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 struct objstack *objstack_create(void)
  38 {
  39     struct objstack *objstack;
  40     struct objstack_node *node;
  41
  42     objstack = (struct objstack *) calloc(1, sizeof(*objstack));
  43     if (!objstack) {
  44         BT_LOGE_STR("Failed to allocate one object stack.");
  45         return NULL;
  46     }
  47     node = (objstack_node *) calloc(sizeof(struct objstack_node) + OBJSTACK_INIT_LEN, sizeof(char));
  48     if (!node) {
  49         BT_LOGE_STR("Failed to allocate one object stack node.");
  50         free(objstack);
  51         return NULL;
  52     }
  53     BT_INIT_LIST_HEAD(&objstack->head);
  54     bt_list_add_tail(&node->node, &objstack->head);
  55     node->len = OBJSTACK_INIT_LEN;
  56     return objstack;
  57 }
  58
  59 static void objstack_node_free(struct objstack_node *node)
  60 {
  61     size_t offset, len;
  62     char *p;
  63
  64     if (!node)
  65         return;
  66     p = (char *) node;
  67     len = sizeof(*node) + node->len;
  68     for (offset = 0; offset < len; offset++)
  69         p[offset] = OBJSTACK_POISON;
  70     free(node);
  71 }
  72
  73 void objstack_destroy(struct objstack *objstack)
  74 {
  75     struct objstack_node *node, *p;
  76
  77     if (!objstack)
  78         return;
  79     bt_list_for_each_entry_safe (node, p, &objstack->head, node) {
  80         bt_list_del(&node->node);
  81         objstack_node_free(node);
  82     }
  83     free(objstack);
  84 }
  85
  86 static struct objstack_node *objstack_append_node(struct objstack *objstack)
  87 {
  88     struct objstack_node *last_node, *new_node;
  89
  90     /* Get last node */
  91     last_node = bt_list_entry(objstack->head.prev, struct objstack_node, node);
  92
  93     /* Allocate new node with double of size of last node */
  94     new_node = (objstack_node *) calloc(sizeof(struct objstack_node) + (last_node->len << 1),
  95                                         sizeof(char));
  96     if (!new_node) {
  97         BT_LOGE_STR("Failed to allocate one object stack node.");
  98         return NULL;
  99     }
 100     bt_list_add_tail(&new_node->node, &objstack->head);
 101     new_node->len = last_node->len << 1;
 102     return new_node;
 103 }
 104
 105 void *objstack_alloc(struct objstack *objstack, size_t len)
 106 {
 107     struct objstack_node *last_node;
 108     void *p;
 109
 110     len = BT_ALIGN(len, OBJSTACK_ALIGN);
 111
 112     /* Get last node */
 113     last_node = bt_list_entry(objstack->head.prev, struct objstack_node, node);
 114     while (last_node->len - last_node->used_len < len) {
 115         last_node = objstack_append_node(objstack);
 116         if (!last_node) {
 117             return NULL;
 118         }
 119     }
 120     p = &last_node->data[last_node->used_len];
 121     last_node->used_len += len;
 122     return p;
 123 }