[dvdrip] / dvd-sector-copy.c

#define _GNU_SOURCE
#define _FILE_OFFSET_BITS 64

#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <math.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/time.h>

#include <getopt.h>

#include <linux/fs.h>

#include <dvdread/dvd_reader.h>
#include <dvdread/dvd_udf.h>
#include <dvdread/ifo_read.h>
#include <dvdread/ifo_types.h>

#define CTYPE_HACK(fn, ch) fn((unsigned char)(ch))
#define ISDIGIT(ch) CTYPE_HACK(isdigit, ch)
#define ISSPACE(ch) CTYPE_HACK(isspace, ch)

#ifdef DEBUG
#  define D(x) x
#else
#  define D(x)
#endif

#define N(v) (sizeof(v)/sizeof((v)[0]))

#define SECTORSZ 2048
#define SECTORS(n) (((n) + (SECTORSZ - 1))/SECTORSZ)

static const char *prog = "<unset>";
static int status = 0;

static void usage(FILE *fp)
{
  fprintf(fp,
	  "usage: %s [-c] [-R MAP] [-b OUTMAP] [-r [START]-[END]]\n"
	  "\tDEVICE OUTFILE\n",
	  prog);
}

static void vmoan(const char *fmt, va_list ap)
  { fprintf(stderr, "%s: ", prog); vfprintf(stderr, fmt, ap); }

__attribute__((format(printf, 1, 2)))
static void moan(const char *fmt, ...)
{
  va_list ap;

  va_start(ap, fmt); vmoan(fmt, ap); va_end(ap);
  fputc('\n', stderr);
}

__attribute__((noreturn, format(printf, 1, 2)))
static void bail(const char *fmt, ...)
{
  va_list ap;

  va_start(ap, fmt); vmoan(fmt, ap); va_end(ap);
  fputc('\n', stderr);
  exit(2);
}

__attribute__((noreturn, format(printf, 2, 3)))
static void bail_syserr(int err, const char *fmt, ...)
{
  va_list ap;

  va_start(ap, fmt); vmoan(fmt, ap); va_end(ap);
  if (err) fprintf(stderr, ": %s", strerror(errno));
  fputc('\n', stderr);
  exit(2);
}

static void carefully_write(int fd, const void *buf, size_t sz)
{
  const unsigned char *p = buf;
  ssize_t n;

  if (fd < 0) return;
  while (sz) {
    n = write(fd, p, sz);
    if (n < 0) {
      if (errno == EINTR) continue;
      bail_syserr(errno, "failed to write to output file");
    }
    if (!n) bail("unexpected short write to output file");
    p += n; sz -= n;
  }
}

#define DEFVEC(vtype, etype)						\
	typedef struct { etype *v; size_t n, sz; } vtype
#define VEC_INIT { 0, 0, 0 }
#define VEC_FREE(vv) do {						\
  free((vv)->v); (vv)->v 0; (vv)->n = (vv)->sz = 0;			\
} while (0)
#define VEC_PUSH(p, vv) do {						\
  size_t _want;								\
  if ((vv)->n >= (vv)->sz) {						\
    (vv)->sz = (vv)->sz ? 2*(vv)->sz : 32;				\
    _want = (vv)->sz*sizeof(*(vv)->v);					\
    (vv)->v = realloc((vv)->v, _want);					\
    if (!(vv)->v) bail("out of memory allocating %zu bytes", _want);	\
  }									\
  (p) = &(vv)->v[(vv)->n++];						\
} while (0)

enum { RAW, IFO, VOB, BUP };
typedef uint_least32_t ident;

static inline ident mkident(unsigned kind, unsigned title, unsigned part)
  { return (((ident)kind << 0) | ((ident)title << 8) | ((ident)part << 16)); }
static inline unsigned id_kind(ident id) { return ((id >> 0)&0x0ff); }
static inline unsigned id_title(ident id) { return ((id >> 8)&0x0ff); }
static inline unsigned id_part(ident id) { return ((id >> 16)&0x0ff); }

#define MAXFNSZ (1 + 8 + 1 + 12 + 1)

static void store_filename(char *buf, ident id)
{
  switch (id_kind(id)) {
    case RAW:
      sprintf(buf, "#<raw device>");
      break;
    case IFO:
      if (!id_title(id)) sprintf(buf, "/VIDEO_TS/VIDEO_TS.IFO");
      else sprintf(buf, "/VIDEO_TS/VTS_%02u_0.IFO", id_title(id));
      break;
    case BUP:
      if (!id_title(id)) sprintf(buf, "/VIDEO_TS/VIDEO_TS.BUP");
      else sprintf(buf, "/VIDEO_TS/VTS_%02u_0.BUP", id_title(id));
      break;
    case VOB:
      if (!id_title(id)) sprintf(buf, "/VIDEO_TS/VIDEO_TS.VOB");
      else
	sprintf(buf, "/VIDEO_TS/VTS_%02u_%u.VOB", id_title(id), id_part(id));
      break;
    default:
      abort();
  }
}

typedef uint_least32_t secaddr;
#define PRIuSEC PRIuLEAST32
#define SECLIMIT 0x00400000

#define MAXFILES (1 + 2*99 + 1)
struct file {
  ident id;
  secaddr start, end;
};
DEFVEC(file_v, struct file);
static file_v filetab = VEC_INIT;

enum { EV_STOP, EV_BEGIN, EV_END, EV_WRITE };
struct event {
  unsigned char ev, file;
  secaddr pos;
};
DEFVEC(event_v, struct event);
static event_v eventq = VEC_INIT;

static int compare_event(const void *a, const void *b)
{
  const struct event *eva = a, *evb = b;

  if (eva->pos < evb->pos) return (-1);
  else if (eva->pos > evb->pos) return (+1);

  if (eva->ev < evb->ev) return (-1);
  else if (eva->ev > evb->ev) return (+1);

  if (eva->file < evb->file) return (-1);
  else if (eva->file > evb->file) return (+1);

  return (0);
}

typedef uint_least32_t bits;
static bits live[(MAXFILES + 31)/32];

static inline int livep(unsigned i)
  { return (live[i/32]&((bits)1 << (i%32))); }
static inline void set_live(unsigned i)
  { live[i/32] |= (bits)1 << (i%32); }
static inline void clear_live(unsigned i)
  { live[i/32] &= ~((bits)1 << (i%32)); }
static inline int least_live(void)
{
  unsigned i, n = (filetab.n + 32)/32;
  bits b;

  for (i = 0; i < n; i++) { b = live[i]; if (b) goto found; }
  return (-1);
found:
  i *= 32;
  if (!(b&0x0000ffff)) { b >>= 16; i += 16; }
  if (!(b&0x000000ff)) { b >>=  8; i +=  8; }
  if (!(b&0x0000000f)) { b >>=  4; i +=  4; }
  if (!(b&0x00000003)) { b >>=  2; i +=  2; }
  if (!(b&0x00000001)) { b >>=  1; i +=  1; }
  assert(b&1);
  return (i);
}

static void put_event(unsigned evtype, unsigned file, secaddr pos)
{
  struct event *ev;

  VEC_PUSH(ev, &eventq);
  ev->ev = evtype; ev->file = file; ev->pos = pos;
}

static void put_file(ident id, secaddr start, secaddr end)
{
  struct file *f;
  size_t i;

  VEC_PUSH(f, &filetab); i = f - filetab.v;
  f->id = id; f->start = start; f->end = end;
  put_event(EV_BEGIN, i, start);
  put_event(EV_END, i, end);
}

static void put_menu(dvd_reader_t *dvd, unsigned title)
{
  ident id = mkident(VOB, title, 0);
  char fn[MAXFNSZ];
  secaddr start, len;

  store_filename(fn, id);
  start = UDFFindFile(dvd, fn, &len); if (!start) return;
#ifdef DEBUG
      printf(";; %8"PRIuSEC" .. %-8"PRIuSEC": %s\n",
	     start, start + SECTORS(len), fn);
#endif
  put_file(id, start, start + SECTORS(len));
}

static void put_title(dvd_reader_t *dvd, unsigned title)
{
  char fn[MAXFNSZ];
  secaddr start[9], len[9];
  unsigned i, npart;

  for (i = 0; i < 9; i++) {
    store_filename(fn, mkident(VOB, title, i + 1));
    start[i] = UDFFindFile(dvd, fn, &len[i]); if (!start[i]) break;
  }
  npart = i; if (!npart) return;

#ifdef DEBUG
  for (i = 0; i < npart; i++) {
    store_filename(fn, mkident(VOB, title, i + 1));
    printf(";; %8"PRIuSEC" .. %-8"PRIuSEC": %s\n",
	   start[i], start[i] + SECTORS(len[i]), fn);
  }
#endif

  if (npart > 1)
    for (i = 0; i < npart - 1; i++) {
      if (len[i]%SECTORSZ)
	bail("title %u part %u length = %"PRIuSEC" not a multiple of %d",
	     title, i, len[i], SECTORSZ);
      if (start[i] + len[i]/SECTORSZ != start[i + 1])
	bail
	  ("title %u part %u end = %"PRIuSEC" /= part %u start = %"PRIuSEC"",
	   title, i, start[i] + len[i]/SECTORSZ, i + 1, start[i + 1]);
    }

  put_file(mkident(VOB, title, 1),
	   start[0], start[npart - 1] + SECTORS(len[npart - 1]));
}

static int progresslen = 0;

static void clear_progress_internal(void)
{
  while (progresslen) { fputs("\b \b", stdout); progresslen--; }
  putchar('\r');
}
static void clear_progress(void)
  { clear_progress_internal(); fflush(stdout); }
#ifdef DEBUG
static void debug_clear_progress(void)
  { if (progresslen) { putchar('\n'); progresslen = 0; } }
#endif
static void vappend_progress(const char *fmt, va_list ap)
  { progresslen += vprintf(fmt, ap); }
__attribute__((format(printf, 1, 2)))
static void append_progress(const char *fmt, ...)
{
  va_list ap;

  va_start(ap, fmt);
  vappend_progress(fmt, ap);
  va_end(ap);
}
__attribute__((format(printf, 1, 2)))
static void print_progress(const char *fmt, ...)
{
  va_list ap;

  va_start(ap, fmt);
  clear_progress_internal();
  vappend_progress(fmt, ap);
  va_end(ap);
}

unsigned flags;
#  define F_ALLPROGRESS 1u
static secaddr last_pos, limit, nsectors, ndone;
static struct timeval last_time;
static double wsum, wcount;
static struct file *file;

static void report_progress(secaddr pos)
{
  char etastr[32];
  struct timeval now;
  int eta;
  double percent, t, f, g, rate;
  char *unit;

#define ALPHA 0.02
#define BETA (1 - ALPHA)

  gettimeofday(&now, 0);
  t = (now.tv_sec - last_time.tv_sec) +
    (now.tv_usec - last_time.tv_usec)/1000000.0;

  if (t) {
    g = wcount ? pow(BETA, t) : 0.0; f = (1 - g)/(1 - BETA);
    wsum = f*(pos - last_pos)/t + g*wsum;
    wcount = f + g*wcount;
    ndone += pos - last_pos;
    last_time = now; last_pos = pos;
  }

  if (!wsum || !wcount)
    { rate = 0; strcpy(etastr, "???"); }
  else {
    rate = wsum/wcount;
    eta = (int)((nsectors - ndone)/rate);
    sprintf(etastr, "%d:%02d:%02d", eta/3600, (eta/60)%60, eta%60);
  }

  rate *= SECTORSZ; unit = "";
  if (rate > 128) { rate /= 1024; unit = "k"; }
  if (rate > 128) { rate /= 1024; unit = "M"; }
  if (rate > 128) { rate /= 1024; unit = "G"; }

  if (flags&F_ALLPROGRESS) percent = pos*100.0/limit;
  else percent = ndone*100.0/nsectors;
  print_progress
    ("copied %.1f%% (%"PRIuSEC" of %"PRIuSEC"; %.1f %sB/s, ETA %s)",
     percent, pos, limit,  rate, unit, etastr);
  if (file && id_kind(file->id) == VOB) {
    append_progress(" -- %s %d %3.1f%%",
		    id_part(file->id) ? "title" : "menu",
		    id_title(file->id),
		    (pos - file->start)*100.0/
		      (file->end - file->start));
  }

#undef ALPHA
#undef BETA
}

static dvd_reader_t *dvd;
static int dvdfd = -1, outfd = -1;
static dvd_file_t *vob;
static const char *mapfile; static FILE *mapfp;

struct badblock { secaddr start, end; };
DEFVEC(badblock_v, struct badblock);
static badblock_v badblocks = VEC_INIT;

static int compare_badblock(const void *a, const void *b)
{
  const struct badblock *ba = a, *bb = b;

  if (ba->start < bb->start) return (-1);
  else if (ba->start > bb->start) return (+1);

  if (ba->end < bb->end) return (-1);
  else if (ba->end > bb->end) return (+1);

  return (0);
}

static ssize_t read_sectors(secaddr pos, void *buf, secaddr want)
{
  ssize_t n, done;
  size_t lo, mid, hi;
  int fakeerr = 0;
  struct badblock *bad, *best;
  unsigned char *p = buf;

  if (badblocks.n) {
    best = 0; lo = 0; hi = badblocks.n;
#ifdef DEBUG
    debug_clear_progress();
    printf(";; searching badblocks for %"PRIuSEC" .. %"PRIuSEC"\n",
	   pos, pos + want);
#endif
    while (lo < hi) {
      mid = lo + (hi - lo)/2; bad = &badblocks.v[mid];
#ifdef DEBUG
      printf(";;   try %zu (%"PRIuSEC" .. %"PRIuSEC")... ",
	     mid, bad->start, bad->end);
#endif
      if (pos < bad->start) { D( printf("high\n"); ) best = bad; hi = mid; }
      else if (pos >= bad->end) { D( printf("low\n"); ) lo = mid + 1; }
      else { D( printf("match!\n"); ) errno = EIO; return (-1); }
    }
#ifdef DEBUG
    if (best)
      printf(";;   next is %"PRIuSEC" .. %"PRIuSEC"\n",
	     best->start, best->end);
#endif
    if (best && pos + want > best->start)
      { want = best->start - pos; fakeerr = EIO; }
  }
  done = 0;
  while (want) {
    if (vob)
      { errno = 0; n = DVDReadBlocks(vob, pos - file->start, want, p); }
    else if (file) {
      if (lseek(dvdfd, (off_t)pos*SECTORSZ, SEEK_SET) < 0)
	bail_syserr(errno, "failed to seek to sector %"PRIuSEC"", pos);
      errno = 0; n = read(dvdfd, p, want*SECTORSZ);
      if (n >= 0) n /= SECTORSZ;
    } else {
      memset(p, 0, want*SECTORSZ);
      n = want;
    }

    if (n > 0) { done += n; pos += n; p += n*SECTORSZ; want -= n; }
    else if (!n || errno != EINTR) break;
  }
  if (fakeerr && !errno) errno = fakeerr;
  return (!done && errno ? -1 : done);
}

static void report_bad_blocks_progress(secaddr lo, secaddr hi, int err)
{
  report_progress(hi);

  if (lo == hi) append_progress(": retrying bad sector");
  else
    append_progress(": %"PRIuSEC" bad %s",
		    hi - lo, hi == lo + 1 ? "sector" : "sectors");
  if (err && err != EIO) append_progress(" (%s)", strerror(err));
  fflush(stdout);
}

static void recovered(secaddr bad_lo, secaddr bad_hi)
{
  clear_progress();
  moan("skipping %"PRIuSEC" bad sectors (%"PRIuSEC" .. %"PRIuSEC")",
       bad_hi - bad_lo, bad_lo, bad_hi);
  if (mapfile) {
    if (!mapfp) {
      mapfp = fopen(mapfile, "w");
      if (!mapfp)
	bail_syserr(errno, "failed to open bad-sector map file `%s'",
		    optarg);
      fprintf(mapfp, "## bad sector map\n\n");
    }
    fprintf(mapfp, "%"PRIuSEC" %"PRIuSEC"\n", bad_lo, bad_hi);
    fflush(mapfp);
    if (ferror(mapfp))
      bail_syserr(errno, "error writing bad-sector map file");
  }
  if (lseek(outfd, (off_t)(bad_hi - bad_lo)*SECTORSZ, SEEK_CUR) < 0)
    bail_syserr(errno, "failed to seek past bad sectors");
  status = 1;
}

struct recoverybuf {
  unsigned char *buf;
  secaddr sz, pos, start, end;
};

static void rearrange_sectors(struct recoverybuf *r,
			      secaddr dest, secaddr src, secaddr len)
{
  assert(dest + len <= r->sz);
  assert(src + len <= r->sz);
  memmove(r->buf + dest*SECTORSZ, r->buf + src*SECTORSZ, len*SECTORSZ);
}

#ifdef DEBUG
__attribute__((format(printf, 2, 3)))
static void show_recovery_buffer_map(const struct recoverybuf *r,
				     const char *what, ...)
{
  va_list ap;

  va_start(ap, what);
  debug_clear_progress();
  printf(";; recovery buffer (");
  vprintf(what, ap);
  printf("): "
	 "(%"PRIuSEC") ..%"PRIuSEC".. "
	 "[%"PRIuSEC" ..%"PRIuSEC".. %"PRIuSEC"] "
	 "..%"PRIuSEC".. (%"PRIuSEC")\n",
	 r->pos, r->start,
	 r->pos + r->start, r->end - r->start, r->pos + r->end,
	 r->sz - r->end, r->pos + r->sz);
  va_end(ap);
  assert(r->start <= r->end);
  assert(r->end <= r->sz);
}
#endif

static ssize_t recovery_read_sectors(struct recoverybuf *r,
				     secaddr pos, secaddr off, secaddr want)
{
  ssize_t n;

  assert(off <= r->sz); assert(want <= r->sz - off);
  n = read_sectors(pos, r->buf + off*SECTORSZ, want);
  return (n);
}

static ssize_t recovery_read(struct recoverybuf *r,
			     secaddr pos, secaddr want)
{
  secaddr diff, pp, nn;
  ssize_t n;

#ifdef DEBUG
  debug_clear_progress();
  show_recovery_buffer_map(r, "begin(%"PRIuSEC", %"PRIuSEC")", pos, want);
#endif

  if (pos < r->pos) {
    diff = r->pos - pos;
    if (r->start + diff >= r->sz) {
      r->pos = pos; r->start = r->end = 0;
#ifdef DEBUG
      show_recovery_buffer_map(r, "cleared; shift up by %"PRIuSEC"", diff);
#endif
    } else {
      if (r->end + diff > r->sz) r->end = r->sz - diff;
      rearrange_sectors(r, r->start + diff, r->start, r->end - r->start);
      r->pos -= diff; r->start += diff; r->end += diff;
#ifdef DEBUG
      show_recovery_buffer_map(r, "shifted up by %"PRIuSEC"", diff);
#endif
    }
  } else if (pos > r->pos + r->end) {
      r->pos = pos; r->start = r->end = 0;
#ifdef DEBUG
      show_recovery_buffer_map(r, "cleared; beyond previous region");
#endif
  } else if (pos + want > r->pos + r->sz) {
    diff = (pos + want) - (r->pos + r->sz);
    if (r->end <= diff) {
      r->pos = pos; r->start = r->end = 0;
#ifdef DEBUG
      show_recovery_buffer_map(r, "cleared; shift down by %"PRIuSEC"", diff);
#endif
    } else {
      if (r->start < diff) r->start = diff;
      rearrange_sectors(r, r->start - diff, r->start, r->end - r->start);
      r->pos += diff; r->start -= diff; r->end -= diff;
#ifdef DEBUG
      show_recovery_buffer_map(r, "shifted down by %"PRIuSEC"", diff);
#endif
    }
  }

  if (pos < r->pos + r->start) {
    pp = pos - r->pos; nn = r->start - pp;
#ifdef DEBUG
    printf(";; read low (%"PRIuSEC"@%"PRIuSEC", %"PRIuSEC")", pos, pp, nn);
    fflush(stdout);
#endif
    n = recovery_read_sectors(r, pos, pp, nn);
#ifdef DEBUG
    printf(" -> %zd\n", n);
#endif
    if (n != nn) {
      if (n >= 0 && n > want) n = want;
      goto end;
    }
    r->start = pp;
#ifdef DEBUG
    show_recovery_buffer_map(r, "joined new region");
#endif
  }

  if (pos + want > r->pos + r->end) {
    pp = r->end; nn = (pos + want) - (r->pos + r->end);
#ifdef DEBUG
    printf(";; read high (%"PRIuSEC"@%"PRIuSEC", %"PRIuSEC")",
	   r->pos + pp, pp, nn);
    fflush(stdout);
#endif
    n = recovery_read_sectors(r, pos + pp, pp, nn);
#ifdef DEBUG
    printf(" -> %zd\n", n);
#endif
    if (n > 0) {
      r->end += n;
#ifdef DEBUG
      show_recovery_buffer_map(r, "joined new region");
#endif
    }
  }

  n = r->pos + r->end - pos;
  if (!n && want) n = -1;

end:
#ifdef DEBUG
  show_recovery_buffer_map(r, "done; return %zd", n);
#endif
  return (n);
}

static secaddr run_length_wanted(secaddr pos, secaddr badlen,
				 secaddr sz, secaddr end)
{
  secaddr want;

  want = 3*badlen/2;
  if (!want) want = 1;
  if (want > end - pos) want = end - pos;
  if (want > sz) want = sz;
  return (want);
}

static ssize_t find_good_sector(secaddr *pos_inout, secaddr end,
				unsigned char *buf, secaddr sz)
{
  int i;
  secaddr pos = *pos_inout, bad_lo, bad_hi, good, step, want;
  struct recoverybuf r;
  ssize_t n;

  r.buf = buf; r.sz = sz; r.pos = r.start = r.end = 0;
  report_bad_blocks_progress(pos, pos, errno);

  want = sz; if (want > end - pos) want = end - pos;
  for (i = 0; i < 4; i++) {
    n = recovery_read(&r, pos, want);
#ifdef DEBUG
    debug_clear_progress();
    printf(";; [retry] try reading %"PRIuSEC" .. %"PRIuSEC" -> %zd\n",
	   pos, pos + want, n);
#endif
    if (n > 0) {
      clear_progress();
      moan("sector %"PRIuSEC" read ok after retry", pos);
      return (n);
    }
  }

  bad_lo = pos; bad_hi = pos + 1;
  for (;;) {
    report_bad_blocks_progress(bad_lo, bad_hi, errno);
    if (bad_hi >= end) {
      clear_progress();
      moan("giving up on this extent");
      recovered(bad_lo, end); *pos_inout = end; return (0);
    }
    step = 2*(bad_hi - bad_lo); if (step > end - bad_lo) step = end - bad_lo;
    pos = bad_lo + step - 1;
    want = run_length_wanted(pos, step, sz, end);
    n = recovery_read(&r, pos, want);
#ifdef DEBUG
    debug_clear_progress();
    printf(";; [bound] try reading %"PRIuSEC" .. %"PRIuSEC" -> %zd\n",
	   pos, pos + want, n);
#endif
    if (n == want) break;
    if (n < 0) n = 0;
    bad_hi = pos + n + 1;
  }

  good = pos;
  while (good > bad_hi) {
    report_bad_blocks_progress(bad_lo, bad_hi, errno);
    pos = bad_hi + (good - bad_hi)/2;
    step = pos - bad_lo;
    want = run_length_wanted(pos, step, sz, end);
    n = recovery_read(&r, pos, want);
#ifdef DEBUG
    debug_clear_progress();
    printf(";; [limit] try reading %"PRIuSEC" .. %"PRIuSEC" -> %zd\n",
	   pos, pos + want, n);
#endif
    if (n < 0) n = 0;
    if (n == want) good = pos;
    else bad_hi = pos + n + 1;
  }
  recovered(bad_lo, bad_hi); *pos_inout = good;
  if (good < r.pos + r.start || r.pos + r.end <= good)
    n = 0;
  else {
    n = r.pos + r.end - good;
    rearrange_sectors(&r, 0, good - r.pos, n);
  }
#ifdef DEBUG
  show_recovery_buffer_map(&r, "returning %zd good sectors at %"PRIuSEC"",
			   n, good);
#endif
  return (n);
}

static void emit(secaddr start, secaddr end)
{
#define BUFSECTORS 512

  int least;
  unsigned char buf[BUFSECTORS*SECTORSZ];
  secaddr pos;
  size_t want;
  ssize_t n;
  static int first_time = 1;
#ifdef DEBUG
  struct file *f;
  char fn[MAXFNSZ];
  int act = -1;
  int i;
#endif

  least = least_live();

#ifdef DEBUG
  printf(";; %8"PRIuSEC" .. %"PRIuSEC"\n", start, end);

  for (i = 0; i < filetab.n; i++) {
    if (!livep(i)) continue;
    if (act == -1) act = i;
    f = &filetab.v[i]; store_filename(fn, f->id);
    printf(";;\t\t%8"PRIuSEC" .. %-8"PRIuSEC" %s\n",
	   start - f->start, end - f->start, fn);
  }
  if (act == -1) printf(";;\t\t#<no live source>\n");
  assert(act == least);
#endif

  if (least == -1)
    { file = 0; vob = 0; }
  else {
    file = &filetab.v[least];
    switch (id_kind(file->id)) {
      case RAW:
	vob = 0;
	break;
      case VOB:
	if (first_time) { clear_progress(); first_time = 0; }
	vob = DVDOpenFile(dvd, id_title(file->id),
			  id_part(file->id)
			    ? DVD_READ_TITLE_VOBS
			    : DVD_READ_MENU_VOBS);
	if (!vob)
	  bail("failed to open %s %u",
	       id_part(file->id) ? "title" : "menu",
	       id_title(file->id));
	break;
      default:
	abort();
    }
  }

  pos = start;
  while (pos < end) {
    want = end - pos; if (want > BUFSECTORS) want = BUFSECTORS;
    n = read_sectors(pos, buf, want);

    if (n <= 0) n = find_good_sector(&pos, end, buf, BUFSECTORS);
    if (n > 0) { carefully_write(outfd, buf, n*SECTORSZ); pos += n; }
    report_progress(pos); fflush(stdout);
  }

  if (vob) { DVDCloseFile(vob); vob = 0; }

#undef BUFSECTORS
}

#ifdef notdef
static void logfn(void *p, dvd_logger_level_t lev,
		  const char *fmt, va_list ap)
{
  switch (lev) {
    case DVD_LOGGER_LEVEL_ERROR:
      fprintf("%s (libdvdread error): ", prog);
      break;
    case DVD_LOGGER_LEVEL_WARN:
      fprintf("%s (libdvdread warning): ", prog);
      break;
    default:
      return;
  }
  vfprintf(stderr, fmt, ap);
  fputc('\n', stderr);
}
static const dvd_logger_cb logger = { logfn };
#endif

struct buf {
  char *p;
  size_t n, sz;
};
#define BUF_INIT { 0, 0, 0 }
#define BUF_REWIND(b) do { (b)->n = 0; } while (0)
#define BUF_FREE(b) do {						\
  buf *_b = (b);							\
  free(_b->p); _b->p = 0; _b->n = _b->sz = 0;				\
} while (0)
#define BUF_PUTC(b, ch) do {						\
  struct buf *_b = (b);							\
  if (_b->n >= _b->sz) {						\
    _b->sz = _b->sz ? 2*_b->sz : 32;					\
    _b->p = realloc(_b->p, _b->sz);					\
    if (!_b->p) bail("out of memory allocating %zu bytes", _b->sz);	\
  }									\
  _b->p[_b->n] = (ch);							\
} while (0)

static int read_line(FILE *fp, struct buf *b)
{
  int ch;

  ch = getc(fp);
  if (ch == EOF)
    return (-1);
  else if (ch != '\n') do {
    BUF_PUTC(b, ch); b->n++;
    ch = getc(fp);
  } while (ch != EOF && ch != '\n');
  BUF_PUTC(b, 0);
  return (0);
}

#define PRF_HYPHEN 1u
static int parse_range(const char *p, unsigned f,
		       secaddr *start_out, secaddr *end_out)
{
  char *q;
  int err, rc;
  unsigned long start, end;

  err = errno;

  if (ISDIGIT(*p)) {
    start = strtoul(p, &q, 0);
    if (errno || start >= SECLIMIT) { rc = -1; goto end; }
    *start_out = start; p = q;
  } else if (!(f&PRF_HYPHEN))
    { rc = -1; goto end; }
  else
    start = 0;

  if (f&PRF_HYPHEN) {
    if (*p != '-')  { rc = -1; goto end; }
    p++;
  } else {
    if (!ISSPACE(*p)) { rc = -1; goto end; }
    do p++; while (ISSPACE(*p));
  }

  if (ISDIGIT(*p)) {
    end = strtoul(p, &q, 0);
    if (errno || end > SECLIMIT || end < start) { rc = -1; goto end; }
    *end_out = end; p = q;
  } else if (!(f&PRF_HYPHEN))
    { rc = -1; goto end; }

  if (!(f&PRF_HYPHEN)) while (ISSPACE(*p)) p++;
  if (*p) { rc = -1; goto end; }

  rc = 0;
end:
  errno = err;
  return (rc);
}

int main(int argc, char *argv[])
{
  unsigned f = 0;
  char *p;
  uint64_t volsz;
  secaddr pos;
  off_t off;
  secaddr start, end, last;
  const struct event *ev;
  const char *device, *outfile;
  struct badblock *bad;
  int opt, blksz;
  unsigned n;
  size_t i;
  FILE *fp;
  struct buf buf = BUF_INIT;
  struct stat st;
#ifdef DEBUG
  const struct file *file;
  char fn[MAXFNSZ];
#endif

#define f_bogus 1u
#define f_continue 2u
#define f_fixup 4u
#define f_write 256u

  p = strrchr(argv[0], '/'); prog = p ? p + 1 : argv[0];
  for (;;) {
    opt = getopt(argc, argv, "hFR:X:b:cr:"); if (opt < 0) break;
    switch (opt) {
      case 'h': usage(stderr); exit(0);
      case 'F': f |= f_fixup; break;
      case 'R':
	fp = fopen(optarg, "r");
	if (!fp)
	  bail_syserr(errno, "failed to open ranges file `%s'", optarg);
	i = 0; last = -1;
	for (;;) {
	  BUF_REWIND(&buf); if (read_line(fp, &buf)) break;
	  p = buf.p; i++;
	  while (ISSPACE(*p)) p++;
	  if (!*p || *p == '#') continue;
	  if (parse_range(p, 0, &start, &end) ||
	      (last <= SECLIMIT && start < last))
	    bail("bad range `%s' at `%s' line %zu", buf.p, optarg, i);
	  if (start < end) {
	    if (start == last)
	      eventq.v[eventq.n - 1].pos = end;
	    else {
	      put_event(EV_WRITE, 0, start);
	      put_event(EV_STOP, 0, end);
	    }
	    last = end;
	  }
	}
	if (ferror(fp))
	  bail_syserr(errno, "failed to read ranges file `%s'", optarg);
	break;
      case 'X':
	fp = fopen(optarg, "r");
	if (!fp)
	  bail_syserr(errno, "failed to open bad-blocks file `%s'", optarg);
	i = 0; last = -1;
	for (;;) {
	  BUF_REWIND(&buf); if (read_line(fp, &buf)) break;
	  p = buf.p; i++;
	  while (ISSPACE(*p)) p++;
	  if (!*p || *p == '#') continue;
	  if (parse_range(p, 0, &start, &end) ||
	      (last <= SECLIMIT && start < last))
	    bail("bad range `%s' at `%s' line %zu", buf.p, optarg, i);
	  if (start < end)
	    { VEC_PUSH(bad, &badblocks); bad->start = start; bad->end = end; }
	}
	if (ferror(fp))
	  bail_syserr(errno, "failed to read bad-blocks file `%s'", optarg);
	break;
      case 'b':
	if (mapfile) bail("can't have multiple map files");
	mapfile = optarg;
	break;
      case 'c': f |= f_continue; break;
      case 'r':
	start = 0; end = -1;
	if (parse_range(optarg, PRF_HYPHEN, &start, &end))
	  bail("bad range `%s'", optarg);
	if (start < end) {
	  put_event(EV_WRITE, 0, start);
	  if (end <= SECLIMIT) put_event(EV_STOP, 0, end);
	}
	break;
      default: f |= f_bogus; break;
    }
  }
  if (argc - optind != 2) f |= f_bogus;
  if (f&f_bogus) { usage(stderr); exit(2); }

  device = argv[optind]; outfile = argv[optind + 1];

  if (badblocks.n) {
    qsort(badblocks.v, badblocks.n, sizeof(struct badblock),
	  compare_badblock);
#ifdef DEBUG
    printf(";; fake bad blocks:\n");
    for (i = 0; i < badblocks.n; i++)
      printf(";;\t%8"PRIuSEC" .. %"PRIuSEC"\n",
	     badblocks.v[i].start, badblocks.v[i].end);
#endif
  }

  dvdfd = open(device, O_RDONLY);
  if (dvdfd < 0)
    bail_syserr(errno, "failed to open device `%s'", device);
  if (fstat(dvdfd, &st))
    bail_syserr(errno, "failed to stat device `%s'", device);
  if (S_ISREG(st.st_mode)) {
    blksz = SECTORSZ;
    volsz = st.st_size;
  } else if (S_ISBLK(st.st_mode)) {
    if (ioctl(dvdfd, BLKSSZGET, &blksz))
      bail_syserr(errno, "failed to get block size for `%s'", device);
    if (ioctl(dvdfd, BLKGETSIZE64, &volsz))
      bail_syserr(errno, "failed to get volume size for `%s'", device);
  } else
    bail("can't use `%s' as source: expected file or block device", device);

  if (blksz != SECTORSZ)
    bail("device `%s' block size %d /= %d", device, blksz, SECTORSZ);
  if (volsz%SECTORSZ)
    bail("device `%s' volume size %"PRIu64" not a multiple of %d",
	 device, volsz, SECTORSZ);

  if (outfile) {
    outfd = open(outfile, O_WRONLY | O_CREAT, 0666);
    if (outfd < 0)
      bail_syserr(errno, "failed to create output file `%s'", outfile);
  }

  if (f&f_continue) {
    off = lseek(outfd, 0, SEEK_END);
    if (off < 0)
      bail_syserr(errno, "failed to seek to end of output file `%s'",
		  outfile);
    put_event(EV_WRITE, 0, off/SECTORSZ);
  } else if (!eventq.n && !(f&f_fixup))
    put_event(EV_WRITE, 0, 0);

#ifdef notdef
  dvd = DVDOpen2(0, &logger, device);
#else
  dvd = DVDOpen(device);
#endif
  if (!dvd) bail("failed to open DVD on `%s'", device);

  /* It's fast enough just to check everything. */
  put_menu(dvd, 0);
  for (i = 1; i < 100; i++) {
    put_menu(dvd, i);
    put_title(dvd, i);
  }
  put_file(mkident(RAW, 0, 0), 0, volsz/SECTORSZ);
  assert(filetab.n <= MAXFILES);

  for (i = 0, limit = 0; i < filetab.n; i++)
    if (filetab.v[i].end > limit) limit = filetab.v[i].end;

  if (end > limit) end = limit;

#ifdef DEBUG
  printf("\n;; files:\n");
  for (i = 0; i < filetab.n; i++) {
    file = &filetab.v[i];
    store_filename(fn, file->id);
    printf(";;\t%8"PRIuSEC" %s\n", file->start, fn);
  }
#endif

  qsort(eventq.v, eventq.n, sizeof(struct event), compare_event);

  f &= ~f_write; start = 0; n = 0;
  for (i = 0; i < eventq.n; i++) {
    ev = &eventq.v[i];
    switch (ev->ev) {
      case EV_WRITE:
	if (f&f_write)
	  bail("overlapping ranges: range from %"PRIuSEC" still open at %"PRIuSEC"",
	       start, ev->pos);
	n++; f |= f_write; start = ev->pos;
	break;
      case EV_STOP:
	f &= ~f_write;
	break;
    }
  }

  f &= ~f_write; start = 0;
  for (i = 0; i < eventq.n; i++) {
    ev = &eventq.v[i];
    switch (ev->ev) {
      case EV_WRITE: start = ev->pos; f |= f_write; break;
      case EV_STOP: nsectors += ev->pos - start; f &= ~f_write; break;
    }
    if (ev->pos >= limit) break;
    if (f&f_fixup) start = ev->pos;
  }
  eventq.n = i;
  if (f&f_fixup) {
    put_event(EV_WRITE, 0, start);
    n++; f |= f_write;
  }
  if (f&f_write) {
    nsectors += limit - start;
    put_event(EV_STOP, 0, limit);
  }
  if (n == 1 && (f&f_write)) flags |= F_ALLPROGRESS;
  f &= ~f_write;

#ifdef DEBUG
  printf("\n;; event sweep:\n");
#endif
  for (pos = 0, i = 0; i < eventq.n; i++) {
    ev = &eventq.v[i];
    if (ev->pos > pos) {
      if (f&f_write) emit(pos, ev->pos);
      pos = ev->pos;
#ifdef DEBUG
      debug_clear_progress();
      printf(";;\n");
#endif
    }
    switch (ev->ev) {
      case EV_BEGIN:
	set_live(ev->file);
#ifdef DEBUG
	store_filename(fn, filetab.v[ev->file].id);
	debug_clear_progress();
	printf(";; %8"PRIuSEC": begin `%s'\n", pos, fn);
#endif
	break;
      case EV_WRITE:
	gettimeofday(&last_time, 0); last_pos = pos;
	if (lseek(outfd, (off_t)ev->pos*SECTORSZ, SEEK_SET) < 0)
	  bail_syserr(errno,
		      "failed to seek to resume position "
		      "(sector %"PRIuSEC") in output file `%s'",
		      ev->pos, outfile);
#ifdef DEBUG
	debug_clear_progress();
	printf(";; %8"PRIuSEC": begin write\n", pos);
#endif
	f |= f_write;
	break;
      case EV_STOP:
	f &= ~f_write;
#ifdef DEBUG
	debug_clear_progress();
	printf(";; %8"PRIuSEC": end write\n", pos);
#endif
	break;
      case EV_END:
	clear_live(ev->file);
#ifdef DEBUG
	store_filename(fn, filetab.v[ev->file].id);
	debug_clear_progress();
	printf(";; %8"PRIuSEC": end `%s'\n", pos, fn);
#endif
	break;
      default: abort();
    }
  }

  if (progresslen) putchar('\n');

  if (ftruncate(outfd, (off_t)limit*SECTORSZ) < 0)
    bail_syserr(errno, "failed to set output file `%s' length", outfile);

  if (dvd) DVDClose(dvd);
  if (dvdfd >= 0) close(dvdfd);
  if (outfd >= 0) close(outfd);
  if (mapfp) {
    if (ferror(mapfp) || fclose(mapfp))
      bail_syserr(errno, "error writing bad-sector map file");
  }

#undef f_bogus
#undef f_continue
#undef f_fixup
#undef f_write

  return (status);
}