xref: /openbmc/linux/arch/um/drivers/xterm.c (revision f9834f18)
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 	char *title;
22 	int device;
23 	int raw;
24 	struct termios tt;
25 };
26 
27 static void *xterm_init(char *str, int device, const struct chan_opts *opts)
28 {
29 	struct xterm_chan *data;
30 
31 	data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
32 	if (data == NULL)
33 		return NULL;
34 	*data = ((struct xterm_chan) { .pid 		= -1,
35 				       .helper_pid 	= -1,
36 				       .device 		= device,
37 				       .title 		= opts->xterm_title,
38 				       .raw  		= opts->raw } );
39 	return data;
40 }
41 
42 /* Only changed by xterm_setup, which is a setup */
43 static char *terminal_emulator = "xterm";
44 static char *title_switch = "-T";
45 static char *exec_switch = "-e";
46 
47 static int __init xterm_setup(char *line, int *add)
48 {
49 	*add = 0;
50 	terminal_emulator = line;
51 
52 	line = strchr(line, ',');
53 	if (line == NULL)
54 		return 0;
55 
56 	*line++ = '\0';
57 	if (*line)
58 		title_switch = line;
59 
60 	line = strchr(line, ',');
61 	if (line == NULL)
62 		return 0;
63 
64 	*line++ = '\0';
65 	if (*line)
66 		exec_switch = line;
67 
68 	return 0;
69 }
70 
71 __uml_setup("xterm=", xterm_setup,
72 "xterm=<terminal emulator>,<title switch>,<exec switch>\n"
73 "    Specifies an alternate terminal emulator to use for the debugger,\n"
74 "    consoles, and serial lines when they are attached to the xterm channel.\n"
75 "    The values are the terminal emulator binary, the switch it uses to set\n"
76 "    its title, and the switch it uses to execute a subprocess,\n"
77 "    respectively.  The title switch must have the form '<switch> title',\n"
78 "    not '<switch>=title'.  Similarly, the exec switch must have the form\n"
79 "    '<switch> command arg1 arg2 ...'.\n"
80 "    The default values are 'xterm=xterm,-T,-e'.  Values for gnome-terminal\n"
81 "    are 'xterm=gnome-terminal,-t,-x'.\n\n"
82 );
83 
84 static int xterm_open(int input, int output, int primary, void *d,
85 		      char **dev_out)
86 {
87 	struct xterm_chan *data = d;
88 	int pid, fd, new, err;
89 	char title[256], file[] = "/tmp/xterm-pipeXXXXXX";
90 	char *argv[] = { terminal_emulator, title_switch, title, exec_switch,
91 			 OS_LIB_PATH "/uml/port-helper", "-uml-socket",
92 			 file, NULL };
93 
94 	if (access(argv[4], X_OK) < 0)
95 		argv[4] = "port-helper";
96 
97 	/*
98 	 * Check that DISPLAY is set, this doesn't guarantee the xterm
99 	 * will work but w/o it we can be pretty sure it won't.
100 	 */
101 	if (getenv("DISPLAY") == NULL) {
102 		printk(UM_KERN_ERR "xterm_open: $DISPLAY not set.\n");
103 		return -ENODEV;
104 	}
105 
106 	/*
107 	 * This business of getting a descriptor to a temp file,
108 	 * deleting the file and closing the descriptor is just to get
109 	 * a known-unused name for the Unix socket that we really
110 	 * want.
111 	 */
112 	fd = mkstemp(file);
113 	if (fd < 0) {
114 		err = -errno;
115 		printk(UM_KERN_ERR "xterm_open : mkstemp failed, errno = %d\n",
116 		       errno);
117 		return err;
118 	}
119 
120 	if (unlink(file)) {
121 		err = -errno;
122 		printk(UM_KERN_ERR "xterm_open : unlink failed, errno = %d\n",
123 		       errno);
124 		close(fd);
125 		return err;
126 	}
127 	close(fd);
128 
129 	fd = os_create_unix_socket(file, sizeof(file), 1);
130 	if (fd < 0) {
131 		printk(UM_KERN_ERR "xterm_open : create_unix_socket failed, "
132 		       "errno = %d\n", -fd);
133 		return fd;
134 	}
135 
136 	sprintf(title, data->title, data->device);
137 	pid = run_helper(NULL, NULL, argv);
138 	if (pid < 0) {
139 		err = pid;
140 		printk(UM_KERN_ERR "xterm_open : run_helper failed, "
141 		       "errno = %d\n", -err);
142 		goto out_close1;
143 	}
144 
145 	err = os_set_fd_block(fd, 0);
146 	if (err < 0) {
147 		printk(UM_KERN_ERR "xterm_open : failed to set descriptor "
148 		       "non-blocking, err = %d\n", -err);
149 		goto out_kill;
150 	}
151 
152 	new = xterm_fd(fd, &data->helper_pid);
153 	if (new < 0) {
154 		err = new;
155 		printk(UM_KERN_ERR "xterm_open : os_rcv_fd failed, err = %d\n",
156 		       -err);
157 		goto out_kill;
158 	}
159 
160 	err = os_set_fd_block(new, 0);
161 	if (err) {
162 		printk(UM_KERN_ERR "xterm_open : failed to set xterm "
163 		       "descriptor non-blocking, err = %d\n", -err);
164 		goto out_close2;
165 	}
166 
167 	CATCH_EINTR(err = tcgetattr(new, &data->tt));
168 	if (err) {
169 		new = err;
170 		goto out_close2;
171 	}
172 
173 	if (data->raw) {
174 		err = raw(new);
175 		if (err) {
176 			new = err;
177 			goto out_close2;
178 		}
179 	}
180 
181 	unlink(file);
182 	data->pid = pid;
183 	*dev_out = NULL;
184 
185 	return new;
186 
187  out_close2:
188 	close(new);
189  out_kill:
190 	os_kill_process(pid, 1);
191  out_close1:
192 	close(fd);
193 
194 	return err;
195 }
196 
197 static void xterm_close(int fd, void *d)
198 {
199 	struct xterm_chan *data = d;
200 
201 	if (data->pid != -1)
202 		os_kill_process(data->pid, 1);
203 	data->pid = -1;
204 
205 	if (data->helper_pid != -1)
206 		os_kill_process(data->helper_pid, 0);
207 	data->helper_pid = -1;
208 
209 	os_close_file(fd);
210 }
211 
212 const struct chan_ops xterm_ops = {
213 	.type		= "xterm",
214 	.init		= xterm_init,
215 	.open		= xterm_open,
216 	.close		= xterm_close,
217 	.read		= generic_read,
218 	.write		= generic_write,
219 	.console_write	= generic_console_write,
220 	.window_size	= generic_window_size,
221 	.free		= generic_free,
222 	.winch		= 1,
223 };
224