[PATCH] proc: Fix /proc/net directory listings.

From: Eric W . Biederman
Date: Tue Nov 20 2007 - 21:36:05 EST

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Having proc dynamically display the contents of /proc/net is
hard. So make life simpler by capturing the network namespace
when we mount proc and only displaying that network namespace.

---
fs/proc/base.c | 8 ++--
fs/proc/generic.c | 4 ++-
fs/proc/internal.h | 13 +++++++
fs/proc/proc_net.c | 89 ++++-------------------------------------------
fs/proc/root.c | 50 ++++++++++++++++++--------
include/linux/proc_fs.h | 4 ++
6 files changed, 66 insertions(+), 102 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index aeaf0d0..9d4f06a 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2395,7 +2395,7 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct
if (tgid == ~0U)
goto out;

- ns = dentry->d_sb->s_fs_info;
+ ns = proc_sbi(dentry->d_sb)->pid_ns;
rcu_read_lock();
task = find_task_by_pid_ns(tgid, ns);
if (task)
@@ -2476,7 +2476,7 @@ int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir)
goto out;
}

- ns = filp->f_dentry->d_sb->s_fs_info;
+ ns = proc_sbi(filp->f_dentry->d_sb)->pid_ns;
tgid = filp->f_pos - TGID_OFFSET;
for (task = next_tgid(tgid, ns);
task;
@@ -2615,7 +2615,7 @@ static struct dentry *proc_task_lookup(struct inode *dir, struct dentry * dentry
if (tid == ~0U)
goto out;

- ns = dentry->d_sb->s_fs_info;
+ ns = proc_sbi(dentry->d_sb)->pid_ns;
rcu_read_lock();
task = find_task_by_pid_ns(tid, ns);
if (task)
@@ -2758,7 +2758,7 @@ static int proc_task_readdir(struct file * filp, void * dirent, filldir_t filldi
/* f_version caches the tgid value that the last readdir call couldn't
* return. lseek aka telldir automagically resets f_version to 0.
*/
- ns = filp->f_dentry->d_sb->s_fs_info;
+ ns = proc_sbi(filp->f_dentry->d_sb)->pid_ns;
tid = (int)filp->f_version;
filp->f_version = 0;
for (task = first_tid(leader, tid, pos - 2, ns);
diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 1bdb624..b58f0ec 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -398,7 +398,9 @@ struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry, struct nam
continue;
if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
unsigned int ino = de->low_ino;
-
+
+ if (de->shadow_proc)
+ de = de->shadow_proc(dentry->d_sb, de);
de_get(de);
spin_unlock(&proc_subdir_lock);
error = -EINVAL;
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 1820eb2..a26f115 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -11,6 +11,18 @@

#include <linux/proc_fs.h>

+struct pid_namespace;
+struct net;
+struct proc_sb_info {
+ struct pid_namespace *pid_ns;
+ struct net *net_ns;
+};
+
+static inline struct proc_sb_info *proc_sbi(struct super_block *sb)
+{
+ return sb->s_fs_info;
+}
+
#ifdef CONFIG_PROC_SYSCTL
extern int proc_sys_init(void);
#else
@@ -78,3 +90,4 @@ static inline int proc_fd(struct inode *inode)
{
return PROC_I(inode)->fd;
}
+
diff --git a/fs/proc/proc_net.c b/fs/proc/proc_net.c
index 131f9c6..8a82e29 100644
--- a/fs/proc/proc_net.c
+++ b/fs/proc/proc_net.c
@@ -50,89 +50,15 @@ struct net *get_proc_net(const struct inode *inode)
}
EXPORT_SYMBOL_GPL(get_proc_net);

-static struct proc_dir_entry *proc_net_shadow;
+static struct proc_dir_entry *shadow_pde;

-static struct dentry *proc_net_shadow_dentry(struct dentry *parent,
- struct proc_dir_entry *de)
+static struct proc_dir_entry *proc_net_shadow(struct super_block *sb,
+ struct proc_dir_entry *de)
{
- struct dentry *shadow = NULL;
- struct inode *inode;
- if (!de)
- goto out;
- de_get(de);
- inode = proc_get_inode(parent->d_inode->i_sb, de->low_ino, de);
- if (!inode)
- goto out_de_put;
- shadow = d_alloc_name(parent, de->name);
- if (!shadow)
- goto out_iput;
- shadow->d_op = parent->d_op; /* proc_dentry_operations */
- d_instantiate(shadow, inode);
-out:
- return shadow;
-out_iput:
- iput(inode);
-out_de_put:
- de_put(de);
- goto out;
-}
-
-static void *proc_net_follow_link(struct dentry *parent, struct nameidata *nd)
-{
- struct net *net = current->nsproxy->net_ns;
- struct dentry *shadow;
- shadow = proc_net_shadow_dentry(parent, net->proc_net);
- if (!shadow)
- return ERR_PTR(-ENOENT);
-
- dput(nd->dentry);
- /* My dentry count is 1 and that should be enough as the
- * shadow dentry is thrown away immediately.
- */
- nd->dentry = shadow;
- return NULL;
+ struct proc_sb_info *sbi = proc_sbi(sb);
+ return sbi->net_ns->proc_net;
}

-static struct dentry *proc_net_lookup(struct inode *dir, struct dentry *dentry,
- struct nameidata *nd)
-{
- struct net *net = current->nsproxy->net_ns;
- struct dentry *shadow;
-
- shadow = proc_net_shadow_dentry(nd->dentry, net->proc_net);
- if (!shadow)
- return ERR_PTR(-ENOENT);
-
- dput(nd->dentry);
- nd->dentry = shadow;
-
- return shadow->d_inode->i_op->lookup(shadow->d_inode, dentry, nd);
-}
-
-static int proc_net_setattr(struct dentry *dentry, struct iattr *iattr)
-{
- struct net *net = current->nsproxy->net_ns;
- struct dentry *shadow;
- int ret;
-
- shadow = proc_net_shadow_dentry(dentry->d_parent, net->proc_net);
- if (!shadow)
- return -ENOENT;
- ret = shadow->d_inode->i_op->setattr(shadow, iattr);
- dput(shadow);
- return ret;
-}
-
-static const struct file_operations proc_net_dir_operations = {
- .read = generic_read_dir,
-};
-
-static struct inode_operations proc_net_dir_inode_operations = {
- .follow_link = proc_net_follow_link,
- .lookup = proc_net_lookup,
- .setattr = proc_net_setattr,
-};
-
static __net_init int proc_net_ns_init(struct net *net)
{
struct proc_dir_entry *root, *netd, *net_statd;
@@ -185,9 +111,8 @@ static struct pernet_operations __net_initdata proc_net_ns_ops = {

int __init proc_net_init(void)
{
- proc_net_shadow = proc_mkdir("net", NULL);
- proc_net_shadow->proc_iops = &proc_net_dir_inode_operations;
- proc_net_shadow->proc_fops = &proc_net_dir_operations;
+ shadow_pde = proc_mkdir("net", NULL);
+ shadow_pde->shadow_proc = proc_net_shadow;

return register_pernet_subsys(&proc_net_ns_ops);
}
diff --git a/fs/proc/root.c b/fs/proc/root.c
index ec9cb3b..e60ac83 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -19,6 +19,7 @@
#include <linux/smp_lock.h>
#include <linux/mount.h>
#include <linux/pid_namespace.h>
+#include <net/net_namespace.h>

#include "internal.h"

@@ -26,15 +27,23 @@ struct proc_dir_entry *proc_bus, *proc_root_fs, *proc_root_driver;

static int proc_test_super(struct super_block *sb, void *data)
{
- return sb->s_fs_info == data;
+ struct proc_sb_info *sbi = proc_sbi(sb), *info = data;
+ return (sbi->pid_ns == info->pid_ns) &&
+ (sbi->net_ns == info->net_ns);
}

static int proc_set_super(struct super_block *sb, void *data)
{
- struct pid_namespace *ns;
-
- ns = (struct pid_namespace *)data;
- sb->s_fs_info = get_pid_ns(ns);
+
+ struct proc_sb_info *new, *info = data;
+
+ new = kzalloc(sizeof(*new), GFP_KERNEL);
+ if (!new)
+ return -ENOMEM;
+ *new = *info;
+ get_pid_ns(new->pid_ns);
+ get_net(new->net_ns);
+ sb->s_fs_info = new;
return set_anon_super(sb, NULL);
}

@@ -43,7 +52,7 @@ static int proc_get_sb(struct file_system_type *fs_type,
{
int err;
struct super_block *sb;
- struct pid_namespace *ns;
+ struct proc_sb_info info, *sbi;
struct proc_inode *ei;

if (proc_mnt) {
@@ -57,12 +66,14 @@ static int proc_get_sb(struct file_system_type *fs_type,
ei->pid = find_get_pid(1);
}

+ info.pid_ns = current->nsproxy->pid_ns;
+ info.net_ns = current->nsproxy->net_ns;
if (flags & MS_KERNMOUNT)
- ns = (struct pid_namespace *)data;
+ sbi = data;
else
- ns = current->nsproxy->pid_ns;
+ sbi = &info;

- sb = sget(fs_type, proc_test_super, proc_set_super, ns);
+ sb = sget(fs_type, proc_test_super, proc_set_super, sbi);
if (IS_ERR(sb))
return PTR_ERR(sb);

@@ -78,12 +89,13 @@ static int proc_get_sb(struct file_system_type *fs_type,
ei = PROC_I(sb->s_root->d_inode);
if (!ei->pid) {
rcu_read_lock();
- ei->pid = get_pid(find_pid_ns(1, ns));
+ ei->pid = get_pid(find_pid_ns(1, sbi->pid_ns));
rcu_read_unlock();
}

sb->s_flags |= MS_ACTIVE;
- ns->proc_mnt = mnt;
+ if (!sbi->pid_ns->proc_mnt)
+ sbi->pid_ns->proc_mnt = mnt;
}

return simple_set_mnt(mnt, sb);
@@ -91,11 +103,13 @@ static int proc_get_sb(struct file_system_type *fs_type,

static void proc_kill_sb(struct super_block *sb)
{
- struct pid_namespace *ns;
+ struct proc_sb_info *sbi;

- ns = (struct pid_namespace *)sb->s_fs_info;
+ sbi = proc_sbi(sb);
kill_anon_super(sb);
- put_pid_ns(ns);
+ put_pid_ns(sbi->pid_ns);
+ put_net(sbi->net_ns);
+ kfree(sbi);
}

static struct file_system_type proc_fs_type = {
@@ -106,13 +120,16 @@ static struct file_system_type proc_fs_type = {

void __init proc_root_init(void)
{
+ struct proc_sb_info info;
int err = proc_init_inodecache();
if (err)
return;
err = register_filesystem(&proc_fs_type);
if (err)
return;
- proc_mnt = kern_mount_data(&proc_fs_type, &init_pid_ns);
+ info.pid_ns = &init_pid_ns;
+ info.net_ns = current->nsproxy->net_ns;
+ proc_mnt = kern_mount_data(&proc_fs_type, &info);
err = PTR_ERR(proc_mnt);
if (IS_ERR(proc_mnt)) {
unregister_filesystem(&proc_fs_type);
@@ -214,8 +231,11 @@ struct proc_dir_entry proc_root = {

int pid_ns_prepare_proc(struct pid_namespace *ns)
{
+ struct proc_sb_info info;
struct vfsmount *mnt;

+ info.pid_ns = ns;
+ info.net_ns = current->nsproxy->net_ns;
mnt = kern_mount_data(&proc_fs_type, ns);
if (IS_ERR(mnt))
return PTR_ERR(mnt);
diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 2b3c1d8..c22c558 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -48,6 +48,9 @@ typedef int (read_proc_t)(char *page, char **start, off_t off,
typedef int (write_proc_t)(struct file *file, const char __user *buffer,
unsigned long count, void *data);
typedef int (get_info_t)(char *, char **, off_t, int);
+struct proc_dir_entry;
+typedef struct proc_dir_entry *(shadow_proc_t)(struct super_block *sb,
+ struct proc_dir_entry *pde);

struct proc_dir_entry {
unsigned int low_ino;
@@ -79,6 +82,7 @@ struct proc_dir_entry {
int pde_users; /* number of callers into module in progress */
spinlock_t pde_unload_lock; /* proc_fops checks and pde_users bumps */
struct completion *pde_unload_completion;
+ shadow_proc_t *shadow_proc;
};

struct kcore_list {
--
1.5.3.rc6.17.g1911

-
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Next message: 小崎資広: "Re: [PATCH 4/6] Use two zonelist that are filtered by GFP mask"
Previous message: Walt H: "Re: CONFIG_IRQBALANCE for 64-bit x86 ?"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]