1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2011 matt mooney <mfm@muteddisk.com>
4  *               2005-2007 Takahiro Hirofuchi
5  */
6 
7 #include <libudev.h>
8 
9 #include <errno.h>
10 #include <stdio.h>
11 #include <string.h>
12 
13 #include <getopt.h>
14 
15 #include "usbip_common.h"
16 #include "utils.h"
17 #include "usbip.h"
18 #include "sysfs_utils.h"
19 
20 static const char usbip_unbind_usage_string[] =
21 	"usbip unbind <args>\n"
22 	"    -b, --busid=<busid>    Unbind " USBIP_HOST_DRV_NAME ".ko from "
23 	"device on <busid>\n";
24 
usbip_unbind_usage(void)25 void usbip_unbind_usage(void)
26 {
27 	printf("usage: %s", usbip_unbind_usage_string);
28 }
29 
unbind_device(char * busid)30 static int unbind_device(char *busid)
31 {
32 	char bus_type[] = "usb";
33 	int rc, ret = -1;
34 
35 	char unbind_attr_name[] = "unbind";
36 	char unbind_attr_path[SYSFS_PATH_MAX];
37 	char rebind_attr_name[] = "rebind";
38 	char rebind_attr_path[SYSFS_PATH_MAX];
39 
40 	struct udev *udev;
41 	struct udev_device *dev;
42 	const char *driver;
43 
44 	/* Create libudev context. */
45 	udev = udev_new();
46 
47 	/* Check whether the device with this bus ID exists. */
48 	dev = udev_device_new_from_subsystem_sysname(udev, "usb", busid);
49 	if (!dev) {
50 		err("device with the specified bus ID does not exist");
51 		goto err_close_udev;
52 	}
53 
54 	/* Check whether the device is using usbip-host driver. */
55 	driver = udev_device_get_driver(dev);
56 	if (!driver || strcmp(driver, "usbip-host")) {
57 		err("device is not bound to usbip-host driver");
58 		goto err_close_udev;
59 	}
60 
61 	/* Unbind device from driver. */
62 	snprintf(unbind_attr_path, sizeof(unbind_attr_path), "%s/%s/%s/%s/%s/%s",
63 		 SYSFS_MNT_PATH, SYSFS_BUS_NAME, bus_type, SYSFS_DRIVERS_NAME,
64 		 USBIP_HOST_DRV_NAME, unbind_attr_name);
65 
66 	rc = write_sysfs_attribute(unbind_attr_path, busid, strlen(busid));
67 	if (rc < 0) {
68 		err("error unbinding device %s from driver", busid);
69 		goto err_close_udev;
70 	}
71 
72 	/* Notify driver of unbind. */
73 	rc = modify_match_busid(busid, 0);
74 	if (rc < 0) {
75 		err("unable to unbind device on %s", busid);
76 		goto err_close_udev;
77 	}
78 
79 	/* Trigger new probing. */
80 	snprintf(rebind_attr_path, sizeof(unbind_attr_path), "%s/%s/%s/%s/%s/%s",
81 			SYSFS_MNT_PATH, SYSFS_BUS_NAME, bus_type, SYSFS_DRIVERS_NAME,
82 			USBIP_HOST_DRV_NAME, rebind_attr_name);
83 
84 	rc = write_sysfs_attribute(rebind_attr_path, busid, strlen(busid));
85 	if (rc < 0) {
86 		err("error rebinding");
87 		goto err_close_udev;
88 	}
89 
90 	ret = 0;
91 	info("unbind device on busid %s: complete", busid);
92 
93 err_close_udev:
94 	udev_device_unref(dev);
95 	udev_unref(udev);
96 
97 	return ret;
98 }
99 
usbip_unbind(int argc,char * argv[])100 int usbip_unbind(int argc, char *argv[])
101 {
102 	static const struct option opts[] = {
103 		{ "busid", required_argument, NULL, 'b' },
104 		{ NULL,    0,                 NULL,  0  }
105 	};
106 
107 	int opt;
108 	int ret = -1;
109 
110 	for (;;) {
111 		opt = getopt_long(argc, argv, "b:", opts, NULL);
112 
113 		if (opt == -1)
114 			break;
115 
116 		switch (opt) {
117 		case 'b':
118 			ret = unbind_device(optarg);
119 			goto out;
120 		default:
121 			goto err_out;
122 		}
123 	}
124 
125 err_out:
126 	usbip_unbind_usage();
127 out:
128 	return ret;
129 }
130