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6f8880d8e6
linux/fs/afs/proc.c
David Howells 6f8880d8e6 afs: Implement @sys substitution handling 
Implement the AFS feature by which @sys at the end of a pathname component
may be substituted for one of a list of values, typically naming the
operating system.  Up to 16 alternatives may be specified and these are
tried in turn until one works.  Each network namespace has[*] a separate
independent list.

Upon creation of a new network namespace, the list of values is
initialised[*] to a single OpenAFS-compatible string representing arch type
plus "_linux26".  For example, on x86_64, the sysname is "amd64_linux26".

[*] Or will, once network namespace support is finalised in kAFS.

The list may be set by:

	# for i in foo bar linux-x86_64; do echo $i; done >/proc/fs/afs/sysname

for which separate writes to the same fd are amalgamated and applied on
close.  The LF character may be used as a separator to specify multiple
items in the same write() call.

The list may be cleared by:

	# echo >/proc/fs/afs/sysname

and read by:

	# cat /proc/fs/afs/sysname
	foo
	bar
	linux-x86_64

Signed-off-by: David Howells <dhowells@redhat.com>
2018-04-09 21:12:31 +01:00

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/* /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 <linux/uaccess.h>
#include "internal.h"
static inline struct afs_net *afs_proc2net(struct file *f)
{
return &__afs_net;
}
static inline struct afs_net *afs_seq2net(struct seq_file *m)
{
return &__afs_net; // TODO: use seq_file_net(m)
}
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 const 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,
};
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 = {
.read = afs_proc_rootcell_read,
.write = afs_proc_rootcell_write,
.llseek = no_llseek,
};
static int afs_proc_cell_volumes_open(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 const 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 = seq_release,
};
static int afs_proc_cell_vlservers_open(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 const 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 = seq_release,
};
static int afs_proc_servers_open(struct inode *inode, struct file *file);
static void *afs_proc_servers_start(struct seq_file *p, loff_t *pos);
static void *afs_proc_servers_next(struct seq_file *p, void *v,
loff_t *pos);
static void afs_proc_servers_stop(struct seq_file *p, void *v);
static int afs_proc_servers_show(struct seq_file *m, void *v);
static const struct seq_operations afs_proc_servers_ops = {
.start = afs_proc_servers_start,
.next = afs_proc_servers_next,
.stop = afs_proc_servers_stop,
.show = afs_proc_servers_show,
};
static const struct file_operations afs_proc_servers_fops = {
.open = afs_proc_servers_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static int afs_proc_sysname_open(struct inode *inode, struct file *file);
static int afs_proc_sysname_release(struct inode *inode, struct file *file);
static void *afs_proc_sysname_start(struct seq_file *p, loff_t *pos);
static void *afs_proc_sysname_next(struct seq_file *p, void *v,
loff_t *pos);
static void afs_proc_sysname_stop(struct seq_file *p, void *v);
static int afs_proc_sysname_show(struct seq_file *m, void *v);
static ssize_t afs_proc_sysname_write(struct file *file,
const char __user *buf,
size_t size, loff_t *_pos);
static const struct seq_operations afs_proc_sysname_ops = {
.start = afs_proc_sysname_start,
.next = afs_proc_sysname_next,
.stop = afs_proc_sysname_stop,
.show = afs_proc_sysname_show,
};
static const struct file_operations afs_proc_sysname_fops = {
.open = afs_proc_sysname_open,
.read = seq_read,
.llseek = seq_lseek,
.release = afs_proc_sysname_release,
.write = afs_proc_sysname_write,
};
/*
* initialise the /proc/fs/afs/ directory
*/
int afs_proc_init(struct afs_net *net)
{
_enter("");
net->proc_afs = proc_mkdir("fs/afs", NULL);
if (!net->proc_afs)
goto error_dir;
if (!proc_create("cells", 0644, net->proc_afs, &afs_proc_cells_fops) ||
!proc_create("rootcell", 0644, net->proc_afs, &afs_proc_rootcell_fops) ||
!proc_create("servers", 0644, net->proc_afs, &afs_proc_servers_fops) ||
!proc_create("sysname", 0644, net->proc_afs, &afs_proc_sysname_fops))
goto error_tree;
_leave(" = 0");
return 0;
error_tree:
proc_remove(net->proc_afs);
error_dir:
_leave(" = -ENOMEM");
return -ENOMEM;
}
/*
* clean up the /proc/fs/afs/ directory
*/
void afs_proc_cleanup(struct afs_net *net)
{
proc_remove(net->proc_afs);
net->proc_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_DATA(inode);
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)
__acquires(rcu)
{
struct afs_net *net = afs_seq2net(m);
rcu_read_lock();
return seq_list_start_head(&net->proc_cells, *_pos);
}
/*
* move to next cell in cells list
*/
static void *afs_proc_cells_next(struct seq_file *m, void *v, loff_t *pos)
{
struct afs_net *net = afs_seq2net(m);
return seq_list_next(v, &net->proc_cells, pos);
}
/*
* clean up after reading from the cells list
*/
static void afs_proc_cells_stop(struct seq_file *m, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
/*
* 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);
struct afs_net *net = afs_seq2net(m);
if (v == &net->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, "%3u %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)
{
struct afs_net *net = afs_proc2net(file);
char *kbuf, *name, *args;
int ret;
/* start by dragging the command into memory */
if (size <= 1 || size >= PAGE_SIZE)
return -EINVAL;
kbuf = memdup_user_nul(buf, size);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
/* 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_lookup_cell(net, name, strlen(name), args, true);
if (IS_ERR(cell)) {
ret = PTR_ERR(cell);
goto done;
}
if (test_and_set_bit(AFS_CELL_FL_NO_GC, &cell->flags))
afs_put_cell(net, 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;
}
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)
{
struct afs_net *net = afs_proc2net(file);
char *kbuf, *s;
int ret;
/* start by dragging the command into memory */
if (size <= 1 || size >= PAGE_SIZE)
return -EINVAL;
kbuf = memdup_user_nul(buf, size);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
ret = -EINVAL;
if (kbuf[0] == '.')
goto out;
if (memchr(kbuf, '/', size))
goto out;
/* 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(net, kbuf);
if (ret >= 0)
ret = size; /* consume everything, always */
out:
kfree(kbuf);
_leave(" = %d", ret);
return ret;
}
/*
* initialise /proc/fs/afs/<cell>/
*/
int afs_proc_cell_setup(struct afs_net *net, struct afs_cell *cell)
{
struct proc_dir_entry *dir;
_enter("%p{%s},%p", cell, cell->name, net->proc_afs);
dir = proc_mkdir(cell->name, net->proc_afs);
if (!dir)
goto error_dir;
if (!proc_create_data("vlservers", 0, dir,
&afs_proc_cell_vlservers_fops, cell) ||
!proc_create_data("volumes", 0, dir,
&afs_proc_cell_volumes_fops, cell))
goto error_tree;
_leave(" = 0");
return 0;
error_tree:
remove_proc_subtree(cell->name, net->proc_afs);
error_dir:
_leave(" = -ENOMEM");
return -ENOMEM;
}
/*
* remove /proc/fs/afs/<cell>/
*/
void afs_proc_cell_remove(struct afs_net *net, struct afs_cell *cell)
{
_enter("");
remove_proc_subtree(cell->name, net->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_DATA(inode);
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;
}
/*
* 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)
__acquires(cell->proc_lock)
{
struct afs_cell *cell = m->private;
_enter("cell=%p pos=%Ld", cell, *_pos);
read_lock(&cell->proc_lock);
return seq_list_start_head(&cell->proc_volumes, *_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->proc_volumes, _pos);
}
/*
* clean up after reading from the cells list
*/
static void afs_proc_cell_volumes_stop(struct seq_file *p, void *v)
__releases(cell->proc_lock)
{
struct afs_cell *cell = p->private;
read_unlock(&cell->proc_lock);
}
static const char afs_vol_types[3][3] = {
[AFSVL_RWVOL] = "RW",
[AFSVL_ROVOL] = "RO",
[AFSVL_BACKVOL] = "BK",
};
/*
* 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_volume *vol = list_entry(v, struct afs_volume, proc_link);
/* Display header on line 1 */
if (v == &cell->proc_volumes) {
seq_puts(m, "USE VID TY\n");
return 0;
}
seq_printf(m, "%3d %08x %s\n",
atomic_read(&vol->usage), vol->vid,
afs_vol_types[vol->type]);
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_DATA(inode);
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;
}
/*
* 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)
__acquires(rcu)
{
struct afs_addr_list *alist;
struct afs_cell *cell = m->private;
loff_t pos = *_pos;
rcu_read_lock();
alist = rcu_dereference(cell->vl_addrs);
/* allow for the header line */
if (!pos)
return (void *) 1;
pos--;
if (!alist || pos >= alist->nr_addrs)
return NULL;
return alist->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_addr_list *alist;
struct afs_cell *cell = p->private;
loff_t pos;
alist = rcu_dereference(cell->vl_addrs);
pos = *_pos;
(*_pos)++;
if (!alist || pos >= alist->nr_addrs)
return NULL;
return alist->addrs + pos;
}
/*
* clean up after reading from the cells list
*/
static void afs_proc_cell_vlservers_stop(struct seq_file *p, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
/*
* 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 sockaddr_rxrpc *addr = v;
/* display header on line 1 */
if (v == (void *)1) {
seq_puts(m, "ADDRESS\n");
return 0;
}
/* display one cell per line on subsequent lines */
seq_printf(m, "%pISp\n", &addr->transport);
return 0;
}
/*
* open "/proc/fs/afs/servers" which provides a summary of active
* servers
*/
static int afs_proc_servers_open(struct inode *inode, struct file *file)
{
return seq_open(file, &afs_proc_servers_ops);
}
/*
* Set up the iterator to start reading from the server list and return the
* first item.
*/
static void *afs_proc_servers_start(struct seq_file *m, loff_t *_pos)
__acquires(rcu)
{
struct afs_net *net = afs_seq2net(m);
rcu_read_lock();
return seq_hlist_start_head_rcu(&net->fs_proc, *_pos);
}
/*
* move to next cell in cells list
*/
static void *afs_proc_servers_next(struct seq_file *m, void *v, loff_t *_pos)
{
struct afs_net *net = afs_seq2net(m);
return seq_hlist_next_rcu(v, &net->fs_proc, _pos);
}
/*
* clean up after reading from the cells list
*/
static void afs_proc_servers_stop(struct seq_file *p, void *v)
__releases(rcu)
{
rcu_read_unlock();
}
/*
* display a header line followed by a load of volume lines
*/
static int afs_proc_servers_show(struct seq_file *m, void *v)
{
struct afs_server *server;
struct afs_addr_list *alist;
if (v == SEQ_START_TOKEN) {
seq_puts(m, "UUID USE ADDR\n");
return 0;
}
server = list_entry(v, struct afs_server, proc_link);
alist = rcu_dereference(server->addresses);
seq_printf(m, "%pU %3d %pISp\n",
&server->uuid,
atomic_read(&server->usage),
&alist->addrs[alist->index].transport);
return 0;
}
void afs_put_sysnames(struct afs_sysnames *sysnames)
{
int i;
if (sysnames && refcount_dec_and_test(&sysnames->usage)) {
for (i = 0; i < sysnames->nr; i++)
if (sysnames->subs[i] != afs_init_sysname &&
sysnames->subs[i] != sysnames->blank)
kfree(sysnames->subs[i]);
}
}
/*
* Handle opening of /proc/fs/afs/sysname. If it is opened for writing, we
* assume the caller wants to change the substitution list and we allocate a
* buffer to hold the list.
*/
static int afs_proc_sysname_open(struct inode *inode, struct file *file)
{
struct afs_sysnames *sysnames;
struct seq_file *m;
int ret;
ret = seq_open(file, &afs_proc_sysname_ops);
if (ret < 0)
return ret;
if (file->f_mode & FMODE_WRITE) {
sysnames = kzalloc(sizeof(*sysnames), GFP_KERNEL);
if (!sysnames) {
seq_release(inode, file);
return -ENOMEM;
}
refcount_set(&sysnames->usage, 1);
m = file->private_data;
m->private = sysnames;
}
return 0;
}
/*
* Handle writes to /proc/fs/afs/sysname to set the @sys substitution.
*/
static ssize_t afs_proc_sysname_write(struct file *file,
const char __user *buf,
size_t size, loff_t *_pos)
{
struct afs_sysnames *sysnames;
struct seq_file *m = file->private_data;
char *kbuf = NULL, *s, *p, *sub;
int ret, len;
sysnames = m->private;
if (!sysnames)
return -EINVAL;
if (sysnames->error)
return sysnames->error;
if (size >= PAGE_SIZE - 1) {
sysnames->error = -EINVAL;
return -EINVAL;
}
if (size == 0)
return 0;
kbuf = memdup_user_nul(buf, size);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
inode_lock(file_inode(file));
p = kbuf;
while ((s = strsep(&p, " \t\n"))) {
len = strlen(s);
if (len == 0)
continue;
ret = -ENAMETOOLONG;
if (len >= AFSNAMEMAX)
goto error;
if (len >= 4 &&
s[len - 4] == '@' &&
s[len - 3] == 's' &&
s[len - 2] == 'y' &&
s[len - 1] == 's')
/* Protect against recursion */
goto invalid;
if (s[0] == '.' &&
(len < 2 || (len == 2 && s[1] == '.')))
goto invalid;
if (memchr(s, '/', len))
goto invalid;
ret = -EFBIG;
if (sysnames->nr >= AFS_NR_SYSNAME)
goto out;
if (strcmp(s, afs_init_sysname) == 0) {
sub = (char *)afs_init_sysname;
} else {
ret = -ENOMEM;
sub = kmemdup(s, len + 1, GFP_KERNEL);
if (!sub)
goto out;
}
sysnames->subs[sysnames->nr] = sub;
sysnames->nr++;
}
ret = size; /* consume everything, always */
out:
inode_unlock(file_inode(file));
kfree(kbuf);
return ret;
invalid:
ret = -EINVAL;
error:
sysnames->error = ret;
goto out;
}
static int afs_proc_sysname_release(struct inode *inode, struct file *file)
{
struct afs_sysnames *sysnames, *kill = NULL;
struct seq_file *m = file->private_data;
struct afs_net *net = afs_seq2net(m);
sysnames = m->private;
if (sysnames) {
if (!sysnames->error) {
kill = sysnames;
if (sysnames->nr == 0) {
sysnames->subs[0] = sysnames->blank;
sysnames->nr++;
}
write_lock(&net->sysnames_lock);
kill = net->sysnames;
net->sysnames = sysnames;
write_unlock(&net->sysnames_lock);
}
afs_put_sysnames(kill);
}
return seq_release(inode, file);
}
static void *afs_proc_sysname_start(struct seq_file *m, loff_t *pos)
__acquires(&net->sysnames_lock)
{
struct afs_net *net = afs_seq2net(m);
struct afs_sysnames *names = net->sysnames;
read_lock(&net->sysnames_lock);
if (*pos >= names->nr)
return NULL;
return (void *)(unsigned long)(*pos + 1);
}
static void *afs_proc_sysname_next(struct seq_file *m, void *v, loff_t *pos)
{
struct afs_net *net = afs_seq2net(m);
struct afs_sysnames *names = net->sysnames;
*pos += 1;
if (*pos >= names->nr)
return NULL;
return (void *)(unsigned long)(*pos + 1);
}
static void afs_proc_sysname_stop(struct seq_file *m, void *v)
__releases(&net->sysnames_lock)
{
struct afs_net *net = afs_seq2net(m);
read_unlock(&net->sysnames_lock);
}
static int afs_proc_sysname_show(struct seq_file *m, void *v)
{
struct afs_net *net = afs_seq2net(m);
struct afs_sysnames *sysnames = net->sysnames;
unsigned int i = (unsigned long)v - 1;
if (i < sysnames->nr)
seq_printf(m, "%s\n", sysnames->subs[i]);
return 0;
}
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