/* startchild
  name: procedure name (either in search path or full path specified)
  cin: file which will be child's stdin
  cout: file which will be child's stdout

  14 Mar 97.  Write in 1 printf instead of 2 (got first line but not
	2nd-hope this helps & doesn't eliminate both instead!)
	      Exit w/errno instead of 1 if errno non-zero.  WJS
   3 Jun 96.  Change error string so defgb can recognize it as error.  WJS
  30 May 96.  Mod to child process behavior after failed exec.  WJS
	1) print error info to stdout instead of stderr and
	flush it, thus feeding message to parent
	2) _exit()
*/

#include <errno.h>
#include <stdio.h>
#include <string.h>
#if SOL || HP
#include <sys/time.h>
#include <sys/resource.h>
#endif

startchild(name,cin,cout)
char *name;
FILE **cin, **cout;
{
static int pipeto[2],pipefrom[2];
int i,numfds,childpid;
char *args[20];
#if SOL || HP
  struct rlimit rlp;
#endif

if (pipe(pipeto) || pipe(pipefrom) <0) 
  {
  perror("no pipes");
  exit(1);
  }

switch(childpid = fork())
  {
  case -1:
    perror("bad fork");
    exit(1);
  case 0:
/*
    fprintf(stderr,"got here after fork\n");
    fprintf(stderr,"%s\n",name);
*/
    dup2(pipeto[0],0);
    dup2(pipefrom[1],1); 
#if SOL || HP
      getrlimit(RLIMIT_NOFILE,&rlp);
      numfds=rlp.rlim_cur;
#else
      numfds = getdtablesize();
#endif
    for (i=3; i<numfds; i++)
      close(i);
    i=0;
    args[i++]=strtok(name," ");
    while(args[i]=strtok(NULL," "))i++;
    i=0;
/*
    while(args[i])fprintf(stderr,"arg %d = %s\n",i,args[i++]);
*/
    execvp(args[0],args);
/*    Error if we return from execvp					   */
/*    "*** Error" is magic string causing defgb to interpret line as error */
/*    message.  Defined as ERR_PREFIX in defgb.h, but not sure I should    */
/*    include that in what is possibly a library subroutine		   */
    printf("*** Error: startchild exec error in child process\n%s: %s\n",
      args[0],strerror(errno));
    fflush(NULL);
    if (errno == 0) errno = 1;
    _exit(errno);
  default:
    close(pipeto[0]);
    close(pipefrom[1]); 
/*    ptoch = pipeto[1];*/
/*    pfrch = pipefrom[0];*/
    *cin = fdopen(pipeto[1],"w");
    *cout = fdopen(pipefrom[0],"r");
    setbuf(*cin,NULL);
/*    setbuf(frch,NULL);*/
    break;
  }
}