lib/search_path.c

/* $Header: /cvsroot/ltp/ltp/lib/search_path.c,v 1.4 2009/07/20 10:59:32 vapier Exp $ */

/*
 * Copyright (c) 2000 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/NoticeExplan/
 */

/**********************************************************
 *
 *    UNICOS Feature Test and Evaluation - Cray Research, Inc.
 *
 *    FUNCTION NAME 	: search_path
 *
 *    FUNCTION TITLE	: search PATH locations for desired filename
 *
 *    SYNOPSIS:
 *	int search_path(cmd, res_path, access_mode, fullpath)
 *	char *cmd;
 *	char *res_path;
 *	int access_mode;
 *	int fullpath;
 *
 *    AUTHOR		: Richard Logan
 *
 *    INITIAL RELEASE	: UNICOS 7.0
 *
 *    DESCRIPTION
 *	Search_path will walk through PATH and attempt to find "cmd".  If cmd is
 *	a full or relative path, it is checked but PATH locations are not scanned.
 *	search_path will put the resulting path in res_path.  It is assumed
 *	that res_path points to a string that is at least PATH_MAX
 *	(or MAXPATHLEN on the suns) in size.  Access_mode is just as is
 *	says, the mode to be used on access to determine if cmd can be found.
 *	If fullpath is set, res_path will contain the full path to cmd.
 *	If it is not set, res_path may or may not contain the full path to cmd.
 *	If fullpath is not set, the path in PATH prepended to cmd is used,
 *	which could be a relative path.  If fullpath is set, the current
 *	directory is prepended to path/cmd before access is called.
 *	If cmd is found, search_path will return 0.  If cmd cannot be
 *	found, 1 is returned.  If an error has occurred, -1 is returned
 *	and an error mesg is placed in res_path.
 *	If the length of path/cmd is larger then PATH_MAX, then that path
 *	location is skipped.
 *
 *#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#*#**/

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/param.h>
#include <sys/stat.h>

struct stat stbuf;

#ifndef AS_CMD
#define AS_CMD	0
#endif

/*
 * Make sure PATH_MAX is defined.  Define it to MAXPATHLEN, if set. Otherwise
 * set it to 1024.
 */
#ifndef PATH_MAX
#ifndef MAXPATHLEN
#define PATH_MAX     1024
#else /* MAXPATHLEN */
#define PATH_MAX     MAXPATHLEN
#endif /* MAXPATHLEN */
#endif /* PATH_MAX */

#if AS_CMD
main(argc, argv)
int argc;
char **argv;
{
	char path[PATH_MAX];
	int ind;

	if (argc <= 1) {
		printf("missing argument\n");
		exit(1);
	}

	for (ind = 1; ind < argc; ind++) {
		if (search_path(argv[ind], path, F_OK, 0) < 0) {
			printf("ERROR: %s\n", path);
		} else {
			printf("path of %s is %s\n", argv[ind], path);
		}
	}

}

#endif

/*
 */
int search_path(cmd, res_path, access_mode, fullpath)
char *cmd;			/* The requested filename */
char *res_path;			/* The resulting path or error mesg */
int access_mode;		/* the mode used by access(2) */
int fullpath;			/* if set, cwd will be prepended to all non-full paths */
{
	char *cp;		/* used to scan PATH for directories */
	int ret;		/* return value from access */
	char *pathenv;
	char tmppath[PATH_MAX];
	char curpath[PATH_MAX];
	char *path;
	int lastpath;
	int toolong = 0;

#if DEBUG
	printf("search_path: cmd = %s, access_mode = %d, fullpath = %d\n", cmd,
	       access_mode, fullpath);
#endif

	/*
	 * full or relative path was given
	 */
	if ((cmd[0] == '/') || ((cp = strchr(cmd, '/')) != NULL)) {
		if (access(cmd, access_mode) == 0) {

			if (cmd[0] != '/') {	/* relative path */
				if (getcwd(curpath, PATH_MAX) == NULL) {
					strcpy(res_path, curpath);
					return -1;
				}
				if ((strlen(curpath) + strlen(cmd) + 1) >
				    (size_t) PATH_MAX) {
					sprintf(res_path,
						"cmd (as relative path) and cwd is longer than %d",
						PATH_MAX);
					return -1;
				}
				sprintf(res_path, "%s/%s", curpath, cmd);
			} else
				strcpy(res_path, cmd);
			return 0;
		} else {
			sprintf(res_path, "file %s not found", cmd);
			return -1;
		}
	}

	/* get the PATH variable */
	if ((pathenv = getenv("PATH")) == NULL) {
		/* no path to scan, return */
		sprintf(res_path, "Unable to get PATH env. variable");
		return -1;
	}

	/*
	 * walk through each path in PATH.
	 * Each path in PATH is placed in tmppath.
	 * pathenv cannot be modified since it will affect PATH.
	 * If a signal came in while we have modified the PATH
	 * memory, we could create a problem for the caller.
	 */

	curpath[0] = '\0';

	cp = pathenv;
	path = pathenv;
	lastpath = 0;
	for (;;) {

		if (lastpath)
			break;

		if (cp != pathenv)
			path = ++cp;	/* already set on first iteration */

		/* find end of current path */

		for (; ((*cp != ':') && (*cp != '\0')); cp++) ;

		/*
		 * copy path to tmppath so it can be NULL terminated
		 * and so we do not modify path memory.
		 */
		strncpy(tmppath, path, (cp - path));
		tmppath[cp - path] = '\0';
#if DEBUG
		printf("search_path: tmppath = %s\n", tmppath);
#endif

		if (*cp == '\0')
			lastpath = 1;	/* this is the last path entry */

		/* Check lengths so not to overflow res_path */
		if (strlen(tmppath) + strlen(cmd) + 2 > (size_t) PATH_MAX) {
			toolong++;
			continue;
		}

		sprintf(res_path, "%s/%s", tmppath, cmd);
#if DEBUG
		printf("search_path: res_path = '%s'\n", res_path);
#endif

		/* if the path is not full at this point, prepend the current
		 * path to get the full path.
		 * Note:  this could not be wise to do when under a protected
		 * directory.
		 */

		if (fullpath && res_path[0] != '/') {	/* not a full path */
			if (curpath[0] == '\0') {
				if (getcwd(curpath, PATH_MAX) == NULL) {
					strcpy(res_path, curpath);
					return -1;
				}
			}
			if ((strlen(curpath) + strlen(res_path) + 2) >
			    (size_t) PATH_MAX) {
				toolong++;
				continue;
			}
			sprintf(tmppath, "%s/%s", curpath, res_path);
			strcpy(res_path, tmppath);
#if DEBUG
			printf("search_path: full res_path= '%s'\n", res_path);
#endif

		}

		if ((ret = access(res_path, access_mode)) == 0) {
#if DEBUG
			printf("search_path: found res_path = %s\n", res_path);
#endif
			return 0;
		}
	}

	/* return failure */
	if (toolong)
		sprintf(res_path,
			"Unable to find file, %d path/file strings were too long",
			toolong);
	else
		strcpy(res_path, "Unable to find file");
	return 1;		/* not found */
}