libnl  1.1.4
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) 2003-2006 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  nl_errno(ENOMEM);
52  return NULL;
53  }
54 
55  new->ce_refcnt = 1;
56  nl_init_list_head(&new->ce_list);
57 
58  new->ce_ops = ops;
59  if (ops->oo_constructor)
60  ops->oo_constructor(new);
61 
62  NL_DBG(4, "Allocated new object %p\n", new);
63 
64  return new;
65 }
66 
67 /**
68  * Allocate a new object of kind specified by the name
69  * @arg kind name of object type
70  * @return The new object or nULL
71  */
72 struct nl_object *nl_object_alloc_name(const char *kind)
73 {
74  struct nl_cache_ops *ops;
75 
76  ops = nl_cache_ops_lookup(kind);
77  if (!ops) {
78  nl_error(ENOENT, "Unable to lookup cache kind \"%s\"", kind);
79  return NULL;
80  }
81 
82  return nl_object_alloc(ops->co_obj_ops);
83 }
84 
87  char data;
88 };
89 
90 /**
91  * Allocate a new object and copy all data from an existing object
92  * @arg obj object to inherite data from
93  * @return The new object or NULL.
94  */
95 struct nl_object *nl_object_clone(struct nl_object *obj)
96 {
97  struct nl_object *new;
98  struct nl_object_ops *ops = obj_ops(obj);
99  int doff = offsetof(struct nl_derived_object, data);
100  int size;
101 
102  new = nl_object_alloc(ops);
103  if (!new)
104  return NULL;
105 
106  size = ops->oo_size - doff;
107  if (size < 0)
108  BUG();
109 
110  new->ce_ops = obj->ce_ops;
111  new->ce_msgtype = obj->ce_msgtype;
112 
113  if (size)
114  memcpy((void *)new + doff, (void *)obj + doff, size);
115 
116  if (ops->oo_clone) {
117  if (ops->oo_clone(new, obj) < 0) {
118  nl_object_free(new);
119  return NULL;
120  }
121  } else if (size && ops->oo_free_data)
122  BUG();
123 
124  return new;
125 }
126 
127 /**
128  * Free a cacheable object
129  * @arg obj object to free
130  *
131  * @return 0 or a negative error code.
132  */
133 void nl_object_free(struct nl_object *obj)
134 {
135  struct nl_object_ops *ops;
136 
137  if (!obj)
138  return;
139 
140  ops = obj_ops(obj);
141 
142  if (obj->ce_refcnt > 0)
143  NL_DBG(1, "Warning: Freeing object in use...\n");
144 
145  if (obj->ce_cache)
146  nl_cache_remove(obj);
147 
148  if (ops->oo_free_data)
149  ops->oo_free_data(obj);
150 
151  free(obj);
152 
153  NL_DBG(4, "Freed object %p\n", obj);
154 }
155 
156 /** @} */
157 
158 /**
159  * @name Reference Management
160  * @{
161  */
162 
163 /**
164  * Acquire a reference on a object
165  * @arg obj object to acquire reference from
166  */
167 void nl_object_get(struct nl_object *obj)
168 {
169  obj->ce_refcnt++;
170  NL_DBG(4, "New reference to object %p, total %d\n",
171  obj, obj->ce_refcnt);
172 }
173 
174 /**
175  * Release a reference from an object
176  * @arg obj object to release reference from
177  */
178 void nl_object_put(struct nl_object *obj)
179 {
180  if (!obj)
181  return;
182 
183  obj->ce_refcnt--;
184  NL_DBG(4, "Returned object reference %p, %d remaining\n",
185  obj, obj->ce_refcnt);
186 
187  if (obj->ce_refcnt < 0)
188  BUG();
189 
190  if (obj->ce_refcnt <= 0)
191  nl_object_free(obj);
192 }
193 
194 /**
195  * Check whether this object is used by multiple users
196  * @arg obj object to check
197  * @return true or false
198  */
199 int nl_object_shared(struct nl_object *obj)
200 {
201  return obj->ce_refcnt > 1;
202 }
203 
204 /** @} */
205 
206 /**
207  * @name Marks
208  * @{
209  */
210 
211 /**
212  * Add mark to object
213  * @arg obj Object to mark
214  */
215 void nl_object_mark(struct nl_object *obj)
216 {
217  obj->ce_flags |= NL_OBJ_MARK;
218 }
219 
220 /**
221  * Remove mark from object
222  * @arg obj Object to unmark
223  */
224 void nl_object_unmark(struct nl_object *obj)
225 {
226  obj->ce_flags &= ~NL_OBJ_MARK;
227 }
228 
229 /**
230  * Return true if object is marked
231  * @arg obj Object to check
232  * @return true if object is marked, otherwise false
233  */
234 int nl_object_is_marked(struct nl_object *obj)
235 {
236  return (obj->ce_flags & NL_OBJ_MARK);
237 }
238 
239 /** @} */
240 
241 /**
242  * @name Utillities
243  * @{
244  */
245 
246 /**
247  * Dump this object according to the specified parameters
248  * @arg obj object to dump
249  * @arg params dumping parameters
250  */
251 void nl_object_dump(struct nl_object *obj, struct nl_dump_params *params)
252 {
253  dump_from_ops(obj, params);
254 }
255 
256 /**
257  * Check if the identifiers of two objects are identical
258  * @arg a an object
259  * @arg b another object of same type
260  *
261  * @return true if both objects have equal identifiers, otherwise false.
262  */
263 int nl_object_identical(struct nl_object *a, struct nl_object *b)
264 {
265  struct nl_object_ops *ops = obj_ops(a);
266  int req_attrs;
267 
268  /* Both objects must be of same type */
269  if (ops != obj_ops(b))
270  return 0;
271 
272  req_attrs = ops->oo_id_attrs;
273 
274  /* Both objects must provide all required attributes to uniquely
275  * identify an object */
276  if ((a->ce_mask & req_attrs) != req_attrs ||
277  (b->ce_mask & req_attrs) != req_attrs)
278  return 0;
279 
280  /* Can't judge unless we can compare */
281  if (ops->oo_compare == NULL)
282  return 0;
283 
284  return !(ops->oo_compare(a, b, req_attrs, 0));
285 }
286 
287 /**
288  * Compute bitmask representing difference in attribute values
289  * @arg a an object
290  * @arg b another object of same type
291  *
292  * The bitmask returned is specific to an object type, each bit set represents
293  * an attribute which mismatches in either of the two objects. Unavailability
294  * of an attribute in one object and presence in the other is regarded a
295  * mismatch as well.
296  *
297  * @return Bitmask describing differences or 0 if they are completely identical.
298  */
299 uint32_t nl_object_diff(struct nl_object *a, struct nl_object *b)
300 {
301  struct nl_object_ops *ops = obj_ops(a);
302 
303  if (ops != obj_ops(b) || ops->oo_compare == NULL)
304  return UINT_MAX;
305 
306  return ops->oo_compare(a, b, ~0, 0);
307 }
308 
309 /**
310  * Match a filter against an object
311  * @arg obj object to check
312  * @arg filter object of same type acting as filter
313  *
314  * @return 1 if the object matches the filter or 0
315  * if no filter procedure is available or if the
316  * filter does not match.
317  */
318 int nl_object_match_filter(struct nl_object *obj, struct nl_object *filter)
319 {
320  struct nl_object_ops *ops = obj_ops(obj);
321 
322  if (ops != obj_ops(filter) || ops->oo_compare == NULL)
323  return 0;
324 
325  return !(ops->oo_compare(obj, filter, filter->ce_mask,
326  LOOSE_FLAG_COMPARISON));
327 }
328 
329 /**
330  * Convert bitmask of attributes to a character string
331  * @arg obj object of same type as attribute bitmask
332  * @arg attrs bitmask of attribute types
333  * @arg buf destination buffer
334  * @arg len length of destination buffer
335  *
336  * Converts the bitmask of attribute types into a list of attribute
337  * names separated by comas.
338  *
339  * @return destination buffer.
340  */
341 char *nl_object_attrs2str(struct nl_object *obj, uint32_t attrs,
342  char *buf, size_t len)
343 {
344  struct nl_object_ops *ops = obj_ops(obj);
345 
346  if (ops->oo_attrs2str != NULL)
347  return ops->oo_attrs2str(attrs, buf, len);
348  else {
349  memset(buf, 0, len);
350  return buf;
351  }
352 }
353 
354 /**
355  * Return list of attributes present in an object
356  * @arg obj an object
357  * @arg buf destination buffer
358  * @arg len length of destination buffer
359  *
360  * @return destination buffer.
361  */
362 char *nl_object_attr_list(struct nl_object *obj, char *buf, size_t len)
363 {
364  return nl_object_attrs2str(obj, obj->ce_mask, buf, len);
365 }
366 
367 /** @} */
368 
369 /**
370  * @name Attributes
371  * @{
372  */
373 
374 int nl_object_get_refcnt(struct nl_object *obj)
375 {
376  return obj->ce_refcnt;
377 }
378 
379 struct nl_cache *nl_object_get_cache(struct nl_object *obj)
380 {
381  return obj->ce_cache;
382 }
383 
384 /** @} */
385 
386 /** @} */