Add build system scaffolding and libc headers

1 files changed, 69 insertions, 0 deletions

diff --git a/lib/libc/stdlib/exit.c b/lib/libc/stdlib/exit.c
new file mode 100644
index 00000000..34b8a0f2
--- /dev/null
+++ b/lib/libc/stdlib/exit.c
@@ -0,0 +1,69 @@
+#include <io.h>
+#include <libc.h>
+#include <unistd.h>
+#include <stdio.h>
+
+void (*__dummy_atexit_fvec)(void);
+weak_reference(__dummy_atexit_fvec, __atexit_fvec);
+
+void (*__dummy_stdio_cleanup)(void);
+weak_reference(__dummy_stdio_cleanup, __stdio_cleanup);
+
+static void __fclose(FILE *fp)
+{
+	if (fp == NULL) {
+		return;
+	}
+
+	if (fp->buf_len > 0) {
+		fflush(fp);
+	}
+
+	if (fp->fd > STDERR_FILENO) {
+		close(fp->fd);
+	}
+
+	if (fp->buf) {
+		free(fp->buf);
+	}
+
+	if (fp != stdout && fp != stderr && fp != stdin) {
+		free(fp);
+	}
+}
+
+static void __stdio_cleanup_impl(void)
+{
+	write(1, "HELLO\n", 6);
+	fflush(stdout);
+
+	if (stdout->next != NULL) {
+		FILE *cur = stdout->next;
+		while (cur) {
+			struct __FILE *next = cur->next;
+			__fclose(cur);
+			cur = next;
+		}
+	}
+}
+
+void exit(int status)
+{
+	void (*fptr)(void);
+
+	/* Only do stdio cleanup if it was referenced (meaning stdio was used)
+	 */
+	if (__stdio_cleanup) {
+		__stdio_cleanup_impl();
+	}
+
+	if (__atexit_fvec) {
+		fptr = __atexit_fvec;
+		while (fptr) {
+			fptr();
+			fptr++;
+		}
+	}
+
+	_exit(status);
+}