linux/fs/afs/proc.c
Alexey Dobriyan 99b7623380 proc 2/2: remove struct proc_dir_entry::owner
Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy
as correctly noted at bug #12454. Someone can lookup entry with NULL
->owner, thus not pinning enything, and release it later resulting
in module refcount underflow.

We can keep ->owner and supply it at registration time like ->proc_fops
and ->data.

But this leaves ->owner as easy-manipulative field (just one C assignment)
and somebody will forget to unpin previous/pin current module when
switching ->owner. ->proc_fops is declared as "const" which should give
some thoughts.

->read_proc/->write_proc were just fixed to not require ->owner for
protection.

rmmod'ed directories will be empty and return "." and ".." -- no harm.
And directories with tricky enough readdir and lookup shouldn't be modular.
We definitely don't want such modular code.

Removing ->owner will also make PDE smaller.

So, let's nuke it.

Kudos to Jeff Layton for reminding about this, let's say, oversight.

http://bugzilla.kernel.org/show_bug.cgi?id=12454

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
2009-03-31 01:14:44 +04:00

745 lines
17 KiB
C

/* /proc interface for AFS
*
* Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/sched.h>
#include <asm/uaccess.h>
#include "internal.h"
static struct proc_dir_entry *proc_afs;
static int afs_proc_cells_open(struct inode *inode, struct file *file);
static void *afs_proc_cells_start(struct seq_file *p, loff_t *pos);
static void *afs_proc_cells_next(struct seq_file *p, void *v, loff_t *pos);
static void afs_proc_cells_stop(struct seq_file *p, void *v);
static int afs_proc_cells_show(struct seq_file *m, void *v);
static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
size_t size, loff_t *_pos);
static struct seq_operations afs_proc_cells_ops = {
.start = afs_proc_cells_start,
.next = afs_proc_cells_next,
.stop = afs_proc_cells_stop,
.show = afs_proc_cells_show,
};
static const struct file_operations afs_proc_cells_fops = {
.open = afs_proc_cells_open,
.read = seq_read,
.write = afs_proc_cells_write,
.llseek = seq_lseek,
.release = seq_release,
.owner = THIS_MODULE,
};
static int afs_proc_rootcell_open(struct inode *inode, struct file *file);
static int afs_proc_rootcell_release(struct inode *inode, struct file *file);
static ssize_t afs_proc_rootcell_read(struct file *file, char __user *buf,
size_t size, loff_t *_pos);
static ssize_t afs_proc_rootcell_write(struct file *file,
const char __user *buf,
size_t size, loff_t *_pos);
static const struct file_operations afs_proc_rootcell_fops = {
.open = afs_proc_rootcell_open,
.read = afs_proc_rootcell_read,
.write = afs_proc_rootcell_write,
.llseek = no_llseek,
.release = afs_proc_rootcell_release,
.owner = THIS_MODULE,
};
static int afs_proc_cell_volumes_open(struct inode *inode, struct file *file);
static int afs_proc_cell_volumes_release(struct inode *inode,
struct file *file);
static void *afs_proc_cell_volumes_start(struct seq_file *p, loff_t *pos);
static void *afs_proc_cell_volumes_next(struct seq_file *p, void *v,
loff_t *pos);
static void afs_proc_cell_volumes_stop(struct seq_file *p, void *v);
static int afs_proc_cell_volumes_show(struct seq_file *m, void *v);
static struct seq_operations afs_proc_cell_volumes_ops = {
.start = afs_proc_cell_volumes_start,
.next = afs_proc_cell_volumes_next,
.stop = afs_proc_cell_volumes_stop,
.show = afs_proc_cell_volumes_show,
};
static const struct file_operations afs_proc_cell_volumes_fops = {
.open = afs_proc_cell_volumes_open,
.read = seq_read,
.llseek = seq_lseek,
.release = afs_proc_cell_volumes_release,
.owner = THIS_MODULE,
};
static int afs_proc_cell_vlservers_open(struct inode *inode,
struct file *file);
static int afs_proc_cell_vlservers_release(struct inode *inode,
struct file *file);
static void *afs_proc_cell_vlservers_start(struct seq_file *p, loff_t *pos);
static void *afs_proc_cell_vlservers_next(struct seq_file *p, void *v,
loff_t *pos);
static void afs_proc_cell_vlservers_stop(struct seq_file *p, void *v);
static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v);
static struct seq_operations afs_proc_cell_vlservers_ops = {
.start = afs_proc_cell_vlservers_start,
.next = afs_proc_cell_vlservers_next,
.stop = afs_proc_cell_vlservers_stop,
.show = afs_proc_cell_vlservers_show,
};
static const struct file_operations afs_proc_cell_vlservers_fops = {
.open = afs_proc_cell_vlservers_open,
.read = seq_read,
.llseek = seq_lseek,
.release = afs_proc_cell_vlservers_release,
.owner = THIS_MODULE,
};
static int afs_proc_cell_servers_open(struct inode *inode, struct file *file);
static int afs_proc_cell_servers_release(struct inode *inode,
struct file *file);
static void *afs_proc_cell_servers_start(struct seq_file *p, loff_t *pos);
static void *afs_proc_cell_servers_next(struct seq_file *p, void *v,
loff_t *pos);
static void afs_proc_cell_servers_stop(struct seq_file *p, void *v);
static int afs_proc_cell_servers_show(struct seq_file *m, void *v);
static struct seq_operations afs_proc_cell_servers_ops = {
.start = afs_proc_cell_servers_start,
.next = afs_proc_cell_servers_next,
.stop = afs_proc_cell_servers_stop,
.show = afs_proc_cell_servers_show,
};
static const struct file_operations afs_proc_cell_servers_fops = {
.open = afs_proc_cell_servers_open,
.read = seq_read,
.llseek = seq_lseek,
.release = afs_proc_cell_servers_release,
.owner = THIS_MODULE,
};
/*
* initialise the /proc/fs/afs/ directory
*/
int afs_proc_init(void)
{
struct proc_dir_entry *p;
_enter("");
proc_afs = proc_mkdir("fs/afs", NULL);
if (!proc_afs)
goto error_dir;
p = proc_create("cells", 0, proc_afs, &afs_proc_cells_fops);
if (!p)
goto error_cells;
p = proc_create("rootcell", 0, proc_afs, &afs_proc_rootcell_fops);
if (!p)
goto error_rootcell;
_leave(" = 0");
return 0;
error_rootcell:
remove_proc_entry("cells", proc_afs);
error_cells:
remove_proc_entry("fs/afs", NULL);
error_dir:
_leave(" = -ENOMEM");
return -ENOMEM;
}
/*
* clean up the /proc/fs/afs/ directory
*/
void afs_proc_cleanup(void)
{
remove_proc_entry("rootcell", proc_afs);
remove_proc_entry("cells", proc_afs);
remove_proc_entry("fs/afs", NULL);
}
/*
* open "/proc/fs/afs/cells" which provides a summary of extant cells
*/
static int afs_proc_cells_open(struct inode *inode, struct file *file)
{
struct seq_file *m;
int ret;
ret = seq_open(file, &afs_proc_cells_ops);
if (ret < 0)
return ret;
m = file->private_data;
m->private = PDE(inode)->data;
return 0;
}
/*
* set up the iterator to start reading from the cells list and return the
* first item
*/
static void *afs_proc_cells_start(struct seq_file *m, loff_t *_pos)
{
/* lock the list against modification */
down_read(&afs_proc_cells_sem);
return seq_list_start_head(&afs_proc_cells, *_pos);
}
/*
* move to next cell in cells list
*/
static void *afs_proc_cells_next(struct seq_file *p, void *v, loff_t *pos)
{
return seq_list_next(v, &afs_proc_cells, pos);
}
/*
* clean up after reading from the cells list
*/
static void afs_proc_cells_stop(struct seq_file *p, void *v)
{
up_read(&afs_proc_cells_sem);
}
/*
* display a header line followed by a load of cell lines
*/
static int afs_proc_cells_show(struct seq_file *m, void *v)
{
struct afs_cell *cell = list_entry(v, struct afs_cell, proc_link);
if (v == &afs_proc_cells) {
/* display header on line 1 */
seq_puts(m, "USE NAME\n");
return 0;
}
/* display one cell per line on subsequent lines */
seq_printf(m, "%3d %s\n",
atomic_read(&cell->usage), cell->name);
return 0;
}
/*
* handle writes to /proc/fs/afs/cells
* - to add cells: echo "add <cellname> <IP>[:<IP>][:<IP>]"
*/
static ssize_t afs_proc_cells_write(struct file *file, const char __user *buf,
size_t size, loff_t *_pos)
{
char *kbuf, *name, *args;
int ret;
/* start by dragging the command into memory */
if (size <= 1 || size >= PAGE_SIZE)
return -EINVAL;
kbuf = kmalloc(size + 1, GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
ret = -EFAULT;
if (copy_from_user(kbuf, buf, size) != 0)
goto done;
kbuf[size] = 0;
/* trim to first NL */
name = memchr(kbuf, '\n', size);
if (name)
*name = 0;
/* split into command, name and argslist */
name = strchr(kbuf, ' ');
if (!name)
goto inval;
do {
*name++ = 0;
} while(*name == ' ');
if (!*name)
goto inval;
args = strchr(name, ' ');
if (!args)
goto inval;
do {
*args++ = 0;
} while(*args == ' ');
if (!*args)
goto inval;
/* determine command to perform */
_debug("cmd=%s name=%s args=%s", kbuf, name, args);
if (strcmp(kbuf, "add") == 0) {
struct afs_cell *cell;
cell = afs_cell_create(name, args);
if (IS_ERR(cell)) {
ret = PTR_ERR(cell);
goto done;
}
afs_put_cell(cell);
printk("kAFS: Added new cell '%s'\n", name);
} else {
goto inval;
}
ret = size;
done:
kfree(kbuf);
_leave(" = %d", ret);
return ret;
inval:
ret = -EINVAL;
printk("kAFS: Invalid Command on /proc/fs/afs/cells file\n");
goto done;
}
/*
* Stubs for /proc/fs/afs/rootcell
*/
static int afs_proc_rootcell_open(struct inode *inode, struct file *file)
{
return 0;
}
static int afs_proc_rootcell_release(struct inode *inode, struct file *file)
{
return 0;
}
static ssize_t afs_proc_rootcell_read(struct file *file, char __user *buf,
size_t size, loff_t *_pos)
{
return 0;
}
/*
* handle writes to /proc/fs/afs/rootcell
* - to initialize rootcell: echo "cell.name:192.168.231.14"
*/
static ssize_t afs_proc_rootcell_write(struct file *file,
const char __user *buf,
size_t size, loff_t *_pos)
{
char *kbuf, *s;
int ret;
/* start by dragging the command into memory */
if (size <= 1 || size >= PAGE_SIZE)
return -EINVAL;
ret = -ENOMEM;
kbuf = kmalloc(size + 1, GFP_KERNEL);
if (!kbuf)
goto nomem;
ret = -EFAULT;
if (copy_from_user(kbuf, buf, size) != 0)
goto infault;
kbuf[size] = 0;
/* trim to first NL */
s = memchr(kbuf, '\n', size);
if (s)
*s = 0;
/* determine command to perform */
_debug("rootcell=%s", kbuf);
ret = afs_cell_init(kbuf);
if (ret >= 0)
ret = size; /* consume everything, always */
infault:
kfree(kbuf);
nomem:
_leave(" = %d", ret);
return ret;
}
/*
* initialise /proc/fs/afs/<cell>/
*/
int afs_proc_cell_setup(struct afs_cell *cell)
{
struct proc_dir_entry *p;
_enter("%p{%s}", cell, cell->name);
cell->proc_dir = proc_mkdir(cell->name, proc_afs);
if (!cell->proc_dir)
goto error_dir;
p = proc_create_data("servers", 0, cell->proc_dir,
&afs_proc_cell_servers_fops, cell);
if (!p)
goto error_servers;
p = proc_create_data("vlservers", 0, cell->proc_dir,
&afs_proc_cell_vlservers_fops, cell);
if (!p)
goto error_vlservers;
p = proc_create_data("volumes", 0, cell->proc_dir,
&afs_proc_cell_volumes_fops, cell);
if (!p)
goto error_volumes;
_leave(" = 0");
return 0;
error_volumes:
remove_proc_entry("vlservers", cell->proc_dir);
error_vlservers:
remove_proc_entry("servers", cell->proc_dir);
error_servers:
remove_proc_entry(cell->name, proc_afs);
error_dir:
_leave(" = -ENOMEM");
return -ENOMEM;
}
/*
* remove /proc/fs/afs/<cell>/
*/
void afs_proc_cell_remove(struct afs_cell *cell)
{
_enter("");
remove_proc_entry("volumes", cell->proc_dir);
remove_proc_entry("vlservers", cell->proc_dir);
remove_proc_entry("servers", cell->proc_dir);
remove_proc_entry(cell->name, proc_afs);
_leave("");
}
/*
* open "/proc/fs/afs/<cell>/volumes" which provides a summary of extant cells
*/
static int afs_proc_cell_volumes_open(struct inode *inode, struct file *file)
{
struct afs_cell *cell;
struct seq_file *m;
int ret;
cell = PDE(inode)->data;
if (!cell)
return -ENOENT;
ret = seq_open(file, &afs_proc_cell_volumes_ops);
if (ret < 0)
return ret;
m = file->private_data;
m->private = cell;
return 0;
}
/*
* close the file and release the ref to the cell
*/
static int afs_proc_cell_volumes_release(struct inode *inode, struct file *file)
{
return seq_release(inode, file);
}
/*
* set up the iterator to start reading from the cells list and return the
* first item
*/
static void *afs_proc_cell_volumes_start(struct seq_file *m, loff_t *_pos)
{
struct afs_cell *cell = m->private;
_enter("cell=%p pos=%Ld", cell, *_pos);
/* lock the list against modification */
down_read(&cell->vl_sem);
return seq_list_start_head(&cell->vl_list, *_pos);
}
/*
* move to next cell in cells list
*/
static void *afs_proc_cell_volumes_next(struct seq_file *p, void *v,
loff_t *_pos)
{
struct afs_cell *cell = p->private;
_enter("cell=%p pos=%Ld", cell, *_pos);
return seq_list_next(v, &cell->vl_list, _pos);
}
/*
* clean up after reading from the cells list
*/
static void afs_proc_cell_volumes_stop(struct seq_file *p, void *v)
{
struct afs_cell *cell = p->private;
up_read(&cell->vl_sem);
}
static const char afs_vlocation_states[][4] = {
[AFS_VL_NEW] = "New",
[AFS_VL_CREATING] = "Crt",
[AFS_VL_VALID] = "Val",
[AFS_VL_NO_VOLUME] = "NoV",
[AFS_VL_UPDATING] = "Upd",
[AFS_VL_VOLUME_DELETED] = "Del",
[AFS_VL_UNCERTAIN] = "Unc",
};
/*
* display a header line followed by a load of volume lines
*/
static int afs_proc_cell_volumes_show(struct seq_file *m, void *v)
{
struct afs_cell *cell = m->private;
struct afs_vlocation *vlocation =
list_entry(v, struct afs_vlocation, link);
/* display header on line 1 */
if (v == &cell->vl_list) {
seq_puts(m, "USE STT VLID[0] VLID[1] VLID[2] NAME\n");
return 0;
}
/* display one cell per line on subsequent lines */
seq_printf(m, "%3d %s %08x %08x %08x %s\n",
atomic_read(&vlocation->usage),
afs_vlocation_states[vlocation->state],
vlocation->vldb.vid[0],
vlocation->vldb.vid[1],
vlocation->vldb.vid[2],
vlocation->vldb.name);
return 0;
}
/*
* open "/proc/fs/afs/<cell>/vlservers" which provides a list of volume
* location server
*/
static int afs_proc_cell_vlservers_open(struct inode *inode, struct file *file)
{
struct afs_cell *cell;
struct seq_file *m;
int ret;
cell = PDE(inode)->data;
if (!cell)
return -ENOENT;
ret = seq_open(file, &afs_proc_cell_vlservers_ops);
if (ret<0)
return ret;
m = file->private_data;
m->private = cell;
return 0;
}
/*
* close the file and release the ref to the cell
*/
static int afs_proc_cell_vlservers_release(struct inode *inode,
struct file *file)
{
return seq_release(inode, file);
}
/*
* set up the iterator to start reading from the cells list and return the
* first item
*/
static void *afs_proc_cell_vlservers_start(struct seq_file *m, loff_t *_pos)
{
struct afs_cell *cell = m->private;
loff_t pos = *_pos;
_enter("cell=%p pos=%Ld", cell, *_pos);
/* lock the list against modification */
down_read(&cell->vl_sem);
/* allow for the header line */
if (!pos)
return (void *) 1;
pos--;
if (pos >= cell->vl_naddrs)
return NULL;
return &cell->vl_addrs[pos];
}
/*
* move to next cell in cells list
*/
static void *afs_proc_cell_vlservers_next(struct seq_file *p, void *v,
loff_t *_pos)
{
struct afs_cell *cell = p->private;
loff_t pos;
_enter("cell=%p{nad=%u} pos=%Ld", cell, cell->vl_naddrs, *_pos);
pos = *_pos;
(*_pos)++;
if (pos >= cell->vl_naddrs)
return NULL;
return &cell->vl_addrs[pos];
}
/*
* clean up after reading from the cells list
*/
static void afs_proc_cell_vlservers_stop(struct seq_file *p, void *v)
{
struct afs_cell *cell = p->private;
up_read(&cell->vl_sem);
}
/*
* display a header line followed by a load of volume lines
*/
static int afs_proc_cell_vlservers_show(struct seq_file *m, void *v)
{
struct in_addr *addr = v;
/* display header on line 1 */
if (v == (struct in_addr *) 1) {
seq_puts(m, "ADDRESS\n");
return 0;
}
/* display one cell per line on subsequent lines */
seq_printf(m, "%pI4\n", &addr->s_addr);
return 0;
}
/*
* open "/proc/fs/afs/<cell>/servers" which provides a summary of active
* servers
*/
static int afs_proc_cell_servers_open(struct inode *inode, struct file *file)
{
struct afs_cell *cell;
struct seq_file *m;
int ret;
cell = PDE(inode)->data;
if (!cell)
return -ENOENT;
ret = seq_open(file, &afs_proc_cell_servers_ops);
if (ret < 0)
return ret;
m = file->private_data;
m->private = cell;
return 0;
}
/*
* close the file and release the ref to the cell
*/
static int afs_proc_cell_servers_release(struct inode *inode,
struct file *file)
{
return seq_release(inode, file);
}
/*
* set up the iterator to start reading from the cells list and return the
* first item
*/
static void *afs_proc_cell_servers_start(struct seq_file *m, loff_t *_pos)
__acquires(m->private->servers_lock)
{
struct afs_cell *cell = m->private;
_enter("cell=%p pos=%Ld", cell, *_pos);
/* lock the list against modification */
read_lock(&cell->servers_lock);
return seq_list_start_head(&cell->servers, *_pos);
}
/*
* move to next cell in cells list
*/
static void *afs_proc_cell_servers_next(struct seq_file *p, void *v,
loff_t *_pos)
{
struct afs_cell *cell = p->private;
_enter("cell=%p pos=%Ld", cell, *_pos);
return seq_list_next(v, &cell->servers, _pos);
}
/*
* clean up after reading from the cells list
*/
static void afs_proc_cell_servers_stop(struct seq_file *p, void *v)
__releases(p->private->servers_lock)
{
struct afs_cell *cell = p->private;
read_unlock(&cell->servers_lock);
}
/*
* display a header line followed by a load of volume lines
*/
static int afs_proc_cell_servers_show(struct seq_file *m, void *v)
{
struct afs_cell *cell = m->private;
struct afs_server *server = list_entry(v, struct afs_server, link);
char ipaddr[20];
/* display header on line 1 */
if (v == &cell->servers) {
seq_puts(m, "USE ADDR STATE\n");
return 0;
}
/* display one cell per line on subsequent lines */
sprintf(ipaddr, "%pI4", &server->addr);
seq_printf(m, "%3d %-15.15s %5d\n",
atomic_read(&server->usage), ipaddr, server->fs_state);
return 0;
}