实验三系统调用修改以下文件 1. -------------------------- include目录下的unistd： ``` #define __NR_iam 72 #define __NR_whoami 73 int iam(const char* name); int whoami(char* name,unsigned int size); ``` -------------------------- include/liunx目录下的sys.h： ``` extern int sys_iam(); extern int sys_whoami(); ,sys_iam,sys_whoami ``` 2. -------------------------- kernel目录下的system_call.s： 72改为74 -------------------------- kernel目录下创建文件who.c： ``` #define __LIBRARY__ #include #include #include char usnm[64]={0}; int sys_iam(const char* name) { int result=0; int cnt; while(get_fs_byte(name+result) != '\0' && result<64) result++; if(result>23) return -EINVAL; else { for(cnt=0;cnt<=result;cnt++){usnm[cnt]=get_fs_byte(name+cnt);} return result; } } int sys_whoami(char* name, unsigned int size) { int result=0; int cnt; while(usnm[result] != '\0' && result<64) result++; if(result>size) return -1; else { for(cnt=0;cnt<=result;cnt++){put_fs_byte(usnm[cnt],(name+cnt));} return result; } } ``` -------------------------- kernel目录下MakeFile： ``` who.s who.o:who.c ../include/unistd.h ../include/linux/kernel.h \ ../include/errno.h ../include/asm/segment.h ``` 3. ---------------------- 在oslab目录下执行命令$ sudo ./mount-hdc 挂载虚拟机硬盘， oslab/hdc/usr/include目录下添加文件iam.c，whoami.c: iam.c ---------------------- ``` #define __LIBRARY__ #include #include #include _syscall1(int,iam,const char*,name) int main(int argc,char** argv){ if(argc>1){ if(iam(argv[1])<0){ return -1; }else{ printf("name is %s\n",argv[1]); } } return 0; } ``` whoami.c ---------------------- ``` #define __LIBRARY__ #include #include #include _syscall2(int,whoami,char*,name,unsigned int,size) int main(int argc,char** argv){ char namebuffer[32]={0}; int value=-1; if(argc){ value=whoami(namebuffer,24); printf("I am %s\n,whoami()=%d",namebuffer,value); } return 0; } ``` 将linux-0.11/include/unistd.h复制到hdc/usr/include目录下，将linux-0.11/include/linux/sys.h复制到hdc/usr/linux目录下，在oslab目录下执行命令$ sudo umount hdc 卸载虚拟硬盘。 linux-0.11目录下输入make, ../run,运行虚拟机编译链接 iam.c,whoami.c文件，运行 ![图片描述](https://dn-simplecloud.shiyanlou.com/uid/350078/1487384299951.png-wm)

“操作系统原理与实践”实验报告