shadow/libmisc/console.c

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/*
* Copyright 1991, Julianne Frances Haugh and Chip Rosenthal
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Julianne F. Haugh nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <config.h>
#include "defines.h"
#include <stdio.h>
#include "getdef.h"
#ident "$Id$"
/* local function prototypes */
static int is_listed (const char *cfgin, const char *tty, int def);
/*
* This is now rather generic function which decides if "tty" is listed
* under "cfgin" in config (directly or indirectly). Fallback to default if
* something is bad.
*/
static int is_listed (const char *cfgin, const char *tty, int def)
{
FILE *fp;
char buf[200], *cons, *s;
/*
* If the CONSOLE configuration definition isn't given,
* fallback to default.
*/
if ((cons = getdef_str (cfgin)) == NULL)
return def;
/*
* If this isn't a filename, then it is a ":" delimited list of
* console devices upon which root logins are allowed.
*/
if (*cons != '/') {
cons = strcpy (buf, cons);
while ((s = strtok (cons, ":")) != NULL) {
if (strcmp (s, tty) == 0)
return 1;
cons = NULL;
}
return 0;
}
/*
* If we can't open the console list, then call everything a
* console - otherwise root will never be allowed to login.
*/
if ((fp = fopen (cons, "r")) == NULL)
return def;
/*
* See if this tty is listed in the console file.
*/
while (fgets (buf, sizeof (buf), fp) != NULL) {
buf[strlen (buf) - 1] = '\0';
if (strcmp (buf, tty) == 0) {
(void) fclose (fp);
return 1;
}
}
/*
* This tty isn't a console.
*/
(void) fclose (fp);
return 0;
}
/*
* console - return 1 if the "tty" is a console device, else 0.
*
* Note - we need to take extreme care here to avoid locking out root logins
* if something goes awry. That's why we do things like call everything a
* console if the consoles file can't be opened. Because of this, we must
* warn the user to protect against the remove of the consoles file since
* that would allow an unauthorized root login.
*/
int console (const char *tty)
{
return is_listed ("CONSOLE", tty, 1);
}