1/*	$NetBSD$	*/
2
3/*
4 * Copyright (c) 1997-2009 Erez Zadok
5 * Copyright (c) 1990 Jan-Simon Pendry
6 * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
7 * Copyright (c) 1990 The Regents of the University of California.
8 * All rights reserved.
9 *
10 * This code is derived from software contributed to Berkeley by
11 * Jan-Simon Pendry at Imperial College, London.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 * 3. All advertising materials mentioning features or use of this software
22 *    must display the following acknowledgment:
23 *      This product includes software developed by the University of
24 *      California, Berkeley and its contributors.
25 * 4. Neither the name of the University nor the names of its contributors
26 *    may be used to endorse or promote products derived from this software
27 *    without specific prior written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 * SUCH DAMAGE.
40 *
41 *
42 * File: am-utils/conf/mtab/mtab_isc3.c
43 *
44 */
45
46#ifdef HAVE_CONFIG_H
47# include <config.h>
48#endif /* HAVE_CONFIG_H */
49#include <am_defs.h>
50#include <amu.h>
51
52/* fd for /etc/.mnt.lock (also act as flag for: is_locked) */
53static int mtlckf = 0;
54static char mtlckname[] = "/etc/.mnt.lock";
55static char mnttabname[] = "/etc/mnttab";
56
57
58static void
59unlockmnttab(void)
60{
61  if (mtlckf) {
62    close(mtlckf);
63    mtlckf = 0;
64  }
65}
66
67
68static
69lockfile(int fd, int type)
70{
71  struct flock lk;
72
73  lk.l_type = type;
74  lk.l_whence = 0;
75  lk.l_start = 0;
76  lk.l_len = 0;
77
78  return fcntl(fd, F_SETLKW, &lk);
79}
80
81
82static
83lockmnttab(void)
84{
85  if (mtlckf == 0) {		/* need lock on /etc/.mnt.lock */
86    mtlckf = open(mtlckname, O_RDWR);
87    if (mtlckf >= 0) {
88      if (lockfile(mtlckf, F_WRLCK) < 0) {
89	close(mtlckf);
90	mtlckf = 0;
91#ifdef DEBUG
92	dlog("lock failed %m");
93#endif /* DEBUG */
94      } else {
95	return 0;
96      }
97    }
98  }
99  plog(XLOG_ERROR, "Unable to lock %s: %m", mtlckname);
100  return -1;
101}
102
103
104void
105unlock_mntlist(void)
106{
107  dlog("unlock_mntlist: releasing");
108  unlockmnttab();
109}
110
111
112/* convert from ix386 mnttab to amd mntent */
113static mntent_t *
114mnt_dup(mntent_t *mp)
115{
116  /* note: may not be null terminated */
117  mntent_t *new_mp = ALLOC(mntent_t);
118  char nullcpy[128];
119
120  xstrlcpy(nullcpy, mp->mt_dev, 32);
121  new_mp->mnt_fsname = strdup(nullcpy);
122
123  xstrlcpy(nullcpy, mp->mt_filsys, 32);
124  new_mp->mnt_dir = strdup(nullcpy);
125
126  xstrlcpy(nullcpy, mp->mt_fstyp, 16);
127  new_mp->mnt_type = strdup(nullcpy);
128
129  xstrlcpy(nullcpy, mp->mt_mntopts, 64);
130  new_mp->mnt_opts = strdup(nullcpy);
131
132  new_mp->mnt_freq = 0;
133  new_mp->mnt_passno = 0;
134
135  new_mp->mnt_time = mp->mt_time;
136  new_mp->mnt_ro = mp->mt_ro_flg;
137
138  return new_mp;
139}
140
141
142/* convert back (static alloc) */
143static mntent_t *
144mtab_of(mntent_t *mnt)
145{
146  static mntent_t mt;
147
148  xstrlcpy(mt.mt_dev, mnt->mnt_fsname, 32);
149  xstrlcpy(mt.mt_filsys, mnt->mnt_dir, 32);
150
151  mt.mt_ro_flg = mnt->mnt_ro;
152  mt.mt_time = mnt->mnt_time;
153
154  xstrlcpy(mt.mt_fstyp, mnt->mnt_type, 16);
155  xstrlcpy(mt.mt_mntopts, mnt->mnt_opts, 64);
156
157  return &mt;
158}
159
160
161/*
162 * Read a mount table into memory
163 */
164mntlist *
165read_mtab(char *fs, const char *mnttabname)
166{
167  mntlist **mpp, *mhp;
168  /* From: Piete Brooks <pb@cl.cam.ac.uk> */
169  int fd;
170  mntent_t mountbuffer[NMOUNT], *fs_data;
171  int ret;
172  int nmts;
173
174  if (lockmnttab() != 0)
175    return (mntlist *) NULL;
176
177  fd = open(mnttabname, O_RDONLY);
178  if (fd < 0) {
179    plog(XLOG_ERROR, "Can't open %s: %m", mnttabname);
180    return (mntlist *) NULL;
181  }
182  mpp = &mhp;
183  while ((ret = read(fd, (char *) mountbuffer, NMOUNT * sizeof(mntent_t))) > 0) {
184    nmts = ret / sizeof(mntent_t);
185    for (fs_data = mountbuffer; fs_data < &mountbuffer[nmts]; fs_data++) {
186      /*
187       * Allocate a new slot
188       */
189      *mpp = ALLOC(struct mntlist);
190
191      /*
192       * Copy the data returned by getmntent
193       */
194      (*mpp)->mnt = mnt_dup(fs_data);
195
196      /*
197       * Move to next pointer
198       */
199      mpp = &(*mpp)->mnext;
200    }
201  }
202  if (ret < 0) {
203    plog(XLOG_ERROR, "read error on %s: %m", mnttabname);
204    unlockmnttab();
205    mhp = (mntlist *) NULL;
206  }
207  *mpp = NULL;
208
209  close(fd);
210  return mhp;
211}
212
213
214static
215write_mntent_to_mtab(int fd, mntent_t *mnt)
216{
217  int wr;
218
219eagain:
220  wr = write(fd, (char *) mtab_of(mnt), sizeof(mntent_t));
221  if (wr < 0) {
222    switch (wr) {
223    case EAGAIN:
224      goto eagain;
225    default:
226      return -1;
227    }
228  }
229  if (wr != sizeof(mntent_t))
230      plog(XLOG_ERROR, "Can't write entry to %s: %m", mnttabname);
231  return 0;
232}
233
234
235void
236rewrite_mtab(mntlist *mp, const char *mnttabname)
237{
238  int fd;
239
240  assert(mtlckf != 0);
241
242  fd = open(mnttabname, O_RDWR | O_TRUNC);
243  if (fd < 0) {
244    plog(XLOG_ERROR, "Can't open %s: %m", mnttabname);
245    unlockmnttab();
246  }
247  while (mp) {
248    if (mp->mnt)
249      write_mntent_to_mtab(fd, mp->mnt);
250    mp = mp->mnext;
251  }
252
253  close(fd);
254  unlockmnttab();
255}
256
257
258void
259write_mntent(mntent_t *mp, const char *mnttabname)
260{
261  int fd;
262
263  if (lockmnttab() == -1)
264    return;
265
266  fd = open(mnttabname, O_RDWR | O_APPEND);
267  if (fd < 0) {
268    plog(XLOG_ERROR, "Unable to append %s: %m", mnttabname);
269    return;
270  }
271  write_mntent_to_mtab(fd, mp);
272
273  close(fd);
274  unlockmnttab();
275}
276