linux下使用系统调用模拟SHELL

结构还算清晰，昨天的blog里已经大致说过了，不多解释了

RTFSC :)

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <string.h>
#include <wait.h>
#include <sys/stat.h>
#include <dirent.h>
#include <time.h>
#include <errno.h>

typedef struct command_struct{
int comargc;
char* command;
char* comargv[10];
}command_struct;

int com_inside(char*);
int search(char*,char*,char*);

int main(int argc,char** argv)
{
int flag;
int i,c;
int m,n;
int * status;
char cwd[255];
int exeflag;
char tempcom[10];
char full_pathname[64]="/home/yg/c_test/0921";
char pathname[64];
char scanargv[10][10]={};
command_struct com;
while(1)
{
if((int)getcwd(cwd,64)==-1)
printf("get cwd error");
printf("%s>",cwd);
/*begin init command_struct*/
for(m=0;m<10;m++)
{
for(n=0;n<10;n++)
{
scanargv[m]
=0;
}
}
i=0;
while((c=getchar())!='/n')
{
if(c!=' ')
{
scanargv[i][0]=c;
scanf("%s",scanargv[i++]+1);
}
else
{
scanf("%s",scanargv[i++]);
}
}
com.comargc=i-1;
com.command=scanargv[0];
i=0;
while(i<10)
{
com.comargv[i]=scanargv[i];
i++;
}
/*end init command_struct*/
if(com.command=="/n")continue;
if((strcmp(com.command,"quit")==0)||(strcmp(com.command,"exit")==0))exit(1);
if((flag=com_inside(com.command))==-1)exit(1);
else if(flag==1)continue;
else if(flag==0)
{
strcpy(tempcom,com.command);
if((exeflag=search(full_pathname,tempcom,pathname))==0)
printf("Bad command or file name/n");
else
{
if(fork()==0)
{
i=0;
while(i<=com.comargc)
{
argv[i]=com.comargv[i];
i++;
}
if(execve(pathname,argv,0)==-1)
{
printf("error is %s/n",strerror(errno));
}
}
else
{
wait(status);
}
}
}
}
return 1;
}

int com_inside(char* command)
{
if(command==NULL)return -1;
if(!(strcmp(command,"ok")))
{
printf("OK/n");
return 1;
}
if(!(strcmp(command,"ver")))
{
printf("0.0.0.1/n");
return 1;
}
return 0;
}

int search(char* path,char* name,char* full_pathname)
{
int flag;
int i;
char pathname[64]={};
DIR * dirp;
struct dirent * direntp;
strcpy(pathname,path);
i=0;
while(pathname[i]!=0)
{
i++;
}
if(pathname[i-1]!=47)
{
strcat(pathname,"/");
}
if((dirp=opendir(path)))
{
while((direntp=readdir(dirp))!=NULL)
{
if(strcmp(direntp->d_name,name)==0)
{
flag=1;
break;
}
else flag=0;
}
closedir(dirp);
if(flag)
{
strcat(pathname,name);
strcpy(full_pathname,pathname);
return 1;
}
else return 0;
}
else
{
return 0;
}
}