Add build system scaffolding and libc headers

1 files changed, 39 insertions, 0 deletions

diff --git a/lib/libc/stdlib/aligned_alloc.c b/lib/libc/stdlib/aligned_alloc.c
new file mode 100644
index 00000000..f978dfa9
--- /dev/null
+++ b/lib/libc/stdlib/aligned_alloc.c
@@ -0,0 +1,39 @@
+#include <errno.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+void *aligned_alloc(size_t alignment, size_t size)
+{
+	if (alignment == 0 || (alignment & (alignment - 1)) != 0) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	if (size % alignment != 0) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	if (size == 0) {
+		return NULL;
+	}
+
+	size_t total_size = size + alignment - 1 + sizeof(void *);
+
+	void *raw_ptr = malloc(total_size);
+	if (raw_ptr == NULL) {
+		errno = ENOMEM;
+		return NULL;
+	}
+
+	uintptr_t raw_addr = (uintptr_t)raw_ptr;
+	uintptr_t aligned_addr = (raw_addr + sizeof(void *) + alignment - 1) &
+				 ~(alignment - 1);
+
+	void **orig_ptr_slot = (void **)(aligned_addr - sizeof(void *));
+	*orig_ptr_slot = raw_ptr;
+
+	return (void *)aligned_addr;
+}