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1 | /* | |
2 | * udev-remove.c | |
3 | * | |
4 | * Userspace devfs | |
5 | * | |
6 | * Copyright (C) 2003 Greg Kroah-Hartman <greg@kroah.com> | |
7 | * | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify it | |
10 | * under the terms of the GNU General Public License as published by the | |
11 | * Free Software Foundation version 2 of the License. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, but | |
14 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License along | |
19 | * with this program; if not, write to the Free Software Foundation, Inc., | |
20 | * 675 Mass Ave, Cambridge, MA 02139, USA. | |
21 | * | |
22 | */ | |
23 | ||
24 | #include <stdlib.h> | |
25 | #include <string.h> | |
26 | #include <stdio.h> | |
27 | #include <fcntl.h> | |
28 | #include <unistd.h> | |
29 | #include <errno.h> | |
30 | ||
31 | #include "udev.h" | |
32 | #include "udev_lib.h" | |
33 | #include "udev_version.h" | |
34 | #include "logging.h" | |
35 | #include "namedev.h" | |
36 | #include "udevdb.h" | |
37 | ||
38 | static int delete_path(char *path) | |
39 | { | |
40 | char *pos; | |
41 | int retval; | |
42 | ||
43 | pos = strrchr(path, '/'); | |
44 | while (1) { | |
45 | *pos = '\0'; | |
46 | pos = strrchr(path, '/'); | |
47 | ||
48 | /* don't remove the last one */ | |
49 | if ((pos == path) || (pos == NULL)) | |
50 | break; | |
51 | ||
52 | /* remove if empty */ | |
53 | retval = rmdir(path); | |
54 | if (errno == ENOENT) | |
55 | retval = 0; | |
56 | if (retval) { | |
57 | if (errno == ENOTEMPTY) | |
58 | return 0; | |
59 | dbg("rmdir(%s) failed with error '%s'", | |
60 | path, strerror(errno)); | |
61 | break; | |
62 | } | |
63 | dbg("removed '%s'", path); | |
64 | } | |
65 | return 0; | |
66 | } | |
67 | ||
68 | /** Remove all permissions on the device node, before | |
69 | * unlinking it. This fixes a security issue. | |
70 | * If the user created a hard-link to the device node, | |
71 | * he can't use it any longer, because he lost permission | |
72 | * to do so. | |
73 | */ | |
74 | static int secure_unlink(const char *filename) | |
75 | { | |
76 | int retval; | |
77 | ||
78 | retval = chown(filename, 0, 0); | |
79 | if (retval) { | |
80 | dbg("chown(%s, 0, 0) failed with error '%s'", | |
81 | filename, strerror(errno)); | |
82 | /* We continue nevertheless. | |
83 | * I think it's very unlikely for chown | |
84 | * to fail here, if the file exists. | |
85 | */ | |
86 | } | |
87 | retval = chmod(filename, 0000); | |
88 | if (retval) { | |
89 | dbg("chmod(%s, 0000) failed with error '%s'", | |
90 | filename, strerror(errno)); | |
91 | /* We continue nevertheless. */ | |
92 | } | |
93 | retval = unlink(filename); | |
94 | if (errno == ENOENT) | |
95 | retval = 0; | |
96 | if (retval) { | |
97 | dbg("unlink(%s) failed with error '%s'", | |
98 | filename, strerror(errno)); | |
99 | } | |
100 | return retval; | |
101 | } | |
102 | ||
103 | static int delete_node(struct udevice *dev) | |
104 | { | |
105 | char filename[NAME_SIZE]; | |
106 | char linkname[NAME_SIZE]; | |
107 | char partitionname[NAME_SIZE]; | |
108 | int retval; | |
109 | int i; | |
110 | char *pos; | |
111 | int len; | |
112 | ||
113 | strfieldcpy(filename, udev_root); | |
114 | strfieldcat(filename, dev->name); | |
115 | ||
116 | info("removing device node '%s'", filename); | |
117 | retval = secure_unlink(filename); | |
118 | if (retval) | |
119 | return retval; | |
120 | ||
121 | /* remove partition nodes */ | |
122 | if (dev->partitions > 0) { | |
123 | info("removing partitions '%s[1-%i]'", filename, dev->partitions); | |
124 | for (i = 1; i <= dev->partitions; i++) { | |
125 | strfieldcpy(partitionname, filename); | |
126 | strintcat(partitionname, i); | |
127 | secure_unlink(partitionname); | |
128 | } | |
129 | } | |
130 | ||
131 | /* remove subdirectories */ | |
132 | if (strchr(dev->name, '/')) | |
133 | delete_path(filename); | |
134 | ||
135 | foreach_strpart(dev->symlink, " ", pos, len) { | |
136 | strfieldcpymax(linkname, pos, len+1); | |
137 | strfieldcpy(filename, udev_root); | |
138 | strfieldcat(filename, linkname); | |
139 | ||
140 | dbg("unlinking symlink '%s'", filename); | |
141 | retval = unlink(filename); | |
142 | if (errno == ENOENT) | |
143 | retval = 0; | |
144 | if (retval) { | |
145 | dbg("unlink(%s) failed with error '%s'", | |
146 | filename, strerror(errno)); | |
147 | return retval; | |
148 | } | |
149 | if (strchr(dev->symlink, '/')) { | |
150 | delete_path(filename); | |
151 | } | |
152 | } | |
153 | ||
154 | return retval; | |
155 | } | |
156 | ||
157 | /* | |
158 | * Look up the sysfs path in the database to see if we have named this device | |
159 | * something different from the kernel name. If we have, us it. If not, use | |
160 | * the default kernel name for lack of anything else to know to do. | |
161 | */ | |
162 | int udev_remove_device(char *path, char *subsystem) | |
163 | { | |
164 | struct udevice dev; | |
165 | char *temp; | |
166 | int retval; | |
167 | ||
168 | memset(&dev, 0x00, sizeof(dev)); | |
169 | ||
170 | retval = udevdb_get_dev(path, &dev); | |
171 | if (retval != 0) { | |
172 | dbg("'%s' not found in database, falling back on default name", path); | |
173 | temp = strrchr(path, '/'); | |
174 | if (temp == NULL) | |
175 | return -ENODEV; | |
176 | strfieldcpy(dev.name, &temp[1]); | |
177 | } | |
178 | dbg("name='%s'", dev.name); | |
179 | ||
180 | dev.type = get_device_type(path, subsystem); | |
181 | dev_d_send(&dev, subsystem, path); | |
182 | udevdb_delete_dev(path); | |
183 | ||
184 | if (dev.type == 'b' || dev.type == 'c') | |
185 | retval = delete_node(&dev); | |
186 | else if (dev.type == 'n') | |
187 | retval = 0; | |
188 | ||
189 | return retval; | |
190 | } |