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 #include <stdlib.h>
  10
  11 #define BT_LOG_OUTPUT_LEVEL ctf_plugin_metadata_log_level
  12 #define BT_LOG_TAG          "PLUGIN/CTF/META/OBJSTACK"
  13 #include "logging.hpp"
  14
  15 #include "common/align.h"
  16 #include "common/list.h"
  17 #include "common/macros.h"
  18
  19 #include "objstack.hpp"
  20
  21 #define OBJSTACK_ALIGN    8 /* Object stack alignment */
  22 #define OBJSTACK_INIT_LEN 128
  23 #define OBJSTACK_POISON   0xcc
  24
  25 struct objstack
  26 {
  27     struct bt_list_head head; /* list of struct objstack_node */
  28 };
  29
  30 struct objstack_node
  31 {
  32     struct bt_list_head node;
  33     size_t len;
  34     size_t used_len;
  35     char __attribute__((aligned(OBJSTACK_ALIGN))) data[];
  36 };
  37
  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 void objstack_destroy(struct objstack *objstack)
  75 {
  76     struct objstack_node *node, *p;
  77
  78     if (!objstack)
  79         return;
  80     bt_list_for_each_entry_safe (node, p, &objstack->head, node) {
  81         bt_list_del(&node->node);
  82         objstack_node_free(node);
  83     }
  84     free(objstack);
  85 }
  86
  87 static struct objstack_node *objstack_append_node(struct objstack *objstack)
  88 {
  89     struct objstack_node *last_node, *new_node;
  90
  91     /* Get last node */
  92     last_node = bt_list_entry(objstack->head.prev, struct objstack_node, node);
  93
  94     /* Allocate new node with double of size of last node */
  95     new_node = (objstack_node *) calloc(sizeof(struct objstack_node) + (last_node->len << 1),
  96                                         sizeof(char));
  97     if (!new_node) {
  98         BT_LOGE_STR("Failed to allocate one object stack node.");
  99         return NULL;
 100     }
 101     bt_list_add_tail(&new_node->node, &objstack->head);
 102     new_node->len = last_node->len << 1;
 103     return new_node;
 104 }
 105
 106 void *objstack_alloc(struct objstack *objstack, size_t len)
 107 {
 108     struct objstack_node *last_node;
 109     void *p;
 110
 111     len = BT_ALIGN(len, OBJSTACK_ALIGN);
 112
 113     /* Get last node */
 114     last_node = bt_list_entry(objstack->head.prev, struct objstack_node, node);
 115     while (last_node->len - last_node->used_len < len) {
 116         last_node = objstack_append_node(objstack);
 117         if (!last_node) {
 118             return NULL;
 119         }
 120     }
 121     p = &last_node->data[last_node->used_len];
 122     last_node->used_len += len;
 123     return p;
 124 }