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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Simple memory eater. Runs as a daemon. Prints the child PID to
* std so you can easily kill it later.
* Usage: memeater <size in MB>
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
int main(int argc, char *argv[])
{
pid_t pid;
int fd;
int numMb = argc > 1 ? atoi(argv[1]) : 1;
if (argc < 2) {
printf("Usage: memeater <num MB to allocate>\n");
exit(1);
}
switch (fork()) {
case -1:
perror(argv[0]);
exit(1);
break;
case 0: /* child */
chdir("/");
umask(0);
setpgrp();
setsid();
/* fork again to fully detach from controlling terminal. */
switch (pid = fork()) {
case -1:
perror("failed to fork");
break;
case 0: /* second child */
/* redirect to /dev/null */
close(0);
open("/dev/null", 0);
for (fd = 3; fd < 256; fd++) {
close(fd);
}
printf("Allocating %d MB\n", numMb);
fflush(stdout);
/* allocate memory and fill it */
while (numMb > 0) {
// Allocate 500MB at a time at most
int mbToAllocate = numMb > 500 ? 500 : numMb;
int bytesToAllocate = mbToAllocate * 1024 * 1024;
char *p = malloc(bytesToAllocate);
if (p == NULL) {
printf("Failed to allocate memory\n");
exit(1);
}
for (int j = 0; j < bytesToAllocate; j++) {
p[j] = j & 0xFF;
}
printf("Allocated %d MB %p\n", mbToAllocate, p);
fflush(stdout);
numMb -= mbToAllocate;
}
close(1);
if (open("/dev/null", O_WRONLY) < 0) {
perror("/dev/null");
exit(1);
}
close(2);
dup(1);
/* Sit around doing nothing */
while (1) {
usleep(1000000);
}
default:
/* so caller can easily kill it later. */
printf("%d\n", pid);
exit(0);
break;
}
break;
default:
exit(0);
break;
}
return 0;
}
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