non-root to umount /mnt/cdrom ?

Change the entry in fstab to include "owner". Something like:

/dev/cdrom              /cdrom                  iso9660 noauto,owner,ro 0 0

Give the user permissions to unmount the cdrom

Add option 'user' to /dev/cdrom's entry in /etc/fstab (man fstab tells everything).

Sorry,
I probably wasn't explicit enough. What I maent was, what is the best way to let a specific user do this, not all users.
thanks,

Adjusted points from 50 to 100

For that, you need something that runs the mount/unmount commands as root only for that user. You can do it with a suid script, but I prefer to use a small executable (as it's a bit more secure). I've got one that could be modified slightly to do it if you are interested.

I don't know much yet about suid. I know that there are security concerns w/ such scripts, but don't really know much about why. I'm not afraid of compiling a little code, if it is something a beginning programmer could understand. The truth is, on my home machine I am the only user, so modifying /etc/fstab would be acceptable, but what I'd like to do is learn the best way to handle this, in preperation of someday administering a system w/ multiple users.

I'll take your advise as to the best way to proceed.
thanks,

Well, shucky darn. Either I didn't manage to get my comment containing the code posted or it got lost... One more time... If you have trouble getting the code out of the comment and into a file, send me an email and I'll mail it to you (jlevie@bellsouth.net)

---begin cdutil.c---
/*
 * NAME
 *              cdutil - User level CD mount/umount
 *
 * SYNOPSIS
 *              cdutil mount | umount
 *
 * DESCRIPTION
 *              Allows those users listed in the "names" array access to "mount/umount"
 *              with root privs. You can include one or more users as desired as long as "NULL"
 *              terminates the array. You certainly will need to edit the "names" array to
 *              suit local use.
 *
 *              This utility is safe if installed properly. The executable should be placed in
 *              the user's PATH (/usr/bin comes to mind), owned by root, group root or bin,
 *              suid to root, and executable only by group & other. This can be easily done
 *              with:
 *
 *              root> cc -o cdutil cdutil.c
 *              root> cp cdutil /usr/bin
 *              root> chown root:root /usr/bin/cdutil
 *              root> chmod 6511 /usr/bin/cdutil
 *
 * AUTHOR; Jim Levie
 */

#include <stdio.h>
#include <pwd.h>

struct passwd *getpwuid();
extern char **environ;

char *names[] =
{ "first-user", "second-user", NULL};

char *mount[] = {"/bin/mount", "/mnt/cdrom", '\0'};
char *umount[] = {"/bin/umount", "/mnt/cdrom", '\0'};

char **cmd;

main(argc, argv)
int argc;
char **argv;
{
  char user[9];
  register int okay = 0, i;

  if(argc != 2)
  {
    puts("Usage: cdutil mount | umount\n");
    exit(1);
  }

  /*
     * Get and check the users name against our builtin names.
     */
  strcpy(user, getpwuid(getuid())->pw_name);
  for(i = 0; names[i]; i++)
  {
    if(!strcmp(user, names[i]))
    {
      okay = 1;
      break;
    }
  }  
  if(okay)
  {
    if(!strcmp(argv[1], "mount"))
    {
      cmd = mount;
    }
    else if(!strcmp(argv[1], "umount"))
    {  
      cmd = umount;      
    }
    else
    {
      puts("Usage: cdutil [mount | umount]\n");
      exit(1);
    }
    setuid(0);
    execvp(*cmd, cmd);
    puts("\nCan't execute.\n");
  }
  else
  {
    puts("Not by the hair of my chinny chin chin!\n");
  }
}
---end cdutil.c---