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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 <mntent.h>
     30 #include <string.h>
     31 
     32 #include "bionic/pthread_internal.h"
     33 
     34 mntent* getmntent(FILE* fp) {
     35   auto& tls = __get_bionic_tls();
     36   return getmntent_r(fp, &tls.mntent_buf, tls.mntent_strings, sizeof(tls.mntent_strings));
     37 }
     38 
     39 mntent* getmntent_r(FILE* fp, struct mntent* e, char* buf, int buf_len) {
     40   memset(e, 0, sizeof(*e));
     41   while (fgets(buf, buf_len, fp) != NULL) {
     42     // Entries look like "proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0".
     43     // That is: mnt_fsname mnt_dir mnt_type mnt_opts 0 0.
     44     int fsname0, fsname1, dir0, dir1, type0, type1, opts0, opts1;
     45     if (sscanf(buf, " %n%*s%n %n%*s%n %n%*s%n %n%*s%n %d %d",
     46                &fsname0, &fsname1, &dir0, &dir1, &type0, &type1, &opts0, &opts1,
     47                &e->mnt_freq, &e->mnt_passno) == 2) {
     48       e->mnt_fsname = &buf[fsname0];
     49       buf[fsname1] = '\0';
     50 
     51       e->mnt_dir = &buf[dir0];
     52       buf[dir1] = '\0';
     53 
     54       e->mnt_type = &buf[type0];
     55       buf[type1] = '\0';
     56 
     57       e->mnt_opts = &buf[opts0];
     58       buf[opts1] = '\0';
     59 
     60       return e;
     61     }
     62   }
     63   return NULL;
     64 }
     65 
     66 FILE* setmntent(const char* path, const char* mode) {
     67   return fopen(path, mode);
     68 }
     69 
     70 int endmntent(FILE* fp) {
     71   if (fp != NULL) {
     72     fclose(fp);
     73   }
     74   return 1;
     75 }
     76 
     77 char* hasmntopt(const struct mntent* mnt, const char* opt) {
     78   char* token = mnt->mnt_opts;
     79   char* const end = mnt->mnt_opts + strlen(mnt->mnt_opts);
     80   const size_t optLen = strlen(opt);
     81 
     82   while (token) {
     83     char* const tokenEnd = token + optLen;
     84     if (tokenEnd > end) break;
     85 
     86     if (memcmp(token, opt, optLen) == 0 &&
     87         (*tokenEnd == '\0' || *tokenEnd == ',' || *tokenEnd == '=')) {
     88       return token;
     89     }
     90 
     91     token = strchr(token, ',');
     92     if (token) token++;
     93   }
     94 
     95   return nullptr;
     96 }
     97