Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with
or
.
Download ZIP
tree: 8f16231b71
Fetching contributors…

Cannot retrieve contributors at this time

executable file 756 lines (601 sloc) 16.879 kb
/* Daemon interface
*
* Copyright (C) 2007 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 Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/completion.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/namei.h>
#include <linux/poll.h>
#include <linux/mount.h>
#include <linux/statfs.h>
#include <linux/ctype.h>
#include <linux/fs_struct.h>
#include "internal.h"
static int cachefiles_daemon_open(struct inode *, struct file *);
static int cachefiles_daemon_release(struct inode *, struct file *);
static ssize_t cachefiles_daemon_read(struct file *, char __user *, size_t,
loff_t *);
static ssize_t cachefiles_daemon_write(struct file *, const char __user *,
size_t, loff_t *);
static unsigned int cachefiles_daemon_poll(struct file *,
struct poll_table_struct *);
static int cachefiles_daemon_frun(struct cachefiles_cache *, char *);
static int cachefiles_daemon_fcull(struct cachefiles_cache *, char *);
static int cachefiles_daemon_fstop(struct cachefiles_cache *, char *);
static int cachefiles_daemon_brun(struct cachefiles_cache *, char *);
static int cachefiles_daemon_bcull(struct cachefiles_cache *, char *);
static int cachefiles_daemon_bstop(struct cachefiles_cache *, char *);
static int cachefiles_daemon_cull(struct cachefiles_cache *, char *);
static int cachefiles_daemon_debug(struct cachefiles_cache *, char *);
static int cachefiles_daemon_dir(struct cachefiles_cache *, char *);
static int cachefiles_daemon_inuse(struct cachefiles_cache *, char *);
static int cachefiles_daemon_secctx(struct cachefiles_cache *, char *);
static int cachefiles_daemon_tag(struct cachefiles_cache *, char *);
static unsigned long cachefiles_open;
const struct file_operations cachefiles_daemon_fops = {
.owner = THIS_MODULE,
.open = cachefiles_daemon_open,
.release = cachefiles_daemon_release,
.read = cachefiles_daemon_read,
.write = cachefiles_daemon_write,
.poll = cachefiles_daemon_poll,
};
struct cachefiles_daemon_cmd {
char name[8];
int (*handler)(struct cachefiles_cache *cache, char *args);
};
static const struct cachefiles_daemon_cmd cachefiles_daemon_cmds[] = {
{ "bind", cachefiles_daemon_bind },
{ "brun", cachefiles_daemon_brun },
{ "bcull", cachefiles_daemon_bcull },
{ "bstop", cachefiles_daemon_bstop },
{ "cull", cachefiles_daemon_cull },
{ "debug", cachefiles_daemon_debug },
{ "dir", cachefiles_daemon_dir },
{ "frun", cachefiles_daemon_frun },
{ "fcull", cachefiles_daemon_fcull },
{ "fstop", cachefiles_daemon_fstop },
{ "inuse", cachefiles_daemon_inuse },
{ "secctx", cachefiles_daemon_secctx },
{ "tag", cachefiles_daemon_tag },
{ "", NULL }
};
/*
* do various checks
*/
static int cachefiles_daemon_open(struct inode *inode, struct file *file)
{
struct cachefiles_cache *cache;
_enter("");
/* only the superuser may do this */
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/* the cachefiles device may only be open once at a time */
if (xchg(&cachefiles_open, 1) == 1)
return -EBUSY;
/* allocate a cache record */
cache = kzalloc(sizeof(struct cachefiles_cache), GFP_KERNEL);
if (!cache) {
cachefiles_open = 0;
return -ENOMEM;
}
mutex_init(&cache->daemon_mutex);
cache->active_nodes = RB_ROOT;
rwlock_init(&cache->active_lock);
init_waitqueue_head(&cache->daemon_pollwq);
/* set default caching limits
* - limit at 1% free space and/or free files
* - cull below 5% free space and/or free files
* - cease culling above 7% free space and/or free files
*/
cache->frun_percent = 7;
cache->fcull_percent = 5;
cache->fstop_percent = 1;
cache->brun_percent = 7;
cache->bcull_percent = 5;
cache->bstop_percent = 1;
file->private_data = cache;
cache->cachefilesd = file;
return 0;
}
/*
* release a cache
*/
static int cachefiles_daemon_release(struct inode *inode, struct file *file)
{
struct cachefiles_cache *cache = file->private_data;
_enter("");
ASSERT(cache);
set_bit(CACHEFILES_DEAD, &cache->flags);
cachefiles_daemon_unbind(cache);
ASSERT(!cache->active_nodes.rb_node);
/* clean up the control file interface */
cache->cachefilesd = NULL;
file->private_data = NULL;
cachefiles_open = 0;
kfree(cache);
_leave("");
return 0;
}
/*
* read the cache state
*/
static ssize_t cachefiles_daemon_read(struct file *file, char __user *_buffer,
size_t buflen, loff_t *pos)
{
struct cachefiles_cache *cache = file->private_data;
char buffer[256];
int n;
//_enter(",,%zu,", buflen);
if (!test_bit(CACHEFILES_READY, &cache->flags))
return 0;
/* check how much space the cache has */
cachefiles_has_space(cache, 0, 0);
/* summarise */
clear_bit(CACHEFILES_STATE_CHANGED, &cache->flags);
n = snprintf(buffer, sizeof(buffer),
"cull=%c"
" frun=%llx"
" fcull=%llx"
" fstop=%llx"
" brun=%llx"
" bcull=%llx"
" bstop=%llx",
test_bit(CACHEFILES_CULLING, &cache->flags) ? '1' : '0',
(unsigned long long) cache->frun,
(unsigned long long) cache->fcull,
(unsigned long long) cache->fstop,
(unsigned long long) cache->brun,
(unsigned long long) cache->bcull,
(unsigned long long) cache->bstop
);
if (n > buflen)
return -EMSGSIZE;
if (copy_to_user(_buffer, buffer, n) != 0)
return -EFAULT;
return n;
}
/*
* command the cache
*/
static ssize_t cachefiles_daemon_write(struct file *file,
const char __user *_data,
size_t datalen,
loff_t *pos)
{
const struct cachefiles_daemon_cmd *cmd;
struct cachefiles_cache *cache = file->private_data;
ssize_t ret;
char *data, *args, *cp;
//_enter(",,%zu,", datalen);
ASSERT(cache);
if (test_bit(CACHEFILES_DEAD, &cache->flags))
return -EIO;
if (datalen < 0 || datalen > PAGE_SIZE - 1)
return -EOPNOTSUPP;
/* drag the command string into the kernel so we can parse it */
data = kmalloc(datalen + 1, GFP_KERNEL);
if (!data)
return -ENOMEM;
ret = -EFAULT;
if (copy_from_user(data, _data, datalen) != 0)
goto error;
data[datalen] = '\0';
ret = -EINVAL;
if (memchr(data, '\0', datalen))
goto error;
/* strip any newline */
cp = memchr(data, '\n', datalen);
if (cp) {
if (cp == data)
goto error;
*cp = '\0';
}
/* parse the command */
ret = -EOPNOTSUPP;
for (args = data; *args; args++)
if (isspace(*args))
break;
if (*args) {
if (args == data)
goto error;
*args = '\0';
for (args++; isspace(*args); args++)
continue;
}
/* run the appropriate command handler */
for (cmd = cachefiles_daemon_cmds; cmd->name[0]; cmd++)
if (strcmp(cmd->name, data) == 0)
goto found_command;
error:
kfree(data);
//_leave(" = %zd", ret);
return ret;
found_command:
mutex_lock(&cache->daemon_mutex);
ret = -EIO;
if (!test_bit(CACHEFILES_DEAD, &cache->flags))
ret = cmd->handler(cache, args);
mutex_unlock(&cache->daemon_mutex);
if (ret == 0)
ret = datalen;
goto error;
}
/*
* poll for culling state
* - use POLLOUT to indicate culling state
*/
static unsigned int cachefiles_daemon_poll(struct file *file,
struct poll_table_struct *poll)
{
struct cachefiles_cache *cache = file->private_data;
unsigned int mask;
poll_wait(file, &cache->daemon_pollwq, poll);
mask = 0;
if (test_bit(CACHEFILES_STATE_CHANGED, &cache->flags))
mask |= POLLIN;
if (test_bit(CACHEFILES_CULLING, &cache->flags))
mask |= POLLOUT;
return mask;
}
/*
* give a range error for cache space constraints
* - can be tail-called
*/
static int cachefiles_daemon_range_error(struct cachefiles_cache *cache,
char *args)
{
kerror("Free space limits must be in range"
" 0%%<=stop<cull<run<100%%");
return -EINVAL;
}
/*
* set the percentage of files at which to stop culling
* - command: "frun <N>%"
*/
static int cachefiles_daemon_frun(struct cachefiles_cache *cache, char *args)
{
unsigned long frun;
_enter(",%s", args);
if (!*args)
return -EINVAL;
frun = simple_strtoul(args, &args, 10);
if (args[0] != '%' || args[1] != '\0')
return -EINVAL;
if (frun <= cache->fcull_percent || frun >= 100)
return cachefiles_daemon_range_error(cache, args);
cache->frun_percent = frun;
return 0;
}
/*
* set the percentage of files at which to start culling
* - command: "fcull <N>%"
*/
static int cachefiles_daemon_fcull(struct cachefiles_cache *cache, char *args)
{
unsigned long fcull;
_enter(",%s", args);
if (!*args)
return -EINVAL;
fcull = simple_strtoul(args, &args, 10);
if (args[0] != '%' || args[1] != '\0')
return -EINVAL;
if (fcull <= cache->fstop_percent || fcull >= cache->frun_percent)
return cachefiles_daemon_range_error(cache, args);
cache->fcull_percent = fcull;
return 0;
}
/*
* set the percentage of files at which to stop allocating
* - command: "fstop <N>%"
*/
static int cachefiles_daemon_fstop(struct cachefiles_cache *cache, char *args)
{
unsigned long fstop;
_enter(",%s", args);
if (!*args)
return -EINVAL;
fstop = simple_strtoul(args, &args, 10);
if (args[0] != '%' || args[1] != '\0')
return -EINVAL;
if (fstop < 0 || fstop >= cache->fcull_percent)
return cachefiles_daemon_range_error(cache, args);
cache->fstop_percent = fstop;
return 0;
}
/*
* set the percentage of blocks at which to stop culling
* - command: "brun <N>%"
*/
static int cachefiles_daemon_brun(struct cachefiles_cache *cache, char *args)
{
unsigned long brun;
_enter(",%s", args);
if (!*args)
return -EINVAL;
brun = simple_strtoul(args, &args, 10);
if (args[0] != '%' || args[1] != '\0')
return -EINVAL;
if (brun <= cache->bcull_percent || brun >= 100)
return cachefiles_daemon_range_error(cache, args);
cache->brun_percent = brun;
return 0;
}
/*
* set the percentage of blocks at which to start culling
* - command: "bcull <N>%"
*/
static int cachefiles_daemon_bcull(struct cachefiles_cache *cache, char *args)
{
unsigned long bcull;
_enter(",%s", args);
if (!*args)
return -EINVAL;
bcull = simple_strtoul(args, &args, 10);
if (args[0] != '%' || args[1] != '\0')
return -EINVAL;
if (bcull <= cache->bstop_percent || bcull >= cache->brun_percent)
return cachefiles_daemon_range_error(cache, args);
cache->bcull_percent = bcull;
return 0;
}
/*
* set the percentage of blocks at which to stop allocating
* - command: "bstop <N>%"
*/
static int cachefiles_daemon_bstop(struct cachefiles_cache *cache, char *args)
{
unsigned long bstop;
_enter(",%s", args);
if (!*args)
return -EINVAL;
bstop = simple_strtoul(args, &args, 10);
if (args[0] != '%' || args[1] != '\0')
return -EINVAL;
if (bstop < 0 || bstop >= cache->bcull_percent)
return cachefiles_daemon_range_error(cache, args);
cache->bstop_percent = bstop;
return 0;
}
/*
* set the cache directory
* - command: "dir <name>"
*/
static int cachefiles_daemon_dir(struct cachefiles_cache *cache, char *args)
{
char *dir;
_enter(",%s", args);
if (!*args) {
kerror("Empty directory specified");
return -EINVAL;
}
if (cache->rootdirname) {
kerror("Second cache directory specified");
return -EEXIST;
}
dir = kstrdup(args, GFP_KERNEL);
if (!dir)
return -ENOMEM;
cache->rootdirname = dir;
return 0;
}
/*
* set the cache security context
* - command: "secctx <ctx>"
*/
static int cachefiles_daemon_secctx(struct cachefiles_cache *cache, char *args)
{
char *secctx;
_enter(",%s", args);
if (!*args) {
kerror("Empty security context specified");
return -EINVAL;
}
if (cache->secctx) {
kerror("Second security context specified");
return -EINVAL;
}
secctx = kstrdup(args, GFP_KERNEL);
if (!secctx)
return -ENOMEM;
cache->secctx = secctx;
return 0;
}
/*
* set the cache tag
* - command: "tag <name>"
*/
static int cachefiles_daemon_tag(struct cachefiles_cache *cache, char *args)
{
char *tag;
_enter(",%s", args);
if (!*args) {
kerror("Empty tag specified");
return -EINVAL;
}
if (cache->tag)
return -EEXIST;
tag = kstrdup(args, GFP_KERNEL);
if (!tag)
return -ENOMEM;
cache->tag = tag;
return 0;
}
/*
* request a node in the cache be culled from the current working directory
* - command: "cull <name>"
*/
static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
{
struct fs_struct *fs;
struct dentry *dir;
const struct cred *saved_cred;
int ret;
_enter(",%s", args);
if (strchr(args, '/'))
goto inval;
if (!test_bit(CACHEFILES_READY, &cache->flags)) {
kerror("cull applied to unready cache");
return -EIO;
}
if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
kerror("cull applied to dead cache");
return -EIO;
}
/* extract the directory dentry from the cwd */
fs = current->fs;
read_lock(&fs->lock);
dir = dget(fs->pwd.dentry);
read_unlock(&fs->lock);
if (!S_ISDIR(dir->d_inode->i_mode))
goto notdir;
cachefiles_begin_secure(cache, &saved_cred);
ret = cachefiles_cull(cache, dir, args);
cachefiles_end_secure(cache, saved_cred);
dput(dir);
_leave(" = %d", ret);
return ret;
notdir:
dput(dir);
kerror("cull command requires dirfd to be a directory");
return -ENOTDIR;
inval:
kerror("cull command requires dirfd and filename");
return -EINVAL;
}
/*
* set debugging mode
* - command: "debug <mask>"
*/
static int cachefiles_daemon_debug(struct cachefiles_cache *cache, char *args)
{
unsigned long mask;
_enter(",%s", args);
mask = simple_strtoul(args, &args, 0);
if (args[0] != '\0')
goto inval;
cachefiles_debug = mask;
_leave(" = 0");
return 0;
inval:
kerror("debug command requires mask");
return -EINVAL;
}
/*
* find out whether an object in the current working directory is in use or not
* - command: "inuse <name>"
*/
static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
{
struct fs_struct *fs;
struct dentry *dir;
const struct cred *saved_cred;
int ret;
//_enter(",%s", args);
if (strchr(args, '/'))
goto inval;
if (!test_bit(CACHEFILES_READY, &cache->flags)) {
kerror("inuse applied to unready cache");
return -EIO;
}
if (test_bit(CACHEFILES_DEAD, &cache->flags)) {
kerror("inuse applied to dead cache");
return -EIO;
}
/* extract the directory dentry from the cwd */
fs = current->fs;
read_lock(&fs->lock);
dir = dget(fs->pwd.dentry);
read_unlock(&fs->lock);
if (!S_ISDIR(dir->d_inode->i_mode))
goto notdir;
cachefiles_begin_secure(cache, &saved_cred);
ret = cachefiles_check_in_use(cache, dir, args);
cachefiles_end_secure(cache, saved_cred);
dput(dir);
//_leave(" = %d", ret);
return ret;
notdir:
dput(dir);
kerror("inuse command requires dirfd to be a directory");
return -ENOTDIR;
inval:
kerror("inuse command requires dirfd and filename");
return -EINVAL;
}
/*
* see if we have space for a number of pages and/or a number of files in the
* cache
*/
int cachefiles_has_space(struct cachefiles_cache *cache,
unsigned fnr, unsigned bnr)
{
struct kstatfs stats;
int ret;
//_enter("{%llu,%llu,%llu,%llu,%llu,%llu},%u,%u",
// (unsigned long long) cache->frun,
// (unsigned long long) cache->fcull,
// (unsigned long long) cache->fstop,
// (unsigned long long) cache->brun,
// (unsigned long long) cache->bcull,
// (unsigned long long) cache->bstop,
// fnr, bnr);
/* find out how many pages of blockdev are available */
memset(&stats, 0, sizeof(stats));
ret = vfs_statfs(cache->mnt->mnt_root, &stats);
if (ret < 0) {
if (ret == -EIO)
cachefiles_io_error(cache, "statfs failed");
_leave(" = %d", ret);
return ret;
}
stats.f_bavail >>= cache->bshift;
//_debug("avail %llu,%llu",
// (unsigned long long) stats.f_ffree,
// (unsigned long long) stats.f_bavail);
/* see if there is sufficient space */
if (stats.f_ffree > fnr)
stats.f_ffree -= fnr;
else
stats.f_ffree = 0;
if (stats.f_bavail > bnr)
stats.f_bavail -= bnr;
else
stats.f_bavail = 0;
ret = -ENOBUFS;
if (stats.f_ffree < cache->fstop ||
stats.f_bavail < cache->bstop)
goto begin_cull;
ret = 0;
if (stats.f_ffree < cache->fcull ||
stats.f_bavail < cache->bcull)
goto begin_cull;
if (test_bit(CACHEFILES_CULLING, &cache->flags) &&
stats.f_ffree >= cache->frun &&
stats.f_bavail >= cache->brun &&
test_and_clear_bit(CACHEFILES_CULLING, &cache->flags)
) {
_debug("cease culling");
cachefiles_state_changed(cache);
}
//_leave(" = 0");
return 0;
begin_cull:
if (!test_and_set_bit(CACHEFILES_CULLING, &cache->flags)) {
_debug("### CULL CACHE ###");
cachefiles_state_changed(cache);
}
_leave(" = %d", ret);
return ret;
}
Jump to Line
Something went wrong with that request. Please try again.