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-rw-r--r--src/shared/ptyfwd.c252
1 files changed, 252 insertions, 0 deletions
diff --git a/src/shared/ptyfwd.c b/src/shared/ptyfwd.c
new file mode 100644
index 0000000000..1e2852b1af
--- /dev/null
+++ b/src/shared/ptyfwd.c
@@ -0,0 +1,252 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2010-2013 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/epoll.h>
+#include <sys/signalfd.h>
+#include <sys/ioctl.h>
+#include <limits.h>
+#include <termios.h>
+
+#include "util.h"
+#include "ptyfwd.h"
+
+int process_pty(int master, sigset_t *mask, pid_t kill_pid, int signo) {
+ char in_buffer[LINE_MAX], out_buffer[LINE_MAX];
+ size_t in_buffer_full = 0, out_buffer_full = 0;
+ struct epoll_event stdin_ev, stdout_ev, master_ev, signal_ev;
+ bool stdin_readable = false, stdout_writable = false, master_readable = false, master_writable = false;
+ bool tried_orderly_shutdown = false;
+ _cleanup_close_ int ep = -1, signal_fd = -1;
+
+ assert(master >= 0);
+ assert(mask);
+ assert(kill_pid == 0 || kill_pid > 1);
+ assert(signo >= 0 && signo < _NSIG);
+
+ fd_nonblock(STDIN_FILENO, 1);
+ fd_nonblock(STDOUT_FILENO, 1);
+ fd_nonblock(master, 1);
+
+ signal_fd = signalfd(-1, mask, SFD_NONBLOCK|SFD_CLOEXEC);
+ if (signal_fd < 0) {
+ log_error("signalfd(): %m");
+ return -errno;
+ }
+
+ ep = epoll_create1(EPOLL_CLOEXEC);
+ if (ep < 0) {
+ log_error("Failed to create epoll: %m");
+ return -errno;
+ }
+
+ /* We read from STDIN only if this is actually a TTY,
+ * otherwise we assume non-interactivity. */
+ if (isatty(STDIN_FILENO)) {
+ zero(stdin_ev);
+ stdin_ev.events = EPOLLIN|EPOLLET;
+ stdin_ev.data.fd = STDIN_FILENO;
+
+ if (epoll_ctl(ep, EPOLL_CTL_ADD, STDIN_FILENO, &stdin_ev) < 0) {
+ log_error("Failed to register STDIN in epoll: %m");
+ return -errno;
+ }
+ }
+
+ zero(stdout_ev);
+ stdout_ev.events = EPOLLOUT|EPOLLET;
+ stdout_ev.data.fd = STDOUT_FILENO;
+
+ zero(master_ev);
+ master_ev.events = EPOLLIN|EPOLLOUT|EPOLLET;
+ master_ev.data.fd = master;
+
+ zero(signal_ev);
+ signal_ev.events = EPOLLIN;
+ signal_ev.data.fd = signal_fd;
+
+ if (epoll_ctl(ep, EPOLL_CTL_ADD, STDOUT_FILENO, &stdout_ev) < 0) {
+ if (errno != EPERM) {
+ log_error("Failed to register stdout in epoll: %m");
+ return -errno;
+ }
+
+ /* stdout without epoll support. Likely redirected to regular file. */
+ stdout_writable = true;
+ }
+
+ if (epoll_ctl(ep, EPOLL_CTL_ADD, master, &master_ev) < 0 ||
+ epoll_ctl(ep, EPOLL_CTL_ADD, signal_fd, &signal_ev) < 0) {
+ log_error("Failed to register fds in epoll: %m");
+ return -errno;
+ }
+
+ for (;;) {
+ struct epoll_event ev[16];
+ ssize_t k;
+ int i, nfds;
+
+ nfds = epoll_wait(ep, ev, ELEMENTSOF(ev), -1);
+ if (nfds < 0) {
+
+ if (errno == EINTR || errno == EAGAIN)
+ continue;
+
+ log_error("epoll_wait(): %m");
+ return -errno;
+ }
+
+ assert(nfds >= 1);
+
+ for (i = 0; i < nfds; i++) {
+ if (ev[i].data.fd == STDIN_FILENO) {
+
+ if (ev[i].events & (EPOLLIN|EPOLLHUP))
+ stdin_readable = true;
+
+ } else if (ev[i].data.fd == STDOUT_FILENO) {
+
+ if (ev[i].events & (EPOLLOUT|EPOLLHUP))
+ stdout_writable = true;
+
+ } else if (ev[i].data.fd == master) {
+
+ if (ev[i].events & (EPOLLIN|EPOLLHUP))
+ master_readable = true;
+
+ if (ev[i].events & (EPOLLOUT|EPOLLHUP))
+ master_writable = true;
+
+ } else if (ev[i].data.fd == signal_fd) {
+ struct signalfd_siginfo sfsi;
+ ssize_t n;
+
+ n = read(signal_fd, &sfsi, sizeof(sfsi));
+ if (n != sizeof(sfsi)) {
+
+ if (n >= 0) {
+ log_error("Failed to read from signalfd: invalid block size");
+ return -EIO;
+ }
+
+ if (errno != EINTR && errno != EAGAIN) {
+ log_error("Failed to read from signalfd: %m");
+ return -errno;
+ }
+ } else {
+
+ if (sfsi.ssi_signo == SIGWINCH) {
+ struct winsize ws;
+
+ /* The window size changed, let's forward that. */
+ if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) >= 0)
+ ioctl(master, TIOCSWINSZ, &ws);
+
+ } else if (sfsi.ssi_signo == SIGTERM && kill_pid > 0 && signo > 0 && !tried_orderly_shutdown) {
+
+ if (kill(kill_pid, signo) < 0)
+ return 0;
+
+ log_info("Trying to halt container. Send SIGTERM again to trigger immediate termination.");
+
+ /* This only works for systemd... */
+ tried_orderly_shutdown = true;
+
+ } else
+ return 0;
+ }
+ }
+ }
+
+ while ((stdin_readable && in_buffer_full <= 0) ||
+ (master_writable && in_buffer_full > 0) ||
+ (master_readable && out_buffer_full <= 0) ||
+ (stdout_writable && out_buffer_full > 0)) {
+
+ if (stdin_readable && in_buffer_full < LINE_MAX) {
+
+ k = read(STDIN_FILENO, in_buffer + in_buffer_full, LINE_MAX - in_buffer_full);
+ if (k < 0) {
+
+ if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO)
+ stdin_readable = false;
+ else {
+ log_error("read(): %m");
+ return -errno;
+ }
+ } else
+ in_buffer_full += (size_t) k;
+ }
+
+ if (master_writable && in_buffer_full > 0) {
+
+ k = write(master, in_buffer, in_buffer_full);
+ if (k < 0) {
+
+ if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO)
+ master_writable = false;
+ else {
+ log_error("write(): %m");
+ return -errno;
+ }
+
+ } else {
+ assert(in_buffer_full >= (size_t) k);
+ memmove(in_buffer, in_buffer + k, in_buffer_full - k);
+ in_buffer_full -= k;
+ }
+ }
+
+ if (master_readable && out_buffer_full < LINE_MAX) {
+
+ k = read(master, out_buffer + out_buffer_full, LINE_MAX - out_buffer_full);
+ if (k < 0) {
+
+ if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO)
+ master_readable = false;
+ else {
+ log_error("read(): %m");
+ return -errno;
+ }
+ } else
+ out_buffer_full += (size_t) k;
+ }
+
+ if (stdout_writable && out_buffer_full > 0) {
+
+ k = write(STDOUT_FILENO, out_buffer, out_buffer_full);
+ if (k < 0) {
+
+ if (errno == EAGAIN || errno == EPIPE || errno == ECONNRESET || errno == EIO)
+ stdout_writable = false;
+ else {
+ log_error("write(): %m");
+ return -errno;
+ }
+
+ } else {
+ assert(out_buffer_full >= (size_t) k);
+ memmove(out_buffer, out_buffer + k, out_buffer_full - k);
+ out_buffer_full -= k;
+ }
+ }
+ }
+ }
+}
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