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1 /***
2   This file is part of systemd.
3 
4   Copyright 2003-2004 Greg Kroah-Hartman <greg@kroah.com>
5   Copyright 2004-2012 Kay Sievers <kay@vrfy.org>
6 
7   systemd is free software; you can redistribute it and/or modify it
8   under the terms of the GNU Lesser General Public License as published by
9   the Free Software Foundation; either version 2.1 of the License, or
10   (at your option) any later version.
11 
12   systemd is distributed in the hope that it will be useful, but
13   WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15   Lesser General Public License for more details.
16 
17   You should have received a copy of the GNU Lesser General Public License
18   along with systemd; If not, see <http://www.gnu.org/licenses/>.
19 ***/
20 
21 #include <stdio.h>
22 #include <stddef.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <fcntl.h>
26 #include <ctype.h>
27 #include <errno.h>
28 #include <unistd.h>
29 #include <grp.h>
30 #include <sched.h>
31 #include <sys/mount.h>
32 #include <sys/signalfd.h>
33 
34 #include "missing.h"
35 #include "udev.h"
36 #include "udev-util.h"
37 
38 #ifndef HAVE_UNSHARE
39 #include <sys/syscall.h>
40 /* Provide our own replacement with local reach*/
unshare(int x)41 static inline int unshare (int x) { return syscall(SYS_unshare, x); }
42 #endif
43 
44 #ifndef _USE_GNU
45 /* Make sure CLONE_NEWNS macro is available */
46 #include <linux/sched.h>
47 #endif
48 
fake_filesystems(void)49 static int fake_filesystems(void) {
50         static const struct fakefs {
51                 const char *src;
52                 const char *target;
53                 const char *error;
54         } fakefss[] = {
55                 { "test/sys", "/sys",                   "failed to mount test /sys" },
56                 { "test/dev", "/dev",                   "failed to mount test /dev" },
57                 { "test/run", UDEV_ROOT_RUN,            "failed to mount test " UDEV_ROOT_RUN },
58                 { "test/run", "/etc/udev/rules.d",      "failed to mount empty /etc/udev/rules.d" },
59                 { "test/run", "/lib/udev/rules.d",      "failed to mount empty /lib/udev/rules.d" },
60         };
61         unsigned int i;
62         int err;
63 
64         err = unshare(CLONE_NEWNS);
65         if (err < 0) {
66                 err = -errno;
67                 fprintf(stderr, "failed to call unshare(): %m\n");
68                 goto out;
69         }
70 
71         if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) < 0) {
72                 err = -errno;
73                 fprintf(stderr, "failed to mount / as private: %m\n");
74                 goto out;
75         }
76 
77         for (i = 0; i < ELEMENTSOF(fakefss); i++) {
78                 err = mount(fakefss[i].src, fakefss[i].target, NULL, MS_BIND, NULL);
79                 if (err < 0) {
80                         err = -errno;
81                         fprintf(stderr, "%s %m", fakefss[i].error);
82                         return err;
83                 }
84         }
85 out:
86         return err;
87 }
88 
main(int argc,char * argv[])89 int main(int argc, char *argv[]) {
90         _cleanup_udev_unref_ struct udev *udev = NULL;
91         _cleanup_udev_event_unref_ struct udev_event *event = NULL;
92         _cleanup_udev_device_unref_ struct udev_device *dev = NULL;
93         _cleanup_udev_rules_unref_ struct udev_rules *rules = NULL;
94         char syspath[UTIL_PATH_SIZE];
95         const char *devpath;
96         const char *action;
97         sigset_t mask, sigmask_orig;
98         int err;
99 
100         err = fake_filesystems();
101         if (err < 0)
102                 return EXIT_FAILURE;
103 
104         udev = udev_new();
105         if (udev == NULL)
106                 return EXIT_FAILURE;
107 
108         log_debug("version %s", VERSION);
109         mac_selinux_init("/dev");
110 
111         sigprocmask(SIG_SETMASK, NULL, &sigmask_orig);
112 
113         action = argv[1];
114         if (action == NULL) {
115                 log_error("action missing");
116                 goto out;
117         }
118 
119         devpath = argv[2];
120         if (devpath == NULL) {
121                 log_error("devpath missing");
122                 goto out;
123         }
124 
125         rules = udev_rules_new(udev, 1);
126 
127         strscpyl(syspath, sizeof(syspath), "/sys", devpath, NULL);
128         dev = udev_device_new_from_synthetic_event(udev, syspath, action);
129         if (dev == NULL) {
130                 log_debug("unknown device '%s'", devpath);
131                 goto out;
132         }
133 
134         event = udev_event_new(dev);
135 
136         sigfillset(&mask);
137         sigprocmask(SIG_SETMASK, &mask, &sigmask_orig);
138         event->fd_signal = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
139         if (event->fd_signal < 0) {
140                 fprintf(stderr, "error creating signalfd\n");
141                 goto out;
142         }
143 
144         /* do what devtmpfs usually provides us */
145         if (udev_device_get_devnode(dev) != NULL) {
146                 mode_t mode = 0600;
147 
148                 if (streq(udev_device_get_subsystem(dev), "block"))
149                         mode |= S_IFBLK;
150                 else
151                         mode |= S_IFCHR;
152 
153                 if (!streq(action, "remove")) {
154                         mkdir_parents_label(udev_device_get_devnode(dev), 0755);
155                         mknod(udev_device_get_devnode(dev), mode, udev_device_get_devnum(dev));
156                 } else {
157                         unlink(udev_device_get_devnode(dev));
158                         rmdir_parents(udev_device_get_devnode(dev), "/");
159                 }
160         }
161 
162         udev_event_execute_rules(event,
163                                  3 * USEC_PER_SEC, USEC_PER_SEC,
164                                  NULL,
165                                  rules,
166                                  &sigmask_orig);
167         udev_event_execute_run(event,
168                                3 * USEC_PER_SEC, USEC_PER_SEC,
169                                NULL);
170 out:
171         if (event != NULL && event->fd_signal >= 0)
172                 close(event->fd_signal);
173         mac_selinux_finish();
174 
175         return err ? EXIT_FAILURE : EXIT_SUCCESS;
176 }
177