xref: /openbmc/linux/tools/usb/usbip/src/usbip_bind.c (revision a06c488d)
1 /*
2  * Copyright (C) 2011 matt mooney <mfm@muteddisk.com>
3  *               2005-2007 Takahiro Hirofuchi
4  *
5  * This program is free software: you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation, either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU General Public License for more details.
14  *
15  * You should have received a copy of the GNU General Public License
16  * along with this program. If not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #include <libudev.h>
20 
21 #include <errno.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 
26 #include <getopt.h>
27 
28 #include "usbip_common.h"
29 #include "utils.h"
30 #include "usbip.h"
31 #include "sysfs_utils.h"
32 
33 enum unbind_status {
34 	UNBIND_ST_OK,
35 	UNBIND_ST_USBIP_HOST,
36 	UNBIND_ST_FAILED
37 };
38 
39 static const char usbip_bind_usage_string[] =
40 	"usbip bind <args>\n"
41 	"    -b, --busid=<busid>    Bind " USBIP_HOST_DRV_NAME ".ko to device "
42 	"on <busid>\n";
43 
44 void usbip_bind_usage(void)
45 {
46 	printf("usage: %s", usbip_bind_usage_string);
47 }
48 
49 /* call at unbound state */
50 static int bind_usbip(char *busid)
51 {
52 	char attr_name[] = "bind";
53 	char bind_attr_path[SYSFS_PATH_MAX];
54 	int rc = -1;
55 
56 	snprintf(bind_attr_path, sizeof(bind_attr_path), "%s/%s/%s/%s/%s/%s",
57 		 SYSFS_MNT_PATH, SYSFS_BUS_NAME, SYSFS_BUS_TYPE,
58 		 SYSFS_DRIVERS_NAME, USBIP_HOST_DRV_NAME, attr_name);
59 
60 	rc = write_sysfs_attribute(bind_attr_path, busid, strlen(busid));
61 	if (rc < 0) {
62 		err("error binding device %s to driver: %s", busid,
63 		    strerror(errno));
64 		return -1;
65 	}
66 
67 	return 0;
68 }
69 
70 /* buggy driver may cause dead lock */
71 static int unbind_other(char *busid)
72 {
73 	enum unbind_status status = UNBIND_ST_OK;
74 
75 	char attr_name[] = "unbind";
76 	char unbind_attr_path[SYSFS_PATH_MAX];
77 	int rc = -1;
78 
79 	struct udev *udev;
80 	struct udev_device *dev;
81 	const char *driver;
82 	const char *bDevClass;
83 
84 	/* Create libudev context. */
85 	udev = udev_new();
86 
87 	/* Get the device. */
88 	dev = udev_device_new_from_subsystem_sysname(udev, "usb", busid);
89 	if (!dev) {
90 		dbg("unable to find device with bus ID %s", busid);
91 		goto err_close_busid_dev;
92 	}
93 
94 	/* Check what kind of device it is. */
95 	bDevClass  = udev_device_get_sysattr_value(dev, "bDeviceClass");
96 	if (!bDevClass) {
97 		dbg("unable to get bDevClass device attribute");
98 		goto err_close_busid_dev;
99 	}
100 
101 	if (!strncmp(bDevClass, "09", strlen(bDevClass))) {
102 		dbg("skip unbinding of hub");
103 		goto err_close_busid_dev;
104 	}
105 
106 	/* Get the device driver. */
107 	driver = udev_device_get_driver(dev);
108 	if (!driver) {
109 		/* No driver bound to this device. */
110 		goto out;
111 	}
112 
113 	if (!strncmp(USBIP_HOST_DRV_NAME, driver,
114 				strlen(USBIP_HOST_DRV_NAME))) {
115 		/* Already bound to usbip-host. */
116 		status = UNBIND_ST_USBIP_HOST;
117 		goto out;
118 	}
119 
120 	/* Unbind device from driver. */
121 	snprintf(unbind_attr_path, sizeof(unbind_attr_path), "%s/%s/%s/%s/%s/%s",
122 		 SYSFS_MNT_PATH, SYSFS_BUS_NAME, SYSFS_BUS_TYPE,
123 		 SYSFS_DRIVERS_NAME, driver, attr_name);
124 
125 	rc = write_sysfs_attribute(unbind_attr_path, busid, strlen(busid));
126 	if (rc < 0) {
127 		err("error unbinding device %s from driver", busid);
128 		goto err_close_busid_dev;
129 	}
130 
131 	goto out;
132 
133 err_close_busid_dev:
134 	status = UNBIND_ST_FAILED;
135 out:
136 	udev_device_unref(dev);
137 	udev_unref(udev);
138 
139 	return status;
140 }
141 
142 static int bind_device(char *busid)
143 {
144 	int rc;
145 	struct udev *udev;
146 	struct udev_device *dev;
147 
148 	/* Check whether the device with this bus ID exists. */
149 	udev = udev_new();
150 	dev = udev_device_new_from_subsystem_sysname(udev, "usb", busid);
151 	if (!dev) {
152 		err("device with the specified bus ID does not exist");
153 		return -1;
154 	}
155 	udev_unref(udev);
156 
157 	rc = unbind_other(busid);
158 	if (rc == UNBIND_ST_FAILED) {
159 		err("could not unbind driver from device on busid %s", busid);
160 		return -1;
161 	} else if (rc == UNBIND_ST_USBIP_HOST) {
162 		err("device on busid %s is already bound to %s", busid,
163 		    USBIP_HOST_DRV_NAME);
164 		return -1;
165 	}
166 
167 	rc = modify_match_busid(busid, 1);
168 	if (rc < 0) {
169 		err("unable to bind device on %s", busid);
170 		return -1;
171 	}
172 
173 	rc = bind_usbip(busid);
174 	if (rc < 0) {
175 		err("could not bind device to %s", USBIP_HOST_DRV_NAME);
176 		modify_match_busid(busid, 0);
177 		return -1;
178 	}
179 
180 	info("bind device on busid %s: complete", busid);
181 
182 	return 0;
183 }
184 
185 int usbip_bind(int argc, char *argv[])
186 {
187 	static const struct option opts[] = {
188 		{ "busid", required_argument, NULL, 'b' },
189 		{ NULL,    0,                 NULL,  0  }
190 	};
191 
192 	int opt;
193 	int ret = -1;
194 
195 	for (;;) {
196 		opt = getopt_long(argc, argv, "b:", opts, NULL);
197 
198 		if (opt == -1)
199 			break;
200 
201 		switch (opt) {
202 		case 'b':
203 			ret = bind_device(optarg);
204 			goto out;
205 		default:
206 			goto err_out;
207 		}
208 	}
209 
210 err_out:
211 	usbip_bind_usage();
212 out:
213 	return ret;
214 }
215