package/libnl-tiny/src/object.c

   1 /*
   2  * lib/object.c         Generic Cacheable Object
   3  *
   4  *      This library is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU Lesser General Public
   6  *      License as published by the Free Software Foundation version 2.1
   7  *      of the License.
   8  *
   9  * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
  10  */
  11
  12 /**
  13  * @ingroup cache
  14  * @defgroup object Object
  15  * @{
  16  */
  17
  18 #include <netlink-local.h>
  19 #include <netlink/netlink.h>
  20 #include <netlink/cache.h>
  21 #include <netlink/object.h>
  22 #include <netlink/utils.h>
  23
  24 static inline struct nl_object_ops *obj_ops(struct nl_object *obj)
  25 {
  26         if (!obj->ce_ops)
  27                 BUG();
  28
  29         return obj->ce_ops;
  30 }
  31
  32 /**
  33  * @name Object Creation/Deletion
  34  * @{
  35  */
  36
  37 /**
  38  * Allocate a new object of kind specified by the operations handle
  39  * @arg ops             cache operations handle
  40  * @return The new object or NULL
  41  */
  42 struct nl_object *nl_object_alloc(struct nl_object_ops *ops)
  43 {
  44         struct nl_object *new;
  45
  46         if (ops->oo_size < sizeof(*new))
  47                 BUG();
  48
  49         new = calloc(1, ops->oo_size);
  50         if (!new)
  51                 return NULL;
  52
  53         new->ce_refcnt = 1;
  54         nl_init_list_head(&new->ce_list);
  55
  56         new->ce_ops = ops;
  57         if (ops->oo_constructor)
  58                 ops->oo_constructor(new);
  59
  60         NL_DBG(4, "Allocated new object %p\n", new);
  61
  62         return new;
  63 }
  64
  65 #ifdef disabled
  66 /**
  67  * Allocate a new object of kind specified by the name
  68  * @arg kind            name of object type
  69  * @return The new object or nULL
  70  */
  71 int nl_object_alloc_name(const char *kind, struct nl_object **result)
  72 {
  73         struct nl_cache_ops *ops;
  74
  75         ops = nl_cache_ops_lookup(kind);
  76         if (!ops)
  77                 return -NLE_OPNOTSUPP;
  78
  79         if (!(*result = nl_object_alloc(ops->co_obj_ops)))
  80                 return -NLE_NOMEM;
  81
  82         return 0;
  83 }
  84 #endif
  85
  86 struct nl_derived_object {
  87         NLHDR_COMMON
  88         char data;
  89 };
  90
  91 /**
  92  * Allocate a new object and copy all data from an existing object
  93  * @arg obj             object to inherite data from
  94  * @return The new object or NULL.
  95  */
  96 struct nl_object *nl_object_clone(struct nl_object *obj)
  97 {
  98         struct nl_object *new;
  99         struct nl_object_ops *ops = obj_ops(obj);
 100         int doff = offsetof(struct nl_derived_object, data);
 101         int size;
 102
 103         new = nl_object_alloc(ops);
 104         if (!new)
 105                 return NULL;
 106
 107         size = ops->oo_size - doff;
 108         if (size < 0)
 109                 BUG();
 110
 111         new->ce_ops = obj->ce_ops;
 112         new->ce_msgtype = obj->ce_msgtype;
 113
 114         if (size)
 115                 memcpy((void *)new + doff, (void *)obj + doff, size);
 116
 117         if (ops->oo_clone) {
 118                 if (ops->oo_clone(new, obj) < 0) {
 119                         nl_object_free(new);
 120                         return NULL;
 121                 }
 122         } else if (size && ops->oo_free_data)
 123                 BUG();
 124
 125         return new;
 126 }
 127
 128 /**
 129  * Free a cacheable object
 130  * @arg obj             object to free
 131  *
 132  * @return 0 or a negative error code.
 133  */
 134 void nl_object_free(struct nl_object *obj)
 135 {
 136         struct nl_object_ops *ops = obj_ops(obj);
 137
 138         if (obj->ce_refcnt > 0)
 139                 NL_DBG(1, "Warning: Freeing object in use...\n");
 140
 141         if (obj->ce_cache)
 142                 nl_cache_remove(obj);
 143
 144         if (ops->oo_free_data)
 145                 ops->oo_free_data(obj);
 146
 147         free(obj);
 148
 149         NL_DBG(4, "Freed object %p\n", obj);
 150 }
 151
 152 /** @} */
 153
 154 /**
 155  * @name Reference Management
 156  * @{
 157  */
 158
 159 /**
 160  * Acquire a reference on a object
 161  * @arg obj             object to acquire reference from
 162  */
 163 void nl_object_get(struct nl_object *obj)
 164 {
 165         obj->ce_refcnt++;
 166         NL_DBG(4, "New reference to object %p, total %d\n",
 167                obj, obj->ce_refcnt);
 168 }
 169
 170 /**
 171  * Release a reference from an object
 172  * @arg obj             object to release reference from
 173  */
 174 void nl_object_put(struct nl_object *obj)
 175 {
 176         if (!obj)
 177                 return;
 178
 179         obj->ce_refcnt--;
 180         NL_DBG(4, "Returned object reference %p, %d remaining\n",
 181                obj, obj->ce_refcnt);
 182
 183         if (obj->ce_refcnt < 0)
 184                 BUG();
 185
 186         if (obj->ce_refcnt <= 0)
 187                 nl_object_free(obj);
 188 }
 189
 190 /** @} */
 191
 192 /**
 193  * @name Utillities
 194  * @{
 195  */
 196
 197 #ifdef disabled
 198 /**
 199  * Dump this object according to the specified parameters
 200  * @arg obj             object to dump
 201  * @arg params          dumping parameters
 202  */
 203 void nl_object_dump(struct nl_object *obj, struct nl_dump_params *params)
 204 {
 205         dump_from_ops(obj, params);
 206 }
 207
 208 /**
 209  * Check if the identifiers of two objects are identical
 210  * @arg a               an object
 211  * @arg b               another object of same type
 212  *
 213  * @return true if both objects have equal identifiers, otherwise false.
 214  */
 215 int nl_object_identical(struct nl_object *a, struct nl_object *b)
 216 {
 217         struct nl_object_ops *ops = obj_ops(a);
 218         int req_attrs;
 219
 220         /* Both objects must be of same type */
 221         if (ops != obj_ops(b))
 222                 return 0;
 223
 224         req_attrs = ops->oo_id_attrs;
 225
 226         /* Both objects must provide all required attributes to uniquely
 227          * identify an object */
 228         if ((a->ce_mask & req_attrs) != req_attrs ||
 229             (b->ce_mask & req_attrs) != req_attrs)
 230                 return 0;
 231
 232         /* Can't judge unless we can compare */
 233         if (ops->oo_compare == NULL)
 234                 return 0;
 235
 236         return !(ops->oo_compare(a, b, req_attrs, 0));
 237 }
 238 #endif
 239
 240 /**
 241  * Compute bitmask representing difference in attribute values
 242  * @arg a               an object
 243  * @arg b               another object of same type
 244  *
 245  * The bitmask returned is specific to an object type, each bit set represents
 246  * an attribute which mismatches in either of the two objects. Unavailability
 247  * of an attribute in one object and presence in the other is regarded a
 248  * mismatch as well.
 249  *
 250  * @return Bitmask describing differences or 0 if they are completely identical.
 251  */
 252 uint32_t nl_object_diff(struct nl_object *a, struct nl_object *b)
 253 {
 254         struct nl_object_ops *ops = obj_ops(a);
 255
 256         if (ops != obj_ops(b) || ops->oo_compare == NULL)
 257                 return UINT_MAX;
 258
 259         return ops->oo_compare(a, b, ~0, 0);
 260 }
 261
 262 /**
 263  * Match a filter against an object
 264  * @arg obj             object to check
 265  * @arg filter          object of same type acting as filter
 266  *
 267  * @return 1 if the object matches the filter or 0
 268  *           if no filter procedure is available or if the
 269  *           filter does not match.
 270  */
 271 int nl_object_match_filter(struct nl_object *obj, struct nl_object *filter)
 272 {
 273         struct nl_object_ops *ops = obj_ops(obj);
 274
 275         if (ops != obj_ops(filter) || ops->oo_compare == NULL)
 276                 return 0;
 277
 278         return !(ops->oo_compare(obj, filter, filter->ce_mask,
 279                                  LOOSE_COMPARISON));
 280 }
 281
 282 /**
 283  * Convert bitmask of attributes to a character string
 284  * @arg obj             object of same type as attribute bitmask
 285  * @arg attrs           bitmask of attribute types
 286  * @arg buf             destination buffer
 287  * @arg len             length of destination buffer
 288  *
 289  * Converts the bitmask of attribute types into a list of attribute
 290  * names separated by comas.
 291  *
 292  * @return destination buffer.
 293  */
 294 char *nl_object_attrs2str(struct nl_object *obj, uint32_t attrs,
 295                           char *buf, size_t len)
 296 {
 297         struct nl_object_ops *ops = obj_ops(obj);
 298
 299         if (ops->oo_attrs2str != NULL)
 300                 return ops->oo_attrs2str(attrs, buf, len);
 301         else {
 302                 memset(buf, 0, len);
 303                 return buf;
 304         }
 305 }
 306
 307 /** @} */
 308
 309 /** @} */