Eric Allman's fixes to remove VAX and VMUNIX dependencies

[unix-history] / usr / src / usr.bin / mail / popen.c

#include <stdio.h>
#include <signal.h>
#include <errno.h>
#define tst(a,b)        (*mode == 'r'? (b) : (a))
#define RDR     0
#define WTR     1
static  int     popen_pid[20];
static  char    *sccsid = "@(#)popen.c  1.2.1.2 %G%";

# ifndef VMUNIX
# define vfork  fork
# endif VMUNIX

FILE *
popen(cmd,mode)
char    *cmd;
char    *mode;
{
       int p[2];
       register myside, hisside, pid;

       if(pipe(p) < 0)
               return NULL;
       myside = tst(p[WTR], p[RDR]);
       hisside = tst(p[RDR], p[WTR]);
       if((pid = vfork()) == 0) {
               /* myside and hisside reverse roles in child */
               close(myside);
               dup2(hisside, tst(0, 1));
               close(hisside);
               execl("/bin/csh", "sh", "-c", cmd, 0);
               _exit(1);
       }
       if(pid == -1)
               return NULL;
       popen_pid[myside] = pid;
       close(hisside);
       return(fdopen(myside, mode));
}

pclose(ptr)
FILE *ptr;
{
       register f, r;
       int status;
       extern int errno;

       f = fileno(ptr);
       fclose(ptr);
# ifdef VMUNIX
       sighold(SIGINT);
       sighold(SIGQUIT);
       sighold(SIGHUP);
# endif VMUNIX
       while((r = wait(&status)) != popen_pid[f] && r != -1 && errno != EINTR)
               ;
       if(r == -1)
               status = -1;
# ifdef VMUNIX
       sigrelse(SIGINT);
       sigrelse(SIGQUIT);
       sigrelse(SIGHUP);
# endif VMUNIX
       return(status);
}