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cdrom_id: Try reading the medium if all MMC commands fail

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Reportedly, some "when I'm grown up I want to be a CD drive" fake USB CD sticks
like the IronKey neither support the SCSI "GET CONFIGURATION" nor the older
(pre-MMC2) "READ DISC INFORMATION" command. In that case, check if we can read
data from the drive, and assume that we have a CD-ROM medium if it succeeds.
This commit is contained in:
Martin Pitt 2010-10-05 14:34:55 +02:00
parent 0bd77e2acd
commit ea88774a92
1 changed files with 30 additions and 2 deletions
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32
extras/cdrom_id/cdrom_id.c
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@ -350,6 +350,34 @@ static int feature_profiles(struct udev *udev, const unsigned char *profiles, si
return 0;
}
static int cd_profiles_broken_mmc(struct udev *udev, int fd)
{
struct scsi_cmd sc;
unsigned char buffer[16 * 2048];
int err;
/* we land here if both the standard and the old MMC commands failed;
* this might happen on broken wanna-be-CD USB drives like the IronKey.
* As a last resort, try to read data to see whether it has a medium.
*/
scsi_cmd_init(udev, &sc, buffer, sizeof(buffer));
scsi_cmd_set(udev, &sc, 0, 0x28);
scsi_cmd_set(udev, &sc, 5, 0);
scsi_cmd_set(udev, &sc, 8, 16);
scsi_cmd_set(udev, &sc, 9, 0);
err = scsi_cmd_run(udev, &sc, fd, buffer, sizeof(buffer));
if ((err != 0)) {
info(udev, "READ DATA failed, assuming no medium\n");
return -1;
}
/* that's all we can claim if we can read data */
info(udev, "READ DATA succeeded, assuming CD-ROM medium\n");
cd_media = 1;
cd_media_cd_rom = 1;
return 0;
}
static int cd_profiles_old_mmc(struct udev *udev, int fd)
{
struct scsi_cmd sc;
@ -364,8 +392,8 @@ static int cd_profiles_old_mmc(struct udev *udev, int fd)
err = scsi_cmd_run(udev, &sc, fd, header, sizeof(header));
if ((err != 0)) {
info_scsi_cmd_err(udev, "READ DISC INFORMATION", err);
info(udev, "no current profile, assuming no media\n");
return -1;
info(udev, "no current profile, probing readability of medium\n");
return cd_profiles_broken_mmc(udev, fd);
};
cd_media = 1;