xref: /linux/arch/um/drivers/xterm.c (revision cfc4ca8986bb1f6182da6cd7bb57f228590b4643)
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 
xterm_init(char * str,int device,const struct chan_opts * opts)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 
xterm_setup(char * line,int * add)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,--'.\n\n"
85 );
86 
xterm_open(int input,int output,int primary,void * d,char ** dev_out)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 	/* Ensure we are running on Xorg or Wayland. */
101 	if (!getenv("DISPLAY") && !getenv("WAYLAND_DISPLAY")) {
102 		printk(UM_KERN_ERR "xterm_open : neither $DISPLAY nor $WAYLAND_DISPLAY is 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 	data->chan_fd = fd;
153 	new = xterm_fd(fd, &data->helper_pid);
154 	if (new < 0) {
155 		err = new;
156 		printk(UM_KERN_ERR "xterm_open : xterm_fd failed, err = %d\n",
157 		       -err);
158 		goto out_kill;
159 	}
160 
161 	err = os_set_fd_block(new, 0);
162 	if (err) {
163 		printk(UM_KERN_ERR "xterm_open : failed to set xterm "
164 		       "descriptor non-blocking, err = %d\n", -err);
165 		goto out_close2;
166 	}
167 
168 	CATCH_EINTR(err = tcgetattr(new, &data->tt));
169 	if (err) {
170 		new = err;
171 		goto out_close2;
172 	}
173 
174 	if (data->raw) {
175 		err = raw(new);
176 		if (err) {
177 			new = err;
178 			goto out_close2;
179 		}
180 	}
181 
182 	unlink(file);
183 	data->pid = pid;
184 	*dev_out = NULL;
185 
186 	return new;
187 
188  out_close2:
189 	close(new);
190  out_kill:
191 	os_kill_process(pid, 1);
192  out_close1:
193 	close(fd);
194 
195 	return err;
196 }
197 
xterm_close(int fd,void * d)198 static void xterm_close(int fd, void *d)
199 {
200 	struct xterm_chan *data = d;
201 
202 	if (data->pid != -1)
203 		os_kill_process(data->pid, 1);
204 	data->pid = -1;
205 
206 	if (data->helper_pid != -1)
207 		os_kill_process(data->helper_pid, 0);
208 	data->helper_pid = -1;
209 
210 	if (data->chan_fd != -1)
211 		os_close_file(data->chan_fd);
212 	os_close_file(fd);
213 }
214 
215 const struct chan_ops xterm_ops = {
216 	.type		= "xterm",
217 	.init		= xterm_init,
218 	.open		= xterm_open,
219 	.close		= xterm_close,
220 	.read		= generic_read,
221 	.write		= generic_write,
222 	.console_write	= generic_console_write,
223 	.window_size	= generic_window_size,
224 	.free		= generic_free,
225 	.winch		= 1,
226 };
227