machinectl: make sure that "machinectl login" exits immediately when the machine it is connected to dies

5 files changed, 104 insertions, 16 deletions

diff --git a/src/machine/machinectl.c b/src/machine/machinectl.c
index 11f2273e4b..7e995cab68 100644
--- a/src/machine/machinectl.c
+++ b/src/machine/machinectl.c
@@ -1230,16 +1230,42 @@ finish:
         return r;
 }
 
+static int on_machine_removed(sd_bus *bus, sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
+        PTYForward ** forward = (PTYForward**) userdata;
+        int r;
+
+        assert(bus);
+        assert(m);
+        assert(forward);
+
+        if (*forward) {
+                /* If the forwarder is already initialized, tell it to
+                 * exit on the next hangup */
+
+                r = pty_forward_set_repeat(*forward, false);
+                if (r >= 0)
+                        return 0;
+
+                log_error_errno(r, "Failed to set repeat flag: %m");
+        }
+
+        /* On error, or when the forwarder is not initialized yet, quit immediately */
+        sd_event_exit(sd_bus_get_event(bus), EXIT_FAILURE);
+        return 0;
+}
+
 static int login_machine(int argc, char *argv[], void *userdata) {
         _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL;
         _cleanup_bus_message_unref_ sd_bus_message *m = NULL, *reply = NULL;
+        _cleanup_bus_slot_unref_ sd_bus_slot *slot = NULL;
         _cleanup_(pty_forward_freep) PTYForward *forward = NULL;
         _cleanup_event_unref_ sd_event *event = NULL;
         int master = -1, r, ret = 0;
         sd_bus *bus = userdata;
-        const char *pty;
+        const char *pty, *match;
         sigset_t mask;
         char last_char = 0;
+        bool machine_died;
 
         assert(bus);
 
@@ -1257,6 +1283,19 @@ static int login_machine(int argc, char *argv[], void *userdata) {
         if (r < 0)
                 return log_error_errno(r, "Failed to attach bus to event loop: %m");
 
+        match = strappenda("type='signal',"
+                           "sender='org.freedesktop.machine1',"
+                           "path='/org/freedesktop/machine1',",
+                           "interface='org.freedesktop.machine1.Manager',"
+                           "member='MachineRemoved',"
+                           "arg0='",
+                           argv[1],
+                           "'");
+
+        r = sd_bus_add_match(bus, &slot, match, on_machine_removed, &forward);
+        if (r < 0)
+                return log_error_errno(r, "Failed to add machine removal match: %m");
+
         r = sd_bus_message_new_method_call(bus,
                                            &m,
                                            "org.freedesktop.machine1",
@@ -1288,7 +1327,7 @@ static int login_machine(int argc, char *argv[], void *userdata) {
         sigset_add_many(&mask, SIGWINCH, SIGTERM, SIGINT, -1);
         assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
 
-        log_info("Connected to container %s. Press ^] three times within 1s to exit session.", argv[1]);
+        log_info("Connected to machine %s. Press ^] three times within 1s to exit session.", argv[1]);
 
         sd_event_add_signal(event, NULL, SIGINT, NULL, NULL);
         sd_event_add_signal(event, NULL, SIGTERM, NULL, NULL);
@@ -1301,14 +1340,18 @@ static int login_machine(int argc, char *argv[], void *userdata) {
         if (r < 0)
                 return log_error_errno(r, "Failed to run event loop: %m");
 
-        pty_forward_last_char(forward, &last_char);
+        pty_forward_get_last_char(forward, &last_char);
+        machine_died = pty_forward_get_repeat(forward) == 0;
 
         forward = pty_forward_free(forward);
 
         if (last_char != '\n')
                 fputc('\n', stdout);
 
-        log_info("Connection to container %s terminated.", argv[1]);
+        if (machine_died)
+                log_info("Machine %s terminated.", argv[1]);
+        else
+                log_info("Connection to machine %s terminated.", argv[1]);
 
         sd_event_get_exit_code(event, &ret);
         return ret;
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 1ac0a7008c..89bbf2b82c 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -3668,7 +3668,7 @@ int main(int argc, char *argv[]) {
                                 goto finish;
                         }
 
-                        pty_forward_last_char(forward, &last_char);
+                        pty_forward_get_last_char(forward, &last_char);
 
                         forward = pty_forward_free(forward);
 
diff --git a/src/run/run.c b/src/run/run.c
index 22abb0ebbb..d6d0b42d15 100644
--- a/src/run/run.c
+++ b/src/run/run.c
@@ -789,7 +789,7 @@ static int start_transient_service(
                 if (r < 0)
                         return log_error_errno(r, "Failed to run event loop: %m");
 
-                pty_forward_last_char(forward, &last_char);
+                pty_forward_get_last_char(forward, &last_char);
 
                 forward = pty_forward_free(forward);
 
diff --git a/src/shared/ptyfwd.c b/src/shared/ptyfwd.c
index 11356e2def..db2445ceab 100644
--- a/src/shared/ptyfwd.c
+++ b/src/shared/ptyfwd.c
@@ -52,6 +52,7 @@ struct PTYForward {
         bool master_readable:1;
         bool master_writable:1;
         bool master_hangup:1;
+        bool master_suppressed_hangup:1;
 
         bool repeat:1;
 
@@ -170,16 +171,22 @@ static int shovel(PTYForward *f) {
                         k = read(f->master, f->out_buffer + f->out_buffer_full, LINE_MAX - f->out_buffer_full);
                         if (k < 0) {
 
-                                /* Note that EIO on the master device
-                                 * might be cause by vhangup() or
-                                 * temporary closing of everything on
-                                 * the other side, we treat it like
-                                 * EAGAIN here and try again, unless
-                                 * repeat is off. */
+                                if (errno == EAGAIN)
+                                        f->master_readable = false;
+
+                                else if (errno == EIO && f->repeat) {
+
+                                        /* Note that EIO on the master device
+                                         * might be cause by vhangup() or
+                                         * temporary closing of everything on
+                                         * the other side, we treat it like
+                                         * EAGAIN here and try again, unless
+                                         * repeat is off. */
 
-                                if (errno == EAGAIN || (errno == EIO && f->repeat))
                                         f->master_readable = false;
-                                else if (errno == EPIPE || errno == ECONNRESET || errno == EIO) {
+                                        f->master_suppressed_hangup = true;
+
+                                } else if (errno == EPIPE || errno == ECONNRESET || errno == EIO) {
                                         f->master_readable = f->master_writable = false;
                                         f->master_hangup = true;
 
@@ -243,6 +250,8 @@ static int on_master_event(sd_event_source *e, int fd, uint32_t revents, void *u
         assert(fd >= 0);
         assert(fd == f->master);
 
+        f->master_suppressed_hangup = false;
+
         if (revents & (EPOLLIN|EPOLLHUP))
                 f->master_readable = true;
 
@@ -403,7 +412,7 @@ PTYForward *pty_forward_free(PTYForward *f) {
         return NULL;
 }
 
-int pty_forward_last_char(PTYForward *f, char *ch) {
+int pty_forward_get_last_char(PTYForward *f, char *ch) {
         assert(f);
         assert(ch);
 
@@ -413,3 +422,36 @@ int pty_forward_last_char(PTYForward *f, char *ch) {
         *ch = f->last_char;
         return 0;
 }
+
+int pty_forward_set_repeat(PTYForward *f, bool repeat) {
+        int r;
+
+        assert(f);
+
+        if (f->repeat == repeat)
+                return 0;
+
+        f->repeat = repeat;
+
+        /* Are we currently in a suppress hangup phase? If so, let's
+         * immediately terminate things */
+        if (!f->repeat && f->master_suppressed_hangup) {
+
+                /* Let's try to read again from the master fd, and if
+                 * it is this will now cause termination of the
+                 * session. */
+
+                f->master_readable = true;
+                r = shovel(f);
+                if (r < 0)
+                        return r;
+        }
+
+        return 0;
+}
+
+int pty_forward_get_repeat(PTYForward *f) {
+        assert(f);
+
+        return f->repeat;
+}
diff --git a/src/shared/ptyfwd.h b/src/shared/ptyfwd.h
index d7b658e181..d557dee9db 100644
--- a/src/shared/ptyfwd.h
+++ b/src/shared/ptyfwd.h
@@ -31,6 +31,9 @@ typedef struct PTYForward PTYForward;
 int pty_forward_new(sd_event *event, int master, bool repeat, PTYForward **f);
 PTYForward *pty_forward_free(PTYForward *f);
 
-int pty_forward_last_char(PTYForward *f, char *ch);
+int pty_forward_get_last_char(PTYForward *f, char *ch);
+
+int pty_forward_set_repeat(PTYForward *f, bool repeat);
+int pty_forward_get_repeat(PTYForward *f);
 
 DEFINE_TRIVIAL_CLEANUP_FUNC(PTYForward*, pty_forward_free);