xref: /linux/arch/um/drivers/xterm.c (revision e80a48bade619ec5a92230b3d4ae84bfc2746822)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4  */
5 
6 #include <stddef.h>
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <unistd.h>
10 #include <errno.h>
11 #include <string.h>
12 #include <termios.h>
13 #include "chan_user.h"
14 #include <os.h>
15 #include <um_malloc.h>
16 #include "xterm.h"
17 
18 struct xterm_chan {
19 	int pid;
20 	int helper_pid;
21 	int chan_fd;
22 	char *title;
23 	int device;
24 	int raw;
25 	struct termios tt;
26 };
27 
28 static void *xterm_init(char *str, int device, const struct chan_opts *opts)
29 {
30 	struct xterm_chan *data;
31 
32 	data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
33 	if (data == NULL)
34 		return NULL;
35 	*data = ((struct xterm_chan) { .pid 		= -1,
36 				       .helper_pid 	= -1,
37 				       .chan_fd		= -1,
38 				       .device 		= device,
39 				       .title 		= opts->xterm_title,
40 				       .raw  		= opts->raw } );
41 	return data;
42 }
43 
44 /* Only changed by xterm_setup, which is a setup */
45 static char *terminal_emulator = CONFIG_XTERM_CHAN_DEFAULT_EMULATOR;
46 static char *title_switch = "-T";
47 static char *exec_switch = "-e";
48 
49 static int __init xterm_setup(char *line, int *add)
50 {
51 	*add = 0;
52 	terminal_emulator = line;
53 
54 	line = strchr(line, ',');
55 	if (line == NULL)
56 		return 0;
57 
58 	*line++ = '\0';
59 	if (*line)
60 		title_switch = line;
61 
62 	line = strchr(line, ',');
63 	if (line == NULL)
64 		return 0;
65 
66 	*line++ = '\0';
67 	if (*line)
68 		exec_switch = line;
69 
70 	return 0;
71 }
72 
73 __uml_setup("xterm=", xterm_setup,
74 "xterm=<terminal emulator>,<title switch>,<exec switch>\n"
75 "    Specifies an alternate terminal emulator to use for the debugger,\n"
76 "    consoles, and serial lines when they are attached to the xterm channel.\n"
77 "    The values are the terminal emulator binary, the switch it uses to set\n"
78 "    its title, and the switch it uses to execute a subprocess,\n"
79 "    respectively.  The title switch must have the form '<switch> title',\n"
80 "    not '<switch>=title'.  Similarly, the exec switch must have the form\n"
81 "    '<switch> command arg1 arg2 ...'.\n"
82 "    The default values are 'xterm=" CONFIG_XTERM_CHAN_DEFAULT_EMULATOR
83      ",-T,-e'.\n"
84 "    Values for gnome-terminal are 'xterm=gnome-terminal,-t,-x'.\n\n"
85 );
86 
87 static int xterm_open(int input, int output, int primary, void *d,
88 		      char **dev_out)
89 {
90 	struct xterm_chan *data = d;
91 	int pid, fd, new, err;
92 	char title[256], file[] = "/tmp/xterm-pipeXXXXXX";
93 	char *argv[] = { terminal_emulator, title_switch, title, exec_switch,
94 			 OS_LIB_PATH "/uml/port-helper", "-uml-socket",
95 			 file, NULL };
96 
97 	if (access(argv[4], X_OK) < 0)
98 		argv[4] = "port-helper";
99 
100 	/*
101 	 * Check that DISPLAY is set, this doesn't guarantee the xterm
102 	 * will work but w/o it we can be pretty sure it won't.
103 	 */
104 	if (getenv("DISPLAY") == NULL) {
105 		printk(UM_KERN_ERR "xterm_open: $DISPLAY not set.\n");
106 		return -ENODEV;
107 	}
108 
109 	/*
110 	 * This business of getting a descriptor to a temp file,
111 	 * deleting the file and closing the descriptor is just to get
112 	 * a known-unused name for the Unix socket that we really
113 	 * want.
114 	 */
115 	fd = mkstemp(file);
116 	if (fd < 0) {
117 		err = -errno;
118 		printk(UM_KERN_ERR "xterm_open : mkstemp failed, errno = %d\n",
119 		       errno);
120 		return err;
121 	}
122 
123 	if (unlink(file)) {
124 		err = -errno;
125 		printk(UM_KERN_ERR "xterm_open : unlink failed, errno = %d\n",
126 		       errno);
127 		close(fd);
128 		return err;
129 	}
130 	close(fd);
131 
132 	fd = os_create_unix_socket(file, sizeof(file), 1);
133 	if (fd < 0) {
134 		printk(UM_KERN_ERR "xterm_open : create_unix_socket failed, "
135 		       "errno = %d\n", -fd);
136 		return fd;
137 	}
138 
139 	sprintf(title, data->title, data->device);
140 	pid = run_helper(NULL, NULL, argv);
141 	if (pid < 0) {
142 		err = pid;
143 		printk(UM_KERN_ERR "xterm_open : run_helper failed, "
144 		       "errno = %d\n", -err);
145 		goto out_close1;
146 	}
147 
148 	err = os_set_fd_block(fd, 0);
149 	if (err < 0) {
150 		printk(UM_KERN_ERR "xterm_open : failed to set descriptor "
151 		       "non-blocking, err = %d\n", -err);
152 		goto out_kill;
153 	}
154 
155 	data->chan_fd = fd;
156 	new = xterm_fd(fd, &data->helper_pid);
157 	if (new < 0) {
158 		err = new;
159 		printk(UM_KERN_ERR "xterm_open : os_rcv_fd failed, err = %d\n",
160 		       -err);
161 		goto out_kill;
162 	}
163 
164 	err = os_set_fd_block(new, 0);
165 	if (err) {
166 		printk(UM_KERN_ERR "xterm_open : failed to set xterm "
167 		       "descriptor non-blocking, err = %d\n", -err);
168 		goto out_close2;
169 	}
170 
171 	CATCH_EINTR(err = tcgetattr(new, &data->tt));
172 	if (err) {
173 		new = err;
174 		goto out_close2;
175 	}
176 
177 	if (data->raw) {
178 		err = raw(new);
179 		if (err) {
180 			new = err;
181 			goto out_close2;
182 		}
183 	}
184 
185 	unlink(file);
186 	data->pid = pid;
187 	*dev_out = NULL;
188 
189 	return new;
190 
191  out_close2:
192 	close(new);
193  out_kill:
194 	os_kill_process(pid, 1);
195  out_close1:
196 	close(fd);
197 
198 	return err;
199 }
200 
201 static void xterm_close(int fd, void *d)
202 {
203 	struct xterm_chan *data = d;
204 
205 	if (data->pid != -1)
206 		os_kill_process(data->pid, 1);
207 	data->pid = -1;
208 
209 	if (data->helper_pid != -1)
210 		os_kill_process(data->helper_pid, 0);
211 	data->helper_pid = -1;
212 
213 	if (data->chan_fd != -1)
214 		os_close_file(data->chan_fd);
215 	os_close_file(fd);
216 }
217 
218 const struct chan_ops xterm_ops = {
219 	.type		= "xterm",
220 	.init		= xterm_init,
221 	.open		= xterm_open,
222 	.close		= xterm_close,
223 	.read		= generic_read,
224 	.write		= generic_write,
225 	.console_write	= generic_console_write,
226 	.window_size	= generic_window_size,
227 	.free		= generic_free,
228 	.winch		= 1,
229 };
230