🚀 go-pugleaf

In article <7466@ucsbcsl.ucsb.edu> doug@foxtrot.ccmrc.ucsb.edu (Douglas Scott) writes:
>I am writing some C code which needs to check to see if the user is logged
>onto the console (i.e., any tty, as long as the user is sitting at the
>console).
>
>What is the easiest way to check to see if this is true?

This is the eisiest way that I have found to do it.  You should be
able to modify it to suit your needs as follows.

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#include <stdio.h>
#include <utmp.h>
 
#define		ATCONSOLE	1
#define		FAILED		2
#define		NOTATCONSOLE	3
 
#define		MAXNAME		12
 
find_user(char *name)
{
  struct utmp ubuf;
  FILE *fd;
 
  if ((fd = fopen("/etc/utmp", "r")) == NULL) {
    perror("Can't open /etc/utmp");
    return (FAILED);
  }
  while (fread((char *) &ubuf, sizeof ubuf, 1, fd) == 1) {
    if(strncmp(ubuf.ut_name, name, sizeof(ubuf.ut_name)) == 0 &&
       strcmp(ubuf.ut_line, "console") == 0)
      return ATCONSOLE;
  }
  return NOTATCONSOLE;
}
 
main() {
  char *loginName;
  loginName = (char *)malloc(sizeof(char) * MAXNAME);
  scanf("%s", loginName);
  if(find_user(loginName) == ATCONSOLE)
    printf("%s is at the console.\n", loginName);
  else
    printf("%s is not at the console.\n");
}

-- 

		-Scott Violet (xepo@csd4.csd.uwm.edu)