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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 #include <libgen.h>
     29 #include <errno.h>
     30 #include <string.h>
     31 #include <sys/param.h>
     32 
     33 int
     34 dirname_r(const char*  path, char*  buffer, size_t  bufflen)
     35 {
     36     const char *endp;
     37     int         result, len;
     38 
     39     /* Empty or NULL string gets treated as "." */
     40     if (path == NULL || *path == '\0') {
     41         path = ".";
     42         len  = 1;
     43         goto Exit;
     44     }
     45 
     46     /* Strip trailing slashes */
     47     endp = path + strlen(path) - 1;
     48     while (endp > path && *endp == '/')
     49         endp--;
     50 
     51     /* Find the start of the dir */
     52     while (endp > path && *endp != '/')
     53         endp--;
     54 
     55     /* Either the dir is "/" or there are no slashes */
     56     if (endp == path) {
     57         path = (*endp == '/') ? "/" : ".";
     58         len  = 1;
     59         goto Exit;
     60     }
     61 
     62     do {
     63         endp--;
     64     } while (endp > path && *endp == '/');
     65 
     66     len = endp - path +1;
     67 
     68 Exit:
     69     result = len;
     70     if (len+1 > MAXPATHLEN) {
     71         errno = ENAMETOOLONG;
     72         return -1;
     73     }
     74     if (buffer == NULL)
     75         return result;
     76 
     77     if (len > (int)bufflen-1) {
     78         len    = (int)bufflen-1;
     79         result = -1;
     80         errno  = ERANGE;
     81     }
     82 
     83     if (len >= 0) {
     84         memcpy( buffer, path, len );
     85         buffer[len] = 0;
     86     }
     87     return result;
     88 }
     89