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Diffstat (limited to '')
| -rw-r--r-- | bin/ptee.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/bin/ptee.c b/bin/ptee.c new file mode 100644 index 00000000..52350a21 --- /dev/null +++ b/bin/ptee.c @@ -0,0 +1,151 @@ +/* Copyright (C) 2019 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 <errno.h> +#include <poll.h> +#include <signal.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/ioctl.h> +#include <sys/time.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); +} + +static void handler(int sig) { + (void)sig; +} + +int main(int argc, char *argv[]) { + int timer = 0; + for (int opt; 0 < (opt = getopt(argc, argv, "t:"));) { + switch (opt) { + break; case 't': timer = atoi(optarg); + break; default: return EX_USAGE; + } + } + argc -= optind; + argv += optind; + + if (argc < 1) 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[0], argv); + err(EX_NOINPUT, "%s", argv[0]); + } + + if (timer) { + signal(SIGALRM, handler); + struct timeval tv = { + .tv_sec = timer / 1000, + .tv_usec = timer % 1000 * 1000, + }; + struct itimerval itv = { tv, tv }; + setitimer(ITIMER_REAL, &itv, NULL); + } + + char mc[] = "\x1B[10i"; + bool stop = false; + + byte buf[4096]; + struct pollfd fds[2] = { + { .events = POLLIN, .fd = STDIN_FILENO }, + { .events = POLLIN, .fd = pty }, + }; + for (;;) { + int nfds = poll(fds, 2, -1); + if (nfds < 0 && errno != EINTR) err(EX_IOERR, "poll"); + + if (nfds < 0) { + ssize_t wlen = write(STDOUT_FILENO, mc, sizeof(mc) - 1); + if (wlen < 0) err(EX_IOERR, "write"); + continue; + } + + 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('Q')) { + stop ^= true; + continue; + } + + if (rlen == 1 && buf[0] == CTRL('S')) { + ssize_t wlen = write(STDOUT_FILENO, mc, sizeof(mc) - 1); + if (wlen < 0) err(EX_IOERR, "write"); + 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; + } +} |