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 "objstack.h"
  32
  33 #include <stdlib.h>
  34 #include "common/list.h"
  35 #include "common/macros.h"
  36 #include "common/align.h"
  37
  38 #define OBJSTACK_ALIGN                  8       /* Object stack alignment */
  39 #define OBJSTACK_INIT_LEN               128
  40 #define OBJSTACK_POISON                 0xcc
  41
  42 struct objstack {
  43         struct bt_list_head head;       /* list of struct objstack_node */
  44 };
  45
  46 struct objstack_node {
  47         struct bt_list_head node;
  48         size_t len;
  49         size_t used_len;
  50         char __attribute__ ((aligned (OBJSTACK_ALIGN))) data[];
  51 };
  52
  53 BT_HIDDEN
  54 struct objstack *objstack_create(void)
  55 {
  56         struct objstack *objstack;
  57         struct objstack_node *node;
  58
  59         objstack = calloc(1, sizeof(*objstack));
  60         if (!objstack) {
  61                 BT_LOGE_STR("Failed to allocate one object stack.");
  62                 return NULL;
  63         }
  64         node = calloc(sizeof(struct objstack_node) + OBJSTACK_INIT_LEN,
  65                         sizeof(char));
  66         if (!node) {
  67                 BT_LOGE_STR("Failed to allocate one object stack node.");
  68                 free(objstack);
  69                 return NULL;
  70         }
  71         BT_INIT_LIST_HEAD(&objstack->head);
  72         bt_list_add_tail(&node->node, &objstack->head);
  73         node->len = OBJSTACK_INIT_LEN;
  74         return objstack;
  75 }
  76
  77 static
  78 void objstack_node_free(struct objstack_node *node)
  79 {
  80         size_t offset, len;
  81         char *p;
  82
  83         if (!node)
  84                 return;
  85         p = (char *) node;
  86         len = sizeof(*node) + node->len;
  87         for (offset = 0; offset < len; offset++)
  88                 p[offset] = OBJSTACK_POISON;
  89         free(node);
  90 }
  91
  92 BT_HIDDEN
  93 void objstack_destroy(struct objstack *objstack)
  94 {
  95         struct objstack_node *node, *p;
  96
  97         if (!objstack)
  98                 return;
  99         bt_list_for_each_entry_safe(node, p, &objstack->head, node) {
 100                 bt_list_del(&node->node);
 101                 objstack_node_free(node);
 102         }
 103         free(objstack);
 104 }
 105
 106 static
 107 struct objstack_node *objstack_append_node(struct objstack *objstack)
 108 {
 109         struct objstack_node *last_node, *new_node;
 110
 111         /* Get last node */
 112         last_node = bt_list_entry(objstack->head.prev,
 113                         struct objstack_node, node);
 114
 115         /* Allocate new node with double of size of last node */
 116         new_node = calloc(sizeof(struct objstack_node) + (last_node->len << 1),
 117                         sizeof(char));
 118         if (!new_node) {
 119                 BT_LOGE_STR("Failed to allocate one object stack node.");
 120                 return NULL;
 121         }
 122         bt_list_add_tail(&new_node->node, &objstack->head);
 123         new_node->len = last_node->len << 1;
 124         return new_node;
 125 }
 126
 127 BT_HIDDEN
 128 void *objstack_alloc(struct objstack *objstack, size_t len)
 129 {
 130         struct objstack_node *last_node;
 131         void *p;
 132
 133         len = ALIGN(len, OBJSTACK_ALIGN);
 134
 135         /* Get last node */
 136         last_node = bt_list_entry(objstack->head.prev,
 137                         struct objstack_node, node);
 138         while (last_node->len - last_node->used_len < len) {
 139                 last_node = objstack_append_node(objstack);
 140                 if (!last_node) {
 141                         return NULL;
 142                 }
 143         }
 144         p = &last_node->data[last_node->used_len];
 145         last_node->used_len += len;
 146         return p;
 147 }