[OE-core] [PATCH 2/2] useradd.bbclass: retry useradd/groupadd commands to avoid lock race issues

[Scott Garman]

A race condition can occur when adding users and groups to the
passwd and group files, causing errors like the following:

 ERROR: Function 'useradd_sysroot' failed
 Tried to access "/etc/group" but this was locked.

This fix will cause the useradd code to retry the useradd and
groupadd commands up to 10 times (with a 1s sleep in between
attempts) before failing.

This fixes [YOCTO #1794]

Signed-off-by: Scott Garman <scott.a.garman at intel.com>
---
 meta/classes/useradd.bbclass |   36 ++++++++++++++++++++++++++++++++++--
 1 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/meta/classes/useradd.bbclass b/meta/classes/useradd.bbclass
index 7981a68..0bbb371 100644
--- a/meta/classes/useradd.bbclass
+++ b/meta/classes/useradd.bbclass
@@ -45,7 +45,23 @@ if test "x$GROUPADD_PARAM" != "x"; then
 		groupname=`echo "$opts" | awk '{ print $NF }'`
 		group_exists=`grep "^$groupname:" $SYSROOT/etc/group || true`
 		if test "x$group_exists" = "x"; then
-			eval $PSEUDO groupadd  $OPT $opts
+			count=1
+			while true; do
+				eval $PSEUDO groupadd $OPT $opts || true
+				group_exists=`grep "^$groupname:" $SYSROOT/etc/group || true`
+				if test "x$group_exists" = "x"; then
+					# File locking issues can require us to retry the command
+					echo "WARNING: groupadd command did not succeed. Retrying..."
+					sleep 1
+				else
+					break
+				fi
+				count=`expr $count + 1`
+				if test $count = 11; then
+					echo "ERROR: tried running groupadd command 10 times without success, giving up"
+					exit 1
+				fi
+			done		
 		else
 			echo "Note: group $groupname already exists, not re-creating it"
 		fi
@@ -70,7 +86,23 @@ if test "x$USERADD_PARAM" != "x"; then
 		username=`echo "$opts" | awk '{ print $NF }'`
 		user_exists=`grep "^$username:" $SYSROOT/etc/passwd || true`
 		if test "x$user_exists" = "x"; then
-			eval $PSEUDO useradd $OPT $opts
+			count=1
+			while true; do
+				eval $PSEUDO useradd $OPT $opts || true
+				user_exists=`grep "^$username:" $SYSROOT/etc/passwd || true`
+				if test "x$user_exists" = "x"; then
+					# File locking issues can require us to retry the command
+					echo "WARNING: useradd command did not succeed. Retrying..."
+					sleep 1
+				else
+					break
+				fi
+				count=`expr $count + 1`
+				if test $count = 11; then
+					echo "ERROR: tried running useradd command 10 times without success, giving up"
+					exit 1
+				fi
+			done
 		else
 			echo "Note: username $username already exists, not re-creating it"
 		fi
-- 
1.7.5.4