server/exports.c

   1 /* nbdkit
   2  * Copyright Red Hat
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  * * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *
  11  * * Redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution.
  14  *
  15  * * Neither the name of Red Hat nor the names of its contributors may be
  16  * used to endorse or promote products derived from this software without
  17  * specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  21  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  22  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
  23  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  26  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  27  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  29  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #include <config.h>
  34
  35 #include <stdlib.h>
  36 #include <stdbool.h>
  37 #include <string.h>
  38 #include <errno.h>
  39 #include <assert.h>
  40
  41 #include "vector.h"
  42
  43 #include "internal.h"
  44
  45 /* Cap nr_exports to avoid sending over-large replies to the client,
  46  * and to avoid a plugin with large list consuming too much memory.
  47  */
  48 #define MAX_EXPORTS 10000
  49
  50 /* Appendable list of exports. */
  51 DEFINE_VECTOR_TYPE (exports, struct nbdkit_export);
  52
  53 struct nbdkit_exports {
  54   exports exports;
  55   bool use_default;
  56 };
  57
  58 NBDKIT_DLL_PUBLIC struct nbdkit_exports *
  59 nbdkit_exports_new (void)
  60 {
  61   struct nbdkit_exports *r;
  62
  63   r = malloc (sizeof *r);
  64   if (r == NULL) {
  65     nbdkit_error ("nbdkit_exports_new: malloc: %m");
  66     return NULL;
  67   }
  68   r->exports = (exports) empty_vector;
  69   r->use_default = false;
  70   return r;
  71 }
  72
  73 static void
  74 nbdkit_export_clear (struct nbdkit_export exp)
  75 {
  76   free (exp.name);
  77   free (exp.description);
  78 }
  79
  80 NBDKIT_DLL_PUBLIC void
  81 nbdkit_exports_free (struct nbdkit_exports *exps)
  82 {
  83   if (exps) {
  84     exports_iter (&exps->exports, nbdkit_export_clear);
  85     free (exps->exports.ptr);
  86     free (exps);
  87   }
  88 }
  89
  90 NBDKIT_DLL_PUBLIC size_t
  91 nbdkit_exports_count (const struct nbdkit_exports *exps)
  92 {
  93   return exps->exports.len;
  94 }
  95
  96 NBDKIT_DLL_PUBLIC const struct nbdkit_export
  97 nbdkit_get_export (const struct nbdkit_exports *exps, size_t i)
  98 {
  99   assert (i < exps->exports.len);
 100   return exps->exports.ptr[i];
 101 }
 102
 103 NBDKIT_DLL_PUBLIC int
 104 nbdkit_add_export (struct nbdkit_exports *exps,
 105                    const char *name, const char *description)
 106 {
 107   struct nbdkit_export e = { NULL, NULL };
 108
 109   if (exps->exports.len == MAX_EXPORTS) {
 110     nbdkit_error ("nbdkit_add_export: too many exports");
 111     errno = EINVAL;
 112     return -1;
 113   }
 114   if (strlen (name) > NBD_MAX_STRING ||
 115       (description && strlen (description) > NBD_MAX_STRING)) {
 116     nbdkit_error ("nbdkit_add_export: string too long");
 117     errno = EINVAL;
 118     return -1;
 119   }
 120
 121   e.name = strdup (name);
 122   if (e.name == NULL) {
 123     nbdkit_error ("nbdkit_add_export: strdup: %m");
 124     return -1;
 125   }
 126   if (description) {
 127     e.description = strdup (description);
 128     if (e.description == NULL) {
 129       nbdkit_error ("nbdkit_add_export: strdup: %m");
 130       free (e.name);
 131       errno = ENOMEM;
 132       return -1;
 133     }
 134   }
 135
 136   if (exports_append (&exps->exports, e) == -1) {
 137     nbdkit_error ("nbdkit_add_export: realloc: %m");
 138     free (e.name);
 139     free (e.description);
 140     errno = ENOMEM;
 141     return -1;
 142   }
 143
 144   return 0;
 145 }
 146
 147 NBDKIT_DLL_PUBLIC int
 148 nbdkit_use_default_export (struct nbdkit_exports *exps)
 149 {
 150   exps->use_default = true;
 151   return 0;
 152 }
 153
 154 int
 155 exports_resolve_default (struct nbdkit_exports *exps, struct backend *b,
 156                          int readonly)
 157 {
 158   const char *def = NULL;
 159
 160   if (exps->use_default) {
 161     def = backend_default_export (b, readonly);
 162     exps->use_default = false;
 163   }
 164   if (def)
 165     return nbdkit_add_export (exps, def, NULL);
 166   return 0;
 167 }