src/alloc-x3.c

   1 /* alloc-srvx.c - Debug allocation wrapper
   2  * Copyright 2005 srvx Development Team
   3  *
   4  * This file is part of srvx.
   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 3 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
  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
  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/%lu; allocated by %u:%u/%u).",
  67                    block, file, line, (unsigned long)size,
  68                    block->file_id, block->line, block->size);
  69     }
  70     memset(block, 0, sizeof(*block) + size);
  71     memcpy((char*)(block + 1) + size, redzone, sizeof(redzone));
  72     block->file_id = get_file_id(file);
  73     block->line = line;
  74     block->size = size;
  75     block->magic = ALLOC_MAGIC;
  76     alloc_count++;
  77     alloc_size += size;
  78     return block + 1;
  79 }
  80
  81 void *
  82 x3_realloc(const char *file, unsigned int line, void *ptr, size_t size)
  83 {
  84     struct alloc_header *block, *newblock;
  85
  86     if (!ptr)
  87         return x3_malloc(file, line, size);
  88
  89     verify(ptr);
  90     block = (struct alloc_header *)ptr - 1;
  91
  92     if (block->size >= size)
  93         return block + 1;
  94
  95     newblock = malloc(sizeof(*newblock) + size + sizeof(redzone));
  96     assert(newblock != NULL);
  97     memset(newblock, 0, sizeof(*newblock));
  98     memcpy(newblock + 1, block + 1, block->size);
  99     memset((char*)(newblock + 1) + block->size, 0, size - block->size);
 100     memcpy((char*)(newblock + 1) + size, redzone, sizeof(redzone));
 101     newblock->file_id = get_file_id(file);
 102     newblock->line = line;
 103     newblock->size = size;
 104     newblock->magic = ALLOC_MAGIC;
 105     alloc_count++;
 106     alloc_size += size;
 107
 108     x3_free(file, line, block + 1);
 109
 110     return newblock + 1;
 111 }
 112
 113 char *
 114 x3_strdup(const char *file, unsigned int line, const char *src)
 115 {
 116     char *target;
 117     size_t len;
 118
 119     len = strlen(src) + 1;
 120     target = x3_malloc(file, line, len);
 121     memcpy(target, src, len);
 122     return target;
 123 }
 124
 125 void
 126 x3_free(UNUSED_ARG(const char *file), UNUSED_ARG(unsigned int line), void *ptr)
 127 {
 128     struct alloc_header *block;
 129     size_t size;
 130
 131     if (!ptr)
 132         return;
 133     verify(ptr);
 134     block = (struct alloc_header *)ptr - 1;
 135     size = block->size;
 136     memset(block + 1, 0xde, size);
 137     block->magic = FREE_MAGIC;
 138     free(block);
 139     alloc_count--;
 140     alloc_size -= size;
 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 }