cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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symlink.c (1235B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * symlink.c
      4 *
      5 * Copyright (c) 1999 Al Smith
      6 *
      7 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
      8 */
      9
     10#include <linux/string.h>
     11#include <linux/pagemap.h>
     12#include <linux/buffer_head.h>
     13#include "efs.h"
     14
     15static int efs_symlink_read_folio(struct file *file, struct folio *folio)
     16{
     17	struct page *page = &folio->page;
     18	char *link = page_address(page);
     19	struct buffer_head * bh;
     20	struct inode * inode = page->mapping->host;
     21	efs_block_t size = inode->i_size;
     22	int err;
     23  
     24	err = -ENAMETOOLONG;
     25	if (size > 2 * EFS_BLOCKSIZE)
     26		goto fail;
     27  
     28	/* read first 512 bytes of link target */
     29	err = -EIO;
     30	bh = sb_bread(inode->i_sb, efs_bmap(inode, 0));
     31	if (!bh)
     32		goto fail;
     33	memcpy(link, bh->b_data, (size > EFS_BLOCKSIZE) ? EFS_BLOCKSIZE : size);
     34	brelse(bh);
     35	if (size > EFS_BLOCKSIZE) {
     36		bh = sb_bread(inode->i_sb, efs_bmap(inode, 1));
     37		if (!bh)
     38			goto fail;
     39		memcpy(link + EFS_BLOCKSIZE, bh->b_data, size - EFS_BLOCKSIZE);
     40		brelse(bh);
     41	}
     42	link[size] = '\0';
     43	SetPageUptodate(page);
     44	unlock_page(page);
     45	return 0;
     46fail:
     47	SetPageError(page);
     48	unlock_page(page);
     49	return err;
     50}
     51
     52const struct address_space_operations efs_symlink_aops = {
     53	.read_folio	= efs_symlink_read_folio
     54};