其实这个代码与具体开发板无关，想在内核空间和用户空间传递结构体数据，第一块的write已经验证成功，但是read一直报Segmentation fault错误，已经调了好几天。想请教大家，谢谢大家，具体代码如下：
驱动代码：
C/C++ code?#include <linux/init.h> #include <linux/module.h> #include <linux/device.h> #include <linux/kdev_t.h> #include <linux/timer.h> #include <asm/uaccess.h> #include <asm/io.h> #include <linux/fs.h> /* Kernel Version: Linux 2.6.38 Arm Version: Mini 6410 */ #define MyPrintk printk struct my_data_structure { unsigned int number; char *name; unsigned long count; }; static dev_t Leds_Major ; static char * DEVICE_NAME = "DataTransfemission"; static struct class *leds_class; static struct my_data_structure my_own_data[] = { {1,"Jack",0}, {2,"Tom",0}, {3,"Kobe",0}, {4,"Xiaohong",0} }; static ssize_t data_read(struct file *file, char __user * buffer, size_t count, loff_t *pos) { struct my_data_structure temp_data= {6,"Jack",0}; MyPrintk("123\n"); int ret = copy_to_user(buffer,(void *)&temp_data, sizeof(temp_data)); if (ret != 0){ MyPrintk("read error\n"); } return 0; } static ssize_t data_write(struct file *flie, const char __user * buffer, size_t count, loff_t *pos) { struct my_data_structure user_data; int ret = copy_from_user((void *)&user_data, buffer, count); if (ret != 0){ MyPrintk("write error\n"); } MyPrintk (KERN_EMERG "Kernel from user data: %i, %s, %lu\n", user_data.number, user_data.name, user_data.count); return 0; } static int data_open(struct file *file, struct node *nodes) { return 0; } static struct file_operations s3c64XX_leds_fops = { .owner = THIS_MODULE, .read = data_read, .write = data_write, .open = data_open, }; static int myleds_init(void) { Leds_Major = register_chrdev(Leds_Major,DEVICE_NAME , &s3c64XX_leds_fops); if(Leds_Major < 0){ MyPrintk (KERN_EMERG "Sorry, Can not register the data trsanmission device!\n"); } MyPrintk (KERN_EMERG " Register the data trsanmission leds device\n"); leds_class = class_create(THIS_MODULE, DEVICE_NAME); device_create(leds_class, NULL , MKDEV(Leds_Major, 0), NULL,DEVICE_NAME); return 0; } static void myleds_exit(void) { unregister_chrdev(Leds_Major, DEVICE_NAME); device_destroy(leds_class, MKDEV(Leds_Major, 0)); class_destroy(leds_class); MyPrintk (KERN_EMERG "Data transmission Linux Byebye\n"); } module_init(myleds_init); module_exit(myleds_exit); MODULE_LICENSE("GPL");
应用层代码如下
C/C++ code?#include<stdio.h> #include<fcntl.h> #include<unistd.h> #include<string.h> #include <stdlib.h> struct my_data_structure { unsigned int number; char *name; unsigned long count; }; int main(int argc, char **argv) { int fd; int ret; fd = open("/dev/DataTransfemission", O_RDWR); if (fd < 0){ printf("Sorry, can't open!\n"); } struct my_data_structure my_write_data = {6,"weipeng",1}; printf("struct sizeof %d, %d\n", sizeof(my_write_data ), sizeof(struct my_data_structure )); ret = write(fd, &my_write_data , sizeof(my_write_data)); if(ret < 0){ printf("Sorry, write2 error!\n"); } struct my_data_structure *my_write_data2 = (struct my_data_structure*)malloc(sizeof(struct my_data_structure)); printf("struct* sizeof %d, %d\n", sizeof(my_write_data2), sizeof(struct my_data_structure )); my_write_data2->number = 5; my_write_data2->name ="xiangwei"; my_write_data2->count = 2; ret = write(fd, my_write_data2 , sizeof(struct my_data_structure)); if(ret < 0){ printf("Sorry, write2 error!\n"); } printf("read 1!\n"); struct my_data_structure my_read_data; ret = read(fd, &my_read_data , sizeof(my_read_data)); if(ret < 0){ printf("Sorry, read1 error!\n"); } printf("my_read_data: %ui, %s, %ul\n", my_read_data.number, my_read_data.name, my_read_data.count); printf("read 3!\n"); struct my_data_structure* my_read_data3 =(struct my_data_structure*)malloc(sizeof(struct my_data_structure)); ret = read(fd, my_read_data3 , sizeof(struct my_data_structure)); if(ret < 0){ printf("Sorry, read3 error!\n"); } printf("my_read_data3: %ui, %s, %ul\n", my_read_data3->number, my_read_data3->name, my_read_data3->count); printf("read 2!\n"); struct my_data_structure* my_read_data2; ret = read(fd, my_read_data2 , sizeof(struct my_data_structure)); if(ret < 0){ printf("Sorry, read2 error!\n"); } printf("my_read_data2: %ui, %s, %ul\n", my_read_data2->number, my_read_data2->name, my_read_data2->count); free(my_write_data2); free(my_read_data2); free(my_read_data3); return 0; }
我没调试你的程序，但你的程序肯定是不能运行的，
printf("my_read_data: %ui, %s, %ul\n", my_read_data.number, my_read_data.name, my_read_data.count);肯定要段错误的
my_read_data.name的地址在内核
struct my_data_structure{ unsigned int number; char *name; unsigned long count;};
这样的定义是不能将name的数据传送到用户端
你需要把name改成char数组。