添加系统调用实验报告.doc

一、构建基本的实验环境1.1基本实验环境与前提条件Windows7 、Word 2010、Vmware WorkStation 8.5、AdobeReaderReadHatLinux 9.0，gcc，viLinux内核V2.4.181.2虚拟机的安装及使用1.3将Linux 内核源代码及配置文件传送给虚拟机上的Red Hat Linux V9.0 系统配置网络时遇到这个问题，Determining IP information for eth0. failed; no link present. Check cable？ 通过查找资料发现是系统的Bug，解决方法如下：到/etc/sysconfig/network-scripts/ifcfg-eth0在文件最后一行中加入check_link_down () return 1; 另外如果存在/etc/sysconfig/networking/profiles/default/ifcfg-eth0 文件，则同样在其中加入这一段东西即可，然后重启系统。设置网络为DHCP，重新启动就可以，啦，直接上图最后将内核代码下载到/root目录下二、Linux 内核编译、配置与调试2.1 内核配置与编译2.1.1、解压内核源代码文件tar -zxf linux-2.4.18.tar.gz2.1.2、解压后如下 2.1.3、拷贝linux，命名为linux-2.4.18cp -r linux linux-2.4.18 2.1.4、移动config-2.4.18forMP.txt到linux-2.4.18根目录，替换掉.config 2.1.5、进入linux-2.4.18目录，配置和编译内核模块 make oldconfig make dep make clean make bzImage make modules2.2 内核安装与测试 2.2.1安装内核映像文件 cp arch/i386/boot/bzImage /boot/vmlinux-2.4.18 2.2.2拷贝和安装Linux系统映射文件System.map,并创建其与系统映射文件System.map之间的符号链接2.2.3执行命令make modules_install 以安装可动态加载的内核模块 2.2.4添加启动项的配置 利用vi编辑器，vi grub.conf查看/ 所在的位置，为/dev/sda3 2.2.5reboot重新启动系统，从自己创建的内核启动系统启动后查看内核分别用uname r，和dmesg查看三、Linux 系统调用添加与实现3.1 在内核增加系统调用3.1.1结构体struct srz_rusage可声明如下：.struct srz_rusage struct timeval ru_utime; /* user time used */struct timeval ru_stime; /* system time used */long ru_majflt; /* major page faults */long ru_minflt; /* minor page faults */long ru_nswap; /* swaps */;3.1.2添加到linux-2.4.18/include/linux下的resource.h中3.1.3添加的系统调用名称为：int get_process_usage(pid_t, struct srz_rusage*);参考的getrusage和sys_getrusage的代码在linux-2.4.18/linux/kernel/sys.c下面3.1.4分析getrusage()和sys_getrusage()的源代码1)数据结构rusage 在头文件 resource.h中定义。structrusage struct timeval ru_utime;/* user time used */struct timeval ru_stime;/* system time used */longru_maxrss;/* maximum resident set size */longru_ixrss;/* integral shared memory size */longru_idrss;/* integral unshared data size */longru_isrss;/* integral unshared stack size */longru_minflt;/* page reclaims */longru_majflt;/* page faults */longru_nswap;/* swaps */longru_inblock;/* block input operations */longru_oublock;/* block output operations */longru_msgsnd;/* messages sent */longru_msgrcv;/* messages received */longru_nsignals;/* signals received */longru_nvcsw;/* voluntary context switches */longru_nivcsw;/* involuntary */;2)函数getrusage()的作用是获取系统资源使用情况。 /* * It would make sense to put struct rusage in the task_struct, * except that would make the task_struct be *really big*. After * task_struct gets moved into malloced memory, it would * make sense to do this. It will make moving the rest of the information * a lot simpler! (Which were not doing right now because were not * measuring them yet). * * This is SMP safe. Either we are called from sys_getrusage on ourselves * below (we know we arent going to exit/disappear and only we change our * rusage counters), or we are called from wait4() on a process which is * either stopped or zombied. In the zombied case the task wont get * reaped till shortly after the call to getrusage(), in both cases the * task being examined is in a frozen state so the counters wont change. * * FIXME! Get the fault counts properly! */int getrusage(struct task_struct *p, int who, struct rusage *ru)struct rusage r;memset(char *) &r, 0, sizeof(r);switch (who) case RUSAGE_SELF:r.ru_utime.tv_sec = CT_TO_SECS(p-times.tms_utime);r.ru_utime.tv_usec = CT_TO_USECS(p-times.tms_utime);r.ru_stime.tv_sec = CT_TO_SECS(p-times.tms_stime);r.ru_stime.tv_usec = CT_TO_USECS(p-times.tms_stime);r.ru_minflt = p-min_flt;r.ru_majflt = p-maj_flt;r.ru_nswap = p-nswap;break;case RUSAGE_CHILDREN:r.ru_utime.tv_sec = CT_TO_SECS(p-times.tms_cutime);r.ru_utime.tv_usec = CT_TO_USECS(p-times.tms_cutime);r.ru_stime.tv_sec = CT_TO_SECS(p-times.tms_cstime);r.ru_stime.tv_usec = CT_TO_USECS(p-times.tms_cstime);r.ru_minflt = p-cmin_flt;r.ru_majflt = p-cmaj_flt;r.ru_nswap = p-cnswap;break;default:r.ru_utime.tv_sec = CT_TO_SECS(p-times.tms_utime + p-times.tms_cutime);r.ru_utime.tv_usec = CT_TO_USECS(p-times.tms_utime + p-times.tms_cutime);r.ru_stime.tv_sec = CT_TO_SECS(p-times.tms_stime + p-times.tms_cstime);r.ru_stime.tv_usec = CT_TO_USECS(p-times.tms_stime + p-times.tms_cstime);r.ru_minflt = p-min_flt + p-cmin_flt;r.ru_majflt = p-maj_flt + p-cmaj_flt;r.ru_nswap = p-nswap + p-cnswap;break;return copy_to_user(ru, &r, sizeof(r) ? -EFAULT : 0;3)sys_getrusage()只是调用了内核函数getrusage()，是内核提供给用户的接口。asmlinkage long sys_getrusage(int who, struct rusage *ru)if (who != RUSAGE_SELF & who != RUSAGE_CHILDREN)return -EINVAL;return getrusage(current, who, ru);3.2 编写应用程序调用该系统（调用）过程 3.2.1在sys.c中添加函数get_process_usage()和系统调用函数sys_get_process_usage()的代码； 目录linux-2.4.18/kernel/sys.c intget_process_usage(structtask_struct*p,structsrz_rusage*ru)structsrz_rusager;memset(char*)&r,0,sizeof(r);/比上次的实验报告里，更新的内容printk(“The program(get_process_usage) is successful !n”);r.ru_utime.tv_sec=CT_TO_SECS(p-times.tms_utime);r.ru_utime.tv_usec=CT_TO_USECS(p-times.tms_utime);r.ru_stime.tv_sec=CT_TO_SECS(p-times.tms_stime); r.ru_stime.tv_usec=CT_TO_USECS(p-times.tms_stime); r.ru_minflt=p-min_flt; r.ru_majflt=p-maj_flt;r.ru_nswap=p-nswap;returncopy_to_user(ru,&r,sizeof(r)?-EFAULT:0; asmlinkagelongsys_get_process_usage(pid_tpid,structsrz_rusage*ru)structtask_struct*p;p=find_task_by_pid(pid);if(p)returnget_process_usage(p,ru);return-EINVAL;3)修改完源程序以后，下一个任务是使Linux内核知道该程序的存在。为了从已有的内核程序中增加到新的函数的连接，需要编辑两个文件。第一个要修改的文件是/root/linux-2.4.18/ include/asm-i386/unistd.h，该文件中包含了系统调用清单，用来给每个系统调用分配一个唯一的号码。应该将新的系统调用名称加到清单的最后，并给它分配号码序列中下一个可用的系统调用号。#define _NR_get_process_usage 238根据上图已知系统调用已经用到了237，我们用238 第二个要修改的文件是：/root/linux-2.4.18/arch/i386/kernel/entry.S，该文件中有类似.long SYMBOL_NAME()的清单, 该清单用来对sys_call_table数组进行初始化,该数组包含指向内核中每个系统调用的指针。我们在清单最后添加一行：.long SYMBOL_NAME(sys_get_process_usage)编译安装内核以后的启动界面四、编写程序调用新的系统调用4.1.1 程序一头文件/get_process_usag.h#include #include 源程序/ get_process_usag.c#include get_process_usag.h#include int get (pid_t pid);int main(int argc,char *argv) pid_t pid; pid=atoi(argv1); get (pid); return 1;int get (pid_t pid) struct srz_rusage ru; long r=0; if(pid=0) printf(n error: Pid must int!nn); return 0; r=syscall(238,pid,&ru); if(!r) printf(ShangRongZhu success!nn); printf(User_time :t%d seconds: %d msecondsn,ru.ru_utime.tv_sec,ru.ru_utime.tv_usec); printf(System_time :t%d seconds: %d mseconds n,ru.ru_stime.tv_sec,ru.ru_stime.tv_usec); printf(Min lost page:t%dn,ru.ru_minflt); printf(Max lost page:t%dn,ru.ru_majflt); printf(Change page times: t%dn,ru.ru_nswap); else printf(Error,cheak the pid: n,r);编译Gcc o testsyscall getpu_syscall.c执行./testsyscall pid_no执行结果Dmesg查看信息4.1.2程序二/ get_process_syscall2.c#include get_process_usag.h#include #define _NR_get_process_usage 238_syscall2(long,get_process_usage,pid_t,pid,struct srz_rusage *,ru)int get (pid_t pid);int main(int argc,char *argv) pid_t pid; pid=atoi(argv1); get (pid); return 1;int get (pid_t pid) struct srz_rusage ru; long r=0; if(pid=0) printf(n error: Pid must int!nn); return 0; r=get_process_usage(pid,&ru); if(!r) printf(ShangRongZhu success!nn); printf(User_time :t%d seconds: %d msecondsn,ru.ru_utime.tv_sec,ru.ru_utime.tv_usec); printf(System_time :t%d seconds: %d mseconds n,ru.ru_stime.tv_sec,ru.ru_stime.tv_usec); printf(Min lost page:t%dn,ru.ru_minflt); printf(Max lost page:t%dn,ru.ru_majflt); printf(Change page times: t%dn,ru.ru_nswap); else printf(Error,cheak the pid: n,r);执行结果如下编译Gcc -o testsyscall2 getpu_syscall2.c./testsyscall pid_nodmesg查看附件：源程序一：第一种实现方法/get_process_usag.h#include #include 源程序/ get_process_usag.c#include get_process_usag.h#include int get (pid_t pid);int main(int argc,char *argv) pid_t pid; pid=atoi(argv1); get (pid); return 1;int get (pid_t pid) struct srz_rusage ru; long r=0; if(pid=0) printf(n error: Pid must int!nn); return 0; r=syscall(238,pid,&ru); if(!r) printf(ShangRongZhu success!nn); printf(User_time :t%d seconds: %d msecondsn,ru.ru_utime.tv_sec,ru.ru_utime.tv_usec); printf(System_time :t%d seconds: %d mseconds n,ru.ru_stime.tv_sec,ru.ru_stime.tv_usec); printf(Min lost page:t%dn,ru.ru_minflt); printf(Max lost page:t%dn,ru.ru_majflt); printf(Change