(cwd) + 1);
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/* Setup tokenizer */
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char *pch;
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char *save;
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pch = strtok_r(path,PATH_SEPARATOR_STRING,&save);
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/* Start tokenizing */
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while (pch != NULL) {
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/* Make copies of the path elements */
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char *s = malloc(sizeof(char) * (strlen(pch) + 1));
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memcpy(s, pch, strlen(pch) + 1);
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/* And push them */
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list_insert(out, s);
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pch = strtok_r(NULL,PATH_SEPARATOR_STRING,&save);
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}
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free(path);
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}
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/* Similarly, we need to push the elements from the new path */
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char *path = malloc((strlen(input) + 1) * sizeof(char));
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memcpy(path, input, strlen(input) + 1);
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/* Initialize the tokenizer... */
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char *pch;
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char *save;
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pch = strtok_r(path,PATH_SEPARATOR_STRING,&save);
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/*
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* Tokenize the path, this time, taking care to properly
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* handle .. and . to represent up (stack pop) and current
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* (do nothing)
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*/
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while (pch != NULL) {
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if (!strcmp(pch,PATH_UP)) {
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/*
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* Path = ..
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* Pop the stack to move up a directory
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*/
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node_t * n = list_pop(out);
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if (n) {
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free(n->value);
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free(n);
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}
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} else if (!strcmp(pch,PATH_DOT)) {
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/*
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* Path = .
|
|
* Do nothing
|
|
*/
|
|
} else {
|
|
/*
|
|
* Regular path, push it
|
|
* XXX: Path elements should be checked for existence!
|
|
*/
|
|
char * s = malloc(sizeof(char) * (strlen(pch) + 1));
|
|
memcpy(s, pch, strlen(pch) + 1);
|
|
list_insert(out, s);
|
|
}
|
|
pch = strtok_r(NULL, PATH_SEPARATOR_STRING, &save);
|
|
}
|
|
free(path);
|
|
|
|
/* Calculate the size of the path string */
|
|
size_t size = 0;
|
|
foreach(item, out) {
|
|
/* Helpful use of our foreach macro. */
|
|
size += strlen(item->value) + 1;
|
|
}
|
|
|
|
/* join() the list */
|
|
char *output = malloc(sizeof(char) * (size + 1));
|
|
char *output_offset = output;
|
|
if (size == 0) {
|
|
/*
|
|
* If the path is empty, we take this to mean the root
|
|
* thus we synthesize a path of "/" to return.
|
|
*/
|
|
output = realloc(output, sizeof(char) * 2);
|
|
output[0] = PATH_SEPARATOR;
|
|
output[1] = '\0';
|
|
} else {
|
|
/* Otherwise, append each element together */
|
|
foreach(item, out) {
|
|
output_offset[0] = PATH_SEPARATOR;
|
|
output_offset++;
|
|
memcpy(output_offset, item->value, strlen(item->value) + 1);
|
|
output_offset += strlen(item->value);
|
|
}
|
|
}
|
|
|
|
/* Clean up the various things we used to get here */
|
|
list_destroy(out);
|
|
list_free(out);
|
|
free(out);
|
|
|
|
/* And return a working, absolute path */
|
|
return output;
|
|
}
|
|
|
|
void vfs_install(void) {
|
|
/* Initialize the mountpoint tree */
|
|
fs_tree = tree_create();
|
|
|
|
struct vfs_entry * root = malloc(sizeof(struct vfs_entry));
|
|
|
|
root->name = strdup("[root]");
|
|
root->file = NULL; /* Nothing mounted as root */
|
|
root->fs_type = NULL;
|
|
root->device = NULL;
|
|
|
|
tree_set_root(fs_tree, root);
|
|
|
|
fs_types = hashmap_create(5);
|
|
}
|
|
|
|
int vfs_register(char * name, vfs_mount_callback callback) {
|
|
if (hashmap_get(fs_types, name)) return 1;
|
|
hashmap_set(fs_types, name, (void *)(uintptr_t)callback);
|
|
return 0;
|
|
}
|
|
|
|
int vfs_mount_type(char * type, char * arg, char * mountpoint) {
|
|
|
|
vfs_mount_callback t = (vfs_mount_callback)(uintptr_t)hashmap_get(fs_types, type);
|
|
if (!t) {
|
|
debug_print(WARNING, "Unknown filesystem type: %s", type);
|
|
return -ENODEV;
|
|
}
|
|
|
|
fs_node_t * n = t(arg, mountpoint);
|
|
|
|
if (!n) return -EINVAL;
|
|
|
|
tree_node_t * node = vfs_mount(mountpoint, n);
|
|
if (node && node->value) {
|
|
struct vfs_entry * ent = (struct vfs_entry *)node->value;
|
|
ent->fs_type = strdup(type);
|
|
ent->device = strdup(arg);
|
|
}
|
|
|
|
debug_print(NOTICE, "Mounted %s[%s] to %s: 0x%x", type, arg, mountpoint, n);
|
|
debug_print_vfs_tree();
|
|
|
|
return 0;
|
|
}
|
|
|
|
//volatile uint8_t tmp_vfs_lock = 0;
|
|
static spin_lock_t tmp_vfs_lock = { 0 };
|
|
/**
|
|
* vfs_mount - Mount a file system to the specified path.
|
|
*
|
|
* For example, if we have an EXT2 filesystem with a root node
|
|
* of ext2_root and we want to mount it to /, we would run
|
|
* vfs_mount("/", ext2_root); - or, if we have a procfs node,
|
|
* we could mount that to /dev/procfs. Individual files can also
|
|
* be mounted.
|
|
*
|
|
* Paths here must be absolute.
|
|
*/
|
|
void * vfs_mount(char * path, fs_node_t * local_root) {
|
|
if (!fs_tree) {
|
|
debug_print(ERROR, "VFS hasn't been initialized, you can't mount things yet!");
|
|
return NULL;
|
|
}
|
|
if (!path || path[0] != '/') {
|
|
debug_print(ERROR, "Path must be absolute for mountpoint.");
|
|
return NULL;
|
|
}
|
|
|
|
spin_lock(tmp_vfs_lock);
|
|
|
|
local_root->refcount = -1;
|
|
|
|
tree_node_t * ret_val = NULL;
|
|
|
|
char * p = strdup(path);
|
|
char * i = p;
|
|
|
|
int path_len = strlen(p);
|
|
|
|
/* Chop the path up */
|
|
while (i < p + path_len) {
|
|
if (*i == PATH_SEPARATOR) {
|
|
*i = '\0';
|
|
}
|
|
i++;
|
|
}
|
|
/* Clean up */
|
|
p[path_len] = '\0';
|
|
i = p + 1;
|
|
|
|
/* Root */
|
|
tree_node_t * root_node = fs_tree->root;
|
|
|
|
if (*i == '\0') {
|
|
/* Special case, we're trying to set the root node */
|
|
struct vfs_entry * root = (struct vfs_entry *)root_node->value;
|
|
if (root->file) {
|
|
debug_print(WARNING, "Path %s already mounted, unmount before trying to mount something else.", path);
|
|
}
|
|
root->file = local_root;
|
|
/* We also keep a legacy shortcut around for that */
|
|
fs_root = local_root;
|
|
ret_val = root_node;
|
|
} else {
|
|
tree_node_t * node = root_node;
|
|
char * at = i;
|
|
while (1) {
|
|
if (at >= p + path_len) {
|
|
break;
|
|
}
|
|
int found = 0;
|
|
debug_print(NOTICE, "Searching for %s", at);
|
|
foreach(child, node->children) {
|
|
tree_node_t * tchild = (tree_node_t *)child->value;
|
|
struct vfs_entry * ent = (struct vfs_entry *)tchild->value;
|
|
if (!strcmp(ent->name, at)) {
|
|
found = 1;
|
|
node = tchild;
|
|
ret_val = node;
|
|
break;
|
|
}
|
|
}
|
|
if (!found) {
|
|
debug_print(NOTICE, "Did not find %s, making it.", at);
|
|
struct vfs_entry * ent = malloc(sizeof(struct vfs_entry));
|
|
ent->name = strdup(at);
|
|
ent->file = NULL;
|
|
ent->device = NULL;
|
|
ent->fs_type = NULL;
|
|
node = tree_node_insert_child(fs_tree, node, ent);
|
|
}
|
|
at = at + strlen(at) + 1;
|
|
}
|
|
struct vfs_entry * ent = (struct vfs_entry *)node->value;
|
|
if (ent->file) {
|
|
debug_print(WARNING, "Path %s already mounted, unmount before trying to mount something else.", path);
|
|
}
|
|
ent->file = local_root;
|
|
ret_val = node;
|
|
}
|
|
|
|
free(p);
|
|
spin_unlock(tmp_vfs_lock);
|
|
return ret_val;
|
|
}
|
|
|
|
void map_vfs_directory(char * c) {
|
|
fs_node_t * f = vfs_mapper();
|
|
struct vfs_entry * e = vfs_mount(c, f);
|
|
if (!strcmp(c, "/")) {
|
|
f->device = fs_tree->root;
|
|
} else {
|
|
f->device = e;
|
|
}
|
|
}
|
|
|
|
|
|
void debug_print_vfs_tree_node(tree_node_t * node, size_t height) {
|
|
/* End recursion on a blank entry */
|
|
if (!node) return;
|
|
char * tmp = malloc(512);
|
|
memset(tmp, 0, 512);
|
|
char * c = tmp;
|
|
/* Indent output */
|
|
for (uint32_t i = 0; i < height; ++i) {
|
|
c += sprintf(c, " ");
|
|
}
|
|
/* Get the current process */
|
|
struct vfs_entry * fnode = (struct vfs_entry *)node->value;
|
|
/* Print the process name */
|
|
if (fnode->file) {
|
|
c += sprintf(c, "%s → %s 0x%x (%s, %s)", fnode->name, fnode->device, fnode->file, fnode->fs_type, fnode->file->name);
|
|
} else {
|
|
c += sprintf(c, "%s → (empty)", fnode->name);
|
|
}
|
|
/* Linefeed */
|
|
debug_print(NOTICE, "%s", tmp);
|
|
free(tmp);
|
|
foreach(child, node->children) {
|
|
/* Recursively print the children */
|
|
debug_print_vfs_tree_node(child->value, height + 1);
|
|
}
|
|
}
|
|
|
|
void debug_print_vfs_tree(void) {
|
|
debug_print_vfs_tree_node(fs_tree->root, 0);
|
|
}
|
|
|
|
/**
|
|
* get_mount_point
|
|
*
|
|
*/
|
|
fs_node_t *get_mount_point(char * path, unsigned int path_depth, char **outpath, unsigned int * outdepth) {
|
|
size_t depth;
|
|
|
|
for (depth = 0; depth <= path_depth; ++depth) {
|
|
path += strlen(path) + 1;
|
|
}
|
|
|
|
/* Last available node */
|
|
fs_node_t * last = fs_root;
|
|
tree_node_t * node = fs_tree->root;
|
|
|
|
char * at = *outpath;
|
|
int _depth = 1;
|
|
int _tree_depth = 0;
|
|
|
|
while (1) {
|
|
if (at >= path) {
|
|
break;
|
|
}
|
|
int found = 0;
|
|
debug_print(INFO, "Searching for %s", at);
|
|
foreach(child, node->children) {
|
|
tree_node_t * tchild = (tree_node_t *)child->value;
|
|
struct vfs_entry * ent = (struct vfs_entry *)tchild->value;
|
|
if (!strcmp(ent->name, at)) {
|
|
found = 1;
|
|
node = tchild;
|
|
at = at + strlen(at) + 1;
|
|
if (ent->file) {
|
|
_tree_depth = _depth;
|
|
last = ent->file;
|
|
*outpath = at;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
if (!found) {
|
|
break;
|
|
}
|
|
_depth++;
|
|
}
|
|
|
|
*outdepth = _tree_depth;
|
|
|
|
if (last) {
|
|
fs_node_t * last_clone = malloc(sizeof(fs_node_t));
|
|
memcpy(last_clone, last, sizeof(fs_node_t));
|
|
return last_clone;
|
|
}
|
|
return last;
|
|
}
|
|
|
|
|
|
|
|
fs_node_t *kopen_recur(char *filename, uint32_t flags, uint32_t symlink_depth, char *relative_to) {
|
|
/* Simple sanity checks that we actually have a file system */
|
|
if (!filename) {
|
|
return NULL;
|
|
}
|
|
|
|
/* Canonicalize the (potentially relative) path... */
|
|
char *path = canonicalize_path(relative_to, filename);
|
|
/* And store the length once to save recalculations */
|
|
size_t path_len = strlen(path);
|
|
|
|
/* If strlen(path) == 1, then path = "/"; return root */
|
|
if (path_len == 1) {
|
|
/* Clone the root file system node */
|
|
fs_node_t *root_clone = malloc(sizeof(fs_node_t));
|
|
memcpy(root_clone, fs_root, sizeof(fs_node_t));
|
|
|
|
/* Free the path */
|
|
free(path);
|
|
|
|
open_fs(root_clone, flags);
|
|
|
|
/* And return the clone */
|
|
return root_clone;
|
|
}
|
|
|
|
/* Otherwise, we need to break the path up and start searching */
|
|
char *path_offset = path;
|
|
uint32_t path_depth = 0;
|
|
while (path_offset < path + path_len) {
|
|
/* Find each PATH_SEPARATOR */
|
|
if (*path_offset == PATH_SEPARATOR) {
|
|
*path_offset = '\0';
|
|
path_depth++;
|
|
}
|
|
path_offset++;
|
|
}
|
|
/* Clean up */
|
|
path[path_len] = '\0';
|
|
path_offset = path + 1;
|
|
|
|
/*
|
|
* At this point, the path is tokenized and path_offset points
|
|
* to the first token (directory) and path_depth is the number
|
|
* of directories in the path
|
|
*/
|
|
|
|
/*
|
|
* Dig through the (real) tree to find the file
|
|
*/
|
|
unsigned int depth = 0;
|
|
/* Find the mountpoint for this file */
|
|
fs_node_t *node_ptr = get_mount_point(path, path_depth, &path_offset, &depth);
|
|
debug_print(INFO, "path_offset: %s", path_offset);
|
|
debug_print(INFO, "depth: %d", depth);
|
|
|
|
if (!node_ptr) return NULL;
|
|
|
|
if (path_offset >= path+path_len) {
|
|
free(path);
|
|
open_fs(node_ptr, flags);
|
|
return node_ptr;
|
|
}
|
|
fs_node_t *node_next = NULL;
|
|
for (; depth < path_depth; ++depth) {
|
|
/* Search the active directory for the requested directory */
|
|
debug_print(INFO, "... Searching for %s", path_offset);
|
|
node_next = finddir_fs(node_ptr, path_offset);
|
|
free(node_ptr); /* Always a clone or an unopened thing */
|
|
node_ptr = node_next;
|
|
if (!node_ptr) {
|
|
/* We failed to find the requested directory */
|
|
free((void *)path);
|
|
return NULL;
|
|
}
|
|
/*
|
|
* This test is a little complicated, but we basically always resolve symlinks in the
|
|
* of a path (like /home/symlink/file) even if O_NOFOLLOW and O_PATH are set. If we are
|
|
* on the leaf of the path then we will look at those flags and act accordingly
|
|
*/
|
|
if ((node_ptr->flags & FS_SYMLINK) &&
|
|
!((flags & O_NOFOLLOW) && (flags & O_PATH) && depth == path_depth - 1)) {
|
|
/* This ensures we don't return a path when NOFOLLOW is requested but PATH
|
|
* isn't passed.
|
|
*/
|
|
debug_print(NOTICE, "resolving symlink at %s", node_ptr->name);
|
|
if ((flags & O_NOFOLLOW) && depth == path_depth - 1) {
|
|
/* TODO(gerow): should probably be setting errno from this */
|
|
debug_print(NOTICE, "Refusing to follow final entry for open with O_NOFOLLOW for %s.", node_ptr->name);
|
|
free((void *)path);
|
|
free(node_ptr);
|
|
return NULL;
|
|
}
|
|
if (symlink_depth >= MAX_SYMLINK_DEPTH) {
|
|
/* TODO(gerow): should probably be setting errno from this */
|
|
debug_print(WARNING, "Reached max symlink depth on %s.", node_ptr->name);
|
|
free((void *)path);
|
|
free(node_ptr);
|
|
return NULL;
|
|
}
|
|
/*
|
|
* This may actually be big enough that we wouldn't want to allocate it on
|
|
* the stack, especially considering this function is called recursively
|
|
*/
|
|
char symlink_buf[MAX_SYMLINK_SIZE];
|
|
int len = readlink_fs(node_ptr, symlink_buf, sizeof(symlink_buf));
|
|
if (len < 0) {
|
|
/* TODO(gerow): should probably be setting errno from this */
|
|
debug_print(WARNING, "Got error %d from symlink for %s.", len, node_ptr->name);
|
|
free((void *)path);
|
|
free(node_ptr);
|
|
return NULL;
|
|
}
|
|
if (symlink_buf[len] != '\0') {
|
|
/* TODO(gerow): should probably be setting errno from this */
|
|
debug_print(WARNING, "readlink for %s doesn't end in a null pointer. That's weird...", node_ptr->name);
|
|
free((void *)path);
|
|
free(node_ptr);
|
|
return NULL;
|
|
}
|
|
fs_node_t * old_node_ptr = node_ptr;
|
|
/* Rebuild our path up to this point. This is hella hacky. */
|
|
char * relpath = malloc(path_len + 1);
|
|
char * ptr = relpath;
|
|
memcpy(relpath, path, path_len + 1);
|
|
for (unsigned int i = 0; i < depth; i++) {
|
|
while(*ptr != '\0') {
|
|
ptr++;
|
|
}
|
|
*ptr = PATH_SEPARATOR;
|
|
}
|
|
node_ptr = kopen_recur(symlink_buf, 0, symlink_depth + 1, relpath);
|
|
free(relpath);
|
|
free(old_node_ptr);
|
|
if (!node_ptr) {
|
|
/* Dangling symlink? */
|
|
debug_print(WARNING, "Failed to open symlink path %s. Perhaps it's a dangling symlink?", symlink_buf);
|
|
free((void *)path);
|
|
return NULL;
|
|
}
|
|
}
|
|
if (depth == path_depth - 1) {
|
|
/* We found the file and are done, open the node */
|
|
open_fs(node_ptr, flags);
|
|
free((void *)path);
|
|
return node_ptr;
|
|
}
|
|
/* We are still searching... */
|
|
path_offset += strlen(path_offset) + 1;
|
|
}
|
|
debug_print(INFO, "- Not found.");
|
|
/* We failed to find the requested file, but our loop terminated. */
|
|
free((void *)path);
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* kopen: Open a file by name.
|
|
*
|
|
* Explore the file system tree to find the appropriate node for
|
|
* for a given path. The path can be relative to the working directory
|
|
* and will be canonicalized by the kernel.
|
|
*
|
|
* @param filename Filename to open
|
|
* @param flags Flag bits for read/write mode.
|
|
* @returns A file system node element that the caller can free.
|
|
*/
|
|
fs_node_t *kopen(char *filename, uint32_t flags) {
|
|
debug_print(NOTICE, "kopen(%s)", filename);
|
|
|
|
return kopen_recur(filename, flags, 0, (char *)(current_process->wd_name));
|
|
}
|
|
|