shell programming problem

[jorntk]

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <string.h>

/*limit the lenght of input to 256 character and number
of argument to 10*/
#define MAX 256
#define CMAX 10
char logout[]= "logout";

int spawn(char* program, char** arg_list)
{
pid_t child_pid;
if(!strcmp(program,logout))
{
exit(0);
}
if ((child_pid=fork())==0)
{
execvp(program,arg_list);
perror("execvp");
exit(1);
}
}

int main()
{
char input[MAX];
char *p;
char *arg_list[CMAX+1];
int i;
while(1)
{
printf("Shell> ");
if (fgets(input,sizeof input, stdin)!=NULL)
{
if(strchr(input,'\n'))
*strchr(input,'\n')=0;
else
{
while (!strchr(input,'\n'))
fgets(input, sizeof input,stdin);
exit(1);
}
}
p=strtok(input," ");
for(i=0;i<CMAX;++i)
{
arg_list[i]=p;
p=strtok(NULL," ");
}
arg_list[i]=0;

spawn(arg_list[0], arg_list);
}
return 0;
}

the above program can accept commnand from user and execute it, i need
advice on how to expand its function to include pipe function. other
thing is where should i place code to exit when logout is enter, i
have try checking in spawn process it works but the program will
return segmentation error when click enter with not other command.
thanks in advance.

[Artie Gold]

jo****@yahoo.com wrote:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
Use of this header (which is not a standard C header) makes me
suspect that your question is off topic here and that should take
your question to:

news:comp.unix.programmer
#include <sys/types.h>
Hmmm, I'm starting to think my suspicion is correct.
#include <string.h>

/*limit the lenght of input to 256 character and number
of argument to 10*/
#define MAX 256
#define CMAX 10
char logout[]= "logout";

int spawn(char* program, char** arg_list)
{
pid_t child_pid;
if(!strcmp(program,logout))
{
exit(0);
}
if ((child_pid=fork())==0)
{
execvp(program,arg_list);
perror("execvp");
exit(1);
}
}

int main()
{
char input[MAX];
char *p;
char *arg_list[CMAX+1];
int i;
while(1)
{
printf("Shell> ");
if (fgets(input,sizeof input, stdin)!=NULL)
{
if(strchr(input,'\n'))
*strchr(input,'\n')=0;
else
{
while (!strchr(input,'\n'))
fgets(input, sizeof input,stdin);
exit(1);
}
}
p=strtok(input," ");
for(i=0;i<CMAX;++i)
{
arg_list[i]=p;
p=strtok(NULL," ");
}
arg_list[i]=0;

spawn(arg_list[0], arg_list);
}
return 0;
}

the above program can accept commnand from user and execute it, i need
advice on how to expand its function to include pipe function. other
thing is where should i place code to exit when logout is enter, i
have try checking in spawn process it works but the program will
return segmentation error when click enter with not other command.
thanks in advance.

Yup.
Off topic here.

news:comp.unix.programmer is the place for you to ask.

--ag
--
Artie Gold -- Austin, Texas