sulogin: agetty: use the plymouth local protocol instead the plymouth binary

for stopping plymouthd.  That do not depend on the existence of
the plymouth binary if it e.g. becomes uninstalled or an other
service is providing plymouthd facilities.

[kzak@redhat.com: - fix compiler warnings [-Wpointer-sign]
                  - use sizeof() for write_all()
                  - cast to char* for read_all]

Signed-off-by: Werner Fink <werner@suse.de>
Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 147 insertions, 0 deletions

diff --git a/lib/plymouth-ctrl.c b/lib/plymouth-ctrl.c
new file mode 100644
index 000000000..2a1b2ce3e
--- /dev/null
+++ b/lib/plymouth-ctrl.c
@@ -0,0 +1,147 @@
+/*
+ * plymouth-ctrl.c	Simply communcations with plymouthd
+ *			to avoid forked sub processes and/or
+ *			misssed plymouth send commands tool
+ *			due a plymouthd replacment.
+ *
+ * Copyright (c) 2016 SUSE Linux GmbH, All rights reserved.
+ * Copyright (c) 2016 Werner Fink <werner@suse.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (see the file COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ *
+ * Author: Werner Fink <werner@suse.de>
+ */
+
+#include <errno.h>
+#include <limits.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+#include "all-io.h"
+#include "c.h"
+#include "nls.h"
+#include "plymouth-ctrl.h"
+
+static int can_read(int fd, const long timeout)
+{
+	struct pollfd fds = {
+		.fd = fd,
+		.events = POLLIN|POLLPRI,
+		.revents = 0,
+	};
+	int ret;
+
+	do {
+		ret = poll(&fds, 1, timeout);
+	} while ((ret < 0) && (errno == EINTR));
+
+	return (ret == 1) && (fds.revents & (POLLIN|POLLPRI));
+}
+
+static int open_un_socket_and_connect(void)
+{
+	struct sockaddr_un su = {		/* The abstract UNIX socket of plymouth */
+		.sun_family = AF_UNIX,
+		.sun_path = PLYMOUTH_SOCKET_PATH,
+	};
+	const int one = 1;
+	int fd, ret;
+
+	fd = socket(PF_UNIX, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+	if (fd < 0) {
+		warnx(_("can not open UNIX socket"));
+		goto err;
+	}
+
+	ret = setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &one, (socklen_t)sizeof(one));
+	if (ret < 0) {
+		warnx(_("can not set option for UNIX socket"));
+		close(fd);
+		fd = -1;
+		goto err;
+	}
+
+	/*
+	 * Please note that the PLYMOUTH_SOCKET_PATH has a
+	 * leading NULL byte to mark it as an abstract socket
+	 */
+	ret = connect(fd, &su, offsetof(struct sockaddr_un, sun_path) + 1 + strlen(su.sun_path+1));
+	if (ret < 0) {
+		if (errno != ECONNREFUSED)
+			warnx(_("can not connect on UNIX socket"));
+		close(fd);
+		fd = -1;
+		goto err;
+	}
+err:
+	return fd;
+}
+
+int plymouth_command(int cmd, ...)
+{
+	uint8_t answer[2], command[2];
+	struct sigaction sp, op;
+	int fdsock = -1, ret = 0;
+
+	sigemptyset (&sp.sa_mask);
+	sp.sa_handler = SIG_IGN;
+	sp.sa_flags = SA_RESTART;
+	sigaction(SIGPIPE, &sp, &op);
+
+	/*
+	 * The plymouthd does read at least two bytes.
+	 */
+	command[1] = '\0';
+	switch (cmd) {
+	case MAGIC_PING:
+		fdsock = open_un_socket_and_connect();
+		if (fdsock >= 0) {
+			command[0] = cmd;
+			write_all(fdsock, command, sizeof(command));
+		}
+		break;
+	case MAGIC_QUIT:
+		fdsock = open_un_socket_and_connect();
+		if (fdsock >= 0) {
+			command[0] = cmd;
+			write_all(fdsock, command, sizeof(command));
+		}
+		break;
+	default:
+		warnx(_("the plymouth request %c is not implemented"), cmd);
+	case '?':
+		goto err;
+	}
+
+	answer[0] = '\0';
+	if (fdsock >= 0) {
+		if (can_read(fdsock, 1000))
+			read_all(fdsock, (char *) &answer[0], sizeof(answer));
+		close(fdsock);
+	}
+	sigaction(SIGPIPE, &op, NULL);
+	ret = (answer[0] == ANSWER_ACK) ? 1 : 0;
+err:
+	return ret;
+}
+