user: add /initctl for shutting the system down in a cleaner way

1 files changed, 40 insertions, 0 deletions

diff --git a/src/user/app/init/driver/initctl.c b/src/user/app/init/driver/initctl.c
new file mode 100644
index 0000000..b8fbb9b
--- /dev/null
+++ b/src/user/app/init/driver/initctl.c
@@ -0,0 +1,40 @@
+#include "driver.h"
+#include <camellia/syscalls.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+void initctl_drv(handle_t killswitch) {
+	struct fs_wait_response res;
+	char buf[64];
+	const size_t buflen = sizeof buf;
+	while (!_syscall_fs_wait(buf, buflen, &res)) {
+		switch (res.op) {
+			case VFSOP_OPEN:
+				_syscall_fs_respond(NULL, res.len == 0 ? 0 : -1, 0);
+				break;
+			case VFSOP_WRITE:
+				/* null terminate */
+				if (res.len > buflen - 1)
+					res.len = buflen - 1;
+				buf[res.len] = '\0';
+				/* cut at first whitespace */
+				for (size_t i = 0; buf[i]; i++) {
+					if (isspace(buf[i])) {
+						buf[i] = '\0';
+						break;
+					}
+				}
+				if (!strcmp(buf, "halt")) {
+					_syscall_write(killswitch, "halt", 4, 0, 0);
+					exit(1);
+				}
+				_syscall_fs_respond(NULL, res.len, 0);
+				break;
+			default:
+				_syscall_fs_respond(NULL, -ENOSYS, 0);
+				break;
+		}
+	}
+	exit(1);
+}