1 /*
2 * This file and its contents are supplied under the terms of the
3 * Common Development and Distribution License ("CDDL"), version 1.0.
4 * You may only use this file in accordance with the terms of version
5 * 1.0 of the CDDL.
6 *
7 * A full copy of the text of the CDDL should have accompanied this
8 * source. A copy of the CDDL is also available via the Internet at
9 * http://www.illumos.org/license/CDDL.
10 */
11
12 /*
13 * Copyright (c) 2016 by Delphix. All rights reserved.
14 */
15
16 /*
17 * Steal memory from the kernel, forcing the ARC to decrease in size, and hold
18 * it until the process receives a signal.
19 */
20
21 #include <stdio.h>
22 #include <sys/types.h>
23 #include <sys/shm.h>
24 #include <strings.h>
25 #include <stdlib.h>
26 #include <unistd.h>
27 #include <errno.h>
28
29 static void
usage(char * progname)30 usage(char *progname)
31 {
32 (void) fprintf(stderr, "Usage: %s -f <bytes>\n", progname);
33 exit(1);
34 }
35
36 static void
fail(char * err,int rval)37 fail(char *err, int rval)
38 {
39 perror(err);
40 exit(rval);
41 }
42
43 static void
daemonize(void)44 daemonize(void)
45 {
46 pid_t pid;
47
48 if ((pid = fork()) < 0) {
49 fail("fork", 1);
50 } else if (pid != 0) {
51 (void) fprintf(stdout, "%ld\n", pid);
52 exit(0);
53 }
54
55 (void) setsid();
56 (void) close(0);
57 (void) close(1);
58 (void) close(2);
59 }
60
61 int
main(int argc,char * argv[])62 main(int argc, char *argv[])
63 {
64 int c;
65 boolean_t fflag = B_FALSE;
66 char *prog = argv[0];
67 long long size;
68 char *stroll_leftovers;
69 int shm_id;
70 void *shm_attached;
71
72 while ((c = getopt(argc, argv, "f")) != -1) {
73 switch (c) {
74 /* Run in the foreground */
75 case 'f':
76 fflag = B_TRUE;
77 break;
78 default:
79 usage(prog);
80 }
81 }
82
83 argc -= optind;
84 argv += optind;
85
86 if (argc != 1)
87 usage(prog);
88 size = strtoll(argv[0], &stroll_leftovers, 10);
89 if (size <= 0)
90 fail("invalid size in bytes", 1);
91
92 if ((shm_id = shmget(IPC_PRIVATE, size, IPC_CREAT|IPC_EXCL)) == -1)
93 fail("shmget", 1);
94 if ((shm_attached = shmat(shm_id, NULL, SHM_SHARE_MMU)) == (void *)-1)
95 fail("shmat", 1);
96
97 if (fflag == B_FALSE)
98 daemonize();
99 (void) pause();
100
101 /* NOTREACHED */
102 return (0);
103 }
104