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linux/kernel/params.c

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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/moduleparam.h>
#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>
#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt, a...)
#endif
static inline char dash2underscore(char c)
{
if (c == '-')
return '_';
return c;
}
static inline int parameq(const char *input, const char *paramname)
{
unsigned int i;
for (i = 0; dash2underscore(input[i]) == paramname[i]; i++)
if (input[i] == '\0')
return 1;
return 0;
}
static int parse_one(char *param,
char *val,
struct kernel_param *params,
unsigned num_params,
int (*handle_unknown)(char *param, char *val))
{
unsigned int i;
/* Find parameter */
for (i = 0; i < num_params; i++) {
if (parameq(param, params[i].name)) {
DEBUGP("They are equal! Calling %p\n",
params[i].set);
return params[i].set(val, &params[i]);
}
}
if (handle_unknown) {
DEBUGP("Unknown argument: calling %p\n", handle_unknown);
return handle_unknown(param, val);
}
DEBUGP("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 (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. */
while (*next == ' ')
next++;
return next;
}
/* Args looks like "foo=bar,bar2 baz=fuz wiz". */
int parse_args(const char *name,
char *args,
struct kernel_param *params,
unsigned num,
int (*unknown)(char *param, char *val))
{
char *param, *val;
DEBUGP("Parsing ARGS: %s\n", args);
/* Chew leading spaces */
while (*args == ' ')
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, 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, struct kernel_param *kp) \
{ \
char *endp; \
tmptype l; \
\
if (!val) return -EINVAL; \
l = strtolfn(val, &endp, 0); \
if (endp == val || ((type)l != l)) \
return -EINVAL; \
*((type *)kp->arg) = l; \
return 0; \
} \
int param_get_##name(char *buffer, struct kernel_param *kp) \
{ \
return sprintf(buffer, format, *((type *)kp->arg)); \
}
STANDARD_PARAM_DEF(byte, unsigned char, "%c", unsigned long, simple_strtoul);
STANDARD_PARAM_DEF(short, short, "%hi", long, simple_strtol);
STANDARD_PARAM_DEF(ushort, unsigned short, "%hu", unsigned long, simple_strtoul);
STANDARD_PARAM_DEF(int, int, "%i", long, simple_strtol);
STANDARD_PARAM_DEF(uint, unsigned int, "%u", unsigned long, simple_strtoul);
STANDARD_PARAM_DEF(long, long, "%li", long, simple_strtol);
STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, simple_strtoul);
int param_set_charp(const char *val, struct kernel_param *kp)
{
if (!val) {
printk(KERN_ERR "%s: string parameter expected\n",
kp->name);
return -EINVAL;
}
if (strlen(val) > 1024) {
printk(KERN_ERR "%s: string parameter too long\n",
kp->name);
return -ENOSPC;
}
*(char **)kp->arg = (char *)val;
return 0;
}
int param_get_charp(char *buffer, struct kernel_param *kp)
{
return sprintf(buffer, "%s", *((char **)kp->arg));
}
int param_set_bool(const char *val, struct kernel_param *kp)
{
/* No equals means "set"... */
if (!val) val = "1";
/* One of =[yYnN01] */
switch (val[0]) {
case 'y': case 'Y': case '1':
*(int *)kp->arg = 1;
return 0;
case 'n': case 'N': case '0':
*(int *)kp->arg = 0;
return 0;
}
return -EINVAL;
}
int param_get_bool(char *buffer, struct kernel_param *kp)
{
/* Y and N chosen as being relatively non-coder friendly */
return sprintf(buffer, "%c", (*(int *)kp->arg) ? 'Y' : 'N');
}
int param_set_invbool(const char *val, struct kernel_param *kp)
{
int boolval, ret;
struct kernel_param dummy;
dummy.arg = &boolval;
ret = param_set_bool(val, &dummy);
if (ret == 0)
*(int *)kp->arg = !boolval;
return ret;
}
int param_get_invbool(char *buffer, struct kernel_param *kp)
{
return sprintf(buffer, "%c", (*(int *)kp->arg) ? 'N' : 'Y');
}
/* 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 *, struct kernel_param *kp),
unsigned int *num)
{
int ret;
struct kernel_param kp;
char save;
/* Get the name right for errors. */
kp.name = name;
kp.arg = elem;
/* No equals sign? */
if (!val) {
printk(KERN_ERR "%s: expects arguments\n", name);
return -EINVAL;
}
*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';
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;
}
int param_array_set(const char *val, 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->set, arr->num ?: &temp_num);
}
int param_array_get(char *buffer, 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;
ret = arr->get(buffer + off, &p);
if (ret < 0)
return ret;
off += ret;
}
buffer[off] = '\0';
return off;
}
int param_set_copystring(const char *val, struct kernel_param *kp)
{
const struct kparam_string *kps = kp->str;
if (!val) {
printk(KERN_ERR "%s: missing param set value\n", kp->name);
return -EINVAL;
}
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;
}
int param_get_string(char *buffer, struct kernel_param *kp)
{
const struct kparam_string *kps = kp->str;
return strlcpy(buffer, kps->string, kps->maxlen);
}
/* sysfs output in /sys/modules/XYZ/parameters/ */
extern struct kernel_param __start___param[], __stop___param[];
struct param_attribute
{
struct module_attribute mattr;
struct kernel_param *param;
};
struct module_param_attrs
{
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 *mod, char *buf)
{
int count;
struct param_attribute *attribute = to_param_attr(mattr);
if (!attribute->param->get)
return -EPERM;
count = attribute->param->get(buf, attribute->param);
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 *owner,
const char *buf, size_t len)
{
int err;
struct param_attribute *attribute = to_param_attr(mattr);
if (!attribute->param->set)
return -EPERM;
err = attribute->param->set(buf, attribute->param);
if (!err)
return len;
return err;
}
#endif
#ifdef CONFIG_MODULES
#define __modinit
#else
#define __modinit __init
#endif
#ifdef CONFIG_SYSFS
/*
* param_sysfs_setup - setup sysfs support for one module or KBUILD_MODNAME
* @mk: struct module_kobject (contains parent kobject)
* @kparam: array of struct kernel_param, the actual parameter definitions
* @num_params: number of entries in array
* @name_skip: offset where the parameter name start in kparam[].name. Needed for built-in "modules"
*
* Create a kobject for a (per-module) group of parameters, and create files
* in sysfs. A pointer to the param_kobject is returned on success,
* NULL if there's no parameter to export, or other ERR_PTR(err).
*/
static __modinit struct module_param_attrs *
param_sysfs_setup(struct module_kobject *mk,
struct kernel_param *kparam,
unsigned int num_params,
unsigned int name_skip)
{
struct module_param_attrs *mp;
unsigned int valid_attrs = 0;
unsigned int i, size[2];
struct param_attribute *pattr;
struct attribute **gattr;
int err;
for (i=0; i<num_params; i++) {
if (kparam[i].perm)
valid_attrs++;
}
if (!valid_attrs)
return NULL;
size[0] = ALIGN(sizeof(*mp) +
valid_attrs * sizeof(mp->attrs[0]),
sizeof(mp->grp.attrs[0]));
size[1] = (valid_attrs + 1) * sizeof(mp->grp.attrs[0]);
mp = kzalloc(size[0] + size[1], GFP_KERNEL);
if (!mp)
return ERR_PTR(-ENOMEM);
mp->grp.name = "parameters";
mp->grp.attrs = (void *)mp + size[0];
pattr = &mp->attrs[0];
gattr = &mp->grp.attrs[0];
for (i = 0; i < num_params; i++) {
struct kernel_param *kp = &kparam[i];
if (kp->perm) {
pattr->param = kp;
pattr->mattr.show = param_attr_show;
pattr->mattr.store = param_attr_store;
pattr->mattr.attr.name = (char *)&kp->name[name_skip];
pattr->mattr.attr.mode = kp->perm;
*(gattr++) = &(pattr++)->mattr.attr;
}
}
*gattr = NULL;
if ((err = sysfs_create_group(&mk->kobj, &mp->grp))) {
kfree(mp);
return ERR_PTR(err);
}
return mp;
}
#ifdef CONFIG_MODULES
/*
* 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, and creates a link from
* /sys/module/[mod->name]/parameters to /sys/parameters/[mod->name]/
*/
int module_param_sysfs_setup(struct module *mod,
struct kernel_param *kparam,
unsigned int num_params)
{
struct module_param_attrs *mp;
mp = param_sysfs_setup(&mod->mkobj, kparam, num_params, 0);
if (IS_ERR(mp))
return PTR_ERR(mp);
mod->param_attrs = mp;
return 0;
}
/*
* 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->param_attrs) {
sysfs_remove_group(&mod->mkobj.kobj,
&mod->param_attrs->grp);
/* We are positive that no one is using any param
* attrs at this point. Deallocate immediately. */
kfree(mod->param_attrs);
mod->param_attrs = NULL;
}
}
#endif
/*
* kernel_param_sysfs_setup - wrapper for built-in params support
*/
static void __init kernel_param_sysfs_setup(const char *name,
struct kernel_param *kparam,
unsigned int num_params,
unsigned int name_skip)
{
struct module_kobject *mk;
int ret;
mk = kzalloc(sizeof(struct module_kobject), GFP_KERNEL);
BUG_ON(!mk);
mk->mod = THIS_MODULE;
mk->kobj.kset = module_kset;
ret = kobject_init_and_add(&mk->kobj, &module_ktype, NULL, "%s", name);
if (ret) {
kobject_put(&mk->kobj);
printk(KERN_ERR "Module '%s' failed to be added to sysfs, "
"error number %d\n", name, ret);
printk(KERN_ERR "The system will be unstable now.\n");
return;
}
param_sysfs_setup(mk, kparam, num_params, name_skip);
kobject_uevent(&mk->kobj, KOBJ_ADD);
}
/*
* 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_param_sysfs_setup.
*/
static void __init param_sysfs_builtin(void)
{
struct kernel_param *kp, *kp_begin = NULL;
unsigned int i, name_len, count = 0;
char modname[MODULE_NAME_LEN + 1] = "";
for (i=0; i < __stop___param - __start___param; i++) {
char *dot;
size_t max_name_len;
kp = &__start___param[i];
max_name_len =
min_t(size_t, MODULE_NAME_LEN, strlen(kp->name));
dot = memchr(kp->name, '.', max_name_len);
if (!dot) {
DEBUGP("couldn't find period in first %d characters "
"of %s\n", MODULE_NAME_LEN, kp->name);
continue;
}
name_len = dot - kp->name;
/* new kbuild_modname? */
if (strlen(modname) != name_len
|| strncmp(modname, kp->name, name_len) != 0) {
/* add a new kobject for previous kernel_params. */
if (count)
kernel_param_sysfs_setup(modname,
kp_begin,
count,
strlen(modname)+1);
strncpy(modname, kp->name, name_len);
modname[name_len] = '\0';
count = 0;
kp_begin = kp;
}
count++;
}
/* last kernel_params need to be registered as well */
if (count)
kernel_param_sysfs_setup(modname, kp_begin, count,
strlen(modname)+1);
}
/* module-related sysfs stuff */
#define to_module_attr(n) container_of(n, struct module_attribute, attr);
#define to_module_kobject(n) container_of(n, struct module_kobject, kobj);
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->mod, 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->mod, buf, len);
return ret;
}
static 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 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;
param_sysfs_builtin();
return 0;
}
subsys_initcall(param_sysfs_init);
#endif /* CONFIG_SYSFS */
EXPORT_SYMBOL(param_set_byte);
EXPORT_SYMBOL(param_get_byte);
EXPORT_SYMBOL(param_set_short);
EXPORT_SYMBOL(param_get_short);
EXPORT_SYMBOL(param_set_ushort);
EXPORT_SYMBOL(param_get_ushort);
EXPORT_SYMBOL(param_set_int);
EXPORT_SYMBOL(param_get_int);
EXPORT_SYMBOL(param_set_uint);
EXPORT_SYMBOL(param_get_uint);
EXPORT_SYMBOL(param_set_long);
EXPORT_SYMBOL(param_get_long);
EXPORT_SYMBOL(param_set_ulong);
EXPORT_SYMBOL(param_get_ulong);
EXPORT_SYMBOL(param_set_charp);
EXPORT_SYMBOL(param_get_charp);
EXPORT_SYMBOL(param_set_bool);
EXPORT_SYMBOL(param_get_bool);
EXPORT_SYMBOL(param_set_invbool);
EXPORT_SYMBOL(param_get_invbool);
EXPORT_SYMBOL(param_array_set);
EXPORT_SYMBOL(param_array_get);
EXPORT_SYMBOL(param_set_copystring);
EXPORT_SYMBOL(param_get_string);
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