目录
内核版本：
开始：
1、编写sys.c
/usr/src/linux-4.18.11/kernel/sys.c
添加：
#include <linux/linkage.h> SYSCALL_DEFINE2(test_one, int, count, const char __user *, buf) { char *p; printk("This is Syscall Test One.\n"); printk("buf addr is %p \n",buf); if(count > 1024) { printk("Your input str is too long.\n"); return 1; } p = (char *)kmalloc(sizeof(char) * count, GFP_KERNEL); if(!copy_from_user(p, buf, count)) { printk("input is %s \n", p); } kfree(p); return 1; } SYSCALL_DEFINE1(test_four, int, num) { printk("This is Syscall Test Four.\n"); printk("Four: Your input num is %d \n", num); return 1; }
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2、编写syscalls.h
/usr/src/linux-4.18.11/include/linux/syscalls.h
添加：
asmlinkage long sys_test_one(int count, const char __user *buf); asmlinkage long sys_test_four(int num);
3、编写syscall_64.tbl
/usr/src/linux-4.18.9/arch/x86/entry/syscalls/syscall_64.tbl
添加：
335 common test_one __x64_sys_test_one 338 common test_four __x64_sys_test_four
4、编译启动映像
make bzImage
5、编译模块
make modules
6.1、先安装模块
make modules_install
6.2、安装内核
make install
7、update-grub2 命令会帮我们自动修改grub
8、重启系统
sudo reboot
9、编写测试用例：
test_one.c
#include<stdio.h> #include<unistd.h> #include<string.h> int main(int argc, char * argv[]) { long ret; char *buf = "335 syscall"; printf("buf addr is %p \n", buf); ret = syscall(335, strlen(buf) + 1, buf); if (ret == 1) { printf("Syscall Succeed!\n"); } else { printf("Syscall Failed!\n"); } return 0; }
test_four.c:
#include<stdio.h> #include<unistd.h> int main(int argc, char * argv[]) { long ret; int num = 338; ret = syscall(338, num); if (ret == 1) { printf("Syscall Succeed!\n"); } else { printf("Syscall Failed!\n"); } return 0; }
10、测试
./test_one
dmesg:
./test_four
dmesg:
成功！
参考：Implementing a System Call on Linux 2.6 for i386
