fix(linux): move captures out of protected CUPS cache

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@fieldlens/print",
-  "version": "0.1.14",
+  "version": "0.1.15",
   "private": true,
   "type": "module",
   "scripts": {

src-tauri/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "fieldlens-print"
-version = "0.1.14"
+version = "0.1.15"
 description = "FieldLens print-stream barcode capture companion"
 authors = ["Arrowstack"]
 edition = "2021"

src-tauri/src/capture.rs

@@ -25,7 +25,7 @@ use crate::{
 };
 
 #[cfg(target_os = "linux")]
-const SYSTEM_CUPS_SPOOL_DIR: &str = "/var/cache/cups/fieldlens-print";
+const SYSTEM_CUPS_SPOOL_DIR: &str = "/var/lib/fieldlens-print/capture";
 #[cfg(target_os = "linux")]
 const TEST_CAPTURE_SINK_ADDR: &str = "127.0.0.1:9101";
 

src-tauri/src/printers.rs

@@ -20,14 +20,14 @@ const TEST_CAPTURE_DEVICE_URI: &str = "socket://127.0.0.1:9101";
 const WINDOWS_PORT_NAME: &str = "FieldLensPrint-9100";
 
 #[cfg(target_os = "linux")]
-const FIELDLENS_CUPS_SPOOL_DIR: &str = "/var/cache/cups/fieldlens-print";
+const FIELDLENS_CUPS_SPOOL_DIR: &str = "/var/lib/fieldlens-print/capture";
 #[cfg(target_os = "linux")]
 const FIELDLENS_CUPS_FILTER: &str = r#"#!/usr/bin/python3
 import os
 import re
 import sys
 
-CACHE = os.path.join(os.environ.get("CUPS_CACHEDIR", "/var/cache/cups"), "fieldlens-print")
+CACHE = "/var/lib/fieldlens-print/capture"\nOWNER_UID = __FIELDLENS_OWNER_UID__\nOWNER_GID = __FIELDLENS_OWNER_GID__
 
 def safe(value):
     value = re.sub(r"[^A-Za-z0-9._-]+", "-", value or "job").strip("-")
@@ -84,7 +84,13 @@ try:
         capture.flush()
         capture.close()
         capture = None
-        os.chmod(part_path, 0o644)
+        os.chmod(part_path, 0o600)
+        try:
+            os.chown(part_path, OWNER_UID, OWNER_GID)
+        except PermissionError:
+            # On this Linux lane CUPS runs filters as root. Keep printing alive
+            # if a future CUPS policy drops privileges; repair can surface it.
+            pass
         os.replace(part_path, final_path)
         captured_ok = True
         print(f"INFO: FieldLens captured {name}", file=sys.stderr)
@@ -111,9 +117,12 @@ target_printer = sys.argv[1]
 target_port = sys.argv[2]
 temp_filter = sys.argv[3]
 filter_path = sys.argv[4]
+owner_uid = int(sys.argv[5])
+owner_gid = int(sys.argv[6])
 
 source_ppd = os.path.join("/etc/cups/ppd", f"{target_printer}.ppd")
-spool_dir = "/var/cache/cups/fieldlens-print"
+spool_dir = "/var/lib/fieldlens-print/capture"
+old_spool_dir = "/var/cache/cups/fieldlens-print"
 
 with open(source_ppd, "r", encoding="utf-8", errors="replace") as source:
     original = source.read()
@@ -142,7 +151,31 @@ try:
         target.write(cleaned)
 
     subprocess.run(["install", "-m", "0755", temp_filter, filter_path], check=True)
-    subprocess.run(["install", "-d", "-m", "0777", spool_dir], check=True)
+
+    os.makedirs(spool_dir, exist_ok=True)
+    os.chown(spool_dir, owner_uid, owner_gid)
+    os.chmod(spool_dir, 0o700)
+
+    # Bring forward captures stranded by 0.1.13/0.1.14 in CUPS' protected
+    # cache. Ignore directories and partial writes.
+    if os.path.isdir(old_spool_dir):
+        for name in os.listdir(old_spool_dir):
+            source = os.path.join(old_spool_dir, name)
+            if not os.path.isfile(source) or name.endswith(".part"):
+                continue
+            target = os.path.join(spool_dir, name)
+            if os.path.exists(target):
+                root, ext = os.path.splitext(name)
+                target = os.path.join(spool_dir, f"{root}-migrated{ext}")
+            try:
+                os.replace(source, target)
+            except OSError:
+                continue
+            try:
+                os.chown(target, owner_uid, owner_gid)
+                os.chmod(target, 0o600)
+            except OSError:
+                pass
 
     subprocess.run([
         "lpadmin", "-p", "FieldLens-Print", "-E",
@@ -685,7 +718,24 @@ fn install_linux_virtual_printer(target_printer: &str) -> Result<()> {
         uuid::Uuid::new_v4()
     ));
 
-    fs::write(&temp_filter, FIELDLENS_CUPS_FILTER)
+    let uid = Command::new("id")
+        .arg("-u")
+        .output()
+        .context("read current Linux user id")?;
+    let gid = Command::new("id")
+        .arg("-g")
+        .output()
+        .context("read current Linux group id")?;
+    if !uid.status.success() || !gid.status.success() {
+        return Err(anyhow!("could not determine the current Linux user for capture ownership"));
+    }
+    let uid = String::from_utf8_lossy(&uid.stdout).trim().to_string();
+    let gid = String::from_utf8_lossy(&gid.stdout).trim().to_string();
+
+    let filter_script = FIELDLENS_CUPS_FILTER
+        .replace("__FIELDLENS_OWNER_UID__", &uid)
+        .replace("__FIELDLENS_OWNER_GID__", &gid);
+    fs::write(&temp_filter, filter_script)
         .context("write FieldLens CUPS capture filter")?;
     fs::write(&temp_helper, FIELDLENS_CUPS_REPAIR_HELPER)
         .context("write FieldLens CUPS repair helper")?;
@@ -697,6 +747,8 @@ fn install_linux_virtual_printer(target_printer: &str) -> Result<()> {
         .arg(&target.port)
         .arg(&temp_filter)
         .arg(&filter_path)
+        .arg(&uid)
+        .arg(&gid)
         .status()
         .context("run elevated FieldLens CUPS repair")?;
 

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "FieldLens Print",
-  "version": "0.1.14",
+  "version": "0.1.15",
   "identifier": "dev.arrowstack.fieldlens.print",
   "build": {
     "beforeDevCommand": "npm run dev",

src/main.ts

@@ -85,7 +85,7 @@ let config: AppConfig
 let jobs: Job[] = []
 let status: Status
 let loginTimer: number | undefined
-let currentVersion = '0.1.14'
+let currentVersion = '0.1.15'
 let bundleType: BundleType | null = null
 let availableUpdate: Update | null = null
 let availableManualUpdate: ManualUpdate | null = null