On 07/06/2013 06:27 PM, Martin Jansa wrote:
On Wed, Jul 03, 2013 at 12:48:12PM +0800, qi.c...@windriver.com wrote:
From: Chen Qi <qi.c...@windriver.com>

We now can have a 'one-binary' version of busybox, or 'two-binary'
version of busybox, controlled by the 'BUSYBOX_SPLIT_SUID' variable.
This makes on-target upgrade a problem, as we have to support the
following four upgrading paths.

For convenience, in the following context, A is used to denote a
'two-binary' version of busybox while B is used to denote a 'one-binary'
version of busybox.

A --(upgrade)--> B
B --(upgrade)--> A
A --(upgrade)--> A
B --(upgrade)--> B

This patch makes effort to support the above four situations.
Thanks for looking into it (it's more complicated then I've first
expected) and it looks like there is more issues probably caused
by applet path moved in latest busybox upgrade (but ip looks weird) :/

update-alternatives: Error: cannot register alternative addgroup to
/usr/sbin/addgroup since it is already registered to /bin/addgroup
update-alternatives: Error: cannot register alternative adduser to
/usr/sbin/adduser since it is already registered to /bin/adduser

update-alternatives: Error: cannot register alternative delgroup to
/usr/sbin/delgroup since it is already registered to /bin/delgroup
update-alternatives: Error: cannot register alternative deluser to
/usr/sbin/deluser since it is already registered to /bin/deluser

update-alternatives: Error: cannot register alternative ip to /sbin/ip
since it is already registered to /bin/ip

SHR root@gjama ~ $ cat /var/lib/opkg/alternatives/ip
/bin/ip
busybox 50
/bin/busybox 50
/bin/busybox.nosuid 50
SHR root@gjama ~ $ cat /var/lib/opkg/alternatives/adduser
/bin/adduser
/bin/busybox.nosuid 50
SHR root@gjama ~ $ cat /var/lib/opkg/alternatives/addgroup
/bin/addgroup
/bin/busybox.nosuid 50
SHR root@gjama ~ $ cat /var/lib/opkg/alternatives/delgroup
/bin/delgroup
/bin/busybox.nosuid 50
SHR root@gjama ~ $ cat /var/lib/opkg/alternatives/deluser
/bin/deluser
/bin/busybox.nosuid 50
Hi Martin,

The problem roots in opkg's update-alternatives.
opkg's update-alternatives cannot handle following situations.
/bin/<cmd> --> /bin/<cmd>.<pkgA>
/usr/bin/<cmd> --> /usr/bin/<cmd>.<pkgB>.
[Let's denote this situation as situationA, we have different links and different targets in situationA.]

It has a simple assumption in its design, that is, the links for the same command should be the same.

In case of our busybox upgrade, we have:
/bin/deluser --> /bin/busybox.nosuid
/usr/sbin/deluser --> /bin/busybox.nosuid
[Let's denote this situation as situationB, we have different links but the same target in situationB.]

The links are different, /bin/deluser and /usr/sbin/deluser, so opkg's update-alternatives rendered an error while registering the alternative.

According to its assumption, opkg's update-alternatives should not support situationA and situationB. But I think it should at least be able to deal with situationB. Because it's not unusual in Yocto/OE to create symlinks via update-alternatives and situationB might indicate an on-device upgrade. I've just made a patch to support this situationB. I'm still doing some tests on this patch. Please see attachment for more details.

Any thoughts on this problem?

Best Regards,
Chen Qi
[YOCTO #4802]

Signed-off-by: Chen Qi <qi.c...@windriver.com>
---
  meta/recipes-core/busybox/busybox.inc |   48 +++++++++++++++++++++++++++++++++
  1 file changed, 48 insertions(+)

diff --git a/meta/recipes-core/busybox/busybox.inc 
b/meta/recipes-core/busybox/busybox.inc
index 8567d64..acd2bfb 100644
--- a/meta/recipes-core/busybox/busybox.inc
+++ b/meta/recipes-core/busybox/busybox.inc
@@ -190,6 +190,10 @@ do_install () {
                        install -m 0644 ${S}/busybox.links.suid 
${D}${sysconfdir}
                        install -m 0644 ${S}/busybox.links.nosuid 
${D}${sysconfdir}
                        ln -sf busybox.nosuid ${D}${base_bindir}/sh
+                       # Keep a default busybox for people who want to invoke 
busybox directly.
+                       # This is also useful for the on device upgrade. 
Because we want
+                       # to use the busybox command in postinst.
+                       ln -sf busybox.nosuid ${D}${base_bindir}/busybox
                else
                        if grep -q "CONFIG_FEATURE_SUID=y" ${B}/.config; then
                                install -m 4755 ${B}/busybox ${D}${base_bindir}
@@ -198,6 +202,12 @@ do_install () {
                        fi
                        install -m 0644 ${S}/busybox.links ${D}${sysconfdir}
                        ln -sf busybox ${D}${base_bindir}/sh
+                       # We make this symlink here to eliminate the error when 
upgrading together
+                       # with busybox-syslog. Without this symlink, the opkg 
may think of the
+                       # busybox.nosuid as obsolete and remove it, resulting 
in dead links like
+                       # /bin/sed -> /bin/busybox.nosuid. This will make 
upgrading busybox-syslog fail.
+                       # This symlink will be safely deleted in postinst, thus 
no negative effect.
+                       ln -sf busybox ${D}${base_bindir}/busybox.nosuid
                fi
        else
                install -d ${D}${base_bindir} ${D}${base_sbindir}
@@ -306,6 +316,44 @@ python do_package_prepend () {
          set_alternative_vars("/etc/busybox.links.suid", "/bin/busybox.suid")
  }
+pkg_postinst_${PN} () {
+       # This part of code is dedicated to the on target upgrade problem.
+       # It's known that if we don't make appropriate symlinks before 
update-alternatives calls,
+       # there will be errors indicating missing commands such as 'sed'.
+       # These symlinks will later be updated by update-alternatives calls.
+       test -n 2 > /dev/null || alias test='busybox test'
+       if test "x$D" = "x"; then
+               # Remove busybox.nosuid if it's a symlink, because this 
situation indicates
+               # that we're installing or upgrading to a one-binary busybox.
+               if test -h /bin/busybox.nosuid; then
+                       rm -f /bin/busybox.nosuid
+               fi
+               for suffix in "" ".nosuid" ".suid"; do
+                       if test -e /etc/busybox.links$suffix; then
+                               while read link; do
+                                       if test ! -e "$link"; then
+                                               case "$link" in
+                                                       /*/*/*)
+                                                               
to="../../bin/busybox$suffix"
+                                                               ;;
+                                                       /bin/*)
+                                                               
to="busybox$suffix"
+                                                               ;;
+                                                       /*/*)
+                                                               
to="../bin/busybox$suffix"
+                                                               ;;
+                                               esac
+                                               # we can use busybox here 
because even if we are using splitted busybox
+                                               # we've made a symlink from 
/bin/busybox to /bin/busybox.nosuid.
+                                               busybox rm -f $link
+                                               busybox ln -s $to $link
+                                       fi
+                               done < /etc/busybox.links$suffix
+                       fi
+               done
+       fi
+}
+
  pkg_prerm_${PN} () {
        # This is so you can make busybox commit suicide - removing busybox 
with no other packages
        # providing its files, this will make update-alternatives work, but the 
update-rc.d part
--
1.7.9.5

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>From 02f2bba4d3d92daf870f86ae02a206af51a53b1d Mon Sep 17 00:00:00 2001
From: Chen Qi <qi.c...@windriver.com>
Date: Mon, 8 Jul 2013 04:13:14 -0400
Subject: [PATCH] opkg: fix update-alternatives to handle on-device upgrade

---
 ...ate-alternatives-fix-register_alt-process.patch |   61 ++++++++++++++++++++
 meta/recipes-devtools/opkg/opkg_svn.bb             |    3 +-
 2 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 meta/recipes-devtools/opkg/opkg/0001-update-alternatives-fix-register_alt-process.patch

diff --git a/meta/recipes-devtools/opkg/opkg/0001-update-alternatives-fix-register_alt-process.patch b/meta/recipes-devtools/opkg/opkg/0001-update-alternatives-fix-register_alt-process.patch
new file mode 100644
index 0000000..2903dfd
--- /dev/null
+++ b/meta/recipes-devtools/opkg/opkg/0001-update-alternatives-fix-register_alt-process.patch
@@ -0,0 +1,61 @@
+From da31772150f764ee2cb11de38a4e7b6278105423 Mon Sep 17 00:00:00 2001
+From: Chen Qi <qi.c...@windriver.com>
+Date: Mon, 8 Jul 2013 03:32:42 -0400
+Subject: [PATCH] update-alternatives: fix register_alt process
+
+---
+ utils/update-alternatives.in |   24 +++++++++++++++++++++---
+ 1 file changed, 21 insertions(+), 3 deletions(-)
+
+diff --git a/utils/update-alternatives.in b/utils/update-alternatives.in
+index 2a6f6cc..3d592b2 100644
+--- a/utils/update-alternatives.in
++++ b/utils/update-alternatives.in
+@@ -46,6 +46,7 @@ register_alt() {
+ 	[ $# -lt 2 ] && return 1
+ 	local name="$1"
+ 	local link="$2"
++	local path="$3"
+ 
+ 	if [ ! -d $ad ]; then
+ 		mkdir -p $ad
+@@ -54,8 +55,25 @@ register_alt() {
+ 	if [ -e "$ad/$name" ]; then
+ 		local olink=`head -n 1 $ad/$name`
+ 		if [ "$link" != "$olink" ]; then
+-			echo "update-alternatives: Error: cannot register alternative $name to $link since it is already registered to $olink" >&2
+-			return 1
++			local target_conflict="no"
++			if [ `wc -l $ad/$name | cut -d' ' -f1` != "2" ]; then
++				target_conflict="yes"
++			elif [ `tail -n 1 $ad/$name | cut -d' ' -f1` != "$path" ]; then
++				target_conflict="yes"
++			else
++				target_conflict="no"
++			fi
++			if [ "$target_conflict" = "yes" ]; then
++				echo "update-alternatives: Error: cannot register alternative $name to $link since it is already registered to $olink and there are more than one target" >&2
++				return 1
++			else
++				# Only one target for name and the link has changed.
++				echo "$link" > $ad/$name.new
++				tail -n 1 $ad/$name >> $ad/$name.new
++				mv $ad/$name.new $ad/$name
++				ln -snf $path $link
++				rm -f $olink
++			fi
+ 		fi
+ 	else
+ 		echo "$link" > "$ad/$name"
+@@ -137,7 +155,7 @@ do_install() {
+ 	# This is a bad hack, but I haven't thought of a cleaner solution yet...
+ 	[ -n "$OPKG_OFFLINE_ROOT" ] && path=`echo $path | sed "s|^$OPKG_OFFLINE_ROOT/*|/|"`
+ 
+-	register_alt $name $link
++	register_alt $name $link $path
+ 	add_alt $name $path $priority
+ 	find_best_alt $name
+ }
+-- 
+1.7.9.5
+
diff --git a/meta/recipes-devtools/opkg/opkg_svn.bb b/meta/recipes-devtools/opkg/opkg_svn.bb
index 9f3512d..6ba6195 100644
--- a/meta/recipes-devtools/opkg/opkg_svn.bb
+++ b/meta/recipes-devtools/opkg/opkg_svn.bb
@@ -2,7 +2,8 @@ require opkg.inc
 
 SRC_URI = "svn://opkg.googlecode.com/svn;module=trunk;protocol=http \
            file://obsolete_automake_macros.patch \
-	   file://0001-Fix-libopkg-header-installation.patch \
+           file://0001-Fix-libopkg-header-installation.patch \
+           file://0001-update-alternatives-fix-register_alt-process.patch \
 "
 
 S = "${WORKDIR}/trunk"
-- 
1.7.9.5

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