pty-test.c

/*	Copyright 2015-2022 Rivoreo

	Permission is hereby granted, free of charge, to any person obtaining
	a copy of this software and associated documentation files (the
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	without limitation the rights to use, copy, modify, merge, publish,
	distribute, sublicense, and/or sell copies of the Software, and to
	permit persons to whom the Software is furnished to do so, subject to
	the following conditions:

	The above copyright notice and this permission notice shall be
	included in all copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
	NONINFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE
	FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
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	WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#define _ALL_SOURCE
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#ifdef __SVR4
#include <sys/stropts.h>
#endif
#include <limits.h>
#ifdef HAVE_OPENPTY
#if defined __GLIBC__ || defined __CYGWIN__ || defined __INTERIX
#include <pty.h>
#elif defined __APPLE__ && defined __MACH__
#include <util.h>
#else
#include <libutil.h>
#endif
#endif

#ifndef __INTERIX
#define HAVE_POSIX_OPENPT
#endif

#define BSD_PTY_NAME_1 "pqrstuvwxyzabcdePQRSTUVWXYZABCDE"
#define BSD_PTY_NAME_2 "0123456789abcdefghijklmnopqrstuv"

static int open_slave_from_master(int master_fd) {
	if(grantpt(master_fd) == -1) {
		perror("grantpt");
		return -1;
	}
	if(unlockpt(master_fd) == -1) {
		perror("unlockpt");
		return -1;
	}
	char *name = ptsname(master_fd);
	if(!name) {
		perror("ptsname");
		return -1;
	}
	printf("Slave device name: \"%s\"\n", name);
	int fd = open(name, O_RDWR | O_NOCTTY);
	if(fd == -1) {
		perror(name);
		return -1;
	}
#ifdef I_PUSH
	ioctl(fd, I_PUSH, "ptem");
	ioctl(fd, I_PUSH, "ldterm");
#endif
	return fd;
}

int main(int argc, char **argv) {
	int master_fd, slave_fd;
	if(argc != 2) {
		fprintf(stderr, "Usage: %s {"
#ifdef HAVE_POSIX_OPENPT
			" posix | posix_openpt |"
#endif
			" sysv | unix98 | ptmx | bsd | bsd_pty"
#ifdef HAVE_OPENPTY
			" | openpty"
#endif
			" }\n", argv[0]);
		return -1;
	}
#ifdef HAVE_POSIX_OPENPT
	if(strcmp(argv[1], "posix") == 0 || strcmp(argv[1], "posix_openpt") == 0) {
		master_fd = posix_openpt(O_RDWR | O_NOCTTY);
		if(master_fd == -1) {
			perror("posix_openpt");
			return 1;
		}
		slave_fd = open_slave_from_master(master_fd);
		if(slave_fd == -1) return 1;
	} else
#endif
	if(strcmp(argv[1], "sysv") == 0 || strcmp(argv[1], "unix98") == 0 || strcmp(argv[1], "ptmx") == 0) {
		master_fd = open("/dev/ptmx", O_RDWR);
		if(master_fd == -1) {
			perror("open: /dev/ptmx");
			return 1;
		}
		slave_fd = open_slave_from_master(master_fd);
		if(slave_fd == -1) return 1;
	} else if(strcmp(argv[1], "bsd") == 0 || strcmp(argv[1], "bsd_pty") == 0) {
		unsigned int i, j;
		char path[11] = "/dev/pty";
		path[10] = 0;
		for(i = 0; i < sizeof BSD_PTY_NAME_1 - 1; i++) {
			for(j = 0; j < sizeof BSD_PTY_NAME_2 - 1; j++) {
				path[8] = BSD_PTY_NAME_1[i];
				path[9] = BSD_PTY_NAME_2[j];
				master_fd = open(path, O_RDWR);
				if(master_fd == -1) {
					perror(path);
					continue;
				}
				path[5] = 't';
				printf("Slave device name: \"%s\"\n", path);
				slave_fd = open(path, O_RDWR);
				if(slave_fd == -1) {
					perror(path);
					return 1;
				}
				goto allocated;
			}
		}
		fputs("Cannot find a free master device\n", stderr);
		return 1;
#ifdef HAVE_OPENPTY
	} else if(strcmp(argv[1], "openpty") == 0) {
		char path[PATH_MAX];
		if(openpty(&master_fd, &slave_fd, path, NULL, NULL) < 0) {
			perror("openpty");
			return 1;
		}
		printf("Slave device name: \"%s\"\n", path);
#endif
	} else {
		fprintf(stderr, "%s: API type %s not recognized\n", argv[0], argv[1]);
		return -1;
	}
allocated:
	printf("master_fd = %d, slave_fd = %d\n", master_fd, slave_fd);
	printf("isatty(%d) = %d, isatty(%d) = %d\n", master_fd, isatty(master_fd), slave_fd, isatty(slave_fd));
	const char *name = ttyname(master_fd);
	printf("ttyname(%d) = %p<%s>, ", master_fd, name, name);
	name = ttyname(slave_fd);
	printf("ttyname(%d) = %p<%s>\n", slave_fd, name, name);
	return 0;
}