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

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright 2013 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * Common Trace Format Object Stack.
   7  */
   8
   9 #define BT_LOG_OUTPUT_LEVEL ctf_plugin_metadata_log_level
  10 #define BT_LOG_TAG          "PLUGIN/CTF/META/OBJSTACK"
  11 #include "logging.hpp"
  12
  13 #include "objstack.hpp"
  14
  15 #include <stdlib.h>
  16 #include "common/list.h"
  17 #include "common/macros.h"
  18 #include "common/align.h"
  19
  20 #define OBJSTACK_ALIGN    8 /* Object stack alignment */
  21 #define OBJSTACK_INIT_LEN 128
  22 #define OBJSTACK_POISON   0xcc
  23
  24 struct objstack
  25 {
  26     struct bt_list_head head; /* list of struct objstack_node */
  27 };
  28
  29 struct objstack_node
  30 {
  31     struct bt_list_head node;
  32     size_t len;
  33     size_t used_len;
  34     char __attribute__((aligned(OBJSTACK_ALIGN))) data[];
  35 };
  36
  37 BT_HIDDEN
  38 struct objstack *objstack_create(void)
  39 {
  40     struct objstack *objstack;
  41     struct objstack_node *node;
  42
  43     objstack = (struct objstack *) calloc(1, sizeof(*objstack));
  44     if (!objstack) {
  45         BT_LOGE_STR("Failed to allocate one object stack.");
  46         return NULL;
  47     }
  48     node = (objstack_node *) calloc(sizeof(struct objstack_node) + OBJSTACK_INIT_LEN, sizeof(char));
  49     if (!node) {
  50         BT_LOGE_STR("Failed to allocate one object stack node.");
  51         free(objstack);
  52         return NULL;
  53     }
  54     BT_INIT_LIST_HEAD(&objstack->head);
  55     bt_list_add_tail(&node->node, &objstack->head);
  56     node->len = OBJSTACK_INIT_LEN;
  57     return objstack;
  58 }
  59
  60 static void objstack_node_free(struct objstack_node *node)
  61 {
  62     size_t offset, len;
  63     char *p;
  64
  65     if (!node)
  66         return;
  67     p = (char *) node;
  68     len = sizeof(*node) + node->len;
  69     for (offset = 0; offset < len; offset++)
  70         p[offset] = OBJSTACK_POISON;
  71     free(node);
  72 }
  73
  74 BT_HIDDEN
  75 void objstack_destroy(struct objstack *objstack)
  76 {
  77     struct objstack_node *node, *p;
  78
  79     if (!objstack)
  80         return;
  81     bt_list_for_each_entry_safe (node, p, &objstack->head, node) {
  82         bt_list_del(&node->node);
  83         objstack_node_free(node);
  84     }
  85     free(objstack);
  86 }
  87
  88 static struct objstack_node *objstack_append_node(struct objstack *objstack)
  89 {
  90     struct objstack_node *last_node, *new_node;
  91
  92     /* Get last node */
  93     last_node = bt_list_entry(objstack->head.prev, struct objstack_node, node);
  94
  95     /* Allocate new node with double of size of last node */
  96     new_node = (objstack_node *) calloc(sizeof(struct objstack_node) + (last_node->len << 1),
  97                                         sizeof(char));
  98     if (!new_node) {
  99         BT_LOGE_STR("Failed to allocate one object stack node.");
 100         return NULL;
 101     }
 102     bt_list_add_tail(&new_node->node, &objstack->head);
 103     new_node->len = last_node->len << 1;
 104     return new_node;
 105 }
 106
 107 BT_HIDDEN
 108 void *objstack_alloc(struct objstack *objstack, size_t len)
 109 {
 110     struct objstack_node *last_node;
 111     void *p;
 112
 113     len = BT_ALIGN(len, OBJSTACK_ALIGN);
 114
 115     /* Get last node */
 116     last_node = bt_list_entry(objstack->head.prev, struct objstack_node, node);
 117     while (last_node->len - last_node->used_len < len) {
 118         last_node = objstack_append_node(objstack);
 119         if (!last_node) {
 120             return NULL;
 121         }
 122     }
 123     p = &last_node->data[last_node->used_len];
 124     last_node->used_len += len;
 125     return p;
 126 }