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linux-sg2042/fs/proc/generic.c

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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/cache.h>
#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/namei.h>
#include <linux/slab.h>
#include <linux/printk.h>
#include <linux/mount.h>
#include <linux/init.h>
#include <linux/idr.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/uaccess.h>
#include <linux/seq_file.h>
#include "internal.h"
static DEFINE_RWLOCK(proc_subdir_lock);
struct kmem_cache *proc_dir_entry_cache __ro_after_init;
void pde_free(struct proc_dir_entry *pde)
{
if (S_ISLNK(pde->mode))
kfree(pde->data);
if (pde->name != pde->inline_name)
kfree(pde->name);
kmem_cache_free(proc_dir_entry_cache, pde);
}
static int proc_match(const char *name, struct proc_dir_entry *de, unsigned int len)
{
if (len < de->namelen)
return -1;
if (len > de->namelen)
return 1;
return memcmp(name, de->name, len);
}
static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
{
return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
subdir_node);
}
static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
{
return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry,
subdir_node);
}
static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
const char *name,
unsigned int len)
{
struct rb_node *node = dir->subdir.rb_node;
while (node) {
struct proc_dir_entry *de = rb_entry(node,
struct proc_dir_entry,
subdir_node);
int result = proc_match(name, de, len);
if (result < 0)
node = node->rb_left;
else if (result > 0)
node = node->rb_right;
else
return de;
}
return NULL;
}
static bool pde_subdir_insert(struct proc_dir_entry *dir,
struct proc_dir_entry *de)
{
struct rb_root *root = &dir->subdir;
struct rb_node **new = &root->rb_node, *parent = NULL;
/* Figure out where to put new node */
while (*new) {
struct proc_dir_entry *this = rb_entry(*new,
struct proc_dir_entry,
subdir_node);
int result = proc_match(de->name, this, de->namelen);
parent = *new;
if (result < 0)
new = &(*new)->rb_left;
else if (result > 0)
new = &(*new)->rb_right;
else
return false;
}
/* Add new node and rebalance tree. */
rb_link_node(&de->subdir_node, parent, new);
rb_insert_color(&de->subdir_node, root);
return true;
}
static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
{
struct inode *inode = d_inode(dentry);
struct proc_dir_entry *de = PDE(inode);
int error;
error = setattr_prepare(dentry, iattr);
if (error)
return error;
setattr_copy(inode, iattr);
mark_inode_dirty(inode);
proc_set_user(de, inode->i_uid, inode->i_gid);
de->mode = inode->i_mode;
return 0;
}
static int proc_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int query_flags)
{
struct inode *inode = d_inode(path->dentry);
struct proc_dir_entry *de = PDE(inode);
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;
de = pde_subdir_find(de, cp, len);
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;
read_lock(&proc_subdir_lock);
rv = __xlate_proc_name(name, ret, residual);
read_unlock(&proc_subdir_lock);
return rv;
}
static DEFINE_IDA(proc_inum_ida);
#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)
{
int i;
i = ida_simple_get(&proc_inum_ida, 0, UINT_MAX - PROC_DYNAMIC_FIRST + 1,
GFP_KERNEL);
if (i < 0)
return i;
*inum = PROC_DYNAMIC_FIRST + (unsigned int)i;
return 0;
}
void proc_free_inum(unsigned int inum)
{
ida_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
}
static int proc_misc_d_revalidate(struct dentry *dentry, unsigned int flags)
{
if (flags & LOOKUP_RCU)
return -ECHILD;
if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0)
return 0; /* revalidate */
return 1;
}
static int proc_misc_d_delete(const struct dentry *dentry)
{
return atomic_read(&PDE(d_inode(dentry))->in_use) < 0;
}
static const struct dentry_operations proc_misc_dentry_ops = {
.d_revalidate = proc_misc_d_revalidate,
.d_delete = proc_misc_d_delete,
};
/*
* Don't create negative dentries here, return -ENOENT by hand
* instead.
*/
struct dentry *proc_lookup_de(struct inode *dir, struct dentry *dentry,
struct proc_dir_entry *de)
{
struct inode *inode;
read_lock(&proc_subdir_lock);
de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
if (de) {
pde_get(de);
read_unlock(&proc_subdir_lock);
inode = proc_get_inode(dir->i_sb, de);
if (!inode)
return ERR_PTR(-ENOMEM);
d_set_d_op(dentry, &proc_misc_dentry_ops);
return d_splice_alias(inode, dentry);
}
read_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(dir, dentry, PDE(dir));
}
/*
* 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 file *file, struct dir_context *ctx,
struct proc_dir_entry *de)
{
int i;
if (!dir_emit_dots(file, ctx))
return 0;
i = ctx->pos - 2;
read_lock(&proc_subdir_lock);
de = pde_subdir_first(de);
for (;;) {
if (!de) {
read_unlock(&proc_subdir_lock);
return 0;
}
if (!i)
break;
de = pde_subdir_next(de);
i--;
}
do {
struct proc_dir_entry *next;
pde_get(de);
read_unlock(&proc_subdir_lock);
if (!dir_emit(ctx, de->name, de->namelen,
de->low_ino, de->mode >> 12)) {
pde_put(de);
return 0;
}
ctx->pos++;
read_lock(&proc_subdir_lock);
next = pde_subdir_next(de);
pde_put(de);
de = next;
} while (de);
read_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(file, ctx, PDE(inode));
}
/*
* 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_shared = 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,
};
/* returns the registered entry, or frees dp and returns NULL on failure */
struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
struct proc_dir_entry *dp)
{
if (proc_alloc_inum(&dp->low_ino))
goto out_free_entry;
write_lock(&proc_subdir_lock);
dp->parent = dir;
if (pde_subdir_insert(dir, dp) == false) {
WARN(1, "proc_dir_entry '%s/%s' already registered\n",
dir->name, dp->name);
write_unlock(&proc_subdir_lock);
goto out_free_inum;
}
write_unlock(&proc_subdir_lock);
return dp;
out_free_inum:
proc_free_inum(dp->low_ino);
out_free_entry:
pde_free(dp);
return NULL;
}
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;
struct qstr qstr;
if (xlate_proc_name(name, parent, &fn) != 0)
goto out;
qstr.name = fn;
qstr.len = strlen(fn);
if (qstr.len == 0 || qstr.len >= 256) {
WARN(1, "name len %u\n", qstr.len);
return NULL;
}
if (qstr.len == 1 && fn[0] == '.') {
WARN(1, "name '.'\n");
return NULL;
}
if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
WARN(1, "name '..'\n");
return NULL;
}
if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
WARN(1, "create '/proc/%s' by hand\n", qstr.name);
return NULL;
}
if (is_empty_pde(*parent)) {
WARN(1, "attempt to add to permanently empty directory");
return NULL;
}
ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
if (!ent)
goto out;
if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {
ent->name = ent->inline_name;
} else {
ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);
if (!ent->name) {
pde_free(ent);
return NULL;
}
}
memcpy(ent->name, fn, qstr.len + 1);
ent->namelen = qstr.len;
ent->mode = mode;
ent->nlink = nlink;
ent->subdir = RB_ROOT;
refcount_set(&ent->refcnt, 1);
spin_lock_init(&ent->pde_unload_lock);
INIT_LIST_HEAD(&ent->pde_openers);
proc_set_user(ent, (*parent)->uid, (*parent)->gid);
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);
ent->proc_iops = &proc_link_inode_operations;
ent = proc_register(parent, ent);
} else {
pde_free(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;
ent->proc_fops = &proc_dir_operations;
ent->proc_iops = &proc_dir_inode_operations;
parent->nlink++;
ent = proc_register(parent, ent);
if (!ent)
parent->nlink--;
}
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_mount_point(const char *name)
{
umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
struct proc_dir_entry *ent, *parent = NULL;
ent = __proc_create(&parent, name, mode, 2);
if (ent) {
ent->data = NULL;
ent->proc_fops = NULL;
ent->proc_iops = NULL;
parent->nlink++;
ent = proc_register(parent, ent);
if (!ent)
parent->nlink--;
}
return ent;
}
EXPORT_SYMBOL(proc_create_mount_point);
struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
struct proc_dir_entry **parent, void *data)
{
struct proc_dir_entry *p;
if ((mode & S_IFMT) == 0)
mode |= S_IFREG;
if ((mode & S_IALLUGO) == 0)
mode |= S_IRUGO;
if (WARN_ON_ONCE(!S_ISREG(mode)))
return NULL;
p = __proc_create(parent, name, mode, 1);
if (p) {
p->proc_iops = &proc_file_inode_operations;
p->data = data;
}
return p;
}
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 *p;
BUG_ON(proc_fops == NULL);
p = proc_create_reg(name, mode, &parent, data);
if (!p)
return NULL;
p->proc_fops = proc_fops;
return proc_register(parent, p);
}
EXPORT_SYMBOL(proc_create_data);
struct proc_dir_entry *proc_create(const char *name, umode_t mode,
struct proc_dir_entry *parent,
const struct file_operations *proc_fops)
{
return proc_create_data(name, mode, parent, proc_fops, NULL);
}
EXPORT_SYMBOL(proc_create);
static int proc_seq_open(struct inode *inode, struct file *file)
{
struct proc_dir_entry *de = PDE(inode);
if (de->state_size)
return seq_open_private(file, de->seq_ops, de->state_size);
return seq_open(file, de->seq_ops);
}
static int proc_seq_release(struct inode *inode, struct file *file)
{
struct proc_dir_entry *de = PDE(inode);
if (de->state_size)
return seq_release_private(inode, file);
return seq_release(inode, file);
}
static const struct file_operations proc_seq_fops = {
.open = proc_seq_open,
.read = seq_read,
.llseek = seq_lseek,
.release = proc_seq_release,
};
struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
struct proc_dir_entry *parent, const struct seq_operations *ops,
unsigned int state_size, void *data)
{
struct proc_dir_entry *p;
p = proc_create_reg(name, mode, &parent, data);
if (!p)
return NULL;
p->proc_fops = &proc_seq_fops;
p->seq_ops = ops;
p->state_size = state_size;
return proc_register(parent, p);
}
EXPORT_SYMBOL(proc_create_seq_private);
static int proc_single_open(struct inode *inode, struct file *file)
{
struct proc_dir_entry *de = PDE(inode);
return single_open(file, de->single_show, de->data);
}
static const struct file_operations proc_single_fops = {
.open = proc_single_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
struct proc_dir_entry *parent,
int (*show)(struct seq_file *, void *), void *data)
{
struct proc_dir_entry *p;
p = proc_create_reg(name, mode, &parent, data);
if (!p)
return NULL;
p->proc_fops = &proc_single_fops;
p->single_show = show;
return proc_register(parent, p);
}
EXPORT_SYMBOL(proc_create_single_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);
void pde_put(struct proc_dir_entry *pde)
{
if (refcount_dec_and_test(&pde->refcnt)) {
proc_free_inum(pde->low_ino);
pde_free(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 *de = NULL;
const char *fn = name;
unsigned int len;
write_lock(&proc_subdir_lock);
if (__xlate_proc_name(name, &parent, &fn) != 0) {
write_unlock(&proc_subdir_lock);
return;
}
len = strlen(fn);
de = pde_subdir_find(parent, fn, len);
if (de)
rb_erase(&de->subdir_node, &parent->subdir);
write_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(pde_subdir_first(de),
"%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
__func__, de->parent->name, de->name, pde_subdir_first(de)->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 *root = NULL, *de, *next;
const char *fn = name;
unsigned int len;
write_lock(&proc_subdir_lock);
if (__xlate_proc_name(name, &parent, &fn) != 0) {
write_unlock(&proc_subdir_lock);
return -ENOENT;
}
len = strlen(fn);
root = pde_subdir_find(parent, fn, len);
if (!root) {
write_unlock(&proc_subdir_lock);
return -ENOENT;
}
rb_erase(&root->subdir_node, &parent->subdir);
de = root;
while (1) {
next = pde_subdir_first(de);
if (next) {
rb_erase(&next->subdir_node, &de->subdir);
de = next;
continue;
}
write_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);
write_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);
/*
* Pull a user buffer into memory and pass it to the file's write handler if
* one is supplied. The ->write() method is permitted to modify the
* kernel-side buffer.
*/
ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size,
loff_t *_pos)
{
struct proc_dir_entry *pde = PDE(file_inode(f));
char *buf;
int ret;
if (!pde->write)
return -EACCES;
if (size == 0 || size > PAGE_SIZE - 1)
return -EINVAL;
buf = memdup_user_nul(ubuf, size);
if (IS_ERR(buf))
return PTR_ERR(buf);
ret = pde->write(f, buf, size);
kfree(buf);
return ret == 0 ? size : ret;
}
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