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/* Helpers for initial module or kernel cmdline parsing
Copyright (C) 2001 Rusty Russell.

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.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/ctype.h>

/* Protects all parameters, and incidentally kmalloced_param list. */
static DEFINE_MUTEX(param_lock);

/* This just allows us to keep track of which parameters are kmalloced. */
struct kmalloced_param {
struct list_head list;
char val[];
};
static LIST_HEAD(kmalloced_params);

static void *kmalloc_parameter(unsigned int size)
{
struct kmalloced_param *p;

p = kmalloc(sizeof(*p) + size, GFP_KERNEL);
if (!p)
return NULL;

list_add(&p->list, &kmalloced_params);
return p->val;
}

/* Does nothing if parameter wasn't kmalloced above. */
static void maybe_kfree_parameter(void *param)
{
struct kmalloced_param *p;

list_for_each_entry(p, &kmalloced_params, list) {
if (p->val == param) {
list_del(&p->list);
kfree(p);
break;
}
}
}

static char dash2underscore(char c)
{
if (c == '-')
return '_';
return c;
}

bool parameqn(const char *a, const char *b, size_t n)
{
size_t i;

for (i = 0; i < n; i++) {
if (dash2underscore(a[i]) != dash2underscore(b[i]))
return false;
}
return true;
}

bool parameq(const char *a, const char *b)
{
return parameqn(a, b, strlen(a)+1);
}

static int parse_one(char *param,
char *val,
const struct kernel_param *params,
unsigned num_params,
s16 min_level,
s16 max_level,
int (*handle_unknown)(char *param, char *val))
{
unsigned int i;
int err;

/* Find parameter */
for (i = 0; i < num_params; i++) {
if (parameq(param, params[i].name)) {
if (params[i].level < min_level
|| params[i].level > max_level)
return 0;
/* No one handled NULL, so do it here. */
if (!val && params[i].ops->set != param_set_bool
&& params[i].ops->set != param_set_bint)
return -EINVAL;
pr_debug("They are equal! Calling %p\n",
params[i].ops->set);
mutex_lock(&param_lock);
err = params[i].ops->set(val, &params[i]);
mutex_unlock(&param_lock);
return err;
}
}

if (handle_unknown) {
pr_debug("Unknown argument: calling %p\n", handle_unknown);
return handle_unknown(param, val);
}

pr_debug("Unknown argument `%s'\n", param);
return -ENOENT;
}

/* You can use " around spaces, but can't escape ". */
/* Hyphens and underscores equivalent in parameter names. */
static char *next_arg(char *args, char **param, char **val)
{
unsigned int i, equals = 0;
int in_quote = 0, quoted = 0;
char *next;

if (*args == '"') {
args++;
in_quote = 1;
quoted = 1;
}

for (i = 0; args[i]; i++) {
if (isspace(args[i]) && !in_quote)
break;
if (equals == 0) {
if (args[i] == '=')
equals = i;
}
if (args[i] == '"')
in_quote = !in_quote;
}

*param = args;
if (!equals)
*val = NULL;
else {
args[equals] = '\0';
*val = args + equals + 1;

/* Don't include quotes in value. */
if (**val == '"') {
(*val)++;
if (args[i-1] == '"')
args[i-1] = '\0';
}
if (quoted && args[i-1] == '"')
args[i-1] = '\0';
}

if (args[i]) {
args[i] = '\0';
next = args + i + 1;
} else
next = args + i;

/* Chew up trailing spaces. */
return skip_spaces(next);
}

/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
int parse_args(const char *name,
char *args,
const struct kernel_param *params,
unsigned num,
s16 min_level,
s16 max_level,
int (*unknown)(char *param, char *val))
{
char *param, *val;

pr_debug("Parsing ARGS: %s\n", args);

/* Chew leading spaces */
args = skip_spaces(args);

while (*args) {
int ret;
int irq_was_disabled;

args = next_arg(args, &param, &val);
irq_was_disabled = irqs_disabled();
ret = parse_one(param, val, params, num,
min_level, max_level, unknown);
if (irq_was_disabled && !irqs_disabled()) {
printk(KERN_WARNING "parse_args(): option '%s' enabled "
"irq's!\n", param);
}
switch (ret) {
case -ENOENT:
printk(KERN_ERR "%s: Unknown parameter `%s'\n",
name, param);
return ret;
case -ENOSPC:
printk(KERN_ERR
"%s: `%s' too large for parameter `%s'\n",
name, val ?: "", param);
return ret;
case 0:
break;
default:
printk(KERN_ERR
"%s: `%s' invalid for parameter `%s'\n",
name, val ?: "", param);
return ret;
}
}

/* All parsed OK. */
return 0;
}

/* Lazy bastard, eh? */
#define STANDARD_PARAM_DEF(name, type, format, tmptype, strtolfn) \
int param_set_##name(const char *val, const struct kernel_param *kp) \
{ \
tmptype l; \
int ret; \
\
ret = strtolfn(val, 0, &l); \
if (ret < 0 || ((type)l != l)) \
return ret < 0 ? ret : -EINVAL; \
*((type *)kp->arg) = l; \
return 0; \
} \
int param_get_##name(char *buffer, const struct kernel_param *kp) \
{ \
return sprintf(buffer, format, *((type *)kp->arg)); \
} \
struct kernel_param_ops param_ops_##name = { \
.set = param_set_##name, \
.get = param_get_##name, \
}; \
EXPORT_SYMBOL(param_set_##name); \
EXPORT_SYMBOL(param_get_##name); \
EXPORT_SYMBOL(param_ops_##name)


STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, strict_strtoul);
STANDARD_PARAM_DEF(short, short, "%hi", long, strict_strtol);
STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, strict_strtoul);
STANDARD_PARAM_DEF(int, int, "%i", long, strict_strtol);
STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, strict_strtoul);
STANDARD_PARAM_DEF(long, long, "%li", long, strict_strtol);
STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul);

int param_set_charp(const char *val, const struct kernel_param *kp)
{
if (strlen(val) > 1024) {
printk(KERN_ERR "%s: string parameter too long\n",
kp->name);
return -ENOSPC;
}

maybe_kfree_parameter(*(char **)kp->arg);

/* This is a hack. We can't kmalloc in early boot, and we
* don't need to; this mangled commandline is preserved. */
if (slab_is_available()) {
*(char **)kp->arg = kmalloc_parameter(strlen(val)+1);
if (!*(char **)kp->arg)
return -ENOMEM;
strcpy(*(char **)kp->arg, val);
} else
*(const char **)kp->arg = val;

return 0;
}
EXPORT_SYMBOL(param_set_charp);

int param_get_charp(char *buffer, const struct kernel_param *kp)
{
return sprintf(buffer, "%s", *((char **)kp->arg));
}
EXPORT_SYMBOL(param_get_charp);

static void param_free_charp(void *arg)
{
maybe_kfree_parameter(*((char **)arg));
}

struct kernel_param_ops param_ops_charp = {
.set = param_set_charp,
.get = param_get_charp,
.free = param_free_charp,
};
EXPORT_SYMBOL(param_ops_charp);

/* Actually could be a bool or an int, for historical reasons. */
int param_set_bool(const char *val, const struct kernel_param *kp)
{
/* No equals means "set"... */
if (!val) val = "1";

/* One of =[yYnN01] */
return strtobool(val, kp->arg);
}
EXPORT_SYMBOL(param_set_bool);

int param_get_bool(char *buffer, const struct kernel_param *kp)
{
/* Y and N chosen as being relatively non-coder friendly */
return sprintf(buffer, "%c", *(bool *)kp->arg ? 'Y' : 'N');
}
EXPORT_SYMBOL(param_get_bool);

struct kernel_param_ops param_ops_bool = {
.set = param_set_bool,
.get = param_get_bool,
};
EXPORT_SYMBOL(param_ops_bool);

/* This one must be bool. */
int param_set_invbool(const char *val, const struct kernel_param *kp)
{
int ret;
bool boolval;
struct kernel_param dummy;

dummy.arg = &boolval;
ret = param_set_bool(val, &dummy);
if (ret == 0)
*(bool *)kp->arg = !boolval;
return ret;
}
EXPORT_SYMBOL(param_set_invbool);

int param_get_invbool(char *buffer, const struct kernel_param *kp)
{
return sprintf(buffer, "%c", (*(bool *)kp->arg) ? 'N' : 'Y');
}
EXPORT_SYMBOL(param_get_invbool);

struct kernel_param_ops param_ops_invbool = {
.set = param_set_invbool,
.get = param_get_invbool,
};
EXPORT_SYMBOL(param_ops_invbool);

int param_set_bint(const char *val, const struct kernel_param *kp)
{
struct kernel_param boolkp;
bool v;
int ret;

/* Match bool exactly, by re-using it. */
boolkp = *kp;
boolkp.arg = &v;

ret = param_set_bool(val, &boolkp);
if (ret == 0)
*(int *)kp->arg = v;
return ret;
}
EXPORT_SYMBOL(param_set_bint);

struct kernel_param_ops param_ops_bint = {
.set = param_set_bint,
.get = param_get_int,
};
EXPORT_SYMBOL(param_ops_bint);

/* We break the rule and mangle the string. */
static int param_array(const char *name,
const char *val,
unsigned int min, unsigned int max,
void *elem, int elemsize,
int (*set)(const char *, const struct kernel_param *kp),
s16 level,
unsigned int *num)
{
int ret;
struct kernel_param kp;
char save;

/* Get the name right for errors. */
kp.name = name;
kp.arg = elem;
kp.level = level;

*num = 0;
/* We expect a comma-separated list of values. */
do {
int len;

if (*num == max) {
printk(KERN_ERR "%s: can only take %i arguments\n",
name, max);
return -EINVAL;
}
len = strcspn(val, ",");

/* nul-terminate and parse */
save = val[len];
((char *)val)[len] = '\0';
BUG_ON(!mutex_is_locked(&param_lock));
ret = set(val, &kp);

if (ret != 0)
return ret;
kp.arg += elemsize;
val += len+1;
(*num)++;
} while (save == ',');

if (*num < min) {
printk(KERN_ERR "%s: needs at least %i arguments\n",
name, min);
return -EINVAL;
}
return 0;
}

static int param_array_set(const char *val, const struct kernel_param *kp)
{
const struct kparam_array *arr = kp->arr;
unsigned int temp_num;

return param_array(kp->name, val, 1, arr->max, arr->elem,
arr->elemsize, arr->ops->set, kp->level,
arr->num ?: &temp_num);
}

static int param_array_get(char *buffer, const struct kernel_param *kp)
{
int i, off, ret;
const struct kparam_array *arr = kp->arr;
struct kernel_param p;

p = *kp;
for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
if (i)
buffer[off++] = ',';
p.arg = arr->elem + arr->elemsize * i;
BUG_ON(!mutex_is_locked(&param_lock));
ret = arr->ops->get(buffer + off, &p);
if (ret < 0)
return ret;
off += ret;
}
buffer[off] = '\0';
return off;
}

static void param_array_free(void *arg)
{
unsigned int i;
const struct kparam_array *arr = arg;

if (arr->ops->free)
for (i = 0; i < (arr->num ? *arr->num : arr->max); i++)
arr->ops->free(arr->elem + arr->elemsize * i);
}

struct kernel_param_ops param_array_ops = {
.set = param_array_set,
.get = param_array_get,
.free = param_array_free,
};
EXPORT_SYMBOL(param_array_ops);

int param_set_copystring(const char *val, const struct kernel_param *kp)
{
const struct kparam_string *kps = kp->str;

if (strlen(val)+1 > kps->maxlen) {
printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",
kp->name, kps->maxlen-1);
return -ENOSPC;
}
strcpy(kps->string, val);
return 0;
}
EXPORT_SYMBOL(param_set_copystring);

int param_get_string(char *buffer, const struct kernel_param *kp)
{
const struct kparam_string *kps = kp->str;
return strlcpy(buffer, kps->string, kps->maxlen);
}
EXPORT_SYMBOL(param_get_string);

struct kernel_param_ops param_ops_string = {
.set = param_set_copystring,
.get = param_get_string,
};
EXPORT_SYMBOL(param_ops_string);

/* sysfs output in /sys/modules/XYZ/parameters/ */
#define to_module_attr(n) container_of(n, struct module_attribute, attr)
#define to_module_kobject(n) container_of(n, struct module_kobject, kobj)

extern struct kernel_param __start___param[], __stop___param[];

struct param_attribute
{
struct module_attribute mattr;
const struct kernel_param *param;
};

struct module_param_attrs
{
unsigned int num;
struct attribute_group grp;
struct param_attribute attrs[0];
};

#ifdef CONFIG_SYSFS
#define to_param_attr(n) container_of(n, struct param_attribute, mattr)

static ssize_t param_attr_show(struct module_attribute *mattr,
struct module_kobject *mk, char *buf)
{
int count;
struct param_attribute *attribute = to_param_attr(mattr);

if (!attribute->param->ops->get)
return -EPERM;

mutex_lock(&param_lock);
count = attribute->param->ops->get(buf, attribute->param);
mutex_unlock(&param_lock);
if (count > 0) {
strcat(buf, "\n");
++count;
}
return count;
}

/* sysfs always hands a nul-terminated string in buf. We rely on that. */
static ssize_t param_attr_store(struct module_attribute *mattr,
struct module_kobject *km,
const char *buf, size_t len)
{
  int err;
struct param_attribute *attribute = to_param_attr(mattr);

if (!attribute->param->ops->set)
return -EPERM;

mutex_lock(&param_lock);
err = attribute->param->ops->set(buf, attribute->param);
mutex_unlock(&param_lock);
if (!err)
return len;
return err;
}
#endif

#ifdef CONFIG_MODULES
#define __modinit
#else
#define __modinit __init
#endif

#ifdef CONFIG_SYSFS
void __kernel_param_lock(void)
{
mutex_lock(&param_lock);
}
EXPORT_SYMBOL(__kernel_param_lock);

void __kernel_param_unlock(void)
{
mutex_unlock(&param_lock);
}
EXPORT_SYMBOL(__kernel_param_unlock);

/*
* add_sysfs_param - add a parameter to sysfs
* @mk: struct module_kobject
* @kparam: the actual parameter definition to add to sysfs
* @name: name of parameter
*
* Create a kobject if for a (per-module) parameter if mp NULL, and
* create file in sysfs. Returns an error on out of memory. Always cleans up
* if there's an error.
*/
static __modinit int add_sysfs_param(struct module_kobject *mk,
const struct kernel_param *kp,
const char *name)
{
struct module_param_attrs *new;
struct attribute **attrs;
int err, num;

/* We don't bother calling this with invisible parameters. */
BUG_ON(!kp->perm);

if (!mk->mp) {
num = 0;
attrs = NULL;
} else {
num = mk->mp->num;
attrs = mk->mp->grp.attrs;
}

/* Enlarge. */
new = krealloc(mk->mp,
sizeof(*mk->mp) + sizeof(mk->mp->attrs[0]) * (num+1),
GFP_KERNEL);
if (!new) {
kfree(mk->mp);
err = -ENOMEM;
goto fail;
}
attrs = krealloc(attrs, sizeof(new->grp.attrs[0])*(num+2), GFP_KERNEL);
if (!attrs) {
err = -ENOMEM;
goto fail_free_new;
}

/* Sysfs wants everything zeroed. */
memset(new, 0, sizeof(*new));
memset(&new->attrs[num], 0, sizeof(new->attrs[num]));
memset(&attrs[num], 0, sizeof(attrs[num]));
new->grp.name = "parameters";
new->grp.attrs = attrs;

/* Tack new one on the end. */
sysfs_attr_init(&new->attrs[num].mattr.attr);
new->attrs[num].param = kp;
new->attrs[num].mattr.show = param_attr_show;
new->attrs[num].mattr.store = param_attr_store;
new->attrs[num].mattr.attr.name = (char *)name;
new->attrs[num].mattr.attr.mode = kp->perm;
new->num = num+1;

/* Fix up all the pointers, since krealloc can move us */
for (num = 0; num < new->num; num++)
new->grp.attrs[num] = &new->attrs[num].mattr.attr;
new->grp.attrs[num] = NULL;

mk->mp = new;
return 0;

fail_free_new:
kfree(new);
fail:
mk->mp = NULL;
return err;
}

#ifdef CONFIG_MODULES
static void free_module_param_attrs(struct module_kobject *mk)
{
kfree(mk->mp->grp.attrs);
kfree(mk->mp);
mk->mp = NULL;
}

/*
* module_param_sysfs_setup - setup sysfs support for one module
* @mod: module
* @kparam: module parameters (array)
* @num_params: number of module parameters
*
* Adds sysfs entries for module parameters under
* /sys/module/[mod->name]/parameters/
*/
int module_param_sysfs_setup(struct module *mod,
const struct kernel_param *kparam,
unsigned int num_params)
{
int i, err;
bool params = false;

for (i = 0; i < num_params; i++) {
if (kparam[i].perm == 0)
continue;
err = add_sysfs_param(&mod->mkobj, &kparam[i], kparam[i].name);
if (err)
return err;
params = true;
}

if (!params)
return 0;

/* Create the param group. */
err = sysfs_create_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
if (err)
free_module_param_attrs(&mod->mkobj);
return err;
}

/*
* module_param_sysfs_remove - remove sysfs support for one module
* @mod: module
*
* Remove sysfs entries for module parameters and the corresponding
* kobject.
*/
void module_param_sysfs_remove(struct module *mod)
{
if (mod->mkobj.mp) {
sysfs_remove_group(&mod->mkobj.kobj, &mod->mkobj.mp->grp);
/* We are positive that no one is using any param
* attrs at this point. Deallocate immediately. */
free_module_param_attrs(&mod->mkobj);
}
}
#endif

void destroy_params(const struct kernel_param *params, unsigned num)
{
unsigned int i;

for (i = 0; i < num; i++)
if (params[i].ops->free)
params[i].ops->free(params[i].arg);
}

static struct module_kobject * __init locate_module_kobject(const char *name)
{
struct module_kobject *mk;
struct kobject *kobj;
int err;

kobj = kset_find_obj(module_kset, name);
if (kobj) {
mk = to_module_kobject(kobj);
} else {
mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
BUG_ON(!mk);

mk->mod = THIS_MODULE;
mk->kobj.kset = module_kset;
err = kobject_init_and_add(&mk->kobj, &module_ktype, NULL,
"%s", name);
#ifdef CONFIG_MODULES
if (!err)
err = sysfs_create_file(&mk->kobj, &module_uevent.attr);
#endif
if (err) {
kobject_put(&mk->kobj);
printk(KERN_ERR
"Module '%s' failed add to sysfs, error number %d\n",
name, err);
printk(KERN_ERR
"The system will be unstable now.\n");
return NULL;
}

/* So that we hold reference in both cases. */
kobject_get(&mk->kobj);
}

return mk;
}

static void __init kernel_add_sysfs_param(const char *name,
struct kernel_param *kparam,
unsigned int name_skip)
{
struct module_kobject *mk;
int err;

mk = locate_module_kobject(name);
if (!mk)
return;

/* We need to remove old parameters before adding more. */
if (mk->mp)
sysfs_remove_group(&mk->kobj, &mk->mp->grp);

/* These should not fail at boot. */
err = add_sysfs_param(mk, kparam, kparam->name + name_skip);
BUG_ON(err);
err = sysfs_create_group(&mk->kobj, &mk->mp->grp);
BUG_ON(err);
kobject_uevent(&mk->kobj, KOBJ_ADD);
kobject_put(&mk->kobj);
}

/*
* param_sysfs_builtin - add contents in /sys/parameters for built-in modules
*
* Add module_parameters to sysfs for "modules" built into the kernel.
*
* The "module" name (KBUILD_MODNAME) is stored before a dot, the
* "parameter" name is stored behind a dot in kernel_param->name. So,
* extract the "module" name for all built-in kernel_param-eters,
* and for all who have the same, call kernel_add_sysfs_param.
*/
static void __init param_sysfs_builtin(void)
{
struct kernel_param *kp;
unsigned int name_len;
char modname[MODULE_NAME_LEN];

for (kp = __start___param; kp < __stop___param; kp++) {
char *dot;

if (kp->perm == 0)
continue;

dot = strchr(kp->name, '.');
if (!dot) {
/* This happens for core_param() */
strcpy(modname, "kernel");
name_len = 0;
} else {
name_len = dot - kp->name + 1;
strlcpy(modname, kp->name, name_len);
}
kernel_add_sysfs_param(modname, kp, name_len);
}
}

ssize_t __modver_version_show(struct module_attribute *mattr,
struct module_kobject *mk, char *buf)
{
struct module_version_attribute *vattr =
container_of(mattr, struct module_version_attribute, mattr);

return sprintf(buf, "%s\n", vattr->version);
}

extern const struct module_version_attribute *__start___modver[];
extern const struct module_version_attribute *__stop___modver[];

static void __init version_sysfs_builtin(void)
{
const struct module_version_attribute **p;
struct module_kobject *mk;
int err;

for (p = __start___modver; p < __stop___modver; p++) {
const struct module_version_attribute *vattr = *p;

mk = locate_module_kobject(vattr->module_name);
if (mk) {
err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
kobject_uevent(&mk->kobj, KOBJ_ADD);
kobject_put(&mk->kobj);
}
}
}

/* module-related sysfs stuff */

static ssize_t module_attr_show(struct kobject *kobj,
struct attribute *attr,
char *buf)
{
struct module_attribute *attribute;
struct module_kobject *mk;
int ret;

attribute = to_module_attr(attr);
mk = to_module_kobject(kobj);

if (!attribute->show)
return -EIO;

ret = attribute->show(attribute, mk, buf);

return ret;
}

static ssize_t module_attr_store(struct kobject *kobj,
struct attribute *attr,
const char *buf, size_t len)
{
struct module_attribute *attribute;
struct module_kobject *mk;
int ret;

attribute = to_module_attr(attr);
mk = to_module_kobject(kobj);

if (!attribute->store)
return -EIO;

ret = attribute->store(attribute, mk, buf, len);

return ret;
}

static const struct sysfs_ops module_sysfs_ops = {
.show = module_attr_show,
.store = module_attr_store,
};

static int uevent_filter(struct kset *kset, struct kobject *kobj)
{
struct kobj_type *ktype = get_ktype(kobj);

if (ktype == &module_ktype)
return 1;
return 0;
}

static const struct kset_uevent_ops module_uevent_ops = {
.filter = uevent_filter,
};

struct kset *module_kset;
int module_sysfs_initialized;

struct kobj_type module_ktype = {
.sysfs_ops = &module_sysfs_ops,
};

/*
* param_sysfs_init - wrapper for built-in params support
*/
static int __init param_sysfs_init(void)
{
module_kset = kset_create_and_add("module", &module_uevent_ops, NULL);
if (!module_kset) {
printk(KERN_WARNING "%s (%d): error creating kset\n",
__FILE__, __LINE__);
return -ENOMEM;
}
module_sysfs_initialized = 1;

version_sysfs_builtin();
param_sysfs_builtin();

return 0;
}
subsys_initcall(param_sysfs_init);

#endif /* CONFIG_SYSFS */
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