runqemu-gen-tapdevs: Refactoring

The changes are mostly about early exit which causes indentation changes;
check with `git diff -w`. Another change is the check for ip by simply
calling it and deciding upon the exit code, if it's fine or not.

(From OE-Core rev: 351577761d0712a005eda9dde9215558ca9a1fe9)

Signed-off-by: Jörg Sommer <joerg.sommer@navimatix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 36 insertions, 39 deletions

diff --git a/scripts/runqemu-gen-tapdevs b/scripts/runqemu-gen-tapdevs
index a6ee4517da..f2d6cc39c2 100755
--- a/scripts/runqemu-gen-tapdevs
+++ b/scripts/runqemu-gen-tapdevs
@@ -44,6 +44,12 @@ GID=$2
 COUNT=$3
 STAGING_BINDIR_NATIVE=$4
 
+# check if COUNT is a number and >= 0
+if ! [ $COUNT -ge 0 ]; then
+        echo "Error: Incorrect count: $COUNT"
+        exit 1
+fi
+
 TUNCTL=$STAGING_BINDIR_NATIVE/tunctl
 if [[ ! -x "$TUNCTL" || -d "$TUNCTL" ]]; then
         echo "Error: $TUNCTL is not an executable"
@@ -62,48 +68,39 @@ if [ ! -x "$RUNQEMU_IFUP" ]; then
         exit 1
 fi
 
-IFCONFIG=`which ip 2> /dev/null`
-if [ -z "$IFCONFIG" ]; then
-        # Is it ever anywhere else?
-        IFCONFIG=/sbin/ip
-fi
-if [ ! -x "$IFCONFIG" ]; then
-       echo "$IFCONFIG cannot be executed"
-       exit 1
+if ! interfaces=`ip link` 2>/dev/null; then
+        echo "Failed to call 'ip link'" >&2
+        exit 1
 fi
 
-if [ $COUNT -ge 0 ]; then
-        # Ensure we start with a clean slate
-        for tap in `$IFCONFIG link | grep tap | awk '{ print \$2 }' | sed s/://`; do
-                echo "Note: Destroying pre-existing tap interface $tap..."
-                $TUNCTL -d $tap
-        done
-        rm -f /etc/runqemu-nosudo
-else
-        echo "Error: Incorrect count: $COUNT"
-        exit 1
+# Ensure we start with a clean slate
+for tap in `echo "$interfaces" | sed '/^[0-9]\+: \(docker[0-9]\+\):.*/!d; s//\1/'`; do
+        echo "Note: Destroying pre-existing tap interface $tap..."
+        $TUNCTL -d $tap
+done
+rm -f /etc/runqemu-nosudo
+
+if [ $COUNT -eq 0 ]; then
+        exit 0
 fi
 
-if [ $COUNT -gt 0 ]; then
-        echo "Creating $COUNT tap devices for UID: $TUID GID: $GID..."
-        for ((index=0; index < $COUNT; index++)); do
-                echo "Creating tap$index"
-                ifup=`$RUNQEMU_IFUP $TUID $GID $STAGING_BINDIR_NATIVE 2>&1`
-                if [ $? -ne 0 ]; then
-                        echo "Error running tunctl: $ifup"
-                        exit 1
-                fi
-        done
+echo "Creating $COUNT tap devices for UID: $TUID GID: $GID..."
+for ((index=0; index < $COUNT; index++)); do
+        echo "Creating tap$index"
+        if ! ifup=`$RUNQEMU_IFUP $TUID $GID $STAGING_BINDIR_NATIVE 2>&1`; then
+                echo "Error running tunctl: $ifup"
+                exit 1
+        fi
+done
 
-        echo "Note: For systems running NetworkManager, it's recommended"
-        echo "Note: that the tap devices be set as unmanaged in the"
-        echo "Note: NetworkManager.conf file. Add the following lines to"
-        echo "Note: /etc/NetworkManager/NetworkManager.conf"
-        echo "[keyfile]"
-        echo "unmanaged-devices=interface-name:tap*"
+echo "Note: For systems running NetworkManager, it's recommended"
+echo "Note: that the tap devices be set as unmanaged in the"
+echo "Note: NetworkManager.conf file. Add the following lines to"
+echo "Note: /etc/NetworkManager/NetworkManager.conf"
+echo "[keyfile]"
+echo "unmanaged-devices=interface-name:tap*"
 
-        # The runqemu script will check for this file, and if it exists,
-        # will use the existing bank of tap devices without creating
-        # additional ones via sudo.
-        touch /etc/runqemu-nosudo
-fi
+# The runqemu script will check for this file, and if it exists,
+# will use the existing bank of tap devices without creating
+# additional ones via sudo.
+touch /etc/runqemu-nosudo