[tbb-commits] [Git][tpo/applications/tor-browser-build][main] 2 commits: Bug 42669: [Part 1] Add uniffi-rs project

Pier Angelo Vendrame pushed to branch main at The Tor Project / Applications / tor-browser-build

Commits: f701f1df by Beatriz Rizental at 2025-02-11T11:55:20+01:00 Bug 42669: [Part 1] Add uniffi-rs project

Apps team forks uniffi and applies a patch to make the Kotlin bindings no-op.

- - - - - 9345a6ea by Beatriz Rizental at 2025-02-11T14:31:15+01:00 Bug 42669: [Part 2] Use custom uniffi-rs in application-services

The apps team custom uniffi-rs implementation removes the dependecy on application-services Rust libraries.

Therefore, this commit also include changes to skip building and including these libs (aka libmegazord) in the final Android application.

- - - - -

15 changed files:

- Makefile - projects/application-services/README.md - + projects/application-services/a-s-noop.diff - − projects/application-services/apply-bug-13028.diff - projects/application-services/bug40485.diff → projects/application-services/bug40485-nimbus-fml-reproducibility.diff - − projects/application-services/bug_13028.patch - projects/application-services/build - + projects/application-services/cargo-no-build.sh - projects/application-services/config - + projects/application-services/glean-noop.diff - projects/application-services/list_toolchain_updates_checks - − projects/application-services/no-ndk-lookup.diff - + projects/uniffi-rs/build - + projects/uniffi-rs/config - rbm.conf

Changes:

===================================== Makefile ===================================== @@ -669,6 +669,9 @@ cargo_vendor-wasm-bindgen: submodule-update cargo_vendor-lox: submodule-update $(rbm) build lox-wasm --step cargo_vendor --target alpha --target torbrowser-linux-x86_64

+cargo_vendor-uniffi-rs: submodule-update + $(rbm) build uniffi-rs --step cargo_vendor --target alpha --target torbrowser-linux-x86_64 + go_vendor-snowflake: submodule-update $(rbm) build snowflake --step go_vendor --target alpha --target torbrowser-linux-x86_64

===================================== projects/application-services/README.md ===================================== @@ -1,6 +1,13 @@ Application Services is a collection of Rust components to enable integration with Mozilla online services, such as the Mozilla account, sync, etc...

+Since all of the application-services features are disabled by the Tor Project browsers, +we don't build or include these Rust libraries in them. Even though these libraries +are written in Rust, they are consumed by Kotlin. Application Services uses uniffi +to auto-generate the Kotlin code that communicates with Rust. We have developed a +custom generator for uniffi (see `projects/uniffi-rs`) to generate no-op bindings, +i.e., bindings that don't call the Rust code and are therefore a dead-end. + We do not fork this project, because we apply a minimal set of patches mainly needed for offline builds.

@@ -13,8 +20,12 @@ References:

## Vendored Rust dependencies

-Application Services is written mainly in Rust and it mnanages external +Application Services is written mainly in Rust and it manages external dependencies through cargo. + +Although most Rust libraries aren't built by this project, the `nimbus-fml` +project -- a command line tool used by other projects -- is still built. + Reproduciblity is guaranteed by the provided `Cargo.lock`.

We run offline builds, so we create the dependency archive in a separate step @@ -35,16 +46,6 @@ We keep the list of files to download in `gradle-dependencies-list.txt`. A procedure to create this file is documented in [tor-browser-build#40855](https://gitlab.torproject.org/tpo/applications/tor-browser-build/-/issues/40...).

-## Other dependencies - -Finally, Application Services depends on two C libraries: -[NSS](https://firefox-source-docs.mozilla.org/security/nss/index.html) and -[SQLCipher](https://www.zetetic.net/sqlcipher/). -We used to have separate tor-browser-build projects for them, but they were -almost an exact copy of the scripts included in this repository. -Keeping them updated wasn't trivial, so we decided to run Mozilla's scripts -instead. - # Caveats

## Git repository information

===================================== projects/application-services/a-s-noop.diff ===================================== @@ -0,0 +1,61 @@ +diff --git a/components/fxa-client/android/src/main/java/mozilla/appservices/fxaclient/Config.kt b/components/fxa-client/android/src/main/java/mozilla/appservices/fxaclient/Config.kt +index 78c16dd0..d2615fa7 100644 +--- a/components/fxa-client/android/src/main/java/mozilla/appservices/fxaclient/Config.kt ++++ b/components/fxa-client/android/src/main/java/mozilla/appservices/fxaclient/Config.kt +@@ -13,4 +13,5 @@ fun FxaServer.contentUrl() = when (this) { + is FxaServer.China -> "https://accounts.firefox.com.cn" + is FxaServer.LocalDev -> "http://127.0.0.1:3030" + is FxaServer.Custom -> this.url ++ is FxaServer.__NOOP -> "" + } +diff --git a/components/nimbus/android/src/main/java/org/mozilla/experiments/nimbus/Nimbus.kt b/components/nimbus/android/src/main/java/org/mozilla/experiments/nimbus/Nimbus.kt +index 8c05be9c..6bf2ec15 100644 +--- a/components/nimbus/android/src/main/java/org/mozilla/experiments/nimbus/Nimbus.kt ++++ b/components/nimbus/android/src/main/java/org/mozilla/experiments/nimbus/Nimbus.kt +@@ -532,6 +532,8 @@ open class Nimbus( + ), + ) + } ++ ++ EnrollmentChangeEventType.__NOOP -> {} + } + } + } +diff --git a/components/places/android/src/main/java/mozilla/appservices/places/PlacesConnection.kt b/components/places/android/src/main/java/mozilla/appservices/places/PlacesConnection.kt +index 282f4e90..db8b00a3 100644 +--- a/components/places/android/src/main/java/mozilla/appservices/places/PlacesConnection.kt ++++ b/components/places/android/src/main/java/mozilla/appservices/places/PlacesConnection.kt +@@ -289,6 +289,7 @@ internal fun VisitType.toInt(): Int { + VisitType.FRAMED_LINK -> 8 + VisitType.RELOAD -> 9 + VisitType.UPDATE_PLACE -> 10 ++ VisitType.__NOOP -> -1 + } + } + +diff --git a/megazords/full/android/build.gradle b/megazords/full/android/build.gradle +index 822ce180..ccdc6c8a 100644 +--- a/megazords/full/android/build.gradle ++++ b/megazords/full/android/build.gradle +@@ -54,6 +54,8 @@ configurations { + } + + cargo { ++ cargoCommand = "${rootDir}/megazords/full/android/cargo-no-build.sh" ++ + // The directory of the Cargo.toml to build. + module = '..' + +diff --git a/publish.gradle b/publish.gradle +index 71f5d55b..027665ff 100644 +--- a/publish.gradle ++++ b/publish.gradle +@@ -194,7 +194,7 @@ ext.configureUniFFIBindgen = { udlFilePath -> + def uniffiGeneratedPath = "generated/source/uniffi/${variant.name}/java" + def t = tasks.register("generate${variant.name.capitalize()}UniFFIBindings", Exec) { + workingDir project.rootDir +- commandLine '/usr/bin/env', 'cargo', 'uniffi-bindgen', 'generate', "${project.projectDir}/${udlFilePath}", '--language', 'kotlin', '--out-dir', "${buildDir}/${uniffiGeneratedPath}" ++ commandLine '/usr/bin/env', "${rootProject.projectDir}/uniffi-rs/uniffi-bindgen", 'generate', "${project.projectDir}/${udlFilePath}", '--language', 'kotlin', '--out-dir', "${buildDir}/${uniffiGeneratedPath}" + outputs.dir "${buildDir}/${uniffiGeneratedPath}" + // Re-generate if the interface definition changes. + inputs.file "${project.projectDir}/${udlFilePath}"

===================================== projects/application-services/apply-bug-13028.diff deleted ===================================== @@ -1,20 +0,0 @@ -diff --git a/libs/build-all.sh b/libs/build-all.sh -index 650c1299..6c4e5404 100755 ---- a/libs/build-all.sh -+++ b/libs/build-all.sh -@@ -128,6 +128,15 @@ echo $'\ - fi - ' | patch "${NSS_SRC_PATH}/nspr/configure" - -+rm -f python -+ln -s /usr/bin/python3 python -+export PATH=$(pwd):$PATH -+patch_13028=$(realpath bug_13028.patch) -+pushd $NSS_SRC_PATH -+# Apply our proxy bypass defense-in-depth here as well to be on the safe side. -+patch -p2 < $patch_13028 -+popd -+ - if [[ "${PLATFORM}" == "ios" ]] - then - ./build-all-ios.sh "${SQLCIPHER_SRC_PATH}" "${NSS_SRC_PATH}"

===================================== projects/application-services/bug40485.diff → projects/application-services/bug40485-nimbus-fml-reproducibility.diff ===================================== @@ -4,16 +4,16 @@ index 97d545672..249406a0c 100644 +++ b/components/support/nimbus-fml/src/intermediate_representation.rs @@ -237,10 +237,10 @@ pub struct FeatureManifest { pub(crate) about: AboutBlock, - + #[serde(default)] - pub(crate) imported_features: HashMap<ModuleId, BTreeSet<String>>, + pub(crate) imported_features: BTreeMap<ModuleId, BTreeSet<String>>, - + #[serde(default)] - pub(crate) all_imports: HashMap<ModuleId, FeatureManifest>, + pub(crate) all_imports: BTreeMap<ModuleId, FeatureManifest>, } - + impl TypeFinder for FeatureManifest { diff --git a/components/support/nimbus-fml/src/parser.rs b/components/support/nimbus-fml/src/parser.rs index 49cace525..cdf692b86 100644 @@ -34,7 +34,7 @@ index 49cace525..cdf692b86 100644 // We associate only the feature ids with the manifest we're loading in this method. - let mut imported_feature_id_map = HashMap::new(); + let mut imported_feature_id_map = BTreeMap::new(); - + for block in &frontend.imports { // 1. Load the imported manifests in to the hash map. @@ -328,7 +328,7 @@ impl Parser {

===================================== projects/application-services/bug_13028.patch deleted ===================================== @@ -1,79 +0,0 @@ -From 2f0888c348561249d3083555db33c5619840dbfa Mon Sep 17 00:00:00 2001 -From: Mike Perry mikeperry-git@torproject.org -Date: Mon, 29 Sep 2014 14:30:19 -0700 -Subject: [PATCH] Bug 13028: Prevent potential proxy bypass cases. - -It looks like these cases should only be invoked in the NSS command line -tools, and not the browser, but I decided to patch them anyway because there -literally is a maze of network function pointers being passed around, and it's -very hard to tell if some random code might not pass in the proper proxied -versions of the networking code here by accident. - -diff --git a/security/nss/lib/certhigh/ocsp.c b/security/nss/lib/certhigh/ocsp.c -index cea8456606bf..86fa971cfbef 100644 ---- a/security/nss/lib/certhigh/ocsp.c -+++ b/security/nss/lib/certhigh/ocsp.c -@@ -2932,6 +2932,14 @@ ocsp_ConnectToHost(const char *host, PRUint16 port) - PRNetAddr addr; - char *netdbbuf = NULL; - -+ // XXX: Do we need a unittest ifdef here? We don't want to break the tests, but -+ // we want to ensure nothing can ever hit this code in production. -+#if 1 -+ printf("Tor Browser BUG: Attempted OSCP direct connect to %s, port %u\n", host, -+ port); -+ goto loser; -+#endif -+ - sock = PR_NewTCPSocket(); - if (sock == NULL) - goto loser; -diff --git a/security/nss/lib/libpkix/pkix_pl_nss/module/pkix_pl_socket.c b/security/nss/lib/libpkix/pkix_pl_nss/module/pkix_pl_socket.c -index e8698376b5be..85791d84a932 100644 ---- a/security/nss/lib/libpkix/pkix_pl_nss/module/pkix_pl_socket.c -+++ b/security/nss/lib/libpkix/pkix_pl_nss/module/pkix_pl_socket.c -@@ -1334,6 +1334,13 @@ pkix_pl_Socket_Create( - plContext), - PKIX_COULDNOTCREATESOCKETOBJECT); - -+ // XXX: Do we need a unittest ifdef here? We don't want to break the tests, but -+ // we want to ensure nothing can ever hit this code in production. -+#if 1 -+ printf("Tor Browser BUG: Attempted pkix direct socket connect\n"); -+ PKIX_ERROR(PKIX_PRNEWTCPSOCKETFAILED); -+#endif -+ - socket->isServer = isServer; - socket->timeout = timeout; - socket->clientSock = NULL; -@@ -1433,6 +1440,13 @@ pkix_pl_Socket_CreateByName( - - localCopyName = PL_strdup(serverName); - -+ // XXX: Do we need a unittest ifdef here? We don't want to break the tests, but -+ // we want to ensure nothing can ever hit this code in production. -+#if 1 -+ printf("Tor Browser BUG: Attempted pkix direct connect to %s\n", serverName); -+ PKIX_ERROR(PKIX_PRNEWTCPSOCKETFAILED); -+#endif -+ - sepPtr = strchr(localCopyName, ':'); - /* First strip off the portnum, if present, from the end of the name */ - if (sepPtr) { -@@ -1582,6 +1596,13 @@ pkix_pl_Socket_CreateByHostAndPort( - PKIX_ENTER(SOCKET, "pkix_pl_Socket_CreateByHostAndPort"); - PKIX_NULLCHECK_THREE(hostname, pStatus, pSocket); - -+ // XXX: Do we need a unittest ifdef here? We don't want to break the tests, but -+ // we want to ensure nothing can ever hit this code in production. -+#if 1 -+ printf("Tor Browser BUG: Attempted pkix direct connect to %s, port %u\n", hostname, -+ portnum); -+ PKIX_ERROR(PKIX_PRNEWTCPSOCKETFAILED); -+#endif - - prstatus = PR_GetHostByName(hostname, buf, sizeof(buf), &hostent); - --- -2.27.0 -

===================================== projects/application-services/build ===================================== @@ -66,13 +66,21 @@ directory = "/var/tmp/build/application-services/vendor" offline=true EOF

-pushd libs -ln -s $rootdir/[% c("input_files_by_name/nss") %] ./ -ln -s $rootdir/bug_13028.patch -patch -p2 < $rootdir/apply-bug-13028.diff -patch -p2 < $rootdir/no-ndk-lookup.diff -./build-all.sh desktop -./build-all.sh android +tar -xf $rootdir/[% c('input_files_by_name/uniffi-rs') %] + +# We add a suffix to the version to make it super specific. +# This is useful for developer builds, which seem to try to fetch +# latest versions of dependencies sometimes. +sed -i '$ s/$/-TORBROWSER/' version.txt + +cp $rootdir/cargo-no-build.sh megazords/full/android/ +chmod +x megazords/full/android/cargo-no-build.sh +patch -p1 < $rootdir/a-s-noop.diff + +pushd components/external/glean +cp $rootdir/cargo-no-build.sh glean-core/android-native/ +cp $builddir/uniffi-rs/uniffi-bindgen glean-core/android-native/ +patch -p1 < $rootdir/glean-noop.diff popd

[% IF c('var/fetch_gradle_dependencies') %] @@ -88,7 +96,7 @@ popd export LANG=C.UTF-8 patch -p1 < $rootdir/local-repository.diff patch -p1 < $rootdir/ohttp-no-git.diff - patch -p1 < $rootdir/bug40485.diff + patch -p1 < $rootdir/bug40485-nimbus-fml-reproducibility.diff patch -p1 < $rootdir/offline-nimbus-fml.diff gradle_flags="--offline --no-daemon" gradle $gradle_flags assembleRelease

===================================== projects/application-services/cargo-no-build.sh ===================================== @@ -0,0 +1,8 @@ +#!/bin/bash + +if [[ "$1" == "build" ]]; then + echo "cargo build is disabled." + exit 0 +else + command cargo "$@" +fi

===================================== projects/application-services/config ===================================== @@ -11,8 +11,8 @@ var: gradle_dependencies_version: 11 gradle_version: 8.8 glean_parser: 14.0.1 - nss_version: '3.101' - nspr_version: '4.35' + # This is the only project for which the rust lib will actually be built + cargo_vendor_subdir: components/support/nimbus-fml

steps: build: @@ -22,9 +22,6 @@ steps: # builds when build time differ a lot, we need to do periodic rebuilds: # https://gitlab.torproject.org/tpo/applications/tor-browser-build/-/merge_req... rebuild_date: '2024-09-12' - arch_deps: - # Needed to build NSS - - gyp input_files: - project: container-image pkg_type: build @@ -40,16 +37,15 @@ steps: - project: ninja name: ninja pkg_type: build + - project: uniffi-rs + name: uniffi-rs + pkg_type: build # Only Application Services currently requires build tools 30.0.3. # So, download them only here, rather than adding them to the shared # toolchain. - URL: 'https://dl.google.com/android/repository/build-tools_r30.0.3-linux.zip' name: build_tools_30 sha256sum: 24593500aa95d2f99fb4f10658aae7e65cb519be6cd33fa164f15f27f3c4a2d6 - # NSS version ans sha256 are in libs/build-all.sh. - - URL: 'https://ftp.mozilla.org/pub/security/nss/releases/NSS_%5B% c("var/nss_version") | replace("\.", "_") %]_RTM/src/nss-[% c("var/nss_version") %]-with-nspr-[% c("var/nspr_version") %].tar.gz' - name: nss - sha256sum: 566faa9283ff3d9a7d6c44272df6e4330e3e06ca4e841a68840d31b27c9161c4 - filename: 'gradle-dependencies-[% c("var/gradle_dependencies_version") %]' name: gradle-dependencies exec: '[% INCLUDE "fetch-gradle-dependencies" %]' @@ -67,15 +63,17 @@ steps: enable: '[% !c("var/fetch_gradle_dependencies") %]' - filename: gen_gradle_deps_file.sh enable: '[% c("var/fetch_gradle_dependencies") %]' - - filename: bug_13028.patch - - filename: apply-bug-13028.diff - # Delete when this patch is included upstream - - filename: bug40485.diff - - filename: no-ndk-lookup.diff + # tor-browser-build#40485: Make sure the Kotlin output of nimbus-fml + # has deterministic order for reproducibility. + # Delete when this patch is included upstream. + - filename: bug40485-nimbus-fml-reproducibility.diff # as-ohttp-client lists both the version for ohttp and a git repo + rev, # but this breaks the vendoring for offline builds. - filename: ohttp-no-git.diff - filename: offline-nimbus-fml.diff + - filename: glean-noop.diff + - filename: a-s-noop.diff + - filename: cargo-no-build.sh

list_toolchain_updates: git_hash: 'v[% c("version") %]'

===================================== projects/application-services/glean-noop.diff ===================================== @@ -0,0 +1,26 @@ +diff --git a/glean-core/android-native/build.gradle b/glean-core/android-native/build.gradle +index 48769651..ade00ec3 100644 +--- a/glean-core/android-native/build.gradle ++++ b/glean-core/android-native/build.gradle +@@ -57,6 +57,8 @@ android { + } + + cargo { ++ cargoCommand = "${rootDir}/glean-core/android-native/cargo-no-build.sh" ++ + // The directory of the Cargo.toml to build. + module = '../bundle-android' + +diff --git a/glean-core/android/build.gradle b/glean-core/android/build.gradle +index 3568e40b..05f28296 100644 +--- a/glean-core/android/build.gradle ++++ b/glean-core/android/build.gradle +@@ -221,7 +221,7 @@ android.libraryVariants.all { variant -> + def udlFilePath = "../src/glean.udl" + def t = tasks.register("generate${variant.name.capitalize()}UniFFIBindings", Exec) { + workingDir project.rootDir +- commandLine 'cargo', 'uniffi-bindgen', 'generate', '--no-format', "${project.projectDir}/${udlFilePath}", '--language', 'kotlin', '--out-dir', "${buildDir}/${uniffiGeneratedPath}" ++ commandLine '${rootDir}/glean-core/android-native/uniffi-bindgen', 'generate', '--no-format', "${project.projectDir}/${udlFilePath}", '--language', 'kotlin', '--out-dir', "${buildDir}/${uniffiGeneratedPath}" + outputs.dir "${buildDir}/${uniffiGeneratedPath}" + // Re-generate if the interface definition changes. + inputs.file "${project.projectDir}/../src/glean.udl"

===================================== projects/application-services/list_toolchain_updates_checks ===================================== @@ -36,13 +36,13 @@ current='[% c("var/gradle_version") %]' check_update_needed gradle "$needed" "$current"

-# nss-nspr +# uniffi read -d '' p << 'EOF' || true -if (m/NSS_ARCHIVE="nss-(.*-with-nspr-.*)\.tar\.gz"/) { +if (m/^\s*uniffi\s*=\s*"([^"]*)"/) { print $1; exit; } EOF -needed=$(cat libs/build-all.sh | perl -ne "$p") -current='[% c("var/nss_version") %]-with-nspr-[% c("var/nspr_version") %]' -check_update_needed nss-nspr "$needed" "$current" +needed=$(cat Cargo.toml | perl -ne "$p") +current='[% pc("uniffi-rs", "version") %]' +check_update_needed uniffi "$needed" "$current"

===================================== projects/application-services/no-ndk-lookup.diff deleted ===================================== @@ -1,18 +0,0 @@ -diff --git a/libs/android_defaults.sh b/libs/android_defaults.sh -index 2cfcc4206..9e3d3de97 100755 ---- a/libs/android_defaults.sh -+++ b/libs/android_defaults.sh -@@ -1,11 +1,7 @@ - #!/usr/bin/env bash - --# Find the NDK. --pushd .. --NDK_VERSION=$(./gradlew -q printNdkVersion | tail -1) --export ANDROID_NDK_HOME="$ANDROID_HOME/ndk/$NDK_VERSION" --export ANDROID_NDK_ROOT="$ANDROID_NDK_HOME" --popd || exit -+# Do not try to find the NDK, as it does not work offline. -+# We already define the needed variables in our environment. - - if [[ -z "${ANDROID_NDK_API_VERSION:-}" ]]; then - export ANDROID_NDK_API_VERSION=21

===================================== projects/uniffi-rs/build ===================================== @@ -0,0 +1,34 @@ +#!/bin/bash +[% c("var/set_default_env") -%] +distdir=/var/tmp/dist +builddir=/var/tmp/build/[% project %] +mkdir -p $distdir/[% project %] +tar -C /var/tmp/dist -xf $rootdir/[% c('input_files_by_name/rust') %] +export PATH="/var/tmp/dist/rust/bin:$PATH" +[% IF c("var/linux") -%] + export LD_LIBRARY_PATH="/var/tmp/dist/rust/lib:$LD_LIBRARY_PATH" +[% END -%] +mkdir -p /var/tmp/build +tar -C /var/tmp/build -xf [% project %]-[% c('version') %].tar.[% c('compress_tar') %] + +# Now prepare the offline build +# Move the directory for hardcoding the path in .cargo/config +mv /var/tmp/build/[% project %]-[% c('version') %] $builddir +tar -C $builddir -xf $rootdir/[% c('input_files_by_name/cargo_vendor') %] +cd $builddir +cat >> .cargo/config << 'EOF' +[source.crates-io] +replace-with = "vendored-sources" + +[source.vendored-sources] +directory = "/var/tmp/build/uniffi-rs/vendor" +EOF + +cargo build --release --frozen --target x86_64-unknown-linux-gnu +mv target/x86_64-unknown-linux-gnu/release/uniffi-bindgen $distdir/[% project %] + +cd $distdir +[% c('tar', { + tar_src => [ project ], + tar_args => '-caf ' _ dest_dir _ '/' _ c('filename'), + }) %]

===================================== projects/uniffi-rs/config ===================================== @@ -0,0 +1,20 @@ +# vim: filetype=yaml sw=2 +version: 0.27.1 +git_hash: bfb52effb0292f16d4c030d622887781639cbd1f +git_url: https://gitlab.torproject.org/tpo/applications/uniffi-rs.git +container: + use_container: 1 + +steps: + build: + filename: '[% project %]-[% c("version") %]-[% c("var/build_id") %].tar.[% c("compress_tar") %]' + input_files: + - project: container-image + pkg_type: build + - project: rust + name: rust + - name: cargo_vendor + project: uniffi-rs + pkg_type: cargo_vendor + norec: + sha256sum: 12a61a3dbe65a3946ed58fff3d849d11c9ade5818e2ef5771d2a2a531e25f553

===================================== rbm.conf ===================================== @@ -30,7 +30,7 @@ steps: export PATH="/var/tmp/dist/rust/bin:$PATH" tar -xf [% project %]-[% c('version') %].tar.[% c('compress_tar') %] cd [% project %]-[% c('version') %] - cargo vendor --locked vendor + cargo vendor --locked vendor --manifest-path [% IF c('var/cargo_vendor_subdir') %][% c('var/cargo_vendor_subdir') %]/[% END %]Cargo.toml [% c('tar', { tar_src => [ 'vendor' ], tar_args => '-caf ' _ dest_dir _ '/' _ c('filename'),

View it on GitLab: https://gitlab.torproject.org/tpo/applications/tor-browser-build/-/compare/4...