From: Ralph Ronnquist <ralph.ronnquist@gmail.com>
Date: Mon, 21 Mar 2022 03:28:35 +0000 (+1100)
Subject: improved subhost mounting
X-Git-Tag: deb_0.1~26
X-Git-Url: https://git.rrq.au/?a=commitdiff_plain;h=fef769fc5a66825081639490a6567f9df8f43193;p=rrq%2Foverlay-boot.git

improved subhost mounting
---

diff --git a/functions b/functions
index 1d52d74..38e8725 100644
--- a/functions
+++ b/functions
@@ -60,21 +60,47 @@ REAPER=$(dirname $(realpath $0))/reaper/reaper
 # Set up an overlay fmr $name on $live, with a new tmpfs on its /run,
 # and "install" a "reaper" as the upcoming pid 1
 setup_overlay() {
-    set -x
-    mkdir -p $4/run
-    mount -t tmpfs -osize=100M tmpfs $4/run
-    mkdir -p $4/run/lock
-    grep -q "$1 $2" /proc/mounts || \
-	mount -t overlay -olowerdir=$3,upperdir=$4,workdir=$5 $1 $2 || \
-	die "Cannot set up the overlay mount $2"
-    mount --bind $4/run $2/run
-    cp $REAPER $LIVE/.reaper
-}
+    local ROOT="$4"
+    local LIVE="$2"
 
+    if grep -q "$1 $2" /proc/mounts ; then
+	die "$1 is already mounted"
+    fi
 
-# Check if $SRV is "live" ; will 
-is_live() {
-    pgrep -f ".reaper $SRV" > /dev/null
+    # setup $ROOT/run
+    mkdir -p "$ROOT/run"
+    mount -t tmpfs -osize=100M tmpfs "$ROOT/run"
+    mkdir -p "$ROOT/run/lock"
+    # setup $ROOT/dev
+    mkdir -p "$ROOT/dev"
+    mount -t tmpfs -osize=100M tmpfs "$ROOT/dev"
+    mknod -m 622 "$ROOT/dev/console" c 5 1
+    mknod -m 666 "$ROOT/dev/null" c 1 3
+    mknod -m 666 "$ROOT/dev/zero" c 1 5
+    mknod -m 666 "$ROOT/dev/ptmx" c 5 2
+    mknod -m 666 "$ROOT/dev/tty" c 5 0
+    mknod -m 444 "$ROOT/dev/random" c 1 8
+    mknod -m 444 "$ROOT/dev/urandom" c 1 9
+    chown root:tty "$ROOT/dev/console"
+    chown root:tty "$ROOT/dev/ptmx"
+    chown root:tty "$ROOT/dev/tty"
+    ln -sTf /proc/self/fd "$ROOT/dev/fd"
+    ln -sTf /proc/self/fd/0 "$ROOT/dev/stdin"
+    ln -sTf /proc/self/fd/1 "$ROOT/dev/stdout"
+    ln -sTf /proc/self/fd/2 "$ROOT/dev/stderr"
+    ln -sTf /proc/kcore "$ROOT/dev/core"
+    mkdir "$ROOT/dev/shm"
+    mkdir "$ROOT/dev/pts"
+    chmod 1777 "$ROOT/dev/shm"
+
+    if mount -t overlay -olowerdir=$3,upperdir=$4,workdir=$5 $1 $2 ; then
+	: # all good
+    else
+	umount -R "$ROOT/dev"
+	umount "$ROOT/run"
+	die "Cannot set up the overlay mount $2"
+    fi
+    cp $REAPER $LIVE/.reaper
 }
 
 start_services() {
@@ -82,3 +108,17 @@ start_services() {
 	service $S start
     done
 }
+
+# find the upperdir option for an overlay mount line
+getupper() {
+    sed 's/.*upperdir=\([^,]*\).*/\1/'
+}
+
+# Check if $1 is "live" and echo the
+# unshare and reaper process pids
+is_live() {
+    local NAME=$1
+    local USPID="$(pgrep -f "unshare.* $NAME ")"
+    [ -z "$USPID" ] && return 1
+    echo $USPID $(pgrep -f ".reaper $NAME")
+}