xref: /freebsd/tests/sys/kern/pdrfork.c (revision d1e6057fa47e842c63461b64b29ac5d3e9fdad76)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2026 ConnectWise
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/types.h>
29 #include <sys/user.h>
30 #include <sys/procdesc.h>
31 #include <sys/wait.h>
32 
33 #include <atf-c.h>
34 #include <stdio.h>
35 #include <string.h>
36 #include <unistd.h>
37 
basic_usage(int rfflags)38 static void basic_usage(int rfflags) {
39 	int pd = -1;
40 	pid_t pid, pd_pid, waited_pid;
41 	int r, status;
42 
43 	pid = pdrfork(&pd, 0, rfflags);
44 	ATF_REQUIRE_MSG(pid >= 0, "rfork failed with %s", strerror(errno));
45 	if (pid == 0) {
46 		/* In child */
47 		_exit(0);
48 	}
49 	ATF_REQUIRE_MSG(pd >= 0, "rfork did not return a process descriptor");
50 	r = pdgetpid(pd, &pd_pid);
51 	ATF_CHECK_EQ_MSG(r, 0, "pdgetpid failed: %s", strerror(errno));
52 
53 	/* We should be able to collect the child's status */
54 	waited_pid = waitpid(pid, &status, WEXITED | WNOWAIT);
55 	ATF_CHECK_EQ(waited_pid, pid);
56 
57 	/* But after closing the process descriptor, we won't */
58 	close(pd);
59 	waited_pid = waitpid(pid, &status, WEXITED | WNOHANG);
60 	ATF_CHECK_EQ(-1, waited_pid);
61 	ATF_CHECK_EQ(ECHILD, errno);
62 }
63 
64 /* pdrfork does not return a process descriptor to the child */
65 ATF_TC_WITHOUT_HEAD(child_gets_no_pidfd);
ATF_TC_BODY(child_gets_no_pidfd,tc)66 ATF_TC_BODY(child_gets_no_pidfd, tc)
67 {
68 	int pd = -1;
69 	pid_t pid, pd_pid, waited_pid;
70 	int r, status;
71 
72 	pid = pdrfork(&pd, 0, RFPROC | RFPROCDESC);
73 	ATF_REQUIRE_MSG(pid >= 0, "rfork failed with %s", strerror(errno));
74 	if (pid == 0) {
75 		/*
76 		 * In child.  We can't do very much here before we exec, so
77 		 * just use our exit status to report success.
78 		 */
79 		_exit(pd == -1);
80 	}
81 	ATF_REQUIRE_MSG(pd >= 0, "rfork did not return a process descriptor");
82 	r = pdgetpid(pd, &pd_pid);
83 	ATF_CHECK_EQ_MSG(r, 0, "pdgetpid failed: %s", strerror(errno));
84 
85 	waited_pid = waitpid(pid, &status, WEXITED | WNOWAIT);
86 	ATF_CHECK_EQ(waited_pid, pid);
87 	ATF_REQUIRE(WIFEXITED(status) && (WEXITSTATUS(status) == true));
88 
89 	close(pd);
90 }
91 
92 /* If the pidfd argument is invalid, the error should be handled gracefully */
93 ATF_TC_WITHOUT_HEAD(efault);
ATF_TC_BODY(efault,tc)94 ATF_TC_BODY(efault, tc)
95 {
96 	ATF_REQUIRE_ERRNO(EFAULT, pdrfork((int*)-1, 0, RFPROC | RFPROCDESC) < 0);
97 }
98 
99 /* Invalid combinations of flags should return EINVAL */
100 ATF_TC_WITHOUT_HEAD(einval);
ATF_TC_BODY(einval,tc)101 ATF_TC_BODY(einval, tc)
102 {
103 	int pd = -1;
104 
105 	ATF_CHECK_ERRNO(EINVAL, pdrfork(&pd, -1, RFSPAWN) < 0);
106 	ATF_CHECK_ERRNO(EINVAL, pdrfork(&pd, 0, -1) < 0);
107 	ATF_CHECK_ERRNO(EINVAL, pdrfork(&pd, 0, RFSPAWN | RFNOWAIT) < 0);
108 	ATF_CHECK_ERRNO(EINVAL, pdrfork(&pd, 0, RFPROC | RFFDG| RFCFDG) < 0);
109 	ATF_CHECK_ERRNO(EINVAL, pdrfork(&pd, 0, RFPROCDESC) < 0);
110 }
111 
112 /*
113  * Without RFSPAWN, RFPROC, or RFPROCDESC, an existing process may be modified
114  */
115 ATF_TC_WITHOUT_HEAD(modify_child);
ATF_TC_BODY(modify_child,tc)116 ATF_TC_BODY(modify_child, tc)
117 {
118 	int fdp = -1;
119 	pid_t pid1, pid2;
120 
121 	pid1 = pdfork(&fdp, 0);
122 	if (pid1 == 0)
123 		_exit(0);
124 	ATF_REQUIRE_MSG(pid1 >= 0, "pdfork failed: %s", strerror(errno));
125 	ATF_REQUIRE_MSG(fdp >= 0, "pdfork didn't return a process descriptor");
126 
127 	pid2 = pdrfork(&fdp, 0, RFNOWAIT);
128 	ATF_REQUIRE_MSG(pid2 >= 0, "pdrfork failed: %s", strerror(errno));
129 	ATF_CHECK_EQ_MSG(pid2, 0,
130 	    "pdrfork created a process even though we told it not to");
131 
132 	close(fdp);
133 }
134 
135 /*
136  * Basic usage with RFPROC.  No process descriptor will be created.
137  * I'm not sure why you would use pdrfork in this case instead of plain rfork
138  */
139 ATF_TC_WITHOUT_HEAD(rfproc);
ATF_TC_BODY(rfproc,tc)140 ATF_TC_BODY(rfproc, tc)
141 {
142 	int pd = -1;
143 	pid_t pid;
144 
145 	pid = pdrfork(&pd, 0, RFPROC);
146 	ATF_REQUIRE_MSG(pid > 0, "rfork failed with %s", strerror(errno));
147 	if (pid == 0)
148 		_exit(0);
149 
150 	ATF_REQUIRE_EQ_MSG(pd, -1,
151 	    "rfork(RFPROC) returned a process descriptor");
152 }
153 
154 /* basic usage with RFPROCDESC */
155 ATF_TC_WITHOUT_HEAD(rfprocdesc);
ATF_TC_BODY(rfprocdesc,tc)156 ATF_TC_BODY(rfprocdesc, tc)
157 {
158 	basic_usage(RFPROC | RFPROCDESC);
159 }
160 
161 /* basic usage with RFSPAWN */
162 /*
163  * Skip on i386 and x86_64 because RFSPAWN cannot be used from C code on those
164  * architectures.  See lib/libc/gen/posix_spawn.c for details.
165  */
166 #if !(defined(__i386__)) && !(defined(__amd64__))
167 ATF_TC_WITHOUT_HEAD(rfspawn);
ATF_TC_BODY(rfspawn,tc)168 ATF_TC_BODY(rfspawn, tc)
169 {
170 	basic_usage(RFSPAWN);
171 }
172 #endif
173 
ATF_TP_ADD_TCS(tp)174 ATF_TP_ADD_TCS(tp)
175 {
176 	ATF_TP_ADD_TC(tp, child_gets_no_pidfd);
177 	ATF_TP_ADD_TC(tp, efault);
178 	ATF_TP_ADD_TC(tp, einval);
179 	ATF_TP_ADD_TC(tp, modify_child);
180 	ATF_TP_ADD_TC(tp, rfproc);
181 	ATF_TP_ADD_TC(tp, rfprocdesc);
182 #if !(defined(__i386__)) && !(defined(__amd64__))
183 	ATF_TP_ADD_TC(tp, rfspawn);
184 #endif
185 
186 	return (atf_no_error());
187 }
188