// SPDX-License-Identifier: Apache-2.0
/*
Copyright (C) 2023 The Falco Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

*/

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <assert.h>

#include <libscap/scap.h>
#include <driver/ppm_events_public.h>
#include <libscap/scap_engines.h>

extern const struct ppm_event_info g_event_info[];


size_t g_get_event_size(ppm_event_code event_type, uint16_t* lens)
{
	uint32_t j;
	int32_t res = 0;

	for(j = 0; j < g_event_info[event_type].nparams; j++)
	{
		res += lens[j];
	}

#ifdef PPM_ENABLE_SENTINEL
	return res + j * sizeof(uint16_t) + sizeof(struct ppm_evt_hdr) + sizeof(uint32_t);
#else
	return res + j * sizeof(uint16_t) + sizeof(struct ppm_evt_hdr);
#endif
}

int32_t g_check_integrity(uint32_t* cur_event, char* copy_buffer, int buf_len, uint32_t* nevents)
{
	uint32_t offset = 0;
	*nevents = 0;

	while(buf_len)
	{
#ifdef PPM_ENABLE_SENTINEL
		uint32_t sentinel_begin;
		uint32_t sentinel_end;
#endif
		struct ppm_evt_hdr* hdr;
		size_t event_size;

		if(buf_len < sizeof(struct ppm_evt_hdr))
		{
			fprintf(stderr, "Error: event not on buffer boundary, offset %x, data to read %d\n",
			        offset,
			        buf_len);
			return SCAP_FAILURE;
		}

		hdr = (struct ppm_evt_hdr*)(copy_buffer + offset);

		uint16_t type = hdr->type;
		if(buf_len < sizeof(struct ppm_evt_hdr) + g_event_info[type].nparams * sizeof(uint16_t))
		{
			fprintf(stderr, "Error: event not on buffer boundary, offset %x, data to read %d\n",
			        offset,
			        buf_len);
			return SCAP_FAILURE;
		}

		event_size = g_get_event_size(hdr->type, (uint16_t*)(copy_buffer + offset + sizeof(struct ppm_evt_hdr)));

		if(event_size == -1)
		{
			fprintf(stderr, "Error: unrecognized event %u, cnt %u, offset %x\n",
			        (uint32_t)(hdr->type),
			        (*cur_event == -1)?0:*cur_event,
			        offset);
			return SCAP_FAILURE;
		}

		if(event_size < sizeof(struct ppm_evt_hdr) + g_event_info[hdr->type].nparams * sizeof(uint16_t))
		{
			fprintf(stderr, "Error: event size too short %u, cnt %u, offset %x\n",
			        (unsigned int)event_size,
			        (*cur_event == -1)?0:*cur_event,
			        offset);
			return SCAP_FAILURE;
		}

#ifdef PPM_ENABLE_SENTINEL
		sentinel_begin = ((struct ppm_evt_hdr*)(copy_buffer + offset))->sentinel_begin;
		sentinel_end = *(uint32_t*)(copy_buffer + offset + event_size - sizeof(uint32_t));

		if(sentinel_begin != sentinel_end)
		{
			fprintf(stderr, "Error: sentinel begin %d, sentinel end %d, evt_type %u, evt_size %zu, cnt %u, offset %x, remaining %u\n",
			        sentinel_begin,
			        sentinel_end,
			        (uint32_t)hdr->type,
			        event_size,
			        (*cur_event == -1)?0:*cur_event,
			        offset,
			        buf_len);
			return SCAP_FAILURE;
		}

		if(*cur_event == -1)
		{
			*cur_event = sentinel_begin;
		}

		if(sentinel_begin != *cur_event)
		{
			fprintf(stderr, "Error1: sentinel begin %d, sentinel end %d, cnt %u, offset %x, remaining %u\n",
			        sentinel_begin,
			        sentinel_end,
			        *cur_event,
			        offset,
			        buf_len);
			return SCAP_FAILURE;
		}
#endif

		buf_len -= event_size;
		offset += event_size;

		++(*nevents);
		++(*cur_event);
	}

	return 0;
}

int main()
{
	uint32_t j;
	char error[SCAP_LASTERR_SIZE];
	int32_t ret;
	char* buf;
	uint32_t buflen;
	uint32_t cur_evts[256];
	int32_t ndevs;
	uint32_t nloops = 0;
	uint64_t totbytes = 0;
	uint64_t totevents = 0;
	uint64_t devicebytes[256];
	uint64_t deviceevents[256];
	uint64_t oldtotbytes = 0;
	uint64_t oldtotevents = 0;
	uint64_t olddevicebytes[256];
	uint64_t olddeviceevents[256];

	/*
		unsigned long new_mask = 1 << (1);
		sched_setaffinity(0,
			sizeof(unsigned long),
			&new_mask);
	*/

	scap_open_args args = {};

	scap_t* h = scap_open(&args, &scap_kmod_engine, error, &ret);
	if(h == NULL)
	{
		fprintf(stderr, "%s (%d)\n", error, ret);
		return ret;
	}

	ndevs = scap_get_ndevs(h);

	if(ndevs > sizeof(cur_evts)/sizeof(cur_evts[0]))
	{
		fprintf(stderr, "too many devices %u\n", ndevs);
		return -1;
	}

	for(j = 0; j < ndevs; j++)
	{
		devicebytes[j] = 0;
		deviceevents[j] = 0;
		olddevicebytes[j] = 0;
		olddeviceevents[j] = 0;
	}

	while(1)
	{
		for(j = 0; j < ndevs; j++)
		{
			uint32_t nevents;

			ret = scap_readbuf(h, j, &buf, &buflen);

			if(ret != SCAP_SUCCESS)
			{
				fprintf(stderr, "%s\n", scap_getlasterr(h));
				scap_close(h);
				return -1;
			}

			cur_evts[j] = -1;

			if(g_check_integrity(&(cur_evts[j]), buf, buflen, &nevents) != SCAP_SUCCESS)
			{
				fprintf(stderr, "Integrity check failure at event %u.\nDumping buffer to dump.bin\n",
				        (cur_evts[j] == -1)?0:cur_evts[j]);

				FILE* f;
				f= fopen("dump.bin", "w");
				fwrite(buf, buflen, 1, f);
				fclose(f);
				exit(-1);
			}

			totbytes += buflen;
			totevents += nevents;
			devicebytes[j] += buflen;
			deviceevents[j] += nevents;

			if(nloops == 1000)
			{
				printf(" %u)bps:%" PRIu64 " totbytes:%" PRIu64 " - evts/s:%" PRIu64 " totevs:%" PRIu64 " \n",
				       j,
				       (devicebytes[j] - olddevicebytes[j]),
				       devicebytes[j],
				       (deviceevents[j] - olddeviceevents[j]),
				       deviceevents[j]);

				olddevicebytes[j] = devicebytes[j];
				olddeviceevents[j] = deviceevents[j];
			}
		}

		//
		// XXX this should check the buffer sizes and sleep only if they are all below a certain
		// threshold.
		//
		usleep(1000);

		if(nloops == 1000)
		{
			scap_stats stats;

			if(scap_get_stats(h, &stats) != SCAP_SUCCESS)
			{
				fprintf(stderr, "%s\n", scap_getlasterr(h));
				scap_close(h);
				return -1;
			}

			printf("bps:%" PRIu64 " totbytes:%" PRIu64 " - evts/s:%" PRIu64 " totevs:%" PRIu64 " drops:%" PRIu64 "\n",
			       totbytes - oldtotbytes,
			       totbytes,
			       totevents - oldtotevents,
			       totevents,
			       stats.n_drops);

			oldtotbytes = totbytes;
			oldtotevents = totevents;

			nloops = 0;
		}

		nloops++;
	}

	scap_close(h);
	return 0;
}
