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From 98e5c02b1602eaaac5c63045fa7a06e40249445e Mon Sep 17 00:00:00 2001
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From: Lennart Poettering <lennart@poettering.net>
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Date: Wed, 18 Feb 2015 23:32:55 +0100
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Subject: [PATCH] nspawn: when connected to pipes for stdin/stdout, pass them
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 as-is to PID 1
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Previously we always invoked the container PID 1 on /dev/console of the
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container. With this change we do so only if nspawn was invoked
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interactively (i.e. its stdin/stdout was connected to a TTY). In all other
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cases we directly pass through the fds unmodified.
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This has the benefit that nspawn can be added into shell pipelines.
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https://bugs.freedesktop.org/show_bug.cgi?id=87732
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Cherry-picked from: 9c857b9d160c10b4454fc9f83442c1878343422f
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Resolves: #1307080
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---
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 src/machine/machinectl.c |  2 +-
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 src/nspawn/nspawn.c      | 48 +++++++++++++++++--------------
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 src/run/run.c            |  2 +-
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 src/shared/ptyfwd.c      | 75 ++++++++++++++++++++++++++++--------------------
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 src/shared/ptyfwd.h      |  2 +-
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 5 files changed, 74 insertions(+), 55 deletions(-)
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diff --git a/src/machine/machinectl.c b/src/machine/machinectl.c
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index cfd3162fb..1a58aeaf1 100644
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--- a/src/machine/machinectl.c
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+++ b/src/machine/machinectl.c
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@@ -1427,7 +1427,7 @@ static int login_machine(int argc, char *argv[], void *userdata) {
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         sd_event_add_signal(event, NULL, SIGINT, NULL, NULL);
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         sd_event_add_signal(event, NULL, SIGTERM, NULL, NULL);
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-        r = pty_forward_new(event, master, true, &forward);
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+        r = pty_forward_new(event, master, true, false, &forward);
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         if (r < 0)
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                 return log_error_errno(r, "Failed to create PTY forwarder: %m");
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diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
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index 78bd58483..a37b64094 100644
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--- a/src/nspawn/nspawn.c
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+++ b/src/nspawn/nspawn.c
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@@ -3581,6 +3581,7 @@ int main(int argc, char *argv[]) {
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         int ret = EXIT_SUCCESS;
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         union in_addr_union exposed = {};
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         _cleanup_release_lock_file_ LockFile tree_global_lock = LOCK_FILE_INIT, tree_local_lock = LOCK_FILE_INIT;
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+        bool interactive;
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         log_parse_environment();
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         log_open();
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@@ -3754,6 +3755,8 @@ int main(int argc, char *argv[]) {
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                         goto finish;
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         }
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+        interactive = isatty(STDIN_FILENO) > 0 && isatty(STDOUT_FILENO) > 0;
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+
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         master = posix_openpt(O_RDWR|O_NOCTTY|O_CLOEXEC|O_NDELAY);
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         if (master < 0) {
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                 r = log_error_errno(errno, "Failed to acquire pseudo tty: %m");
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@@ -3766,15 +3769,15 @@ int main(int argc, char *argv[]) {
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                 goto finish;
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         }
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-        if (!arg_quiet)
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-                log_info("Spawning container %s on %s.\nPress ^] three times within 1s to kill container.",
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-                         arg_machine, arg_image ?: arg_directory);
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-
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         if (unlockpt(master) < 0) {
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                 r = log_error_errno(errno, "Failed to unlock tty: %m");
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                 goto finish;
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         }
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+        if (!arg_quiet)
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+                log_info("Spawning container %s on %s.\nPress ^] three times within 1s to kill container.",
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+                         arg_machine, arg_image ?: arg_directory);
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+
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         assert_se(sigemptyset(&mask) == 0);
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         sigset_add_many(&mask, SIGCHLD, SIGWINCH, SIGTERM, SIGINT, -1);
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         assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
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@@ -3860,9 +3863,6 @@ int main(int argc, char *argv[]) {
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                         master = safe_close(master);
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-                        close_nointr(STDIN_FILENO);
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-                        close_nointr(STDOUT_FILENO);
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-                        close_nointr(STDERR_FILENO);
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                         kmsg_socket_pair[0] = safe_close(kmsg_socket_pair[0]);
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                         rtnl_socket_pair[0] = safe_close(rtnl_socket_pair[0]);
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@@ -3870,21 +3870,27 @@ int main(int argc, char *argv[]) {
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                         reset_all_signal_handlers();
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                         reset_signal_mask();
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-                        r = open_terminal(console, O_RDWR);
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-                        if (r != STDIN_FILENO) {
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-                                if (r >= 0) {
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-                                        safe_close(r);
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-                                        r = -EINVAL;
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-                                }
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+                        if (interactive) {
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+                                close_nointr(STDIN_FILENO);
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+                                close_nointr(STDOUT_FILENO);
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+                                close_nointr(STDERR_FILENO);
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-                                log_error_errno(r, "Failed to open console: %m");
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-                                _exit(EXIT_FAILURE);
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-                        }
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+                                r = open_terminal(console, O_RDWR);
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+                                if (r != STDIN_FILENO) {
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+                                        if (r >= 0) {
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+                                                safe_close(r);
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+                                                r = -EINVAL;
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+                                        }
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-                        if (dup2(STDIN_FILENO, STDOUT_FILENO) != STDOUT_FILENO ||
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-                            dup2(STDIN_FILENO, STDERR_FILENO) != STDERR_FILENO) {
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-                                log_error_errno(errno, "Failed to duplicate console: %m");
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-                                _exit(EXIT_FAILURE);
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+                                        log_error_errno(r, "Failed to open console: %m");
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+                                        _exit(EXIT_FAILURE);
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+                                }
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+
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+                                if (dup2(STDIN_FILENO, STDOUT_FILENO) != STDOUT_FILENO ||
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+                                    dup2(STDIN_FILENO, STDERR_FILENO) != STDERR_FILENO) {
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+                                        log_error_errno(errno, "Failed to duplicate console: %m");
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+                                        _exit(EXIT_FAILURE);
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+                                }
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                         }
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                         if (setsid() < 0) {
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@@ -4227,7 +4233,7 @@ int main(int argc, char *argv[]) {
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                                 rtnl_socket_pair[0] = safe_close(rtnl_socket_pair[0]);
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-                                r = pty_forward_new(event, master, true, &forward);
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+                                r = pty_forward_new(event, master, true, !interactive, &forward);
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                                 if (r < 0) {
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                                         log_error_errno(r, "Failed to create PTY forwarder: %m");
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                                         goto finish;
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diff --git a/src/run/run.c b/src/run/run.c
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index dd1338f3b..468034284 100644
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--- a/src/run/run.c
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+++ b/src/run/run.c
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@@ -780,7 +780,7 @@ static int start_transient_service(
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                 if (!arg_quiet)
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                         log_info("Running as unit %s.\nPress ^] three times within 1s to disconnect TTY.", service);
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-                r = pty_forward_new(event, master, false, &forward);
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+                r = pty_forward_new(event, master, false, false, &forward);
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                 if (r < 0)
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                         return log_error_errno(r, "Failed to create PTY forwarder: %m");
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diff --git a/src/shared/ptyfwd.c b/src/shared/ptyfwd.c
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index 88b3f4e3c..4402af123 100644
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--- a/src/shared/ptyfwd.c
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+++ b/src/shared/ptyfwd.c
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@@ -42,6 +42,8 @@ struct PTYForward {
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         struct termios saved_stdin_attr;
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         struct termios saved_stdout_attr;
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+        bool read_only:1;
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+
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         bool saved_stdin:1;
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         bool saved_stdout:1;
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@@ -298,7 +300,13 @@ static int on_sigwinch_event(sd_event_source *e, const struct signalfd_siginfo *
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         return 0;
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 }
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-int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward **ret) {
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+int pty_forward_new(
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+                sd_event *event,
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+                int master,
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+                bool ignore_vhangup,
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+                bool read_only,
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+                PTYForward **ret) {
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+
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         _cleanup_(pty_forward_freep) PTYForward *f = NULL;
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         struct winsize ws;
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         int r;
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@@ -307,6 +315,7 @@ int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward
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         if (!f)
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                 return -ENOMEM;
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+        f->read_only = read_only;
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         f->ignore_vhangup = ignore_vhangup;
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         if (event)
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@@ -317,13 +326,15 @@ int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward
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                         return r;
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         }
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-        r = fd_nonblock(STDIN_FILENO, true);
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-        if (r < 0)
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-                return r;
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+        if (!read_only) {
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+                r = fd_nonblock(STDIN_FILENO, true);
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+                if (r < 0)
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+                        return r;
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-        r = fd_nonblock(STDOUT_FILENO, true);
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-        if (r < 0)
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-                return r;
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+                r = fd_nonblock(STDOUT_FILENO, true);
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+                if (r < 0)
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+                        return r;
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+        }
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         r = fd_nonblock(master, true);
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         if (r < 0)
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@@ -334,36 +345,34 @@ int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward
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         if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0)
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                 (void)ioctl(master, TIOCSWINSZ, &ws);
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-        if (tcgetattr(STDIN_FILENO, &f->saved_stdin_attr) >= 0) {
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-                struct termios raw_stdin_attr;
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-
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-                f->saved_stdin = true;
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+        if (!read_only) {
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+                if (tcgetattr(STDIN_FILENO, &f->saved_stdin_attr) >= 0) {
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+                        struct termios raw_stdin_attr;
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-                raw_stdin_attr = f->saved_stdin_attr;
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-                cfmakeraw(&raw_stdin_attr);
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-                raw_stdin_attr.c_oflag = f->saved_stdin_attr.c_oflag;
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-                tcsetattr(STDIN_FILENO, TCSANOW, &raw_stdin_attr);
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-        }
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+                        f->saved_stdin = true;
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-        if (tcgetattr(STDOUT_FILENO, &f->saved_stdout_attr) >= 0) {
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-                struct termios raw_stdout_attr;
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+                        raw_stdin_attr = f->saved_stdin_attr;
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+                        cfmakeraw(&raw_stdin_attr);
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+                        raw_stdin_attr.c_oflag = f->saved_stdin_attr.c_oflag;
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+                        tcsetattr(STDIN_FILENO, TCSANOW, &raw_stdin_attr);
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+                }
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-                f->saved_stdout = true;
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+                if (tcgetattr(STDOUT_FILENO, &f->saved_stdout_attr) >= 0) {
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+                        struct termios raw_stdout_attr;
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-                raw_stdout_attr = f->saved_stdout_attr;
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-                cfmakeraw(&raw_stdout_attr);
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-                raw_stdout_attr.c_iflag = f->saved_stdout_attr.c_iflag;
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-                raw_stdout_attr.c_lflag = f->saved_stdout_attr.c_lflag;
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-                tcsetattr(STDOUT_FILENO, TCSANOW, &raw_stdout_attr);
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-        }
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+                        f->saved_stdout = true;
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-        r = sd_event_add_io(f->event, &f->master_event_source, master, EPOLLIN|EPOLLOUT|EPOLLET, on_master_event, f);
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-        if (r < 0)
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-                return r;
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+                        raw_stdout_attr = f->saved_stdout_attr;
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+                        cfmakeraw(&raw_stdout_attr);
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+                        raw_stdout_attr.c_iflag = f->saved_stdout_attr.c_iflag;
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+                        raw_stdout_attr.c_lflag = f->saved_stdout_attr.c_lflag;
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+                        tcsetattr(STDOUT_FILENO, TCSANOW, &raw_stdout_attr);
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+                }
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-        r = sd_event_add_io(f->event, &f->stdin_event_source, STDIN_FILENO, EPOLLIN|EPOLLET, on_stdin_event, f);
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-        if (r < 0 && r != -EPERM)
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-                return r;
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+                r = sd_event_add_io(f->event, &f->stdin_event_source, STDIN_FILENO, EPOLLIN|EPOLLET, on_stdin_event, f);
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+                if (r < 0 && r != -EPERM)
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+                        return r;
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+        }
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         r = sd_event_add_io(f->event, &f->stdout_event_source, STDOUT_FILENO, EPOLLOUT|EPOLLET, on_stdout_event, f);
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         if (r == -EPERM)
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@@ -372,6 +381,10 @@ int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward
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         else if (r < 0)
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                 return r;
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+        r = sd_event_add_io(f->event, &f->master_event_source, master, EPOLLIN|EPOLLOUT|EPOLLET, on_master_event, f);
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+        if (r < 0)
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+                return r;
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+
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         r = sd_event_add_signal(f->event, &f->sigwinch_event_source, SIGWINCH, on_sigwinch_event, f);
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         if (r < 0)
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                 return r;
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diff --git a/src/shared/ptyfwd.h b/src/shared/ptyfwd.h
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index d3e229bd7..6208a543d 100644
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--- a/src/shared/ptyfwd.h
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+++ b/src/shared/ptyfwd.h
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@@ -30,7 +30,7 @@
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 typedef struct PTYForward PTYForward;
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-int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward **f);
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+int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, bool read_only, PTYForward **f);
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 PTYForward *pty_forward_free(PTYForward *f);
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 int pty_forward_get_last_char(PTYForward *f, char *ch);