/*************************************************************************

> File Name: myshell.c

> Author: FengXin

> Mail: fengxinlinux@gmail.com

> Created Time: 2016年07月26日 星期二 09时08分30秒

************************************************************************/

#define _GNU_SOURCE

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

#include<math.h>

#include<sys/signal.h>

#include<unistd.h>

#include<sys/types.h>

#include<sys/wait.h>

#include<sys/stat.h>

#include<fcntl.h>

#include<dirent.h>

#include<pwd.h>

#include<signal.h>

#define NONE "\e[0m" //不加色，恢复终端颜色

#define L_CYAN "\e[1;36m" //深淡蓝色

#define L_PURPLE "\e[1;35m" //深紫色

#define normal 0 //一般的命令

#define out_redirect 1 //输出重定向

#define in_redirect 2 //输入重定向

#define have_pipe 3 //命令中有管道

#define have_cd 4 //cd命令

void pd_home(char buf[],struct passwd *psd) //判断当前路径是否含家目录，将家目录改为～

{

int len1; //记录当前目录路径长度

int len2; //记录用户主目录路径长度

int i;

int n=1; //记录是否路径含主目录

char mainpath[PATH_MAX+1]; //记录主目录路径

char temp[PATH_MAX+1];

strcpy(mainpath,psd->pw_dir);

len2=strlen(mainpath);

len1=strlen(buf);

for(i=0;i<len2;i++)

{

if(mainpath[i]!=buf[i])

n=0;

}

if(n)

{

strcpy(temp,buf);

buf[0]='~';

buf[1]='\0';

strcat(buf,(temp+len2));

}

}

void print_shell() //打印shell提示符

{

char cpname[32]; //记录主机名

struct passwd *psd; //记录用户信息

char buf[PATH_MAX+1]; //记录当前目录路径

psd=getpwuid(getuid());

printf(L_CYAN"%s"NONE,psd->pw_name); //输出用户名

printf(L_CYAN"@"NONE);

if(gethostname(cpname, sizeof(cpname))==-1)

{

perror("get computer name error\n");

exit(1);

}

printf(L_CYAN"%s"NONE,cpname); //输出主机名

printf(":");

if(getcwd(buf,sizeof(buf))==NULL)

{

perror("get cwd error\n");

exit(1);

}

pd_home(buf,psd); //判断主目录

printf(L_PURPLE"%s"NONE,buf); //输出当前目录

if(getuid()==0)

printf("#");

else

printf("$ ");

}

void input_command(char* buf) //命令输入

{

int len=0;

int ch;

ch=getchar();

while(len<256&&ch!='\n')

{

buf[len++]=ch;

ch=getchar();

}

if(len==256)

{

printf("commod is too long \n");

exit(1);

}

buf[len]='\0';

}

void explain_command(char* buf,int* sum,char arglist[100][256]) //解析命令，分开存储

{

int i=0;

int s=0;

while(buf[i]==' '&&buf[i]!='\0')

i++;

while(buf[i]!='\0')

{

if(buf[i]!=' ')

s++;

else

{

strncpy(arglist[*sum],buf+i-s,s);

arglist[*sum][s]='\0';

s=0;

*sum=*sum+1;

}

i++;

}

if(s!=0)

{

strncpy(arglist[*sum],buf+i-s,s);

arglist[*sum][s]='\0';

*sum=*sum+1;

}

}

void cd_command(char**arg) //执行cd命令

{

int i;

char path[PATH_MAX]; //记录更改的路径

struct passwd *psd; //记录用户信息

psd=getpwuid(getuid());

if(arg[1]==NULL||(strcmp(arg[1],"~")==0))

{

strcpy(path,psd->pw_dir);

if(chdir(path)==-1)

{

printf("路径错误\n");

return;

}

}

else

{

strcpy(path,arg[1]);

if(chdir(path)==-1)

{

printf("路径错误\n");

return;

}

}

}

int find_command(char* command) //查找命令是否存在

{

char*path[]={"./","/bin","/usr/bin"};

DIR* dp;

struct dirent * dir;

int i=0;

if(strncmp(command,"./",2)==0)

command=command+2;

for(i=0;i<3;i++)

{

if((dp=opendir(path[i]))==NULL)

{

printf("opendir error\n");

return 0;

}

while((dir=readdir(dp))!=NULL)

{

if(strcmp(command,dir->d_name)==0)

return 1;

}

closedir(dp);

}

return 0;

}

void do_command(int sum,char arglist[100][256]) //执行命令

{

int flag =0; //若flag>1,说明命令中含多个>,<,|或格式不正确

int how=0; //记录命令中是否含有>,<,|

int background=0; //记录命令中是否有&

pid_t pid;

int fd;

int i;

char* file; //记录文件名

char** arg; //记录命令

char** argnext; // 记录管道命令

arg=(char**)malloc(sizeof(char*)*(sum+1));

argnext=(char**)malloc(sizeof(char*)*(sum+1));

for(i=0;i<sum;i++) //将命令取出

arg[i]=arglist[i];

arg[i]=NULL;

if(strcmp(arg[0],"cd")==0) //判断是否cd命令

{

cd_command(arg);

return;

}

if(strcmp(arg[0],"ls")==0) //给ls命令默认设置为--color=auto

{

i=0;

while(arg[i]!=NULL)

i++;

if(strcmp(arg[i-1],"&")==0)

{

arg[i-1]="--color=auto";

arg[i]="&";

arg[i+1]=NULL;

}

else

{

arg[i]="--color=auto";

arg[++i]=NULL;

}

}

for(i=0;arg[i]!=NULL;i++) //判断是否含有&

{

if(strcmp(arg[i],"&")==0)

{

if(arg[i+1]!=NULL&&strcmp(arg[0],"ls")!=0)

{

printf("wrong command\n");

return;

}

else

{

background=1;

arg[i]=NULL;

break;

}

}

}

for(i=0;arg[i]!=NULL;i++) //判断是否有>,<,|

{

if(strcmp(arg[i],">")==0)

{

flag++;

how=out_redirect;

if(i==0)

flag++;

if(i==sum-1)

flag++;

}

if(strcmp(arg[i],"<")==0)

{

flag++;

how=in_redirect;

if(i==0)

flag++;

if(i==sum-1)

flag++;

}

if(strcmp(arg[i],"|")==0)

{

flag++;

how=have_pipe;

if(i==0)

flag++;

if(arg[i+1]==NULL)

flag++;

}

}

if(flag>1)

{

printf("wrong command\n");

return;

}

if(how==out_redirect)

{

for(i=0;arg[i]!=NULL;i++)

if(strcmp(arg[i],">")==0)

break;

file=arg[i+1];

arg[i]=NULL;

}

if(how==in_redirect)

{

for(i=0;arg[i]!=NULL;i++)

if(strcmp(arg[i],"<")==0)

break;

file=arg[i+1];

arg[i]=NULL;

}

if(how==have_pipe)

{

for(i=0;arg[i]!=NULL;i++)

if(strcmp(arg[i],"|")==0)

break;

arg[i]=NULL;

int j=i+1;

for(j;arg[j]!=NULL;j++)

argnext[j-i-1]=arg[j];

argnext[j-i-1]=arg[j];

}

if((pid=fork())<0)

{

printf("creat process error \n");

return;

}

switch(how)

{

case normal:

if(pid==0)

{

if(!find_command(arg[0]))

{

printf("未找到'%s'命令\n",arg[0]);

exit(1);

}

execvp(arg[0],arg);

exit(0);

}

break;

case out_redirect:

if(pid==0)

{

if(!find_command(arg[0]))

{

printf("未找到'%s'命令\n",arg[0]);

exit(1);

}

if((fd=open(file,O_RDWR|O_CREAT|O_TRUNC,0644))==-1)

{

printf("creat file error\n");

exit(1);

}

if (dup2(fd,1) < 0) {

perror("dup2");

}

if(execvp(arg[0],arg)==-1)

{

printf("do command error\n");

exit(1);

}

exit(0);

}

break;

case in_redirect:

if(pid==0)

{

if(!find_command(arg[0]))

{

printf("未找到'%s'命令\n",arg[0]);

exit(1);

}

if((fd=open(file,O_RDWR))==-1)

{

printf("read file error\n");

exit(1);

}

dup2(fd,0);

execvp(arg[0],arg);

exit(0);

}

break;

case have_pipe:

if(pid==0)

{

int pid2;

int fd2;

if((pid2=fork())<0)

{

printf("fork2 error\n");

exit(1);

}

if(pid2==0)

{

if(!find_command(arg[0]))

{

printf("未找到'%s'命令\n",arg[0]);

return;

}

if((fd2=open("/tmp/temp.txt",O_RDWR|O_CREAT|O_TRUNC,0644))==-1)

{

printf("open dir error\n");

exit(0);

}

dup2(fd2,1);

execvp(arg[0],arg);

exit(0);

}

if(waitpid(pid2,NULL,0)==-1)

printf("wait for child process error\n");

if(!find_command(argnext[0]))

{

printf("未找到命令'%s'\n",argnext[0]);

return;

}

if((fd=open("/tmp/temp.txt",O_RDONLY))==-1)

printf("open file error\n");

dup2(fd,0);

execvp(argnext[0],argnext);

exit(0);

}

default:

break;

}

if(background)

{

printf("[process id %d]\n",pid);

return;

}

else

if(waitpid(pid,NULL,0)==-1)

{

printf("wait for child process error\n");

return;

}

}

int main()

{

int i;

int sum=0;

char arglist[100][256];

char* buf=NULL;

// signal(SIGTTIN,SIG_IGN); //忽略终端STOP信号

// signal(SIGTTOU,SIG_IGN);

// signal(SIGTSTP,SIG_IGN);

// signal(SIGHUP,SIG_IGN);

buf=(char*)malloc(sizeof(char)*256);

while(1)

{

memset(buf,0,256);

print_shell();

input_command(buf);

if(strcmp(buf,"exit")==0||strcmp(buf,"logout")==0)

break;

for(i=0;i<100;i++)

arglist[i][0]='\0';

sum=0;

explain_command(buf,&sum,arglist);

do_command(sum,arglist);

}

if(buf!=NULL)

free(buf);

exit(0);

}