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-rw-r--r--include/linux/moduleparam.h288
1 files changed, 221 insertions, 67 deletions
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 82a9124..9d2f183 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, &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, __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, &param_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, \
+ &param_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, &param_ops_##type, \
sizeof(array[0]), array }; \
__module_param_call(MODULE_PARAM_PREFIX, name, \
- param_array_set, param_array_get, \
+ &param_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;
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