I. Driver Module Transfer Parameters
1. Pass a single parameter
(1) Location: in include/linux/moduleparam.h under the source directory
(2) Function prototype
/** * 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)
(3) Parameters
module_param(name, type, perm)
Name: the name of the module parameter
Type: Data type of module parameters (supporting int long short uint ulong ushort type)
perm: Access permissions for module parameters (S_IRUSR parameter means that all file owners are readable)
2. Passing multiple parameters
(1) Function prototype
/** * 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)
(2) Parameters
module_param_array(name, type, nump, perm)
Name: the name of the module parameter
Type: Data type of module parameters (supporting int long short uint ulong ushort type)
nump: The address that holds the number of parameters is an address
perm: Access permissions for module parameters (S_IRUSR parameter means that all file owners are readable)
II. Test routines
1,module_param.c
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/stat.h>
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("SKYFALL");
static int module_arg1,module_arg2;
static int int_array[50];
static int int_num;
module_param(module_arg1,int,S_IRUSR);
module_param(module_arg2,int,S_IRUSR);
module_param_array(int_array,int,&int_num,S_IRUSR);
static int __init skyfall_init(void)
{
int i;
printk("%s,%d\n",__func__,__LINE__);
printk(KERN_EMERG "module_arg1 is %d!\n",module_arg1);
printk(KERN_EMERG "module_arg2 is %d!\n",module_arg2);
for(i = 0; i < int_num; i++)
{
printk(KERN_EMERG "int_array[%d] is %d!\n",i,int_array[i]);
}
printk(KERN_EMERG "skyfall dirver enter!\n");
return 0;
}
static void __exit skyfall_exit(void)
{
printk("%s,%d\n",__func__,__LINE__);
printk(KERN_EMERG "skyfall world exit!\n");
return ;
}
module_init(skyfall_init);
module_exit(skyfall_exit);
2. Makefile file file
#!/bin/bash
$(warning KERNELRELEASE = $(KERNELRELEASE))
ifeq ($(KERNELRELEASE),)
#The source path of the kernel,?= conditional assignment, uname-r gets the version number of the kernel
KERNELDIR ?= /home/mint/itop/linux_3.0
# := assign immediately to get the current absolute path
PWD := $(shell pwd)
# - C switch working path, $(MAKE) = make
modules:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
clean:
rm -rf *.o *~ core .depend .*.cmd *.ko *.mod.c .tmp_versions Module* modules*
.PHONY: modules clean
else
# Generating module
obj-m := module_param.o
endif
3. Driver files generated by compilation
4. Loading test
insmod module_param.ko module_arg1=10 module_arg2=20 int_array=11,12,13,14,15,16,17,18
5. Results of Query Loading
cat /sys/module/module_param/parameters/xxx
6. Unloading Drive
rmmod module_para
3. Parametric perm permissions
position: In the source directory include/linux/stat.h in
#ifndef _LINUX_STAT_H
#define _LINUX_STAT_H
#ifdef __KERNEL__
#include <asm/stat.h>
#endif
#if defined(__KERNEL__) || !defined(__GLIBC__) || (__GLIBC__ < 2)
#define S_IFMT 00170000
#define S_IFSOCK 0140000
#define S_IFLNK 0120000
#define S_IFREG 0100000
#define S_IFBLK 0060000
#define S_IFDIR 0040000
#define S_IFCHR 0020000
#define S_IFIFO 0010000
#define S_ISUID 0004000
#define S_ISGID 0002000
#define S_ISVTX 0001000
#define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
#define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
#define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#define S_ISCHR(m) (((m) & S_IFMT) == S_IFCHR)
#define S_ISBLK(m) (((m) & S_IFMT) == S_IFBLK)
#define S_ISFIFO(m) (((m) & S_IFMT) == S_IFIFO)
#define S_ISSOCK(m) (((m) & S_IFMT) == S_IFSOCK)
#define S_IRWXU 00700// File owner has full permissions
#define S_IRUSR 00400// File Owner Readable
#define S_IWUSR 00200// File Owner Writable
#define S_IXUSR 00100// File Owner Executable
#define S_IRWXG 00070/ Users in the same group as the file owner have full privileges
#define S_IRGRP 00040// Readable by users in the same group as the file owner
#define S_IWGRP 00020// Writable by users in the same group as the file owner
#define S_IXGRP 00010// / Users in the same group as the file owner can execute
#define S_IRWXO 00007// Users in different groups from the file owner have full privileges
#define S_IROTH 00004// User Readable in Different Groups from File Owner
#define S_IWOTH 00002// Writable by users in different groups from the file owner
#define S_IXOTH 00001// / Users in different groups from the file owner can execute
#endif
#ifdef __KERNEL__
#define S_IRWXUGO (S_IRWXU|S_IRWXG|S_IRWXO)
#define S_IALLUGO (S_ISUID|S_ISGID|S_ISVTX|S_IRWXUGO)
#define S_IRUGO (S_IRUSR|S_IRGRP|S_IROTH)
#define S_IWUGO (S_IWUSR|S_IWGRP|S_IWOTH)
#define S_IXUGO (S_IXUSR|S_IXGRP|S_IXOTH)
#define UTIME_NOW ((1l << 30) - 1l)
#define UTIME_OMIT ((1l << 30) - 2l)
#include <linux/types.h>
#include <linux/time.h>
struct kstat {
u64 ino;
dev_t dev;
umode_t mode;
unsigned int nlink;
uid_t uid;
gid_t gid;
dev_t rdev;
loff_t size;
struct timespec atime;
struct timespec mtime;
struct timespec ctime;
unsigned long blksize;
unsigned long long blocks;
};
#endif
#endif