1 /* $OpenBSD: t_fork.c,v 1.5 2021/12/13 16:56:48 deraadt Exp $ */
2 /* $NetBSD: t_fork.c,v 1.4 2019/04/06 15:41:54 kamil Exp $ */
3
4 /*-
5 * Copyright (c) 2018, 2019 The NetBSD Foundation, Inc.
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 *
17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
28 */
29 #include "macros.h"
30
31 #include <sys/types.h>
32 #include <sys/signal.h>
33 #ifdef __OpenBSD__
34 #include <sys/proc.h>
35 #endif
36 #include <sys/sysctl.h>
37 #include <sys/wait.h>
38 #include <sched.h>
39 #include <signal.h>
40 #include <stdbool.h>
41 #include <stdlib.h>
42 #include <unistd.h>
43 #include <err.h>
44 #include <errno.h>
45
46 #include "atf-c.h"
47
48 #ifdef VFORK
49 #define FORK vfork
50 #else
51 #define FORK fork
52 #endif
53
54 /*
55 * A child process cannot call atf functions and expect them to magically
56 * work like in the parent.
57 * The printf(3) messaging from a child will not work out of the box as well
58 * without estabilishing a communication protocol with its parent. To not
59 * overcomplicate the tests - do not log from a child and use err(3)/errx(3)
60 * wrapped with ASSERT_EQ()/ASSERT_NEQ() as that is guaranteed to work.
61 */
62 #define ASSERT_EQ(x, y) \
63 do { \
64 uintmax_t vx = (x); \
65 uintmax_t vy = (y); \
66 int ret = vx == vy; \
67 if (!ret) \
68 errx(EXIT_FAILURE, "%s:%d %s(): Assertion failed for: " \
69 "%s(%ju) == %s(%ju)", __FILE__, __LINE__, __func__, \
70 #x, vx, #y, vy); \
71 } while (/*CONSTCOND*/0)
72
73 #define ASSERT_NEQ(x, y) \
74 do { \
75 uintmax_t vx = (x); \
76 uintmax_t vy = (y); \
77 int ret = vx != vy; \
78 if (!ret) \
79 errx(EXIT_FAILURE, "%s:%d %s(): Assertion failed for: " \
80 "%s(%ju) != %s(%ju)", __FILE__, __LINE__, __func__, \
81 #x, vx, #y, vy); \
82 } while (/*CONSTCOND*/0)
83
84 static pid_t
await_stopped_child(pid_t process)85 await_stopped_child(pid_t process)
86 {
87 struct kinfo_proc2 *p = NULL;
88 size_t i, len;
89 pid_t child = -1;
90
91 int name[] = {
92 [0] = CTL_KERN,
93 [1] = KERN_PROC2,
94 [2] = KERN_PROC_ALL,
95 [3] = 0,
96 [4] = sizeof(struct kinfo_proc2),
97 [5] = 0
98 };
99
100 const size_t namelen = __arraycount(name);
101
102 /* Await the process becoming a zombie */
103 while(1) {
104 name[5] = 0;
105
106 ASSERT_EQ(sysctl(name, namelen, 0, &len, NULL, 0), 0);
107
108 ASSERT_EQ(reallocarr(&p, len, sizeof(struct kinfo_proc2)), 0);
109
110 name[5] = len;
111
112 ASSERT_EQ(sysctl(name, namelen, p, &len, NULL, 0), 0);
113
114 for (i = 0; i < len/sizeof(struct kinfo_proc2); i++) {
115 if (p[i].p_pid == getpid())
116 continue;
117 if (p[i].p_ppid != process)
118 continue;
119 if (p[i].p_stat != LSSTOP)
120 continue;
121 child = p[i].p_pid;
122 break;
123 }
124
125 if (child != -1)
126 break;
127
128 ASSERT_EQ(usleep(1000), 0);
129 }
130
131 /* Free the buffer */
132 ASSERT_EQ(reallocarr(&p, 0, sizeof(struct kinfo_proc2)), 0);
133
134 return child;
135 }
136
137 static void
raise_raw(int sig)138 raise_raw(int sig)
139 {
140 int rv, status;
141 pid_t child, parent, watcher, wpid;
142 int expect_core = (sig == SIGABRT) ? 1 : 0;
143
144 /*
145 * Spawn a dedicated thread to watch for a stopped child and emit
146 * the SIGKILL signal to it.
147 *
148 * This is required in vfork(2)ing parent and optional in fork(2).
149 *
150 * vfork(2) might clobber watcher, this means that it's safer and
151 * simpler to reparent this process to initproc and forget about it.
152 */
153 if (sig == SIGSTOP
154 #ifndef VFORK
155 || (sig == SIGTSTP || sig == SIGTTIN || sig == SIGTTOU)
156 #endif
157 ) {
158
159 parent = getpid();
160
161 watcher = fork();
162 ATF_REQUIRE(watcher != 1);
163 if (watcher == 0) {
164 /* Double fork(2) trick to reparent to initproc */
165 watcher = fork();
166 ASSERT_NEQ(watcher, -1);
167 if (watcher != 0)
168 _exit(0);
169
170 child = await_stopped_child(parent);
171
172 errno = 0;
173 rv = kill(child, SIGKILL);
174 ASSERT_EQ(rv, 0);
175 ASSERT_EQ(errno, 0);
176
177 /* This exit value will be collected by initproc */
178 _exit(0);
179 }
180
181 wpid = waitpid(watcher, &status, 0);
182
183 ATF_REQUIRE_EQ(wpid, watcher);
184
185 ATF_REQUIRE(WIFEXITED(status));
186 ATF_REQUIRE(!WIFCONTINUED(status));
187 ATF_REQUIRE(!WIFSIGNALED(status));
188 ATF_REQUIRE(!WIFSTOPPED(status));
189 ATF_REQUIRE_EQ(WEXITSTATUS(status), 0);
190 }
191
192 child = FORK();
193 ATF_REQUIRE(child != 1);
194 if (child == 0) {
195 rv = raise(sig);
196 ASSERT_EQ(rv, 0);
197 _exit(0);
198 }
199 wpid = waitpid(child, &status, 0);
200
201 ATF_REQUIRE_EQ(wpid, child);
202
203 switch (sig) {
204 case SIGKILL:
205 case SIGABRT:
206 case SIGHUP:
207 ATF_REQUIRE(!WIFEXITED(status));
208 ATF_REQUIRE(!WIFCONTINUED(status));
209 ATF_REQUIRE(WIFSIGNALED(status));
210 ATF_REQUIRE(!WIFSTOPPED(status));
211 ATF_REQUIRE_EQ(WTERMSIG(status), sig);
212 ATF_REQUIRE_EQ(!!WCOREDUMP(status), expect_core);
213 break;
214 #ifdef VFORK
215 case SIGTSTP:
216 case SIGTTIN:
217 case SIGTTOU:
218 #endif
219 case SIGCONT:
220 ATF_REQUIRE(WIFEXITED(status));
221 ATF_REQUIRE(!WIFCONTINUED(status));
222 ATF_REQUIRE(!WIFSIGNALED(status));
223 ATF_REQUIRE(!WIFSTOPPED(status));
224 ATF_REQUIRE_EQ(WEXITSTATUS(status), 0);
225 break;
226 #ifndef VFORK
227 case SIGTSTP:
228 case SIGTTIN:
229 case SIGTTOU:
230 #endif
231 case SIGSTOP:
232 ATF_REQUIRE(!WIFEXITED(status));
233 ATF_REQUIRE(!WIFCONTINUED(status));
234 ATF_REQUIRE(WIFSIGNALED(status));
235 ATF_REQUIRE(!WIFSTOPPED(status));
236 ATF_REQUIRE_EQ(WTERMSIG(status), SIGKILL);
237 ATF_REQUIRE_EQ(!!WCOREDUMP(status), 0);
238 }
239 }
240
241 #define RAISE(test, sig) \
242 ATF_TC(test); \
243 ATF_TC_HEAD(test, tc) \
244 { \
245 \
246 atf_tc_set_md_var(tc, "descr", \
247 "raise " #sig " in a child"); \
248 } \
249 \
250 ATF_TC_BODY(test, tc) \
251 { \
252 \
253 raise_raw(sig); \
254 }
255
RAISE(raise1,SIGKILL)256 RAISE(raise1, SIGKILL) /* non-maskable */
257 RAISE(raise2, SIGSTOP) /* non-maskable */
258 RAISE(raise3, SIGTSTP) /* ignored in vfork(2) */
259 RAISE(raise4, SIGTTIN) /* ignored in vfork(2) */
260 RAISE(raise5, SIGTTOU) /* ignored in vfork(2) */
261 RAISE(raise6, SIGABRT) /* regular abort trap */
262 RAISE(raise7, SIGHUP) /* hangup */
263 RAISE(raise8, SIGCONT) /* continued? */
264
265 /// ----------------------------------------------------------------------------
266
267 static int
268 clone_func(void *arg __unused)
269 {
270
271 return 0;
272 }
273
274 static void
nested_raw(const char * fn,volatile int flags)275 nested_raw(const char *fn, volatile int flags)
276 {
277 int status;
278 pid_t child, child2, wpid;
279 const size_t stack_size = 1024 * 1024;
280 void *stack, *stack_base;
281
282 stack = malloc(stack_size);
283 ATF_REQUIRE(stack != NULL);
284
285 #ifdef __MACHINE_STACK_GROWS_UP
286 stack_base = stack;
287 #else
288 stack_base = (char *)stack + stack_size;
289 #endif
290
291 flags |= SIGCHLD;
292
293 child = FORK();
294 ATF_REQUIRE(child != 1);
295 if (child == 0) {
296 if (strcmp(fn, "fork") == 0)
297 child2 = fork();
298 else if (strcmp(fn, "vfork") == 0)
299 child2 = vfork();
300 #ifndef __OpenBSD__
301 else if (strcmp(fn, "clone") == 0)
302 child2 = __clone(clone_func, stack_base, flags, NULL);
303 #endif
304 else
305 __unreachable();
306
307 ASSERT_NEQ(child2, -1);
308
309 if ((strcmp(fn, "fork") == 0) || (strcmp(fn, "vfork") == 0)) {
310 if (child2 == 0)
311 _exit(0);
312 }
313
314 wpid = waitpid(child2, &status, 0);
315 ASSERT_EQ(child2, wpid);
316 ASSERT_EQ(!!WIFEXITED(status), true);
317 ASSERT_EQ(!!WIFCONTINUED(status), false);
318 ASSERT_EQ(!!WIFSIGNALED(status), false);
319 ASSERT_EQ(!!WIFSTOPPED(status), false);
320 ASSERT_EQ(WEXITSTATUS(status), 0);
321
322 _exit(0);
323 }
324 wpid = waitpid(child, &status, 0);
325
326 ATF_REQUIRE_EQ(wpid, child);
327 ATF_REQUIRE_EQ(!!WIFEXITED(status), true);
328 ATF_REQUIRE_EQ(!!WIFCONTINUED(status), false);
329 ATF_REQUIRE_EQ(!!WIFSIGNALED(status), false);
330 ATF_REQUIRE_EQ(!!WIFSTOPPED(status), false);
331 ATF_REQUIRE_EQ(WEXITSTATUS(status), 0);
332 }
333
334 #define NESTED(test, fn, flags) \
335 ATF_TC(test); \
336 ATF_TC_HEAD(test, tc) \
337 { \
338 \
339 atf_tc_set_md_var(tc, "descr", \
340 "Test nested " #fn " in a child"); \
341 } \
342 \
343 ATF_TC_BODY(test, tc) \
344 { \
345 \
346 nested_raw(#fn, flags); \
347 }
348
349 NESTED(nested_fork, fork, 0)
350 NESTED(nested_vfork, vfork, 0)
351 #ifndef __OpenBSD__
352 NESTED(nested_clone, clone, 0)
NESTED(nested_clone_vm,clone,CLONE_VM)353 NESTED(nested_clone_vm, clone, CLONE_VM)
354 NESTED(nested_clone_fs, clone, CLONE_FS)
355 NESTED(nested_clone_files, clone, CLONE_FILES)
356 //NESTED(nested_clone_sighand, clone, CLONE_SIGHAND) // XXX
357 NESTED(nested_clone_vfork, clone, CLONE_VFORK)
358 #endif
359
360 ATF_TP_ADD_TCS(tp)
361 {
362 ATF_TP_ADD_TC(tp, raise1);
363 ATF_TP_ADD_TC(tp, raise2);
364 ATF_TP_ADD_TC(tp, raise3);
365 ATF_TP_ADD_TC(tp, raise4);
366 ATF_TP_ADD_TC(tp, raise5);
367 ATF_TP_ADD_TC(tp, raise6);
368 ATF_TP_ADD_TC(tp, raise7);
369 ATF_TP_ADD_TC(tp, raise8);
370
371 ATF_TP_ADD_TC(tp, nested_fork);
372 ATF_TP_ADD_TC(tp, nested_vfork);
373 #ifndef __OpenBSD__
374 ATF_TP_ADD_TC(tp, nested_clone);
375 ATF_TP_ADD_TC(tp, nested_clone_vm);
376 ATF_TP_ADD_TC(tp, nested_clone_fs);
377 ATF_TP_ADD_TC(tp, nested_clone_files);
378 // ATF_TP_ADD_TC(tp, nested_clone_sighand); // XXX
379 ATF_TP_ADD_TC(tp, nested_clone_vfork);
380 #endif
381
382 return atf_no_error();
383 }
384