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linux-next/include/linux/moduleparam.h
Rusty Russell 51e158c12a param: hand arguments after -- straight to init 
The kernel passes any args it doesn't need through to init, except it
assumes anything containing '.' belongs to the kernel (for a module).
This change means all users can clearly distinguish which arguments
are for init.

For example, the kernel uses debug ("dee-bug") to mean log everything to
the console, where systemd uses the debug from the Scandinavian "day-boog"
meaning "fail to boot".  If a future versions uses argv[] instead of
reading /proc/cmdline, this confusion will be avoided.

eg: test 'FOO="this is --foo"' -- 'systemd.debug="true true true"'

Gives:
argv[0] = '/debug-init'
argv[1] = 'test'
argv[2] = 'systemd.debug=true true true'
envp[0] = 'HOME=/'
envp[1] = 'TERM=linux'
envp[2] = 'FOO=this is --foo'

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-28 11:48:34 +09:30

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#ifndef _LINUX_MODULE_PARAMS_H
#define _LINUX_MODULE_PARAMS_H
/* (C) Copyright 2001, 2002 Rusty Russell IBM Corporation */
#include <linux/init.h>
#include <linux/stringify.h>
#include <linux/kernel.h>
/* You can override this manually, but generally this should match the
module name. */
#ifdef MODULE
#define MODULE_PARAM_PREFIX /* empty */
#else
#define MODULE_PARAM_PREFIX KBUILD_MODNAME "."
#endif
/* Chosen so that structs with an unsigned long line up. */
#define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
#ifdef MODULE
#define __MODULE_INFO(tag, name, info) \
static const char __UNIQUE_ID(name)[] \
__used __attribute__((section(".modinfo"), unused, aligned(1))) \
= __stringify(tag) "=" info
#else /* !MODULE */
/* This struct is here for syntactic coherency, it is not used */
#define __MODULE_INFO(tag, name, info) \
struct __UNIQUE_ID(name) {}
#endif
#define __MODULE_PARM_TYPE(name, _type) \
__MODULE_INFO(parmtype, name##type, #name ":" _type)
/* One for each parameter, describing how to use it. Some files do
multiple of these per line, so can't just use MODULE_INFO. */
#define MODULE_PARM_DESC(_parm, desc) \
__MODULE_INFO(parm, _parm, #_parm ":" desc)
struct kernel_param;
/*
* Flags available for kernel_param_ops
*
* NOARG - the parameter allows for no argument (foo instead of foo=1)
*/
enum {
KERNEL_PARAM_FL_NOARG = (1 << 0)
};
struct kernel_param_ops {
/* How the ops should behave */
unsigned int flags;
/* Returns 0, or -errno. arg is in kp->arg. */
int (*set)(const char *val, const struct kernel_param *kp);
/* Returns length written or -errno. Buffer is 4k (ie. be short!) */
int (*get)(char *buffer, const struct kernel_param *kp);
/* Optional function to free kp->arg when module unloaded. */
void (*free)(void *arg);
};
struct kernel_param {
const char *name;
const struct kernel_param_ops *ops;
u16 perm;
s16 level;
union {
void *arg;
const struct kparam_string *str;
const struct kparam_array *arr;
};
};
/* Special one for strings we want to copy into */
struct kparam_string {
unsigned int maxlen;
char *string;
};
/* Special one for arrays */
struct kparam_array
{
unsigned int max;
unsigned int elemsize;
unsigned int *num;
const struct kernel_param_ops *ops;
void *elem;
};
/**
* module_param - typesafe helper for a module/cmdline parameter
* @value: the variable to alter, and exposed parameter name.
* @type: the type of the parameter
* @perm: visibility in sysfs.
*
* @value becomes the module parameter, or (prefixed by KBUILD_MODNAME and a
* ".") the kernel commandline parameter. Note that - is changed to _, so
* the user can use "foo-bar=1" even for variable "foo_bar".
*
* @perm is 0 if the the variable is not to appear in sysfs, or 0444
* for world-readable, 0644 for root-writable, etc. Note that if it
* is writable, you may need to use kparam_block_sysfs_write() around
* accesses (esp. charp, which can be kfreed when it changes).
*
* The @type is simply pasted to refer to a param_ops_##type and a
* param_check_##type: for convenience many standard types are provided but
* you can create your own by defining those variables.
*
* Standard types are:
* byte, short, ushort, int, uint, long, ulong
* charp: a character pointer
* bool: a bool, values 0/1, y/n, Y/N.
* invbool: the above, only sense-reversed (N = true).
*/
#define module_param(name, type, perm) \
module_param_named(name, name, type, perm)
/**
* module_param_named - typesafe helper for a renamed module/cmdline parameter
* @name: a valid C identifier which is the parameter name.
* @value: the actual lvalue to alter.
* @type: the type of the parameter
* @perm: visibility in sysfs.
*
* Usually it's a good idea to have variable names and user-exposed names the
* same, but that's harder if the variable must be non-static or is inside a
* structure. This allows exposure under a different name.
*/
#define module_param_named(name, value, type, perm) \
param_check_##type(name, &(value)); \
module_param_cb(name, &param_ops_##type, &value, perm); \
__MODULE_PARM_TYPE(name, #type)
/**
* module_param_cb - general callback for a module/cmdline parameter
* @name: a valid C identifier which is the parameter name.
* @ops: the set & get operations for this parameter.
* @perm: visibility in sysfs.
*
* The ops can have NULL set or get functions.
*/
#define module_param_cb(name, ops, arg, perm) \
__module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, -1)
/**
* <level>_param_cb - general callback for a module/cmdline parameter
* to be evaluated before certain initcall level
* @name: a valid C identifier which is the parameter name.
* @ops: the set & get operations for this parameter.
* @perm: visibility in sysfs.
*
* The ops can have NULL set or get functions.
*/
#define __level_param_cb(name, ops, arg, perm, level) \
__module_param_call(MODULE_PARAM_PREFIX, name, ops, arg, perm, level)
#define core_param_cb(name, ops, arg, perm) \
__level_param_cb(name, ops, arg, perm, 1)
#define postcore_param_cb(name, ops, arg, perm) \
__level_param_cb(name, ops, arg, perm, 2)
#define arch_param_cb(name, ops, arg, perm) \
__level_param_cb(name, ops, arg, perm, 3)
#define subsys_param_cb(name, ops, arg, perm) \
__level_param_cb(name, ops, arg, perm, 4)
#define fs_param_cb(name, ops, arg, perm) \
__level_param_cb(name, ops, arg, perm, 5)
#define device_param_cb(name, ops, arg, perm) \
__level_param_cb(name, ops, arg, perm, 6)
#define late_param_cb(name, ops, arg, perm) \
__level_param_cb(name, ops, arg, perm, 7)
/* On alpha, ia64 and ppc64 relocations to global data cannot go into
read-only sections (which is part of respective UNIX ABI on these
platforms). So 'const' makes no sense and even causes compile failures
with some compilers. */
#if defined(CONFIG_ALPHA) || defined(CONFIG_IA64) || defined(CONFIG_PPC64)
#define __moduleparam_const
#else
#define __moduleparam_const const
#endif
/* This is the fundamental function for registering boot/module
parameters. */
#define __module_param_call(prefix, name, ops, arg, perm, level) \
/* Default value instead of permissions? */ \
static const char __param_str_##name[] = prefix #name; \
static struct kernel_param __moduleparam_const __param_##name \
__used \
__attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \
= { __param_str_##name, ops, VERIFY_OCTAL_PERMISSIONS(perm), \
level, { arg } }
/* Obsolete - use module_param_cb() */
#define module_param_call(name, set, get, arg, perm) \
static struct kernel_param_ops __param_ops_##name = \
{ 0, (void *)set, (void *)get }; \
__module_param_call(MODULE_PARAM_PREFIX, \
name, &__param_ops_##name, arg, \
(perm) + sizeof(__check_old_set_param(set))*0, -1)
/* We don't get oldget: it's often a new-style param_get_uint, etc. */
static inline int
__check_old_set_param(int (*oldset)(const char *, struct kernel_param *))
{
return 0;
}
/**
* kparam_block_sysfs_write - make sure a parameter isn't written via sysfs.
* @name: the name of the parameter
*
* There's no point blocking write on a paramter that isn't writable via sysfs!
*/
#define kparam_block_sysfs_write(name) \
do { \
BUG_ON(!(__param_##name.perm & 0222)); \
__kernel_param_lock(); \
} while (0)
/**
* kparam_unblock_sysfs_write - allows sysfs to write to a parameter again.
* @name: the name of the parameter
*/
#define kparam_unblock_sysfs_write(name) \
do { \
BUG_ON(!(__param_##name.perm & 0222)); \
__kernel_param_unlock(); \
} while (0)
/**
* kparam_block_sysfs_read - make sure a parameter isn't read via sysfs.
* @name: the name of the parameter
*
* This also blocks sysfs writes.
*/
#define kparam_block_sysfs_read(name) \
do { \
BUG_ON(!(__param_##name.perm & 0444)); \
__kernel_param_lock(); \
} while (0)
/**
* kparam_unblock_sysfs_read - allows sysfs to read a parameter again.
* @name: the name of the parameter
*/
#define kparam_unblock_sysfs_read(name) \
do { \
BUG_ON(!(__param_##name.perm & 0444)); \
__kernel_param_unlock(); \
} while (0)
#ifdef CONFIG_SYSFS
extern void __kernel_param_lock(void);
extern void __kernel_param_unlock(void);
#else
static inline void __kernel_param_lock(void)
{
}
static inline void __kernel_param_unlock(void)
{
}
#endif
#ifndef MODULE
/**
* core_param - define a historical core kernel parameter.
* @name: the name of the cmdline and sysfs parameter (often the same as var)
* @var: the variable
* @type: the type of the parameter
* @perm: visibility in sysfs
*
* core_param is just like module_param(), but cannot be modular and
* doesn't add a prefix (such as "printk."). This is for compatibility
* with __setup(), and it makes sense as truly core parameters aren't
* tied to the particular file they're in.
*/
#define core_param(name, var, type, perm) \
param_check_##type(name, &(var)); \
__module_param_call("", name, &param_ops_##type, &var, perm, -1)
#endif /* !MODULE */
/**
* module_param_string - a char array parameter
* @name: the name of the parameter
* @string: the string variable
* @len: the maximum length of the string, incl. terminator
* @perm: visibility in sysfs.
*
* This actually copies the string when it's set (unlike type charp).
* @len is usually just sizeof(string).
*/
#define module_param_string(name, string, len, perm) \
static const struct kparam_string __param_string_##name \
= { len, string }; \
__module_param_call(MODULE_PARAM_PREFIX, name, \
&param_ops_string, \
.str = &__param_string_##name, perm, -1); \
__MODULE_PARM_TYPE(name, "string")
/**
* parameq - checks if two parameter names match
* @name1: parameter name 1
* @name2: parameter name 2
*
* Returns true if the two parameter names are equal.
* Dashes (-) are considered equal to underscores (_).
*/
extern bool parameq(const char *name1, const char *name2);
/**
* parameqn - checks if two parameter names match
* @name1: parameter name 1
* @name2: parameter name 2
* @n: the length to compare
*
* Similar to parameq(), except it compares @n characters.
*/
extern bool parameqn(const char *name1, const char *name2, size_t n);
/* Called on module insert or kernel boot */
extern char *parse_args(const char *name,
char *args,
const struct kernel_param *params,
unsigned num,
s16 level_min,
s16 level_max,
int (*unknown)(char *param, char *val,
const char *doing));
/* Called by module remove. */
#ifdef CONFIG_SYSFS
extern void destroy_params(const struct kernel_param *params, unsigned num);
#else
static inline void destroy_params(const struct kernel_param *params,
unsigned num)
{
}
#endif /* !CONFIG_SYSFS */
/* All the helper functions */
/* The macros to do compile-time type checking stolen from Jakub
Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
#define __param_check(name, p, type) \
static inline type __always_unused *__check_##name(void) { return(p); }
extern struct kernel_param_ops param_ops_byte;
extern int param_set_byte(const char *val, const struct kernel_param *kp);
extern int param_get_byte(char *buffer, const struct kernel_param *kp);
#define param_check_byte(name, p) __param_check(name, p, unsigned char)
extern struct kernel_param_ops param_ops_short;
extern int param_set_short(const char *val, const struct kernel_param *kp);
extern int param_get_short(char *buffer, const struct kernel_param *kp);
#define param_check_short(name, p) __param_check(name, p, short)
extern struct kernel_param_ops param_ops_ushort;
extern int param_set_ushort(const char *val, const struct kernel_param *kp);
extern int param_get_ushort(char *buffer, const struct kernel_param *kp);
#define param_check_ushort(name, p) __param_check(name, p, unsigned short)
extern struct kernel_param_ops param_ops_int;
extern int param_set_int(const char *val, const struct kernel_param *kp);
extern int param_get_int(char *buffer, const struct kernel_param *kp);
#define param_check_int(name, p) __param_check(name, p, int)
extern struct kernel_param_ops param_ops_uint;
extern int param_set_uint(const char *val, const struct kernel_param *kp);
extern int param_get_uint(char *buffer, const struct kernel_param *kp);
#define param_check_uint(name, p) __param_check(name, p, unsigned int)
extern struct kernel_param_ops param_ops_long;
extern int param_set_long(const char *val, const struct kernel_param *kp);
extern int param_get_long(char *buffer, const struct kernel_param *kp);
#define param_check_long(name, p) __param_check(name, p, long)
extern struct kernel_param_ops param_ops_ulong;
extern int param_set_ulong(const char *val, const struct kernel_param *kp);
extern int param_get_ulong(char *buffer, const struct kernel_param *kp);
#define param_check_ulong(name, p) __param_check(name, p, unsigned long)
extern struct kernel_param_ops param_ops_charp;
extern int param_set_charp(const char *val, const struct kernel_param *kp);
extern int param_get_charp(char *buffer, const struct kernel_param *kp);
#define param_check_charp(name, p) __param_check(name, p, char *)
/* We used to allow int as well as bool. We're taking that away! */
extern struct kernel_param_ops param_ops_bool;
extern int param_set_bool(const char *val, const struct kernel_param *kp);
extern int param_get_bool(char *buffer, const struct kernel_param *kp);
#define param_check_bool(name, p) __param_check(name, p, bool)
extern struct kernel_param_ops param_ops_invbool;
extern int param_set_invbool(const char *val, const struct kernel_param *kp);
extern int param_get_invbool(char *buffer, const struct kernel_param *kp);
#define param_check_invbool(name, p) __param_check(name, p, bool)
/* An int, which can only be set like a bool (though it shows as an int). */
extern struct kernel_param_ops param_ops_bint;
extern int param_set_bint(const char *val, const struct kernel_param *kp);
#define param_get_bint param_get_int
#define param_check_bint param_check_int
/**
* module_param_array - a parameter which is an array of some type
* @name: the name of the array variable
* @type: the type, as per module_param()
* @nump: optional pointer filled in with the number written
* @perm: visibility in sysfs
*
* Input and output are as comma-separated values. Commas inside values
* don't work properly (eg. an array of charp).
*
* ARRAY_SIZE(@name) is used to determine the number of elements in the
* array, so the definition must be visible.
*/
#define module_param_array(name, type, nump, perm) \
module_param_array_named(name, name, type, nump, perm)
/**
* module_param_array_named - renamed parameter which is an array of some type
* @name: a valid C identifier which is the parameter name
* @array: the name of the array variable
* @type: the type, as per module_param()
* @nump: optional pointer filled in with the number written
* @perm: visibility in sysfs
*
* This exposes a different name than the actual variable name. See
* module_param_named() for why this might be necessary.
*/
#define module_param_array_named(name, array, type, nump, perm) \
param_check_##type(name, &(array)[0]); \
static const struct kparam_array __param_arr_##name \
= { .max = ARRAY_SIZE(array), .num = nump, \
.ops = &param_ops_##type, \
.elemsize = sizeof(array[0]), .elem = array }; \
__module_param_call(MODULE_PARAM_PREFIX, name, \
&param_array_ops, \
.arr = &__param_arr_##name, \
perm, -1); \
__MODULE_PARM_TYPE(name, "array of " #type)
extern struct kernel_param_ops param_array_ops;
extern struct kernel_param_ops param_ops_string;
extern int param_set_copystring(const char *val, const struct kernel_param *);
extern int param_get_string(char *buffer, const struct kernel_param *kp);
/* for exporting parameters in /sys/module/.../parameters */
struct module;
#if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES)
extern int module_param_sysfs_setup(struct module *mod,
const struct kernel_param *kparam,
unsigned int num_params);
extern void module_param_sysfs_remove(struct module *mod);
#else
static inline int module_param_sysfs_setup(struct module *mod,
const struct kernel_param *kparam,
unsigned int num_params)
{
return 0;
}
static inline void module_param_sysfs_remove(struct module *mod)
{ }
#endif
#endif /* _LINUX_MODULE_PARAMS_H */
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