init printf: implement %s

2 files changed, 17 insertions, 3 deletions

diff --git a/src/init/main.c b/src/init/main.c
index a819152..7c827eb 100644
--- a/src/init/main.c
+++ b/src/init/main.c
@@ -29,7 +29,7 @@ int main(void) {
 	fs_test();
 	test_await();
 
-	printf("printf test\n");
+	printf("%s\n", "printf test");
 
 	char c;
 	while (_syscall_read(tty_fd, &c, 1, 0))
diff --git a/src/init/stdlib.c b/src/init/stdlib.c
index 56d6da6..876c74c 100644
--- a/src/init/stdlib.c
+++ b/src/init/stdlib.c
@@ -29,8 +29,22 @@ int printf(const char *fmt, ...) {
 		switch (c) {
 			case '\0':
 				// TODO don't assume that stdout is @ fd 0
-				_syscall_write(0, seg, fmt - seg, 0);
-				return total + (fmt - seg);
+				_syscall_write(0, seg, fmt - seg - 1, 0);
+				return total + (fmt - seg - 1);
+
+			case '%':
+				_syscall_write(0, seg, fmt - seg - 1, 0);
+				total += fmt - seg - 1;
+				c = *fmt++;
+				switch (c) {
+					case 's':
+						const char *s = va_arg(argp, char*);
+						_syscall_write(0, s, strlen(s), 0);
+						total += strlen(s);
+						break;
+				}
+				seg = fmt;
+				break;
 		}
 	}
 }