lib/libzfs/os/linux/libzfs_util_os.c

   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 (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22
  23 #include <errno.h>
  24 #include <fcntl.h>
  25 #include <libintl.h>
  26 #include <stdarg.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <strings.h>
  30 #include <unistd.h>
  31 #include <math.h>
  32 #include <sys/stat.h>
  33 #include <sys/mnttab.h>
  34 #include <sys/mntent.h>
  35 #include <sys/types.h>
  36 #include <sys/wait.h>
  37
  38 #include <libzfs.h>
  39 #include <libzfs_core.h>
  40
  41 #include "../../libzfs_impl.h"
  42 #include "zfs_prop.h"
  43 #include <libzutil.h>
  44 #include <sys/zfs_sysfs.h>
  45
  46 #define ZDIFF_SHARESDIR         "/.zfs/shares/"
  47
  48 int
  49 zfs_ioctl(libzfs_handle_t *hdl, int request, zfs_cmd_t *zc)
  50 {
  51         return (ioctl(hdl->libzfs_fd, request, zc));
  52 }
  53
  54 const char *
  55 libzfs_error_init(int error)
  56 {
  57         switch (error) {
  58         case ENXIO:
  59                 return (dgettext(TEXT_DOMAIN, "The ZFS modules are not "
  60                     "loaded.\nTry running '/sbin/modprobe zfs' as root "
  61                     "to load them."));
  62         case ENOENT:
  63                 return (dgettext(TEXT_DOMAIN, "/dev/zfs and /proc/self/mounts "
  64                     "are required.\nTry running 'udevadm trigger' and 'mount "
  65                     "-t proc proc /proc' as root."));
  66         case ENOEXEC:
  67                 return (dgettext(TEXT_DOMAIN, "The ZFS modules cannot be "
  68                     "auto-loaded.\nTry running '/sbin/modprobe zfs' as "
  69                     "root to manually load them."));
  70         case EACCES:
  71                 return (dgettext(TEXT_DOMAIN, "Permission denied the "
  72                     "ZFS utilities must be run as root."));
  73         default:
  74                 return (dgettext(TEXT_DOMAIN, "Failed to initialize the "
  75                     "libzfs library."));
  76         }
  77 }
  78
  79 static int
  80 libzfs_module_loaded(const char *module)
  81 {
  82         const char path_prefix[] = "/sys/module/";
  83         char path[256];
  84
  85         memcpy(path, path_prefix, sizeof (path_prefix) - 1);
  86         strcpy(path + sizeof (path_prefix) - 1, module);
  87
  88         return (access(path, F_OK) == 0);
  89 }
  90
  91 /*
  92  * Verify the required ZFS_DEV device is available and optionally attempt
  93  * to load the ZFS modules.  Under normal circumstances the modules
  94  * should already have been loaded by some external mechanism.
  95  *
  96  * Environment variables:
  97  * - ZFS_MODULE_LOADING="YES|yes|ON|on" - Attempt to load modules.
  98  * - ZFS_MODULE_TIMEOUT="<seconds>"     - Seconds to wait for ZFS_DEV
  99  */
 100 static int
 101 libzfs_load_module_impl(const char *module)
 102 {
 103         char *argv[4] = {"/sbin/modprobe", "-q", (char *)module, (char *)0};
 104         char *load_str, *timeout_str;
 105         long timeout = 10; /* seconds */
 106         long busy_timeout = 10; /* milliseconds */
 107         int load = 0, fd;
 108         hrtime_t start;
 109
 110         /* Optionally request module loading */
 111         if (!libzfs_module_loaded(module)) {
 112                 load_str = getenv("ZFS_MODULE_LOADING");
 113                 if (load_str) {
 114                         if (!strncasecmp(load_str, "YES", strlen("YES")) ||
 115                             !strncasecmp(load_str, "ON", strlen("ON")))
 116                                 load = 1;
 117                         else
 118                                 load = 0;
 119                 }
 120
 121                 if (load) {
 122                         if (libzfs_run_process("/sbin/modprobe", argv, 0))
 123                                 return (ENOEXEC);
 124                 }
 125
 126                 if (!libzfs_module_loaded(module))
 127                         return (ENXIO);
 128         }
 129
 130         /*
 131          * Device creation by udev is asynchronous and waiting may be
 132          * required.  Busy wait for 10ms and then fall back to polling every
 133          * 10ms for the allowed timeout (default 10s, max 10m).  This is
 134          * done to optimize for the common case where the device is
 135          * immediately available and to avoid penalizing the possible
 136          * case where udev is slow or unable to create the device.
 137          */
 138         timeout_str = getenv("ZFS_MODULE_TIMEOUT");
 139         if (timeout_str) {
 140                 timeout = strtol(timeout_str, NULL, 0);
 141                 timeout = MAX(MIN(timeout, (10 * 60)), 0); /* 0 <= N <= 600 */
 142         }
 143
 144         start = gethrtime();
 145         do {
 146                 fd = open(ZFS_DEV, O_RDWR | O_CLOEXEC);
 147                 if (fd >= 0) {
 148                         (void) close(fd);
 149                         return (0);
 150                 } else if (errno != ENOENT) {
 151                         return (errno);
 152                 } else if (NSEC2MSEC(gethrtime() - start) < busy_timeout) {
 153                         sched_yield();
 154                 } else {
 155                         usleep(10 * MILLISEC);
 156                 }
 157         } while (NSEC2MSEC(gethrtime() - start) < (timeout * MILLISEC));
 158
 159         return (ENOENT);
 160 }
 161
 162 int
 163 libzfs_load_module(void)
 164 {
 165         return (libzfs_load_module_impl(ZFS_DRIVER));
 166 }
 167
 168 int
 169 find_shares_object(differ_info_t *di)
 170 {
 171         char fullpath[MAXPATHLEN];
 172         struct stat64 sb = { 0 };
 173
 174         (void) strlcpy(fullpath, di->dsmnt, MAXPATHLEN);
 175         (void) strlcat(fullpath, ZDIFF_SHARESDIR, MAXPATHLEN);
 176
 177         if (stat64(fullpath, &sb) != 0) {
 178                 (void) snprintf(di->errbuf, sizeof (di->errbuf),
 179                     dgettext(TEXT_DOMAIN, "Cannot stat %s"), fullpath);
 180                 return (zfs_error(di->zhp->zfs_hdl, EZFS_DIFF, di->errbuf));
 181         }
 182
 183         di->shares = (uint64_t)sb.st_ino;
 184         return (0);
 185 }
 186
 187 /*
 188  * Fill given version buffer with zfs kernel version read from ZFS_SYSFS_DIR
 189  * Returns 0 on success, and -1 on error (with errno set)
 190  */
 191 int
 192 zfs_version_kernel(char *version, int len)
 193 {
 194         int _errno;
 195         int fd;
 196         int rlen;
 197
 198         if ((fd = open(ZFS_SYSFS_DIR "/version", O_RDONLY | O_CLOEXEC)) == -1)
 199                 return (-1);
 200
 201         if ((rlen = read(fd, version, len)) == -1) {
 202                 version[0] = '\0';
 203                 _errno = errno;
 204                 (void) close(fd);
 205                 errno = _errno;
 206                 return (-1);
 207         }
 208
 209         version[rlen-1] = '\0';  /* discard '\n' */
 210
 211         if (close(fd) == -1)
 212                 return (-1);
 213
 214         return (0);
 215 }