libnss-mdns: avoid race condition in postinst

Writing to "/tmp/nsswitch.conf" leads to a race condition if two
copies of the postinst are running simultaneously.  Fix this by
modifying /etc/nsswitch.conf in place using sed -i.  Also make the
same change to the prerm for consistency although the race will not
occur here in practice.

(From OE-Core rev: 689884653938b98899fb3ba791221fdbe2f40e7f)

Signed-off-by: Phil Blundell <philb@gnu.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 3 insertions, 5 deletions

diff --git a/meta/recipes-connectivity/libnss-mdns/libnss-mdns_0.10.bb b/meta/recipes-connectivity/libnss-mdns/libnss-mdns_0.10.bb
index 5f614f86a2..87707142d5 100644
--- a/meta/recipes-connectivity/libnss-mdns/libnss-mdns_0.10.bb
+++ b/meta/recipes-connectivity/libnss-mdns/libnss-mdns_0.10.bb
@@ -7,7 +7,7 @@ LIC_FILES_CHKSUM = "file://LICENSE;md5=2d5025d4aa3495befef8f17206a5b0a1"
 
 DEPENDS = "avahi"
 RDEPENDS_${PN} = "avahi-daemon"
-PR = "r3"
+PR = "r4"
 
 SRC_URI = "http://0pointer.de/lennart/projects/nss-mdns/nss-mdns-${PV}.tar.gz"
 
@@ -26,14 +26,12 @@ EXTRA_OECONF = "--libdir=${base_libdir} --disable-lynx --enable-avahi"
 # TODO: pattern based configuration update
 pkg_postinst_${PN} () {
         cat $D/etc/nsswitch.conf | grep "hosts:\s*files dns$" > /dev/null && {
-                cat $D/etc/nsswitch.conf | sed 's/hosts:\s*files dns/& mdns4/' > /tmp/nsswitch.conf
-                mv /tmp/nsswitch.conf $D/etc/nsswitch.conf
+                sed -i 's/hosts:\s*files dns/& mdns4/' $D/etc/nsswitch.conf
         }
 }
 
 pkg_prerm_${PN} () {
         cat /etc/nsswitch.conf | grep "hosts:\s*files dns mdns4$" > /dev/null && {
-                cat /etc/nsswitch.conf | sed 's/\(hosts:\s*files dns\) mdns4*/\1/' > /tmp/nsswitch.conf
-                mv /tmp/nsswitch.conf /etc/nsswitch.conf
+                sed -i 's/\(hosts:\s*files dns\) mdns4*/\1/' /etc/nsswitch.conf
         }
 }