external/cddl/osnet/lib/libzfs/fsshare.c

   1 /*      $NetBSD: fsshare.c,v 1.1 2009/08/07 20:57:56 haad Exp $ */
   2
   3 /*-
   4  * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 /* __FBSDID("$FreeBSD: src/compat/opensolaris/misc/fsshare.c,v 1.2 2007/04/21 13:17:23 pjd Exp $"); */
  31 __RCSID("$NetBSD: fsshare.c,v 1.1 2009/08/07 20:57:56 haad Exp $");
  32
  33 #include <sys/param.h>
  34 #include <stdio.h>
  35 #include <unistd.h>
  36 #include <fcntl.h>
  37 #include <signal.h>
  38 #include <string.h>
  39 #include <stdlib.h>
  40 #include <errno.h>
  41 #include <assert.h>
  42 #include <pathnames.h>  /* _PATH_MOUNTDPID */
  43 #include <fsshare.h>
  44
  45 #define FILE_HEADER     "# !!! DO NOT EDIT THIS FILE MANUALLY !!!\n\n"
  46 #define OPTSSIZE        1024
  47 #define MAXLINESIZE     (PATH_MAX + OPTSSIZE)
  48
  49 static void
  50 restart_mountd(void)
  51 {
  52         int pid;
  53         FILE *pfh;
  54
  55         pfh = fopen(_PATH_MOUNTDPID, "r");
  56         if (pfh == NULL)
  57                 return;
  58         fscanf(pfh, "%d", &pid);
  59         fclose(pfh);
  60         kill((pid_t)pid, SIGHUP);
  61 }
  62
  63 /*
  64  * Read one line from a file. Skip comments, empty lines and a line with a
  65  * mountpoint specified in the 'skip' argument.
  66  */
  67 static char *
  68 zgetline(FILE *fd, const char *skip)
  69 {
  70         static char line[MAXLINESIZE];
  71         size_t len, skiplen;
  72         char *s, last;
  73
  74         if (skip != NULL)
  75                 skiplen = strlen(skip);
  76         for (;;) {
  77                 s = fgets(line, sizeof(line), fd);
  78                 if (s == NULL)
  79                         return (NULL);
  80                 /* Skip empty lines and comments. */
  81                 if (line[0] == '\n' || line[0] == '#')
  82                         continue;
  83                 len = strlen(line);
  84                 if (line[len - 1] == '\n')
  85                         line[len - 1] = '\0';
  86                 last = line[skiplen];
  87                 /* Skip the given mountpoint. */
  88                 if (skip != NULL && strncmp(skip, line, skiplen) == 0 &&
  89                     (last == '\t' || last == ' ' || last == '\0')) {
  90                         continue;
  91                 }
  92                 break;
  93         }
  94         return (line);
  95 }
  96
  97 /*
  98  * Function translate options to a format acceptable by exports(5), eg.
  99  *
 100  *      -ro -network=192.168.0.0 -mask=255.255.255.0 -maproot=0 freefall.freebsd.org 69.147.83.54
 101  *
 102  * Accepted input formats:
 103  *
 104  *      ro,network=192.168.0.0,mask=255.255.255.0,maproot=0,freefall.freebsd.org
 105  *      ro network=192.168.0.0 mask=255.255.255.0 maproot=0 freefall.freebsd.org
 106  *      -ro,-network=192.168.0.0,-mask=255.255.255.0,-maproot=0,freefall.freebsd.org
 107  *      -ro -network=192.168.0.0 -mask=255.255.255.0 -maproot=0 freefall.freebsd.org
 108  *
 109  * Recognized keywords:
 110  *
 111  *      ro, maproot, mapall, mask, network, alldirs, public, webnfs, index, quiet
 112  *
 113  */
 114 static const char *known_opts[] = { "ro", "maproot", "mapall", "mask",
 115     "network", "alldirs", "public", "webnfs", "index", "quiet", NULL };
 116 static char *
 117 translate_opts(const char *shareopts)
 118 {
 119         static char newopts[OPTSSIZE];
 120         char oldopts[OPTSSIZE];
 121         char *o, *s = NULL;
 122         unsigned int i;
 123         size_t len;
 124
 125         strlcpy(oldopts, shareopts, sizeof(oldopts));
 126         newopts[0] = '\0';
 127         s = oldopts;
 128         while ((o = strsep(&s, "-, ")) != NULL) {
 129                 if (o[0] == '\0')
 130                         continue;
 131                 for (i = 0; known_opts[i] != NULL; i++) {
 132                         len = strlen(known_opts[i]);
 133                         if (strncmp(known_opts[i], o, len) == 0 &&
 134                             (o[len] == '\0' || o[len] == '=')) {
 135                                 strlcat(newopts, "-", sizeof(newopts));
 136                                 break;
 137                         }
 138                 }
 139                 strlcat(newopts, o, sizeof(newopts));
 140                 strlcat(newopts, " ", sizeof(newopts));
 141         }
 142         return (newopts);
 143 }
 144
 145 static int
 146 fsshare_main(const char *file, const char *mountpoint, const char *shareopts,
 147     int share)
 148 {
 149         char tmpfile[PATH_MAX];
 150         char *line;
 151         FILE *newfd, *oldfd;
 152         int fd, error;
 153
 154         newfd = oldfd = NULL;
 155         error = 0;
 156
 157         /*
 158          * Create temporary file in the same directory, so we can atomically
 159          * rename it.
 160          */
 161         if (strlcpy(tmpfile, file, sizeof(tmpfile)) >= sizeof(tmpfile))
 162                 return (ENAMETOOLONG);
 163         if (strlcat(tmpfile, ".XXXXXXXX", sizeof(tmpfile)) >= sizeof(tmpfile))
 164                 return (ENAMETOOLONG);
 165         fd = mkstemp(tmpfile);
 166         if (fd == -1)
 167                 return (errno);
 168         /*
 169          * File name is random, so we don't really need file lock now, but it
 170          * will be needed after rename(2).
 171          */
 172         error = flock(fd, LOCK_EX);
 173         assert(error == 0 || (error == -1 && errno == EOPNOTSUPP));
 174         newfd = fdopen(fd, "r+");
 175         assert(newfd != NULL);
 176         /* Open old exports file. */
 177         oldfd = fopen(file, "r");
 178         if (oldfd == NULL) {
 179                 if (share) {
 180                         if (errno != ENOENT) {
 181                                 error = errno;
 182                                 goto out;
 183                         }
 184                 } else {
 185                         /* If there is no exports file, ignore the error. */
 186                         if (errno == ENOENT)
 187                                 errno = 0;
 188                         error = errno;
 189                         goto out;
 190                 }
 191         } else {
 192                 error = flock(fileno(oldfd), LOCK_EX);
 193                 assert(error == 0 || (error == -1 && errno == EOPNOTSUPP));
 194                 error = 0;
 195         }
 196
 197         /* Place big, fat warning at the begining of the file. */
 198         fprintf(newfd, "%s", FILE_HEADER);
 199         while (oldfd != NULL && (line = zgetline(oldfd, mountpoint)) != NULL)
 200                 fprintf(newfd, "%s\n", line);
 201         if (oldfd != NULL && ferror(oldfd) != 0) {
 202                 error = ferror(oldfd);
 203                 goto out;
 204         }
 205         if (ferror(newfd) != 0) {
 206                 error = ferror(newfd);
 207                 goto out;
 208         }
 209         if (share) {
 210                 fprintf(newfd, "%s\t%s\n", mountpoint,
 211                     translate_opts(shareopts));
 212         }
 213
 214 out:
 215         if (error != 0)
 216                 unlink(tmpfile);
 217         else {
 218                 if (rename(tmpfile, file) == -1) {
 219                         error = errno;
 220                         unlink(tmpfile);
 221                 } else {
 222                         /*
 223                          * Send SIGHUP to mountd, but unlock exports file later.
 224                          */
 225                         restart_mountd();
 226                 }
 227         }
 228         if (oldfd != NULL) {
 229                 flock(fileno(oldfd), LOCK_UN);
 230                 fclose(oldfd);
 231         }
 232         if (newfd != NULL) {
 233                 flock(fileno(newfd), LOCK_UN);
 234                 fclose(newfd);
 235         }
 236         return (error);
 237 }
 238
 239 /*
 240  * Add the given mountpoint to the given exports file.
 241  */
 242 int
 243 fsshare(const char *file, const char *mountpoint, const char *shareopts)
 244 {
 245
 246         return (fsshare_main(file, mountpoint, shareopts, 1));
 247 }
 248
 249 /*
 250  * Remove the given mountpoint from the given exports file.
 251  */
 252 int
 253 fsunshare(const char *file, const char *mountpoint)
 254 {
 255
 256         return (fsshare_main(file, mountpoint, NULL, 0));
 257 }