/*
* Copyright (C) 2014 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.
*/
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <logwrap/logwrap.h>
#include <sys/stat.h>
#include <sys/statvfs.h>
#include <utils/Log.h>
#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
#define MAX_IO_WRITE_CHUNK_SIZE 0x100000
#ifndef min
#define min(a,b) ((a) < (b) ? (a) : (b))
#endif
typedef unsigned long u64;
static void usage(const char * const progname) {
fprintf(stderr,
"Usage: %s [-s <seed>] -h <hole size in bytes> -t <total hole size in bytes> "
"path\n",
progname);
}
static u64 get_free_space(const char * const path) {
struct statvfs s;
if (statvfs(path, &s) < 0) {
fprintf(stderr, "\nerrno: %d. Failed to get free disk space on %s\n",
errno, path);
return 0;
} else {
return (u64)s.f_bsize * (u64)s.f_bfree;
}
}
static u64 get_random_num(const u64 start, const u64 end) {
if (end - start <= 0)
return start;
assert(RAND_MAX >= 0x7FFFFFFF);
if ((end - start) > 0x7FFFFFFF)
return start + (((u64)random() << 31) | (u64)random()) % (end - start);
return start + (random() % (end - start));
}
static char get_random_char() {
return 'A' + random() % ('Z' - 'A');
}
static bool create_unique_file(const char * const dir_path, const u64 size,
const u64 id, char * const base,
const u64 base_length) {
u64 length = 0;
int fd;
char file_path[FILENAME_MAX];
bool ret = true;
base[random() % min(base_length, size)] = get_random_char();
sprintf(file_path, "%s/file_%lu", dir_path, id);
fd = open(file_path, O_WRONLY | O_CREAT | O_SYNC, 0777);
if (fd < 0) {
// We suppress ENOSPC erros as that is common as we approach the
// last few MBs of the fs as we don't account for the size of the newly
// added meta data after the initial free space computation.
if (errno != 28) {
fprintf(stderr, "\nerrno: %d. Failed to create %s\n", errno, file_path);
}
return false;
}
while (length + base_length < size) {
if (write(fd, base, base_length) < 0) {
if (errno != 28) {
fprintf(stderr, "\nerrno: %d. Failed to write %lu bytes to %s\n",
errno, base_length, file_path);
}
ret = false;
goto done;
}
length += base_length;
}
if (write(fd, base, size - length) < 0) {
if (errno != 28) {
fprintf(stderr, "\nerrno: %d. Failed to write last %lu bytes to %s\n",
errno, size - length, file_path);
}
ret = false;
goto done;
}
done:
if (close(fd) < 0) {
fprintf(stderr, "\nFailed to close %s\n", file_path);
ret = false;
}
return ret;
}
static bool create_unique_dir(char *dir, const char * const root_path) {
char random_string[15];
int i;
for (i = 0; i < 14; ++i) {
random_string[i] = get_random_char();
}
random_string[14] = '\0';
sprintf(dir, "%s/%s", root_path, random_string);
if (mkdir(dir, 0777) < 0) {
fprintf(stderr, "\nerrno: %d. Failed to create %s\n", errno, dir);
return false;
}
return true;
}
static bool puncture_fs (const char * const path, const u64 total_size,
const u64 hole_size, const u64 total_hole_size) {
u64 increments = (hole_size * total_size) / total_hole_size;
u64 hole_max;
u64 starting_max = 0;
u64 ending_max = increments;
char stay_dir[FILENAME_MAX], delete_dir[FILENAME_MAX];
char *rm_bin_argv[] = { "/system/bin/rm", "-rf", ""};
u64 file_id = 1;
char *base_file_data;
u64 i = 0;
if (!create_unique_dir(stay_dir, path) ||
!create_unique_dir(delete_dir, path)) {
return false;
}
base_file_data = (char*) malloc(MAX_IO_WRITE_CHUNK_SIZE);
for (i = 0; i < MAX_IO_WRITE_CHUNK_SIZE; ++i) {
base_file_data[i] = get_random_char();
}
fprintf(stderr, "\n");
while (ending_max <= total_size) {
fprintf(stderr, "\rSTAGE 1/2: %d%% Complete",
(int) (100.0 * starting_max / total_size));
hole_max = get_random_num(starting_max, ending_max);
do {
hole_max = get_random_num(starting_max, ending_max);
} while (hole_max == starting_max);
create_unique_file(stay_dir,
hole_max - starting_max,
file_id++,
base_file_data,
MAX_IO_WRITE_CHUNK_SIZE);
create_unique_file(delete_dir,
hole_size,
file_id++,
base_file_data,
MAX_IO_WRITE_CHUNK_SIZE);
starting_max = hole_max + hole_size;
ending_max += increments;
}
create_unique_file(stay_dir,
(ending_max - increments - starting_max),
file_id++,
base_file_data,
MAX_IO_WRITE_CHUNK_SIZE);
fprintf(stderr, "\rSTAGE 1/2: 100%% Complete\n");
fprintf(stderr, "\rSTAGE 2/2: 0%% Complete");
free(base_file_data);
rm_bin_argv[2] = delete_dir;
if (android_fork_execvp_ext(ARRAY_SIZE(rm_bin_argv), rm_bin_argv,
NULL, 1, LOG_KLOG, 0, NULL, NULL, 0) < 0) {
fprintf(stderr, "\nFailed to delete %s\n", rm_bin_argv[2]);
return false;
}
fprintf(stderr, "\rSTAGE 2/2: 100%% Complete\n");
return true;
}
int main (const int argc, char ** const argv) {
int opt;
int mandatory_opt;
char *path = NULL;
int seed = time(NULL);
u64 total_size = 0;
u64 hole_size = 0;
u64 total_hole_size = 0;
mandatory_opt = 2;
while ((opt = getopt(argc, argv, "s:h:t:")) != -1) {
switch(opt) {
case 's':
seed = atoi(optarg);
break;
case 'h':
hole_size = atoll(optarg);
mandatory_opt--;
break;
case 't':
total_hole_size = atoll(optarg);
mandatory_opt--;
break;
default:
usage(argv[0]);
exit(EXIT_FAILURE);
}
}
if (mandatory_opt) {
usage(argv[0]);
exit(EXIT_FAILURE);
}
if (optind >= argc) {
fprintf(stderr, "\nExpected path name after options.\n");
usage(argv[0]);
exit(EXIT_FAILURE);
}
path = argv[optind++];
if (optind < argc) {
fprintf(stderr, "\nUnexpected argument: %s\n", argv[optind]);
usage(argv[0]);
exit(EXIT_FAILURE);
}
srandom(seed);
fprintf(stderr, "\nRandom seed is: %d\n", seed);
total_size = get_free_space(path);
if (!total_size) {
exit(EXIT_FAILURE);
}
if (total_size < total_hole_size || total_hole_size < hole_size) {
fprintf(stderr, "\nInvalid sizes: total available size should be "
"larger than total hole size which is larger than "
"hole size\n");
exit(EXIT_FAILURE);
}
if (!puncture_fs(path, total_size, hole_size, total_hole_size)) {
exit(EXIT_FAILURE);
}
return 0;
}