linux-hardened/fs/9p/vfs_file.c
Eric Van Hensbergen 2e4bef41a0 9p: fix O_APPEND in legacy mode
The legacy protocol's open operation doesn't handle an append operation
(it is expected that the client take care of it).  We were incorrectly
passing the extended protocol's flag through even in legacy mode.  This
was reported in bugzilla report #10689.  This patch fixes the problem
by disallowing extended protocol open modes from being passed in legacy
mode and implemented append functionality on the client side by adding
a seek after the open.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
2008-07-03 09:59:03 -05:00

201 lines
4.9 KiB
C

/*
* linux/fs/9p/vfs_file.c
*
* This file contians vfs file ops for 9P2000.
*
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* 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:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/inet.h>
#include <linux/list.h>
#include <asm/uaccess.h>
#include <linux/idr.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
static const struct file_operations v9fs_cached_file_operations;
/**
* v9fs_file_open - open a file (or directory)
* @inode: inode to be opened
* @file: file being opened
*
*/
int v9fs_file_open(struct inode *inode, struct file *file)
{
int err;
struct v9fs_session_info *v9ses;
struct p9_fid *fid;
int omode;
P9_DPRINTK(P9_DEBUG_VFS, "inode: %p file: %p \n", inode, file);
v9ses = v9fs_inode2v9ses(inode);
omode = v9fs_uflags2omode(file->f_flags, v9fs_extended(v9ses));
fid = file->private_data;
if (!fid) {
fid = v9fs_fid_clone(file->f_path.dentry);
if (IS_ERR(fid))
return PTR_ERR(fid);
err = p9_client_open(fid, omode);
if (err < 0) {
p9_client_clunk(fid);
return err;
}
if (omode & P9_OTRUNC) {
inode->i_size = 0;
inode->i_blocks = 0;
}
if ((file->f_flags & O_APPEND) && (!v9fs_extended(v9ses)))
generic_file_llseek(file, 0, SEEK_END);
}
file->private_data = fid;
if ((fid->qid.version) && (v9ses->cache)) {
P9_DPRINTK(P9_DEBUG_VFS, "cached");
/* enable cached file options */
if(file->f_op == &v9fs_file_operations)
file->f_op = &v9fs_cached_file_operations;
}
return 0;
}
/**
* v9fs_file_lock - lock a file (or directory)
* @filp: file to be locked
* @cmd: lock command
* @fl: file lock structure
*
* Bugs: this looks like a local only lock, we should extend into 9P
* by using open exclusive
*/
static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
{
int res = 0;
struct inode *inode = filp->f_path.dentry->d_inode;
P9_DPRINTK(P9_DEBUG_VFS, "filp: %p lock: %p\n", filp, fl);
/* No mandatory locks */
if (__mandatory_lock(inode))
return -ENOLCK;
if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
filemap_write_and_wait(inode->i_mapping);
invalidate_mapping_pages(&inode->i_data, 0, -1);
}
return res;
}
/**
* v9fs_file_read - read from a file
* @filp: file pointer to read
* @data: data buffer to read data into
* @count: size of buffer
* @offset: offset at which to read data
*
*/
static ssize_t
v9fs_file_read(struct file *filp, char __user * data, size_t count,
loff_t * offset)
{
int ret;
struct p9_fid *fid;
P9_DPRINTK(P9_DEBUG_VFS, "\n");
fid = filp->private_data;
ret = p9_client_uread(fid, data, *offset, count);
if (ret > 0)
*offset += ret;
return ret;
}
/**
* v9fs_file_write - write to a file
* @filp: file pointer to write
* @data: data buffer to write data from
* @count: size of buffer
* @offset: offset at which to write data
*
*/
static ssize_t
v9fs_file_write(struct file *filp, const char __user * data,
size_t count, loff_t * offset)
{
int ret;
struct p9_fid *fid;
struct inode *inode = filp->f_path.dentry->d_inode;
P9_DPRINTK(P9_DEBUG_VFS, "data %p count %d offset %x\n", data,
(int)count, (int)*offset);
fid = filp->private_data;
ret = p9_client_uwrite(fid, data, *offset, count);
if (ret > 0) {
invalidate_inode_pages2_range(inode->i_mapping, *offset,
*offset+ret);
*offset += ret;
}
if (*offset > inode->i_size) {
inode->i_size = *offset;
inode->i_blocks = (inode->i_size + 512 - 1) >> 9;
}
return ret;
}
static const struct file_operations v9fs_cached_file_operations = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.aio_read = generic_file_aio_read,
.write = v9fs_file_write,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock,
.mmap = generic_file_readonly_mmap,
};
const struct file_operations v9fs_file_operations = {
.llseek = generic_file_llseek,
.read = v9fs_file_read,
.write = v9fs_file_write,
.open = v9fs_file_open,
.release = v9fs_dir_release,
.lock = v9fs_file_lock,
.mmap = generic_file_readonly_mmap,
};