device: implement access control to the boards

Limit access control to the boards according to the passed username. If
the user has no access, the board becoms completely invisible: it is not
listed, it is not possible to fetch board description, etc.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

cdba-server.c

@@ -47,6 +47,7 @@
 #include "list.h"
 
 static bool quit_invoked;
+static const char *username;
 
 struct device *selected_device;
 
@@ -121,7 +122,7 @@ static void msg_select_board(const void *param)
 {
 	struct msg reply = { MSG_SELECT_BOARD, 0 };
 
-	selected_device = device_open(param, &fastboot_ops);
+	selected_device = device_open(param, username, &fastboot_ops);
 	if (!selected_device) {
 		fprintf(stderr, "failed to open %s\n", (const char *)param);
 		quit_invoked = true;
@@ -231,10 +232,10 @@ static int handle_stdin(int fd, void *buf)
 			device_send_break(selected_device);
 			break;
 		case MSG_LIST_DEVICES:
-			device_list_devices();
+			device_list_devices(username);
 			break;
 		case MSG_BOARD_INFO:
-			device_info(msg->data, msg->len);
+			device_info(username, msg->data, msg->len);
 			break;
 		default:
 			fprintf(stderr, "unk %d len %d\n", msg->type, msg->len);
@@ -364,6 +365,8 @@ int main(int argc, char **argv)
 
 	signal(SIGPIPE, sigpipe_handler);
 
+	username = getenv("CDBA_USER");
+
 	ret = device_parser(".cdba");
 	if (ret) {
 		ret = device_parser("/etc/cdba");

device.c

@@ -83,7 +83,27 @@ static void device_lock(struct device *device)
 		err(1, "failed to lock lockfile %s", lock);
 }
 
+static bool device_check_access(struct device *device,
+				const char *username)
+{
+	struct device_user *user;
+
+	if (!device->users)
+		return true;
+
+	if (!username)
+		return false;
+
+	list_for_each_entry(user, device->users, node) {
+		if (!strcmp(user->username, username))
+			return true;
+	}
+
+	return false;
+}
+
 struct device *device_open(const char *board,
+			   const char *username,
 			   struct fastboot_ops *fastboot_ops)
 {
 	struct device *device;
@@ -98,6 +118,9 @@ struct device *device_open(const char *board,
 found:
 	assert(device->open || device->console_dev);
 
+	if (!device_check_access(device, username))
+		return NULL;
+
 	device_lock(device);
 
 	if (device->open) {
@@ -269,7 +292,7 @@ void device_send_break(struct device *device)
 		device->send_break(device);
 }
 
-void device_list_devices(void)
+void device_list_devices(const char *username)
 {
 	struct device *device;
 	struct msg hdr;
@@ -277,6 +300,9 @@ void device_list_devices(void)
 	char buf[80];
 
 	list_for_each_entry(device, &devices, node) {
+		if (!device_check_access(device, username))
+			continue;
+
 		if (device->name)
 			len = snprintf(buf, sizeof(buf), "%-20s %s", device->board, device->name);
 		else
@@ -293,7 +319,7 @@ void device_list_devices(void)
 	write(STDOUT_FILENO, &hdr, sizeof(hdr));
 }
 
-void device_info(const void *data, size_t dlen)
+void device_info(const char *username, const void *data, size_t dlen)
 {
 	struct device *device;
 	struct msg hdr;
@@ -301,7 +327,13 @@ void device_info(const void *data, size_t dlen)
 	size_t len = 0;
 
 	list_for_each_entry(device, &devices, node) {
-		if (!strncmp(device->board, data, dlen) && device->description) {
+		if (strncmp(device->board, data, dlen))
+			continue;
+
+		if (!device_check_access(device, username))
+			continue;
+
+		if (device->description) {
 			description = device->description;
 			len = strlen(device->description);
 			break;

device.h

@@ -15,6 +15,7 @@ struct device {
 	char *name;
 	char *serial;
 	char *description;
+	struct list_head *users;
 	unsigned voltage;
 	bool tickle_mmc;
 	bool usb_always_on;
@@ -45,9 +46,17 @@ struct device {
 	struct list_head node;
 };
 
+struct device_user {
+	const char *username;
+
+	struct list_head node;
+};
+
 void device_add(struct device *device);
 
-struct device *device_open(const char *board, struct fastboot_ops *fastboot_ops);
+struct device *device_open(const char *board,
+			   const char *username,
+			   struct fastboot_ops *fastboot_ops);
 void device_close(struct device *dev);
 int device_power(struct device *device, bool on);
 
@@ -60,8 +69,8 @@ void device_boot(struct device *device, const void *data, size_t len);
 void device_fastboot_boot(struct device *device);
 void device_fastboot_flash_reboot(struct device *device);
 void device_send_break(struct device *device);
-void device_list_devices(void);
-void device_info(const void *data, size_t dlen);
+void device_list_devices(const char *username);
+void device_info(const char *username, const void *data, size_t dlen);
 
 enum {
 	DEVICE_KEY_FASTBOOT,

device_parser.c

@@ -90,6 +90,28 @@ static void parse_board(struct device_parser *dp)
 	dev = calloc(1, sizeof(*dev));
 
 	while (accept(dp, YAML_SCALAR_EVENT, key)) {
+		if (!strcmp(key, "users")) {
+			dev->users = calloc(1, sizeof(*dev->users));
+			list_init(dev->users);
+
+			if (accept(dp, YAML_SCALAR_EVENT, value))
+				continue;
+
+			expect(dp, YAML_SEQUENCE_START_EVENT, NULL);
+
+			while (accept(dp, YAML_SCALAR_EVENT, key)) {
+				struct device_user *user = calloc(1, sizeof(*user));
+
+				user->username = strdup(key);
+
+				list_add(dev->users, &user->node);
+			}
+
+			expect(dp, YAML_SEQUENCE_END_EVENT, NULL);
+
+			continue;
+		}
+
 		expect(dp, YAML_SCALAR_EVENT, value);
 
 		if (!strcmp(key, "board")) {