dirname.c

/*      $OpenBSD: dirname.c,v 1.10 2003/06/17 21:56:23 millert Exp $        */

/*
 * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#ifndef lint
static char rcsid[] = "$OpenBSD: dirname.c,v 1.10 2003/06/17 21:56:23 millert Exp $";
#endif /* not lint */

#include <string.h>
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#elif !defined(MAXPATHLEN)
#define MAXPATHLEN 1024
#endif

char *
dirname(const char *path)
{
	static char bname[MAXPATHLEN];
	register const char *endp;

	/* Empty or NULL string gets treated as "." */
	if (path == NULL || *path == '\0') {
		(void)strcpy(bname, ".");
		return(bname);
	}

	/* Strip trailing slashes */
	endp = path + strlen(path) - 1;
	while (endp > path && *endp == '/')
		endp--;

	/* Find the start of the dir */
	while (endp > path && *endp != '/')
		endp--;

	/* Either the dir is "/" or there are no slashes */
	if (endp == path) {
		(void)strcpy(bname, *endp == '/' ? "/" : ".");
		return(bname);
	} else {
		do {
			endp--;
		} while (endp > path && *endp == '/');
	}

	if (endp - path + 2 > sizeof(bname)) {
		return(NULL);
	}
	(void)strncpy(bname, path, endp - path + 1);
	bname[endp - path + 1] = '\0';
	return(bname);
}