name : short_splice_read.sh #!/bin/sh # SPDX-License-Identifier: GPL-2.0 # # Test for mishandling of splice() on pseudofilesystems, which should catch # bugs like 11990a5bd7e5 ("module: Correctly truncate sysfs sections output") # # Since splice fallback was removed as part of the set_fs() rework, many of these # tests expect to fail now. See https://lore.kernel.org/lkml/202009181443.C2179FB@keescook/ set -e DIR=$(dirname "$0") ret=0 expect_success() { title="$1" shift echo "" >&2 echo "$title ..." >&2 set +e "$@" rc=$? set -e case "$rc" in 0) echo "ok: $title succeeded" >&2 ;; 1) echo "FAIL: $title should work" >&2 ret=$(( ret + 1 )) ;; *) echo "FAIL: something else went wrong" >&2 ret=$(( ret + 1 )) ;; esac } expect_failure() { title="$1" shift echo "" >&2 echo "$title ..." >&2 set +e "$@" rc=$? set -e case "$rc" in 0) echo "FAIL: $title unexpectedly worked" >&2 ret=$(( ret + 1 )) ;; 1) echo "ok: $title correctly failed" >&2 ;; *) echo "FAIL: something else went wrong" >&2 ret=$(( ret + 1 )) ;; esac } do_splice() { filename="$1" bytes="$2" expected="$3" report="$4" out=$("$DIR"/splice_read "$filename" "$bytes" | cat) if [ "$out" = "$expected" ] ; then echo " matched $report" >&2 return 0 else echo " no match: '$out' vs $report" >&2 return 1 fi } test_splice() { filename="$1" echo " checking $filename ..." >&2 full=$(cat "$filename") rc=$? if [ $rc -ne 0 ] ; then return 2 fi two=$(echo "$full" | grep -m1 . | cut -c-2) # Make sure full splice has the same contents as a standard read. echo " splicing 4096 bytes ..." >&2 if ! do_splice "$filename" 4096 "$full" "full read" ; then return 1 fi # Make sure a partial splice see the first two characters. echo " splicing 2 bytes ..." >&2 if ! do_splice "$filename" 2 "$two" "'$two'" ; then return 1 fi return 0 } ### /proc/$pid/ has no splice interface; these should all fail. expect_failure "proc_single_open(), seq_read() splice" test_splice /proc/$$/limits expect_failure "special open(), seq_read() splice" test_splice /proc/$$/comm ### /proc/sys/ has a splice interface; these should all succeed. expect_success "proc_handler: proc_dointvec_minmax() splice" test_splice /proc/sys/fs/nr_open expect_success "proc_handler: proc_dostring() splice" test_splice /proc/sys/kernel/modprobe expect_success "proc_handler: special read splice" test_splice /proc/sys/kernel/version ### /sys/ has no splice interface; these should all fail. if ! [ -d /sys/module/test_module/sections ] ; then expect_success "test_module kernel module load" modprobe test_module fi expect_success "kernfs attr splice" test_splice /sys/module/test_module/coresize expect_success "kernfs binattr splice" test_splice /sys/module/test_module/sections/.init.text exit $ret