1 /* $OpenBSD: undgram_conclose.c,v 1.1 2021/12/10 00:33:25 mvs Exp $ */
2
3 /*
4 * Copyright (c) 2021 Vitaliy Makkoveev <mvs@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 /*
20 * Try to kill the datagram socket connected to the dying socket while
21 * it cleaning it's list of connected sockets. Incorrect handling of
22 * this case could produce kernel crash.
23 */
24
25 #include <sys/types.h>
26 #include <sys/select.h>
27 #include <sys/socket.h>
28 #include <sys/stat.h>
29 #include <sys/sysctl.h>
30 #include <sys/un.h>
31 #include <stdarg.h>
32 #include <stdio.h>
33 #include <err.h>
34 #include <pthread.h>
35 #include <string.h>
36 #include <time.h>
37 #include <unistd.h>
38
39 static pthread_mutex_t therr_mtx = PTHREAD_MUTEX_INITIALIZER;
40
41 static void
therr(int eval,const char * fmt,...)42 therr(int eval, const char *fmt, ...)
43 {
44 va_list ap;
45
46 pthread_mutex_lock(&therr_mtx);
47
48 va_start(ap, fmt);
49 verr(eval, fmt, ap);
50 va_end(ap);
51 }
52
53 static void
therrc(int eval,int code,const char * fmt,...)54 therrc(int eval, int code, const char *fmt, ...)
55 {
56 va_list ap;
57
58 pthread_mutex_lock(&therr_mtx);
59
60 va_start(ap, fmt);
61 verrc(eval, code, fmt, ap);
62 va_end(ap);
63 }
64
65 static void *
thr_close(void * arg)66 thr_close(void *arg)
67 {
68 struct sockaddr_un *sun = arg;
69 int s;
70
71 while (1) {
72 unlink(sun->sun_path);
73
74 if ((s = socket(AF_UNIX, SOCK_DGRAM, 0)) < 0)
75 therr(1, "socket");
76 if (bind(s, (struct sockaddr *)sun, sizeof(*sun)) < 0)
77 therr(1, "bind");
78 close(s);
79 }
80
81 return NULL;
82 }
83
84 static void *
thr_conn(void * arg)85 thr_conn(void *arg)
86 {
87 struct sockaddr_un *sun = arg;
88 int s;
89
90 while (1) {
91 if ((s = socket(AF_UNIX, SOCK_DGRAM, 0)) < 0)
92 therr(1, "socket");
93 connect(s, (struct sockaddr *)sun, sizeof(*sun));
94 close(s);
95 }
96
97 return NULL;
98 }
99
100 static struct sockaddr_un sun;
101
102 int
main(int argc,char * argv[])103 main(int argc, char *argv[])
104 {
105 struct timespec testtime = {
106 .tv_sec = 60,
107 .tv_nsec = 0,
108 };
109
110 int mib[2], ncpu;
111 size_t len;
112
113 pthread_t thr;
114 int error, i;
115
116 umask(0077);
117
118 if (argc == 2 && !strcmp(argv[1], "--infinite"))
119 testtime.tv_sec = (10 * 365 * 86400);
120
121 mib[0] = CTL_HW;
122 mib[1] = HW_NCPUONLINE;
123 len = sizeof(ncpu);
124
125 if (sysctl(mib, 2, &ncpu, &len, NULL, 0) < 0)
126 err(1, "sysctl");
127 if (ncpu <= 0)
128 errx(1, "Wrong number of CPUs online: %d", ncpu);
129
130 memset(&sun, 0, sizeof(sun));
131 sun.sun_len = sizeof(sun);
132 sun.sun_family = AF_UNIX;
133 snprintf(sun.sun_path, sizeof(sun.sun_path) - 1,
134 "undgram_conclose.socket");
135
136 if ((error = pthread_create(&thr, NULL, thr_close, &sun)))
137 therrc(1, error, "pthread_create");
138
139 for (i = 0; i < (ncpu * 4); ++i) {
140 if ((error = pthread_create(&thr, NULL, thr_conn, &sun)))
141 therrc(1, error, "pthread_create");
142 }
143
144 nanosleep(&testtime, NULL);
145
146 return 0;
147 }
148