src/alloc-x3.c

   1 /* alloc-x3.c - Debug allocation wrapper
   2  * Copyright 2005 srvx Development Team
   3  *
   4  * This file is part of x3.
   5  *
   6  * srvx is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include "common.h"
  18 #include "log.h"
  19
  20 #undef malloc
  21 #undef free
  22 /* cookies for anybody who recognizes these bytes without help :) */
  23 #define ALLOC_MAGIC 0x1acf
  24 #define FREE_MAGIC  0xfc1d
  25 const char redzone[] = { '\x03', '\x47', '\x76', '\xc7' };
  26
  27 struct alloc_header {
  28     unsigned int file_id : 8;
  29     unsigned int size : 24;
  30     unsigned int line : 16;
  31     unsigned int magic : 16;
  32 };
  33
  34 static char file_id_map[256][32];
  35 static unsigned int file_ids_used;
  36 unsigned long alloc_count, alloc_size;
  37
  38 static int
  39 file_id_cmp(const void *a_, const void *b_)
  40 {
  41     return strcmp(a_, b_);
  42 }
  43
  44 static unsigned int
  45 get_file_id(const char *fname)
  46 {
  47     void *entry;
  48
  49     entry = bsearch(fname, file_id_map, file_ids_used, sizeof(file_id_map[0]), file_id_cmp);
  50     if (entry)
  51         return ((char*)entry - file_id_map[0]) / sizeof(file_id_map[0]);
  52     strcpy(file_id_map[file_ids_used++], fname);
  53     qsort(file_id_map, file_ids_used, sizeof(file_id_map[0]), file_id_cmp);
  54     return file_ids_used - 1;
  55 }
  56
  57 void *
  58 x3_malloc(const char *file, unsigned int line, size_t size)
  59 {
  60     struct alloc_header *block;
  61     block = malloc(sizeof(*block) + size);
  62     block = malloc(sizeof(*block) + size + sizeof(redzone));
  63     assert(block != NULL);
  64     if (block->magic == ALLOC_MAGIC && block->file_id < file_ids_used) {
  65         /* Only report the error, due to possible false positives. */
  66         log_module(MAIN_LOG, LOG_WARNING, "Detected possible reallocation: %p (called by %s:%u/%u; allocated by %u:%u/%u).",
  67                    block, file, line, size, block->file_id, block->line, block->size);
  68     }
  69     memset(block, 0, sizeof(*block) + size);
  70     memcpy((char*)(block + 1) + size, redzone, sizeof(redzone));
  71     block->file_id = get_file_id(file);
  72     block->line = line;
  73     block->size = size;
  74     block->magic = ALLOC_MAGIC;
  75     alloc_count++;
  76     alloc_size += size;
  77     return block + 1;
  78 }
  79
  80 void *
  81 x3_realloc(const char *file, unsigned int line, void *ptr, size_t size)
  82     struct alloc_header *block = NULL, *newblock;
  83     struct alloc_header *block, *newblock;
  84     }
  85     if (!ptr)
  86         return x3_malloc(file, line, size);
  87
  88     verify(ptr);
  89     block = (struct alloc_header *)ptr - 1;
  90
  91     if (block->size >= size)
  92         return block + 1;
  93     newblock = malloc(sizeof(*newblock) + size);
  94     newblock = malloc(sizeof(*newblock) + size + sizeof(redzone));
  95     memset(newblock, 0, sizeof(*newblock) + size + sizeof(redzone));
  96     memset(newblock, 0, sizeof(*newblock));
  97     memcpy(newblock + 1, block + 1, block->size);
  98     memset((char*)(newblock + 1) + block->size, 0, size - block->size);
  99     memcpy((char*)(newblock + 1) + size, redzone, sizeof(redzone));
 100     newblock->file_id = get_file_id(file);
 101     newblock->line = line;
 102     newblock->size = size;
 103     newblock->magic = ALLOC_MAGIC;
 104     alloc_count++;
 105     alloc_size += size;
 106     x3_free(block);
 107     x3_free(file, line, block + 1);
 108
 109     return newblock + 1;
 110 }
 111
 112 char *
 113 x3_strdup(const char *file, unsigned int line, const char *src)
 114 {
 115     char *target;
 116     size_t len;
 117
 118     len = strlen(src) + 1;
 119     target = x3_malloc(file, line, len);
 120     memcpy(target, src, len);
 121     return target;
 122 }
 123
 124 x3_free(const char *file, unsigned int line, void *ptr)
 125 x3_free(UNUSED_ARG(const char *file), UNUSED_ARG(unsigned int line), void *ptr)
 126 {
 127     struct alloc_header *block;
 128     size_t size;
 129
 130     if (!ptr)
 131         return;
 132     verify(ptr);
 133     assert(block->magic == ALLOC_MAGIC);
 134     memset(block, 0, size);
 135     size = block->size;
 136     memset(block + 1, 0xde, size);
 137     block->magic = FREE_MAGIC;
 138     free(block);
 139     alloc_size -= size - sizeof(*block);
 140     (void)file; (void)line;
 141 }
 142
 143 void
 144 verify(const void *ptr)
 145 {
 146     const struct alloc_header *header;
 147     if (!ptr)
 148         return;
 149     header = (const struct alloc_header*)ptr - 1;
 150     assert(header->magic == ALLOC_MAGIC);
 151     assert(!memcmp((char*)(header + 1) + header->size, redzone, sizeof(redzone)));
 152 }
 153