Amith Yamasani | 783a914 | 2017-09-13 14:32:57 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2008 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | * |
| 16 | * Simple memory eater. Runs as a daemon. Prints the child PID to |
| 17 | * std so you can easily kill it later. |
| 18 | * Usage: memeater <size in MB> |
| 19 | */ |
| 20 | |
| 21 | #include <stdio.h> |
| 22 | #include <unistd.h> |
| 23 | #include <stdlib.h> |
| 24 | #include <fcntl.h> |
| 25 | #include <sys/types.h> |
| 26 | #include <sys/stat.h> |
| 27 | |
| 28 | int main(int argc, char *argv[]) |
| 29 | { |
| 30 | pid_t pid; |
| 31 | int fd; |
| 32 | int numMb = argc > 1 ? atoi(argv[1]) : 1; |
| 33 | |
| 34 | if (argc < 2) { |
| 35 | printf("Usage: memeater <num MB to allocate>\n"); |
| 36 | exit(1); |
| 37 | } |
| 38 | |
| 39 | switch (fork()) { |
| 40 | case -1: |
| 41 | perror(argv[0]); |
| 42 | exit(1); |
| 43 | break; |
| 44 | case 0: /* child */ |
| 45 | chdir("/"); |
| 46 | umask(0); |
| 47 | setpgrp(); |
| 48 | setsid(); |
| 49 | /* fork again to fully detach from controlling terminal. */ |
| 50 | switch (pid = fork()) { |
| 51 | case -1: |
| 52 | perror("failed to fork"); |
| 53 | break; |
| 54 | case 0: /* second child */ |
| 55 | /* redirect to /dev/null */ |
| 56 | close(0); |
| 57 | open("/dev/null", 0); |
| 58 | for (fd = 3; fd < 256; fd++) { |
| 59 | close(fd); |
| 60 | } |
| 61 | |
| 62 | printf("Allocating %d MB\n", numMb); |
| 63 | fflush(stdout); |
| 64 | /* allocate memory and fill it */ |
| 65 | while (numMb > 0) { |
| 66 | // Allocate 500MB at a time at most |
| 67 | int mbToAllocate = numMb > 500 ? 500 : numMb; |
| 68 | int bytesToAllocate = mbToAllocate * 1024 * 1024; |
| 69 | char *p = malloc(bytesToAllocate); |
| 70 | if (p == NULL) { |
| 71 | printf("Failed to allocate memory\n"); |
| 72 | exit(1); |
| 73 | } |
| 74 | for (int j = 0; j < bytesToAllocate; j++) { |
| 75 | p[j] = j & 0xFF; |
| 76 | } |
| 77 | printf("Allocated %d MB %p\n", mbToAllocate, p); |
| 78 | fflush(stdout); |
| 79 | numMb -= mbToAllocate; |
| 80 | } |
| 81 | |
| 82 | close(1); |
| 83 | if (open("/dev/null", O_WRONLY) < 0) { |
| 84 | perror("/dev/null"); |
| 85 | exit(1); |
| 86 | } |
| 87 | close(2); |
| 88 | dup(1); |
| 89 | |
| 90 | /* Sit around doing nothing */ |
| 91 | while (1) { |
| 92 | usleep(1000000); |
| 93 | } |
| 94 | default: |
| 95 | /* so caller can easily kill it later. */ |
| 96 | printf("%d\n", pid); |
| 97 | exit(0); |
| 98 | break; |
| 99 | } |
| 100 | break; |
| 101 | default: |
| 102 | exit(0); |
| 103 | break; |
| 104 | } |
| 105 | return 0; |
| 106 | } |
| 107 | |