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author | Al Viro <viro@zeniv.linux.org.uk> | 2014-11-18 23:38:21 -0500 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2014-12-10 21:32:15 -0500 |
commit | bd9b51e79cb0b8bc00a7e0076a4a8963ca4a797c (patch) | |
tree | bee3cc60bfbe1d7f837826bf495c0cf92747404b /net/nonet.c | |
parent | 1f55a6ec940fb45e3edaa52b6e9fc40cf8e18dcb (diff) | |
download | linux-bd9b51e79cb0b8bc00a7e0076a4a8963ca4a797c.tar.bz2 |
make default ->i_fop have ->open() fail with ENXIO
As it is, default ->i_fop has NULL ->open() (along with all other methods).
The only case where it matters is reopening (via procfs symlink) a file that
didn't get its ->f_op from ->i_fop - anything else will have ->i_fop assigned
to something sane (default would fail on read/write/ioctl/etc.).
Unfortunately, such case exists - alloc_file() users, especially
anon_get_file() ones. There we have tons of opened files of very different
kinds sharing the same inode. As the result, attempt to reopen those via
procfs succeeds and you get a descriptor you can't do anything with.
Moreover, in case of sockets we set ->i_fop that will only be used
on such reopen attempts - and put a failing ->open() into it to make sure
those do not succeed.
It would be simpler to put such ->open() into default ->i_fop and leave
it unchanged both for anon inode (as we do anyway) and for socket ones. Result:
* everything going through do_dentry_open() works as it used to
* sock_no_open() kludge is gone
* attempts to reopen anon-inode files fail as they really ought to
* ditto for aio_private_file()
* ditto for perfmon - this one actually tried to imitate sock_no_open()
trick, but failed to set ->i_fop, so in the current tree reopens succeed and
yield completely useless descriptor. Intent clearly had been to fail with
-ENXIO on such reopens; now it actually does.
* everything else that used alloc_file() keeps working - it has ->i_fop
set for its inodes anyway
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'net/nonet.c')
-rw-r--r-- | net/nonet.c | 26 |
1 files changed, 0 insertions, 26 deletions
diff --git a/net/nonet.c b/net/nonet.c deleted file mode 100644 index b1a73fda9c12..000000000000 --- a/net/nonet.c +++ /dev/null @@ -1,26 +0,0 @@ -/* - * net/nonet.c - * - * Dummy functions to allow us to configure network support entirely - * out of the kernel. - * - * Distributed under the terms of the GNU GPL version 2. - * Copyright (c) Matthew Wilcox 2003 - */ - -#include <linux/module.h> -#include <linux/errno.h> -#include <linux/fs.h> -#include <linux/init.h> -#include <linux/kernel.h> - -static int sock_no_open(struct inode *irrelevant, struct file *dontcare) -{ - return -ENXIO; -} - -const struct file_operations bad_sock_fops = { - .owner = THIS_MODULE, - .open = sock_no_open, - .llseek = noop_llseek, -}; |