[PATCH v2 6/7] host/rootfs: run transient VMs with persistence

[Alyssa Ross <hi@alyssa.is>]

This allows run-appimage and run-flatpak to be given the name of a
previously saved persistent directory.  Further writes by the
application to that directory will also be persisted.

Signed-off-by: Alyssa Ross <hi@alyssa.is>
---
v2: new this round

 host/rootfs/image/usr/bin/run-appimage | 16 +++++++++++++---
 host/rootfs/image/usr/bin/run-flatpak  | 15 +++++++++++++--
 2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/host/rootfs/image/usr/bin/run-appimage b/host/rootfs/image/usr/bin/run-appimage
index de851c52..24621065 100755
--- a/host/rootfs/image/usr/bin/run-appimage
+++ b/host/rootfs/image/usr/bin/run-appimage
@@ -26,13 +26,23 @@ if {
 }
 
 backtick diskdir {
-  s6-setuidgid fs
-
-  backtick -E mountpoint {
+  backtick mountpoint {
     importas -Siu 1
     findmnt -no TARGET -T $1
   }
 
+  if -tn {
+    redirfd -w 2 /dev/null
+    multisubstitute {
+      importas -Siu mountpoint
+      importas -Siu 2
+    }
+    printf "%s/Spectrum/data/spectrum/storage/persist.%s\n" $mountpoint $2
+  }
+
+  s6-setuidgid fs
+
+  importas -Siu mountpoint
   if { mkdir -p -- ${mountpoint}/Spectrum/data/spectrum/storage }
   mktemp -d -- ${mountpoint}/Spectrum/data/spectrum/storage/tmp.XXXXXX
 }
diff --git a/host/rootfs/image/usr/bin/run-flatpak b/host/rootfs/image/usr/bin/run-flatpak
index b47204c9..4123d329 100755
--- a/host/rootfs/image/usr/bin/run-flatpak
+++ b/host/rootfs/image/usr/bin/run-flatpak
@@ -26,6 +26,15 @@ if {
 }
 
 backtick diskdir {
+  if -tn {
+    redirfd -w 2 /dev/null
+    multisubstitute {
+      importas -Siu 1
+      importas -Siu 4
+    }
+    printf "%s/Spectrum/data/spectrum/storage/persist.%s\n" $1 $4
+  }
+
   s6-setuidgid fs
 
   importas -Siu 1
@@ -41,7 +50,9 @@ if {
   multisubstitute {
     importas -Siu id
     importas -Siu diskdir
-    elgetpositionals
+    importas -Siu 1
+    importas -Siu 2
+    importas -Siu 3
   }
 
   nsenter --preserve-credentials -S0
@@ -50,7 +61,7 @@ if {
 
   cd /run/fs/${id}/config
   if { redirfd -w 1 type echo flatpak }
-  if { mount-flatpak $@ }
+  if { mount-flatpak $1 $2 $3 }
 
   mount --bind -- $diskdir /run/fs/${id}/disk
 }
-- 
2.51.0