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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 
getmntent(FILE * fp)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 
getmntent_r(FILE * fp,struct mntent * e,char * buf,int buf_len)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) != nullptr) {
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 nullptr;
64 }
65 
setmntent(const char * path,const char * mode)66 FILE* setmntent(const char* path, const char* mode) {
67   return fopen(path, mode);
68 }
69 
endmntent(FILE * fp)70 int endmntent(FILE* fp) {
71   if (fp != nullptr) {
72     fclose(fp);
73   }
74   return 1;
75 }
76 
hasmntopt(const struct mntent * mnt,const char * opt)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