nspawn: when connected to pipes for stdin/stdout, pass them as-is to PID 1

Previously we always invoked the container PID 1 on /dev/console of the
container. With this change we do so only if nspawn was invoked
interactively (i.e. its stdin/stdout was connected to a TTY). In all other
cases we directly pass through the fds unmodified.

This has the benefit that nspawn can be added into shell pipelines.

https://bugs.freedesktop.org/show_bug.cgi?id=87732
This commit is contained in:
Lennart Poettering 2015-02-18 23:32:55 +01:00
parent 04155c6713
commit 9c857b9d16
5 changed files with 77 additions and 58 deletions

View File

@ -1150,7 +1150,7 @@ static int login_machine(int argc, char *argv[], void *userdata) {
sd_event_add_signal(event, NULL, SIGINT, NULL, NULL);
sd_event_add_signal(event, NULL, SIGTERM, NULL, NULL);
r = pty_forward_new(event, master, true, &forward);
r = pty_forward_new(event, master, true, false, &forward);
if (r < 0)
return log_error_errno(r, "Failed to create PTY forwarder: %m");

View File

@ -3606,6 +3606,7 @@ int main(int argc, char *argv[]) {
int ret = EXIT_SUCCESS;
union in_addr_union exposed = {};
_cleanup_release_lock_file_ LockFile tree_global_lock = LOCK_FILE_INIT, tree_local_lock = LOCK_FILE_INIT;
bool interactive;
log_parse_environment();
log_open();
@ -3779,6 +3780,8 @@ int main(int argc, char *argv[]) {
goto finish;
}
interactive = isatty(STDIN_FILENO) > 0 && isatty(STDOUT_FILENO) > 0;
master = posix_openpt(O_RDWR|O_NOCTTY|O_CLOEXEC|O_NDELAY);
if (master < 0) {
r = log_error_errno(errno, "Failed to acquire pseudo tty: %m");
@ -3791,15 +3794,15 @@ int main(int argc, char *argv[]) {
goto finish;
}
if (!arg_quiet)
log_info("Spawning container %s on %s.\nPress ^] three times within 1s to kill container.",
arg_machine, arg_image ?: arg_directory);
if (unlockpt(master) < 0) {
r = log_error_errno(errno, "Failed to unlock tty: %m");
goto finish;
}
if (!arg_quiet)
log_info("Spawning container %s on %s.\nPress ^] three times within 1s to kill container.",
arg_machine, arg_image ?: arg_directory);
assert_se(sigemptyset(&mask) == 0);
sigset_add_many(&mask, SIGCHLD, SIGWINCH, SIGTERM, SIGINT, -1);
assert_se(sigprocmask(SIG_BLOCK, &mask, NULL) == 0);
@ -3885,9 +3888,6 @@ int main(int argc, char *argv[]) {
master = safe_close(master);
close_nointr(STDIN_FILENO);
close_nointr(STDOUT_FILENO);
close_nointr(STDERR_FILENO);
kmsg_socket_pair[0] = safe_close(kmsg_socket_pair[0]);
rtnl_socket_pair[0] = safe_close(rtnl_socket_pair[0]);
@ -3895,21 +3895,27 @@ int main(int argc, char *argv[]) {
reset_all_signal_handlers();
reset_signal_mask();
r = open_terminal(console, O_RDWR);
if (r != STDIN_FILENO) {
if (r >= 0) {
safe_close(r);
r = -EINVAL;
if (interactive) {
close_nointr(STDIN_FILENO);
close_nointr(STDOUT_FILENO);
close_nointr(STDERR_FILENO);
r = open_terminal(console, O_RDWR);
if (r != STDIN_FILENO) {
if (r >= 0) {
safe_close(r);
r = -EINVAL;
}
log_error_errno(r, "Failed to open console: %m");
_exit(EXIT_FAILURE);
}
log_error_errno(r, "Failed to open console: %m");
_exit(EXIT_FAILURE);
}
if (dup2(STDIN_FILENO, STDOUT_FILENO) != STDOUT_FILENO ||
dup2(STDIN_FILENO, STDERR_FILENO) != STDERR_FILENO) {
log_error_errno(errno, "Failed to duplicate console: %m");
_exit(EXIT_FAILURE);
if (dup2(STDIN_FILENO, STDOUT_FILENO) != STDOUT_FILENO ||
dup2(STDIN_FILENO, STDERR_FILENO) != STDERR_FILENO) {
log_error_errno(errno, "Failed to duplicate console: %m");
_exit(EXIT_FAILURE);
}
}
if (setsid() < 0) {
@ -4252,7 +4258,7 @@ int main(int argc, char *argv[]) {
rtnl_socket_pair[0] = safe_close(rtnl_socket_pair[0]);
r = pty_forward_new(event, master, true, &forward);
r = pty_forward_new(event, master, true, !interactive, &forward);
if (r < 0) {
log_error_errno(r, "Failed to create PTY forwarder: %m");
goto finish;

View File

@ -776,7 +776,7 @@ static int start_transient_service(
if (!arg_quiet)
log_info("Running as unit %s.\nPress ^] three times within 1s to disconnect TTY.", service);
r = pty_forward_new(event, master, false, &forward);
r = pty_forward_new(event, master, false, false, &forward);
if (r < 0)
return log_error_errno(r, "Failed to create PTY forwarder: %m");

View File

@ -42,6 +42,8 @@ struct PTYForward {
struct termios saved_stdin_attr;
struct termios saved_stdout_attr;
bool read_only:1;
bool saved_stdin:1;
bool saved_stdout:1;
@ -298,7 +300,13 @@ static int on_sigwinch_event(sd_event_source *e, const struct signalfd_siginfo *
return 0;
}
int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward **ret) {
int pty_forward_new(
sd_event *event,
int master,
bool ignore_vhangup,
bool read_only,
PTYForward **ret) {
_cleanup_(pty_forward_freep) PTYForward *f = NULL;
struct winsize ws;
int r;
@ -307,6 +315,7 @@ int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward
if (!f)
return -ENOMEM;
f->read_only = read_only;
f->ignore_vhangup = ignore_vhangup;
if (event)
@ -317,13 +326,15 @@ int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward
return r;
}
r = fd_nonblock(STDIN_FILENO, true);
if (r < 0)
return r;
if (!read_only) {
r = fd_nonblock(STDIN_FILENO, true);
if (r < 0)
return r;
r = fd_nonblock(STDOUT_FILENO, true);
if (r < 0)
return r;
r = fd_nonblock(STDOUT_FILENO, true);
if (r < 0)
return r;
}
r = fd_nonblock(master, true);
if (r < 0)
@ -334,37 +345,35 @@ int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward
if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0)
(void)ioctl(master, TIOCSWINSZ, &ws);
if (tcgetattr(STDIN_FILENO, &f->saved_stdin_attr) >= 0) {
struct termios raw_stdin_attr;
if (!read_only) {
if (tcgetattr(STDIN_FILENO, &f->saved_stdin_attr) >= 0) {
struct termios raw_stdin_attr;
f->saved_stdin = true;
f->saved_stdin = true;
raw_stdin_attr = f->saved_stdin_attr;
cfmakeraw(&raw_stdin_attr);
raw_stdin_attr.c_oflag = f->saved_stdin_attr.c_oflag;
tcsetattr(STDIN_FILENO, TCSANOW, &raw_stdin_attr);
raw_stdin_attr = f->saved_stdin_attr;
cfmakeraw(&raw_stdin_attr);
raw_stdin_attr.c_oflag = f->saved_stdin_attr.c_oflag;
tcsetattr(STDIN_FILENO, TCSANOW, &raw_stdin_attr);
}
if (tcgetattr(STDOUT_FILENO, &f->saved_stdout_attr) >= 0) {
struct termios raw_stdout_attr;
f->saved_stdout = true;
raw_stdout_attr = f->saved_stdout_attr;
cfmakeraw(&raw_stdout_attr);
raw_stdout_attr.c_iflag = f->saved_stdout_attr.c_iflag;
raw_stdout_attr.c_lflag = f->saved_stdout_attr.c_lflag;
tcsetattr(STDOUT_FILENO, TCSANOW, &raw_stdout_attr);
}
r = sd_event_add_io(f->event, &f->stdin_event_source, STDIN_FILENO, EPOLLIN|EPOLLET, on_stdin_event, f);
if (r < 0 && r != -EPERM)
return r;
}
if (tcgetattr(STDOUT_FILENO, &f->saved_stdout_attr) >= 0) {
struct termios raw_stdout_attr;
f->saved_stdout = true;
raw_stdout_attr = f->saved_stdout_attr;
cfmakeraw(&raw_stdout_attr);
raw_stdout_attr.c_iflag = f->saved_stdout_attr.c_iflag;
raw_stdout_attr.c_lflag = f->saved_stdout_attr.c_lflag;
tcsetattr(STDOUT_FILENO, TCSANOW, &raw_stdout_attr);
}
r = sd_event_add_io(f->event, &f->master_event_source, master, EPOLLIN|EPOLLOUT|EPOLLET, on_master_event, f);
if (r < 0)
return r;
r = sd_event_add_io(f->event, &f->stdin_event_source, STDIN_FILENO, EPOLLIN|EPOLLET, on_stdin_event, f);
if (r < 0 && r != -EPERM)
return r;
r = sd_event_add_io(f->event, &f->stdout_event_source, STDOUT_FILENO, EPOLLOUT|EPOLLET, on_stdout_event, f);
if (r == -EPERM)
/* stdout without epoll support. Likely redirected to regular file. */
@ -372,6 +381,10 @@ int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward
else if (r < 0)
return r;
r = sd_event_add_io(f->event, &f->master_event_source, master, EPOLLIN|EPOLLOUT|EPOLLET, on_master_event, f);
if (r < 0)
return r;
r = sd_event_add_signal(f->event, &f->sigwinch_event_source, SIGWINCH, on_sigwinch_event, f);
if (r < 0)
return r;

View File

@ -30,7 +30,7 @@
typedef struct PTYForward PTYForward;
int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, PTYForward **f);
int pty_forward_new(sd_event *event, int master, bool ignore_vhangup, bool read_only, PTYForward **f);
PTYForward *pty_forward_free(PTYForward *f);
int pty_forward_get_last_char(PTYForward *f, char *ch);