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Mike
05-06-2010, 08:04 PM
Bottom of the 9th. Bases loaded.

a#include "smallsh.h" /*include file for example*/

/*program buffers and work pointers*/
static char inpbuf[MAXBUF], tokbuf[2*MAXBUF],
*ptr = inpbuf, *tok = tokbuf;

userin(p) /*print prompt and read a line*/
char *p;
{

int c, count;

/*initialization for later routines*/
ptr = inpbuf;
tok = tokbuf;

/*display prompt*/
printf("%s ",p);

for(count = 0;;)
{
if((c = getchar()) == EOF)
return(EOF);

if(count<MAXBUF)
inpbuf[count++] = c;

if(c == '\n' && count <MAXBUF)
{
inpbuf[count] = '\0';
return(count);
}

/*if line too long restart*/
if(c == '\n')
{
printf("smallsh:input line too long\n");
count = 0;
printf("%s",p);
}
}
}

gettok(outptr) /*get token and place into tokbuf*/
char **outptr;
{
int type;

*outptr = tok;

/*strip white space*/
for(;*ptr == ' ' || *ptr == '\t'; ptr++)
;

*tok++ = *ptr;

switch(*ptr++)
{
case '\n':
type = EOL; break;
case '&':
type = AMPERSAND; break;
case ';':
type = SEMICOLON; break;
case '#':
type = POUND; break;
default:
type = ARG;
while(inarg(*ptr))
*tok++ = *ptr++;
}

*tok++ = '\0';
return(type);
}

static char special[]=
{' ', '\t', '&', ':', '\n', '\0'};

inarg(c) /*are we in an ordinary argument*/
char c;
{
char *wrk;

for(wrk = special;*wrk != '\0';wrk++)
if(c == *wrk)
return(0);

return(1);
}

#include "smallsh.h"

procline() /*process input line*/
{
char *arg[MAXARG+1]; /*pointer array for runcommand*/
int toktype; /*type of token in command*/
int narg; /*number of arguments so far*/
int type; /*FOREGROUND or BACKGROUND*/

for(narg = 0;;)
{
/*loop FOREVER*/

/*take action according to token type*/

switch(toktype = gettok(&arg[narg]))
{
case ARG:

if(narg<MAXARG)
narg++;
break;

case EOL:
case SEMICOLON:
case AMPERSAND:
case POUND:

type = (toktype == AMPERSAND) ?
BACKGROUND : FOREGROUND;

if(narg!=0)
{
arg[narg] = NULL;
runcommand(arg, type);
}

if((toktype == EOL)||(toktype=POUND))
return;

narg = 0;
break;
}
}
}


#include "smallsh.h"

/*execute a command with optional wait*/
runcommand(cline,where)
char **cline;
int where;
{
int pid, exitstat, ret;

if((pid = fork()) <0)
{
perror("smallsh");
return(-1);
}

if(pid == 0)
{
/*child*/
execvp(*cline, cline);
perror(*cline);
exit(127);
}

/*code for parent*/
/*if background process print pid and exit*/

if(where == BACKGROUND)
{
printf("[Process id %d]\n", pid);
return(0);
}

/*wait until process pid exists*/

while( (ret=wait(&exitstat)) != pid && ret != -1)
;

return(ret == -1 ? -1 : exitstat);
}

#include "smallsh.h"

char *prompt = "Command>"; /*prompt*/

main()
{
while(userin(prompt) != EOF)
procline();
}



How do I add a custom function to this? Note: DEADLINE LOOMING.

Vicious88
05-07-2010, 12:00 AM
Regrettably, I do not know.