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kernel
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linux
selftests: splice: Check behavior of full and short splices
In order to help catch regressions in splice vs read behavior in certain
special files, test a few with various different kinds of internal
kernel helpers.
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
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tools/testing/selftests/splice/.gitignore
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tools/testing/selftests/splice/.gitignore
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tools/testing/selftests/splice/Makefile
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tools/testing/selftests/splice/Makefile
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# SPDX-License-Identifier: GPL-2.0
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TEST_PROGS := default_file_splice_read.sh
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TEST_GEN_PROGS_EXTENDED := default_file_splice_read
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TEST_PROGS := default_file_splice_read.sh short_splice_read.sh
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TEST_GEN_PROGS_EXTENDED := default_file_splice_read splice_read
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include ../lib.mk
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tools/testing/selftests/splice/config
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tools/testing/selftests/splice/config
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CONFIG_TEST_LKM=m
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tools/testing/selftests/splice/settings
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tools/testing/selftests/splice/settings
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timeout=5
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tools/testing/selftests/splice/short_splice_read.sh
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tools/testing/selftests/splice/short_splice_read.sh
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#!/bin/sh
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# SPDX-License-Identifier: GPL-2.0
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set -e
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ret=0
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do_splice()
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{
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filename="$1"
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bytes="$2"
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expected="$3"
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out=$(./splice_read "$filename" "$bytes" | cat)
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if [ "$out" = "$expected" ] ; then
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echo "ok: $filename $bytes"
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else
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echo "FAIL: $filename $bytes"
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ret=1
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fi
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}
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test_splice()
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{
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filename="$1"
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full=$(cat "$filename")
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two=$(echo "$full" | grep -m1 . | cut -c-2)
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# Make sure full splice has the same contents as a standard read.
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do_splice "$filename" 4096 "$full"
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# Make sure a partial splice see the first two characters.
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do_splice "$filename" 2 "$two"
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}
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# proc_single_open(), seq_read()
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test_splice /proc/$$/limits
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# special open, seq_read()
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test_splice /proc/$$/comm
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# proc_handler, proc_dointvec_minmax
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test_splice /proc/sys/fs/nr_open
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# proc_handler, proc_dostring
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test_splice /proc/sys/kernel/modprobe
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# proc_handler, special read
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test_splice /proc/sys/kernel/version
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if ! [ -d /sys/module/test_module/sections ] ; then
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modprobe test_module
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fi
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# kernfs, attr
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test_splice /sys/module/test_module/coresize
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# kernfs, binattr
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test_splice /sys/module/test_module/sections/.init.text
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exit $ret
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tools/testing/selftests/splice/splice_read.c
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tools/testing/selftests/splice/splice_read.c
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// SPDX-License-Identifier: GPL-2.0
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#define _GNU_SOURCE
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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int main(int argc, char *argv[])
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{
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int fd;
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size_t size;
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ssize_t spliced;
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if (argc < 2) {
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fprintf(stderr, "Usage: %s INPUT [BYTES]\n", argv[0]);
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return EXIT_FAILURE;
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}
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fd = open(argv[1], O_RDONLY);
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if (fd < 0) {
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perror(argv[1]);
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return EXIT_FAILURE;
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}
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if (argc == 3)
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size = atol(argv[2]);
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else {
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struct stat statbuf;
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if (fstat(fd, &statbuf) < 0) {
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perror(argv[1]);
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return EXIT_FAILURE;
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}
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if (statbuf.st_size > INT_MAX) {
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fprintf(stderr, "%s: Too big\n", argv[1]);
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return EXIT_FAILURE;
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}
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size = statbuf.st_size;
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}
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/* splice(2) file to stdout. */
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spliced = splice(fd, NULL, STDOUT_FILENO, NULL,
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size, SPLICE_F_MOVE);
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if (spliced < 0) {
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perror("splice");
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return EXIT_FAILURE;
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}
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close(fd);
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return EXIT_SUCCESS;
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}