1/*
2 * Copyright © 2010 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 */
23
24#include <assert.h>
25#include <stdlib.h>
26#include <stdarg.h>
27#include <stdio.h>
28#include <string.h>
29#include <stdint.h>
30
31/* Android defines SIZE_MAX in limits.h, instead of the standard stdint.h */
32#ifdef ANDROID
33#include <limits.h>
34#endif
35
36/* Some versions of MinGW are missing _vscprintf's declaration, although they
37 * still provide the symbol in the import library. */
38#ifdef __MINGW32__
39_CRTIMP int _vscprintf(const char *format, va_list argptr);
40#endif
41
42#include "ralloc.h"
43
44#ifndef va_copy
45#ifdef __va_copy
46#define va_copy(dest, src) __va_copy((dest), (src))
47#else
48#define va_copy(dest, src) (dest) = (src)
49#endif
50#endif
51
52#define CANARY 0x5A1106
53
54struct ralloc_header
55{
56   /* A canary value used to determine whether a pointer is ralloc'd. */
57   unsigned canary;
58
59   struct ralloc_header *parent;
60
61   /* The first child (head of a linked list) */
62   struct ralloc_header *child;
63
64   /* Linked list of siblings */
65   struct ralloc_header *prev;
66   struct ralloc_header *next;
67
68   void (*destructor)(void *);
69};
70
71typedef struct ralloc_header ralloc_header;
72
73static void unlink_block(ralloc_header *info);
74static void unsafe_free(ralloc_header *info);
75
76static ralloc_header *
77get_header(const void *ptr)
78{
79   ralloc_header *info = (ralloc_header *) (((char *) ptr) -
80					    sizeof(ralloc_header));
81   assert(info->canary == CANARY);
82   return info;
83}
84
85#define PTR_FROM_HEADER(info) (((char *) info) + sizeof(ralloc_header))
86
87static void
88add_child(ralloc_header *parent, ralloc_header *info)
89{
90   if (parent != NULL) {
91      info->parent = parent;
92      info->next = parent->child;
93      parent->child = info;
94
95      if (info->next != NULL)
96	 info->next->prev = info;
97   }
98}
99
100void *
101ralloc_context(const void *ctx)
102{
103   return ralloc_size(ctx, 0);
104}
105
106void *
107ralloc_size(const void *ctx, size_t size)
108{
109   void *block = calloc(1, size + sizeof(ralloc_header));
110
111   ralloc_header *info = (ralloc_header *) block;
112   ralloc_header *parent = ctx != NULL ? get_header(ctx) : NULL;
113
114   add_child(parent, info);
115
116   info->canary = CANARY;
117
118   return PTR_FROM_HEADER(info);
119}
120
121void *
122rzalloc_size(const void *ctx, size_t size)
123{
124   void *ptr = ralloc_size(ctx, size);
125   if (likely(ptr != NULL))
126      memset(ptr, 0, size);
127   return ptr;
128}
129
130/* helper function - assumes ptr != NULL */
131static void *
132resize(void *ptr, size_t size)
133{
134   ralloc_header *child, *old, *info;
135
136   old = get_header(ptr);
137   info = realloc(old, size + sizeof(ralloc_header));
138
139   if (info == NULL)
140      return NULL;
141
142   /* Update parent and sibling's links to the reallocated node. */
143   if (info != old && info->parent != NULL) {
144      if (info->parent->child == old)
145	 info->parent->child = info;
146
147      if (info->prev != NULL)
148	 info->prev->next = info;
149
150      if (info->next != NULL)
151	 info->next->prev = info;
152   }
153
154   /* Update child->parent links for all children */
155   for (child = info->child; child != NULL; child = child->next)
156      child->parent = info;
157
158   return PTR_FROM_HEADER(info);
159}
160
161void *
162reralloc_size(const void *ctx, void *ptr, size_t size)
163{
164   if (unlikely(ptr == NULL))
165      return ralloc_size(ctx, size);
166
167   assert(ralloc_parent(ptr) == ctx);
168   return resize(ptr, size);
169}
170
171void *
172ralloc_array_size(const void *ctx, size_t size, unsigned count)
173{
174   if (count > SIZE_MAX/size)
175      return NULL;
176
177   return ralloc_size(ctx, size * count);
178}
179
180void *
181rzalloc_array_size(const void *ctx, size_t size, unsigned count)
182{
183   if (count > SIZE_MAX/size)
184      return NULL;
185
186   return rzalloc_size(ctx, size * count);
187}
188
189void *
190reralloc_array_size(const void *ctx, void *ptr, size_t size, unsigned count)
191{
192   if (count > SIZE_MAX/size)
193      return NULL;
194
195   return reralloc_size(ctx, ptr, size * count);
196}
197
198void
199ralloc_free(void *ptr)
200{
201   ralloc_header *info;
202
203   if (ptr == NULL)
204      return;
205
206   info = get_header(ptr);
207   unlink_block(info);
208   unsafe_free(info);
209}
210
211static void
212unlink_block(ralloc_header *info)
213{
214   /* Unlink from parent & siblings */
215   if (info->parent != NULL) {
216      if (info->parent->child == info)
217	 info->parent->child = info->next;
218
219      if (info->prev != NULL)
220	 info->prev->next = info->next;
221
222      if (info->next != NULL)
223	 info->next->prev = info->prev;
224   }
225   info->parent = NULL;
226   info->prev = NULL;
227   info->next = NULL;
228}
229
230static void
231unsafe_free(ralloc_header *info)
232{
233   /* Recursively free any children...don't waste time unlinking them. */
234   ralloc_header *temp;
235   while (info->child != NULL) {
236      temp = info->child;
237      info->child = temp->next;
238      unsafe_free(temp);
239   }
240
241   /* Free the block itself.  Call the destructor first, if any. */
242   if (info->destructor != NULL)
243      info->destructor(PTR_FROM_HEADER(info));
244
245   free(info);
246}
247
248void
249ralloc_steal(const void *new_ctx, void *ptr)
250{
251   ralloc_header *info, *parent;
252
253   if (unlikely(ptr == NULL))
254      return;
255
256   info = get_header(ptr);
257   parent = get_header(new_ctx);
258
259   unlink_block(info);
260
261   add_child(parent, info);
262}
263
264void *
265ralloc_parent(const void *ptr)
266{
267   ralloc_header *info;
268
269   if (unlikely(ptr == NULL))
270      return NULL;
271
272   info = get_header(ptr);
273   return info->parent ? PTR_FROM_HEADER(info->parent) : NULL;
274}
275
276static void *autofree_context = NULL;
277
278static void
279autofree(void)
280{
281   ralloc_free(autofree_context);
282}
283
284void *
285ralloc_autofree_context(void)
286{
287   if (unlikely(autofree_context == NULL)) {
288      autofree_context = ralloc_context(NULL);
289      atexit(autofree);
290   }
291   return autofree_context;
292}
293
294void
295ralloc_set_destructor(const void *ptr, void(*destructor)(void *))
296{
297   ralloc_header *info = get_header(ptr);
298   info->destructor = destructor;
299}
300
301char *
302ralloc_strdup(const void *ctx, const char *str)
303{
304   size_t n;
305   char *ptr;
306
307   if (unlikely(str == NULL))
308      return NULL;
309
310   n = strlen(str);
311   ptr = ralloc_array(ctx, char, n + 1);
312   memcpy(ptr, str, n);
313   ptr[n] = '\0';
314   return ptr;
315}
316
317char *
318ralloc_strndup(const void *ctx, const char *str, size_t max)
319{
320   size_t n;
321   char *ptr;
322
323   if (unlikely(str == NULL))
324      return NULL;
325
326   n = strlen(str);
327   if (n > max)
328      n = max;
329
330   ptr = ralloc_array(ctx, char, n + 1);
331   memcpy(ptr, str, n);
332   ptr[n] = '\0';
333   return ptr;
334}
335
336/* helper routine for strcat/strncat - n is the exact amount to copy */
337static bool
338cat(char **dest, const char *str, size_t n)
339{
340   char *both;
341   size_t existing_length;
342   assert(dest != NULL && *dest != NULL);
343
344   existing_length = strlen(*dest);
345   both = resize(*dest, existing_length + n + 1);
346   if (unlikely(both == NULL))
347      return false;
348
349   memcpy(both + existing_length, str, n);
350   both[existing_length + n] = '\0';
351
352   *dest = both;
353   return true;
354}
355
356
357bool
358ralloc_strcat(char **dest, const char *str)
359{
360   return cat(dest, str, strlen(str));
361}
362
363bool
364ralloc_strncat(char **dest, const char *str, size_t n)
365{
366   /* Clamp n to the string length */
367   size_t str_length = strlen(str);
368   if (str_length < n)
369      n = str_length;
370
371   return cat(dest, str, n);
372}
373
374char *
375ralloc_asprintf(const void *ctx, const char *fmt, ...)
376{
377   char *ptr;
378   va_list args;
379   va_start(args, fmt);
380   ptr = ralloc_vasprintf(ctx, fmt, args);
381   va_end(args);
382   return ptr;
383}
384
385/* Return the length of the string that would be generated by a printf-style
386 * format and argument list, not including the \0 byte.
387 */
388static size_t
389printf_length(const char *fmt, va_list untouched_args)
390{
391   int size;
392   char junk;
393
394   /* Make a copy of the va_list so the original caller can still use it */
395   va_list args;
396   va_copy(args, untouched_args);
397
398#ifdef _WIN32
399   /* We need to use _vcsprintf to calculate the size as vsnprintf returns -1
400    * if the number of characters to write is greater than count.
401    */
402   size = _vscprintf(fmt, args);
403   (void)junk;
404#else
405   size = vsnprintf(&junk, 1, fmt, args);
406#endif
407   assert(size >= 0);
408
409   va_end(args);
410
411   return size;
412}
413
414char *
415ralloc_vasprintf(const void *ctx, const char *fmt, va_list args)
416{
417   size_t size = printf_length(fmt, args) + 1;
418
419   char *ptr = ralloc_size(ctx, size);
420   if (ptr != NULL)
421      vsnprintf(ptr, size, fmt, args);
422
423   return ptr;
424}
425
426bool
427ralloc_asprintf_append(char **str, const char *fmt, ...)
428{
429   bool success;
430   va_list args;
431   va_start(args, fmt);
432   success = ralloc_vasprintf_append(str, fmt, args);
433   va_end(args);
434   return success;
435}
436
437bool
438ralloc_vasprintf_append(char **str, const char *fmt, va_list args)
439{
440   size_t existing_length;
441   assert(str != NULL);
442   existing_length = *str ? strlen(*str) : 0;
443   return ralloc_vasprintf_rewrite_tail(str, &existing_length, fmt, args);
444}
445
446bool
447ralloc_asprintf_rewrite_tail(char **str, size_t *start, const char *fmt, ...)
448{
449   bool success;
450   va_list args;
451   va_start(args, fmt);
452   success = ralloc_vasprintf_rewrite_tail(str, start, fmt, args);
453   va_end(args);
454   return success;
455}
456
457bool
458ralloc_vasprintf_rewrite_tail(char **str, size_t *start, const char *fmt,
459			      va_list args)
460{
461   size_t new_length;
462   char *ptr;
463
464   assert(str != NULL);
465
466   if (unlikely(*str == NULL)) {
467      // Assuming a NULL context is probably bad, but it's expected behavior.
468      *str = ralloc_vasprintf(NULL, fmt, args);
469      return true;
470   }
471
472   new_length = printf_length(fmt, args);
473
474   ptr = resize(*str, *start + new_length + 1);
475   if (unlikely(ptr == NULL))
476      return false;
477
478   vsnprintf(ptr + *start, new_length + 1, fmt, args);
479   *str = ptr;
480   *start += new_length;
481   return true;
482}
483