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/* Copyright (C) 2018  June 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 <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 uint;
typedef unsigned char byte;

static const uint BaudRate = 19200;

static struct termios saveTerm;
static void restoreTerm(void) {
	tcsetattr(STDIN_FILENO, TCSADRAIN, &saveTerm);
}

int main(int argc, char *argv[]) {
	int error;

	if (argc < 2) return EX_USAGE;

	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, "TIOCGWINSZ");

	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]);
	}

	byte c;
	struct pollfd fds[2] = {
		{ .events = POLLIN, .fd = STDIN_FILENO },
		{ .events = POLLIN, .fd = pty },
	};
	while (usleep(8 * 1000000 / BaudRate), 0 < poll(fds, 2, -1)) {
		if (fds[0].revents) {
			ssize_t size = read(STDIN_FILENO, &c, 1);
			if (size < 0) err(EX_IOERR, "read(%d)", STDIN_FILENO);
			size = write(pty, &c, 1);
			if (size < 0) err(EX_IOERR, "write(%d)", pty);
		}

		if (fds[1].revents) {
			ssize_t size = read(pty, &c, 1);
			if (size < 0) err(EX_IOERR, "read(%d)", pty);
			size = write(STDOUT_FILENO, &c, 1);
			if (size < 0) err(EX_IOERR, "write(%d)", STDOUT_FILENO);
		}

		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");
}
really enjoyed it. Read it faster than the first one too, despite its length. 2022-06-25Bump xterm font size to 12June McEnroe 2022-06-10Handle subshells (and functions) inside substitutionsJune McEnroe 2022-06-10Switch to jorts Install scriptJune McEnroe 2022-06-08Indicate if still reading or no resultsJune McEnroe 2022-06-08Add Maiden, Mother, CroneJune McEnroe Mixed bag like most collections of short stories. Some of them are pretty good. The author of the worst written story also has the worst written bio. 2022-06-05FIRST SHOW IN 2.5 YEARS BABEY!!!June McEnroe 2022-06-03Set line number on File linesJune McEnroe 2022-06-03Stop polling stdin after EOFJune McEnroe 2022-06-02Set TABSIZE=4June McEnroe Absolutely indiscriminately. 2022-06-02Do basic match highlightingJune McEnroe 2022-06-02Clean up parsing a littleJune McEnroe 2022-06-02Don't duplicate path stringJune McEnroe 2022-06-02Use stderr instead of /dev/tty, realloc buffer if lines too longJune McEnroe For some reason I haven't been able to figure out, trying to poll /dev/tty returns POLLNVAL (and this was using 100% CPU looping), but using stderr instead works fine. 2022-06-02Add initial working version of qfJune McEnroe 2022-05-29Set prompt for okshJune McEnroe