xref: /linux/arch/um/drivers/port_user.c (revision 4f2c0a4acffbec01079c28f839422e64ddeff004)
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 
18 struct port_chan {
19 	int raw;
20 	struct termios tt;
21 	void *kernel_data;
22 	char dev[sizeof("32768\0")];
23 };
24 
port_init(char * str,int device,const struct chan_opts * opts)25 static 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 
port_free(void * d)63 static 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 
port_open(int input,int output,int primary,void * d,char ** dev_out)71 static 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 
port_close(int fd,void * d)91 static 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 
99 const 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 
port_listen_fd(int port)112 int 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 
150 struct port_pre_exec_data {
151 	int sock_fd;
152 	int pipe_fd;
153 };
154 
port_pre_exec(void * arg)155 static 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 
port_connection(int fd,int * socket,int * pid_out)168 int 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