interface.c

刻录光盘的程序

#endif
	if (!S_ISBLK(statstruct->st_mode)) {
	    fprintf(stderr, "%s is not a block device\n",pdev_name);
	    exit(1);
	}
	if (interface != COOKED_IOCTL) {
	    fprintf(stderr, "cdrom device (%s) is not of type generic SCSI. "
		    "Setting interface to cooked_ioctl.\n", pdev_name);
	    interface = COOKED_IOCTL;
	}
	break;
#endif
    }
#endif
    if (global.overlap >= global.nsectors)
      global.overlap = global.nsectors-1;
}

/* open the cdrom device */
static int OpenCdRom ( pdev_name )
	char *pdev_name;
{
  int retval = 0;
  struct stat fstatstruct;

  /*  The device (given by pdevname) can be:
      a. an SCSI device specified with a /dev/xxx name,
      b. an SCSI device specified with bus,target,lun numbers,
      c. a non-SCSI device such as ATAPI or proprietary CDROM devices.
   */
#ifdef HAVE_IOCTL_INTERFACE
  struct stat statstruct;
  int have_named_device = 0;

  have_named_device = strchr(pdev_name, ':') == NULL
			 && memcmp(pdev_name, "/dev/", 5) == 0;

  if (have_named_device) {
    if (stat(pdev_name, &statstruct)) {
      fprintf(stderr, "cannot stat device %s\n", pdev_name);
      exit(1);
    } else {
      Check_interface_for_device( &statstruct, pdev_name );
    }
  }
#endif

  if (interface == GENERIC_SCSI) {
	char	errstr[80];

      needroot(0);
      needgroup(0);
		/* device name, debug, verboseopen */
      scgp = open_scsi(pdev_name, errstr, sizeof(errstr), 0, 0);

      if (scgp == NULL) {
		errmsg("%s%sCannot open SCSI driver.\n", errstr, errstr[0]?". ":"");

        fprintf(stderr, "open(%s) in file %s, line %d\n",pdev_name, __FILE__, __LINE__);

        dontneedgroup();
        dontneedroot();
#if defined(sun) || defined(__sun)
        fprintf(stderr, "On SunOS/Solaris make sure you have Joerg Schillings scg SCSI driver installed.\n");
#endif
#if defined (__linux__)
        fprintf(stderr, "Use the script scan_scsi.linux to find out more.\n");
#endif
        fprintf(stderr, "Probably you did not define your SCSI device.\n");
	fprintf(stderr, "You can scan the SCSI bus(es) with 'cdrecord -scanbus'.\n");
        fprintf(stderr, "Set the CDDA_DEVICE environment variable or use the -D option.\n");
        fprintf(stderr, "You can also define the default device in the Makefile.\n");
        exit(1);
      }
	scsi_settimeout(scgp, 100);
	if (scgp) {
		scgp->silent = global.scsi_silent;
		scgp->verbose = global.scsi_verbose;
	}
      dontneedgroup();
      dontneedroot();
      if (global.nsectors > (unsigned) scsi_bufsize(scgp, 100*1024*1024)/CD_FRAMESIZE_RAW)
        global.nsectors = scsi_bufsize(scgp, 100*1024*1024)/CD_FRAMESIZE_RAW;
      if (global.overlap >= global.nsectors)
        global.overlap = global.nsectors-1;

	init_scsibuf(scgp, global.nsectors*CD_FRAMESIZE_RAW);
  } else {
      needgroup(0);
      retval = open(pdev_name,O_RDONLY);
      dontneedgroup();

      if (retval < 0) {
        fprintf(stderr, "while opening %s :", pdev_name);
        perror("");
        exit(1);
      }

      /* Do final security checks here */
      if (fstat(retval, &fstatstruct)) {
        fprintf(stderr, "Could not fstat %s (fd %d): ", pdev_name, retval);
        perror("");
        exit(1);
      }
      Check_interface_for_device( &fstatstruct, pdev_name );

#if defined HAVE_IOCTL_INTERFACE
      /* Watch for race conditions */
      if (have_named_device 
          && (fstatstruct.st_dev != statstruct.st_dev ||
              fstatstruct.st_ino != statstruct.st_ino)) {
         fprintf(stderr,"Race condition attempted in OpenCdRom.  Exiting now.\n");
         exit(1);
      }
#endif
  }
  return retval;
}
#endif /* SIM_CD */

/******************* Simulation interface *****************/
#if	defined SIM_CD
#include "toc.h"
static unsigned long sim_pos=0;

/* read 'SectorBurst' adjacent sectors of audio sectors 
 * to Buffer '*p' beginning at sector 'lSector'
 */
static void ReadCdRom_sim __PR(( SCSI *x, UINT4 *p, unsigned lSector, unsigned SectorBurstVal));
static void ReadCdRom_sim (x, p, lSector, SectorBurstVal )
	SCSI *x;
	UINT4 *p;
	unsigned lSector;
	unsigned SectorBurstVal;
{
  unsigned int loop=0;
  short *q = (short *) p;
  int joffset = 0;

  if (lSector > g_toc[cdtracks].dwStartSector || lSector + SectorBurstVal > g_toc[cdtracks].dwStartSector + 1) {
    fprintf(stderr, "Read request out of bounds: %u - %u (%d - %d allowed)\n",
	lSector, lSector + SectorBurstVal, 0, g_toc[cdtracks].dwStartSector);
  }
#if 0
  /* jitter with a probability of jprob */
  if (random() <= jprob) {
    /* jitter up to jmax samples */
    joffset = random();
  }
#endif

#ifdef DEBUG_SHM
  fprintf(stderr, ", last_b = %p\n", *last_buffer);
#endif
  for (loop = lSector*CD_FRAMESAMPLES + joffset; 
       loop < (lSector+SectorBurstVal)*CD_FRAMESAMPLES + joffset; 
       loop++) {
    *q++ = loop;
    *q++ = ~loop;
  }
#ifdef DEBUG_SHM
  fprintf(stderr, "sim wrote from %p upto %p - 4 (%d), last_b = %p\n",
          p, q, SectorBurstVal*CD_FRAMESAMPLES, *last_buffer);
#endif
  sim_pos = (lSector+SectorBurstVal)*CD_FRAMESAMPLES + joffset; 
}

static int Play_at_sim __PR(( SCSI *x, unsigned int from_sector, unsigned int sectors));
static int Play_at_sim( x, from_sector, sectors)
	SCSI *x;
	unsigned int from_sector;
	unsigned int sectors;
{
  sim_pos = from_sector*CD_FRAMESAMPLES; 
  return 0;
}

static unsigned sim_indices;


/* read the table of contents (toc) via the ioctl interface */
static unsigned ReadToc_sim __PR(( SCSI *x, TOC *toc));
static unsigned ReadToc_sim ( x, toc )
	SCSI *x;
	TOC *toc;
{
    unsigned int scenario;
    int scen[12][3] = { 
      {1,1,500}, 
      {1,2,500}, 
      {1,99,150*99}, 
      {2,1,500}, 
      {2,2,500}, 
      {2,99,150*99},
      {5,1,500}, 
      {5,2,500}, 
      {5,99,150*99}, 
      {99,1,1000}, 
      {99,2,1000}, 
      {99,99,150*99}, 
    };
    unsigned int i;
    unsigned trcks;
#if 0
    fprintf(stderr, "select one of the following TOCs\n"
	    "0 :  1 track  with  1 index\n"
	    "1 :  1 track  with  2 indices\n"
	    "2 :  1 track  with 99 indices\n"
	    "3 :  2 tracks with  1 index each\n"
	    "4 :  2 tracks with  2 indices each\n"
	    "5 :  2 tracks with 99 indices each\n"
	    "6 :  5 tracks with  1 index each\n"
	    "7 :  5 tracks with  2 indices each\n"
	    "8 :  5 tracks with 99 indices each\n"
	    "9 : 99 tracks with  1 index each\n"
	    "10: 99 tracks with  2 indices each\n"
	    "11: 99 tracks with 99 indices each\n"
	    );

    do {
      scanf("%u", &scenario);
    } while (scenario > sizeof(scen)/2/sizeof(int));
#else
    scenario = 6;
#endif
    /* build table of contents */

    trcks = scen[scenario][0] + 1;
    sim_indices = scen[scenario][1];

    for (i = 0; i < trcks; i++) {
        toc[i].bFlags = 0x1b;
        toc[i].bTrack = i + 1;
        toc[i].dwStartSector = i * scen[scenario][2];
    }
    toc[i].bTrack = 0xaa;
    return --trcks;           /* without lead-out */
}


static subq_chnl *ReadSubQ_sim __PR(( SCSI *scgp, unsigned char sq_format, unsigned char track ));
/* request sub-q-channel information. This function may cause confusion
 * for a drive, when called in the sampling process.
 */
static subq_chnl *ReadSubQ_sim ( scgp, sq_format, track )
	SCSI *scgp;
	unsigned char sq_format;
	unsigned char track;
{
    subq_chnl *SQp = (subq_chnl *) (SubQbuffer);
    subq_position *SQPp = (subq_position *) &SQp->data;
    unsigned long sim_pos1;
    unsigned long sim_pos2;

    if ( sq_format != GET_POSITIONDATA ) return NULL;  /* not supported by sim */

    /* simulate CDROMSUBCHNL ioctl */

    /* copy to SubQbuffer */
    SQp->audio_status 	= 0;
    SQp->format 	= 0xff;
    SQp->control_adr	= 0xff;
    sim_pos1 = sim_pos/CD_FRAMESAMPLES;
    sim_pos2 = sim_pos1 % 150;
    SQp->track 		= (sim_pos1 / 5000) + 1;
    SQp->index 		= ((sim_pos1 / 150) % sim_indices) + 1;
    sim_pos1 += 150;
    SQPp->abs_min 	= sim_pos1 / (75*60);
    SQPp->abs_sec 	= (sim_pos1 / 75) % 60;
    SQPp->abs_frame 	= sim_pos1 % 75;
    SQPp->trel_min 	= sim_pos2 / (75*60);
    SQPp->trel_sec 	= (sim_pos2 / 75) % 60;
    SQPp->trel_frame 	= sim_pos2 % 75;

    return (subq_chnl *)(SubQbuffer);
}

static void SelectSpeed_sim __PR(( SCSI *x, unsigned sp));
static void SelectSpeed_sim(x, sp)
	SCSI *x;
	unsigned sp;
{
	PRETEND_TO_USE(x);
	PRETEND_TO_USE(sp);
}

static void trash_cache_sim __PR((UINT4 *p, unsigned lSector, unsigned SectorBurstVal));

static void trash_cache_sim(p, lSector, SectorBurstVal)
	UINT4 *p;
	unsigned lSector;
	unsigned SectorBurstVal;
{
	PRETEND_TO_USE(p);
	PRETEND_TO_USE(lSector);
	PRETEND_TO_USE(SectorBurstVal);
}

static void SetupSimCd __PR((void));

static void SetupSimCd()
{
    EnableCdda = (void (*) __PR((SCSI *, int)))Dummy;
    ReadCdRom = ReadCdRom_sim;
    ReadCdRomData = (void (*) __PR((SCSI *, unsigned char *, unsigned, unsigned ))) ReadCdRom_sim;
    ReadToc = ReadToc_sim;
    ReadTocText = NULL;
    ReadSubQ = ReadSubQ_sim;
    ReadLastAudio = NULL;
    SelectSpeed = SelectSpeed_sim;
    Play_at = Play_at_sim;
    StopPlay = (int (*) __PR((SCSI *)))Dummy;
    trash_cache = trash_cache_sim;
 
}

#endif /* def SIM_CD */

/* perform initialization depending on the interface used. */
void SetupInterface( )
{
#if	defined SIM_CD
    global.nsectors = 75;
    fprintf( stderr, "SIMULATION MODE !!!!!!!!!!!\n");
#else
    /* ensure interface is setup correctly */
    global.cooked_fd = OpenCdRom ( global.dev_name );
#endif

#ifdef  _SC_PAGESIZE
    global.pagesize = sysconf(_SC_PAGESIZE);
#else
    global.pagesize = getpagesize();
#endif

    /* Value of 'nsectors' must be defined here */
    assert(global.nsectors > 0);
    assert(global.buffers > 0);

    global.shmsize = HEADER_SIZE + ENTRY_SIZE_PAGE_AL * global.buffers;

#if	defined (HAVE_FORK_AND_SHAREDMEM)
#if	defined(HAVE_SMMAP) || defined(HAVE_USGSHM) || defined(HAVE_DOSALLOCSHAREDMEM)
    fill_buffer = request_shm_sem(global.shmsize, (unsigned char **)&fill_buffer);
    if (fill_buffer == NULL) {
#else /* have shared memory */
    if (1) {
#endif
	fprintf( stderr, "no shared memory available!\n");
	exit(2);
    }
#else /* do not have fork() and shared memory */
    fill_buffer = malloc(global.shmsize);
    if (fill_buffer == NULL) {
	fprintf( stderr, "no buffer memory available!\n");
	exit(2);
    }
#endif

    if (global.verbose != 0)
   	 fprintf(stderr,
   		 "%u bytes buffer memory requested, %d buffers, %d sectors\n",
   		 global.shmsize, global.buffers, global.nsectors);

    /* initialize pointer into shared memory segment */
    last_buffer = fill_buffer + 1;
    total_segments_read = (unsigned long *) (last_buffer + 1);
    total_segments_written = total_segments_read + 1;
    child_waits = (int *) (total_segments_written + 1);
    parent_waits = child_waits + 1;
    in_lendian = parent_waits + 1;
    *in_lendian = -1;

    set_total_buffers(global.buffers, sem_id);

    /* request one sector for table of contents */
    bufferTOC = (unsigned char *) malloc( CD_FRAMESIZE );      /* assumes sufficient aligned addresses */
    /* SubQchannel buffer */
    SubQbuffer = (subq_chnl *) malloc( 48 );               /* assumes sufficient aligned addresses */
    cmd = (unsigned char *) malloc( 18 );                      /* assumes sufficient aligned addresses */
    if ( !bufferTOC || !SubQbuffer || !cmd ) {
       fprintf( stderr, "Too low on memory. Giving up.\n");
       exit(2);
    }

#if	defined SIM_CD
    SetupSimCd();
#else
    /* if drive is of type scsi, get vendor name */
    if (interface == GENERIC_SCSI) {
        unsigned sector_size;

	SetupSCSI();
        sector_size = get_orig_sectorsize(scgp, &orgmode4, &orgmode10, &orgmode11);
	if (!SCSI_emulated_ATAPI_on(scgp)) {
          if ( sector_size != 2048 && set_sectorsize(scgp, 2048) ) {
	    fprintf( stderr, "Could not change sector size from %d to 2048\n", sector_size );
          }
        } else {
          sector_size = 2048;
        }

	/* get cache setting */

	/* set cache to zero */

#if defined (HAVE_IOCTL_INTERFACE)
    } else {
	SetupCookedIoctl( global.dev_name );
#endif
    }
#endif	/* if def SIM_CD */
}