pty.c

Linux下伪终端的操作

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <signal.h>
#include <errno.h>

#include "pty_fork.c"
#include "fig18.20"

static void	set_noecho(int);
static void loop(int);

#define BUFFSIZE	1024

int main(int argc, char *argv[])
{
	int				fdm, c, interactive, noecho;
	pid_t			pid;
	char			slave_name[20];
	struct termios	orig_termios;
	struct winsize	size;
	char buf[BUFFSIZE];

	interactive = isatty(STDIN_FILENO);
	noecho = 0;

	opterr = 0;
	while ((c = getopt(argc, argv, "en")) != EOF) {
		switch (c) {
		case 'e':
			noecho = 1;
			break;

		case 'n':
			interactive = 0;
			break;

		case '?':
			fprintf(stderr, "unrecognized option: -%c\n", optopt);
			exit(1);
		}
	}
	//if (optind >= argc) {
	//	fprintf(stderr, "usage: pty [ -d driver -einv ] program [ arg ... ]\n");
	//	exit(1);
	//}

	if (interactive) {
		if (tcgetattr(STDIN_FILENO, &orig_termios) < 0) {
			fprintf(stderr, "tcgetattr error on stdin\n");
			exit(1);
		}
		if (ioctl(STDIN_FILENO, TIOCGWINSZ, (char *) &size) < 0) {
			fprintf(stderr, "TIOCGWINSZ error\n");
			exit(1);
		}
		pid = pty_fork(&fdm, slave_name, sizeof(slave_name), &orig_termios, &size);
	}
	else {
		pid = pty_fork(&fdm, slave_name, sizeof(slave_name), NULL, NULL);
	}

	if (pid < 0) {
		fprintf(stderr, "fork error\n");
		exit(1);
	}
	else if (pid == 0) {
		if (noecho)
			set_noecho(STDIN_FILENO);

		if (execvp(argv[optind], &argv[optind]) < 0) {
			fprintf(stderr, "can't execute: %s\n", argv[optind]);
			exit(1);
		}
	}

//	write(fdm, "hello\n", 6);
//	if (dup2(fdm, STDIN_FILENO) != STDIN_FILENO) {
//		fprintf(stderr, "dup2 error to stdin\n");
//		exit(1);
//	}
//	while ((c = fgetc(stdin)) != EOF) {
//		char cr = c;
//		write(1, &cr, 1);
//	}
//
	if (interactive) {
		//if (tty_raw(STDIN_FILENO) < 0) {
		if (tty_cbreak(STDIN_FILENO) < 0) {
			fprintf(stderr, "tty_raw error\n");
			exit(1);
		}
		if (atexit(tty_atexit) < 0) {
			fprintf(stderr, "atexit error\n");
			exit(1);
		}
	}

	loop(fdm);

	exit(0);
}

static void set_noecho(int fd)
{
	struct termios	stermios;

	if (tcgetattr(fd, &stermios) < 0) {
		fprintf(stderr, "tcgetattr error\n");
		exit(1);
	}

	stermios.c_lflag &= ~(ECHO | ECHOE | ECHOK | ECHONL);

	stermios.c_oflag &= ~(ONLCR);

	if (tcsetattr(fd, TCSANOW, &stermios) < 0) {
		fprintf(stderr, "tcsetattr error\n");
		exit(1);
	}
}

static volatile int	sigcaught;
typedef void Sigfunc(int);
static Sigfunc * signal_intr(int signo, Sigfunc *func);
static void sig_term(int signo);
static void loop(int ptym)
{
	pid_t	child;
	int		nread;
	char	buf[BUFFSIZE];

	if ((child = fork()) < 0) {
		fprintf(stderr, "fork error:%s\n", strerror(errno));
		exit(1);
	}
	else if (child == 0) {
		for ( ; ; ) {
			if ((nread = read(STDIN_FILENO, buf, BUFFSIZE)) < 0) {
				fprintf(stderr, "read error from stdin:%s\n", strerror(errno));
				exit(1);
			}
			else if (nread == 0)
				break;
			if (write(ptym, buf, nread) != nread) {
				fprintf(stderr, "writen error to master pty:%s\n", strerror(errno));
				exit(1);
			}
		}

		kill(getppid(), SIGTERM);
		exit(0);
	}

	if (signal_intr(SIGTERM, sig_term) == SIG_ERR) {
		fprintf(stderr, "signal_intr error for SIGTERM:%s\n", strerror(errno));
		exit(1);
	}

	for ( ; ; ) {
		if ((nread = read(ptym, buf, BUFFSIZE)) <= 0)
			break;
		if (write(STDOUT_FILENO, buf, nread) != nread) {
			fprintf(stderr, "writen error to stdout:%s\n", strerror(errno));
			exit(1);
		}
	}

	if (sigcaught == 0)
		kill(child, SIGTERM);
}

static Sigfunc * signal_intr(int signo, Sigfunc *func)
{
	struct sigaction	act, oact;

	act.sa_handler = func;
	sigemptyset(&act.sa_mask);
	act.sa_flags = 0;
	act.sa_flags |= SA_INTERRUPT;
	if (sigaction(signo, &act, &oact) < 0)
		return(SIG_ERR);
	return(oact.sa_handler);
}

static void sig_term(int signo)
{
	sigcaught = 1;
}