1 /* Utilities for reading/writing fstab, mtab, etc.
2 Copyright (C) 1995-2000, 2001 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
19
20 #include <alloca.h>
21 #include <mntent.h>
22 #include <stdio.h>
23 #include <string.h>
24 #include <sys/types.h>
25 #include <machine/weakalias.h>
26
27 /* Prepare to begin reading and/or writing mount table entries from the
28 beginning of FILE. MODE is as for `fopen'. */
29 FILE *
__setmntent(const char * file,const char * mode)30 __setmntent (const char *file, const char *mode)
31 {
32 FILE *result = fopen (file, mode);
33
34 return result;
35 }
weak_alias(__setmntent,setmntent)36 weak_alias (__setmntent, setmntent)
37
38
39 /* Close a stream opened with `setmntent'. */
40 int
41 __endmntent (FILE *stream)
42 {
43 if (stream) /* SunOS 4.x allows for NULL stream */
44 fclose (stream);
45 return 1; /* SunOS 4.x says to always return 1 */
46 }
weak_alias(__endmntent,endmntent)47 weak_alias (__endmntent, endmntent)
48
49
50 /* Since the values in a line are separated by spaces, a name cannot
51 contain a space. Therefore some programs encode spaces in names
52 by the strings "\040". We undo the encoding when reading an entry.
53 The decoding happens in place. */
54 static char *
55 decode_name (char *buf)
56 {
57 char *rp = buf;
58 char *wp = buf;
59
60 do
61 if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '4' && rp[3] == '0')
62 {
63 /* \040 is a SPACE. */
64 *wp++ = ' ';
65 rp += 3;
66 }
67 else if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '1' && rp[3] == '2')
68 {
69 /* \012 is a TAB. */
70 *wp++ = '\t';
71 rp += 3;
72 }
73 else if (rp[0] == '\\' && rp[1] == '\\')
74 {
75 /* We have to escape \\ to be able to represent all characters. */
76 *wp++ = '\\';
77 rp += 1;
78 }
79 else
80 *wp++ = *rp;
81 while (*rp++ != '\0');
82
83 return buf;
84 }
85
86
87 /* Read one mount table entry from STREAM. Returns a pointer to storage
88 reused on the next call, or null for EOF or error (use feof/ferror to
89 check). */
90 struct mntent *
__getmntent_r(FILE * stream,struct mntent * mp,char * buffer,int bufsiz)91 __getmntent_r (FILE *stream, struct mntent *mp, char *buffer, int bufsiz)
92 {
93 char *cp;
94 char *head;
95
96 flockfile (stream);
97 do
98 {
99 char *end_ptr;
100
101 if (fgets (buffer, bufsiz, stream) == NULL)
102 {
103 funlockfile (stream);
104 return NULL;
105 }
106
107 end_ptr = strchr (buffer, '\n');
108 if (end_ptr != NULL) /* chop newline */
109 *end_ptr = '\0';
110 else
111 {
112 /* Not the whole line was read. Do it now but forget it. */
113 char tmp[1024];
114 while (fgets (tmp, sizeof tmp, stream) != NULL)
115 if (strchr (tmp, '\n') != NULL)
116 break;
117 }
118
119 head = buffer + strspn (buffer, " \t");
120 /* skip empty lines and comment lines: */
121 }
122 while (head[0] == '\0' || head[0] == '#');
123
124 cp = strsep (&head, " \t");
125 mp->mnt_fsname = cp != NULL ? decode_name (cp) : (char *) "";
126 if (head)
127 head += strspn (head, " \t");
128 cp = strsep (&head, " \t");
129 mp->mnt_dir = cp != NULL ? decode_name (cp) : (char *) "";
130 if (head)
131 head += strspn (head, " \t");
132 cp = strsep (&head, " \t");
133 mp->mnt_type = cp != NULL ? decode_name (cp) : (char *) "";
134 if (head)
135 head += strspn (head, " \t");
136 cp = strsep (&head, " \t");
137 mp->mnt_opts = cp != NULL ? decode_name (cp) : (char *) "";
138 switch (head ? sscanf (head, " %d %d ", &mp->mnt_freq, &mp->mnt_passno) : 0)
139 {
140 case 0:
141 mp->mnt_freq = 0;
142 case 1:
143 mp->mnt_passno = 0;
144 case 2:
145 break;
146 }
147 funlockfile (stream);
148
149 return mp;
150 }
weak_alias(__getmntent_r,getmntent_r)151 weak_alias (__getmntent_r, getmntent_r)
152
153
154 /* We have to use an encoding for names if they contain spaces or tabs.
155 To be able to represent all characters we also have to escape the
156 backslash itself. This "function" must be a macro since we use
157 `alloca'. */
158 #define encode_name(name) \
159 do { \
160 const char *rp = name; \
161 \
162 while (*rp != '\0') \
163 if (*rp == ' ' || *rp == '\t' || *rp == '\\') \
164 break; \
165 else \
166 ++rp; \
167 \
168 if (*rp != '\0') \
169 { \
170 /* In the worst case the length of the string can increase to \
171 founr times the current length. */ \
172 char *wp; \
173 \
174 rp = name; \
175 name = wp = (char *) alloca (strlen (name) * 4 + 1); \
176 \
177 do \
178 if (*rp == ' ') \
179 { \
180 *wp++ = '\\'; \
181 *wp++ = '0'; \
182 *wp++ = '4'; \
183 *wp++ = '0'; \
184 } \
185 else if (*rp == '\t') \
186 { \
187 *wp++ = '\\'; \
188 *wp++ = '0'; \
189 *wp++ = '1'; \
190 *wp++ = '2'; \
191 } \
192 else if (*rp == '\\') \
193 { \
194 *wp++ = '\\'; \
195 *wp++ = '\\'; \
196 } \
197 else \
198 *wp++ = *rp; \
199 while (*rp++ != '\0'); \
200 } \
201 } while (0)
202
203
204 /* Write the mount table entry described by MNT to STREAM.
205 Return zero on success, nonzero on failure. */
206 int
207 __addmntent (FILE *stream, const struct mntent *mnt)
208 {
209 struct mntent mntcopy = *mnt;
210 if (fseek (stream, 0, SEEK_END))
211 return 1;
212
213 /* Encode spaces and tabs in the names. */
214 encode_name (mntcopy.mnt_fsname);
215 encode_name (mntcopy.mnt_dir);
216 encode_name (mntcopy.mnt_type);
217 encode_name (mntcopy.mnt_opts);
218
219 return (fprintf (stream, "%s %s %s %s %d %d\n",
220 mntcopy.mnt_fsname,
221 mntcopy.mnt_dir,
222 mntcopy.mnt_type,
223 mntcopy.mnt_opts,
224 mntcopy.mnt_freq,
225 mntcopy.mnt_passno)
226 < 0 ? 1 : 0);
227 }
weak_alias(__addmntent,addmntent)228 weak_alias (__addmntent, addmntent)
229
230
231 /* Search MNT->mnt_opts for an option matching OPT.
232 Returns the address of the substring, or null if none found. */
233 char *
234 __hasmntopt (const struct mntent *mnt, const char *opt)
235 {
236 const size_t optlen = strlen (opt);
237 char *rest = mnt->mnt_opts, *p;
238
239 while ((p = strstr (rest, opt)) != NULL)
240 {
241 if (p == rest
242 || (p[-1] == ','
243 && (p[optlen] == '\0' ||
244 p[optlen] == '=' ||
245 p[optlen] == ',')))
246 return p;
247
248 rest = strchr (rest, ',');
249 if (rest == NULL)
250 break;
251 ++rest;
252 }
253
254 return NULL;
255 }
256 weak_alias (__hasmntopt, hasmntopt)
257