Viewing file:  generic.c (12.63 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*
* 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 <asm/uaccess.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#define __NO_VERSION__
#include <linux/module.h>
#include <asm/bitops.h>
static ssize_t proc_file_read(struct file * file, char * buf,
size_t nbytes, loff_t *ppos);
static ssize_t proc_file_write(struct file * file, const char * buffer,
size_t count, loff_t *ppos);
static loff_t proc_file_lseek(struct file *, loff_t, int);
int proc_match(int len, const char *name,struct proc_dir_entry * de)
{
if (!de || !de->low_ino)
return 0;
if (de->namelen != len)
return 0;
return !memcmp(name, de->name, len);
}
static struct file_operations proc_file_operations = {
llseek: proc_file_lseek,
read: proc_file_read,
write: proc_file_write,
};
#ifndef MIN
#define MIN(a,b) (((a) < (b)) ? (a) : (b))
#endif
/* buffer size is one page but our output routines use some slack for overruns */
#define PROC_BLOCK_SIZE (PAGE_SIZE - 1024)
static ssize_t
proc_file_read(struct file * file, char * buf, size_t nbytes, loff_t *ppos)
{
struct inode * inode = file->f_dentry->d_inode;
char *page;
ssize_t retval=0;
int eof=0;
ssize_t n, count;
char *start;
struct proc_dir_entry * dp;
dp = (struct proc_dir_entry *) inode->u.generic_ip;
if (!(page = (char*) __get_free_page(GFP_KERNEL)))
return -ENOMEM;
while ((nbytes > 0) && !eof)
{
count = MIN(PROC_BLOCK_SIZE, nbytes);
start = NULL;
if (dp->get_info) {
/*
* Handle backwards compatibility with the old net
* routines.
*/
n = dp->get_info(page, &start, *ppos, count);
if (n < count)
eof = 1;
} else if (dp->read_proc) {
n = dp->read_proc(page, &start, *ppos,
count, &eof, dp->data);
} else
break;
if (!start) {
/*
* For proc files that are less than 4k
*/
start = page + *ppos;
n -= *ppos;
if (n <= 0)
break;
if (n > count)
n = count;
}
if (n == 0)
break; /* End of file */
if (n < 0) {
if (retval == 0)
retval = n;
break;
}
/* This is a hack to allow mangling of file pos independent
* of actual bytes read. Simply place the data at page,
* return the bytes, and set `start' to the desired offset
* as an unsigned int. - Paul.Russell@rustcorp.com.au
*/
n -= copy_to_user(buf, start < page ? page : start, n);
if (n == 0) {
if (retval == 0)
retval = -EFAULT;
break;
}
*ppos += start < page ? (long)start : n; /* Move down the file */
nbytes -= n;
buf += n;
retval += n;
}
free_page((unsigned long) page);
return retval;
}
static ssize_t
proc_file_write(struct file * file, const char * buffer,
size_t count, loff_t *ppos)
{
struct inode *inode = file->f_dentry->d_inode;
struct proc_dir_entry * dp;
dp = (struct proc_dir_entry *) inode->u.generic_ip;
if (!dp->write_proc)
return -EIO;
/* FIXME: does this routine need ppos? probably... */
return dp->write_proc(file, buffer, count, dp->data);
}
static loff_t
proc_file_lseek(struct file * file, loff_t offset, int orig)
{
switch (orig) {
case 0:
if (offset < 0)
return -EINVAL;
file->f_pos = offset;
return(file->f_pos);
case 1:
if (offset + file->f_pos < 0)
return -EINVAL;
file->f_pos += offset;
return(file->f_pos);
case 2:
return(-EINVAL);
default:
return(-EINVAL);
}
}
/*
* 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;
int len;
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)
return -ENOENT;
cp += len + 1;
}
*residual = cp;
*ret = de;
return 0;
}
static unsigned long proc_alloc_map[(PROC_NDYNAMIC + BITS_PER_LONG - 1) / BITS_PER_LONG];
spinlock_t proc_alloc_map_lock = SPIN_LOCK_UNLOCKED;
static int make_inode_number(void)
{
int i;
spin_lock(&proc_alloc_map_lock);
i = find_first_zero_bit(proc_alloc_map, PROC_NDYNAMIC);
if (i < 0 || i >= PROC_NDYNAMIC) {
i = -1;
goto out;
}
set_bit(i, proc_alloc_map);
i += PROC_DYNAMIC_FIRST;
out:
spin_unlock(&proc_alloc_map_lock);
return i;
}
static int proc_readlink(struct dentry *dentry, char *buffer, int buflen)
{
char *s=((struct proc_dir_entry *)dentry->d_inode->u.generic_ip)->data;
return vfs_readlink(dentry, buffer, buflen, s);
}
static int proc_follow_link(struct dentry *dentry, struct nameidata *nd)
{
char *s=((struct proc_dir_entry *)dentry->d_inode->u.generic_ip)->data;
return vfs_follow_link(nd, s);
}
static struct inode_operations proc_link_inode_operations = {
readlink: proc_readlink,
follow_link: proc_follow_link,
};
/*
* As some entries in /proc are volatile, we want to
* get rid of unused dentries. This could be made
* smarter: we could keep a "volatile" flag in the
* inode to indicate which ones to keep.
*/
static int proc_delete_dentry(struct dentry * dentry)
{
return 1;
}
static struct dentry_operations proc_dentry_operations =
{
d_delete: proc_delete_dentry,
};
/*
* Don't create negative dentries here, return -ENOENT by hand
* instead.
*/
struct dentry *proc_lookup(struct inode * dir, struct dentry *dentry)
{
struct inode *inode;
struct proc_dir_entry * de;
int error;
error = -ENOENT;
inode = NULL;
de = (struct proc_dir_entry *) dir->u.generic_ip;
if (de) {
for (de = de->subdir; de ; de = de->next) {
if (!de || !de->low_ino)
continue;
if (de->namelen != dentry->d_name.len)
continue;
if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
int ino = de->low_ino;
error = -EINVAL;
inode = proc_get_inode(dir->i_sb, ino, de);
break;
}
}
}
if (inode) {
dentry->d_op = &proc_dentry_operations;
d_add(dentry, inode);
return NULL;
}
return ERR_PTR(error);
}
/*
* 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(struct file * filp,
void * dirent, filldir_t filldir)
{
struct proc_dir_entry * de;
unsigned int ino;
int i;
struct inode *inode = filp->f_dentry->d_inode;
ino = inode->i_ino;
de = (struct proc_dir_entry *) inode->u.generic_ip;
if (!de)
return -EINVAL;
i = filp->f_pos;
switch (i) {
case 0:
if (filldir(dirent, ".", 1, i, ino, DT_DIR) < 0)
return 0;
i++;
filp->f_pos++;
/* fall through */
case 1:
if (filldir(dirent, "..", 2, i,
filp->f_dentry->d_parent->d_inode->i_ino,
DT_DIR) < 0)
return 0;
i++;
filp->f_pos++;
/* fall through */
default:
de = de->subdir;
i -= 2;
for (;;) {
if (!de)
return 1;
if (!i)
break;
de = de->next;
i--;
}
do {
if (filldir(dirent, de->name, de->namelen, filp->f_pos,
de->low_ino, de->mode >> 12) < 0)
return 0;
filp->f_pos++;
de = de->next;
} while (de);
}
return 1;
}
/*
* These are the generic /proc directory operations. They
* use the in-memory "struct proc_dir_entry" tree to parse
* the /proc directory.
*/
static struct file_operations proc_dir_operations = {
read: generic_read_dir,
readdir: proc_readdir,
};
/*
* proc directories can do almost nothing..
*/
static struct inode_operations proc_dir_inode_operations = {
lookup: proc_lookup,
};
static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
{
int i;
i = make_inode_number();
if (i < 0)
return -EAGAIN;
dp->low_ino = i;
dp->next = dir->subdir;
dp->parent = dir;
dir->subdir = dp;
if (S_ISDIR(dp->mode)) {
if (dp->proc_iops == NULL) {
dp->proc_fops = &proc_dir_operations;
dp->proc_iops = &proc_dir_inode_operations;
}
dir->nlink++;
} else if (S_ISLNK(dp->mode)) {
if (dp->proc_iops == NULL)
dp->proc_iops = &proc_link_inode_operations;
} else if (S_ISREG(dp->mode)) {
if (dp->proc_fops == NULL)
dp->proc_fops = &proc_file_operations;
}
return 0;
}
/*
* Kill an inode that got unregistered..
*/
static void proc_kill_inodes(struct proc_dir_entry *de)
{
struct list_head *p;
struct super_block *sb = proc_super;
if (!sb) return;
/*
* Actually it's a partial revoke().
*/
file_list_lock();
for (p = sb->s_files.next; p != &sb->s_files; p = p->next) {
struct file * filp = list_entry(p, struct file, f_list);
struct dentry * dentry = filp->f_dentry;
struct inode * inode;
struct file_operations *fops;
if (dentry->d_op != &proc_dentry_operations)
continue;
inode = dentry->d_inode;
if (inode->u.generic_ip != de)
continue;
fops = filp->f_op;
filp->f_op = NULL;
fops_put(fops);
}
file_list_unlock();
}
static struct proc_dir_entry *proc_create(struct proc_dir_entry **parent,
const char *name,
mode_t mode,
nlink_t nlink)
{
struct proc_dir_entry *ent = NULL;
const char *fn = name;
int len;
/* make sure name is valid */
if (!name || !strlen(name)) goto out;
if (!(*parent) && xlate_proc_name(name, parent, &fn) != 0)
goto out;
len = strlen(fn);
ent = kmalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
if (!ent) goto out;
memset(ent, 0, sizeof(struct proc_dir_entry));
memcpy(((char *) ent) + sizeof(struct proc_dir_entry), fn, len + 1);
ent->name = ((char *) ent) + sizeof(*ent);
ent->namelen = len;
ent->mode = mode;
ent->nlink = nlink;
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);
proc_register(parent, ent);
} else {
kfree(ent);
ent = NULL;
}
}
return ent;
}
struct proc_dir_entry *proc_mknod(const char *name, mode_t mode,
struct proc_dir_entry *parent, kdev_t rdev)
{
struct proc_dir_entry *ent;
ent = proc_create(&parent,name,mode,1);
if (ent) {
ent->rdev = rdev;
proc_register(parent, ent);
}
return ent;
}
struct proc_dir_entry *proc_mkdir_mode(const char *name, mode_t mode,
struct proc_dir_entry *parent)
{
struct proc_dir_entry *ent;
ent = proc_create(&parent, name, S_IFDIR | mode, 2);
if (ent) {
ent->proc_fops = &proc_dir_operations;
ent->proc_iops = &proc_dir_inode_operations;
proc_register(parent, ent);
}
return ent;
}
struct proc_dir_entry *proc_mkdir(const char *name,
struct proc_dir_entry *parent)
{
return proc_mkdir_mode(name, S_IRUGO | S_IXUGO, parent);
}
struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
struct proc_dir_entry *parent)
{
struct proc_dir_entry *ent;
nlink_t nlink;
if (S_ISDIR(mode)) {
if ((mode & S_IALLUGO) == 0)
mode |= S_IRUGO | S_IXUGO;
nlink = 2;
} else {
if ((mode & S_IFMT) == 0)
mode |= S_IFREG;
if ((mode & S_IALLUGO) == 0)
mode |= S_IRUGO;
nlink = 1;
}
ent = proc_create(&parent,name,mode,nlink);
if (ent) {
if (S_ISDIR(mode)) {
ent->proc_fops = &proc_dir_operations;
ent->proc_iops = &proc_dir_inode_operations;
}
proc_register(parent, ent);
}
return ent;
}
void free_proc_entry(struct proc_dir_entry *de)
{
int ino = de->low_ino;
if (ino < PROC_DYNAMIC_FIRST ||
ino >= PROC_DYNAMIC_FIRST+PROC_NDYNAMIC)
return;
if (S_ISLNK(de->mode) && de->data)
kfree(de->data);
kfree(de);
}
/*
* Remove a /proc entry and free it if it's not currently in use.
* If it is in use, we set the 'deleted' flag.
*/
void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
{
struct proc_dir_entry **p;
struct proc_dir_entry *de;
const char *fn = name;
int len;
if (!parent && xlate_proc_name(name, &parent, &fn) != 0)
goto out;
len = strlen(fn);
for (p = &parent->subdir; *p; p=&(*p)->next ) {
if (!proc_match(len, fn, *p))
continue;
de = *p;
*p = de->next;
de->next = NULL;
if (S_ISDIR(de->mode))
parent->nlink--;
clear_bit(de->low_ino - PROC_DYNAMIC_FIRST,
proc_alloc_map);
proc_kill_inodes(de);
de->nlink = 0;
if (!atomic_read(&de->count))
free_proc_entry(de);
else {
de->deleted = 1;
printk("remove_proc_entry: %s/%s busy, count=%d\n",
parent->name, de->name, atomic_read(&de->count));
}
break;
}
out:
return;
}
|