ifup: extend ifup/ifdown to be smarter about NetworkManager profiles

Now that NetworkManager on Fedora 33 and RHEL 9 no longer writes
ifcfg-rh files by default ([1]), ifup/ifdown became less useful.

Possibly users shouldn't use it and it would be fine that new-style profiles
(keyfile) no longer work with these commands. But this is deemed as too
disruptive for users.

Note that our previous ifup/ifdown compat scripts only honored the argument
to be part of the ifcfg filename. That was not what initscripts were doing,
which called `need_config()` function that searched also the contents of
the files. With this extension, ifup/ifdown gets smarter too, to better
guess what the user might have wanted.

Extend the script by making it smarter, and to work with connection profile
names.

With this extension we further solidify ifup/ifdown as part of NetworkManager
command line API. That is problematic, because these tools pollute the
$PATH, by not having a clear NM-specific name. Also, these scripts
should only exist on Fedora/RHEL, which makes their usage non-portable
to other distros.
Also, other distros already ship different tools with name ifup/ifdown.
Extending the use of these scripts is thus undesirable, as it furthers
distro-specific commands.

Still, these arguments seem to not hold and users need to be "helped".
As Fedora users cannot be expected to unlearn "ifup" today, there is no
reason to assume they could in a few years. This likely means we will
never get rid of these scripts.

Also, if we truly would make ifup/ifdown part of NetworkManager, then a better
implementation would be that nmcli honors being called with these names.
That is not done, because nmcli's implementation currently is not as
nice to make that extension trivial (as it should be). It also would
mean to embrace ifup/ifdown officially. A shell script works well enough
as a hack.

[1] https://fedoraproject.org/wiki/Changes/NetworkManager_keyfile_instead_of_ifcfg_rh

https://bugzilla.redhat.com/show_bug.cgi?id=1954607

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/936
(cherry picked from commit 30e7400528)

src/core/settings/plugins/ifcfg-rh/nm-ifdown

@@ -1,3 +1,44 @@
-#!/bin/sh
-nmcli connection load "/etc/sysconfig/network-scripts/ifcfg-$1" &&
-exec nmcli connection down filename "/etc/sysconfig/network-scripts/ifcfg-$1"
+#!/bin/bash
+
+CONFIG="$1"
+
+if [ -z "${CONFIG}" ] ; then
+    echo $"Usage: ifdown <device name>" >&2
+    exit 1
+fi
+
+usage_and_fail() {
+    cat <<EOF >&2
+$1!
+
+See all profiles with \`nmcli connection\`.
+Reload files from disk with \`nmcli connection reload\`
+Deactivate the desired profile with \`nmcli connection down \"\$NAME\"\`
+EOF
+    exit 1
+}
+
+OLD_IFS="$IFS"
+
+re='^/etc/sysconfig/network-scripts/ifcfg-[^/]+$'
+for f in "/etc/sysconfig/network-scripts/ifcfg-$CONFIG" "/etc/sysconfig/network-scripts/$CONFIG" ; do
+    [[ "$f" =~ $re ]] || continue
+    [ -f "$f" ] || continue
+
+    nmcli connection load "$f" \
+    && nmcli connection down filename "$f" \
+    && exit 0
+
+    usage_and_fail "Failure to deactivate file \"$CONFIG\""
+done
+
+IFS=$'\n '
+APATHS=( $(nmcli -g GENERAL.DBUS-PATH connection show --active "$CONFIG" 2>/dev/null) )
+IFS="$OLD_IFS"
+if [ "${#APATHS[@]}" -eq 1 ] ; then
+    nmcli connection down apath "${APATHS[0]}" \
+    && exit 0
+    usage_and_fail "Failure to deactivate profile \"$CONFIG\" (apath ${APATHS[@]})"
+fi
+
+usage_and_fail "No suitable profile \"$CONFIG\" found"

src/core/settings/plugins/ifcfg-rh/nm-ifup

@@ -1,3 +1,44 @@
-#!/bin/sh
-nmcli connection load "/etc/sysconfig/network-scripts/ifcfg-$1" &&
-exec nmcli connection up filename "/etc/sysconfig/network-scripts/ifcfg-$1"
+#!/bin/bash
+
+CONFIG="$1"
+
+if [ -z "${CONFIG}" ] ; then
+    echo $"Usage: ifup <device name>" >&2
+    exit 1
+fi
+
+usage_and_fail() {
+    cat <<EOF >&2
+$1!
+
+See all profiles with \`nmcli connection\`.
+Reload files from disk with \`nmcli connection reload\`
+Activate the desired profile with \`nmcli connection up \"\$NAME\"\`
+EOF
+    exit 1
+}
+
+OLD_IFS="$IFS"
+
+re='^/etc/sysconfig/network-scripts/ifcfg-[^/]+$'
+for f in "/etc/sysconfig/network-scripts/ifcfg-$CONFIG" "/etc/sysconfig/network-scripts/$CONFIG" ; do
+    [[ "$f" =~ $re ]] || continue
+    [ -f "$f" ] || continue
+
+    nmcli connection load "$f" \
+    && nmcli connection up filename "$f" \
+    && exit 0
+
+    usage_and_fail "Failure to activate file \"$CONFIG\""
+done
+
+IFS=$'\n '
+UUIDS=( $(nmcli -g connection.uuid connection show "$CONFIG" 2>/dev/null) )
+IFS="$OLD_IFS"
+if [ "${#UUIDS[@]}" -eq 1 ] ; then
+    nmcli connection up uuid "${UUIDS[0]}" \
+    && exit 0
+    usage_and_fail "Failure to activate profile \"$CONFIG\" (uuid ${UUIDS[0]})"
+fi
+
+usage_and_fail "No suitable profile \"$CONFIG\" found"