Move cargo vendor output to prevent conflicts and acquire file lock beforehand

This change modifies where we save the cargo configuration from cargo vendor to avoid interfering with manual
cargo operations in subdirectories. In addition, we now acquire a file lock before running cargo vendor to prevent
parallel builds from running cargo vendor at the same time.

Key Changes:

* Generate cargo vendor config to `.cargo/twoliter_cargo_config.toml` instead of `.cargo/config.toml`
* Update build.Dockerfile to mount `.cargo/twoliter_cargo_config.toml` to `.cargo/config.toml` internally
* Update all docker run commands in Makefile.toml to do the same as above
* Acquire a file lock on `.cargo/vendor.lock` before running cargo vendor to prevent parallel runs of cargo vendor

These changes resolve two issues:

* Prevents `cargo vendor` runs from occuring at the same time causing mutations to the vendored sources during parallel builds.
* Prevents manual cargo commands in sub-workspaces from entering a dependency resolution loop because of the vendored sources

Author: jmt-lab

twoliter/embedded/Makefile.toml

@@ -362,13 +362,31 @@ for ws in sources variants .; do
   [ -s "${BUILDSYS_ROOT_DIR}/${ws}/Cargo.lock" ] || continue
   CARGO_MANIFESTS+=(--sync "${BUILDSYS_ROOT_DIR}/${ws}/Cargo.toml")
 done
-cargo vendor --locked --no-delete  --versioned-dirs --respect-source-config  ${CARGO_MANIFESTS[@]} .cargo/vendor > .cargo/config.toml 2> .cargo/vendor.log || {
-   echo "vendoring of cargo dependencies failed"
-   cat .cargo/vendor.log
+exec 9<>.cargo/vendor.lock
+if ! flock -w 90 9; then
+    echo "failed to obtain lock" >&2
+    exit 1
+fi
+
+set +e
+cargo vendor \
+    --locked \
+    --no-delete \
+    --versioned-dirs \
+    --respect-source-config \
+    ${CARGO_MANIFESTS[@]} \
+    .cargo/vendor \
+    > .cargo/twoliter_cargo_config.toml \
+    2> .cargo/vendor.log
+
+if [ "${?}" -ne 0 ]; then
+   echo "vendoring of cargo dependencies failed" >&2
+   cat .cargo/vendor.log >&2
    exit 1
-}
-rm .cargo/vendor.log
+fi
 
+set -e
+rm .cargo/vendor.log
 chmod -R o+r ${CARGO_HOME}
 '''
 ]
@@ -459,7 +477,8 @@ done
 if ! docker run --rm \
    -u $(id -u):$(id -g) \
    -e CARGO_HOME="/tmp/.cargo" \
-   -v "${CARGO_HOME}":/tmp/.cargo \
+   -v "${CARGO_HOME}/twoliter_cargo_config.toml":/tmp/.cargo/config.toml \
+   -v "${CARGO_HOME}/vendor":/tmp/.cargo/vendor \
    -v "${BUILDSYS_ROOT_DIR}/sources":/tmp/sources \
    "${TLPRIVATE_SDK_IMAGE}" \
    cargo fmt \
@@ -495,7 +514,8 @@ export VARIANT="${BUILDSYS_VARIANT}"
 if ! docker run --rm \
    -u $(id -u):$(id -g) \
    -e CARGO_HOME="/tmp/.cargo" \
-   -v "${CARGO_HOME}":/tmp/.cargo \
+   -v "${CARGO_HOME}/twoliter_cargo_config.toml":/tmp/.cargo/config.toml \
+   -v "${CARGO_HOME}/vendor":/tmp/.cargo/vendor \
    -v "${BUILDSYS_ROOT_DIR}/sources":/tmp/sources \
    -e VARIANT \
    "${TLPRIVATE_SDK_IMAGE}" \
@@ -978,7 +998,8 @@ docker run --rm \
   --user "$(id -u):$(id -g)" \
   --security-opt="label=disable" \
   -e CARGO_HOME="/tmp/.cargo" \
-  -v "${CARGO_HOME}":/tmp/.cargo \
+  -v "${CARGO_HOME}/twoliter_cargo_config.toml":/tmp/.cargo/config.toml \
+  -v "${CARGO_HOME}/vendor":/tmp/.cargo/vendor \
   -v "${BUILDSYS_ROOT_DIR}/sources":/tmp/sources \
   "${TLPRIVATE_SDK_IMAGE}" \
   bash -c "${run_cargo_deny}"

twoliter/embedded/build.Dockerfile

@@ -112,7 +112,7 @@ USER builder
     # We only mount the config.toml and the vendor directory instead of the whole .cargo directory
     # because the .git and .registry directories are specific to the version of cargo and can cause
     # incapatibility between the host cargo and the cargo in the sdk
-RUN --mount=source=.cargo/config.toml,target=/home/builder/rpmbuild/.cargo/config.toml \
+RUN --mount=source=.cargo/twoliter_cargo_config.toml,target=/home/builder/rpmbuild/.cargo/config.toml \
     --mount=source=.cargo/vendor,target=/home/builder/rpmbuild/.cargo/vendor \
     --mount=type=cache,target=/home/builder/.cache,from=cache,source=/cache \
     --mount=source=sources,target=/home/builder/rpmbuild/BUILD/sources \