1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
4 */
5
6#include <stdio.h>
7#include <stdlib.h>
8#include <string.h>
9#include <errno.h>
10#include <termios.h>
11#include <unistd.h>
12#include <netinet/in.h>
13#include "chan_user.h"
14#include <os.h>
15#include "port.h"
16#include <um_malloc.h>
17
18struct port_chan {
19	int raw;
20	struct termios tt;
21	void *kernel_data;
22	char dev[sizeof("32768\0")];
23};
24
25static void *port_init(char *str, int device, const struct chan_opts *opts)
26{
27	struct port_chan *data;
28	void *kern_data;
29	char *end;
30	int port;
31
32	if (*str != ':') {
33		printk(UM_KERN_ERR "port_init : channel type 'port' must "
34		       "specify a port number\n");
35		return NULL;
36	}
37	str++;
38	port = strtoul(str, &end, 0);
39	if ((*end != '\0') || (end == str)) {
40		printk(UM_KERN_ERR "port_init : couldn't parse port '%s'\n",
41		       str);
42		return NULL;
43	}
44
45	kern_data = port_data(port);
46	if (kern_data == NULL)
47		return NULL;
48
49	data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
50	if (data == NULL)
51		goto err;
52
53	*data = ((struct port_chan) { .raw  		= opts->raw,
54				      .kernel_data 	= kern_data });
55	sprintf(data->dev, "%d", port);
56
57	return data;
58 err:
59	port_kern_free(kern_data);
60	return NULL;
61}
62
63static void port_free(void *d)
64{
65	struct port_chan *data = d;
66
67	port_kern_free(data->kernel_data);
68	kfree(data);
69}
70
71static int port_open(int input, int output, int primary, void *d,
72		     char **dev_out)
73{
74	struct port_chan *data = d;
75	int fd, err;
76
77	fd = port_wait(data->kernel_data);
78	if ((fd >= 0) && data->raw) {
79		CATCH_EINTR(err = tcgetattr(fd, &data->tt));
80		if (err)
81			return err;
82
83		err = raw(fd);
84		if (err)
85			return err;
86	}
87	*dev_out = data->dev;
88	return fd;
89}
90
91static void port_close(int fd, void *d)
92{
93	struct port_chan *data = d;
94
95	port_remove_dev(data->kernel_data);
96	os_close_file(fd);
97}
98
99const struct chan_ops port_ops = {
100	.type		= "port",
101	.init		= port_init,
102	.open		= port_open,
103	.close		= port_close,
104	.read	        = generic_read,
105	.write		= generic_write,
106	.console_write	= generic_console_write,
107	.window_size	= generic_window_size,
108	.free		= port_free,
109	.winch		= 1,
110};
111
112int port_listen_fd(int port)
113{
114	struct sockaddr_in addr;
115	int fd, err, arg;
116
117	fd = socket(PF_INET, SOCK_STREAM, 0);
118	if (fd == -1)
119		return -errno;
120
121	arg = 1;
122	if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &arg, sizeof(arg)) < 0) {
123		err = -errno;
124		goto out;
125	}
126
127	addr.sin_family = AF_INET;
128	addr.sin_port = htons(port);
129	addr.sin_addr.s_addr = htonl(INADDR_ANY);
130	if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
131		err = -errno;
132		goto out;
133	}
134
135	if (listen(fd, 1) < 0) {
136		err = -errno;
137		goto out;
138	}
139
140	err = os_set_fd_block(fd, 0);
141	if (err < 0)
142		goto out;
143
144	return fd;
145 out:
146	close(fd);
147	return err;
148}
149
150struct port_pre_exec_data {
151	int sock_fd;
152	int pipe_fd;
153};
154
155static void port_pre_exec(void *arg)
156{
157	struct port_pre_exec_data *data = arg;
158
159	dup2(data->sock_fd, 0);
160	dup2(data->sock_fd, 1);
161	dup2(data->sock_fd, 2);
162	close(data->sock_fd);
163	dup2(data->pipe_fd, 3);
164	shutdown(3, SHUT_RD);
165	close(data->pipe_fd);
166}
167
168int port_connection(int fd, int *socket, int *pid_out)
169{
170	int new, err;
171	char *env;
172	char *argv[] = { "in.telnetd", "-L",
173			 OS_LIB_PATH "/uml/port-helper", NULL };
174	struct port_pre_exec_data data;
175
176	if ((env = getenv("UML_PORT_HELPER")))
177		argv[2] = env;
178
179	new = accept(fd, NULL, 0);
180	if (new < 0)
181		return -errno;
182
183	err = os_access(argv[2], X_OK);
184	if (err < 0) {
185		printk(UM_KERN_ERR "port_connection : error accessing port-helper "
186		       "executable at %s: %s\n", argv[2], strerror(-err));
187		if (env == NULL)
188			printk(UM_KERN_ERR "Set UML_PORT_HELPER environment "
189				"variable to path to uml-utilities port-helper "
190				"binary\n");
191		goto out_close;
192	}
193
194	err = os_pipe(socket, 0, 0);
195	if (err < 0)
196		goto out_close;
197
198	data = ((struct port_pre_exec_data)
199		{ .sock_fd  		= new,
200		  .pipe_fd 		= socket[1] });
201
202	err = run_helper(port_pre_exec, &data, argv);
203	if (err < 0)
204		goto out_shutdown;
205
206	*pid_out = err;
207	return new;
208
209 out_shutdown:
210	shutdown(socket[0], SHUT_RDWR);
211	close(socket[0]);
212	shutdown(socket[1], SHUT_RDWR);
213	close(socket[1]);
214 out_close:
215	close(new);
216	return err;
217}
218