Tiny example program extracted from xconsole

ptsname-bug.c (text/plain), 942 bytes, created by Ferris McCormick (RETIRED) on 2006-03-20 12:55:35 UTC

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define _SZ 1024
static const char * PTC = "/dev/ptmx";
static int pty;
static char *ptc;
static char BUF[_SZ];
int
main(int argc, char* argv[]) {
  int i;
  for (i=0; i < _SZ; ++i) BUF[i]= (char)NULL;
  pty = open(PTC,O_RDONLY);
  if(pty < 0) {
    fprintf(stderr,"Can't open %s read-only\n", PTC);
    return (-1);
  } else {
    fprintf(stderr, "%s is open with descr = %d\n", PTC, pty);
  }
  /*  ptc = ptsname(pty);
   *  */
#ifdef SEG_FAULT
  ptc = ptsname(pty);
  if(ptc == NULL) {
#else
  ptc = ptsname_r(pty, BUF, _SZ);
  if(ptc != NULL) {
#endif
    fprintf(stderr, "Can't get name for %s(%d)\n", PTC, pty);
    return (-1);
  }
  fprintf(stderr, "fd %d gets pseudo-terminal pointer %x\n", pty, ptc);
#ifdef SEG_FAULT
  strcpy(BUF, ptc);
#endif
  fprintf(stderr,"Pseudo-terminal is %s\n", BUF);
  return 0;
}