linux/scripts/rust_is_available.sh
Miguel Ojeda e90db5521d kbuild: rust_is_available: check that environment variables are set
Sometimes [1] users may attempt to setup the Rust support by
checking what Kbuild does and they end up finding out about
`scripts/rust_is_available.sh`. Inevitably, they run the script
directly, but unless they setup the required variables,
the result of the script is not meaningful.

We could add some defaults to the variables, but that could be
confusing for those that may override the defaults (compared
to their kernel builds), and `$CC` would not be a simple default
in any case.

Therefore, instead, explicitly check whether the expected variables
are set (`$RUSTC`, `$BINDGEN` and `$CC`). If not, print an explanation
about the fact that the script is meant to be called from Kbuild,
since that is the most likely cause for the variables not being set.

Link: https://lore.kernel.org/oe-kbuild-all/Y6r4mXz5NS0+HVXo@zn.tnic/ [1]
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20230616001631.463536-7-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-08-09 19:33:31 +02:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0
#
# Tests whether a suitable Rust toolchain is available.
set -e
min_tool_version=$(dirname $0)/min-tool-version.sh
# Convert the version string x.y.z to a canonical up-to-7-digits form.
#
# Note that this function uses one more digit (compared to other
# instances in other version scripts) to give a bit more space to
# `rustc` since it will reach 1.100.0 in late 2026.
get_canonical_version()
{
IFS=.
set -- $1
echo $((100000 * $1 + 100 * $2 + $3))
}
# Print a reference to the Quick Start guide in the documentation.
print_docs_reference()
{
echo >&2 "***"
echo >&2 "*** Please see Documentation/rust/quick-start.rst for details"
echo >&2 "*** on how to set up the Rust support."
echo >&2 "***"
}
# Print an explanation about the fact that the script is meant to be called from Kbuild.
print_kbuild_explanation()
{
echo >&2 "***"
echo >&2 "*** This script is intended to be called from Kbuild."
echo >&2 "*** Please use the 'rustavailable' target to call it instead."
echo >&2 "*** Otherwise, the results may not be meaningful."
exit 1
}
# If the script fails for any reason, or if there was any warning, then
# print a reference to the documentation on exit.
warning=0
trap 'if [ $? -ne 0 ] || [ $warning -ne 0 ]; then print_docs_reference; fi' EXIT
# Check that the expected environment variables are set.
if [ -z "${RUSTC+x}" ]; then
echo >&2 "***"
echo >&2 "*** Environment variable 'RUSTC' is not set."
print_kbuild_explanation
fi
if [ -z "${BINDGEN+x}" ]; then
echo >&2 "***"
echo >&2 "*** Environment variable 'BINDGEN' is not set."
print_kbuild_explanation
fi
if [ -z "${CC+x}" ]; then
echo >&2 "***"
echo >&2 "*** Environment variable 'CC' is not set."
print_kbuild_explanation
fi
# Check that the Rust compiler exists.
if ! command -v "$RUSTC" >/dev/null; then
echo >&2 "***"
echo >&2 "*** Rust compiler '$RUSTC' could not be found."
echo >&2 "***"
exit 1
fi
# Check that the Rust bindings generator exists.
if ! command -v "$BINDGEN" >/dev/null; then
echo >&2 "***"
echo >&2 "*** Rust bindings generator '$BINDGEN' could not be found."
echo >&2 "***"
exit 1
fi
# Check that the Rust compiler version is suitable.
#
# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
rust_compiler_version=$( \
LC_ALL=C "$RUSTC" --version 2>/dev/null \
| head -n 1 \
| grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
)
rust_compiler_min_version=$($min_tool_version rustc)
rust_compiler_cversion=$(get_canonical_version $rust_compiler_version)
rust_compiler_min_cversion=$(get_canonical_version $rust_compiler_min_version)
if [ "$rust_compiler_cversion" -lt "$rust_compiler_min_cversion" ]; then
echo >&2 "***"
echo >&2 "*** Rust compiler '$RUSTC' is too old."
echo >&2 "*** Your version: $rust_compiler_version"
echo >&2 "*** Minimum version: $rust_compiler_min_version"
echo >&2 "***"
exit 1
fi
if [ "$rust_compiler_cversion" -gt "$rust_compiler_min_cversion" ]; then
echo >&2 "***"
echo >&2 "*** Rust compiler '$RUSTC' is too new. This may or may not work."
echo >&2 "*** Your version: $rust_compiler_version"
echo >&2 "*** Expected version: $rust_compiler_min_version"
echo >&2 "***"
warning=1
fi
# Check that the Rust bindings generator is suitable.
#
# Non-stable and distributions' versions may have a version suffix, e.g. `-dev`.
rust_bindings_generator_version=$( \
LC_ALL=C "$BINDGEN" --version 2>/dev/null \
| head -n 1 \
| grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
)
rust_bindings_generator_min_version=$($min_tool_version bindgen)
rust_bindings_generator_cversion=$(get_canonical_version $rust_bindings_generator_version)
rust_bindings_generator_min_cversion=$(get_canonical_version $rust_bindings_generator_min_version)
if [ "$rust_bindings_generator_cversion" -lt "$rust_bindings_generator_min_cversion" ]; then
echo >&2 "***"
echo >&2 "*** Rust bindings generator '$BINDGEN' is too old."
echo >&2 "*** Your version: $rust_bindings_generator_version"
echo >&2 "*** Minimum version: $rust_bindings_generator_min_version"
echo >&2 "***"
exit 1
fi
if [ "$rust_bindings_generator_cversion" -gt "$rust_bindings_generator_min_cversion" ]; then
echo >&2 "***"
echo >&2 "*** Rust bindings generator '$BINDGEN' is too new. This may or may not work."
echo >&2 "*** Your version: $rust_bindings_generator_version"
echo >&2 "*** Expected version: $rust_bindings_generator_min_version"
echo >&2 "***"
warning=1
fi
# Check that the `libclang` used by the Rust bindings generator is suitable.
#
# In order to do that, first invoke `bindgen` to get the `libclang` version
# found by `bindgen`. This step may already fail if, for instance, `libclang`
# is not found, thus inform the user in such a case.
bindgen_libclang_output=$( \
LC_ALL=C "$BINDGEN" $(dirname $0)/rust_is_available_bindgen_libclang.h 2>&1 >/dev/null
) || bindgen_libclang_code=$?
if [ -n "$bindgen_libclang_code" ]; then
echo >&2 "***"
echo >&2 "*** Running '$BINDGEN' to check the libclang version (used by the Rust"
echo >&2 "*** bindings generator) failed with code $bindgen_libclang_code. This may be caused by"
echo >&2 "*** a failure to locate libclang. See output and docs below for details:"
echo >&2 "***"
echo >&2 "$bindgen_libclang_output"
echo >&2 "***"
exit 1
fi
# `bindgen` returned successfully, thus use the output to check that the version
# of the `libclang` found by the Rust bindings generator is suitable.
bindgen_libclang_version=$( \
echo "$bindgen_libclang_output" \
| grep -F 'clang version ' \
| grep -oE '[0-9]+\.[0-9]+\.[0-9]+' \
| head -n 1 \
)
bindgen_libclang_min_version=$($min_tool_version llvm)
bindgen_libclang_cversion=$(get_canonical_version $bindgen_libclang_version)
bindgen_libclang_min_cversion=$(get_canonical_version $bindgen_libclang_min_version)
if [ "$bindgen_libclang_cversion" -lt "$bindgen_libclang_min_cversion" ]; then
echo >&2 "***"
echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN') is too old."
echo >&2 "*** Your version: $bindgen_libclang_version"
echo >&2 "*** Minimum version: $bindgen_libclang_min_version"
echo >&2 "***"
exit 1
fi
# If the C compiler is Clang, then we can also check whether its version
# matches the `libclang` version used by the Rust bindings generator.
#
# In the future, we might be able to perform a full version check, see
# https://github.com/rust-lang/rust-bindgen/issues/2138.
cc_name=$($(dirname $0)/cc-version.sh $CC | cut -f1 -d' ')
if [ "$cc_name" = Clang ]; then
clang_version=$( \
LC_ALL=C $CC --version 2>/dev/null \
| sed -nE '1s:.*version ([0-9]+\.[0-9]+\.[0-9]+).*:\1:p'
)
if [ "$clang_version" != "$bindgen_libclang_version" ]; then
echo >&2 "***"
echo >&2 "*** libclang (used by the Rust bindings generator '$BINDGEN')"
echo >&2 "*** version does not match Clang's. This may be a problem."
echo >&2 "*** libclang version: $bindgen_libclang_version"
echo >&2 "*** Clang version: $clang_version"
echo >&2 "***"
warning=1
fi
fi
# Check that the source code for the `core` standard library exists.
#
# `$KRUSTFLAGS` is passed in case the user added `--sysroot`.
rustc_sysroot=$("$RUSTC" $KRUSTFLAGS --print sysroot)
rustc_src=${RUST_LIB_SRC:-"$rustc_sysroot/lib/rustlib/src/rust/library"}
rustc_src_core="$rustc_src/core/src/lib.rs"
if [ ! -e "$rustc_src_core" ]; then
echo >&2 "***"
echo >&2 "*** Source code for the 'core' standard library could not be found"
echo >&2 "*** at '$rustc_src_core'."
echo >&2 "***"
exit 1
fi