g13/mountinfo.c

   1 /* mountinfo.c - Track infos about mounts
   2  * Copyright (C) 2009 Free Software Foundation, Inc.
   3  *
   4  * This file is part of GnuPG.
   5  *
   6  * GnuPG is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * GnuPG is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <sys/stat.h>
  27 #include <assert.h>
  28
  29 #include "g13.h"
  30 #include "i18n.h"
  31 #include "mountinfo.h"
  32
  33 #include "keyblob.h"
  34 #include "utils.h"
  35
  36
  37
  38 /* The object to keep track of mount information.  */
  39 struct mounttable_s
  40 {
  41   int in_use;        /* The slot is in use.  */
  42   char *container;   /* Name of the container.  */
  43   char *mountpoint;  /* Name of the mounttype.  */
  44   int conttype;      /* Type of the container.  */
  45   unsigned int rid;  /* Identifier of the runner task.  */
  46   struct {
  47     unsigned int remove:1;  /* True if the mountpoint shall be removed
  48                                on umount.  */
  49   } flags;
  50 };
  51
  52
  53 /* The allocated table of mounts and its size.  */
  54 static mtab_t mounttable;
  55 size_t mounttable_size;
  56
  57
  58 \f
  59 /* Add CONTAINER,MOUNTPOINT,CONTTYPE,RID to the mounttable.  */
  60 gpg_error_t
  61 mountinfo_add_mount (const char *container, const char *mountpoint,
  62                      int conttype, unsigned int rid, int remove_flag)
  63 {
  64   size_t idx;
  65   mtab_t m;
  66
  67   for (idx=0; idx < mounttable_size; idx++)
  68     if (!mounttable[idx].in_use)
  69       break;
  70   if (!(idx < mounttable_size))
  71     {
  72       size_t nslots = mounttable_size;
  73
  74       mounttable_size += 10;
  75       m = xtrycalloc (mounttable_size, sizeof *mounttable);
  76       if (!m)
  77         return gpg_error_from_syserror ();
  78       if (mounttable)
  79         {
  80           for (idx=0; idx < nslots; idx++)
  81             m[idx] = mounttable[idx];
  82           xfree (mounttable);
  83         }
  84       mounttable = m;
  85       m = mounttable + nslots;
  86       assert (!m->in_use);
  87     }
  88   else
  89     m = mounttable + idx;
  90
  91   m->container = xtrystrdup (container);
  92   if (!m->container)
  93     return gpg_error_from_syserror ();
  94   m->mountpoint = xtrystrdup (mountpoint);
  95   if (!m->mountpoint)
  96     {
  97       xfree (m->container);
  98       m->container = NULL;
  99       return gpg_error_from_syserror ();
 100     }
 101   m->conttype = conttype;
 102   m->rid = rid;
 103   m->flags.remove = !!remove_flag;
 104   m->in_use = 1;
 105
 106   return 0;
 107 }
 108
 109
 110 /* Remove a mount info.  Either the CONTAINER, the MOUNTPOINT or the
 111    RID must be given.  The first argument given is used.  */
 112 gpg_error_t
 113 mountinfo_del_mount (const char *container, const char *mountpoint,
 114                      unsigned int rid)
 115 {
 116   gpg_error_t err;
 117   size_t idx;
 118   mtab_t m;
 119
 120   /* If a container or mountpint is givem search the RID via the
 121      standard find fucntion.  */
 122   if (container || mountpoint)
 123     {
 124       err = mountinfo_find_mount (container, mountpoint, &rid);
 125       if (err)
 126         return err;
 127     }
 128
 129   /* Find via RID and delete. */
 130   for (idx=0, m = mounttable; idx < mounttable_size; idx++, m++)
 131     if (m->in_use && m->rid == rid)
 132       {
 133         if (m->flags.remove && m->mountpoint)
 134           {
 135             /* FIXME: This does not always work because the umount may
 136                not have completed yet.  We should add the mountpoints
 137                to an idle queue and retry a remove.  */
 138             if (rmdir (m->mountpoint))
 139               log_error ("error removing mount point `%s': %s\n",
 140                          m->mountpoint,
 141                          gpg_strerror (gpg_error_from_syserror ()));
 142           }
 143         m->in_use = 0;
 144         xfree (m->container);
 145         m->container = NULL;
 146         xfree (m->mountpoint);
 147         m->mountpoint = NULL;
 148         return 0;
 149       }
 150   return gpg_error (GPG_ERR_NOT_FOUND);
 151 }
 152
 153
 154 /* Find a mount and return its rid at R_RID.  If CONTAINER is given,
 155    the search is done by the container name, if it is not given the
 156    search is done by MOUNTPOINT.  */
 157 gpg_error_t
 158 mountinfo_find_mount (const char *container, const char *mountpoint,
 159                       unsigned int *r_rid)
 160 {
 161   size_t idx;
 162   mtab_t m;
 163
 164   if (container)
 165     {
 166       for (idx=0, m = mounttable; idx < mounttable_size; idx++, m++)
 167         if (m->in_use && !strcmp (m->container, container))
 168           break;
 169     }
 170   else if (mountpoint)
 171     {
 172       for (idx=0, m = mounttable; idx < mounttable_size; idx++, m++)
 173         if (m->in_use && !strcmp (m->mountpoint, mountpoint))
 174           break;
 175     }
 176   else
 177     idx = mounttable_size;
 178   if (!(idx < mounttable_size))
 179     return gpg_error (GPG_ERR_NOT_FOUND);
 180
 181   *r_rid = m->rid;
 182   return 0;
 183 }
 184
 185
 186 /* Dump all info to the log stream.  */
 187 void
 188 mountinfo_dump_all (void)
 189 {
 190   size_t idx;
 191   mtab_t m;
 192
 193   for (idx=0, m = mounttable; idx < mounttable_size; idx++, m++)
 194     if (m->in_use)
 195       log_info ("mtab[%d] %s on %s type %d rid %u%s\n",
 196                 idx, m->container, m->mountpoint, m->conttype, m->rid,
 197                 m->flags.remove?" [remove]":"");
 198 }
 199