src/plugins/ctf/common/metadata/objstack.c

   1 /*
   2  * objstack.c
   3  *
   4  * Common Trace Format Object Stack.
   5  *
   6  * Copyright 2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24  * SOFTWARE.
  25  */
  26
  27 #define BT_LOG_TAG "PLUGIN-CTF-METADATA-OBJSTACK"
  28 #include "logging.h"
  29
  30 #include <stdlib.h>
  31 #include "common/list.h"
  32 #include "common/macros.h"
  33 #include "common/align.h"
  34
  35 #define OBJSTACK_ALIGN                  8       /* Object stack alignment */
  36 #define OBJSTACK_INIT_LEN               128
  37 #define OBJSTACK_POISON                 0xcc
  38
  39 struct objstack {
  40         struct bt_list_head head;       /* list of struct objstack_node */
  41 };
  42
  43 struct objstack_node {
  44         struct bt_list_head node;
  45         size_t len;
  46         size_t used_len;
  47         char __attribute__ ((aligned (OBJSTACK_ALIGN))) data[];
  48 };
  49
  50 BT_HIDDEN
  51 struct objstack *objstack_create(void)
  52 {
  53         struct objstack *objstack;
  54         struct objstack_node *node;
  55
  56         objstack = calloc(1, sizeof(*objstack));
  57         if (!objstack) {
  58                 BT_LOGE_STR("Failed to allocate one object stack.");
  59                 return NULL;
  60         }
  61         node = calloc(sizeof(struct objstack_node) + OBJSTACK_INIT_LEN,
  62                         sizeof(char));
  63         if (!node) {
  64                 BT_LOGE_STR("Failed to allocate one object stack node.");
  65                 free(objstack);
  66                 return NULL;
  67         }
  68         BT_INIT_LIST_HEAD(&objstack->head);
  69         bt_list_add_tail(&node->node, &objstack->head);
  70         node->len = OBJSTACK_INIT_LEN;
  71         return objstack;
  72 }
  73
  74 static
  75 void objstack_node_free(struct objstack_node *node)
  76 {
  77         size_t offset, len;
  78         char *p;
  79
  80         if (!node)
  81                 return;
  82         p = (char *) node;
  83         len = sizeof(*node) + node->len;
  84         for (offset = 0; offset < len; offset++)
  85                 p[offset] = OBJSTACK_POISON;
  86         free(node);
  87 }
  88
  89 BT_HIDDEN
  90 void objstack_destroy(struct objstack *objstack)
  91 {
  92         struct objstack_node *node, *p;
  93
  94         if (!objstack)
  95                 return;
  96         bt_list_for_each_entry_safe(node, p, &objstack->head, node) {
  97                 bt_list_del(&node->node);
  98                 objstack_node_free(node);
  99         }
 100         free(objstack);
 101 }
 102
 103 static
 104 struct objstack_node *objstack_append_node(struct objstack *objstack)
 105 {
 106         struct objstack_node *last_node, *new_node;
 107
 108         /* Get last node */
 109         last_node = bt_list_entry(objstack->head.prev,
 110                         struct objstack_node, node);
 111
 112         /* Allocate new node with double of size of last node */
 113         new_node = calloc(sizeof(struct objstack_node) + (last_node->len << 1),
 114                         sizeof(char));
 115         if (!new_node) {
 116                 BT_LOGE_STR("Failed to allocate one object stack node.");
 117                 return NULL;
 118         }
 119         bt_list_add_tail(&new_node->node, &objstack->head);
 120         new_node->len = last_node->len << 1;
 121         return new_node;
 122 }
 123
 124 BT_HIDDEN
 125 void *objstack_alloc(struct objstack *objstack, size_t len)
 126 {
 127         struct objstack_node *last_node;
 128         void *p;
 129
 130         len = ALIGN(len, OBJSTACK_ALIGN);
 131
 132         /* Get last node */
 133         last_node = bt_list_entry(objstack->head.prev,
 134                         struct objstack_node, node);
 135         while (last_node->len - last_node->used_len < len) {
 136                 last_node = objstack_append_node(objstack);
 137                 if (!last_node) {
 138                         return NULL;
 139                 }
 140         }
 141         p = &last_node->data[last_node->used_len];
 142         last_node->used_len += len;
 143         return p;
 144 }