1/*
2 * Copyright (c) 1997-2006 Erez Zadok
3 * Copyright (c) 1990 Jan-Simon Pendry
4 * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
5 * Copyright (c) 1990 The Regents of the University of California.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Jan-Simon Pendry at Imperial College, London.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgment:
21 *      This product includes software developed by the University of
22 *      California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 *
40 * File: am-utils/amd/amfs_toplvl.c
41 *
42 */
43
44/*
45 * Top-level file system
46 */
47
48#ifdef HAVE_CONFIG_H
49# include <config.h>
50#endif /* HAVE_CONFIG_H */
51#include <am_defs.h>
52#include <amd.h>
53
54/****************************************************************************
55 *** FORWARD DEFINITIONS                                                  ***
56 ****************************************************************************/
57static int amfs_toplvl_init(mntfs *mf);
58
59/****************************************************************************
60 *** OPS STRUCTURES                                                       ***
61 ****************************************************************************/
62am_ops amfs_toplvl_ops =
63{
64  "toplvl",
65  amfs_generic_match,
66  amfs_toplvl_init,		/* amfs_toplvl_init */
67  amfs_toplvl_mount,
68  amfs_toplvl_umount,
69  amfs_generic_lookup_child,
70  amfs_generic_mount_child,
71  amfs_generic_readdir,
72  0,				/* amfs_toplvl_readlink */
73  amfs_generic_mounted,
74  0,				/* amfs_toplvl_umounted */
75  amfs_generic_find_srvr,
76  0,				/* amfs_toplvl_get_wchan */
77  FS_MKMNT | FS_NOTIMEOUT | FS_BACKGROUND |
78	  FS_AMQINFO | FS_DIRECTORY, /* nfs_fs_flags */
79#ifdef HAVE_FS_AUTOFS
80  AUTOFS_TOPLVL_FS_FLAGS,
81#endif /* HAVE_FS_AUTOFS */
82};
83
84
85/****************************************************************************
86 *** FUNCTIONS                                                             ***
87 ****************************************************************************/
88
89static void
90set_auto_attrcache_timeout(char *preopts, char *opts, size_t l)
91{
92
93#ifdef MNTTAB_OPT_NOAC
94  /*
95   * Don't cache attributes - they are changing under the kernel's feet.
96   * For example, IRIX5.2 will dispense with nfs lookup calls and hand stale
97   * filehandles to getattr unless we disable attribute caching on the
98   * automount points.
99   */
100  if (gopt.auto_attrcache == 0) {
101    xsnprintf(preopts, l, ",%s", MNTTAB_OPT_NOAC);
102    xstrlcat(opts, preopts, l);
103  }
104#endif /* MNTTAB_OPT_NOAC */
105
106  /*
107   * XXX: note that setting these to 0 in the past resulted in an error on
108   * some systems, which is why it's better to use "noac" if possible.  For
109   * now, we're setting everything possible, but if this will cause trouble,
110   * then we'll have to condition the remainder of this on OPT_NOAC.
111   */
112#ifdef MNTTAB_OPT_ACTIMEO
113  xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTIMEO, gopt.auto_attrcache);
114  xstrlcat(opts, preopts, l);
115#else /* MNTTAB_OPT_ACTIMEO */
116# ifdef MNTTAB_OPT_ACDIRMIN
117  xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTDIRMIN, gopt.auto_attrcache);
118  xstrlcat(opts, preopts, l);
119# endif /* MNTTAB_OPT_ACDIRMIN */
120# ifdef MNTTAB_OPT_ACDIRMAX
121  xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTDIRMAX, gopt.auto_attrcache);
122  xstrlcat(opts, preopts, l);
123# endif /* MNTTAB_OPT_ACDIRMAX */
124# ifdef MNTTAB_OPT_ACREGMIN
125  xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTREGMIN, gopt.auto_attrcache);
126  xstrlcat(opts, preopts, l);
127# endif /* MNTTAB_OPT_ACREGMIN */
128# ifdef MNTTAB_OPT_ACREGMAX
129  xsnprintf(preopts, l, ",%s=%d", MNTTAB_OPT_ACTREGMAX, gopt.auto_attrcache);
130  xstrlcat(opts, preopts, l);
131# endif /* MNTTAB_OPT_ACREGMAX */
132#endif /* MNTTAB_OPT_ACTIMEO */
133}
134
135
136/*
137 * Initialize a top-level mount.  In our case, if the user asked for
138 * forced_unmounts, and the OS supports it, then we try forced/lazy unmounts
139 * on any previous toplvl mounts.  This is useful if a previous Amd died and
140 * left behind toplvl mount points (this Amd will clean them up).
141 *
142 * WARNING: Don't use forced/lazy unmounts if you have another valid Amd
143 * running, because this code WILL force those valid toplvl mount points to
144 * be detached as well!
145 */
146static int
147amfs_toplvl_init(mntfs *mf)
148{
149  int error = 0;
150
151#if defined(MNT2_GEN_OPT_FORCE) || defined(MNT2_GEN_OPT_DETACH)
152  if (gopt.flags & CFM_FORCED_UNMOUNTS) {
153    plog(XLOG_INFO, "amfs_toplvl_init: trying forced/lazy unmount of %s",
154	 mf->mf_mount);
155    error = umount2_fs(mf->mf_mount, AMU_UMOUNT_FORCE | AMU_UMOUNT_DETACH);
156    if (error)
157      plog(XLOG_INFO, "amfs_toplvl_init: forced/lazy unmount failed: %m");
158    else
159      dlog("amfs_toplvl_init: forced/lazy unmount succeeded");
160  }
161#endif /* MNT2_GEN_OPT_FORCE || MNT2_GEN_OPT_DETACH */
162  return error;
163}
164
165
166/*
167 * Mount the top-level
168 */
169int
170amfs_toplvl_mount(am_node *mp, mntfs *mf)
171{
172  struct stat stb;
173  char opts[SIZEOF_OPTS], preopts[SIZEOF_OPTS], toplvl_opts[40];
174  int error;
175
176  /*
177   * Mounting the automounter.
178   * Make sure the mount directory exists, construct
179   * the mount options and call the mount_amfs_toplvl routine.
180   */
181
182  if (stat(mp->am_path, &stb) < 0) {
183    return errno;
184  } else if ((stb.st_mode & S_IFMT) != S_IFDIR) {
185    plog(XLOG_WARNING, "%s is not a directory", mp->am_path);
186    return ENOTDIR;
187  }
188
189  /*
190   * Construct some mount options:
191   *
192   * Tack on magic map=<mapname> option in mtab to emulate
193   * SunOS automounter behavior.
194   */
195
196#ifdef HAVE_FS_AUTOFS
197  if (mf->mf_flags & MFF_IS_AUTOFS) {
198    autofs_get_opts(opts, sizeof(opts), mp->am_autofs_fh);
199  } else
200#endif /* HAVE_FS_AUTOFS */
201  {
202    preopts[0] = '\0';
203#ifdef MNTTAB_OPT_INTR
204    xstrlcat(preopts, MNTTAB_OPT_INTR, sizeof(preopts));
205    xstrlcat(preopts, ",", sizeof(preopts));
206#endif /* MNTTAB_OPT_INTR */
207#ifdef MNTTAB_OPT_IGNORE
208    xstrlcat(preopts, MNTTAB_OPT_IGNORE, sizeof(preopts));
209    xstrlcat(preopts, ",", sizeof(preopts));
210#endif /* MNTTAB_OPT_IGNORE */
211    /* write most of the initial options + preopts */
212    xsnprintf(opts, sizeof(opts), "%s%s,%s=%d,%s,map=%s",
213	      preopts,
214	      MNTTAB_OPT_RW,
215	      MNTTAB_OPT_PORT, nfs_port,
216	      mf->mf_ops->fs_type, mf->mf_info);
217
218    /* process toplvl timeo/retrans options, if any */
219    if (gopt.amfs_auto_timeo[AMU_TYPE_TOPLVL] > 0) {
220      xsnprintf(toplvl_opts, sizeof(toplvl_opts), ",%s=%d",
221		MNTTAB_OPT_TIMEO, gopt.amfs_auto_timeo[AMU_TYPE_TOPLVL]);
222      xstrlcat(opts, toplvl_opts, sizeof(opts));
223    }
224    if (gopt.amfs_auto_retrans[AMU_TYPE_TOPLVL] > 0) {
225      xsnprintf(toplvl_opts, sizeof(toplvl_opts), ",%s=%d",
226		MNTTAB_OPT_RETRANS, gopt.amfs_auto_retrans[AMU_TYPE_TOPLVL]);
227      xstrlcat(opts, toplvl_opts, sizeof(opts));
228    }
229
230#ifdef MNTTAB_OPT_NOAC
231    if (gopt.auto_attrcache == 0) {
232      xstrlcat(opts, ",", sizeof(opts));
233      xstrlcat(opts, MNTTAB_OPT_NOAC, sizeof(opts));
234    } else
235#endif /* MNTTAB_OPT_NOAC */
236      set_auto_attrcache_timeout(preopts, opts, sizeof(preopts));
237  }
238
239  /* now do the mount */
240  error = amfs_mount(mp, mf, opts);
241  if (error) {
242    errno = error;
243    plog(XLOG_FATAL, "amfs_toplvl_mount: amfs_mount failed: %m");
244    return error;
245  }
246  return 0;
247}
248
249
250/*
251 * Unmount a top-level automount node
252 */
253int
254amfs_toplvl_umount(am_node *mp, mntfs *mf)
255{
256  struct stat stb;
257  int unmount_flags = (mf->mf_flags & MFF_ON_AUTOFS) ? AMU_UMOUNT_AUTOFS : 0;
258  int error;
259  int count = 0;		/* how many times did we try to unmount? */
260
261again:
262  /*
263   * The lstat is needed if this mount is type=direct.
264   * When that happens, the kernel cache gets confused
265   * between the underlying type (dir) and the mounted
266   * type (link) and so needs to be re-synced before
267   * the unmount.  This is all because the unmount system
268   * call follows links and so can't actually unmount
269   * a link (stupid!).  It was noted that doing an ls -ld
270   * of the mount point to see why things were not working
271   * actually fixed the problem - so simulate an ls -ld here.
272   */
273  if (lstat(mp->am_path, &stb) < 0) {
274    error = errno;
275    dlog("lstat(%s): %m", mp->am_path);
276    goto out;
277  }
278  if ((stb.st_mode & S_IFMT) != S_IFDIR) {
279    plog(XLOG_ERROR, "amfs_toplvl_umount: %s is not a directory, aborting.", mp->am_path);
280    error = ENOTDIR;
281    goto out;
282  }
283
284  error = UMOUNT_FS(mp->am_path, mnttab_file_name, unmount_flags);
285  if (error == EBUSY) {
286#ifdef HAVE_FS_AUTOFS
287    /*
288     * autofs mounts are "in place", so it is possible
289     * that we can't just unmount our mount points and go away.
290     * If that's the case, just give up.
291     */
292    if (mf->mf_flags & MFF_IS_AUTOFS)
293      return error;
294#endif /* HAVE_FS_AUTOFS */
295    plog(XLOG_WARNING, "amfs_toplvl_unmount retrying %s in 1s", mp->am_path);
296    count++;
297    sleep(1);
298    /*
299     * If user wants forced/lazy unmount semantics, then set those flags,
300     * but only after we've tried normal lstat/umount a few times --
301     * otherwise forced unmounts may hang this very same Amd (by preventing
302     * it from achieving a clean unmount).
303     */
304    if (gopt.flags & CFM_FORCED_UNMOUNTS) {
305      if (count == 5) {		/* after 5 seconds, try MNT_FORCE */
306	dlog("enabling forced unmounts for toplvl node %s", mp->am_path);
307	unmount_flags |= AMU_UMOUNT_FORCE;
308      }
309      if (count == 10) {	/* after 10 seconds, try MNT_DETACH */
310	dlog("enabling detached unmounts for toplvl node %s", mp->am_path);
311	unmount_flags |= AMU_UMOUNT_DETACH;
312      }
313    }
314    goto again;
315  }
316out:
317  return error;
318}
319