Date: Tue, 20 Jan 2009 20:10:02 GMT From: Jaakko Heinonen <jh@saunalahti.fi> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/123693: [patch] burncd(8): workaround for busy cd-writer while ejecting Message-ID: <200901202010.n0KKA2FU032907@freefall.freebsd.org>
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The following reply was made to PR bin/123693; it has been noted by GNATS.
From: Jaakko Heinonen <jh@saunalahti.fi>
To: Alexander Best <alexbestms@math.uni-muenster.de>,
"Carlos A. M. dos Santos" <unixmania@gmail.com>
Cc: bug-followup@FreeBSD.org
Subject: Re: bin/123693: [patch] burncd(8): workaround for busy cd-writer
while ejecting
Date: Tue, 20 Jan 2009 22:00:39 +0200
Hi,
A similar problem exists if you combine blank and data commands:
# burncd -s max blank data image.iso
blanking CD - 100 % done
burncd: ioctl(CDIOCSTART): Device busy
Thus in my opinion a more generic solution is desired. Possibly the
correct solution would be to issue ATAPI_TEST_UNIT_READY command until
the drive reports a ready state. This could be done in kernel or in user
space.
If done in user space there's the CDIOCRESET ioctl which issues the
ATAPI_TEST_UNIT_READY command. Here is a patch which implements
wait_for_ready() function in burncd using the CDIOCRESET ioctl:
--- patch begins here ---
Index: usr.sbin/burncd/burncd.c
===================================================================
--- usr.sbin/burncd/burncd.c (revision 187153)
+++ usr.sbin/burncd/burncd.c (working copy)
@@ -65,6 +65,7 @@ void add_track(char *, int, int, int);
void do_DAO(int fd, int, int);
void do_TAO(int fd, int, int, int);
void do_format(int, int, char *);
+void wait_for_ready(int);
int write_file(int fd, struct track_info *);
int roundup_blocks(struct track_info *);
void cue_ent(struct cdr_cue_entry *, int, int, int, int, int, int, int);
@@ -219,6 +220,7 @@ main(int argc, char **argv)
break;
last = pct;
}
+ wait_for_ready(fd);
if (!quiet)
printf("\n");
continue;
@@ -323,6 +325,8 @@ main(int argc, char **argv)
err(EX_IOERR, "ioctl(CDRIOCSETBLOCKSIZE)");
}
+ wait_for_ready(fd);
+
if (eject)
if (ioctl(fd, CDIOCEJECT) < 0)
err(EX_IOERR, "ioctl(CDIOCEJECT)");
@@ -600,6 +604,27 @@ do_format(int the_fd, int force, char *t
fprintf(stderr, "\n");
}
+void
+wait_for_ready(int fd)
+{
+ int timeout = 10 * 1000;
+
+ while (timeout > 0) {
+ /*
+ * CDIOCRESET issues ATAPI_TEST_UNIT_READY command.
+ */
+ if (ioctl(fd, CDIOCRESET) == 0)
+ return;
+ else if (errno != EBUSY)
+ err(EX_IOERR, "ioctl(CDIOCRESET)");
+
+ usleep(500 * 1000);
+ timeout -= 500;
+ }
+
+ errx(EX_IOERR, "timed out while waiting for the drive to become ready");
+}
+
int
write_file(int fd, struct track_info *track_info)
{
--- patch ends here ---
There is apparently a bogus privilege check in atapi-cd.c for CDIOCRESET
ioctl. It prevents CDIOCRESET to work for non-root users. (Remember that
ioctls are restricted with device permissions.) So this change is needed
for CDIOCRESET to work for non-root users:
--- patch begins here ---
Index: sys/dev/ata/atapi-cd.c
===================================================================
--- sys/dev/ata/atapi-cd.c (revision 187157)
+++ sys/dev/ata/atapi-cd.c (working copy)
@@ -255,13 +255,7 @@ acd_geom_ioctl(struct g_provider *pp, u_
cdp->flags |= F_LOCKED;
break;
- /*
- * XXXRW: Why does this require privilege?
- */
case CDIOCRESET:
- error = priv_check(td, PRIV_DRIVER);
- if (error)
- break;
error = acd_test_ready(dev);
break;
--- patch ends here ---
Note that if you intend to test these patches on stable/7 (or older) you
need to backport r187105 (a fix to ata-queue.c) from head. Otherwise the
CDIOCRESET ioctl doesn't correctly report the busy state. (See
http://www.freebsd.org/cgi/query-pr.cgi?pr=95979 for more information.)
On 2009-01-10, Alexander Best wrote:
> i adjusted your patch a bit. now the loop will break if the return value is
> EIO e.g.
> + while ((error = ioctl(fd, CDIOCEJECT)) < 0 && retries-- > 0) {
> + if (error != EBUSY)
> + err(EX_IOERR, "ioctl(CDIOCEJECT)");
Alexander: you can't test a value returned from ioctl(2) with EBUSY. You
should use errno instead of error.
--
Jaakko
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