1 /*
2 * Copyright (c) 2015 Dmitry V. Levin <ldv@altlinux.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #ifdef HAVE_CONFIG_H
29 # include "config.h"
30 #endif
31
32 #include <fcntl.h>
33 #include <stdio.h>
34 #include <string.h>
35 #include <unistd.h>
36 #include <sys/wait.h>
37
38 static inline int
logit(const char * const str)39 logit(const char *const str)
40 {
41 return pwrite(-1, str, strlen(str), 0) >= 0;
42 }
43
main(int ac,char ** av,char ** ep)44 int main(int ac, char **av, char **ep)
45 {
46 if (ac < 1)
47 return 1;
48 if (ac > 1) {
49 if (read(0, &ac, sizeof(int)))
50 return 2;
51 return logit(av[1]);
52 }
53
54 logit("start");
55
56 int fds[2];
57 (void) close(0);
58 if (pipe(fds)) {
59 perror("pipe");
60 return 77;
61 }
62 if (fcntl(fds[1], F_SETFD, FD_CLOEXEC)) {
63 perror("fcntl");
64 return 77;
65 }
66
67 char *const args[] = { av[0], (char *) "exec", NULL };
68 pid_t pid = vfork();
69
70 if (pid < 0) {
71 perror("vfork");
72 return 77;
73 }
74
75 if (!pid) {
76 if (logit("child") || execve(args[0], args, args + 1))
77 _exit(2);
78 }
79
80 close(0);
81
82 logit("parent");
83 close(fds[1]);
84
85 int status;
86 if (wait(&status) != pid) {
87 perror("wait");
88 return 77;
89 }
90 if (status) {
91 fprintf(stderr, "status = %d\n", status);
92 return 77;
93 }
94
95 logit("finish");
96
97 pid_t ppid = getpid();
98 close(-1);
99 printf("%-5d pwrite64(-1, \"start\", 5, 0) = -1 EBADF (%m)\n"
100 "%-5d pwrite64(-1, \"child\", 5, 0) = -1 EBADF (%m)\n"
101 "%-5d pwrite64(-1, \"parent\", 6, 0) = -1 EBADF (%m)\n"
102 "%-5d pwrite64(-1, \"exec\", 4, 0) = -1 EBADF (%m)\n"
103 "%-5d pwrite64(-1, \"finish\", 6, 0) = -1 EBADF (%m)\n",
104 ppid, pid, ppid, pid, ppid);
105 return 0;
106 }
107