RFC: Stop depending on libsystemd for socket activation

configure.ac

@@ -137,16 +137,6 @@ AC_CHECK_LIB(socket, socket, [LIBS="$LIBS -lsocket"])
 # check for mq_getattr()
 AC_CHECK_LIB(rt, mq_getattr, [LIBS="$LIBS -lrt"])
 
-# check for libsystemd
-AC_ARG_ENABLE(libsystemd,
-	AS_HELP_STRING([--disable-libsystemd], [do not use libsystemd]),
-	[ use_libsystemd="${enableval}" ], [ use_libsystemd="yes" ] )
-AS_IF([test "$use_libsystemd" != "no"],
-	[PKG_CHECK_MODULES(LIBSYSTEMD, libsystemd,,
-		[ AC_MSG_ERROR([install libsystemd-dev or use --disable-libsystemd]) ])
-	AC_DEFINE(USE_LIBSYSTEMD, 1, [Use libsystemd])
-	PCSCLITE_FEATURES="${PCSCLITE_FEATURES} libsystemd"])
-
 # --disable-serial
 AC_ARG_ENABLE(serial,
 	AS_HELP_STRING([--disable-serial], [do not use serial reader.conf files]),
@@ -415,7 +405,6 @@ ATR parsing messages:   ${debugatr}
 ipcdir:                 ${ipcdir}
 use serial:             ${use_serial}
 use usb:                ${use_usb}
-use libsystemd:         ${use_libsystemd}
 systemd unit directory: ${with_systemdsystemunitdir}
 serial config dir.:     ${confdir_exp}
 filter:                 ${use_filter}

src/Makefile.am

@@ -76,9 +76,9 @@ pcscd_SOURCES = \
 	winscard_svc.c \
 	winscard_svc.h
 pcscd_CFLAGS = $(CFLAGS) $(PTHREAD_CFLAGS) $(LIBUSB_CFLAGS) $(LIBUDEV_CFLAGS) \
-	$(POLKIT_CFLAGS) $(LIBSYSTEMD_CFLAGS) \
+	$(POLKIT_CFLAGS) \
 	-DPCSCD -DSIMCLIST_NO_DUMPRESTORE
-pcscd_LDFLAGS = $(LDFLAGS) $(LIBSYSTEMD_LIBS) -export-dynamic
+pcscd_LDFLAGS = $(LDFLAGS) -export-dynamic
 pcscd_LDADD = \
 	$(PTHREAD_LIBS) $(COREFOUNDATION) \
 	$(LIBUSB_LIBS) $(IOKIT) $(LIBUDEV_LIBS) \

src/pcscdaemon.c

@@ -54,9 +54,6 @@ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifdef HAVE_GETOPT_H
 #include <getopt.h>
 #endif
-#ifdef USE_LIBSYSTEMD
-#include <systemd/sd-daemon.h>
-#endif
 
 #include "misc.h"
 #include "pcsclite.h"
@@ -441,11 +438,7 @@ int main(int argc, char **argv)
 		return EXIT_FAILURE;
 	}
 
-#ifdef USE_LIBSYSTEMD
-	/*
-	 * Check if systemd passed us any file descriptors
-	 */
-	rv = sd_listen_fds(0);
+	rv = GetListenFdCount();
 	if (rv > 1)
 	{
 		Log1(PCSC_LOG_CRITICAL, "Too many file descriptors received");
@@ -456,12 +449,11 @@ int main(int argc, char **argv)
 		if (rv == 1)
 		{
 			SocketActivated = true;
-			Log1(PCSC_LOG_INFO, "Started by systemd");
+			Log1(PCSC_LOG_INFO, "Started with socket activation");
 		}
 		else
 			SocketActivated = false;
 	}
-#endif
 
 	/*
 	 * test the presence of /var/run/pcscd/pcscd.comm
@@ -720,11 +712,9 @@ int main(int argc, char **argv)
 	/*
 	 * Initialize the comm structure
 	 */
-#ifdef USE_LIBSYSTEMD
 	if (SocketActivated)
-		rv = ListenExistingSocket(SD_LISTEN_FDS_START + 0);
+		rv = ListenExistingSocket(LISTEN_FDS_START + 0);
 	else
-#endif
 		rv = InitializeSocket();
 
 	if (rv)

src/utils.c

@@ -43,6 +43,7 @@ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <dirent.h>
 #include <fcntl.h>
 #include <pthread.h>
+#include <limits.h>
 
 #include "config.h"
 #include "debuglog.h"
@@ -187,4 +188,40 @@ int ThreadCreate(pthread_t * pthThread, int attributes,
 	pthread_attr_destroy(&attr);
 	return ret;
 }
+
+int GetListenFdCount(void)
+{
+	long long num;
+	char *endptr;
+	const char *envv;
+	int flags;
+
+	envv = getenv("LISTEN_PID");
+        if (envv == NULL)
+		return 0;
+
+	errno = 0;
+	num = strtoll(envv, &endptr, 0);
+	if (errno != 0 || *endptr != '\0' || num != getpid())
+		return 0;
+
+	envv = getenv("LISTEN_FDS");
+	if (envv == NULL)
+		return 0;
+
+	errno = 0;
+	num = strtoll(envv, &endptr, 0);
+	if (errno != 0 || *endptr != '\0' || num < 0 || num > INT_MAX - LISTEN_FDS_START)
+		return 0;
+
+	for (int fd = LISTEN_FDS_START; fd < LISTEN_FDS_START + num; fd++) {
+		flags = fcntl(fd, F_GETFD);
+		if (flags == -1)
+			return -1;
+		if (fcntl(fd, F_SETFD, flags | O_CLOEXEC) == -1)
+			return -1;
+	}
+
+	return num;
+}
 #endif

src/utils.h

@@ -57,6 +57,9 @@ int CheckForOpenCT(void);
 int ThreadCreate(pthread_t *, int, PCSCLITE_THREAD_FUNCTION( ),
 	/*@null@*/ LPVOID);
 
+#define LISTEN_FDS_START 3
+int GetListenFdCount(void);
+
 #endif
 
 #endif

src/winscard_msg_srv.c

@@ -57,9 +57,6 @@ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifdef HAVE_SYS_FILIO_H
 #include <sys/filio.h>
 #endif
-#ifdef USE_LIBSYSTEMD
-#include <systemd/sd-daemon.h>
-#endif
 
 #include "misc.h"
 #include "pcscd.h"
@@ -165,7 +162,6 @@ INTERNAL int32_t InitializeSocket(void)
 	return 0;
 }
 
-#ifdef USE_LIBSYSTEMD
 /**
  * @brief Acquires a socket passed in from systemd.
  *
@@ -180,16 +176,27 @@ INTERNAL int32_t InitializeSocket(void)
  */
 INTERNAL int32_t ListenExistingSocket(int fd)
 {
-	if (!sd_is_socket(fd, AF_UNIX, SOCK_STREAM, -1))
-	{
+	socklen_t sockopt_size, sockaddr_size;
+	struct sockaddr_storage ss;
+	int rv, sockopt;
+
+	sockaddr_size = sizeof ss;
+	rv = getsockname(fd, (struct sockaddr *)&ss, &sockaddr_size);
+	if (rv == -1 || sockaddr_size < sizeof ss.ss_family || ss.ss_family != AF_UNIX) {
 		Log1(PCSC_LOG_CRITICAL, "Passed FD is not an UNIX socket");
 		return -1;
 	}
 
+	sockopt_size = sizeof sockopt;
+	rv = getsockopt(fd, SOL_SOCKET, SO_TYPE, &sockopt, &sockopt_size);
+	if (rv == -1 || sockopt_size != sizeof sockopt || sockopt != SOCK_STREAM) {
+		Log1(PCSC_LOG_CRITICAL, "Passed FD is not a stream type socket");
+		return -1;
+	}
+
 	commonSocket = fd;
 	return 0;
 }
-#endif
 
 /**
  * @brief Looks for messages sent by clients.