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_OUTPUT_LEVEL ctf_plugin_metadata_log_level
  28 #define BT_LOG_TAG "PLUGIN/CTF/META/OBJSTACK"
  29 #include "logging.h"
  30
  31 #include <stdlib.h>
  32 #include "common/list.h"
  33 #include "common/macros.h"
  34 #include "common/align.h"
  35
  36 #define OBJSTACK_ALIGN                  8       /* Object stack alignment */
  37 #define OBJSTACK_INIT_LEN               128
  38 #define OBJSTACK_POISON                 0xcc
  39
  40 struct objstack {
  41         struct bt_list_head head;       /* list of struct objstack_node */
  42 };
  43
  44 struct objstack_node {
  45         struct bt_list_head node;
  46         size_t len;
  47         size_t used_len;
  48         char __attribute__ ((aligned (OBJSTACK_ALIGN))) data[];
  49 };
  50
  51 BT_HIDDEN
  52 struct objstack *objstack_create(void)
  53 {
  54         struct objstack *objstack;
  55         struct objstack_node *node;
  56
  57         objstack = calloc(1, sizeof(*objstack));
  58         if (!objstack) {
  59                 BT_LOGE_STR("Failed to allocate one object stack.");
  60                 return NULL;
  61         }
  62         node = calloc(sizeof(struct objstack_node) + OBJSTACK_INIT_LEN,
  63                         sizeof(char));
  64         if (!node) {
  65                 BT_LOGE_STR("Failed to allocate one object stack node.");
  66                 free(objstack);
  67                 return NULL;
  68         }
  69         BT_INIT_LIST_HEAD(&objstack->head);
  70         bt_list_add_tail(&node->node, &objstack->head);
  71         node->len = OBJSTACK_INIT_LEN;
  72         return objstack;
  73 }
  74
  75 static
  76 void objstack_node_free(struct objstack_node *node)
  77 {
  78         size_t offset, len;
  79         char *p;
  80
  81         if (!node)
  82                 return;
  83         p = (char *) node;
  84         len = sizeof(*node) + node->len;
  85         for (offset = 0; offset < len; offset++)
  86                 p[offset] = OBJSTACK_POISON;
  87         free(node);
  88 }
  89
  90 BT_HIDDEN
  91 void objstack_destroy(struct objstack *objstack)
  92 {
  93         struct objstack_node *node, *p;
  94
  95         if (!objstack)
  96                 return;
  97         bt_list_for_each_entry_safe(node, p, &objstack->head, node) {
  98                 bt_list_del(&node->node);
  99                 objstack_node_free(node);
 100         }
 101         free(objstack);
 102 }
 103
 104 static
 105 struct objstack_node *objstack_append_node(struct objstack *objstack)
 106 {
 107         struct objstack_node *last_node, *new_node;
 108
 109         /* Get last node */
 110         last_node = bt_list_entry(objstack->head.prev,
 111                         struct objstack_node, node);
 112
 113         /* Allocate new node with double of size of last node */
 114         new_node = calloc(sizeof(struct objstack_node) + (last_node->len << 1),
 115                         sizeof(char));
 116         if (!new_node) {
 117                 BT_LOGE_STR("Failed to allocate one object stack node.");
 118                 return NULL;
 119         }
 120         bt_list_add_tail(&new_node->node, &objstack->head);
 121         new_node->len = last_node->len << 1;
 122         return new_node;
 123 }
 124
 125 BT_HIDDEN
 126 void *objstack_alloc(struct objstack *objstack, size_t len)
 127 {
 128         struct objstack_node *last_node;
 129         void *p;
 130
 131         len = ALIGN(len, OBJSTACK_ALIGN);
 132
 133         /* Get last node */
 134         last_node = bt_list_entry(objstack->head.prev,
 135                         struct objstack_node, node);
 136         while (last_node->len - last_node->used_len < len) {
 137                 last_node = objstack_append_node(objstack);
 138                 if (!last_node) {
 139                         return NULL;
 140                 }
 141         }
 142         p = &last_node->data[last_node->used_len];
 143         last_node->used_len += len;
 144         return p;
 145 }