1 files changed, 179 insertions, 0 deletions
diff --git a/src/lib/mempool.h b/src/lib/mempool.h
new file mode 100644
index 0000000..9c7aca0
--- /dev/null
+++ b/src/lib/mempool.h
@@ -0,0 +1,179 @@
+#ifndef MEMPOOL_H
+#define MEMPOOL_H
+
+#include "macros.h"
+
+/* When DEBUG is enabled, Dovecot warns whenever a memory pool is grown.
+   This is done so that the initial pool size could be set large enough so that
+   it wouldn't grow in normal use. For some memory pools it's too difficult
+   to calculate a good initial size, so this prefix should be used with those
+   pools to disable the warning. */
+#define MEMPOOL_GROWING "GROWING-"
+
+/* The maximum allocation size that's allowed.  Anything larger than that
+   will panic.  No pool ever should need more than 4kB of overhead per
+   allocation. */
+#define POOL_MAX_ALLOC_SIZE	(SSIZE_T_MAX - 4096)
+
+/* Memory allocated and reallocated (the new data in it) in pools is always
+   zeroed, it will cost only a few CPU cycles and may well save some debug
+   time. */
+
+typedef struct pool *pool_t;
+
+struct pool_vfuncs {
+	const char *(*get_name)(pool_t pool);
+
+	void (*ref)(pool_t pool);
+	void (*unref)(pool_t *pool);
+
+	void *(*malloc)(pool_t pool, size_t size) ATTR_RETURNS_NONNULL;
+	void (*free)(pool_t pool, void *mem);
+
+	/* memory in old_size..new_size will be zeroed */
+	void *(*realloc)(pool_t pool, void *mem,
+			 size_t old_size, size_t new_size)
+		ATTR_WARN_UNUSED_RESULT ATTR_RETURNS_NONNULL;
+
+	/* Frees all the memory in pool. NOTE: system_pool doesn't support
+	   this and crashes if it's used */
+	void (*clear)(pool_t pool);
+
+	/* Returns the maximum amount of bytes that can be allocated with
+	   minimal trouble. If there's no such concept, always returns 0. */
+	size_t (*get_max_easy_alloc_size)(pool_t pool);
+};
+
+struct pool {
+	const struct pool_vfuncs *v;
+
+	bool alloconly_pool:1;
+	bool datastack_pool:1;
+};
+
+/* system_pool uses calloc() + realloc() + free() */
+extern pool_t system_pool;
+extern struct pool static_system_pool;
+
+/* memory allocated from data_stack is valid only until next t_pop() call.
+   No checks are performed. */
+extern pool_t unsafe_data_stack_pool;
+
+/* Create a new alloc-only pool. Note that `size' specifies the initial
+   malloc()ed block size, part of it is used internally. */
+pool_t pool_alloconly_create(const char *name, size_t size);
+/* Like alloconly pool, but clear the memory before freeing it. The idea is
+   that you could allocate memory for storing sensitive information from this
+   pool, and be sure that it gets cleared from the memory when it's no longer
+   needed. */
+pool_t pool_alloconly_create_clean(const char *name, size_t size);
+
+/* When allocating memory from returned pool, the data stack frame must be
+   the same as it was when calling this function. pool_unref() also checks
+   that the stack frame is the same. This should make it quite safe to use. */
+pool_t pool_datastack_create(void);
+
+/* Create new alloc pool. This is very similar to system pool, but it
+   will deallocate all memory on deinit. */
+pool_t pool_allocfree_create(const char *name);
+
+/* Like alloc pool, but all memory is cleaned before freeing.
+   See pool_alloconly_create_clean. */
+pool_t pool_allocfree_create_clean(const char *name);
+
+/* Similar to nearest_power(), but try not to exceed buffer's easy
+   allocation size. If you don't have any explicit minimum size, use
+   old_size + 1. */
+size_t pool_get_exp_grown_size(pool_t pool, size_t old_size, size_t min_size);
+
+/* We require sizeof(type) to be <= UINT_MAX. This allows compiler to optimize
+   away the entire MALLOC_MULTIPLY() call on 64bit systems. */
+#define p_new(pool, type, count) \
+	((type *) p_malloc(pool, MALLOC_MULTIPLY((unsigned int)sizeof(type), (count))) + \
+	 COMPILE_ERROR_IF_TRUE(sizeof(type) > UINT_MAX))
+
+#define p_realloc_type(pool, mem, type, old_count, new_count) \
+	((type *) p_realloc(pool, mem, \
+	 MALLOC_MULTIPLY((unsigned int)sizeof(type), (old_count)), \
+	 MALLOC_MULTIPLY((unsigned int)sizeof(type), (new_count))) + \
+		COMPILE_ERROR_IF_TRUE(sizeof(type) > UINT_MAX))
+
+static inline void * ATTR_MALLOC ATTR_RETURNS_NONNULL
+p_malloc(pool_t pool, size_t size)
+{
+	if (unlikely(size == 0 || size > POOL_MAX_ALLOC_SIZE))
+		i_panic("Trying to allocate %zu bytes", size);
+
+	return pool->v->malloc(pool, size);
+}
+
+static inline void * ATTR_WARN_UNUSED_RESULT ATTR_RETURNS_NONNULL
+p_realloc(pool_t pool, void *mem, size_t old_size, size_t new_size)
+{
+	if (unlikely(new_size == 0 || new_size > POOL_MAX_ALLOC_SIZE))
+		i_panic("Trying to reallocate %zu -> %zu bytes",
+			old_size, new_size);
+
+	if (mem == NULL)
+		return pool->v->malloc(pool, new_size);
+
+	return pool->v->realloc(pool, mem, old_size, new_size);
+}
+
+/* Free the memory. p_free() and p_free_and_null() are now guaranteed to both
+   set mem=NULL, so either one of them can be used. */
+#define p_free(pool, mem) \
+	STMT_START { \
+		p_free_internal(pool, mem);	\
+		(mem) = NULL;			\
+	} STMT_END
+#define p_free_and_null(pool, mem) p_free(pool, mem)
+
+static inline void p_free_internal(pool_t pool, void *mem)
+{
+	if (mem != NULL)
+		pool->v->free(pool, mem);
+}
+
+static inline void p_clear(pool_t pool)
+{
+	pool->v->clear(pool);
+}
+
+static inline size_t p_get_max_easy_alloc_size(pool_t pool)
+{
+	return pool->v->get_max_easy_alloc_size(pool);
+}
+
+static inline const char *pool_get_name(pool_t pool)
+{
+	return pool->v->get_name(pool);
+}
+
+static inline void pool_ref(pool_t pool)
+{
+	pool->v->ref(pool);
+}
+
+static inline void pool_unref(pool_t *pool)
+{
+	if (*pool != NULL)
+		(*pool)->v->unref(pool);
+}
+
+/* These functions are only for pools created with pool_alloconly_create(): */
+
+/* Returns how much memory has been allocated from this pool. */
+size_t pool_alloconly_get_total_used_size(pool_t pool);
+/* Returns how much system memory has been allocated for this pool. */
+size_t pool_alloconly_get_total_alloc_size(pool_t pool);
+
+/* Returns how much memory has been allocated from this pool. */
+size_t pool_allocfree_get_total_used_size(pool_t pool);
+/* Returns how much system memory has been allocated for this pool. */
+size_t pool_allocfree_get_total_alloc_size(pool_t pool);
+
+/* private: */
+void pool_system_free(pool_t pool, void *mem);
+
+#endif