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250b1eec | 1 | /* Utilities for reading/writing fstab, mtab, etc. |
5f76b90f | 2 | * Copyright (C) 1995-2000, 2001, 2002, 2003, 2006 |
3 | * Free Software Foundation, Inc. | |
4 | * This file is part of the GNU C Library. | |
5 | * | |
6 | * The GNU C Library is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
10 | * | |
11 | * The GNU C Library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
250b1eec SG |
19 | */ |
20 | ||
5f76b90f | 21 | #ifndef _GNU_SOURCE |
22 | #define _GNU_SOURCE 1 | |
23 | #endif | |
dd94de5a | 24 | #include <alloca.h> |
5f76b90f | 25 | #include <macro.h> |
26 | #include <mntent.h> | |
edaf8b1b SG |
27 | #include <stdio.h> |
28 | #include <string.h> | |
edaf8b1b SG |
29 | |
30 | /* Since the values in a line are separated by spaces, a name cannot | |
5f76b90f | 31 | * contain a space. Therefore some programs encode spaces in names |
32 | * by the strings "\040". We undo the encoding when reading an entry. | |
33 | * The decoding happens in place. | |
34 | */ | |
35 | static char *decode_name(char *buf) | |
edaf8b1b | 36 | { |
5f76b90f | 37 | char *rp = buf; |
38 | char *wp = buf; | |
39 | ||
40 | do { | |
41 | if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '4' && | |
42 | rp[3] == '0') { | |
43 | /* \040 is a SPACE. */ | |
44 | *wp++ = ' '; | |
45 | rp += 3; | |
46 | } else if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '1' && | |
47 | rp[3] == '1') { | |
48 | /* \011 is a TAB. */ | |
49 | *wp++ = '\t'; | |
50 | rp += 3; | |
51 | } else if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '1' && | |
52 | rp[3] == '2') { | |
53 | /* \012 is a NEWLINE. */ | |
54 | *wp++ = '\n'; | |
55 | rp += 3; | |
56 | } else if (rp[0] == '\\' && rp[1] == '\\') { | |
57 | /* We have to escape \\ to be able to represent all characters. */ | |
58 | *wp++ = '\\'; | |
59 | rp += 1; | |
60 | } else if (rp[0] == '\\' && rp[1] == '1' && rp[2] == '3' && | |
61 | rp[3] == '4') { | |
62 | /* \134 is also \\. */ | |
63 | *wp++ = '\\'; | |
64 | rp += 3; | |
65 | } else { | |
66 | *wp++ = *rp; | |
67 | } | |
68 | } while (*rp++ != '\0'); | |
69 | ||
70 | return buf; | |
edaf8b1b SG |
71 | } |
72 | ||
73 | /* Read one mount table entry from STREAM. Returns a pointer to storage | |
5f76b90f | 74 | * reused on the next call, or null for EOF or error (use feof/ferror to check). |
75 | */ | |
76 | struct mntent *getmntent_r(FILE *stream, struct mntent *mp, char *buffer, int bufsiz) | |
edaf8b1b | 77 | { |
5f76b90f | 78 | char *cp; |
79 | char *head; | |
80 | ||
81 | do { | |
82 | char *end_ptr; | |
83 | ||
84 | if (!fgets(buffer, bufsiz, stream)) | |
85 | return NULL; | |
86 | ||
87 | end_ptr = strchr(buffer, '\n'); | |
88 | if (end_ptr != NULL) { | |
89 | /* chop newline */ | |
90 | *end_ptr = '\0'; | |
91 | } else { | |
92 | /* Not the whole line was read. Do it now but forget it. */ | |
93 | char tmp[1024] = {0}; | |
94 | ||
95 | while (fgets(tmp, sizeof tmp, stream)) | |
96 | if (strchr(tmp, '\n') != NULL) | |
97 | break; | |
98 | } | |
99 | ||
100 | head = buffer + strspn(buffer, " \t"); | |
101 | /* skip empty lines and comment lines: */ | |
102 | } while (head[0] == '\0' || head[0] == '#'); | |
103 | ||
104 | cp = strsep(&head, " \t"); | |
105 | mp->mnt_fsname = cp ? decode_name(cp) : (char *)""; | |
106 | if (head) | |
107 | head += strspn(head, " \t"); | |
108 | ||
109 | cp = strsep(&head, " \t"); | |
110 | mp->mnt_dir = cp ? decode_name(cp) : (char *)""; | |
111 | if (head) | |
112 | head += strspn(head, " \t"); | |
113 | ||
114 | cp = strsep(&head, " \t"); | |
115 | mp->mnt_type = cp ? decode_name(cp) : (char *)""; | |
116 | if (head) | |
117 | head += strspn(head, " \t"); | |
118 | ||
119 | cp = strsep(&head, " \t"); | |
120 | mp->mnt_opts = cp ? decode_name(cp) : (char *)""; | |
121 | if (head) { | |
122 | int ret = sscanf(head, " %d %d ", &mp->mnt_freq, &mp->mnt_passno); | |
123 | ||
124 | switch (ret) { | |
125 | case 0: | |
126 | mp->mnt_freq = 0; | |
127 | case 1: | |
128 | mp->mnt_passno = 0; | |
129 | case 2: | |
130 | break; | |
131 | } | |
132 | } else { | |
133 | mp->mnt_freq = 0; | |
134 | } | |
135 | ||
136 | return mp; | |
edaf8b1b SG |
137 | } |
138 | ||
5f76b90f | 139 | struct mntent *getmntent(FILE *stream) |
edaf8b1b | 140 | { |
5f76b90f | 141 | static struct mntent m; |
142 | static char *getmntent_buffer; | |
edaf8b1b | 143 | |
5f76b90f | 144 | if (!getmntent_buffer) { |
145 | getmntent_buffer = (char *)malloc(LXC_MAX_BUFFER); | |
146 | if (!getmntent_buffer) | |
147 | return NULL; | |
148 | } | |
edaf8b1b | 149 | |
5f76b90f | 150 | return getmntent_r(stream, &m, getmntent_buffer, LXC_MAX_BUFFER); |
edaf8b1b SG |
151 | } |
152 | ||
edaf8b1b | 153 | /* Prepare to begin reading and/or writing mount table entries from the |
5f76b90f | 154 | * beginning of FILE. MODE is as for `fopen'. |
155 | */ | |
156 | FILE *setmntent(const char *file, const char *mode) | |
edaf8b1b | 157 | { |
5f76b90f | 158 | /* Extend the mode parameter with "c" to disable cancellation in the |
159 | * I/O functions and "e" to set FD_CLOEXEC. | |
160 | */ | |
161 | size_t modelen = strlen(mode); | |
162 | char *newmode; | |
dd94de5a | 163 | |
5f76b90f | 164 | newmode = alloca(modelen + 3); |
dd94de5a | 165 | |
5f76b90f | 166 | memcpy(newmode, mode, modelen); |
167 | memcpy(newmode + modelen, "ce", 3); | |
edaf8b1b | 168 | |
5f76b90f | 169 | return fopen (file, newmode); |
edaf8b1b SG |
170 | } |
171 | ||
edaf8b1b | 172 | /* Close a stream opened with `setmntent'. */ |
5f76b90f | 173 | int endmntent(FILE *stream) |
edaf8b1b | 174 | { |
5f76b90f | 175 | /* SunOS 4.x allows for NULL stream */ |
176 | if (stream) | |
177 | fclose(stream); | |
178 | ||
179 | /* SunOS 4.x says to always return 1 */ | |
180 | return 1; | |
edaf8b1b SG |
181 | } |
182 | ||
183 | /* Search MNT->mnt_opts for an option matching OPT. | |
5f76b90f | 184 | * Returns the address of the substring, or null if none found. |
185 | */ | |
186 | char *hasmntopt(const struct mntent *mnt, const char *opt) | |
edaf8b1b | 187 | { |
5f76b90f | 188 | const size_t optlen = strlen(opt); |
189 | char *rest = mnt->mnt_opts, *p; | |
190 | ||
191 | while ((p = strstr(rest, opt))) { | |
192 | if ((p == rest || p[-1] == ',') && | |
193 | (p[optlen] == '\0' || p[optlen] == '=' || p[optlen] == ',')) | |
194 | return p; | |
195 | ||
196 | rest = strchr(p, ','); | |
197 | if (!rest) | |
198 | break; | |
199 | ||
200 | ++rest; | |
201 | } | |
202 | ||
203 | return NULL; | |
edaf8b1b | 204 | } |