1 files changed, 49 insertions, 0 deletions
diff --git a/src/cmd/jsh/builtin.c b/src/cmd/jsh/builtin.c
new file mode 100644
index 0000000..dbcc415
--- /dev/null
+++ b/src/cmd/jsh/builtin.c
@@ -0,0 +1,49 @@
+#include "builtin.h"
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+
+static int shellcd(const size_t n, char * const args[n]);
+
+static const char * const builtins[] = {
+	"cd"
+};
+
+static int (*functions[])(const size_t n, char * const args[n]) = {
+	shellcd
+};
+
+int execbuiltin(size_t index, const size_t n, char * const args[n]) {
+	return (*functions[index])(n, args);
+}
+
+size_t checkbuiltin(const char * const function) {
+	size_t len = sizeof(builtins) / sizeof(builtins[0]);
+	for (size_t i = 0; i < len; i++) {
+		if (strcmp(builtins[i], function) == 0) {
+			return i;
+		}
+	}
+	return -1;
+}
+
+static int shellcd(const size_t n, char * const args[n]) {
+	int status;
+	char *home = getenv("HOME");
+	if (n == 2) {
+		status = chdir(args[1]);
+	} else if (n == 1) {
+		status = chdir(home);
+	} else {
+		errno = E2BIG;
+		status = -1;
+	}
+	if (status != 0) {
+		perror("cd");
+		return EXIT_FAILURE;
+	}
+	return EXIT_SUCCESS;
+}
+