ddnuke.c

   1 /*
   2  * released into the public domain
   3  * written by Mike Frysinger <vapier>
   4  */
   5
   6 #pragma GCC diagnostic warning "-Wall"
   7 #pragma GCC diagnostic warning "-Wextra"
   8
   9 #define _FILE_OFFSET_BITS 64
  10 #define _LARGEFILE_SOURCE
  11 #define _LARGEFILE64_SOURCE
  12 #define _GNU_SOURCE
  13
  14 #include <ctype.h>
  15 #include <err.h>
  16 #include <errno.h>
  17 #include <fcntl.h>
  18 #include <inttypes.h>
  19 #include <locale.h>
  20 #include <spawn.h>
  21 #include <stdbool.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <sysexits.h>
  26 #include <time.h>
  27 #include <unistd.h>
  28 #include <sys/ioctl.h>
  29 #include <sys/stat.h>
  30 #include <sys/types.h>
  31 #include <sys/wait.h>
  32 #include <linux/fs.h>
  33
  34 static unsigned long long mbps(struct timespec *stime, struct timespec *etime, off_t len)
  35 {
  36         uint64_t dtime;
  37         clock_gettime(CLOCK_MONOTONIC, etime);
  38         dtime = ((etime->tv_sec - stime->tv_sec) * 1000 * 1000 * 1000) +
  39                 (etime->tv_nsec - stime->tv_nsec);
  40         *stime = *etime;
  41         return 1000 * len / dtime;
  42 }
  43
  44 static off_t get_blk_size(int fd)
  45 {
  46         uint64_t size;
  47         if (ioctl(fd, BLKGETSIZE64, &size))
  48                 err(EX_DATAERR, "ioctl(BLKGETSIZE64) failed");
  49         return size;
  50 }
  51
  52 static off_t get_size(int fd)
  53 {
  54         struct stat st;
  55
  56         if (fstat(fd, &st))
  57                 err(EX_DATAERR, "could not stat %i", fd);
  58
  59         if (S_ISREG(st.st_mode))
  60                 return st.st_size;
  61         else if (S_ISBLK(st.st_mode))
  62                 return get_blk_size(fd);
  63
  64         errno = EINVAL;
  65         err(EX_DATAERR, "unknown type of file");
  66 }
  67
  68 static void nuke(int fd, off_t offset, off_t max_size, unsigned char pattern)
  69 {
  70         static char mem[1024 * 1024];
  71         memset(mem, pattern, sizeof(mem));
  72         if (pattern)
  73                 printf("Writing 0x%X to the output\n", pattern);
  74
  75         if (lseek(fd, offset, SEEK_SET) != offset)
  76                 err(EX_DATAERR, "lseek(%"PRIu64"u) failed", offset);
  77
  78         unsigned long long speed = 0;
  79         struct timespec stime, etime, itime;
  80         clock_gettime(CLOCK_MONOTONIC, &stime);
  81         itime = stime;
  82
  83         off_t pos = offset, last_pos = 0;
  84         ssize_t ret;
  85         int fsync_pos = 0;
  86         while (pos < max_size) {
  87                 /* This will round up to sizeof(mem) ... */
  88                 ret = write(fd, mem, sizeof(mem));
  89                 pos += ret;
  90                 if (ret != sizeof(mem)) {
  91                         if (pos != max_size)
  92                                 printf("\nread() returned %zi (wanted %zu)\n%'llu MB/s over entire run\n",
  93                                         ret, sizeof(mem), mbps(&itime, &etime, pos));
  94                         return;
  95                 }
  96
  97                 unsigned long long eta = speed ? (max_size - pos) / (speed * 1000 * 1000) : 0;
  98                 printf("\r\e[2K%'llu bytes %u%% (%'llu MB/s) (ETA ~%llum%llus)",
  99                         (unsigned long long)pos, (unsigned)((pos * 100) / max_size), speed,
 100                         eta / 60, eta % 60);
 101
 102                 if ((++fsync_pos % 32) == 0) {
 103                         speed = mbps(&stime, &etime, pos - last_pos);
 104                         last_pos = pos;
 105                         fflush(stdout);
 106                         fsync(fd);
 107                 }
 108         }
 109
 110         printf("\n");
 111 }
 112
 113 static void usage(int status)
 114 {
 115         fprintf(
 116                 status ? stderr : stdout,
 117                 "Usage: ddnuke [options] <dev>\n"
 118                 "\n"
 119                 "Options:\n"
 120                 " -q            Run quietly\n"
 121                 " -y            Assume yes to all prompts\n"
 122                 " -o <offset>   Position to start writing\n"
 123                 " -r            Write three times: 0x00, then 0xaa, then 0x55\n"
 124         );
 125         exit(status);
 126 }
 127
 128 int main(int argc, char *argv[])
 129 {
 130         off_t offset = 0;
 131         const char *file;
 132         bool quiet = false;
 133         bool random = false;
 134         bool yes = false;
 135         int o;
 136
 137         setlocale(LC_NUMERIC, "en_US");
 138
 139         while ((o = getopt(argc, argv, "ho:qry")) != -1) {
 140                 switch (o) {
 141                 case 'o':
 142                         offset = atoll(optarg);
 143                         break;
 144                 case 'q':
 145                         quiet = true;
 146                         break;
 147                 case 'r':
 148                         random = true;
 149                         break;
 150                 case 'y':
 151                         yes = true;
 152                         break;
 153                 case 'h':
 154                         usage(EX_OK);
 155                         break;
 156                 default:
 157                         usage(EX_USAGE);
 158                         break;
 159                 }
 160         }
 161         if (argc != optind + 1)
 162                 usage(EX_USAGE);
 163         file = argv[optind];
 164
 165         int fd = open(file, O_WRONLY|O_CLOEXEC);
 166         if (fd == -1)
 167                 err(EX_NOINPUT, "open(%s) failed", file);
 168
 169         if (!quiet) {
 170                 pid_t pid;
 171                 const char *argv[] = {"fdisk", "-l", file, NULL};
 172                 if (posix_spawnp(&pid, argv[0], NULL, NULL, (char *const *)argv, NULL))
 173                         err(EX_OSERR, "spawn(%s %s) failed", argv[0], file);
 174                 waitpid(pid, NULL, 0);
 175                 printf("\n");
 176         }
 177
 178         if (!yes) {
 179                 printf("Do you want to wipe '%s'? (y/N) ", file);
 180                 fflush(stdout);
 181                 char c = 0;
 182                 if (fread(&c, 1, 1, stdin)) {/* don't care */}
 183                 if (tolower(c) != 'y')
 184                         errx(EX_UNAVAILABLE, "User decided not to wipe");
 185         }
 186
 187         off_t max_size = get_size(fd);
 188
 189         nuke(fd, offset, max_size, 0x00);
 190         if (random) {
 191                 nuke(fd, offset, max_size, 0xaa);
 192                 nuke(fd, offset, max_size, 0x55);
 193         }
 194
 195         return EX_OK;
 196 }