2 files changed, 110 insertions, 0 deletions

diff --git a/lib/Makefile b/lib/Makefile
index 962470f4962..454396f101b 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -134,6 +134,7 @@ obj-$(CONFIG_OID_REGISTRY) += oid_registry.o
 obj-$(CONFIG_SSCANF) += sscanf.o
 endif
 
+obj-y += abuf.o
 obj-y += date.o
 obj-y += rtc-lib.o
 obj-$(CONFIG_LIB_ELF) += elf.o
diff --git a/lib/abuf.c b/lib/abuf.c
new file mode 100644
index 00000000000..4b17e0b8c0d
--- /dev/null
+++ b/lib/abuf.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Handles a buffer that can be allocated and freed
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <[email protected]>
+ */
+
+#include <common.h>
+#include <abuf.h>
+#include <malloc.h>
+#include <mapmem.h>
+#include <string.h>
+
+void abuf_set(struct abuf *abuf, void *data, size_t size)
+{
+	abuf_uninit(abuf);
+	abuf->data = data;
+	abuf->size = size;
+}
+
+void abuf_map_sysmem(struct abuf *abuf, ulong addr, size_t size)
+{
+	abuf_set(abuf, map_sysmem(addr, size), size);
+}
+
+bool abuf_realloc(struct abuf *abuf, size_t new_size)
+{
+	void *ptr;
+
+	if (!new_size) {
+		/* easy case, just need to uninit, freeing any allocation */
+		abuf_uninit(abuf);
+		return true;
+	} else if (abuf->alloced) {
+		/* currently allocated, so need to reallocate */
+		ptr = realloc(abuf->data, new_size);
+		if (!ptr)
+			return false;
+		abuf->data = ptr;
+		abuf->size = new_size;
+		return true;
+	} else if (new_size <= abuf->size) {
+		/*
+		 * not currently alloced and new size is no larger. Just update
+		 * it. Data is lost off the end if new_size < abuf->size
+		 */
+		abuf->size = new_size;
+		return true;
+	} else {
+		/* not currently allocated and new size is larger. Alloc and
+		 * copy in data. The new space is not inited.
+		 */
+		ptr = memdup(abuf->data, new_size);
+		if (!ptr)
+			return false;
+		abuf->data = ptr;
+		abuf->size = new_size;
+		abuf->alloced = true;
+		return true;
+	}
+}
+
+void *abuf_uninit_move(struct abuf *abuf, size_t *sizep)
+{
+	void *ptr;
+
+	if (sizep)
+		*sizep = abuf->size;
+	if (!abuf->size)
+		return NULL;
+	if (abuf->alloced) {
+		ptr = abuf->data;
+	} else {
+		ptr = memdup(abuf->data, abuf->size);
+		if (!ptr)
+			return NULL;
+	}
+	/* Clear everything out so there is no record of the data */
+	abuf_init(abuf);
+
+	return ptr;
+}
+
+void abuf_init_set(struct abuf *abuf, void *data, size_t size)
+{
+	abuf_init(abuf);
+	abuf_set(abuf, data, size);
+}
+
+void abuf_init_move(struct abuf *abuf, void *data, size_t size)
+{
+	abuf_init_set(abuf, data, size);
+	abuf->alloced = true;
+}
+
+void abuf_uninit(struct abuf *abuf)
+{
+	if (abuf->alloced)
+		free(abuf->data);
+	abuf_init(abuf);
+}
+
+void abuf_init(struct abuf *abuf)
+{
+	abuf->data = NULL;
+	abuf->size = 0;
+	abuf->alloced = false;
+}