libsystemd-login: add sd_session_get_remote_{host, user}

Makefile-man.am

@@ -908,8 +908,11 @@ MANPAGES_ALIAS += \
 	man/sd_seat_can_multi_session.3 \
 	man/sd_seat_can_tty.3 \
 	man/sd_seat_get_sessions.3 \
+	man/sd_session_is_remote.3 \
 	man/sd_session_get_class.3 \
 	man/sd_session_get_display.3 \
+	man/sd_session_get_remote_host.3 \
+	man/sd_session_get_remote_user.3 \
 	man/sd_session_get_seat.3 \
 	man/sd_session_get_service.3 \
 	man/sd_session_get_state.3 \
@@ -939,8 +942,11 @@ man/sd_seat_can_graphical.3: man/sd_seat_get_active.3
 man/sd_seat_can_multi_session.3: man/sd_seat_get_active.3
 man/sd_seat_can_tty.3: man/sd_seat_get_active.3
 man/sd_seat_get_sessions.3: man/sd_seat_get_active.3
+man/sd_session_is_remote.3: man/sd_session_is_active.3
 man/sd_session_get_class.3: man/sd_session_is_active.3
 man/sd_session_get_display.3: man/sd_session_is_active.3
+man/sd_session_get_remote_host.3: man/sd_session_is_active.3
+man/sd_session_get_remote_user.3: man/sd_session_is_active.3
 man/sd_session_get_seat.3: man/sd_session_is_active.3
 man/sd_session_get_service.3: man/sd_session_is_active.3
 man/sd_session_get_state.3: man/sd_session_is_active.3
@@ -1006,6 +1012,9 @@ man/sd_seat_can_tty.html: man/sd_seat_get_active.html
 man/sd_seat_get_sessions.html: man/sd_seat_get_active.html
 	$(html-alias)
 
+man/sd_session_is_remote.html: man/sd_session_is_active.html
+	$(html-alias)
+
 man/sd_session_get_class.html: man/sd_session_is_active.html
 	$(html-alias)
 
@@ -1021,6 +1030,12 @@ man/sd_session_get_service.html: man/sd_session_is_active.html
 man/sd_session_get_state.html: man/sd_session_is_active.html
 	$(html-alias)
 
+man/sd_session_get_remote_host.html: man/sd_session_is_active.html
+	$(html-alias)
+
+man/sd_session_get_remote_user.html: man/sd_session_is_active.html
+	$(html-alias)
+
 man/sd_session_get_tty.html: man/sd_session_is_active.html
 	$(html-alias)
 

man/sd_session_is_active.xml

@@ -65,6 +65,11 @@
                                 <paramdef>const char* <parameter>session</parameter></paramdef>
                         </funcprototype>
 
+                        <funcprototype>
+                                <funcdef>int <function>sd_session_is_remote</function></funcdef>
+                                <paramdef>const char* <parameter>session</parameter></paramdef>
+                        </funcprototype>
+
                         <funcprototype>
                                 <funcdef>int <function>sd_session_get_state</function></funcdef>
                                 <paramdef>const char* <parameter>session</parameter></paramdef>
@@ -107,6 +112,18 @@
                                 <paramdef>char** <parameter>display</parameter></paramdef>
                         </funcprototype>
 
+                        <funcprototype>
+                                <funcdef>int <function>sd_session_get_remote_host</function></funcdef>
+                                <paramdef>const char* <parameter>session</parameter></paramdef>
+                                <paramdef>char** <parameter>remote_host</parameter></paramdef>
+                        </funcprototype>
+
+                        <funcprototype>
+                                <funcdef>int <function>sd_session_get_remote_user</function></funcdef>
+                                <paramdef>const char* <parameter>session</parameter></paramdef>
+                                <paramdef>char** <parameter>remote_user</parameter></paramdef>
+                        </funcprototype>
+
                         <funcprototype>
                                 <funcdef>int <function>sd_session_get_tty</function></funcdef>
                                 <paramdef>const char* <parameter>session</parameter></paramdef>
@@ -130,6 +147,11 @@
                 (i.e. currently in the foreground and available for
                 user input) or not.</para>
 
+                <para><function>sd_session_is_remote()</function> may
+                be used to determine whether the session identified by
+                the specified session identifier is a remote session
+                (i.e. its remote host is known) or not.</para>
+
                 <para><function>sd_session_get_state()</function> may
                 be used to determine the state of the session
                 identified by the specified session identifier. The
@@ -201,6 +223,23 @@
                 <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
                 call after use.</para>
 
+                <para><function>sd_session_get_remote_host()</function>
+                may be used to determine the remote hostname of the
+                session identified by the specified session
+                identifier. The returned string needs to be
+                freed with the libc
+                <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+                call after use.</para>
+
+                <para><function>sd_session_get_remote_user()</function>
+                may be used to determine the remote username of the
+                session identified by the specified session
+                identifier. The returned string needs to be
+                freed with the libc
+                <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+                call after use. Note that this value is rarely known
+                to the system, and even then should not be relied on.</para>
+
                 <para><function>sd_session_get_tty()</function>
                 may be used to determine the TTY device of the
                 session identified by the specified session
@@ -226,7 +265,8 @@
                 <title>Return Value</title>
 
                 <para>If the test succeeds,
-                <function>sd_session_is_active()</function> returns a
+                <function>sd_session_is_active()</function> and
+                <function>sd_session_is_remote()</function> return a
                 positive integer, if it fails 0.  On success
                 <function>sd_session_get_state()</function>,
                 <function>sd_session_get_uid()</function>,
@@ -234,7 +274,9 @@
                 <function>sd_session_get_service()</function>,
                 <function>sd_session_get_type()</function>,
                 <function>sd_session_get_class()</function>,
-                <function>sd_session_get_display()</function> and
+                <function>sd_session_get_display()</function>,
+                <function>sd_session_get_remote_user()</function>,
+                <function>sd_session_get_remote_host()</function> and
                 <function>sd_session_get_tty()</function> return 0 or
                 a positive integer. On failure, these calls return a
                 negative errno-style error code.</para>
@@ -250,7 +292,9 @@
                 <function>sd_session_get_service()</function>,
                 <function>sd_session_get_type()</function>,
                 <function>sd_session_get_class()</function>,
-                <function>sd_session_get_display()</function> and
+                <function>sd_session_get_display()</function>,
+                <function>sd_session_get_remote_host()</function>,
+                <function>sd_session_get_remote_user()</function> and
                 <function>sd_session_get_tty()</function>
                 interfaces are available as shared library, which can
                 be compiled and linked to with the

src/login/libsystemd-login.sym

@@ -85,3 +85,10 @@ LIBSYSTEMD_LOGIN_207 {
 global:
         sd_session_get_vt;
 } LIBSYSTEMD_LOGIN_205;
+
+LIBSYSTEMD_LOGIN_209 {
+global:
+        sd_session_is_remote;
+        sd_session_get_remote_user;
+        sd_session_get_remote_host;
+} LIBSYSTEMD_LOGIN_207;

src/login/sd-login.c

@@ -254,6 +254,26 @@ _public_ int sd_session_is_active(const char *session) {
         return r;
 }
 
+_public_ int sd_session_is_remote(const char *session) {
+        int r;
+        _cleanup_free_ char *p = NULL, *s = NULL;
+
+        r = file_of_session(session, &p);
+        if (r < 0)
+                return r;
+
+        r = parse_env_file(p, NEWLINE, "REMOTE", &s, NULL);
+        if (r < 0)
+                return r;
+
+        if (!s)
+                return -EIO;
+
+        r = parse_boolean(s);
+
+        return r;
+}
+
 _public_ int sd_session_get_state(const char *session, char **state) {
         _cleanup_free_ char *p = NULL, *s = NULL;
         int r;
@@ -364,6 +384,14 @@ _public_ int sd_session_get_display(const char *session, char **display) {
         return session_get_string(session, "DISPLAY", display);
 }
 
+_public_ int sd_session_get_remote_user(const char *session, char **remote_user) {
+        return session_get_string(session, "REMOTE_USER", remote_user);
+}
+
+_public_ int sd_session_get_remote_host(const char *session, char **remote_host) {
+        return session_get_string(session, "REMOTE_HOST", remote_host);
+}
+
 static int file_of_seat(const char *seat, char **_p) {
         char *p;
         int r;

src/login/test-login.c

@@ -30,7 +30,7 @@
 static void test_login(void) {
         int r, k;
         uid_t u, u2;
-        char *seat, *type, *class, *display;
+        char *seat, *type, *class, *display, *remote_user, *remote_host;
         char *session;
         char *state;
         char *session2;
@@ -71,6 +71,10 @@ static void test_login(void) {
         assert_se(r >= 0);
         printf("active = %s\n", yes_no(r));
 
+        r = sd_session_is_remote(session);
+        assert_se(r >= 0);
+        printf("remote = %s\n", yes_no(r));
+
         r = sd_session_get_state(session, &state);
         assert_se(r >= 0);
         printf("state = %s\n", state);
@@ -92,6 +96,14 @@ static void test_login(void) {
         printf("display = %s\n", display);
         free(display);
 
+        assert_se(sd_session_get_remote_user(session, &remote_user) >= 0);
+        printf("remote_user = %s\n", remote_user);
+        free(remote_user);
+
+        assert_se(sd_session_get_remote_host(session, &remote_host) >= 0);
+        printf("remote_host = %s\n", remote_host);
+        free(remote_host);
+
         assert_se(sd_session_get_seat(session, &seat) >= 0);
         printf("seat = %s\n", seat);
 

src/systemd/sd-login.h

@@ -95,9 +95,12 @@ int sd_uid_get_sessions(uid_t uid, int require_active, char ***sessions);
  * just return number of seats.*/
 int sd_uid_get_seats(uid_t uid, int require_active, char ***seats);
 
-/* Return 1 if the session is a active. */
+/* Return 1 if the session is active. */
 int sd_session_is_active(const char *session);
 
+/* Return 1 if the session is remote. */
+int sd_session_is_remote(const char *session);
+
 /* Get state from session. Possible states: online, active, closing
  * (This function is a more generic version of
  * sd_session_is_active().) */
@@ -121,6 +124,12 @@ int sd_session_get_class(const char *session, char **clazz);
 /* Determine the X11 display of this session. */
 int sd_session_get_display(const char *session, char **display);
 
+/* Determine the remote host of this session. */
+int sd_session_get_remote_host(const char *session, char **remote_host);
+
+/* Determine the remote user of this session (if provided by PAM). */
+int sd_session_get_remote_user(const char *session, char **remote_user);
+
 /* Determine the TTY of this session. */
 int sd_session_get_tty(const char *session, char **display);