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

   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.h"
  12
  13 #include "objstack.h"
  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         struct bt_list_head head;       /* list of struct objstack_node */
  26 };
  27
  28 struct objstack_node {
  29         struct bt_list_head node;
  30         size_t len;
  31         size_t used_len;
  32         char __attribute__ ((aligned (OBJSTACK_ALIGN))) data[];
  33 };
  34
  35 BT_HIDDEN
  36 struct objstack *objstack_create(void)
  37 {
  38         struct objstack *objstack;
  39         struct objstack_node *node;
  40
  41         objstack = calloc(1, sizeof(*objstack));
  42         if (!objstack) {
  43                 BT_LOGE_STR("Failed to allocate one object stack.");
  44                 return NULL;
  45         }
  46         node = calloc(sizeof(struct objstack_node) + OBJSTACK_INIT_LEN,
  47                         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
  60 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
  89 struct objstack_node *objstack_append_node(struct objstack *objstack)
  90 {
  91         struct objstack_node *last_node, *new_node;
  92
  93         /* Get last node */
  94         last_node = bt_list_entry(objstack->head.prev,
  95                         struct objstack_node, node);
  96
  97         /* Allocate new node with double of size of last node */
  98         new_node = calloc(sizeof(struct objstack_node) + (last_node->len << 1),
  99                         sizeof(char));
 100         if (!new_node) {
 101                 BT_LOGE_STR("Failed to allocate one object stack node.");
 102                 return NULL;
 103         }
 104         bt_list_add_tail(&new_node->node, &objstack->head);
 105         new_node->len = last_node->len << 1;
 106         return new_node;
 107 }
 108
 109 BT_HIDDEN
 110 void *objstack_alloc(struct objstack *objstack, size_t len)
 111 {
 112         struct objstack_node *last_node;
 113         void *p;
 114
 115         len = ALIGN(len, OBJSTACK_ALIGN);
 116
 117         /* Get last node */
 118         last_node = bt_list_entry(objstack->head.prev,
 119                         struct objstack_node, node);
 120         while (last_node->len - last_node->used_len < len) {
 121                 last_node = objstack_append_node(objstack);
 122                 if (!last_node) {
 123                         return NULL;
 124                 }
 125         }
 126         p = &last_node->data[last_node->used_len];
 127         last_node->used_len += len;
 128         return p;
 129 }