Hopefully fixed a file descriptor resource leak in sg_grab()
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2fa6787d14
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b5bafeb048
@ -12,6 +12,20 @@
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int burn_running = 0;
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/* ts A60813 : wether to use O_EXCL and/or O_NONBLOCK in libburn/sg.c */
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int burn_sg_open_o_excl = 1;
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/* O_NONBLOCK was hardcoded in enumerate_ata() which i hardly use.
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For enumerate_sg() it seems ok.
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So it should stay default mode until enumerate_ata() without O_NONBLOCK
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has been thoroughly tested. */
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int burn_sg_open_o_nonblock = 1;
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/* wether to take a busy drive as an error */
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/* Caution: this is implemented by a rough hack and eventually leads
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to unconditional abort of the process */
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int burn_sg_open_abort_busy = 0;
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int burn_initialize(void)
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{
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if (burn_running)
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@ -31,3 +45,30 @@ void burn_finish(void)
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burn_running = 0;
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}
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/* ts A60813 */
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/** Set parameters for behavior on opening device files. To be called early
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after burn_initialize() and before any bus scan. But not mandatory at all.
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@param exclusive Try to open only devices which are not marked as busy
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and try to mark them busy if opened sucessfully. (O_EXCL)
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There are kernels which simply don't care about O_EXCL.
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Some have it off, some have it on, some are switchable.
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@param blocking Try to wait for drives which do not open immediately but
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also do not return an error as well. (O_NONBLOCK)
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This might stall indefinitely with /dev/hdX hard disks.
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@param abort_on_busy Unconditionally abort process when a non blocking
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exclusive opening attempt indicates a busy drive.
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Use this only after thorough tests with your app.
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Parameter value 1 enables a feature, 0 disables.
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Default is (1,0,0). Have a good reason before you change it.
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*/
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void burn_preset_device_open(int exclusive, int blocking, int abort_on_busy)
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{
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assert(burn_running);
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burn_sg_open_o_excl= !!exclusive;
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burn_sg_open_o_nonblock= !blocking;
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burn_sg_open_abort_busy= !!abort_on_busy;
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}
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@ -442,6 +442,24 @@ void burn_finish(void);
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*/
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void burn_set_verbosity(int level);
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/* ts A60813 */
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/** Set parameters for behavior on opening device files. To be called early
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after burn_initialize() and before any bus scan. But not mandatory at all.
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Parameter value 1 enables a feature, 0 disables.
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Default is (1,0,0). Have a good reason before you change it.
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@param exclusive Try to open only devices which are not marked as busy
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and try to mark them busy if opened sucessfully. (O_EXCL)
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There are kernels which simply don't care about O_EXCL.
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Some have it off, some have it on, some are switchable.
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@param blocking Try to wait for drives which do not open immediately but
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also do not return an error as well. (O_NONBLOCK)
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This might stall indefinitely with /dev/hdX hard disks.
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@param abort_on_busy Unconditionally abort process when a non blocking
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exclusive opening attempt indicates a busy drive.
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Use this only after thorough tests with your app.
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*/
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void burn_preset_device_open(int exclusive, int blocking, int abort_on_busy);
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/** Returns a newly allocated burn_message structure. This message should be
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freed with burn_message_free() when you are finished with it.
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@return A message or NULL when there are no more messages to retrieve.
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@ -28,6 +28,15 @@ static void enumerate_common(char *fname);
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/* ts A51221 */
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int burn_drive_is_banned(char *device_address);
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/* ts A60813 : storage objects are in libburn/init.c
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wether to use O_EXCL
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wether to use O_NOBLOCK with open(2) on devices
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wether to take O_EXCL rejection as fatal error */
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extern int burn_sg_open_o_excl;
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extern int burn_sg_open_o_nonblock;
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extern int burn_sg_open_abort_busy;
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static int sgio_test(int fd)
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{
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unsigned char test_ops[] = { 0, 0, 0, 0, 0, 0 };
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@ -48,6 +57,24 @@ void ata_enumerate(void)
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int i, fd;
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char fname[10];
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/* ts A60813 */
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int open_mode = O_RDWR;
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/* ts A60813
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O_EXCL with block devices is an unpublished feature
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of Linux kernels. Possibly introduced 2002.
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It can only be used if libburn stops opening several
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file descriptor on the same block device.
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See comment in sg_grab() */
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if(burn_sg_open_o_excl)
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open_mode |= O_EXCL;
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/* ts A60813
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O_NONBLOCK was already hardcoded in ata_ but not in sg_.
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There must be some reason for this. So O_NONBLOCK is
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default mode for both now. Disable on own risk. */
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if(burn_sg_open_o_nonblock)
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open_mode |= O_NONBLOCK;
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for (i = 0; i < 26; i++) {
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sprintf(fname, "/dev/hd%c", 'a' + i);
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/* open O_RDWR so we don't think read only drives are
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@ -56,10 +83,23 @@ void ata_enumerate(void)
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/* ts A51221 */
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if (burn_drive_is_banned(fname))
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continue;
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fd = open(fname, O_RDWR | O_NONBLOCK);
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if (fd == -1)
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fd = open(fname, open_mode);
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if (fd == -1) {
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/* <<< debugging
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fprintf(stderr,
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"\nlibburn: experimental: fname= %s , errno= %d\n",
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fname,errno);
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*/
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/* ts A60814 : i see no way to do this more nicely */
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if (errno == EBUSY && burn_sg_open_abort_busy) {
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fprintf(stderr,
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"\nlibburn: FATAL : Application triggered abort on busy drive '%s'\n",
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fname);
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/* <<< maybe one should plainly exit here */
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assert("drive busy" == "non fatal");
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}
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continue;
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}
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/* found a drive */
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ioctl(fd, HDIO_GET_IDENTITY, &tm);
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@ -86,6 +126,34 @@ void sg_enumerate(void)
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int i, fd;
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char fname[10];
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/* ts A60813 */
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int open_mode = O_RDWR;
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/* ts A60813
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O_EXCL with block devices is an unpublished feature
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of Linux kernels. Possibly introduced 2002.
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It can only be used if libburn stops opening several
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file descriptor on the same block device.
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See comment in sg_grab() */
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if(burn_sg_open_o_excl)
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open_mode |= O_EXCL;
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/* ts A60813
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O_NONBLOCK was not hardcoded in sg_ but was in ata_.
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I myself test mainly sg_ and it seems to be ok with
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O_NONBLOCK. So it should stay default mode. */
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if(burn_sg_open_o_nonblock)
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open_mode |= O_NONBLOCK;
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fprintf(stderr,
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"\nlibburn: experimental: o_excl= %d , o_nonblock= %d, abort_on_busy= %d\n",
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burn_sg_open_o_excl,burn_sg_open_o_nonblock,burn_sg_open_abort_busy);
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fprintf(stderr,
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"libburn: experimental: O_EXCL= %d , O_NONBLOCK= %d\n",
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!!(open_mode&O_EXCL),!!(open_mode&O_NONBLOCK));
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/* <<< debugging
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*/
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for (i = 0; i < 32; i++) {
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sprintf(fname, "/dev/sg%d", i);
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/* open RDWR so we don't accidentally think read only drives
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@ -94,10 +162,24 @@ void sg_enumerate(void)
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/* ts A51221 */
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if (burn_drive_is_banned(fname))
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continue;
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fd = open(fname, O_RDWR);
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if (fd == -1)
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continue;
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fd = open(fname, open_mode);
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if (fd == -1) {
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/* <<< debugging
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fprintf(stderr,
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"\n cdrskin: experimental: fname= %s , errno= %d\n",
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fname,errno);
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*/
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/* ts A60814 : i see no way to do this more nicely */
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if (errno == EBUSY && burn_sg_open_abort_busy) {
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fprintf(stderr,
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"\nlibburn: FATAL : Application triggered abort on busy drive '%s'\n",
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fname);
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/* <<< maybe one should plainly exit here */
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assert("drive busy" == "non fatal");
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}
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continue;
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}
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/* found a drive */
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ioctl(fd, SG_GET_SCSI_ID, &sid);
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close(fd);
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@ -167,14 +249,47 @@ static void enumerate_common(char *fname)
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we use the sg reference count to decide whether we can use the
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drive or not.
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if refcount is not one, drive is open somewhere else.
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ts A60813: this test is too late. O_EXCL is the stronger solution.
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After all the test was diabled already in icculus.org/burn CVS.
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*/
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int sg_grab(struct burn_drive *d)
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{
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int fd, count;
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fd = open(d->devname, O_RDWR | O_NONBLOCK);
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/* ts A60813 */
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int open_mode = O_RDWR;
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/* ts A60813
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O_EXCL with block devices is an unpublished feature
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of Linux kernels. Possibly introduced 2002.
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It can only be used if libburn stops opening several
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file descriptor on the same block device.
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See comment below */
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if(burn_sg_open_o_excl)
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open_mode |= O_EXCL;
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/* ts A60813
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O_NONBLOCK was hardcoded here. So it should stay default mode. */
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if(burn_sg_open_o_nonblock)
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open_mode |= O_NONBLOCK;
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/* ts A60813
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After enumeration the drive fd is probably still open.
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-1337 is the initial value of burn_drive.fd and the value after
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relase of drive. Unclear why not the official error return
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value -1 of open(2) war used. */
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if(d->fd == -1337)
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fd = open(d->devname, open_mode);
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else
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fd= d->fd;
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assert(fd != -1337);
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if (-1 != fd) {
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/* ts A60814:
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according to my experiments this test would work now ! */
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/* er = ioctl(fd, SG_GET_ACCESS_COUNT, &count);*/
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count = 1;
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if (1 == count) {
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