forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
117 lines
3.2 KiB
117 lines
3.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* QNX4 file system, Linux implementation. |
|
* |
|
* Version : 0.2.1 |
|
* |
|
* Using parts of the xiafs filesystem. |
|
* |
|
* History : |
|
* |
|
* 28-05-1998 by Richard Frowijn : first release. |
|
* 20-06-1998 by Frank Denis : Linux 2.1.99+ & dcache support. |
|
*/ |
|
|
|
#include <linux/buffer_head.h> |
|
#include "qnx4.h" |
|
|
|
/* |
|
* A qnx4 directory entry is an inode entry or link info |
|
* depending on the status field in the last byte. The |
|
* first byte is where the name start either way, and a |
|
* zero means it's empty. |
|
* |
|
* Also, due to a bug in gcc, we don't want to use the |
|
* real (differently sized) name arrays in the inode and |
|
* link entries, but always the 'de_name[]' one in the |
|
* fake struct entry. |
|
* |
|
* See |
|
* |
|
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c6 |
|
* |
|
* for details, but basically gcc will take the size of the |
|
* 'name' array from one of the used union entries randomly. |
|
* |
|
* This use of 'de_name[]' (48 bytes) avoids the false positive |
|
* warnings that would happen if gcc decides to use 'inode.di_name' |
|
* (16 bytes) even when the pointer and size were to come from |
|
* 'link.dl_name' (48 bytes). |
|
* |
|
* In all cases the actual name pointer itself is the same, it's |
|
* only the gcc internal 'what is the size of this field' logic |
|
* that can get confused. |
|
*/ |
|
union qnx4_directory_entry { |
|
struct { |
|
const char de_name[48]; |
|
u8 de_pad[15]; |
|
u8 de_status; |
|
}; |
|
struct qnx4_inode_entry inode; |
|
struct qnx4_link_info link; |
|
}; |
|
|
|
static int qnx4_readdir(struct file *file, struct dir_context *ctx) |
|
{ |
|
struct inode *inode = file_inode(file); |
|
unsigned int offset; |
|
struct buffer_head *bh; |
|
unsigned long blknum; |
|
int ix, ino; |
|
int size; |
|
|
|
QNX4DEBUG((KERN_INFO "qnx4_readdir:i_size = %ld\n", (long) inode->i_size)); |
|
QNX4DEBUG((KERN_INFO "pos = %ld\n", (long) ctx->pos)); |
|
|
|
while (ctx->pos < inode->i_size) { |
|
blknum = qnx4_block_map(inode, ctx->pos >> QNX4_BLOCK_SIZE_BITS); |
|
bh = sb_bread(inode->i_sb, blknum); |
|
if (bh == NULL) { |
|
printk(KERN_ERR "qnx4_readdir: bread failed (%ld)\n", blknum); |
|
return 0; |
|
} |
|
ix = (ctx->pos >> QNX4_DIR_ENTRY_SIZE_BITS) % QNX4_INODES_PER_BLOCK; |
|
for (; ix < QNX4_INODES_PER_BLOCK; ix++, ctx->pos += QNX4_DIR_ENTRY_SIZE) { |
|
union qnx4_directory_entry *de; |
|
|
|
offset = ix * QNX4_DIR_ENTRY_SIZE; |
|
de = (union qnx4_directory_entry *) (bh->b_data + offset); |
|
|
|
if (!de->de_name[0]) |
|
continue; |
|
if (!(de->de_status & (QNX4_FILE_USED|QNX4_FILE_LINK))) |
|
continue; |
|
if (!(de->de_status & QNX4_FILE_LINK)) { |
|
size = sizeof(de->inode.di_fname); |
|
ino = blknum * QNX4_INODES_PER_BLOCK + ix - 1; |
|
} else { |
|
size = sizeof(de->link.dl_fname); |
|
ino = ( le32_to_cpu(de->link.dl_inode_blk) - 1 ) * |
|
QNX4_INODES_PER_BLOCK + |
|
de->link.dl_inode_ndx; |
|
} |
|
size = strnlen(de->de_name, size); |
|
QNX4DEBUG((KERN_INFO "qnx4_readdir:%.*s\n", size, name)); |
|
if (!dir_emit(ctx, de->de_name, size, ino, DT_UNKNOWN)) { |
|
brelse(bh); |
|
return 0; |
|
} |
|
} |
|
brelse(bh); |
|
} |
|
return 0; |
|
} |
|
|
|
const struct file_operations qnx4_dir_operations = |
|
{ |
|
.llseek = generic_file_llseek, |
|
.read = generic_read_dir, |
|
.iterate_shared = qnx4_readdir, |
|
.fsync = generic_file_fsync, |
|
}; |
|
|
|
const struct inode_operations qnx4_dir_inode_operations = |
|
{ |
|
.lookup = qnx4_lookup, |
|
};
|
|
|