#!/bin/bash
# Consistency checks for the system call list
# Copyright (C) 2017-2018 Free Software Foundation, Inc.
# This file is part of the GNU C Library.
#
# The GNU C Library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# The GNU C Library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with the GNU C Library; if not, see
# <http://www.gnu.org/licenses/>.

export LC_ALL=C
set -e
set -o pipefail

if test $# != 4; then
    echo "error: wrong number of arguments: $#"
    exit 1
fi

macros="$1"
list_nr="$2"
list_sys="$3"
GAWK="$4"

linux_version="$("$GAWK" \
  '/#define LINUX_VERSION_CODE / {print $3}' < "$macros")"
glibc_linux_version="$("$GAWK" \
  '/#define __GLIBC_LINUX_VERSION_CODE / {print $3}' < "$macros")"

echo "info: LINUX_VERSION_CODE: $linux_version"
echo "info: __GLIBC_LINUX_VERSION_CODE: $glibc_linux_version"
# Ignore the subrelease in the comparison.
if test $(expr "$glibc_linux_version" / 256) \
        -lt $(expr "$linux_version" / 256); then
    echo "info: The kernel major/minor version is newer than the glibc version"
    kernel_newer=true
else
    kernel_newer=false
fi
echo

errors=0

# Use getpid as a system call which is expected to be always defined.
# alpha uses getxpid instead, so it is permitted as an alternative.
if ! grep -E -q '^getx?pid$' -- "$list_nr"; then
    echo "error: __NR_getpid not defined"
    errors=1
fi
if ! grep -E -q '^getx?pid$' -- "$list_sys"; then
    echo "error: SYS_getpid not defined"
    errors=1
fi

comm_1="$(mktemp)"
comm_2="$(mktemp)"
comm_result="$(mktemp)"
cleanup () {
    rm -f -- "$comm_1" "$comm_2" "$comm_result"
}
trap cleanup 0

sort -o "$comm_1" -- "$list_nr"
sort -o "$comm_2" -- "$list_sys"

# Check for missing SYS_* macros.
comm --check-order -2 -3 -- "$comm_1" "$comm_2" > "$comm_result"
if test -s "$comm_result"; then
    echo "error: These system calls need to be added to syscall-names.list:"
    cat -- "$comm_result"
    # This is only an error if our version is older than the kernel
    # version because we cannot predict future kernel development.
    if $kernel_newer; then
        echo
        echo "warning: This error has been ignored because the glibc"
        echo "warning: system call list is older than the kernel version."
    else
        errors=1
    fi
fi

# Check for additional SYS_* macros.
comm --check-order -1 -3 -- "$comm_1" "$comm_2" > "$comm_result"
if test -s "$comm_result"; then
    echo "error: The following system calls have unexpected SYS_* macros:"
    cat -- "$comm_result"
    errors=1
fi

exit "$errors"