main/util-linux: backport libblkid cdrom probe patch

ref #5697

main/util-linux/APKBUILD

@@ -8,7 +8,7 @@ case $pkgver in
 	*.*) _v=$pkgver;;
 esac
 
-pkgrel=2
+pkgrel=3
 pkgdesc="Random collection of Linux utilities"
 url="http://git.kernel.org/cgit/utils/util-linux/util-linux.git"
 arch="all"
@@ -19,6 +19,7 @@ makedepends="zlib-dev sed ncurses-dev tar autoconf automake libtool python-dev l
 install=
 options="suid"
 source="http://www.kernel.org/pub/linux/utils/util-linux/v${_v}/util-linux-$pkgver.tar.xz
+	libblkid-reduce-probing-area-for-crazy-CDROMs.patch
 	ttydefaults.h
 	"
 subpackages="$pkgname-doc $pkgname-dev libuuid libblkid libmount
@@ -152,8 +153,11 @@ _py() {
 }
 
 md5sums="e534e6ccc49107e5d31c329af798ef7d  util-linux-2.28.tar.xz
+ee12cce6423e6f7ea4c9c438989e77d7  libblkid-reduce-probing-area-for-crazy-CDROMs.patch
 6196f1ce853dfaf717569c1e35555d6d  ttydefaults.h"
 sha256sums="395847e2a18a2c317170f238892751e73a57104565344f8644090c8b091014bb  util-linux-2.28.tar.xz
+12b6434a229d08c81f45735cac50e9003908f3ad974c59cec93ddf57700077f3  libblkid-reduce-probing-area-for-crazy-CDROMs.patch
 46faf1198bd884d12c5d45019a5fec8dfdefeae6721d8c9f3da89921acdb2a6d  ttydefaults.h"
 sha512sums="a1f911bdfda5985de87105d39501e501a5f9ec0fe6a433e3f2fed9a80e104342bb4a7e0e6dc9b7d677d5429249f05b343cb5370b0ea0e068dc889699d4ec1f8a  util-linux-2.28.tar.xz
+ec27d4227f7e0f08198ecf00f4c7da379ed588eb05835c318322bec26841868e51337c5710706237a7a3358aa0db6d4514c8f2444d02b2bd800f1c7f9e9570c2  libblkid-reduce-probing-area-for-crazy-CDROMs.patch
 876bb9041eca1b2cca1e9aac898f282db576f7860aba690a95c0ac629d7c5b2cdeccba504dda87ff55c2a10b67165985ce16ca41a0694a267507e1e0cafd46d9  ttydefaults.h"

main/util-linux/libblkid-reduce-probing-area-for-crazy-CDROMs.patch

+From bfebe74e3babe8c188a51269acc2673f1aea283f Mon Sep 17 00:00:00 2001
+From: Karel Zak <kzak@redhat.com>
+Date: Tue, 19 Apr 2016 12:39:05 +0200
+Subject: [PATCH] libblkid: reduce probing area for crazy CDROMs
+
+Linux kernel reports devices greater than area readable by read(2).
+The readable area is usually 2-3 CD blocks smaller (CD block is
+2048-bytes) than size returned by BLKGETSIZE. This patch checks for
+this issues to avoid I/O errors in probing functions.
+
+Reported-by: Thomas Schmitt <scdbackup@gmx.net>
+Signed-off-by: Karel Zak <kzak@redhat.com>
+---
+ libblkid/src/probe.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++-
+ 1 file changed, 49 insertions(+), 1 deletion(-)
+
+diff --git a/libblkid/src/probe.c b/libblkid/src/probe.c
+index 0c8625c..0455c37 100644
+--- a/libblkid/src/probe.c
++++ b/libblkid/src/probe.c
+@@ -752,6 +752,51 @@ int blkid_probe_is_cdrom(blkid_probe pr)
+ 	return pr && (pr->flags & BLKID_FL_CDROM_DEV);
+ }
+ 
++static int is_sector_readable(int fd, uint64_t sector)
++{
++	char buf[512];
++	ssize_t sz;
++
++	if (blkid_llseek(fd, sector * 512, SEEK_SET) < 0)
++		goto failed;
++
++	sz = read(fd, buf, sizeof(buf));
++	if (sz != (ssize_t) sizeof(buf))
++		goto failed;
++
++	return 1;
++failed:
++	DBG(LOWPROBE, ul_debug("CDROM: read sector %ju failed %m", sector));
++	errno = 0;
++	return 0;
++}
++
++/*
++ * Linux kernel reports (BLKGETSIZE) cdrom device size greater than area
++ * readable by read(2). We have to reduce the probing area to avoid unwanted
++ * I/O errors in probing functions. It seems that unreadable are always last 2
++ * or 3 CD blocks (CD block size is 2048 bytes, it means 12 in 512-byte
++ * sectors).
++ */
++static void cdrom_size_correction(blkid_probe pr)
++{
++	uint64_t n, nsectors = pr->size >> 9;
++
++	for (n = nsectors - 12; n < nsectors; n++) {
++		if (!is_sector_readable(pr->fd, n))
++			goto failed;
++	}
++
++	DBG(LOWPROBE, ul_debug("CDROM: full size available"));
++	return;
++failed:
++	/* 'n' is the failed sector, reduce device size to n-1; */
++	DBG(LOWPROBE, ul_debug("CDROM: reduce size from %ju to %ju.",
++				(uintmax_t) pr->size,
++				(uintmax_t) (n - 1) << 9));
++	pr->size = n << 9;
++}
++
+ /**
+  * blkid_probe_set_device:
+  * @pr: probe
+@@ -844,8 +889,11 @@ int blkid_probe_set_device(blkid_probe pr, int fd,
+ 	else if (S_ISBLK(sb.st_mode) &&
+ 	    !blkid_probe_is_tiny(pr) &&
+ 	    blkid_probe_is_wholedisk(pr) &&
+-	    ioctl(fd, CDROM_GET_CAPABILITY, NULL) >= 0)
++	    ioctl(fd, CDROM_GET_CAPABILITY, NULL) >= 0) {
++
+ 		pr->flags |= BLKID_FL_CDROM_DEV;
++		cdrom_size_correction(pr);
++	}
+ #endif
+ 
+ 	DBG(LOWPROBE, ul_debug("ready for low-probing, offset=%"PRIu64", size=%"PRIu64"",