Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * Squashfs - a compressed read only filesystem for Linux
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  * Phillip Lougher <phillip@squashfs.org.uk>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  * dir.c
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  * This file implements code to read directories from disk.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  * See namei.c for a description of directory organisation on disk.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/vfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #include "squashfs_fs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) #include "squashfs_fs_sb.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #include "squashfs_fs_i.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) #include "squashfs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) static const unsigned char squashfs_filetype_table[] = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 	DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_FIFO, DT_SOCK
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31)  * Lookup offset (f_pos) in the directory index, returning the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32)  * metadata block containing it.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34)  * If we get an error reading the index then return the part of the index
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35)  * (if any) we have managed to read - the index isn't essential, just
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36)  * quicker.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) static int get_dir_index_using_offset(struct super_block *sb,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 	u64 *next_block, int *next_offset, u64 index_start, int index_offset,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 	int i_count, u64 f_pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 	struct squashfs_sb_info *msblk = sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	int err, i, index, length = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 	unsigned int size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	struct squashfs_dir_index dir_index;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	TRACE("Entered get_dir_index_using_offset, i_count %d, f_pos %lld\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 					i_count, f_pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	 * Translate from external f_pos to the internal f_pos.  This
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 	 * is offset by 3 because we invent "." and ".." entries which are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	 * not actually stored in the directory.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 	if (f_pos <= 3)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 		return f_pos;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) 	f_pos -= 3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	for (i = 0; i < i_count; i++) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 		err = squashfs_read_metadata(sb, &dir_index, &index_start,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 				&index_offset, sizeof(dir_index));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 		if (err < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 		index = le32_to_cpu(dir_index.index);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 		if (index > f_pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 			/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 			 * Found the index we're looking for.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 			 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 		size = le32_to_cpu(dir_index.size) + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 		/* size should never be larger than SQUASHFS_NAME_LEN */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 		if (size > SQUASHFS_NAME_LEN)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 		err = squashfs_read_metadata(sb, NULL, &index_start,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 				&index_offset, size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 		if (err < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 		length = index;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 		*next_block = le32_to_cpu(dir_index.start_block) +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 					msblk->directory_table;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	*next_offset = (length + *next_offset) % SQUASHFS_METADATA_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 	 * Translate back from internal f_pos to external f_pos.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	return length + 3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) static int squashfs_readdir(struct file *file, struct dir_context *ctx)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	struct inode *inode = file_inode(file);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	u64 block = squashfs_i(inode)->start + msblk->directory_table;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	int offset = squashfs_i(inode)->offset, length, err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 	unsigned int inode_number, dir_count, size, type;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	struct squashfs_dir_header dirh;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	struct squashfs_dir_entry *dire;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 	TRACE("Entered squashfs_readdir [%llx:%x]\n", block, offset);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	dire = kmalloc(sizeof(*dire) + SQUASHFS_NAME_LEN + 1, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	if (dire == NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 		ERROR("Failed to allocate squashfs_dir_entry\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 		goto finish;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	 * Return "." and  ".." entries as the first two filenames in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	 * directory.  To maximise compression these two entries are not
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	 * stored in the directory, and so we invent them here.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	 * It also means that the external f_pos is offset by 3 from the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 	 * on-disk directory f_pos.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 	while (ctx->pos < 3) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 		char *name;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 		int i_ino;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 		if (ctx->pos == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 			name = ".";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 			size = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 			i_ino = inode->i_ino;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 		} else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 			name = "..";
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 			size = 2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 			i_ino = squashfs_i(inode)->parent;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		if (!dir_emit(ctx, name, size, i_ino,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 				squashfs_filetype_table[1]))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 			goto finish;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 		ctx->pos += size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	length = get_dir_index_using_offset(inode->i_sb, &block, &offset,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 				squashfs_i(inode)->dir_idx_start,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 				squashfs_i(inode)->dir_idx_offset,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 				squashfs_i(inode)->dir_idx_cnt,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 				ctx->pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	while (length < i_size_read(inode)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 		/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 		 * Read directory header
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 		err = squashfs_read_metadata(inode->i_sb, &dirh, &block,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 					&offset, sizeof(dirh));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 		if (err < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 			goto failed_read;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 		length += sizeof(dirh);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 		dir_count = le32_to_cpu(dirh.count) + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 		if (dir_count > SQUASHFS_DIR_COUNT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 			goto failed_read;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 		while (dir_count--) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 			/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 			 * Read directory entry.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 			 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 			err = squashfs_read_metadata(inode->i_sb, dire, &block,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 					&offset, sizeof(*dire));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 			if (err < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 				goto failed_read;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 			size = le16_to_cpu(dire->size) + 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 			/* size should never be larger than SQUASHFS_NAME_LEN */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 			if (size > SQUASHFS_NAME_LEN)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 				goto failed_read;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 			err = squashfs_read_metadata(inode->i_sb, dire->name,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 					&block, &offset, size);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 			if (err < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 				goto failed_read;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 			length += sizeof(*dire) + size;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 			if (ctx->pos >= length)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 				continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 			dire->name[size] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 			inode_number = le32_to_cpu(dirh.inode_number) +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 				((short) le16_to_cpu(dire->inode_number));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 			type = le16_to_cpu(dire->type);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 			if (type > SQUASHFS_MAX_DIR_TYPE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 				goto failed_read;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 			if (!dir_emit(ctx, dire->name, size,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 					inode_number,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 					squashfs_filetype_table[type]))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 				goto finish;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 			ctx->pos = length;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) finish:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	kfree(dire);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) failed_read:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	ERROR("Unable to read directory block [%llx:%x]\n", block, offset);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	kfree(dire);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) const struct file_operations squashfs_dir_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 	.read = generic_read_dir,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 	.iterate_shared = squashfs_readdir,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) 	.llseek = generic_file_llseek,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) };