1 files changed, 89 insertions, 0 deletions
diff --git a/src/cmd/login/login.c b/src/cmd/login/login.c
new file mode 100644
index 0000000..0f9e8b7
--- /dev/null
+++ b/src/cmd/login/login.c
@@ -0,0 +1,89 @@
+#include <camellia/flags.h>
+#include <camellia/syscalls.h>
+#include <ctype.h>
+#include <errno.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <camellia/fs/misc.h>
+
+static const char *shell = "/bin/shell";
+
+static void cutspace(char *s) {
+	for (; *s; s++) {
+		if (isspace(*s)) {
+			*s = '\0';
+			break;
+		}
+	}
+}
+
+static bool segcmp(const char *path, int idx, const char *s2) {
+	if (idx < 0) return false;
+	while (idx > 0) {
+		if (*path == '\0') return false;
+		if (*path == '/') idx--;
+		path++;
+	}
+	/* path is at the start of the selected segment */
+	while (*s2 && *path++ == *s2++);
+	return (*path == '\0' || *path == '/') && *s2 == '\0';
+}
+
+static void drv(const char *user) {
+	char *buf = malloc(PATH_MAX);
+	for (;;) {
+		struct ufs_request req;
+		hid_t reqh = ufs_wait(buf, PATH_MAX, &req);
+		if (reqh < 0) break;
+		switch (req.op) {
+			case VFSOP_OPEN:
+				if (segcmp(buf, 1, "Users") && segcmp(buf, 2, user)) { //  /Users/$user/**
+					forward_open(reqh, buf, req.len, req.flags);
+				} else if (segcmp(buf, 1, "Users") && segcmp(buf, 3, "private")) { //  /Users/*/private/**
+					_sys_fs_respond(reqh, NULL, -EACCES, 0);
+				} else if (!OPEN_WRITEABLE(req.flags)) {
+					forward_open(reqh, buf, req.len, req.flags);
+				} else {
+					_sys_fs_respond(reqh, NULL, -EACCES, 0);
+				}
+				break;
+
+			default:
+				_sys_fs_respond(reqh, NULL, -1, 0);
+				break;
+		}
+	}
+	free(buf);
+}
+
+static void trylogin(const char *user) {
+	if (strcmp(user, "root") != 0) {
+		char buf[128];
+		snprintf(buf, sizeof buf, "/Users/%s/", user);
+		if (chdir(buf) < 0) {
+			printf("no such user: %s\n", user);
+			return;
+		}
+		MOUNT_AT("/") { drv(user); }
+	}
+
+	execv(shell, NULL);
+	fprintf(stderr, "login: couldn't launch %s\n", shell);
+	exit(1);
+}
+
+int main(void) {
+	char user[64];
+	printf("\nCamellia\n");
+	for (;;) {
+		printf("login: ");
+		fgets(user, sizeof user, stdin);
+		if (ferror(stdin)) return -1;
+
+		cutspace(user);
+		if (user[0]) trylogin(user);
+	}
+}