sanebox: forward argv0

modules/programs/make-sandboxed.nix

@@ -4,7 +4,8 @@
   buildPackages,
   file,
   gnugrep,
-  makeBinaryWrapper,
+  gnused,
+  makeWrapper,
   runCommandLocal,
   runtimeShell,
   sanebox,
@@ -60,7 +61,8 @@ let
       # the ordering here is specific: inject our deps BEFORE the unwrapped program's
       # so that the unwrapped's take precendence and we limit interference (e.g. makeWrapper impl)
       fakeSaneSandboxed
-      makeBinaryWrapper
+      gnugrep
+      makeWrapper
     ] ++ (unwrapped.nativeBuildInputs or []);
     disallowedReferences = (unwrapped.disallowedReferences or []) ++ [
       # the fake sandbox gates itself behind SANEBOX_DISABLE, so if it did end up deployed
@@ -73,15 +75,14 @@ let
         # my programs refer to sanebox by name, not path, which triggers an over-eager assertion in nixpkgs (so, mask that)
         :
       }
-      makeDocumentedCWrapper() {
+      # makeDocumentedCWrapper() {
-        # this is identical to nixpkgs' implementation, only replace execv with execvp, the latter which looks for the executable on PATH.
+      #   # this is identical to nixpkgs' implementation, only replace execv with execvp, the latter which looks for the executable on PATH.
-        local src docs
+      #   local src=$(makeCWrapper "$@")
-        src=$(makeCWrapper "$@")
+      #   src="''${src/return execv(/return execvp(}"
-        src="''${src/return execv(/return execvp(}"
+      #   local docs=$(docstring "$@")
-        docs=$(docstring "$@")
+      #   printf '%s\n\n' "$src"
-        printf '%s\n\n' "$src"
+      #   printf '%s\n' "$docs"
-        printf '%s\n' "$docs"
+      # }
-      }
 
       sandboxWrap() {
         local _dir="$1"
@@ -90,8 +91,7 @@ let
         # N.B.: unlike stock `wrapProgram`, we place the unwrapped binary in a subdirectory and *preserve its name*.
         # the upside of this is that for applications which read "$0" to decide what to do (e.g. busybox, git)
         # they work as expected without any special hacks.
-        # if desired, makeWrapper-style naming could be achieved by leveraging `exec -a <original_name>`
+        # though even so, the sandboxer still tries to preserve the $0 which it was invoked under
-        # or `make-wrapper --inherit-argv0`
         mkdir -p "$_dir/.sandboxed"
         if [[ "$(readlink $_dir/$_name)" =~ ^\.\./ ]]; then
           # relative links which ascend a directory (into a non-bin/ directory)
@@ -101,7 +101,13 @@ let
         else
           mv "$_dir/$_name" "$_dir/.sandboxed/"
         fi
-        makeBinaryWrapper ${sanebox'} "$_dir/$_name" --suffix PATH : /run/current-system/sw/libexec/sanebox ${lib.escapeShellArgs (lib.flatten (builtins.map (f: [ "--add-flags" f ]) extraSandboxArgs))} --add-flags "$_dir/.sandboxed/$_name"
+        makeShellWrapper ${sanebox'} "$_dir/$_name" --suffix PATH : /run/current-system/sw/libexec/sanebox \
+          ${lib.escapeShellArgs (lib.flatten (builtins.map (f: [ "--add-flags" f ]) extraSandboxArgs))} \
+          --add-flags "$_dir/.sandboxed/$_name"
+        # `exec`ing a script with an interpreter will smash $0. instead, source it to preserve $0:
+        # - <https://github.com/NixOS/nixpkgs/issues/150841#issuecomment-995589961>
+        substituteInPlace "$_dir/$_name" \
+          --replace-fail 'exec ' 'source '
       }
 
       crawlAndWrap() {

pkgs/additional/sanebox/sanebox

@@ -94,6 +94,14 @@ netGateway=default
 dns=()
 # VAR -> VALUE map of environment variables to add to the sandboxed program's environment
 declare -A portalEnv
+argv0=
+case "${0:-8}" in
+  ("sanebox"|"/sanebox")
+    ;;
+  (*)
+    argv0="$0"
+    ;;
+esac
 
 # arguments to forward onto a specific backend (if that backend is active)
 bwrapArgs=()
@@ -501,6 +509,7 @@ parseArgs() {
         # this lets the user do things like `mpv --sanebox-replace-cli sh` to enter a shell
         # with the sandbox that `mpv` would see.
         parseArgsExtra=()
+        argv0=
         ;;
       (--sanebox-disable)
         isDisable=1
@@ -754,7 +763,8 @@ bwrapGetCli() {
   done
 
   cliArgs=(
-    "$_bwrap" \
+    "$_bwrap"
+      --argv0 "$argv0"
       "${bwrapUnshareCgroup[@]}"
       "${bwrapUnshareIpc[@]}"
       "${bwrapUnshareNet[@]}"
@@ -921,7 +931,7 @@ capshonlyGetCli() {
   locate _capsh "capsh" "$CAPSH_FALLBACK"
   locate _env "env" "$ENV_FALLBACK"
 
-  local envArgs=()
+  local envArgs=(-a "$argv0")
   for envName in "${!portalEnv[@]}"; do
     envArgs+=("$envName=${portalEnv[$envName]}")
   done
@@ -984,7 +994,7 @@ pastaonlyIngestCapability() {
 pastaonlyGetCli() {
   cliArgs=(
     "/bin/sh" "-c"
-    "$pastaNetSetup exec"' "$0" "$@"'
+    "$pastaNetSetup exec"' "$argv0" "$@"'
     "${cliArgs[@]}"
   )
   locate _pasta "pasta" "$PASTA_FALLBACK"
@@ -1032,7 +1042,7 @@ noneIngestCapability() {
   :
 }
 noneGetCli() {
-  :
+  cliArgs=(-a "$argv0" "${cliArgs[@]}")
 }
 
 
@@ -1138,6 +1148,9 @@ parseArgsAndEnvironment() {
 
   parseArgs "$@"
   cliArgs+=("${parseArgsExtra[@]}")
+  if [ -z "$argv0" ]; then
+    argv0=${cliArgs[0]}
+  fi
 
   if [ -n "$SANEBOX_APPEND" ]; then
     parseArgs $SANEBOX_APPEND
@@ -1175,6 +1188,9 @@ ingestForBackend() {
 ## TOPLEVEL EXECUTION
 #  no code evaluated before this point should be dependent on user args / environment.
 
+# TODO: use `set -e`, only i'm using `return 1` in places for control flow.
+set +e
+
 parseArgsAndEnvironment "$@"
 
 # variables meant to be inherited