#!/bin/bash
# SPDX-License-Identifier: GPL-2.0-only

set -Eeuo pipefail

# This file generates HAVE_ and NEED_ defines for current kernel
# (or KSRC if provided).
#
# It does so by 'gen' function calls (see body of 'gen-devlink' for examples).
# 'gen' could look for various kinds of declarations in provided kernel headers,
# eg look for an enum in one of files specified and check if given enumeration
# (single value) is present. See 'Documentation' or comment above the 'gen' fun
# in the kcompat-lib.sh.

# Why using bash/awk instead of an old/legacy approach?
#
# The aim is to replicate all the defines provided by human developers
# in the past. Additional bonus is the fact, that we no longer need to care
# about backports done by OS vendors (RHEL, SLES, ORACLE, UBUNTU, more to come).
# We will even work (compile) with only part of backports provided.
#
# To enable smooth transition, especially in time of late fixes, "old" method
# of providing flags should still work as usual.

# End of intro.
# Find info about coding style/rules at the end of file.
# Most of the implementation is in kcompat-lib.sh, here are actual 'gen' calls.

export LC_ALL=C
SCRIPT_DIR="$(dirname "${BASH_SOURCE[0]}")"
ORIG_CWD="$(pwd)"
trap 'rc=$?; echo >&2 "$(realpath "$ORIG_CWD/${BASH_SOURCE[0]}"):$LINENO: failed with rc: $rc"' ERR

# shellcheck source=kcompat-lib.sh
source "$SCRIPT_DIR"/kcompat-lib.sh

# DO NOT break gen calls below (via \), to make our compat code more grep-able,
# keep them also grouped, first by feature (like DEVLINK), then by .h filename
# finally, keep them sorted within a group (sort by flag name)

# handy line of DOC copy-pasted form kcompat-lib.sh:
#   gen DEFINE if (KIND [METHOD of]) NAME [(matches|lacks) PATTERN|absent] in <list-of-files>


function gen-vdpa() {
        vh='include/linux/vdpa.h'
        vm='include/linux/virtio_pci_modern.h'
	if [ -f $vm ];then
		gen HAVE_VIRTIO_PCI_MODERN if struct virtio_pci_modern_device in $vm
	fi
        #gen HAVE_VDPA_OPS_RESET_INFO if method reset of vdpa_config_ops matches lacks status  in "$vh"
        gen HAVE_VDPA_RESET_LACK_INFO if method reset of vdpa_config_ops lacks state  in "$vh"
        gen HAVE_VDPA_OPS_RESET if method reset of vdpa_config_ops  in "$vh"
        gen HAVE_VDPA_ALLOC_LACK_GROUP if fun __vdpa_alloc_device lacks ngroups  in "$vh"
        gen HAVE_VDPA_ALLOC_LACK_NAME if fun __vdpa_alloc_device lacks name  in "$vh"
        gen HAVE_VDPA_VQ_STATE_LACK_PACKED if struct vdpa_vq_state lacks packed in "$vh"    
        gen HAVE_VDPA_MGMTDEV_OPS if struct vdpa_mgmtdev_ops in "$vh"    
        gen HAVE_VDPA_DEV_SET_CONFIG if struct vdpa_dev_set_config in "$vh"    
        gen HAVE_VDPA_OPS_DEVICE_FEAT if method get_device_features of vdpa_config_ops  in "$vh"
        gen HAVE_VDPA_OPS_GET_CONFIG_SIZE if method get_config_size of vdpa_config_ops  in "$vh"
        gen HAVE_VDPA_OPS_LOG_BASE if method set_log_base of vdpa_config_ops  in "$vh"
	gen HAVE_VDPA_OPS_NUM_MIN if method get_vq_num_min of vdpa_config_ops  in "$vh"
}

function gen-aux() {
	ah='include/linux/auxiliary_bus.h'
	mh='include/linux/mod_devicetable.h'
	if config_has CONFIG_AUXILIARY_BUS; then
		gen HAVE_AUXILIARY_DRIVER_INT_REMOVE if method remove of auxiliary_driver matches 'int' in "$ah"
	fi

	# generate HAVE_AUXILIARY_DEVICE_ID only for cases when it's disabled in .config
	if ! config_has CONFIG_AUXILIARY_BUS; then
		gen HAVE_AUXILIARY_DEVICE_ID if struct auxiliary_device_id in "$mh"
	fi
}


function gen-pci() {
	pcih='include/linux/pci.h'
	gen HAVE_PCI_MSIX_ALLOC_IRQ_AT if fun pci_msix_alloc_irq_at in "$pcih"
	gen HAVE_PCI_MSIX_CAN_ALLOC_DYN if fun pci_msix_can_alloc_dyn in "$pcih"
	gen HAVE_PCI_MSIX_FREE_IRQ if fun pci_msix_free_irq in "$pcih"
	gen HAVE_PER_VF_MSIX_SYSFS if method sriov_set_msix_vec_count of pci_driver in "$pcih"
	gen HAVE_STRUCT_PCI_DEV_PTM_ENABLED if struct pci_dev matches ptm_enabled in "$pcih"
	gen NEED_PCIE_FLR if fun pcie_flr absent in "$pcih"
	gen NEED_PCIE_FLR_RETVAL if fun pcie_flr lacks 'int pcie_flr' in "$pcih"
	gen NEED_PCIE_PTM_ENABLED if fun pcie_ptm_enabled absent in "$pcih"
	gen NEED_PCI_ENABLE_PTM if fun pci_enable_ptm absent in "$pcih"
}


# all the generations, extracted from main() to keep normal code and various
# prep separated
function gen-all() {
	# code above is covered by unit_tests/test_gold.sh
	if [ -n "${JUST_UNIT_TESTING-}" ]; then
		return
	fi
	gen-aux
	gen-vdpa
	gen-pci
}

function main() {
	# check if caller (like our makefile) wants to redirect output to file
	if [ -n "${OUT-}" ]; then

		# in case OUT exists, we don't want to overwrite it, instead
		# write to a temporary copy.
		if [ -s "${OUT}" ]; then
			TMP_OUT="$(mktemp "${OUT}.XXX")"
			trap "rm -f '${TMP_OUT}'" EXIT

			REAL_OUT="${OUT}"
			OUT="${TMP_OUT}"
		fi

		exec > "$OUT"
		# all stdout goes to OUT since now
		echo "/* Autogenerated for KSRC=${KSRC-} via $(basename "$0") */"
	fi
	if [ -d "${KSRC-}" ]; then
		cd "${KSRC}"
	fi

	# check if KSRC was ok/if we are in proper place to look for headers
	if [ -z "$(filter-out-bad-files include/linux/kernel.h)" ]; then
		echo >&2 "seems that there are no kernel includes placed in KSRC=${KSRC}
			pwd=$(pwd); ls -l:"
		ls -l >&2
		exit 8
	fi

	# we need some flags from .config or (autoconf.h), required
	if [ ! -f "${CONFFILE-}" ]; then
		echo >&2 ".config should be passed as env CONFFILE
			(and it's not set or not a file)"
		exit 9
	fi

	echo "#ifndef _KCOMPAT_GENERATED_DEFS_H_"
	echo "#define _KCOMPAT_GENERATED_DEFS_H_"
	gen-all
	echo "#endif /* _KCOMPAT_GENERATED_DEFS_H_ */"

	if [ -n "${OUT-}" ]; then
		cd "$ORIG_CWD"

		# Compare and see if anything changed. This avoids updating
		# mtime of the file.
		if [ -n "${REAL_OUT-}" ]; then
			if cmp --silent "${REAL_OUT}" "${TMP_OUT}"; then
				# exit now, skipping print of the output since
				# there were no changes. the trap should
				# cleanup TMP_OUT
				exit 0
			fi

			mv -f "${TMP_OUT}" "${REAL_OUT}"
			OUT="${REAL_OUT}"
		fi

		# dump output, will be visible in CI
		if [ -n "${JUST_UNIT_TESTING-}${QUIET_COMPAT-}" ]; then
			return
		fi
		cat -n "$OUT" >&2
	fi
}

main