--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dbmalloc.c	Sun May 21 10:54:11 2017 +0800
@@ -0,0 +1,128 @@
+#include "dbmalloc.h"
+#include "dbutil.h"
+
+#define LIST_SIZE 1000
+
+struct dbmalloc_header {
+    unsigned int index;
+    unsigned int epoch;
+};
+
+static struct dbmalloc_header* dbmalloc_list[LIST_SIZE];
+
+unsigned int current_epoch = 0;
+
+void m_malloc_set_epoch(unsigned int epoch) {
+    current_epoch = epoch;
+}
+
+void m_malloc_free_epoch(unsigned int epoch) {
+    unsigned int i;
+    unsigned int freed = 0;
+    for (i = 0; i < LIST_SIZE; i++) {
+        if (dbmalloc_list[i] != NULL) {
+            assert(dbmalloc_list[i]->index == i);
+            if (dbmalloc_list[i]->epoch == epoch) {
+                free(dbmalloc_list[i]);
+                dbmalloc_list[i] = NULL;
+                freed++;
+            }
+        }
+    }
+    TRACE(("free_epoch freed %d", freed))
+}
+
+static void put_alloc(struct dbmalloc_header *header) {
+    unsigned int i;
+    for (i = 0; i < LIST_SIZE; i++) {
+        if (dbmalloc_list[i] == NULL) {
+            dbmalloc_list[i] = header;
+            header->index = i;
+            return;
+        }
+    }
+    dropbear_exit("ran out of dbmalloc entries");
+}
+
+static void remove_alloc(struct dbmalloc_header *header) {
+    assert(header->index < LIST_SIZE);
+    assert(dbmalloc_list[header->index] == header);
+    assert(header->epoch == current_epoch);
+    dbmalloc_list[header->index] = NULL;
+}
+
+static struct dbmalloc_header* get_header(void* ptr) {
+    char* bptr = ptr;
+    return (struct dbmalloc_header*)&bptr[-sizeof(struct dbmalloc_header)];
+}
+
+void * m_malloc(size_t size) {
+    char* mem = NULL;
+    struct dbmalloc_header* header = NULL;
+
+    if (size == 0 || size > 1e9) {
+        dropbear_exit("m_malloc failed");
+    }
+
+    size = size + sizeof(struct dbmalloc_header);
+
+    mem = calloc(1, size);
+    if (mem == NULL) {
+        dropbear_exit("m_malloc failed");
+    }
+    header = (struct dbmalloc_header*)mem;
+    put_alloc(header);
+    header->epoch = current_epoch;
+    return &mem[sizeof(struct dbmalloc_header)];
+}
+
+void * m_calloc(size_t nmemb, size_t size) {
+    assert(nmemb <= 1000 && size <= 10000);
+    return m_malloc(nmemb*size);
+}
+
+void * m_realloc(void* ptr, size_t size) {
+    char* mem = NULL;
+    struct dbmalloc_header* header = NULL;
+    if (size == 0 || size > 1e9) {
+        dropbear_exit("m_realloc failed");
+    }
+
+    header = get_header(ptr);
+    remove_alloc(header);
+
+    size = size + sizeof(struct dbmalloc_header);
+    mem = realloc(header, size);
+    if (mem == NULL) {
+        dropbear_exit("m_realloc failed");
+    }
+
+    header = (struct dbmalloc_header*)mem;
+    put_alloc(header);
+    return &mem[sizeof(struct dbmalloc_header)];
+}
+
+void m_free_direct(void* ptr) {
+    struct dbmalloc_header* header = NULL;
+    if (!ptr) {
+        return;
+    }
+    header = get_header(ptr);
+    remove_alloc(header);
+    free(header);
+}
+
+void * m_strdup(const char * str) {
+    char* ret;
+    unsigned int len;
+    len = strlen(str);
+
+    ret = m_malloc(len+1);
+    if (ret == NULL) {
+        dropbear_exit("m_strdup failed");
+    }
+    memcpy(ret, str, len+1);
+    return ret;
+}
+
+