600 lines
13 KiB
C
600 lines
13 KiB
C
/*
|
|
* 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);
|