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 cpu eater busy loop. Runs as a daemon. prints the child PID to 17 * std so you can easily kill it later. 18 */ 19 20 #include <stdio.h> 21 #include <unistd.h> 22 #include <stdlib.h> 23 #include <fcntl.h> 24 #include <sys/types.h> 25 #include <sys/stat.h> 26 27 28 int main(int argc, char *argv[]) 29 { 30 pid_t pid; 31 int life_universe_and_everything; 32 int fd; 33 34 switch(fork()) { 35 case -1: 36 perror(argv[0]); 37 exit(1); 38 break; 39 case 0: /* child */ 40 chdir("/"); 41 umask(0); 42 setpgrp(); 43 setsid(); 44 /* fork again to fully detach from controlling terminal. */ 45 switch(pid = fork()) { 46 case -1: 47 break; 48 case 0: /* second child */ 49 /* redirect to /dev/null */ 50 close(0); 51 open("/dev/null", 0); 52 close(1); 53 if(open("/dev/null", O_WRONLY) < 0) { 54 perror("/dev/null"); 55 exit(1); 56 } 57 fflush(stdout); 58 close(2); 59 dup(1); 60 for (fd = 3; fd < 256; fd++) { 61 close(fd); 62 } 63 /* busy looper */ 64 while (1) { 65 life_universe_and_everything = 42 * 2; 66 } 67 default: 68 /* so caller can easily kill it later. */ 69 printf("%d\n", pid); 70 exit(0); 71 break; 72 } 73 break; 74 default: 75 exit(0); 76 break; 77 } 78 return 0; 79 } 80 81 82 /* vim:ts=4:sw=4:softtabstop=4:smarttab:expandtab */ 83 84
