/* generate an input file suitable for use by the testbench
 * Copyright (C) 2018-2022 by Rainer Gerhards and Adiscon GmbH.
 * Copyright (C) 2016-2018 by Pascal Withopf and Adiscon GmbH.
 *
 * usage: ./inputfilegen num-lines > file
 * -m number of messages
 * -i start number of message
 * -d extra data to add (all 'X' after the msgnum)
 * -s size of file to generate
 *  cannot be used together with -m
 *  size may be slightly smaller in order to be able to write
 *  the last complete line.
 * -M "message count file" - contains number of messages to be written
 *  This is especially useful with -s, as the testbench otherwise does
 *  not know how to do a seq_check. To keep things flexible, can also be
 *  used with -m (this may aid testbench framework generalization).
 * -f outputfile
 *  Permits to write data to file "outputfile" instead of stdout. Also
 *  enables support for SIGHUP.
 * -S sleep time
 *  ms to sleep between sending message bulks (bulks size given by -B)
 * -B number of messages in bulk
 *  number of messages to send without sleeping as specified in -S.
 *  IGNORED IF -S is not also given!
 * Part of rsyslog, licensed under ASL 2.0
 */
#include "config.h"
#include <stdio.h>
#include <signal.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#if defined(_AIX)
	#include  <unistd.h>
#else
	#include <getopt.h>
#endif
#if defined(__FreeBSD__)
#include <sys/time.h>
#else
#include <time.h>
#endif
#if defined(HAVE_SYS_SELECT_H)
#include <sys/select.h>
#endif

#define DEFMSGS 5
#define NOEXTRADATA -1

static volatile int bHadHUP = 0;
static void
hdlr_sighup(int sig)
{
	fprintf(stderr, "inputfilegen: had hup, sig %d\n", sig);
	bHadHUP = 1;
}
static void
sighup_enable()
{
	struct sigaction sigAct;
	memset(&sigAct, 0, sizeof (sigAct));
	sigemptyset(&sigAct.sa_mask);
	sigAct.sa_handler = hdlr_sighup;
	sigaction(SIGHUP, &sigAct, NULL);
}

void msleep(const int sleepTime)
{
	struct timeval tvSelectTimeout;

	tvSelectTimeout.tv_sec = sleepTime / 1000;
	tvSelectTimeout.tv_usec = (sleepTime % 1000) * 1000; /* micro seconds */
	if(select(0, NULL, NULL, NULL, &tvSelectTimeout) == -1) {
		if(errno != EINTR) {
			perror("select");
			exit(1);
		}
	}
}

static FILE *
open_output(const char *fn)
{
	FILE *fh_output = fopen(fn, "w");
	if(fh_output == NULL) {
		perror(fn);
		exit(1);
	}
	return fh_output;
}

int main(int argc, char* argv[])
{
	int c, i;
	long long nmsgs = DEFMSGS;
	long long nmsgstart = 0;
	int nfinishedidle = 0;
	int nchars = NOEXTRADATA;
	int errflg = 0;
	long long filesize = -1;
	char *extradata = NULL;
	const char *msgcntfile = NULL;
	const char *outputfile = "-";
	FILE *fh_output;
	int sleep_ms = 0;		/* How long to sleep between message writes */
	int sleep_msgs = 0;		/* messages to xmit between sleeps (if configured) */
	int sleep_hubreopen_ms = 5;	/* Wait until new file is being reopened, logrotate may need some time */
	int ctr = 0;

	while((c=getopt(argc, argv, "m:M:i:I:h:d:s:f:S:B:")) != -1) {
		switch(c) {
		case 'm':
			nmsgs = atoi(optarg);
			break;
		case 'M':
			msgcntfile = optarg;
			break;
		case 'i':
			nmsgstart = atoi(optarg);
			break;
		case 'I':
			nfinishedidle = atoi(optarg);
			break;
		case 'd':
			nchars = atoi(optarg);
			break;
		case 's':
			filesize = atoll(optarg);
			break;
		case 'S':
			sleep_ms = atoi(optarg);
			break;
		case 'B':
			sleep_msgs = atoi(optarg);
			break;
		case 'h':
			sleep_hubreopen_ms = atoi(optarg);
			break;
		case 'f':
			outputfile = optarg;
			sighup_enable();
			break;
		case ':':
			fprintf(stderr, "Option -%c requires an operand\n", optopt);
			errflg++;
			break;
		case '?':
			fprintf(stderr, "inputfilegen: Unrecognized option: -%c\n", optopt);
			errflg++;
			break;
		}
	}
	if(errflg) {
		fprintf(stderr, "invalid call\n");
		exit(2);
	}

	if(filesize != -1) {
		const int linesize = (17 + nchars); /* 17 is std line size! */
		nmsgs = filesize / linesize;
		fprintf(stderr, "inputfilegen: file size requested %lld, actual %lld with "
			"%lld lines, %lld bytes less\n",
			filesize, nmsgs * linesize, nmsgs, filesize - nmsgs * linesize);
		if(nmsgs > 100000000) {
			fprintf(stderr, "inputfilegen: number of lines exhaust 8-digit line numbers "
				"which are standard inside the testbench.\n"
				"Use -d switch to add extra data (e.g. -d111 for "
				"128 byte lines or -d47 for 64 byte lines)\n");
			exit(1);
		}
	}

	if(msgcntfile != NULL) {
		FILE *const fh = fopen(msgcntfile, "w");
		if(fh == NULL) {
			perror(msgcntfile);
			exit(1);
		}
		fprintf(fh, "%lld", nmsgs);
		fclose(fh);
	}

	if(strcmp(outputfile, "-")) {
		fh_output = open_output(outputfile);
	} else {
		fh_output = stdout;
	}

	if(nchars != NOEXTRADATA) {
		extradata = (char *)malloc(nchars + 1);
		memset(extradata, 'X', nchars);
		extradata[nchars] = '\0';
	}
	for(i = nmsgstart; i < (nmsgs+nmsgstart); ++i) {
		if(	sleep_ms > 0 &&
			ctr++ >= sleep_msgs) {
			msleep(sleep_ms);
			ctr = 0;
		}
		if(bHadHUP) {
			fclose(fh_output);
			if(sleep_hubreopen_ms > 0) {
				/* Extra Sleep so logrotate or whatever can take place */
				msleep(sleep_hubreopen_ms);
			}
			fh_output = open_output(outputfile);
			fprintf(stderr, "inputfilegen: %s reopened\n", outputfile);
			fprintf(stderr, "inputfilegen: current message number %d\n", i);
			bHadHUP = 0;
		}
		fprintf(fh_output, "msgnum:%8.8d:", i);
		if(nchars != NOEXTRADATA) {
			fprintf(fh_output, "%s", extradata);
		}
		fprintf(fh_output, "\n");
	}
	if (nfinishedidle > 0) {
		/* Keep process open for nfinishedidle ms */
		for(int x = 0; x < nfinishedidle; ++x) {
			if(bHadHUP) {
				/* Create empty file */
				fh_output = open_output(outputfile);
				fclose(fh_output);
				fprintf(stderr, "inputfilegen: last message number was %d\n", i);
				bHadHUP = 0;
			}
			msleep(1);
		}
	}

	free(extradata);
	return 0;
}