original development tree for Linux kernel GTP module; now long in mainline.
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/*
* proc/fs/generic.c --- generic routines for the proc-fs
*
* This file contains generic proc-fs routines for handling
* directories and files.
*
* Copyright (C) 1991, 1992 Linus Torvalds.
* Copyright (C) 1997 Theodore Ts'o
*/
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/printk.h>
#include <linux/mount.h>
#include <linux/init.h>
#include <linux/idr.h>
#include <linux/namei.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <asm/uaccess.h>
#include "internal.h"
DEFINE_SPINLOCK(proc_subdir_lock);
static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
{
if (de->namelen != len)
return 0;
return !memcmp(name, de->name, len);
}
static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
{
struct inode *inode = dentry->d_inode;
struct proc_dir_entry *de = PDE(inode);
int error;
error = inode_change_ok(inode, iattr);
if (error)
return error;
setattr_copy(inode, iattr);
mark_inode_dirty(inode);
de->uid = inode->i_uid;
de->gid = inode->i_gid;
de->mode = inode->i_mode;
return 0;
}
static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
struct kstat *stat)
{
struct inode *inode = dentry->d_inode;
struct proc_dir_entry *de = PROC_I(inode)->pde;
if (de && de->nlink)
set_nlink(inode, de->nlink);
generic_fillattr(inode, stat);
return 0;
}
static const struct inode_operations proc_file_inode_operations = {
.setattr = proc_notify_change,
};
/*
* This function parses a name such as "tty/driver/serial", and
* returns the struct proc_dir_entry for "/proc/tty/driver", and
* returns "serial" in residual.
*/
static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
const char **residual)
{
const char *cp = name, *next;
struct proc_dir_entry *de;
unsigned int len;
de = *ret;
if (!de)
de = &proc_root;
while (1) {
next = strchr(cp, '/');
if (!next)
break;
len = next - cp;
for (de = de->subdir; de ; de = de->next) {
if (proc_match(len, cp, de))
break;
}
if (!de) {
WARN(1, "name '%s'\n", name);
return -ENOENT;
}
cp += len + 1;
}
*residual = cp;
*ret = de;
return 0;
}
static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
const char **residual)
{
int rv;
spin_lock(&proc_subdir_lock);
rv = __xlate_proc_name(name, ret, residual);
spin_unlock(&proc_subdir_lock);
return rv;
}
static DEFINE_IDA(proc_inum_ida);
static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
#define PROC_DYNAMIC_FIRST 0xF0000000U
/*
* Return an inode number between PROC_DYNAMIC_FIRST and
* 0xffffffff, or zero on failure.
*/
int proc_alloc_inum(unsigned int *inum)
{
unsigned int i;
int error;
retry:
if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
return -ENOMEM;
spin_lock_irq(&proc_inum_lock);
error = ida_get_new(&proc_inum_ida, &i);
spin_unlock_irq(&proc_inum_lock);
if (error == -EAGAIN)
goto retry;
else if (error)
return error;
if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
spin_lock_irq(&proc_inum_lock);
ida_remove(&proc_inum_ida, i);
spin_unlock_irq(&proc_inum_lock);
return -ENOSPC;
}
*inum = PROC_DYNAMIC_FIRST + i;
return 0;
}
void proc_free_inum(unsigned int inum)
{
unsigned long flags;
spin_lock_irqsave(&proc_inum_lock, flags);
ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
spin_unlock_irqrestore(&proc_inum_lock, flags);
}
static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
{
nd_set_link(nd, __PDE_DATA(dentry->d_inode));
return NULL;
}
static const struct inode_operations proc_link_inode_operations = {
.readlink = generic_readlink,
.follow_link = proc_follow_link,
};
/*
* Don't create negative dentries here, return -ENOENT by hand
* instead.
*/
struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
struct dentry *dentry)
{
struct inode *inode;
spin_lock(&proc_subdir_lock);
for (de = de->subdir; de ; de = de->next) {
if (de->namelen != dentry->d_name.len)
continue;
if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
pde_get(de);
spin_unlock(&proc_subdir_lock);
inode = proc_get_inode(dir->i_sb, de);
if (!inode)
return ERR_PTR(-ENOMEM);
d_set_d_op(dentry, &simple_dentry_operations);
d_add(dentry, inode);
return NULL;
}
}
spin_unlock(&proc_subdir_lock);
return ERR_PTR(-ENOENT);
}
struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
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
* continue with the <pid> entries..
*
* Note that the VFS-layer doesn't care about the return
* value of the readdir() call, as long as it's non-negative
* for success..
*/
int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
struct dir_context *ctx)
{
int i;
if (!dir_emit_dots(file, ctx))
return 0;
spin_lock(&proc_subdir_lock);
de = de->subdir;
i = ctx->pos - 2;
for (;;) {
if (!de) {
spin_unlock(&proc_subdir_lock);
return 0;
}
if (!i)
break;
de = de->next;
i--;
}
do {
struct proc_dir_entry *next;
pde_get(de);
spin_unlock(&proc_subdir_lock);
if (!dir_emit(ctx, de->name, de->namelen,
de->low_ino, de->mode >> 12)) {
pde_put(de);
return 0;
}
spin_lock(&proc_subdir_lock);
ctx->pos++;
next = de->next;
pde_put(de);
de = next;
} while (de);
spin_unlock(&proc_subdir_lock);
return 1;
}
int proc_readdir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
return proc_readdir_de(PDE(inode), file, ctx);
}
/*
* These are the generic /proc directory operations. They
* use the in-memory "struct proc_dir_entry" tree to parse
* the /proc directory.
*/
static const struct file_operations proc_dir_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate = proc_readdir,
};
/*
* proc directories can do almost nothing..
*/
static const struct inode_operations proc_dir_inode_operations = {
.lookup = proc_lookup,
.getattr = proc_getattr,
.setattr = proc_notify_change,
};
static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
{
struct proc_dir_entry *tmp;
int ret;
ret = proc_alloc_inum(&dp->low_ino);
if (ret)
return ret;
if (S_ISDIR(dp->mode)) {
dp->proc_fops = &proc_dir_operations;
dp->proc_iops = &proc_dir_inode_operations;
dir->nlink++;
} else if (S_ISLNK(dp->mode)) {
dp->proc_iops = &proc_link_inode_operations;
} else if (S_ISREG(dp->mode)) {
BUG_ON(dp->proc_fops == NULL);
dp->proc_iops = &proc_file_inode_operations;
} else {
WARN_ON(1);
return -EINVAL;
}
spin_lock(&proc_subdir_lock);
for (tmp = dir->subdir; tmp; tmp = tmp->next)
if (strcmp(tmp->name, dp->name) == 0) {
WARN(1, "proc_dir_entry '%s/%s' already registered\n",
dir->name, dp->name);
break;
}
dp->next = dir->subdir;
dp->parent = dir;
dir->subdir = dp;
spin_unlock(&proc_subdir_lock);
return 0;
}
static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
const char *name,
umode_t mode,
nlink_t nlink)
{
struct proc_dir_entry *ent = NULL;
const char *fn = name;
unsigned int len;
/* make sure name is valid */
if (!name || !strlen(name))
goto out;
if (xlate_proc_name(name, parent, &fn) != 0)
goto out;
/* At this point there must not be any '/' characters beyond *fn */
if (strchr(fn, '/'))
goto out;
len = strlen(fn);
ent = kzalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
if (!ent)
goto out;
memcpy(ent->name, fn, len + 1);
ent->namelen = len;
ent->mode = mode;
ent->nlink = nlink;
atomic_set(&ent->count, 1);
spin_lock_init(&ent->pde_unload_lock);
INIT_LIST_HEAD(&ent->pde_openers);
out:
return ent;
}
struct proc_dir_entry *proc_symlink(const char *name,
struct proc_dir_entry *parent, const char *dest)
{
struct proc_dir_entry *ent;
ent = __proc_create(&parent, name,
(S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
if (ent) {
ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
if (ent->data) {
strcpy((char*)ent->data,dest);
if (proc_register(parent, ent) < 0) {
kfree(ent->data);
kfree(ent);
ent = NULL;
}
} else {
kfree(ent);
ent = NULL;
}
}
return ent;
}
EXPORT_SYMBOL(proc_symlink);
struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
struct proc_dir_entry *parent, void *data)
{
struct proc_dir_entry *ent;
if (mode == 0)
mode = S_IRUGO | S_IXUGO;
ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
if (ent) {
ent->data = data;
if (proc_register(parent, ent) < 0) {
kfree(ent);
ent = NULL;
}
}
return ent;
}
EXPORT_SYMBOL_GPL(proc_mkdir_data);
struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
struct proc_dir_entry *parent)
{
return proc_mkdir_data(name, mode, parent, NULL);
}
EXPORT_SYMBOL(proc_mkdir_mode);
struct proc_dir_entry *proc_mkdir(const char *name,
struct proc_dir_entry *parent)
{
return proc_mkdir_data(name, 0, parent, NULL);
}
EXPORT_SYMBOL(proc_mkdir);
struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
struct proc_dir_entry *parent,
const struct file_operations *proc_fops,
void *data)
{
struct proc_dir_entry *pde;
if ((mode & S_IFMT) == 0)
mode |= S_IFREG;
if (!S_ISREG(mode)) {
WARN_ON(1); /* use proc_mkdir() */
return NULL;
}
if ((mode & S_IALLUGO) == 0)
mode |= S_IRUGO;
pde = __proc_create(&parent, name, mode, 1);
if (!pde)
goto out;
pde->proc_fops = proc_fops;
pde->data = data;
if (proc_register(parent, pde) < 0)
goto out_free;
return pde;
out_free:
kfree(pde);
out:
return NULL;
}
EXPORT_SYMBOL(proc_create_data);
void proc_set_size(struct proc_dir_entry *de, loff_t size)
{
de->size = size;
}
EXPORT_SYMBOL(proc_set_size);
void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
{
de->uid = uid;
de->gid = gid;
}
EXPORT_SYMBOL(proc_set_user);
static void free_proc_entry(struct proc_dir_entry *de)
{
proc_free_inum(de->low_ino);
if (S_ISLNK(de->mode))
kfree(de->data);
kfree(de);
}
void pde_put(struct proc_dir_entry *pde)
{
if (atomic_dec_and_test(&pde->count))
free_proc_entry(pde);
}
/*
* Remove a /proc entry and free it if it's not currently in use.
*/
void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
{
struct proc_dir_entry **p;
struct proc_dir_entry *de = NULL;
const char *fn = name;
unsigned int len;
spin_lock(&proc_subdir_lock);
if (__xlate_proc_name(name, &parent, &fn) != 0) {
spin_unlock(&proc_subdir_lock);
return;
}
len = strlen(fn);
for (p = &parent->subdir; *p; p=&(*p)->next ) {
if (proc_match(len, fn, *p)) {
de = *p;
*p = de->next;
de->next = NULL;
break;
}
}
spin_unlock(&proc_subdir_lock);
if (!de) {
WARN(1, "name '%s'\n", name);
return;
}
proc_entry_rundown(de);
if (S_ISDIR(de->mode))
parent->nlink--;
de->nlink = 0;
WARN(de->subdir, "%s: removing non-empty directory "
"'%s/%s', leaking at least '%s'\n", __func__,
de->parent->name, de->name, de->subdir->name);
pde_put(de);
}
EXPORT_SYMBOL(remove_proc_entry);
int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
{
struct proc_dir_entry **p;
struct proc_dir_entry *root = NULL, *de, *next;
const char *fn = name;
unsigned int len;
spin_lock(&proc_subdir_lock);
if (__xlate_proc_name(name, &parent, &fn) != 0) {
spin_unlock(&proc_subdir_lock);
return -ENOENT;
}
len = strlen(fn);
for (p = &parent->subdir; *p; p=&(*p)->next ) {
if (proc_match(len, fn, *p)) {
root = *p;
*p = root->next;
root->next = NULL;
break;
}
}
if (!root) {
spin_unlock(&proc_subdir_lock);
return -ENOENT;
}
de = root;
while (1) {
next = de->subdir;
if (next) {
de->subdir = next->next;
next->next = NULL;
de = next;
continue;
}
spin_unlock(&proc_subdir_lock);
proc_entry_rundown(de);
next = de->parent;
if (S_ISDIR(de->mode))
next->nlink--;
de->nlink = 0;
if (de == root)
break;
pde_put(de);
spin_lock(&proc_subdir_lock);
de = next;
}
pde_put(root);
return 0;
}
EXPORT_SYMBOL(remove_proc_subtree);
void *proc_get_parent_data(const struct inode *inode)
{
struct proc_dir_entry *de = PDE(inode);
return de->parent->data;
}
EXPORT_SYMBOL_GPL(proc_get_parent_data);
void proc_remove(struct proc_dir_entry *de)
{
if (de)
remove_proc_subtree(de->name, de->parent);
}
EXPORT_SYMBOL(proc_remove);
void *PDE_DATA(const struct inode *inode)
{
return __PDE_DATA(inode);
}
EXPORT_SYMBOL(PDE_DATA);