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/*
* linux/fs/proc/inode.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/file.h>
#include <linux/locks.h>
#include <linux/limits.h>
#include <linux/config.h>
#include <asm/system.h>
#include <asm/uaccess.h>
extern void free_proc_entry(struct proc_dir_entry *);
struct proc_dir_entry * de_get(struct proc_dir_entry *de)
{
if (de)
de->count++;
return de;
}
/*
* Decrements the use count and checks for deferred deletion.
*/
void de_put(struct proc_dir_entry *de)
{
if (de) {
if (!de->count) {
printk("de_put: entry %s already free!\n", de->name);
return;
}
if (!--de->count) {
if (de->deleted) {
printk("de_put: deferred delete of %s\n",
de->name);
free_proc_entry(de);
}
}
}
}
static void proc_put_inode(struct inode *inode)
{
#ifdef CONFIG_SUN_OPENPROMFS_MODULE
if ((inode->i_ino >= PROC_OPENPROM_FIRST) &&
(inode->i_ino < PROC_OPENPROM_FIRST + PROC_NOPENPROM) &&
proc_openprom_use)
(*proc_openprom_use)(inode, 0);
#endif
/*
* Kill off unused inodes ... VFS will unhash and
* delete the inode if we set i_nlink to zero.
*/
if (inode->i_count == 1)
inode->i_nlink = 0;
}
/*
* Decrement the use count of the proc_dir_entry.
*/
static void proc_delete_inode(struct inode *inode)
{
struct proc_dir_entry *de = inode->u.generic_ip;
#if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE)
if ((inode->i_ino >= PROC_OPENPROM_FIRST) &&
(inode->i_ino < PROC_OPENPROM_FIRST + PROC_NOPENPROM))
return;
#endif
if (de) {
/*
* Call the fill_inode hook to release module counts.
*/
if (de->fill_inode)
de->fill_inode(inode, 0);
de_put(de);
}
}
static struct super_operations proc_sops = {
proc_read_inode,
proc_write_inode,
proc_put_inode,
proc_delete_inode, /* delete_inode(struct inode *) */
NULL,
NULL,
NULL,
proc_statfs,
NULL
};
static int parse_options(char *options,uid_t *uid,gid_t *gid)
{
char *this_char,*value;
*uid = current->uid;
*gid = current->gid;
if (!options) return 1;
for (this_char = strtok(options,","); this_char; this_char = strtok(NULL,",")) {
if ((value = strchr(this_char,'=')) != NULL)
*value++ = 0;
if (!strcmp(this_char,"uid")) {
if (!value || !*value)
return 0;
*uid = simple_strtoul(value,&value,0);
if (*value)
return 0;
}
else if (!strcmp(this_char,"gid")) {
if (!value || !*value)
return 0;
*gid = simple_strtoul(value,&value,0);
if (*value)
return 0;
}
else return 1;
}
return 1;
}
/*
* The standard rules, copied from fs/namei.c:permission().
*/
static int standard_permission(struct inode *inode, int mask)
{
int mode = inode->i_mode;
if ((mask & S_IWOTH) && IS_RDONLY(inode) &&
(S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
return -EROFS; /* Nobody gets write access to a read-only fs */
else if ((mask & S_IWOTH) && IS_IMMUTABLE(inode))
return -EACCES; /* Nobody gets write access to an immutable file */
else if (current->fsuid == inode->i_uid)
mode >>= 6;
else if (in_group_p(inode->i_gid))
mode >>= 3;
if (((mode & mask & S_IRWXO) == mask) || capable(CAP_DAC_OVERRIDE))
return 0;
/* read and search access */
if ((mask == S_IROTH) ||
(S_ISDIR(mode) && !(mask & ~(S_IROTH | S_IXOTH))))
if (capable(CAP_DAC_READ_SEARCH))
return 0;
return -EACCES;
}
/*
* Set up permission rules for processes looking at other processes.
* You're not allowed to see a process unless it has the same or more
* restricted root than your own. This prevents a chrooted processes
* from escaping through the /proc entries of less restricted
* processes, and thus allows /proc to be safely mounted in a chrooted
* area.
*
* Note that root (uid 0) doesn't get permission for this either,
* since chroot is stronger than root.
*
* XXX TODO: use the dentry mechanism to make off-limits procs simply
* invisible rather than denied? Does each namespace root get its own
* dentry tree?
*
* This also applies the default permissions checks, as it only adds
* restrictions.
*
* Jeremy Fitzhardinge <jeremy@zip.com.au>
*/
int proc_permission(struct inode *inode, int mask)
{
struct task_struct *p;
unsigned long ino = inode->i_ino;
unsigned long pid;
struct dentry *de, *base;
if (standard_permission(inode, mask) != 0)
return -EACCES;
/*
* Find the root of the processes being examined (if any).
* XXX Surely there's a better way of doing this?
*/
if (ino >= PROC_OPENPROM_FIRST &&
ino < PROC_OPENPROM_FIRST + PROC_NOPENPROM)
return 0; /* already allowed */
pid = ino >> 16;
if (pid == 0)
return 0; /* already allowed */
de = NULL;
base = current->fs->root;
read_lock(&tasklist_lock);
p = find_task_by_pid(pid);
if (p && p->fs)
de = p->fs->root;
read_unlock(&tasklist_lock); /* FIXME! */
if (p == NULL)
return -EACCES; /* ENOENT? */
if (de == NULL)
{
/* kswapd and bdflush don't have proper root or cwd... */
return -EACCES;
}
/* XXX locking? */
for(;;)
{
struct dentry *parent;
if (de == base)
return 0; /* already allowed */
de = de->d_covers;
parent = de->d_parent;
if (de == parent)
break;
de = parent;
}
return -EACCES; /* incompatible roots */
}
struct inode * proc_get_inode(struct super_block * sb, int ino,
struct proc_dir_entry * de)
{
struct inode * inode;
/*
* Increment the use count so the dir entry can't disappear.
*/
de_get(de);
#if 1
/* shouldn't ever happen */
if (de && de->deleted)
printk("proc_iget: using deleted entry %s, count=%d\n", de->name, de->count);
#endif
inode = iget(sb, ino);
if (!inode)
goto out_fail;
#ifdef CONFIG_SUN_OPENPROMFS_MODULE
if ((inode->i_ino >= PROC_OPENPROM_FIRST)
&& (inode->i_ino < PROC_OPENPROM_FIRST + PROC_NOPENPROM)
&& proc_openprom_use)
(*proc_openprom_use)(inode, 1);
#endif
/* N.B. How can this test ever fail?? */
if (inode->i_sb != sb)
printk("proc_get_inode: inode fubar\n");
inode->u.generic_ip = (void *) de;
if (de) {
if (de->mode) {
inode->i_mode = de->mode;
inode->i_uid = de->uid;
inode->i_gid = de->gid;
}
if (de->size)
inode->i_size = de->size;
if (de->ops)
inode->i_op = de->ops;
if (de->nlink)
inode->i_nlink = de->nlink;
/*
* The fill_inode routine should use this call
* to increment module counts, if necessary.
*/
if (de->fill_inode)
de->fill_inode(inode, 1);
}
/*
* Fixup the root inode's nlink value
*/
if (inode->i_ino == PROC_ROOT_INO) {
struct task_struct *p;
read_lock(&tasklist_lock);
for_each_task(p) {
if (p->pid)
inode->i_nlink++;
}
read_unlock(&tasklist_lock);
}
out:
return inode;
out_fail:
de_put(de);
goto out;
}
struct super_block *proc_read_super(struct super_block *s,void *data,
int silent)
{
struct inode * root_inode;
lock_super(s);
s->s_blocksize = 1024;
s->s_blocksize_bits = 10;
s->s_magic = PROC_SUPER_MAGIC;
s->s_op = &proc_sops;
root_inode = proc_get_inode(s, PROC_ROOT_INO, &proc_root);
if (!root_inode)
goto out_no_root;
s->s_root = d_alloc_root(root_inode, NULL);
if (!s->s_root)
goto out_no_root;
parse_options(data, &root_inode->i_uid, &root_inode->i_gid);
unlock_super(s);
return s;
out_no_root:
printk("proc_read_super: get root inode failed\n");
iput(root_inode);
s->s_dev = 0;
unlock_super(s);
return NULL;
}
int proc_statfs(struct super_block *sb, struct statfs *buf, int bufsiz)
{
struct statfs tmp;
tmp.f_type = PROC_SUPER_MAGIC;
tmp.f_bsize = PAGE_SIZE/sizeof(long);
tmp.f_blocks = 0;
tmp.f_bfree = 0;
tmp.f_bavail = 0;
tmp.f_files = 0;
tmp.f_ffree = 0;
tmp.f_namelen = NAME_MAX;
return copy_to_user(buf, &tmp, bufsiz) ? -EFAULT : 0;
}
void proc_read_inode(struct inode * inode)
{
unsigned long ino, pid;
struct task_struct * p;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
inode->i_blocks = 0;
inode->i_blksize = 1024;
ino = inode->i_ino;
if (ino >= PROC_OPENPROM_FIRST &&
ino < PROC_OPENPROM_FIRST + PROC_NOPENPROM)
goto out;
inode->i_op = NULL;
inode->i_mode = 0;
inode->i_uid = 0;
inode->i_gid = 0;
inode->i_nlink = 1;
inode->i_size = 0;
pid = ino >> 16;
if (!pid)
goto out;
read_lock(&tasklist_lock);
p = find_task_by_pid(pid);
if (!p)
goto out_unlock;
ino &= 0x0000ffff;
if (ino == PROC_PID_INO || p->dumpable) {
inode->i_uid = p->euid;
inode->i_gid = p->egid;
}
if (ino & PROC_PID_FD_DIR) {
struct file * file;
ino &= 0x7fff;
file = fcheck_task(p, ino);
if (!file)
goto out_unlock;
inode->i_op = &proc_link_inode_operations;
inode->i_size = 64;
inode->i_mode = S_IFLNK;
if (file->f_mode & 1)
inode->i_mode |= S_IRUSR | S_IXUSR;
if (file->f_mode & 2)
inode->i_mode |= S_IWUSR | S_IXUSR;
}
out_unlock:
/* Defer unlocking until we're done with the task */
read_unlock(&tasklist_lock);
out:
return;
}
void proc_write_inode(struct inode * inode)
{
}
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