path: root/fs/proc/generic.c
diff options
authorPavel Emelyanov <xemul@openvz.org>2008-03-07 11:08:40 -0800
committerDavid S. Miller <davem@davemloft.net>2008-03-07 11:08:40 -0800
commite9720acd728a46cb40daa52c99a979f7c4ff195c (patch)
tree01380f601384cf93f30dedb64afe80359fecb807 /fs/proc/generic.c
parent1ff82fe0024e8070c38346b8abc1ff09612dea4c (diff)
[NET]: Make /proc/net a symlink on /proc/self/net (v3)
Current /proc/net is done with so called "shadows", but current implementation is broken and has little chances to get fixed. The problem is that dentries subtree of /proc/net directory has fancy revalidation rules to make processes living in different net namespaces see different entries in /proc/net subtree, but currently, tasks see in the /proc/net subdir the contents of any other namespace, depending on who opened the file first. The proposed fix is to turn /proc/net into a symlink, which points to /proc/self/net, which in turn shows what previously was in /proc/net - the network-related info, from the net namespace the appropriate task lives in. # ls -l /proc/net lrwxrwxrwx 1 root root 8 Mar 5 15:17 /proc/net -> self/net In other words - this behaves like /proc/mounts, but unlike "mounts", "net" is not a file, but a directory. Changes from v2: * Fixed discrepancy of /proc/net nlink count and selinux labeling screwup pointed out by Stephen. To get the correct nlink count the ->getattr callback for /proc/net is overridden to read one from the net->proc_net entry. To make selinux still work the net->proc_net entry is initialized properly, i.e. with the "net" name and the proc_net parent. Selinux fixes are Acked-by: Stephen Smalley <sds@tycho.nsa.gov> Changes from v1: * Fixed a task_struct leak in get_proc_task_net, pointed out by Paul. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'fs/proc/generic.c')
1 files changed, 17 insertions, 9 deletions
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 68971e66cd4..a36ad3c75cf 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -377,15 +377,14 @@ static struct dentry_operations proc_dentry_operations =
* Don't create negative dentries here, return -ENOENT by hand
* instead.
-struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
+struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
+ struct dentry *dentry)
struct inode *inode = NULL;
- struct proc_dir_entry * de;
int error = -ENOENT;
- de = PDE(dir);
if (de) {
for (de = de->subdir; de ; de = de->next) {
if (de->namelen != dentry->d_name.len)
@@ -393,8 +392,6 @@ struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry, struct nam
if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
unsigned int ino;
- if (de->shadow_proc)
- de = de->shadow_proc(current, de);
ino = de->low_ino;
@@ -417,6 +414,12 @@ out_unlock:
return ERR_PTR(error);
+struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
+ struct nameidata *nd)
+ return proc_lookup_de(PDE(dir), dir, dentry);
* This returns non-zero if at EOF, so that the /proc
* root directory can use this and check if it should
@@ -426,10 +429,9 @@ out_unlock:
* value of the readdir() call, as long as it's non-negative
* for success..
-int proc_readdir(struct file * filp,
- void * dirent, filldir_t filldir)
+int proc_readdir_de(struct proc_dir_entry *de, struct file *filp, void *dirent,
+ filldir_t filldir)
- struct proc_dir_entry * de;
unsigned int ino;
int i;
struct inode *inode = filp->f_path.dentry->d_inode;
@@ -438,7 +440,6 @@ int proc_readdir(struct file * filp,
ino = inode->i_ino;
- de = PDE(inode);
if (!de) {
ret = -EINVAL;
goto out;
@@ -499,6 +500,13 @@ out: unlock_kernel();
return ret;
+int proc_readdir(struct file *filp, void *dirent, filldir_t filldir)
+ struct inode *inode = filp->f_path.dentry->d_inode;
+ return proc_readdir_de(PDE(inode), filp, dirent, filldir);
* These are the generic /proc directory operations. They
* use the in-memory "struct proc_dir_entry" tree to parse