ci: Remove handling for the QEMU environment variable

The last uses of this were removed in 201d539 ("Remove OpenBSD CI")
and e88e6b9 ("Move FreeBSD testing from Travis/QEMU to Cirrus-CI"),
so this is no longer needed. Clean up the CI script.

Author: tgross35

ci/run.sh

@@ -5,87 +5,16 @@
 
 set -eux
 
-mirrors_url="https://ci-mirrors.rust-lang.org/libc"
-
 target="$1"
 
 export RUST_BACKTRACE="${RUST_BACKTRACE:-1}"
 
-# If we're going to run tests inside of a qemu image, then we don't need any of
-# the scripts below. Instead, download the image, prepare a filesystem which has
-# the current state of this repository, and then run the image.
-#
-# It's assume that all images, when run with two disks, will run the `run.sh`
-# script from the second which we place inside.
-if [ -n "${QEMU:-}" ]; then
-    tmpdir=/tmp/qemu-img-creation
-    mkdir -p "${tmpdir}"
-
-    if [ -z "${QEMU#*.gz}" ]; then
-        # image is .gz : download and uncompress it
-        base_file="${QEMU%.gz}"
-        pipe_cmd="gunzip -d"
-    elif [ -z "${QEMU#*.xz}" ]; then
-        # image is .xz : download and uncompress it
-        base_file="${QEMU%.xz}"
-        pipe_cmd="unxz"
-    else
-        # plain qcow2 image: just download it
-        base_file="$QEMU"
-        pipe_cmd="cat" # nop to forward the result
-    fi
-
-    qemufile="$(echo "$base_file" | sed 's/\//__/g')"
-    if [ ! -f "${tmpdir}/${qemufile}" ]; then
-        curl --retry 5 "${mirrors_url}/${QEMU}" | $pipe_cmd > "${tmpdir}/${qemufile}"
-    fi
-
-    # Create a mount a fresh new filesystem image that we'll later pass to QEMU.
-    # This will have a `run.sh` script will which use the artifacts inside to run
-    # on the host.
-    rm -f "${tmpdir}/libc-test.img"
-    mkdir "${tmpdir}/mount"
-
-    # Do the standard rigamarole of cross-compiling an executable and then the
-    # script to run just executes the binary.
-    cargo build \
-        --manifest-path libc-test/Cargo.toml \
-        --target "$target" \
-        --test main ${LIBC_CI_ZBUILD_STD+"-Zbuild-std=core"}
-    rm "${CARGO_TARGET_DIR}/${target}"/debug/main-*.d
-    cp "${CARGO_TARGET_DIR}/${target}"/debug/main-* "${tmpdir}"/mount/libc-test
-    # shellcheck disable=SC2016
-    echo 'exec $1/libc-test' > "${tmpdir}/mount/run.sh"
-
-    du -sh "${tmpdir}/mount"
-    genext2fs \
-        --root "${tmpdir}/mount" \
-        --size-in-blocks 100000 \
-        "${tmpdir}/libc-test.img"
-
-    # Pass -snapshot to prevent tampering with the disk images, this helps when
-    # running this script in development. The two drives are then passed next,
-    # first is the OS and second is the one we just made. Next the network is
-    # configured to work (I'm not entirely sure how), and then finally we turn off
-    # graphics and redirect the serial console output to out.log.
-    qemu-system-x86_64 \
-        -m 1024 \
-        -snapshot \
-        -drive if=virtio,file="${tmpdir}/${qemufile}" \
-        -drive if=virtio,file="${tmpdir}/libc-test.img" \
-        -net nic,model=virtio \
-        -net user \
-        -nographic \
-        -vga none 2>&1 | tee "${CARGO_TARGET_DIR}/out.log"
-    exec grep -E "^(PASSED)|(test result: ok)" "${CARGO_TARGET_DIR}/out.log"
-fi
-
 cmd="cargo test --target $target ${LIBC_CI_ZBUILD_STD+"-Zbuild-std"}"
 test_flags="--skip check_style"
 
 # Run tests in the `libc` crate
 case "$target" in
-    # Only run `libc-test` 
+    # Only run `libc-test`
     # FIXME(android): unit tests fail to start on Android
     *android*) cmd="$cmd --manifest-path libc-test/Cargo.toml" ;;
     *s390x*) cmd="$cmd --manifest-path libc-test/Cargo.toml" ;;