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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 
     29 #include <libgen.h>
     30 
     31 #include <errno.h>
     32 #include <stdlib.h>
     33 #include <string.h>
     34 #include <sys/cdefs.h>
     35 #include <sys/param.h>
     36 
     37 #include "private/ThreadLocalBuffer.h"
     38 
     39 __LIBC64_HIDDEN__ int basename_r(const char* path, char* buffer, size_t buffer_size) {
     40   const char* startp = NULL;
     41   const char* endp = NULL;
     42   int len;
     43   int result;
     44 
     45   // Empty or NULL string gets treated as ".".
     46   if (path == NULL || *path == '\0') {
     47     startp = ".";
     48     len = 1;
     49     goto Exit;
     50   }
     51 
     52   // Strip trailing slashes.
     53   endp = path + strlen(path) - 1;
     54   while (endp > path && *endp == '/') {
     55     endp--;
     56   }
     57 
     58   // All slashes becomes "/".
     59   if (endp == path && *endp == '/') {
     60     startp = "/";
     61     len = 1;
     62     goto Exit;
     63   }
     64 
     65   // Find the start of the base.
     66   startp = endp;
     67   while (startp > path && *(startp - 1) != '/') {
     68     startp--;
     69   }
     70 
     71   len = endp - startp +1;
     72 
     73  Exit:
     74   result = len;
     75   if (buffer == NULL) {
     76     return result;
     77   }
     78   if (len > static_cast<int>(buffer_size) - 1) {
     79     len = buffer_size - 1;
     80     result = -1;
     81     errno = ERANGE;
     82   }
     83 
     84   if (len >= 0) {
     85     memcpy(buffer, startp, len);
     86     buffer[len] = 0;
     87   }
     88   return result;
     89 }
     90 
     91 __LIBC64_HIDDEN__ int dirname_r(const char* path, char* buffer, size_t buffer_size) {
     92   const char* endp = NULL;
     93   int len;
     94   int result;
     95 
     96   // Empty or NULL string gets treated as ".".
     97   if (path == NULL || *path == '\0') {
     98     path = ".";
     99     len = 1;
    100     goto Exit;
    101   }
    102 
    103   // Strip trailing slashes.
    104   endp = path + strlen(path) - 1;
    105   while (endp > path && *endp == '/') {
    106     endp--;
    107   }
    108 
    109   // Find the start of the dir.
    110   while (endp > path && *endp != '/') {
    111     endp--;
    112   }
    113 
    114   // Either the dir is "/" or there are no slashes.
    115   if (endp == path) {
    116     path = (*endp == '/') ? "/" : ".";
    117     len = 1;
    118     goto Exit;
    119   }
    120 
    121   do {
    122     endp--;
    123   } while (endp > path && *endp == '/');
    124 
    125   len = endp - path + 1;
    126 
    127  Exit:
    128   result = len;
    129   if (len + 1 > MAXPATHLEN) {
    130     errno = ENAMETOOLONG;
    131     return -1;
    132   }
    133   if (buffer == NULL) {
    134     return result;
    135   }
    136 
    137   if (len > static_cast<int>(buffer_size) - 1) {
    138     len = buffer_size - 1;
    139     result = -1;
    140     errno = ERANGE;
    141   }
    142 
    143   if (len >= 0) {
    144     memcpy(buffer, path, len);
    145     buffer[len] = 0;
    146   }
    147   return result;
    148 }
    149 
    150 GLOBAL_INIT_THREAD_LOCAL_BUFFER(basename);
    151 GLOBAL_INIT_THREAD_LOCAL_BUFFER(dirname);
    152 
    153 char* basename(const char* path) {
    154   LOCAL_INIT_THREAD_LOCAL_BUFFER(char*, basename, MAXPATHLEN);
    155   int rc = basename_r(path, basename_tls_buffer, basename_tls_buffer_size);
    156   return (rc < 0) ? NULL : basename_tls_buffer;
    157 }
    158 
    159 char* dirname(const char* path) {
    160   LOCAL_INIT_THREAD_LOCAL_BUFFER(char*, dirname, MAXPATHLEN);
    161   int rc = dirname_r(path, dirname_tls_buffer, dirname_tls_buffer_size);
    162   return (rc < 0) ? NULL : dirname_tls_buffer;
    163 }
    164