fs/isofs/dir.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  *  linux/fs/isofs/dir.c
  *
  *  (C) 1992, 1993, 1994  Eric Youngdale Modified for ISO 9660 filesystem.
  *
  *  (C) 1991  Linus Torvalds - minix filesystem
  *
  *  Steve Beynon		       : Missing last directory entries fixed
  *  (stephen@askone.demon.co.uk)      : 21st June 1996
  *
  *  isofs directory handling functions
  */
 #include <linux/gfp.h>
 #include "isofs.h"

 int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode)
 {
 	char * old = de->name;
 	int len = de->name_len[0];
 	int i;

 	for (i = 0; i < len; i++) {
 		unsigned char c = old[i];
 		if (!c)
 			break;

 		if (c >= 'A' && c <= 'Z')
 			c |= 0x20;	/* lower case */

 		/* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
 		if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
 			break;

 		/* Drop trailing ';1' */
 		if (c == ';' && i == len - 2 && old[i + 1] == '1')
 			break;

 		/* Convert remaining ';' to '.' */
 		/* Also '/' to '.' (broken Acorn-generated ISO9660 images) */
 		if (c == ';' || c == '/')
 			c = '.';

 		new[i] = c;
 	}
 	return i;
 }

 /* Acorn extensions written by Matthew Wilcox <willy@bofh.ai> 1998 */
 int get_acorn_filename(struct iso_directory_record *de,
 			    char *retname, struct inode *inode)
 {
 	int std;
 	unsigned char *chr;
 	int retnamlen = isofs_name_translate(de, retname, inode);

 	if (retnamlen == 0)
 		return 0;
 	std = sizeof(struct iso_directory_record) + de->name_len[0];
 	if (std & 1)
 		std++;
 	if (de->length[0] - std != 32)
 		return retnamlen;
 	chr = ((unsigned char *) de) + std;
 	if (strncmp(chr, "ARCHIMEDES", 10))
 		return retnamlen;
 	if ((*retname == '_') && ((chr[19] & 1) == 1))
 		*retname = '!';
 	if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
 		&& ((chr[12] & 0xf0) == 0xf0)) {
 		retname[retnamlen] = ',';
 		sprintf(retname+retnamlen+1, "%3.3x",
 			((chr[12] & 0xf) << 8) | chr[11]);
 		retnamlen += 4;
 	}
 	return retnamlen;
 }

 /*
  * This should _really_ be cleaned up some day..
  */
 static int do_isofs_readdir(struct inode *inode, struct file *file,
 		struct dir_context *ctx,
 		char *tmpname, struct iso_directory_record *tmpde)
 {
 	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
 	unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
 	unsigned long block, offset, block_saved, offset_saved;
 	unsigned long inode_number = 0;	/* Quiet GCC */
 	struct buffer_head *bh = NULL;
 	int len;
 	int map;
 	int first_de = 1;
 	char *p = NULL;		/* Quiet GCC */
 	struct iso_directory_record *de;
 	struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);

 	offset = ctx->pos & (bufsize - 1);
 	block = ctx->pos >> bufbits;

 	while (ctx->pos < inode->i_size) {
 		int de_len;

 		if (!bh) {
 			bh = isofs_bread(inode, block);
 			if (!bh)
 				return 0;
 		}

 		de = (struct iso_directory_record *) (bh->b_data + offset);

 		de_len = *(unsigned char *)de;

 		/*
 		 * If the length byte is zero, we should move on to the next
 		 * CDROM sector.  If we are at the end of the directory, we
 		 * kick out of the while loop.
 		 */

 		if (de_len == 0) {
 			brelse(bh);
 			bh = NULL;
 			ctx->pos = (ctx->pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
 			block = ctx->pos >> bufbits;
 			offset = 0;
 			continue;
 		}

 		block_saved = block;
 		offset_saved = offset;
 		offset += de_len;

 		/* Make sure we have a full directory entry */
 		if (offset >= bufsize) {
 			int slop = bufsize - offset + de_len;
 			memcpy(tmpde, de, slop);
 			offset &= bufsize - 1;
 			block++;
 			brelse(bh);
 			bh = NULL;
 			if (offset) {
 				bh = isofs_bread(inode, block);
 				if (!bh)
 					return 0;
 				memcpy((void *) tmpde + slop, bh->b_data, offset);
 			}
 			de = tmpde;
 		}
 		/* Basic sanity check, whether name doesn't exceed dir entry */
 		if (de_len < de->name_len[0] +
 					sizeof(struct iso_directory_record)) {
 			printk(KERN_NOTICE "iso9660: Corrupted directory entry"
 			       " in block %lu of inode %lu\n", block,
 			       inode->i_ino);
 			return -EIO;
 		}

 		if (first_de) {
 			isofs_normalize_block_and_offset(de,
 							&block_saved,
 							&offset_saved);
 			inode_number = isofs_get_ino(block_saved,
 							offset_saved, bufbits);
 		}

 		if (de->flags[-sbi->s_high_sierra] & 0x80) {
 			first_de = 0;
 			ctx->pos += de_len;
 			continue;
 		}
 		first_de = 1;

 		/* Handle the case of the '.' directory */
 		if (de->name_len[0] == 1 && de->name[0] == 0) {
 			if (!dir_emit_dot(file, ctx))
 				break;
 			ctx->pos += de_len;
 			continue;
 		}

 		len = 0;

 		/* Handle the case of the '..' directory */
 		if (de->name_len[0] == 1 && de->name[0] == 1) {
 			if (!dir_emit_dotdot(file, ctx))
 				break;
 			ctx->pos += de_len;
 			continue;
 		}

 		/* Handle everything else.  Do name translation if there
 		   is no Rock Ridge NM field. */

 		/*
 		 * Do not report hidden files if so instructed, or associated
 		 * files unless instructed to do so
 		 */
 		if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
 		    (!sbi->s_showassoc &&
 				(de->flags[-sbi->s_high_sierra] & 4))) {
 			ctx->pos += de_len;
 			continue;
 		}

 		map = 1;
 		if (sbi->s_rock) {
 			len = get_rock_ridge_filename(de, tmpname, inode);
 			if (len != 0) {		/* may be -1 */
 				p = tmpname;
 				map = 0;
 			}
 		}
 		if (map) {
 #ifdef CONFIG_JOLIET
 			if (sbi->s_joliet_level) {
 				len = get_joliet_filename(de, tmpname, inode);
 				p = tmpname;
 			} else
 #endif
 			if (sbi->s_mapping == 'a') {
 				len = get_acorn_filename(de, tmpname, inode);
 				p = tmpname;
 			} else
 			if (sbi->s_mapping == 'n') {
 				len = isofs_name_translate(de, tmpname, inode);
 				p = tmpname;
 			} else {
 				p = de->name;
 				len = de->name_len[0];
 			}
 		}
 		if (len > 0) {
 			if (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN))
 				break;
 		}
 		ctx->pos += de_len;

 		continue;
 	}
 	if (bh)
 		brelse(bh);
 	return 0;
 }

 /*
  * Handle allocation of temporary space for name translation and
  * handling split directory entries.. The real work is done by
  * "do_isofs_readdir()".
  */
 static int isofs_readdir(struct file *file, struct dir_context *ctx)
 {
 	int result;
 	char *tmpname;
 	struct iso_directory_record *tmpde;
 	struct inode *inode = file_inode(file);

 	tmpname = (char *)__get_free_page(GFP_KERNEL);
 	if (tmpname == NULL)
 		return -ENOMEM;

 	tmpde = (struct iso_directory_record *) (tmpname+1024);

 	result = do_isofs_readdir(inode, file, ctx, tmpname, tmpde);

 	free_page((unsigned long) tmpname);
 	return result;
 }

 const struct file_operations isofs_dir_operations =
 {
 	.llseek = generic_file_llseek,
 	.read = generic_read_dir,
 	.iterate_shared = isofs_readdir,
 };

 /*
  * directories can handle most operations...
  */
 const struct inode_operations isofs_dir_inode_operations =
 {
 	.lookup = isofs_lookup,
 };
	// SPDX-License-Identifier: GPL-2.0
	/*
	* linux/fs/isofs/dir.c
	*
	* (C) 1992, 1993, 1994 Eric Youngdale Modified for ISO 9660 filesystem.
	*
	* (C) 1991 Linus Torvalds - minix filesystem
	*
	* Steve Beynon : Missing last directory entries fixed
	* (stephen@askone.demon.co.uk) : 21st June 1996
	*
	* isofs directory handling functions
	*/
	#include <linux/gfp.h>
	#include "isofs.h"

	int isofs_name_translate(struct iso_directory_record de, char new, struct inode *inode)
	{
	char * old = de->name;
	int len = de->name_len[0];
	int i;

	for (i = 0; i < len; i++) {
	unsigned char c = old[i];
	if (!c)
	break;

	if (c >= 'A' && c <= 'Z')
	c \|= 0x20; /* lower case */

	/* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
	if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
	break;

	/* Drop trailing ';1' */
	if (c == ';' && i == len - 2 && old[i + 1] == '1')
	break;

	/* Convert remaining ';' to '.' */
	/* Also '/' to '.' (broken Acorn-generated ISO9660 images) */
	if (c == ';' \|\| c == '/')
	c = '.';

	new[i] = c;
	}
	return i;
	}

	/* Acorn extensions written by Matthew Wilcox <willy@bofh.ai> 1998 */
	int get_acorn_filename(struct iso_directory_record *de,
	char retname, struct inode inode)
	{
	int std;
	unsigned char *chr;
	int retnamlen = isofs_name_translate(de, retname, inode);

	if (retnamlen == 0)
	return 0;
	std = sizeof(struct iso_directory_record) + de->name_len[0];
	if (std & 1)
	std++;
	if (de->length[0] - std != 32)
	return retnamlen;
	chr = ((unsigned char *) de) + std;
	if (strncmp(chr, "ARCHIMEDES", 10))
	return retnamlen;
	if ((*retname == '_') && ((chr[19] & 1) == 1))
	*retname = '!';
	if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
	&& ((chr[12] & 0xf0) == 0xf0)) {
	retname[retnamlen] = ',';
	sprintf(retname+retnamlen+1, "%3.3x",
	((chr[12] & 0xf) << 8) \| chr[11]);
	retnamlen += 4;
	}
	return retnamlen;
	}

	/*
	* This should _really_ be cleaned up some day..
	*/
	static int do_isofs_readdir(struct inode inode, struct file file,
	struct dir_context *ctx,
	char tmpname, struct iso_directory_record tmpde)
	{
	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
	unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
	unsigned long block, offset, block_saved, offset_saved;
	unsigned long inode_number = 0; /* Quiet GCC */
	struct buffer_head *bh = NULL;
	int len;
	int map;
	int first_de = 1;
	char p = NULL; / Quiet GCC */
	struct iso_directory_record *de;
	struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);

	offset = ctx->pos & (bufsize - 1);
	block = ctx->pos >> bufbits;

	while (ctx->pos < inode->i_size) {
	int de_len;

	if (!bh) {
	bh = isofs_bread(inode, block);
	if (!bh)
	return 0;
	}

	de = (struct iso_directory_record *) (bh->b_data + offset);

	de_len = (unsigned char )de;

	/*
	* If the length byte is zero, we should move on to the next
	* CDROM sector. If we are at the end of the directory, we
	* kick out of the while loop.
	*/

	if (de_len == 0) {
	brelse(bh);
	bh = NULL;
	ctx->pos = (ctx->pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
	block = ctx->pos >> bufbits;
	offset = 0;
	continue;
	}

	block_saved = block;
	offset_saved = offset;
	offset += de_len;

	/* Make sure we have a full directory entry */
	if (offset >= bufsize) {
	int slop = bufsize - offset + de_len;
	memcpy(tmpde, de, slop);
	offset &= bufsize - 1;
	block++;
	brelse(bh);
	bh = NULL;
	if (offset) {
	bh = isofs_bread(inode, block);
	if (!bh)
	return 0;
	memcpy((void *) tmpde + slop, bh->b_data, offset);
	}
	de = tmpde;
	}
	/* Basic sanity check, whether name doesn't exceed dir entry */
	if (de_len < de->name_len[0] +
	sizeof(struct iso_directory_record)) {
	printk(KERN_NOTICE "iso9660: Corrupted directory entry"
	" in block %lu of inode %lu\n", block,
	inode->i_ino);
	return -EIO;
	}

	if (first_de) {
	isofs_normalize_block_and_offset(de,
	&block_saved,
	&offset_saved);
	inode_number = isofs_get_ino(block_saved,
	offset_saved, bufbits);
	}

	if (de->flags[-sbi->s_high_sierra] & 0x80) {
	first_de = 0;
	ctx->pos += de_len;
	continue;
	}
	first_de = 1;

	/* Handle the case of the '.' directory */
	if (de->name_len[0] == 1 && de->name[0] == 0) {
	if (!dir_emit_dot(file, ctx))
	break;
	ctx->pos += de_len;
	continue;
	}

	len = 0;

	/* Handle the case of the '..' directory */
	if (de->name_len[0] == 1 && de->name[0] == 1) {
	if (!dir_emit_dotdot(file, ctx))
	break;
	ctx->pos += de_len;
	continue;
	}

	/* Handle everything else. Do name translation if there
	is no Rock Ridge NM field. */

	/*
	* Do not report hidden files if so instructed, or associated
	* files unless instructed to do so
	*/
	if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) \|\|
	(!sbi->s_showassoc &&
	(de->flags[-sbi->s_high_sierra] & 4))) {
	ctx->pos += de_len;
	continue;
	}

	map = 1;
	if (sbi->s_rock) {
	len = get_rock_ridge_filename(de, tmpname, inode);
	if (len != 0) { /* may be -1 */
	p = tmpname;
	map = 0;
	}
	}
	if (map) {
	#ifdef CONFIG_JOLIET
	if (sbi->s_joliet_level) {
	len = get_joliet_filename(de, tmpname, inode);
	p = tmpname;
	} else
	#endif
	if (sbi->s_mapping == 'a') {
	len = get_acorn_filename(de, tmpname, inode);
	p = tmpname;
	} else
	if (sbi->s_mapping == 'n') {
	len = isofs_name_translate(de, tmpname, inode);
	p = tmpname;
	} else {
	p = de->name;
	len = de->name_len[0];
	}
	}
	if (len > 0) {
	if (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN))
	break;
	}
	ctx->pos += de_len;

	continue;
	}
	if (bh)
	brelse(bh);
	return 0;
	}

	/*
	* Handle allocation of temporary space for name translation and
	* handling split directory entries.. The real work is done by
	* "do_isofs_readdir()".
	*/
	static int isofs_readdir(struct file file, struct dir_context ctx)
	{
	int result;
	char *tmpname;
	struct iso_directory_record *tmpde;
	struct inode *inode = file_inode(file);

	tmpname = (char *)__get_free_page(GFP_KERNEL);
	if (tmpname == NULL)
	return -ENOMEM;

	tmpde = (struct iso_directory_record *) (tmpname+1024);

	result = do_isofs_readdir(inode, file, ctx, tmpname, tmpde);

	free_page((unsigned long) tmpname);
	return result;
	}

	const struct file_operations isofs_dir_operations =
	{
	.llseek = generic_file_llseek,
	.read = generic_read_dir,
	.iterate_shared = isofs_readdir,
	};

	/*
	* directories can handle most operations...
	*/
	const struct inode_operations isofs_dir_inode_operations =
	{
	.lookup = isofs_lookup,
	};