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 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 *    derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include "tests.h"
31#include <asm/unistd.h>
32#include <errno.h>
33#include <pthread.h>
34#include <signal.h>
35#include <stdio.h>
36#include <stdlib.h>
37#include <time.h>
38#include <unistd.h>
39
40static pid_t leader;
41static pid_t tid;
42
43static void
44handler(int signo)
45{
46}
47
48static unsigned int sigsetsize;
49static long
50k_sigsuspend(const sigset_t *const set)
51{
52	return syscall(__NR_rt_sigsuspend, set, sigsetsize);
53}
54
55static pid_t
56k_gettid(void)
57{
58	return syscall(__NR_gettid);
59}
60
61static void
62get_sigsetsize(void)
63{
64	static const struct sigaction sa = { .sa_handler = handler };
65	if (sigaction(SIGUSR1, &sa, NULL))
66		perror_msg_and_fail("sigaction");
67
68	sigset_t mask;
69	sigemptyset(&mask);
70	sigaddset(&mask, SIGUSR1);
71	if (sigprocmask(SIG_BLOCK, &mask, NULL))
72		perror_msg_and_fail("sigprocmask");
73
74	raise(SIGUSR1);
75
76	sigemptyset(&mask);
77	for (sigsetsize = sizeof(mask) / sizeof(long);
78	     sigsetsize; sigsetsize >>= 1) {
79		long rc = k_sigsuspend(&mask);
80		if (!rc)
81			error_msg_and_fail("rt_sigsuspend");
82		if (EINTR == errno)
83			break;
84		printf("%-5d rt_sigsuspend(%p, %u) = %s\n",
85		       leader, &mask, sigsetsize, sprintrc(rc));
86	}
87	if (!sigsetsize)
88		perror_msg_and_fail("rt_sigsuspend");
89	printf("%-5d rt_sigsuspend([], %u) = ? ERESTARTNOHAND"
90	       " (To be restarted if no handler)\n", leader, sigsetsize);
91}
92
93enum {
94	ACTION_exit = 0,
95	ACTION_rt_sigsuspend,
96	ACTION_nanosleep,
97	NUMBER_OF_ACTIONS
98};
99
100static const unsigned int NUMBER_OF_ITERATIONS = 1;
101static unsigned int action;
102static int fds[2];
103
104static unsigned int
105arglen(char **args)
106{
107	char **p;
108
109	for (p = args; *p; ++p)
110		;
111
112	return p - args;
113}
114
115static void *
116thread(void *arg)
117{
118	tid = k_gettid();
119
120	static char buf[sizeof(action) * 3];
121	sprintf(buf, "%u", action + 1);
122
123	char **argv = arg;
124	argv[2] = buf;
125
126	if (read(fds[0], fds, sizeof(fds[0])))
127		perror_msg_and_fail("execve");
128
129	struct timespec ts = { .tv_nsec = 100000000 };
130	(void) clock_nanosleep(CLOCK_REALTIME, 0, &ts, NULL);
131
132	ts.tv_nsec = 12345;
133	printf("%-5d nanosleep({tv_sec=0, tv_nsec=%u}, NULL) = 0\n",
134	       tid, (unsigned int) ts.tv_nsec);
135
136	switch (action % NUMBER_OF_ACTIONS) {
137		case ACTION_exit:
138			printf("%-5d execve(\"%s\", [\"%s\", \"%s\", \"%s\"]"
139			       ", [/* %u vars */] <pid changed to %u ...>\n",
140			       tid, argv[0], argv[0], argv[1], argv[2],
141			       arglen(environ), leader);
142			break;
143		case ACTION_rt_sigsuspend:
144			printf("%-5d execve(\"%s\", [\"%s\", \"%s\", \"%s\"]"
145			       ", [/* %u vars */] <unfinished ...>\n"
146			       "%-5d <... rt_sigsuspend resumed>) = ?\n",
147			       tid, argv[0], argv[0], argv[1], argv[2],
148			       arglen(environ),
149			       leader);
150			break;
151		case ACTION_nanosleep:
152			printf("%-5d execve(\"%s\", [\"%s\", \"%s\", \"%s\"]"
153			       ", [/* %u vars */] <unfinished ...>\n"
154			       "%-5d <... nanosleep resumed> <unfinished ...>)"
155			       " = ?\n",
156			       tid, argv[0], argv[0], argv[1], argv[2],
157			       arglen(environ),
158			       leader);
159			break;
160	}
161
162	printf("%-5d +++ superseded by execve in pid %u +++\n"
163	       "%-5d <... execve resumed> ) = 0\n",
164	       leader, tid,
165	       leader);
166
167	(void) nanosleep(&ts, NULL);
168	execve(argv[0], argv, environ);
169	perror_msg_and_fail("execve");
170}
171
172int
173main(int ac, char **av)
174{
175	setvbuf(stdout, NULL, _IONBF, 0);
176	leader = getpid();
177
178	if (ac < 3) {
179		struct timespec ts = { .tv_nsec = 1 };
180		if (clock_nanosleep(CLOCK_REALTIME, 0, &ts, NULL))
181			perror_msg_and_skip("clock_nanosleep CLOCK_REALTIME");
182
183		printf("%-5d execve(\"%s\", [\"%s\"], [/* %u vars */]) = 0\n",
184		       leader, av[0], av[0], arglen(environ));
185
186		get_sigsetsize();
187		static char buf[sizeof(sigsetsize) * 3];
188		sprintf(buf, "%u", sigsetsize);
189
190		char *argv[] = { av[0], buf, (char *) "0", NULL };
191		printf("%-5d execve(\"%s\", [\"%s\", \"%s\", \"%s\"]"
192		       ", [/* %u vars */]) = 0\n",
193		       leader, argv[0], argv[0], argv[1], argv[2],
194		       arglen(environ));
195		execve(argv[0], argv, environ);
196		perror_msg_and_fail("execve");
197	}
198
199	sigsetsize = atoi(av[1]);
200	action = atoi(av[2]);
201
202	if (action >= NUMBER_OF_ACTIONS * NUMBER_OF_ITERATIONS) {
203		printf("%-5d +++ exited with 0 +++\n", leader);
204		return 0;
205	}
206
207	if (pipe(fds))
208		perror_msg_and_fail("pipe");
209
210	pthread_t t;
211	errno = pthread_create(&t, NULL, thread, av);
212	if (errno)
213		perror_msg_and_fail("pthread_create");
214
215	struct timespec ts = { .tv_sec = 123 };
216	sigset_t mask;
217	sigemptyset(&mask);
218
219	static char leader_str[sizeof(leader) * 3];
220	int leader_str_len =
221		snprintf(leader_str, sizeof(leader_str), "%-5d", leader);
222
223	switch (action % NUMBER_OF_ACTIONS) {
224		case ACTION_exit:
225			printf("%s exit(42)%*s= ?\n", leader_str,
226			       (int) sizeof(leader_str) - leader_str_len, " ");
227			close(fds[1]);
228			(void) syscall(__NR_exit, 42);
229			break;
230		case ACTION_rt_sigsuspend:
231			printf("%s rt_sigsuspend([], %u <unfinished ...>\n",
232			       leader_str, sigsetsize);
233			close(fds[1]);
234			(void) k_sigsuspend(&mask);
235			break;
236		case ACTION_nanosleep:
237			printf("%s nanosleep({tv_sec=%u, tv_nsec=0}"
238			       ",  <unfinished ...>\n",
239			       leader_str, (unsigned int) ts.tv_sec);
240			close(fds[1]);
241			(void) nanosleep(&ts, 0);
242			break;
243	}
244
245	return 1;
246}
247