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/*-*- 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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