linux/kernel/params.c at master · fabgithub/linux · GitHub

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/* Helpers for initial module or kernel cmdline parsing

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 char *doing,

const struct kernel_param *params,

unsigned num_params,

s16 min_level,

s16 max_level,

int (*handle_unknown)(char *param, char *val,

const char *doing))

{

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("handling %s with %p\n", param,

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("doing %s: %s='%s'\n", doing, param, val);

return handle_unknown(param, val, doing);

}

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 *doing,

char *args,

const struct kernel_param *params,

unsigned num,

s16 min_level,

s16 max_level,

int (*unknown)(char *param, char *val, const char *doing))

{

char *param, *val;

/* Chew leading spaces */

args = skip_spaces(args);

if (*args)

pr_debug("doing %s, parsing ARGS: '%s'\n", doing, 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, doing, params, num,

min_level, max_level, unknown);

if (irq_was_disabled && !irqs_disabled())

pr_warn("%s: option '%s' enabled irq's!\n",

doing, param);

switch (ret) {

case -ENOENT:

pr_err("%s: Unknown parameter `%s'\n", doing, param);

return ret;

case -ENOSPC:

pr_err("%s: `%s' too large for parameter `%s'\n",

doing, val ?: "", param);

return ret;

case 0:

break;

default:

pr_err("%s: `%s' invalid for parameter `%s'\n",

doing, 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) {

pr_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) {

pr_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) {

pr_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) {

pr_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(attrs);

err = -ENOMEM;

goto fail;

}

/* Despite looking like the typical realloc() bug, this is safe.

* We *want* the old 'attrs' to be freed either way, and we'll store

* the new one in the success case. */

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);

pr_crit("Adding module '%s' to sysfs failed (%d), the system may be unstable.\n",

name, err);

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 sysfs 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 */

linux/kernel/params.c at master · fabgithub/linux · GitHub

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