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linux/kernel/params.c
Peter Oberparleiter 26d052bfce param: allow whitespace as kernel parameter separator 
Some boot mechanisms require that kernel parameters are stored in a
separate file which is loaded to memory without further processing
(e.g. the "Load from FTP" method on s390). When such a file contains
newline characters, the kernel parameter preceding the newline might
not be correctly parsed (due to the newline being stuck to the end of
the actual parameter value) which can lead to boot failures.

This patch improves kernel command line usability in such a situation
by allowing generic whitespace characters as separators between kernel
parameters.

Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-09-25 00:32:58 +09:30

803 lines
18 KiB
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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>
#include <linux/ctype.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 (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. */
while (isspace(*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 (isspace(*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) \
{ \
tmptype l; \
int ret; \
\
if (!val) return -EINVAL; \
ret = strtolfn(val, 0, &l); \
if (ret == -EINVAL || ((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, 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, 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;
}
if (kp->flags & KPARAM_KMALLOCED)
kfree(*(char **)kp->arg);
/* This is a hack. We can't need to strdup in early boot, and we
* don't need to; this mangled commandline is preserved. */
if (slab_is_available()) {
kp->flags |= KPARAM_KMALLOCED;
*(char **)kp->arg = kstrdup(val, GFP_KERNEL);
if (!kp->arg)
return -ENOMEM;
} else
*(const char **)kp->arg = val;
return 0;
}
int param_get_charp(char *buffer, struct kernel_param *kp)
{
return sprintf(buffer, "%s", *((char **)kp->arg));
}
/* Actually could be a bool or an int, for historical reasons. */
int param_set_bool(const char *val, struct kernel_param *kp)
{
bool v;
/* No equals means "set"... */
if (!val) val = "1";
/* One of =[yYnN01] */
switch (val[0]) {
case 'y': case 'Y': case '1':
v = true;
break;
case 'n': case 'N': case '0':
v = false;
break;
default:
return -EINVAL;
}
if (kp->flags & KPARAM_ISBOOL)
*(bool *)kp->arg = v;
else
*(int *)kp->arg = v;
return 0;
}
int param_get_bool(char *buffer, struct kernel_param *kp)
{
bool val;
if (kp->flags & KPARAM_ISBOOL)
val = *(bool *)kp->arg;
else
val = *(int *)kp->arg;
/* Y and N chosen as being relatively non-coder friendly */
return sprintf(buffer, "%c", val ? 'Y' : 'N');
}
/* This one must be bool. */
int param_set_invbool(const char *val, struct kernel_param *kp)
{
int ret;
bool boolval;
struct kernel_param dummy;
dummy.arg = &boolval;
dummy.flags = KPARAM_ISBOOL;
ret = param_set_bool(val, &dummy);
if (ret == 0)
*(bool *)kp->arg = !boolval;
return ret;
}
int param_get_invbool(char *buffer, struct kernel_param *kp)
{
return sprintf(buffer, "%c", (*(bool *)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/ */
#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;
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 *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
/*
* 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,
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. */
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,
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].flags & KPARAM_KMALLOCED)
kfree(*(char **)params[i].arg);
}
static void __init kernel_add_sysfs_param(const char *name,
struct kernel_param *kparam,
unsigned int name_skip)
{
struct module_kobject *mk;
struct kobject *kobj;
int err;
kobj = kset_find_obj(module_kset, name);
if (kobj) {
/* We already have one. Remove params so we can add more. */
mk = to_module_kobject(kobj);
/* We need to remove it before adding parameters. */
sysfs_remove_group(&mk->kobj, &mk->mp->grp);
} 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);
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;
}
/* So that exit path is even. */
kobject_get(&mk->kobj);
}
/* 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);
}
}
/* 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->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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