chore: sync dev and trim redundant event tests

scripts/set_dns.sh

@@ -30,29 +30,51 @@ function is_valid_ip() {
     is_valid_ipv4 "$1" || is_valid_ipv6 "$1"
 }
 
+# Prints one value of a SystemConfiguration dictionary, or nothing when the key is absent.
+function sc_value() {
+    printf 'show %s\nquit\n' "$1" | scutil | sed -n "s/^ *$2 : //p"
+}
+
+# Prints the service's DNS servers, or "empty" when none is set; fails on any other answer.
+function dns_of() {
+    local dns line ip='^[0-9A-Fa-f]*[.:][0-9A-Fa-f.:]*(%[[:alnum:]_.-]+)?$'
+    dns=$(networksetup -getdnsservers "$1") || return 1
+    if [ "$dns" = "There aren't any DNS Servers set on $1." ]; then
+        echo "empty"
+        return
+    fi
+    [ -n "$dns" ] || return 1
+    while read -r line; do
+        [[ $line =~ $ip ]] || return 1
+    done <<<"$dns"
+    echo "$dns"
+}
+
 [ $# -lt 1 ] && echo "Usage: $0 <IP address>" && exit 1
 ! is_valid_ip "$1" && echo "$1 is not a valid IP address." && exit 1
 
-nic=$(route -n get default | grep "interface" | awk '{print $2}')
-hardware_port=$(networksetup -listnetworkserviceorder | awk -v dev="$nic" '
-    /^\([0-9]+\) /{port=$0; sub(/^\([0-9]+\) /, "", port)} 
-    /\(Hardware Port:/{interface=$NF;sub(/\)/, "", interface); if (interface == dev) {print port; exit}}
-')
+# Backups are keyed by service ID, which survives renaming the service and renumbering its interface.
+service_id=$(sc_value State:/Network/Global/IPv4 PrimaryService)
+hardware_port=$(sc_value "Setup:/Network/Service/$service_id" UserDefinedName)
+[ -z "$hardware_port" ] && echo "No primary network service." && exit 1
 
-original_dns=$(networksetup -getdnsservers "$hardware_port")
+original_dns=$(dns_of "$hardware_port") || { echo "Cannot read DNS servers of $hardware_port." >&2; exit 1; }
 
-is_valid_dns=false
-for ip in $original_dns; do
-    ip=$(echo "$ip" | tr -d '[:space:]')
-    if [ -n "$ip" ] && (is_valid_ipv4 "$ip" || is_valid_ipv6 "$ip"); then
-        is_valid_dns=true
-        break
+backup=".original_dns/$service_id"
+mkdir -p .original_dns || exit 1
+# Older releases kept a single backup for whichever service was primary.
+if [ -f .original_dns.txt ]; then
+    if [ -f "$backup" ]; then
+        rm -f .original_dns.txt || exit 1
+    else
+        mv .original_dns.txt "$backup" || exit 1
     fi
-done
-
-if [ "$is_valid_dns" = false ]; then
-    echo "empty" >.original_dns.txt
-else
-    echo "$original_dns" >.original_dns.txt
 fi
-networksetup -setdnsservers "$hardware_port" "$1"
+# The placeholder is ours, not the user's: keep the backup taken before it was applied.
+if [ "$original_dns" != "$1" ]; then
+    echo "$original_dns" >"$backup" || exit 1
+    networksetup -setdnsservers "$hardware_port" "$1"
+    [ "$(dns_of "$hardware_port")" = "$1" ] || { echo "Failed to set DNS for $hardware_port." >&2; exit 1; }
+elif [ ! -f "$backup" ]; then
+    echo "empty" >"$backup" || exit 1
+fi

scripts/unset_dns.sh

@@ -1,13 +1,62 @@
 #!/bin/bash
-nic=$(route -n get default | grep "interface" | awk '{print $2}')
+[ $# -lt 1 ] && echo "Usage: $0 <placeholder IP address>" && exit 1
 
-hardware_port=$(networksetup -listnetworkserviceorder | awk -v dev="$nic" '
-    /^\([0-9]+\) /{port=$0; sub(/^\([0-9]+\) /, "", port)} 
-    /\(Hardware Port:/{interface=$NF;sub(/\)/, "", interface); if (interface == dev) {print port; exit}}
-')
+# Prints one value of a SystemConfiguration dictionary, or nothing when the key is absent.
+function sc_value() {
+    printf 'show %s\nquit\n' "$1" | scutil | sed -n "s/^ *$2 : //p"
+}
 
+# Prints the service's DNS servers, or "empty" when none is set; fails on any other answer.
+function dns_of() {
+    local dns line ip='^[0-9A-Fa-f]*[.:][0-9A-Fa-f.:]*(%[[:alnum:]_.-]+)?$'
+    dns=$(networksetup -getdnsservers "$1") || return 1
+    if [ "$dns" = "There aren't any DNS Servers set on $1." ]; then
+        echo "empty"
+        return
+    fi
+    [ -n "$dns" ] || return 1
+    while read -r line; do
+        [[ $line =~ $ip ]] || return 1
+    done <<<"$dns"
+    echo "$dns"
+}
+
+result=0
+# Older releases kept a single backup for whichever service was primary.
 if [ -f .original_dns.txt ]; then
-    original_dns=$(cat .original_dns.txt)
-    networksetup -setdnsservers "$hardware_port" $original_dns
-    rm -rf .original_dns.txt
+    service_id=$(sc_value State:/Network/Global/IPv4 PrimaryService)
+    if [ -z "$service_id" ] || ! mkdir -p .original_dns; then
+        result=1
+    elif [ -f ".original_dns/$service_id" ]; then
+        rm -f .original_dns.txt || result=1
+    elif ! mv .original_dns.txt ".original_dns/$service_id"; then
+        result=1
+    fi
 fi
+
+for backup in .original_dns/*; do
+    [ -f "$backup" ] || continue
+    hardware_port=$(sc_value "Setup:/Network/Service/${backup##*/}" UserDefinedName)
+    # Kept for a service that is gone: there is nothing to write it back to.
+    [ -n "$hardware_port" ] || continue
+    if ! current_dns=$(dns_of "$hardware_port"); then
+        echo "Cannot read DNS servers of $hardware_port." >&2
+        result=1
+        continue
+    fi
+    # A service no longer on the placeholder was changed by someone else, and that change stands.
+    if [ "$current_dns" = "$1" ]; then
+        original_dns=$(cat "$backup") || { result=1; continue; }
+        # Older releases could back up the placeholder itself.
+        [ "$original_dns" = "$1" ] && original_dns=empty
+        networksetup -setdnsservers "$hardware_port" $original_dns
+        if [ "$(dns_of "$hardware_port")" != "$original_dns" ]; then
+            echo "Failed to restore DNS for $hardware_port." >&2
+            result=1
+            continue
+        fi
+    fi
+    rm -f "$backup" || result=1
+done
+rmdir .original_dns 2>/dev/null
+exit $result