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1 /*
2  * Check decoding of threads when a non-leader thread invokes execve.
3  *
4  * Copyright (c) 2016 Dmitry V. Levin <ldv@altlinux.org>
5  * Copyright (c) 2016-2017 The strace developers.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include "tests.h"
32 #include <asm/unistd.h>
33 #include <errno.h>
34 #include <pthread.h>
35 #include <signal.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <time.h>
39 #include <unistd.h>
40 
41 static pid_t leader;
42 static pid_t tid;
43 
44 static void
handler(int signo)45 handler(int signo)
46 {
47 }
48 
49 static unsigned int sigsetsize;
50 static long
k_sigsuspend(const sigset_t * const set)51 k_sigsuspend(const sigset_t *const set)
52 {
53 	return syscall(__NR_rt_sigsuspend, set, sigsetsize);
54 }
55 
56 static pid_t
k_gettid(void)57 k_gettid(void)
58 {
59 	return syscall(__NR_gettid);
60 }
61 
62 static void
get_sigsetsize(void)63 get_sigsetsize(void)
64 {
65 	static const struct sigaction sa = { .sa_handler = handler };
66 	if (sigaction(SIGUSR1, &sa, NULL))
67 		perror_msg_and_fail("sigaction");
68 
69 	sigset_t mask;
70 	sigemptyset(&mask);
71 	sigaddset(&mask, SIGUSR1);
72 	if (sigprocmask(SIG_BLOCK, &mask, NULL))
73 		perror_msg_and_fail("sigprocmask");
74 
75 	raise(SIGUSR1);
76 
77 	sigemptyset(&mask);
78 	for (sigsetsize = sizeof(mask) / sizeof(long);
79 	     sigsetsize; sigsetsize >>= 1) {
80 		long rc = k_sigsuspend(&mask);
81 		if (!rc)
82 			error_msg_and_fail("rt_sigsuspend");
83 		if (EINTR == errno)
84 			break;
85 		printf("%-5d rt_sigsuspend(%p, %u) = %s\n",
86 		       leader, &mask, sigsetsize, sprintrc(rc));
87 	}
88 	if (!sigsetsize)
89 		perror_msg_and_fail("rt_sigsuspend");
90 	printf("%-5d rt_sigsuspend([], %u) = ? ERESTARTNOHAND"
91 	       " (To be restarted if no handler)\n", leader, sigsetsize);
92 }
93 
94 enum {
95 	ACTION_exit = 0,
96 	ACTION_rt_sigsuspend,
97 	ACTION_nanosleep,
98 	NUMBER_OF_ACTIONS
99 };
100 
101 static const unsigned int NUMBER_OF_ITERATIONS = 1;
102 static unsigned int action;
103 static int fds[2];
104 
105 static unsigned int
arglen(char ** args)106 arglen(char **args)
107 {
108 	char **p;
109 
110 	for (p = args; *p; ++p)
111 		;
112 
113 	return p - args;
114 }
115 
116 static void *
thread(void * arg)117 thread(void *arg)
118 {
119 	tid = k_gettid();
120 
121 	static char buf[sizeof(action) * 3];
122 	sprintf(buf, "%u", action + 1);
123 
124 	char **argv = arg;
125 	argv[2] = buf;
126 
127 	if (read(fds[0], fds, sizeof(fds[0])))
128 		perror_msg_and_fail("execve");
129 
130 	struct timespec ts = { .tv_nsec = 100000000 };
131 	(void) clock_nanosleep(CLOCK_REALTIME, 0, &ts, NULL);
132 
133 	ts.tv_nsec = 12345;
134 	printf("%-5d nanosleep({tv_sec=0, tv_nsec=%u}, NULL) = 0\n",
135 	       tid, (unsigned int) ts.tv_nsec);
136 
137 	switch (action % NUMBER_OF_ACTIONS) {
138 		case ACTION_exit:
139 			printf("%-5d execve(\"%s\", [\"%s\", \"%s\", \"%s\"]"
140 			       ", %p /* %u vars */ <pid changed to %u ...>\n",
141 			       tid, argv[0], argv[0], argv[1], argv[2],
142 			       environ, arglen(environ), leader);
143 			break;
144 		case ACTION_rt_sigsuspend:
145 			printf("%-5d execve(\"%s\", [\"%s\", \"%s\", \"%s\"]"
146 			       ", %p /* %u vars */ <unfinished ...>\n"
147 			       "%-5d <... rt_sigsuspend resumed>) = ?\n",
148 			       tid, argv[0], argv[0], argv[1], argv[2],
149 			       environ, arglen(environ),
150 			       leader);
151 			break;
152 		case ACTION_nanosleep:
153 			printf("%-5d execve(\"%s\", [\"%s\", \"%s\", \"%s\"]"
154 			       ", %p /* %u vars */ <unfinished ...>\n"
155 			       "%-5d <... nanosleep resumed> <unfinished ...>)"
156 			       " = ?\n",
157 			       tid, argv[0], argv[0], argv[1], argv[2],
158 			       environ, arglen(environ),
159 			       leader);
160 			break;
161 	}
162 
163 	printf("%-5d +++ superseded by execve in pid %u +++\n"
164 	       "%-5d <... execve resumed> ) = 0\n",
165 	       leader, tid,
166 	       leader);
167 
168 	(void) nanosleep(&ts, NULL);
169 	execve(argv[0], argv, environ);
170 	perror_msg_and_fail("execve");
171 }
172 
173 int
main(int ac,char ** av)174 main(int ac, char **av)
175 {
176 	setvbuf(stdout, NULL, _IONBF, 0);
177 	leader = getpid();
178 
179 	if (ac < 3) {
180 		struct timespec ts = { .tv_nsec = 1 };
181 		if (clock_nanosleep(CLOCK_REALTIME, 0, &ts, NULL))
182 			perror_msg_and_skip("clock_nanosleep CLOCK_REALTIME");
183 
184 		get_sigsetsize();
185 		static char buf[sizeof(sigsetsize) * 3];
186 		sprintf(buf, "%u", sigsetsize);
187 
188 		char *argv[] = { av[0], buf, (char *) "0", NULL };
189 		printf("%-5d execve(\"%s\", [\"%s\", \"%s\", \"%s\"]"
190 		       ", %p /* %u vars */) = 0\n",
191 		       leader, argv[0], argv[0], argv[1], argv[2],
192 		       environ, arglen(environ));
193 		execve(argv[0], argv, environ);
194 		perror_msg_and_fail("execve");
195 	}
196 
197 	sigsetsize = atoi(av[1]);
198 	action = atoi(av[2]);
199 
200 	if (action >= NUMBER_OF_ACTIONS * NUMBER_OF_ITERATIONS) {
201 		printf("%-5d +++ exited with 0 +++\n", leader);
202 		return 0;
203 	}
204 
205 	if (pipe(fds))
206 		perror_msg_and_fail("pipe");
207 
208 	pthread_t t;
209 	errno = pthread_create(&t, NULL, thread, av);
210 	if (errno)
211 		perror_msg_and_fail("pthread_create");
212 
213 	struct timespec ts = { .tv_sec = 123 };
214 	sigset_t mask;
215 	sigemptyset(&mask);
216 
217 	static char leader_str[sizeof(leader) * 3];
218 	int leader_str_len =
219 		snprintf(leader_str, sizeof(leader_str), "%-5d", leader);
220 
221 	switch (action % NUMBER_OF_ACTIONS) {
222 		case ACTION_exit:
223 			printf("%s exit(42)%*s= ?\n", leader_str,
224 			       (int) sizeof(leader_str) - leader_str_len, " ");
225 			close(fds[1]);
226 			(void) syscall(__NR_exit, 42);
227 			break;
228 		case ACTION_rt_sigsuspend:
229 			printf("%s rt_sigsuspend([], %u <unfinished ...>\n",
230 			       leader_str, sigsetsize);
231 			close(fds[1]);
232 			(void) k_sigsuspend(&mask);
233 			break;
234 		case ACTION_nanosleep:
235 			printf("%s nanosleep({tv_sec=%u, tv_nsec=0}"
236 			       ",  <unfinished ...>\n",
237 			       leader_str, (unsigned int) ts.tv_sec);
238 			close(fds[1]);
239 			(void) nanosleep(&ts, 0);
240 			break;
241 	}
242 
243 	return 1;
244 }
245