diff options
Diffstat (limited to 'include/linux/moduleparam.h')
| -rw-r--r-- | include/linux/moduleparam.h | 288 |
1 files changed, 221 insertions, 67 deletions
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h index 82a9124f7d75..9d2f1837b3d8 100644 --- a/include/linux/moduleparam.h +++ b/include/linux/moduleparam.h @@ -31,20 +31,23 @@ static const char __module_cat(name,__LINE__)[] \ struct kernel_param; -/* Returns 0, or -errno. arg is in kp->arg. */ -typedef int (*param_set_fn)(const char *val, struct kernel_param *kp); -/* Returns length written or -errno. Buffer is 4k (ie. be short!) */ -typedef int (*param_get_fn)(char *buffer, struct kernel_param *kp); +struct kernel_param_ops { + /* 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); +}; /* Flag bits for kernel_param.flags */ #define KPARAM_ISBOOL 2 struct kernel_param { const char *name; + const struct kernel_param_ops *ops; u16 perm; u16 flags; - param_set_fn set; - param_get_fn get; union { void *arg; const struct kparam_string *str; @@ -63,12 +66,67 @@ struct kparam_array { unsigned int max; unsigned int *num; - param_set_fn set; - param_get_fn get; + const struct kernel_param_ops *ops; unsigned int elemsize; 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, ¶m_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, __same_type((arg), bool *), perm) + /* 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 @@ -80,10 +138,8 @@ struct kparam_array #endif /* This is the fundamental function for registering boot/module - parameters. perm sets the visibility in sysfs: 000 means it's - not there, read bits mean it's readable, write bits mean it's - writable. */ -#define __module_param_call(prefix, name, set, get, arg, isbool, perm) \ + parameters. */ +#define __module_param_call(prefix, name, ops, arg, isbool, perm) \ /* Default value instead of permissions? */ \ static int __param_perm_check_##name __attribute__((unused)) = \ BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2)) \ @@ -92,31 +148,87 @@ struct kparam_array static struct kernel_param __moduleparam_const __param_##name \ __used \ __attribute__ ((unused,__section__ ("__param"),aligned(sizeof(void *)))) \ - = { __param_str_##name, perm, isbool ? KPARAM_ISBOOL : 0, \ - set, get, { arg } } + = { __param_str_##name, ops, perm, isbool ? KPARAM_ISBOOL : 0, \ + { arg } } + +/* Obsolete - use module_param_cb() */ +#define module_param_call(name, set, get, arg, perm) \ + static struct kernel_param_ops __param_ops_##name = \ + { (void *)set, (void *)get }; \ + __module_param_call(MODULE_PARAM_PREFIX, \ + name, &__param_ops_##name, arg, \ + __same_type(arg, bool *), \ + (perm) + sizeof(__check_old_set_param(set))*0) + +/* 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; +} -#define module_param_call(name, set, get, arg, perm) \ - __module_param_call(MODULE_PARAM_PREFIX, \ - name, set, get, arg, \ - __same_type(*(arg), bool), perm) +/** + * 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) -/* Helper functions: type is byte, short, ushort, int, uint, long, - ulong, charp, bool or invbool, or XXX if you define param_get_XXX, - param_set_XXX and param_check_XXX. */ -#define module_param_named(name, value, type, perm) \ - param_check_##type(name, &(value)); \ - module_param_call(name, param_set_##type, param_get_##type, &value, perm); \ - __MODULE_PARM_TYPE(name, #type) +/** + * 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) -#define module_param(name, type, perm) \ - module_param_named(name, name, type, perm) +/** + * 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 (for param_set_##type and param_get_##type) + * @type: the type of the parameter * @perm: visibility in sysfs * * core_param is just like module_param(), but cannot be modular and @@ -126,23 +238,32 @@ struct kparam_array */ #define core_param(name, var, type, perm) \ param_check_##type(name, &(var)); \ - __module_param_call("", name, param_set_##type, param_get_##type, \ + __module_param_call("", name, ¶m_ops_##type, \ &var, __same_type(var, bool), perm) #endif /* !MODULE */ -/* Actually copy string: maxlen param is usually sizeof(string). */ +/** + * 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_set_copystring, param_get_string, \ + ¶m_ops_string, \ .str = &__param_string_##name, 0, perm); \ __MODULE_PARM_TYPE(name, "string") /* Called on module insert or kernel boot */ extern int parse_args(const char *name, char *args, - struct kernel_param *params, + const struct kernel_param *params, unsigned num, int (*unknown)(char *param, char *val)); @@ -162,72 +283,105 @@ static inline void destroy_params(const struct kernel_param *params, #define __param_check(name, p, type) \ static inline type *__check_##name(void) { return(p); } -extern int param_set_byte(const char *val, struct kernel_param *kp); -extern int param_get_byte(char *buffer, struct kernel_param *kp); +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 int param_set_short(const char *val, struct kernel_param *kp); -extern int param_get_short(char *buffer, struct kernel_param *kp); +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 int param_set_ushort(const char *val, struct kernel_param *kp); -extern int param_get_ushort(char *buffer, struct kernel_param *kp); +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 int param_set_int(const char *val, struct kernel_param *kp); -extern int param_get_int(char *buffer, struct kernel_param *kp); +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 int param_set_uint(const char *val, struct kernel_param *kp); -extern int param_get_uint(char *buffer, struct kernel_param *kp); +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 int param_set_long(const char *val, struct kernel_param *kp); -extern int param_get_long(char *buffer, struct kernel_param *kp); +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 int param_set_ulong(const char *val, struct kernel_param *kp); -extern int param_get_ulong(char *buffer, struct kernel_param *kp); +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 int param_set_charp(const char *val, struct kernel_param *kp); -extern int param_get_charp(char *buffer, struct kernel_param *kp); +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 *) /* For historical reasons "bool" parameters can be (unsigned) "int". */ -extern int param_set_bool(const char *val, struct kernel_param *kp); -extern int param_get_bool(char *buffer, struct kernel_param *kp); +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) \ static inline void __check_##name(void) \ { \ - BUILD_BUG_ON(!__same_type(*(p), bool) && \ - !__same_type(*(p), unsigned int) && \ - !__same_type(*(p), int)); \ + BUILD_BUG_ON(!__same_type((p), bool *) && \ + !__same_type((p), unsigned int *) && \ + !__same_type((p), int *)); \ } -extern int param_set_invbool(const char *val, struct kernel_param *kp); -extern int param_get_invbool(char *buffer, struct kernel_param *kp); +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) -/* Comma-separated array: *nump is set to number they actually specified. */ +/** + * 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) \ static const struct kparam_array __param_arr_##name \ - = { ARRAY_SIZE(array), nump, param_set_##type, param_get_##type,\ + = { ARRAY_SIZE(array), nump, ¶m_ops_##type, \ sizeof(array[0]), array }; \ __module_param_call(MODULE_PARAM_PREFIX, name, \ - param_array_set, param_array_get, \ + ¶m_array_ops, \ .arr = &__param_arr_##name, \ __same_type(array[0], bool), perm); \ __MODULE_PARM_TYPE(name, "array of " #type) -#define module_param_array(name, type, nump, perm) \ - module_param_array_named(name, name, type, nump, perm) - -extern int param_array_set(const char *val, struct kernel_param *kp); -extern int param_array_get(char *buffer, struct kernel_param *kp); +extern struct kernel_param_ops param_array_ops; -extern int param_set_copystring(const char *val, struct kernel_param *kp); -extern int param_get_string(char *buffer, struct kernel_param *kp); +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/parameters */ @@ -235,13 +389,13 @@ struct module; #if defined(CONFIG_SYSFS) && defined(CONFIG_MODULES) extern int module_param_sysfs_setup(struct module *mod, - struct kernel_param *kparam, + 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, - struct kernel_param *kparam, + const struct kernel_param *kparam, unsigned int num_params) { return 0; |