- Every non-const pointer converts automatically to void *. - Every pointer converts automatically to void *. - void * converts to any other pointer. - const void * converts to any other const pointer. - Integer variables convert to each other. I changed the declaration of a few variables in order to allow removing a cast. However, I didn't attempt to edit casts inside comparisons, since they are very delicate. I also kept casts in variadic functions, since they are necessary, and in allocation functions, because I have other plans for them. I also changed a few casts to int that are better as ptrdiff_t. This change has triggered some warnings about const correctness issues, which have also been fixed in this patch (see for example src/login.c). Signed-off-by: Alejandro Colomar <alx@kernel.org>
		
			
				
	
	
		
			109 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			109 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * SPDX-FileCopyrightText: 1991       , Julianne Frances Haugh
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 * SPDX-FileCopyrightText: 1991       , Chip Rosenthal
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 * SPDX-FileCopyrightText: 1996 - 1998, Marek Michałkiewicz
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 * SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
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 * SPDX-FileCopyrightText: 2007 - 2010, Nicolas François
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 *
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 * SPDX-License-Identifier: BSD-3-Clause
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 */
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#include <config.h>
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#include "defines.h"
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#include <stdio.h>
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#include "getdef.h"
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#include "prototypes.h"
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#ident "$Id$"
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/*
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 * This is now rather generic function which decides if "tty" is listed
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 * under "cfgin" in config (directly or indirectly). Fallback to default if
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 * something is bad.
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 */
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static bool is_listed (const char *cfgin, const char *tty, bool def)
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{
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	FILE *fp;
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	char buf[1024], *s;
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	const char *cons;
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	/*
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	 * If the CONSOLE configuration definition isn't given,
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	 * fallback to default.
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	 */
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	cons = getdef_str (cfgin);
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	if (NULL == cons) {
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		return def;
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	}
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	/*
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	 * If this isn't a filename, then it is a ":" delimited list of
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	 * console devices upon which root logins are allowed.
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	 */
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	if (*cons != '/') {
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		char *pbuf;
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		strlcpy (buf, cons, sizeof (buf));
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		pbuf = &buf[0];
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		while ((s = strtok (pbuf, ":")) != NULL) {
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			if (strcmp (s, tty) == 0) {
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				return true;
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			}
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			pbuf = NULL;
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		}
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		return false;
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	}
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	/*
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	 * If we can't open the console list, then call everything a
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	 * console - otherwise root will never be allowed to login.
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	 */
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	fp = fopen (cons, "r");
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	if (NULL == fp) {
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		return def;
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	}
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	/*
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	 * See if this tty is listed in the console file.
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	 */
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	while (fgets (buf, sizeof (buf), fp) != NULL) {
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		/* Remove optional trailing '\n'. */
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		buf[strcspn (buf, "\n")] = '\0';
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		if (strcmp (buf, tty) == 0) {
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			(void) fclose (fp);
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			return true;
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		}
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	}
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	/*
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	 * This tty isn't a console.
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	 */
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	(void) fclose (fp);
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	return false;
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}
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/*
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 * console - return 1 if the "tty" is a console device, else 0.
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 *
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 * Note - we need to take extreme care here to avoid locking out root logins
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 * if something goes awry.  That's why we do things like call everything a
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 * console if the consoles file can't be opened.  Because of this, we must
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 * warn the user to protect against the remove of the consoles file since
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 * that would allow an unauthorized root login.
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 */
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bool console (const char *tty)
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{
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	if (strncmp (tty, "/dev/", 5) == 0) {
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		tty += 5;
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	}
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	return is_listed ("CONSOLE", tty, true);
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}
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