xref: /openbmc/linux/arch/um/drivers/xterm.c (revision 99a15348)
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 = "xterm";
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=xterm,-T,-e'.  Values for gnome-terminal\n"
83 "    are 'xterm=gnome-terminal,-t,-x'.\n\n"
84 );
85 
86 static int xterm_open(int input, int output, int primary, void *d,
87 		      char **dev_out)
88 {
89 	struct xterm_chan *data = d;
90 	int pid, fd, new, err;
91 	char title[256], file[] = "/tmp/xterm-pipeXXXXXX";
92 	char *argv[] = { terminal_emulator, title_switch, title, exec_switch,
93 			 OS_LIB_PATH "/uml/port-helper", "-uml-socket",
94 			 file, NULL };
95 
96 	if (access(argv[4], X_OK) < 0)
97 		argv[4] = "port-helper";
98 
99 	/*
100 	 * Check that DISPLAY is set, this doesn't guarantee the xterm
101 	 * will work but w/o it we can be pretty sure it won't.
102 	 */
103 	if (getenv("DISPLAY") == NULL) {
104 		printk(UM_KERN_ERR "xterm_open: $DISPLAY not set.\n");
105 		return -ENODEV;
106 	}
107 
108 	/*
109 	 * This business of getting a descriptor to a temp file,
110 	 * deleting the file and closing the descriptor is just to get
111 	 * a known-unused name for the Unix socket that we really
112 	 * want.
113 	 */
114 	fd = mkstemp(file);
115 	if (fd < 0) {
116 		err = -errno;
117 		printk(UM_KERN_ERR "xterm_open : mkstemp failed, errno = %d\n",
118 		       errno);
119 		return err;
120 	}
121 
122 	if (unlink(file)) {
123 		err = -errno;
124 		printk(UM_KERN_ERR "xterm_open : unlink failed, errno = %d\n",
125 		       errno);
126 		close(fd);
127 		return err;
128 	}
129 	close(fd);
130 
131 	fd = os_create_unix_socket(file, sizeof(file), 1);
132 	if (fd < 0) {
133 		printk(UM_KERN_ERR "xterm_open : create_unix_socket failed, "
134 		       "errno = %d\n", -fd);
135 		return fd;
136 	}
137 
138 	sprintf(title, data->title, data->device);
139 	pid = run_helper(NULL, NULL, argv);
140 	if (pid < 0) {
141 		err = pid;
142 		printk(UM_KERN_ERR "xterm_open : run_helper failed, "
143 		       "errno = %d\n", -err);
144 		goto out_close1;
145 	}
146 
147 	err = os_set_fd_block(fd, 0);
148 	if (err < 0) {
149 		printk(UM_KERN_ERR "xterm_open : failed to set descriptor "
150 		       "non-blocking, err = %d\n", -err);
151 		goto out_kill;
152 	}
153 
154 	data->chan_fd = fd;
155 	new = xterm_fd(fd, &data->helper_pid);
156 	if (new < 0) {
157 		err = new;
158 		printk(UM_KERN_ERR "xterm_open : os_rcv_fd failed, err = %d\n",
159 		       -err);
160 		goto out_kill;
161 	}
162 
163 	err = os_set_fd_block(new, 0);
164 	if (err) {
165 		printk(UM_KERN_ERR "xterm_open : failed to set xterm "
166 		       "descriptor non-blocking, err = %d\n", -err);
167 		goto out_close2;
168 	}
169 
170 	CATCH_EINTR(err = tcgetattr(new, &data->tt));
171 	if (err) {
172 		new = err;
173 		goto out_close2;
174 	}
175 
176 	if (data->raw) {
177 		err = raw(new);
178 		if (err) {
179 			new = err;
180 			goto out_close2;
181 		}
182 	}
183 
184 	unlink(file);
185 	data->pid = pid;
186 	*dev_out = NULL;
187 
188 	return new;
189 
190  out_close2:
191 	close(new);
192  out_kill:
193 	os_kill_process(pid, 1);
194  out_close1:
195 	close(fd);
196 
197 	return err;
198 }
199 
200 static void xterm_close(int fd, void *d)
201 {
202 	struct xterm_chan *data = d;
203 
204 	if (data->pid != -1)
205 		os_kill_process(data->pid, 1);
206 	data->pid = -1;
207 
208 	if (data->helper_pid != -1)
209 		os_kill_process(data->helper_pid, 0);
210 	data->helper_pid = -1;
211 
212 	if (data->chan_fd != -1)
213 		os_close_file(data->chan_fd);
214 	os_close_file(fd);
215 }
216 
217 const struct chan_ops xterm_ops = {
218 	.type		= "xterm",
219 	.init		= xterm_init,
220 	.open		= xterm_open,
221 	.close		= xterm_close,
222 	.read		= generic_read,
223 	.write		= generic_write,
224 	.console_write	= generic_console_write,
225 	.window_size	= generic_window_size,
226 	.free		= generic_free,
227 	.winch		= 1,
228 };
229