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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 "bionic/pthread_internal.h"
     38 
     39 static 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 // Since this is a non-standard symbol, it might be hijacked by a basename_r in the executable.
     92 __LIBC32_LEGACY_PUBLIC__ int basename_r(const char* path, char* buffer, size_t buffer_size) {
     93   return __basename_r(path, buffer, buffer_size);
     94 }
     95 
     96 static int __dirname_r(const char* path, char* buffer, size_t buffer_size) {
     97   const char* endp = NULL;
     98   int len;
     99   int result;
    100 
    101   // Empty or NULL string gets treated as ".".
    102   if (path == NULL || *path == '\0') {
    103     path = ".";
    104     len = 1;
    105     goto Exit;
    106   }
    107 
    108   // Strip trailing slashes.
    109   endp = path + strlen(path) - 1;
    110   while (endp > path && *endp == '/') {
    111     endp--;
    112   }
    113 
    114   // Find the start of the dir.
    115   while (endp > path && *endp != '/') {
    116     endp--;
    117   }
    118 
    119   // Either the dir is "/" or there are no slashes.
    120   if (endp == path) {
    121     path = (*endp == '/') ? "/" : ".";
    122     len = 1;
    123     goto Exit;
    124   }
    125 
    126   do {
    127     endp--;
    128   } while (endp > path && *endp == '/');
    129 
    130   len = endp - path + 1;
    131 
    132  Exit:
    133   result = len;
    134   if (len + 1 > MAXPATHLEN) {
    135     errno = ENAMETOOLONG;
    136     return -1;
    137   }
    138   if (buffer == NULL) {
    139     return result;
    140   }
    141 
    142   if (len > static_cast<int>(buffer_size) - 1) {
    143     len = buffer_size - 1;
    144     result = -1;
    145     errno = ERANGE;
    146   }
    147 
    148   if (len >= 0) {
    149     memcpy(buffer, path, len);
    150     buffer[len] = 0;
    151   }
    152   return result;
    153 }
    154 
    155 // Since this is a non-standard symbol, it might be hijacked by a basename_r in the executable.
    156 __LIBC32_LEGACY_PUBLIC__ int dirname_r(const char* path, char* buffer, size_t buffer_size) {
    157   return __dirname_r(path, buffer, buffer_size);
    158 }
    159 
    160 char* basename(const char* path) {
    161   char* buf = __get_bionic_tls().basename_buf;
    162   int rc = __basename_r(path, buf, sizeof(__get_bionic_tls().basename_buf));
    163   return (rc < 0) ? NULL : buf;
    164 }
    165 
    166 char* dirname(const char* path) {
    167   char* buf = __get_bionic_tls().dirname_buf;
    168   int rc = __dirname_r(path, buf, sizeof(__get_bionic_tls().dirname_buf));
    169   return (rc < 0) ? NULL : buf;
    170 }
    171