linux下使用系统调用模拟SHELL

王朝system·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

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][n]=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;

}

}

 
 
 
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