xref: /titanic_44/usr/src/lib/libc/port/gen/getmntent.c (revision 7c478bd95313f5f23a4c958a745db2134aa03244)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*	Copyright (c) 1988 AT&T	*/
30 /*	  All Rights Reserved  	*/
31 
32 
33 #pragma weak getmntany = _getmntany
34 #pragma weak getmntent = _getmntent
35 #pragma weak getextmntent = _getextmntent
36 #pragma weak resetmnttab = _resetmnttab
37 #pragma weak hasmntopt = _hasmntopt
38 
39 #include "synonyms.h"
40 #include <mtlib.h>
41 #include <stdio.h>
42 #include <sys/types.h>
43 #include <sys/stat.h>
44 #include <sys/mnttab.h>
45 #include <sys/mntio.h>
46 #include <string.h>
47 #include <ctype.h>
48 #include <errno.h>
49 #include <stdlib.h>
50 #include <thread.h>
51 #include <synch.h>
52 #include <libc.h>
53 #include <unistd.h>
54 #include "tsd.h"
55 
56 static int getmntent_compat(FILE *fp, struct mnttab *mp);
57 static int convert_mntent(struct extmnttab *, struct extmnttab *, int);
58 
59 #define	GETTOK_R(xx, ll, tmp)\
60 	if ((mp->xx = (char *)strtok_r(ll, sepstr, tmp)) == NULL)\
61 		return (MNT_TOOFEW);\
62 	if (strcmp(mp->xx, dash) == 0)\
63 		mp->xx = NULL
64 
65 #define	DIFF(xx)\
66 	(mrefp->xx != NULL && (mgetp->xx == NULL ||\
67 	    strcmp(mrefp->xx, mgetp->xx) != 0))
68 
69 #define	SDIFF(xx, typem, typer)\
70 	((mgetp->xx == NULL) || (stat64(mgetp->xx, &statb) == -1) ||\
71 	((statb.st_mode & S_IFMT) != typem) ||\
72 	    (statb.st_rdev != typer))
73 
74 static const char	sepstr[] = " \t\n";
75 static const char	dash[] = "-";
76 
77 typedef struct {
78 	size_t	buflen;
79 	char	*buf;
80 } thread_data_t;
81 
82 static void
83 destroy_thread_data(void *arg)
84 {
85 	thread_data_t *thread_data = arg;
86 
87 	if (thread_data->buf != NULL) {
88 		free(thread_data->buf);
89 		thread_data->buf = NULL;
90 	}
91 	thread_data->buflen = 0;
92 }
93 
94 static char *
95 getmntbuf(size_t size)
96 {
97 	thread_data_t *thread_data;
98 
99 	if (size < MNT_LINE_MAX)
100 		size = MNT_LINE_MAX;
101 
102 	thread_data = tsdalloc(_T_GETMNTENT,
103 	    sizeof (thread_data_t), destroy_thread_data);
104 	if (thread_data == NULL)
105 		return (NULL);
106 	if (thread_data->buf == NULL ||
107 	    thread_data->buflen < size) {
108 		if (thread_data->buf != NULL)
109 			free(thread_data->buf);
110 		thread_data->buflen = 0;
111 		if ((thread_data->buf = malloc(size)) == NULL)
112 			return (NULL);
113 		thread_data->buflen = size;
114 	}
115 	return (thread_data->buf);
116 }
117 
118 int
119 getmntany(FILE *fp, struct mnttab *mgetp, struct mnttab *mrefp)
120 {
121 	int	ret, bstat;
122 	mode_t	bmode;
123 	dev_t	brdev;
124 	struct stat64	statb;
125 
126 	if (mrefp->mnt_special && stat64(mrefp->mnt_special, &statb) == 0 &&
127 	    ((bmode = (statb.st_mode & S_IFMT)) == S_IFBLK ||
128 	    bmode == S_IFCHR)) {
129 		bstat = 1;
130 		brdev = statb.st_rdev;
131 	} else {
132 		bstat = 0;
133 	}
134 
135 	while ((ret = getmntent(fp, mgetp)) == 0 &&
136 	    ((bstat == 0 && DIFF(mnt_special)) ||
137 	    (bstat == 1 && SDIFF(mnt_special, bmode, brdev)) ||
138 	    DIFF(mnt_mountp) ||
139 	    DIFF(mnt_fstype) ||
140 	    DIFF(mnt_mntopts) ||
141 	    DIFF(mnt_time)))
142 		;
143 
144 	return (ret);
145 }
146 
147 int
148 getmntent(FILE *fp, struct mnttab *mp)
149 {
150 	int	ret;
151 	struct	extmnttab *emp;
152 
153 	ret = ioctl(fileno(fp), MNTIOC_GETMNTENT, &emp);
154 
155 	switch (ret) {
156 		case 0:
157 			return (convert_mntent(emp, (struct extmnttab *)mp, 0));
158 		case 1:
159 			return (-1);
160 		default:
161 			return (getmntent_compat(fp, mp));
162 	}
163 }
164 
165 char *
166 mntopt(char **p)
167 {
168 	char *cp = *p;
169 	char *retstr;
170 
171 	while (*cp && isspace(*cp))
172 		cp++;
173 
174 	retstr = cp;
175 	while (*cp && *cp != ',')
176 		cp++;
177 
178 	if (*cp) {
179 		*cp = '\0';
180 		cp++;
181 	}
182 
183 	*p = cp;
184 	return (retstr);
185 }
186 
187 char *
188 hasmntopt(struct mnttab *mnt, char *opt)
189 {
190 	char tmpopts[MNT_LINE_MAX];
191 	char *f, *opts = tmpopts;
192 
193 	if (mnt->mnt_mntopts == NULL)
194 		return (NULL);
195 	(void) strcpy(opts, mnt->mnt_mntopts);
196 	f = mntopt(&opts);
197 	for (; *f; f = mntopt(&opts)) {
198 		if (strncmp(opt, f, strlen(opt)) == 0)
199 			return (f - tmpopts + mnt->mnt_mntopts);
200 	}
201 	return (NULL);
202 }
203 
204 /*ARGSUSED*/
205 int
206 getextmntent(FILE *fp, struct extmnttab *mp, size_t len)
207 {
208 	int	ret;
209 	struct	extmnttab *emp;
210 
211 	ret = ioctl(fileno(fp), MNTIOC_GETMNTENT, &emp);
212 
213 	switch (ret) {
214 		case 0:
215 			return (convert_mntent(emp, mp, 1));
216 		case 1:
217 			return (-1);
218 		default:
219 			return (ret);
220 	}
221 }
222 
223 void
224 resetmnttab(FILE *fp)
225 {
226 	rewind(fp);
227 }
228 
229 /*
230  * This is a horrible function, necessary to support this broken interface.
231  * Some callers of get(ext)mntent assume that the memory is valid even after the
232  * file is closed.  Since we switched to a direct ioctl() interface, this is no
233  * longer true.  In order to support these apps, we have to put the data into a
234  * thread specific buffer.
235  */
236 static int
237 convert_mntent(struct extmnttab *src, struct extmnttab *dst, int isext)
238 {
239 	size_t len;
240 	char *buf;
241 
242 	len = src->mnt_time - src->mnt_special + strlen(src->mnt_time) + 1;
243 
244 	buf = getmntbuf(len);
245 	if (buf == NULL) {
246 		errno = ENOMEM;
247 		return (-1);
248 	}
249 
250 	memcpy(buf, src->mnt_special, len);
251 	dst->mnt_special = buf;
252 	dst->mnt_mountp = buf + (src->mnt_mountp - src->mnt_special);
253 	dst->mnt_fstype = buf + (src->mnt_fstype - src->mnt_special);
254 	dst->mnt_mntopts = buf + (src->mnt_mntopts - src->mnt_special);
255 	dst->mnt_time = buf + (src->mnt_time - src->mnt_special);
256 	if (isext) {
257 		dst->mnt_major = src->mnt_major;
258 		dst->mnt_minor = src->mnt_minor;
259 	}
260 
261 	return (0);
262 }
263 
264 /*
265  * Compatibility for non-mntfs files.  For backwards compatibility, we continue
266  * to have to support this broken interface.  Note that getextmntent() has
267  * always failed when using a file other than /etc/mnttab, because it relies on
268  * an ioctl() call.
269  */
270 static int
271 getline(char *lp, FILE *fp)
272 {
273 	char	*cp;
274 
275 	while ((lp = fgets(lp, MNT_LINE_MAX, fp)) != NULL) {
276 		if (strlen(lp) == MNT_LINE_MAX-1 && lp[MNT_LINE_MAX-2] != '\n')
277 			return (MNT_TOOLONG);
278 
279 		for (cp = lp; *cp == ' ' || *cp == '\t'; cp++)
280 			;
281 
282 		if (*cp != '#' && *cp != '\n')
283 			return (0);
284 	}
285 	return (-1);
286 }
287 
288 static int
289 getmntent_compat(FILE *fp, struct mnttab *mp)
290 {
291 	int	ret;
292 	char	*tmp;
293 	char	*line = getmntbuf(MNT_LINE_MAX);
294 
295 	if (line == NULL) {
296 		errno = ENOMEM;
297 		return (-1);
298 	}
299 
300 	/* skip leading spaces and comments */
301 	if ((ret = getline(line, fp)) != 0)
302 		return (ret);
303 
304 	/* split up each field */
305 	GETTOK_R(mnt_special, line, &tmp);
306 	GETTOK_R(mnt_mountp, NULL, &tmp);
307 	GETTOK_R(mnt_fstype, NULL, &tmp);
308 	GETTOK_R(mnt_mntopts, NULL, &tmp);
309 	GETTOK_R(mnt_time, NULL, &tmp);
310 
311 	/* check for too many fields */
312 	if (strtok_r(NULL, sepstr, &tmp) != NULL)
313 		return (MNT_TOOMANY);
314 
315 	return (0);
316 }
317