// 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, };