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/* Copyright (C) 2019 C. McEnroe <june@causal.agency>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <err.h>
#include <poll.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/wait.h>
#include <sysexits.h>
#include <termios.h>
#include <unistd.h>
#if defined __FreeBSD__
#include <libutil.h>
#elif defined __linux__
#include <pty.h>
#else
#include <util.h>
#endif
typedef unsigned char byte;
static struct termios saveTerm;
static void restoreTerm(void) {
tcsetattr(STDIN_FILENO, TCSADRAIN, &saveTerm);
}
int main(int argc, char *argv[]) {
if (argc < 2) return EX_USAGE;
if (isatty(STDOUT_FILENO)) errx(EX_USAGE, "stdout is not redirected");
int error = tcgetattr(STDIN_FILENO, &saveTerm);
if (error) err(EX_IOERR, "tcgetattr");
atexit(restoreTerm);
struct termios raw = saveTerm;
cfmakeraw(&raw);
error = tcsetattr(STDIN_FILENO, TCSADRAIN, &raw);
if (error) err(EX_IOERR, "tcsetattr");
struct winsize window;
error = ioctl(STDIN_FILENO, TIOCGWINSZ, &window);
if (error) err(EX_IOERR, "ioctl");
int pty;
pid_t pid = forkpty(&pty, NULL, NULL, &window);
if (pid < 0) err(EX_OSERR, "forkpty");
if (!pid) {
execvp(argv[1], &argv[1]);
err(EX_NOINPUT, "%s", argv[1]);
}
bool stop = false;
byte buf[4096];
struct pollfd fds[2] = {
{ .events = POLLIN, .fd = STDIN_FILENO },
{ .events = POLLIN, .fd = pty },
};
while (0 < poll(fds, 2, -1)) {
if (fds[0].revents & POLLIN) {
ssize_t rlen = read(STDIN_FILENO, buf, sizeof(buf));
if (rlen < 0) err(EX_IOERR, "read");
if (rlen == 1 && buf[0] == CTRL('S')) {
stop ^= true;
continue;
}
ssize_t wlen = write(pty, buf, rlen);
if (wlen < 0) err(EX_IOERR, "write");
}
if (fds[1].revents & POLLIN) {
ssize_t rlen = read(pty, buf, sizeof(buf));
if (rlen < 0) err(EX_IOERR, "read");
ssize_t wlen = write(STDIN_FILENO, buf, rlen);
if (wlen < 0) err(EX_IOERR, "write");
if (!stop) {
wlen = write(STDOUT_FILENO, buf, rlen);
if (wlen < 0) err(EX_IOERR, "write");
}
}
int status;
pid_t dead = waitpid(pid, &status, WNOHANG);
if (dead < 0) err(EX_OSERR, "waitpid");
if (dead) return WIFEXITED(status) ? WEXITSTATUS(status) : EX_SOFTWARE;
}
err(EX_IOERR, "poll");
}
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