run: add a new "-t" mode for invoking a binary on an allocated TTY

2 files changed, 32 insertions, 5 deletions

diff --git a/src/shared/ptyfwd.c b/src/shared/ptyfwd.c
index 085d374ed8..11356e2def 100644
--- a/src/shared/ptyfwd.c
+++ b/src/shared/ptyfwd.c
@@ -53,6 +53,11 @@ struct PTYForward {
         bool master_writable:1;
         bool master_hangup:1;
 
+        bool repeat:1;
+
+        bool last_char_set:1;
+        char last_char;
+
         char in_buffer[LINE_MAX], out_buffer[LINE_MAX];
         size_t in_buffer_full, out_buffer_full;
 
@@ -169,11 +174,12 @@ static int shovel(PTYForward *f) {
                                  * might be cause by vhangup() or
                                  * temporary closing of everything on
                                  * the other side, we treat it like
-                                 * EAGAIN here and try again. */
+                                 * EAGAIN here and try again, unless
+                                 * repeat is off. */
 
-                                if (errno == EAGAIN || errno == EIO)
+                                if (errno == EAGAIN || (errno == EIO && f->repeat))
                                         f->master_readable = false;
-                                else if (errno == EPIPE || errno == ECONNRESET) {
+                                else if (errno == EPIPE || errno == ECONNRESET || errno == EIO) {
                                         f->master_readable = f->master_writable = false;
                                         f->master_hangup = true;
 
@@ -203,6 +209,12 @@ static int shovel(PTYForward *f) {
                                 }
 
                         } else {
+
+                                if (k > 0) {
+                                        f->last_char = f->out_buffer[k-1];
+                                        f->last_char_set = true;
+                                }
+
                                 assert(f->out_buffer_full >= (size_t) k);
                                 memmove(f->out_buffer, f->out_buffer + k, f->out_buffer_full - k);
                                 f->out_buffer_full -= k;
@@ -285,7 +297,7 @@ static int on_sigwinch_event(sd_event_source *e, const struct signalfd_siginfo *
         return 0;
 }
 
-int pty_forward_new(sd_event *event, int master, PTYForward **ret) {
+int pty_forward_new(sd_event *event, int master, bool repeat, PTYForward **ret) {
         _cleanup_(pty_forward_freep) PTYForward *f = NULL;
         struct winsize ws;
         int r;
@@ -294,6 +306,8 @@ int pty_forward_new(sd_event *event, int master, PTYForward **ret) {
         if (!f)
                 return -ENOMEM;
 
+        f->repeat = repeat;
+
         if (event)
                 f->event = sd_event_ref(event);
         else {
@@ -388,3 +402,14 @@ PTYForward *pty_forward_free(PTYForward *f) {
 
         return NULL;
 }
+
+int pty_forward_last_char(PTYForward *f, char *ch) {
+        assert(f);
+        assert(ch);
+
+        if (!f->last_char_set)
+                return -ENXIO;
+
+        *ch = f->last_char;
+        return 0;
+}
diff --git a/src/shared/ptyfwd.h b/src/shared/ptyfwd.h
index 5a612fd597..d7b658e181 100644
--- a/src/shared/ptyfwd.h
+++ b/src/shared/ptyfwd.h
@@ -28,7 +28,9 @@
 
 typedef struct PTYForward PTYForward;
 
-int pty_forward_new(sd_event *event, int master, PTYForward **f);
+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);
+
 DEFINE_TRIVIAL_CLEANUP_FUNC(PTYForward*, pty_forward_free);