/* vi: set sw=4 ts=4: *//* * namei.c --- ext2fs directory lookup operations * * Copyright (C) 1993, 1994, 1994, 1995 Theodore Ts'o. * * %Begin-Header% * This file may be redistributed under the terms of the GNU Public * License. * %End-Header% */#include <stdio.h>#include <string.h>#if HAVE_UNISTD_H#include <unistd.h>#endif/* #define NAMEI_DEBUG */#include "ext2_fs.h"#include "ext2fs.h"static errcode_t open_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t base,			    const char *pathname, size_t pathlen, int follow,			    int link_count, char *buf, ext2_ino_t *res_inode);static errcode_t follow_link(ext2_filsys fs, ext2_ino_t root, ext2_ino_t dir,			     ext2_ino_t inode, int link_count,			     char *buf, ext2_ino_t *res_inode){	char *pathname;	char *buffer = 0;	errcode_t retval;	struct ext2_inode ei;#ifdef NAMEI_DEBUG	printf("follow_link: root=%lu, dir=%lu, inode=%lu, lc=%d\n",	       root, dir, inode, link_count);#endif	retval = ext2fs_read_inode (fs, inode, &ei);	if (retval) return retval;	if (!LINUX_S_ISLNK (ei.i_mode)) {		*res_inode = inode;		return 0;	}	if (link_count++ > 5) {		return EXT2_ET_SYMLINK_LOOP;	}	if (ext2fs_inode_data_blocks(fs,&ei)) {		retval = ext2fs_get_mem(fs->blocksize, &buffer);		if (retval)			return retval;		retval = io_channel_read_blk(fs->io, ei.i_block[0], 1, buffer);		if (retval) {			ext2fs_free_mem(&buffer);			return retval;		}		pathname = buffer;	} else		pathname = (char *)&(ei.i_block[0]);	retval = open_namei(fs, root, dir, pathname, ei.i_size, 1,			    link_count, buf, res_inode);	ext2fs_free_mem(&buffer);	return retval;}/* * This routine interprets a pathname in the context of the current * directory and the root directory, and returns the inode of the * containing directory, and a pointer to the filename of the file * (pointing into the pathname) and the length of the filename. */static errcode_t dir_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t dir,			   const char *pathname, int pathlen,			   int link_count, char *buf,			   const char **name, int *namelen,			   ext2_ino_t *res_inode){	char c;	const char *thisname;	int len;	ext2_ino_t inode;	errcode_t retval;	if ((c = *pathname) == '/') {		dir = root;		pathname++;		pathlen--;	}	while (1) {		thisname = pathname;		for (len=0; --pathlen >= 0;len++) {			c = *(pathname++);			if (c == '/')				break;		}		if (pathlen < 0)			break;		retval = ext2fs_lookup (fs, dir, thisname, len, buf, &inode);		if (retval) return retval;		retval = follow_link (fs, root, dir, inode,				      link_count, buf, &dir);		if (retval) return retval;	}	*name = thisname;	*namelen = len;	*res_inode = dir;	return 0;}static errcode_t open_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t base,			    const char *pathname, size_t pathlen, int follow,			    int link_count, char *buf, ext2_ino_t *res_inode){	const char *basename;	int namelen;	ext2_ino_t dir, inode;	errcode_t retval;#ifdef NAMEI_DEBUG	printf("open_namei: root=%lu, dir=%lu, path=%*s, lc=%d\n",	       root, base, pathlen, pathname, link_count);#endif	retval = dir_namei(fs, root, base, pathname, pathlen,			   link_count, buf, &basename, &namelen, &dir);	if (retval) return retval;	if (!namelen) {                     /* special case: '/usr/' etc */		*res_inode=dir;		return 0;	}	retval = ext2fs_lookup (fs, dir, basename, namelen, buf, &inode);	if (retval)		return retval;	if (follow) {		retval = follow_link(fs, root, dir, inode, link_count,				     buf, &inode);		if (retval)			return retval;	}#ifdef NAMEI_DEBUG	printf("open_namei: (link_count=%d) returns %lu\n",	       link_count, inode);#endif	*res_inode = inode;	return 0;}errcode_t ext2fs_namei(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,		       const char *name, ext2_ino_t *inode){	char *buf;	errcode_t retval;	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);	retval = ext2fs_get_mem(fs->blocksize, &buf);	if (retval)		return retval;	retval = open_namei(fs, root, cwd, name, strlen(name), 0, 0,			    buf, inode);	ext2fs_free_mem(&buf);	return retval;}errcode_t ext2fs_namei_follow(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,			      const char *name, ext2_ino_t *inode){	char *buf;	errcode_t retval;	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);	retval = ext2fs_get_mem(fs->blocksize, &buf);	if (retval)		return retval;	retval = open_namei(fs, root, cwd, name, strlen(name), 1, 0,			    buf, inode);	ext2fs_free_mem(&buf);	return retval;}errcode_t ext2fs_follow_link(ext2_filsys fs, ext2_ino_t root, ext2_ino_t cwd,			ext2_ino_t inode, ext2_ino_t *res_inode){	char *buf;	errcode_t retval;	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);	retval = ext2fs_get_mem(fs->blocksize, &buf);	if (retval)		return retval;	retval = follow_link(fs, root, cwd, inode, 0, buf, res_inode);	ext2fs_free_mem(&buf);	return retval;}