/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1988 AT&T */
/*        All Rights Reserved   */

/*
 * Search the specified path for a file with the specified
 * mode and type.  Return a pointer to the path.  If the
 * file isn't found, return NULL.
 */

#ifdef _REENTRANT
#include <thread.h>
#include <pthread.h>
#endif /* _REENTRANT */
#include <sys/types.h>
#include <libgen.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>

/*
 * Mode bit definitions -- see mknod(2)
 * Names of flags duplicate those of test(1)
 */


/* File type: 0170000 */
#define FFLAG   S_IFREG         /* normal file - also type 0 */
#define BFLAG   S_IFBLK         /* block special */
#define CFLAG   S_IFCHR         /* character special */
#define DFLAG   S_IFDIR         /* directory */
#define PFLAG   S_IFIFO         /* fifo */

#define UFLAG   S_ISUID         /* setuid */
#define GFLAG   S_ISGID         /* setgid */
#define KFLAG   S_ISVTX         /* sticky bit */

/*
 * Perms: 0700 user, 070 group, 07 other
 * Note that pathfind uses access(2), so no need to hassle
 * with shifts and such
 */
#define RFLAG   04              /* read */
#define WFLAG   02              /* write */
#define XFLAG   01              /* execute */

static int fullck(char *, mode_t, int);

#ifdef _REENTRANT
static char *
_get_cpath(thread_key_t *keyp)
{
        char *str;

        if (thr_keycreate_once(keyp, free) != 0)
                return (NULL);
        str = pthread_getspecific(*keyp);
        if (str == NULL) {
                str = calloc(PATH_MAX, sizeof (char));
                if (thr_setspecific(*keyp, str) != 0) {
                        if (str)
                                (void) free(str);
                        str = NULL;
                }
        }
        return (str);
}
#endif /* _REENTRANT */

char *
pathfind(const char *path, const char *name, const char *mode)
{
#ifdef _REENTRANT
        static thread_key_t key = THR_ONCE_KEY;
        char *cpath = _get_cpath(&key);
#else /* _REENTRANT */
        static char cpath[PATH_MAX];
#endif /* _REENTRANT */
        char *cp;
        mode_t imode;
        int nzflag;

        /* Build imode */
        imode = 0; nzflag = 0;
        if (mode == ((char *)0))
                mode = "";
        for (cp = (char *)mode; *cp; cp++) {
                switch (*cp) {
                case 'r':
                        imode |= RFLAG;
                        break;
                case 'w':
                        imode |= WFLAG;
                        break;
                case 'x':
                        imode |= XFLAG;
                        break;
                case 'b':
                        imode |= BFLAG;
                        break;
                case 'c':
                        imode |= CFLAG;
                        break;
                case 'd':
                        imode |= DFLAG;
                        break;
                case 'f':
                        imode |= FFLAG;
                        break;
                case 'p':
                        imode |= PFLAG;
                        break;
                case 'u':
                        imode |= UFLAG;
                        break;
                case 'g':
                        imode |= GFLAG;
                        break;
                case 'k':
                        imode |= KFLAG;
                        break;
                case 's':
                        nzflag = 1;
                        break;
                default:
                        return ((char *)0);
                }
        }

        if (name[0] == '/' || path == ((char *)0) || *path == '\0')
                path = ":";
        while (*path) {
                for (cp = cpath; (/* const */ char *) cp <
                    &cpath[PATH_MAX] && (*cp = *path); cp++) {
                        path++;
                        if (*cp == ':')
                                break;
                }
                if ((/* const */ char *) cp + strlen(name) + 2 >=
                    &cpath[PATH_MAX])
                        continue;
                if (cp != cpath)
                        *cp++ = '/';
                *cp = '\0';
                (void) strcat(cp, name);
                if (access(cpath, imode&07) == 0 &&
                    fullck(cpath, imode, nzflag))
                        return (cpath);
        }

        return ((char *)0);
}

static int
fullck(char *name, mode_t mode, int nzflag)
{
        struct stat64 sbuf;
        int xor;

        if ((mode & 0177000) == 0 && nzflag == 0) /* no special info wanted */
                return (1);
        if (stat64(name, &sbuf) == -1)
                return (0);
        xor = (sbuf.st_mode ^ mode) & 077000;   /* see mknod(2) */
        if ((mode & 0170000) == 0)
                xor &= ~070000;
        if ((mode & 07000) == 0)
                xor &= ~07000;
        if (xor)
                return (0);
        if (nzflag && sbuf.st_size == 0)
                return (0);
        return (1);
}