Add built-in debug malloc wrapper.

[srvx.git] / src / alloc-srvx.c

diff --git a/src/alloc-srvx.c b/src/alloc-srvx.c
new file mode 100644 (file)
index 0000000..91d9035
--- /dev/null
+++ b/src/alloc-srvx.c
@@ -0,0 +1,128 @@
+/* alloc-srvx.c - Debug allocation wrapper
+ * Copyright 2005 srvx Development Team
+ *
+ * This file is part of srvx.
+ *
+ * srvx is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "common.h"
+
+#undef malloc
+#undef free
+
+/* cookies for anybody who recognizes these bytes without help :) */
+#define ALLOC_MAGIC 0x1acf
+#define FREE_MAGIC  0xfc1d
+
+struct alloc_header {
+    unsigned int file_id : 8;
+    unsigned int size : 24;
+    unsigned int line : 16;
+    unsigned int magic : 16;
+};
+
+static char file_id_map[256][32];
+static unsigned int file_ids_used;
+
+static int
+file_id_cmp(const void *a_, const void *b_)
+{
+    return strcmp(a_, b_);
+}
+
+static unsigned int
+get_file_id(const char *fname)
+{
+    void *entry;
+
+    entry = bsearch(fname, file_id_map, file_ids_used, sizeof(file_id_map[0]), file_id_cmp);
+    if (entry)
+        return ((char*)entry - file_id_map[0]) / sizeof(file_id_map[0]);
+    strcpy(file_id_map[file_ids_used++], fname);
+    qsort(file_id_map, file_ids_used, sizeof(file_id_map[0]), file_id_cmp);
+    return file_ids_used - 1;
+}
+
+void *
+srvx_malloc(const char *file, unsigned int line, size_t size)
+{
+    struct alloc_header *block;
+
+    block = malloc(sizeof(*block) + size);
+    assert(block != NULL);
+    memset(block, 0, sizeof(*block) + size);
+    block->file_id = get_file_id(file);
+    block->line = line;
+    block->size = size;
+    block->magic = ALLOC_MAGIC;
+    return block + 1;
+}
+
+void *
+srvx_realloc(const char *file, unsigned int line, void *ptr, size_t size)
+{
+    struct alloc_header *block = NULL, *newblock;
+
+    if (ptr) {
+        block = (struct alloc_header *)ptr - 1;
+        assert(block->magic == ALLOC_MAGIC);
+        if (block->size >= size)
+            return block + 1;
+    }
+
+    newblock = malloc(sizeof(*newblock) + size);
+    assert(newblock != NULL);
+    memset(newblock, 0, sizeof(*newblock) + size);
+    newblock->file_id = get_file_id(file);
+    newblock->line = line;
+    newblock->size = size;
+    newblock->magic = ALLOC_MAGIC;
+
+    if (ptr) {
+        memcpy(newblock + 1, block + 1, block->size);
+        size = block->size + sizeof(*block);
+        memset(block, 0, size);
+        block->magic = FREE_MAGIC;
+        free(block);
+    }
+
+    return newblock + 1;
+}
+
+char *
+srvx_strdup(const char *file, unsigned int line, const char *src)
+{
+    char *target;
+    size_t len;
+
+    len = strlen(src) + 1;
+    target = srvx_malloc(file, line, len);
+    memcpy(target, src, len);
+    return target;
+}
+
+void
+srvx_free(const char *file, unsigned int line, void *ptr)
+{
+    struct alloc_header *block;
+    size_t size;
+
+    if (!ptr)
+        return;
+    block = (struct alloc_header *)ptr - 1;
+    assert(block->magic == ALLOC_MAGIC);
+    size = block->size + sizeof(*block);
+    memset(block, 0, size);
+    block->magic = FREE_MAGIC;
+    free(block);
+    (void)file; (void)line;
+}