/* * Squashfs - a compressed read only filesystem for Linux * * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008 * Phillip Lougher * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2, * or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. * * id.c */ /* * This file implements code to handle uids and gids. * * For space efficiency regular files store uid and gid indexes, which are * converted to 32-bit uids/gids using an id look up table. This table is * stored compressed into metadata blocks. A second index table is used to * locate these. This second index table for speed of access (and because it * is small) is read at mount time and cached in memory. */ #include #include #include #include "squashfs_fs.h" #include "squashfs_fs_sb.h" #include "squashfs.h" /* * Map uid/gid index into real 32-bit uid/gid using the id look up table */ int squashfs_get_id(struct super_block *sb, unsigned int index, unsigned int *id) { struct squashfs_sb_info *msblk = sb->s_fs_info; int block = SQUASHFS_ID_BLOCK(index); int offset = SQUASHFS_ID_BLOCK_OFFSET(index); u64 start_block = le64_to_cpu(msblk->id_table[block]); __le32 disk_id; int err; err = squashfs_read_metadata(sb, &disk_id, &start_block, &offset, sizeof(disk_id)); if (err < 0) return err; *id = le32_to_cpu(disk_id); return 0; } /* * Read uncompressed id lookup table indexes from disk into memory */ __le64 *squashfs_read_id_index_table(struct super_block *sb, u64 id_table_start, u64 next_table, unsigned short no_ids) { unsigned int length = SQUASHFS_ID_BLOCK_BYTES(no_ids); __le64 *table; TRACE("In read_id_index_table, length %d\n", length); /* Sanity check values */ /* there should always be at least one id */ if (no_ids == 0) return ERR_PTR(-EINVAL); /* * length bytes should not extend into the next table - this check * also traps instances where id_table_start is incorrectly larger * than the next table start */ if (id_table_start + length > next_table) return ERR_PTR(-EINVAL); table = squashfs_read_table(sb, id_table_start, length); /* * table[0] points to the first id lookup table metadata block, this * should be less than id_table_start */ if (!IS_ERR(table) && le64_to_cpu(table[0]) >= id_table_start) { kfree(table); return ERR_PTR(-EINVAL); } return table; } gi/linux/net-next.git/log/?h=nds-private-remove&id=6d5496483f5eb7b4da2e83c7b2149a21ad412d96'>root/tools/perf/Documentation/perf-bench.txt
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