1 files changed, 52 insertions, 0 deletions
diff --git a/src/malloc/oldmalloc/aligned_alloc.c b/src/malloc/oldmalloc/aligned_alloc.c
new file mode 100644
index 00000000..e06c76ed
--- /dev/null
+++ b/src/malloc/oldmalloc/aligned_alloc.c
@@ -0,0 +1,52 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <errno.h>
+#include "malloc_impl.h"
+
+void *aligned_alloc(size_t align, size_t len)
+{
+	unsigned char *mem, *new;
+
+	if ((align & -align) != align) {
+		errno = EINVAL;
+		return 0;
+	}
+
+	if (len > SIZE_MAX - align || __malloc_replaced) {
+		errno = ENOMEM;
+		return 0;
+	}
+
+	if (align <= SIZE_ALIGN)
+		return malloc(len);
+
+	if (!(mem = malloc(len + align-1)))
+		return 0;
+
+	new = (void *)((uintptr_t)mem + align-1 & -align);
+	if (new == mem) return mem;
+
+	struct chunk *c = MEM_TO_CHUNK(mem);
+	struct chunk *n = MEM_TO_CHUNK(new);
+
+	if (IS_MMAPPED(c)) {
+		/* Apply difference between aligned and original
+		 * address to the "extra" field of mmapped chunk. */
+		n->psize = c->psize + (new-mem);
+		n->csize = c->csize - (new-mem);
+		return new;
+	}
+
+	struct chunk *t = NEXT_CHUNK(c);
+
+	/* Split the allocated chunk into two chunks. The aligned part
+	 * that will be used has the size in its footer reduced by the
+	 * difference between the aligned and original addresses, and
+	 * the resulting size copied to its header. A new header and
+	 * footer are written for the split-off part to be freed. */
+	n->psize = c->csize = C_INUSE | (new-mem);
+	n->csize = t->psize -= new-mem;
+
+	__bin_chunk(c);
+	return new;
+}