#define  _XOPEN_SOURCE 500	/* needed for nftw() */
#define  _GNU_SOURCE		/* needed for asprintf() */

/* Parse event JSON files */

/*
 * Copyright (c) 2014, Intel Corporation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <stdarg.h>
#include <libgen.h>
#include <dirent.h>
#include <sys/time.h>			/* getrlimit */
#include <sys/resource.h>		/* getrlimit */
#include <ftw.h>
#include <sys/stat.h>
#include "jsmn.h"
#include "json.h"
#include "jevents.h"

#ifndef __maybe_unused
#define __maybe_unused                  __attribute__((unused))
#endif

int verbose;
char *prog;

int eprintf(int level, int var, const char *fmt, ...)
{

	int ret;
	va_list args;

	if (var < level)
		return 0;

	va_start(args, fmt);

	ret = vfprintf(stderr, fmt, args);

	va_end(args);

	return ret;
}

__attribute__((weak)) char *get_cpu_str(void)
{
	return NULL;
}

static void addfield(char *map, char **dst, const char *sep,
		     const char *a, jsmntok_t *bt)
{
	unsigned int len = strlen(a) + 1 + strlen(sep);
	int olen = *dst ? strlen(*dst) : 0;
	int blen = bt ? json_len(bt) : 0;
	char *out;

	out = realloc(*dst, len + olen + blen);
	if (!out) {
		/* Don't add field in this case */
		return;
	}
	*dst = out;

	if (!olen)
		*(*dst) = 0;
	else
		strcat(*dst, sep);
	strcat(*dst, a);
	if (bt)
		strncat(*dst, map + bt->start, blen);
}

static void fixname(char *s)
{
	for (; *s; s++)
		*s = tolower(*s);
}

static void fixdesc(char *s)
{
	char *e = s + strlen(s);

	/* Remove trailing dots that look ugly in perf list */
	--e;
	while (e >= s && isspace(*e))
		--e;
	if (*e == '.')
		*e = 0;
}

static struct msrmap {
	const char *num;
	const char *pname;
} msrmap[] = {
	{ "0x3F6", "ldlat=" },
	{ "0x1A6", "offcore_rsp=" },
	{ "0x1A7", "offcore_rsp=" },
	{ NULL, NULL }
};

static struct field {
	const char *field;
	const char *kernel;
} fields[] = {
	{ "EventCode",	"event=" },
	{ "UMask",	"umask=" },
	{ "CounterMask", "cmask=" },
	{ "Invert",	"inv=" },
	{ "AnyThread",	"any=" },
	{ "EdgeDetect",	"edge=" },
	{ "SampleAfterValue", "period=" },
	{ NULL, NULL }
};

static void cut_comma(char *map, jsmntok_t *newval)
{
	int i;

	/* Cut off everything after comma */
	for (i = newval->start; i < newval->end; i++) {
		if (map[i] == ',')
			newval->end = i;
	}
}

static int match_field(char *map, jsmntok_t *field, int nz,
		       char **event, jsmntok_t *val)
{
	struct field *f;
	jsmntok_t newval = *val;

	for (f = fields; f->field; f++)
		if (json_streq(map, field, f->field) && nz) {
			cut_comma(map, &newval);
			addfield(map, event, ",", f->kernel, &newval);
			return 1;
		}
	return 0;
}

static struct msrmap *lookup_msr(char *map, jsmntok_t *val)
{
	jsmntok_t newval = *val;
	static bool warned;
	int i;

	cut_comma(map, &newval);
	for (i = 0; msrmap[i].num; i++)
		if (json_streq(map, &newval, msrmap[i].num))
			return &msrmap[i];
	if (!warned) {
		warned = true;
		pr_err("%s: Unknown MSR in event file %.*s\n", prog,
			json_len(val), map + val->start);
	}
	return NULL;
}

#define EXPECT(e, t, m) do { if (!(e)) {			\
	jsmntok_t *loc = (t);					\
	if (!(t)->start && (t) > tokens)			\
		loc = (t) - 1;					\
		pr_err("%s:%d: " m ", got %s\n", fn,		\
			json_line(map, loc),			\
			json_name(t));				\
	goto out_free;						\
} } while (0)

#define TOPIC_DEPTH 256
static char *topic_array[TOPIC_DEPTH];
static int   topic_level;

static char *get_topic(void)
{
	char *tp_old, *tp = NULL;
	int i;

	for (i = 0; i < topic_level + 1; i++) {
		int n;

		tp_old = tp;
		n = asprintf(&tp, "%s%s", tp ?: "", topic_array[i]);
		if (n < 0) {
			pr_info("%s: asprintf() error %s\n", prog);
			return NULL;
		}
		free(tp_old);
	}

	for (i = 0; i < (int) strlen(tp); i++) {
		char c = tp[i];

		if (c == '-')
			tp[i] = ' ';
		else if (c == '.') {
			tp[i] = '\0';
			break;
		}
	}

	return tp;
}

static int add_topic(int level, char *bname)
{
	char *topic;

	level -= 2;

	if (level >= TOPIC_DEPTH)
		return -EINVAL;

	topic = strdup(bname);
	if (!topic) {
		pr_info("%s: strdup() error %s for file %s\n", prog,
				strerror(errno), bname);
		return -ENOMEM;
	}

	free(topic_array[topic_level]);
	topic_array[topic_level] = topic;
	topic_level              = level;
	return 0;
}

struct perf_entry_data {
	FILE *outfp;
	char *topic;
};

static int close_table;

static void print_events_table_prefix(FILE *fp, const char *tblname)
{
	fprintf(fp, "struct pmu_event %s[] = {\n", tblname);
	close_table = 1;
}

static int print_events_table_entry(void *data, char *name, char *event,
				    char *desc)
{
	struct perf_entry_data *pd = data;
	FILE *outfp = pd->outfp;
	char *topic = pd->topic;

	/*
	 * TODO: Remove formatting chars after debugging to reduce
	 *	 string lengths.
	 */
	fprintf(outfp, "{\n");

	fprintf(outfp, "\t.name = \"%s\",\n", name);
	fprintf(outfp, "\t.event = \"%s\",\n", event);
	fprintf(outfp, "\t.desc = \"%s\",\n", desc);
	fprintf(outfp, "\t.topic = \"%s\",\n", topic);

	fprintf(outfp, "},\n");

	return 0;
}

static void print_events_table_suffix(FILE *outfp)
{
	fprintf(outfp, "{\n");

	fprintf(outfp, "\t.name = 0,\n");
	fprintf(outfp, "\t.event = 0,\n");
	fprintf(outfp, "\t.desc = 0,\n");

	fprintf(outfp, "},\n");
	fprintf(outfp, "};\n");
	close_table = 0;
}

/* Call func with each event in the json file */
int json_events(const char *fn,
	  int (*func)(void *data, char *name, char *event, char *desc),
	  void *data)
{
	int err = -EIO;
	size_t size;
	jsmntok_t *tokens, *tok;
	int i, j, len;
	char *map;

	if (!fn)
		return -ENOENT;

	tokens = parse_json(fn, &map, &size, &len);
	if (!tokens)
		return -EIO;
	EXPECT(tokens->type == JSMN_ARRAY, tokens, "expected top level array");
	tok = tokens + 1;
	for (i = 0; i < tokens->size; i++) {
		char *event = NULL, *desc = NULL, *name = NULL;
		struct msrmap *msr = NULL;
		jsmntok_t *msrval = NULL;
		jsmntok_t *precise = NULL;
		jsmntok_t *obj = tok++;

		EXPECT(obj->type == JSMN_OBJECT, obj, "expected object");
		for (j = 0; j < obj->size; j += 2) {
			jsmntok_t *field, *val;
			int nz;

			field = tok + j;
			EXPECT(field->type == JSMN_STRING, tok + j,
			       "Expected field name");
			val = tok + j + 1;
			EXPECT(val->type == JSMN_STRING, tok + j + 1,
			       "Expected string value");

			nz = !json_streq(map, val, "0");
			if (match_field(map, field, nz, &event, val)) {
				/* ok */
			} else if (json_streq(map, field, "EventName")) {
				addfield(map, &name, "", "", val);
			} else if (json_streq(map, field, "BriefDescription")) {
				addfield(map, &desc, "", "", val);
				fixdesc(desc);
			} else if (json_streq(map, field, "PEBS") && nz) {
				precise = val;
			} else if (json_streq(map, field, "MSRIndex") && nz) {
				msr = lookup_msr(map, val);
			} else if (json_streq(map, field, "MSRValue")) {
				msrval = val;
			} else if (json_streq(map, field, "Errata") &&
				   !json_streq(map, val, "null")) {
				addfield(map, &desc, ". ",
					" Spec update: ", val);
			} else if (json_streq(map, field, "Data_LA") && nz) {
				addfield(map, &desc, ". ",
					" Supports address when precise",
					NULL);
			}
			/* ignore unknown fields */
		}
		if (precise && desc && !strstr(desc, "(Precise Event)")) {
			if (json_streq(map, precise, "2"))
				addfield(map, &desc, " ", "(Must be precise)",
						NULL);
			else
				addfield(map, &desc, " ",
						"(Precise event)", NULL);
		}
		if (msr != NULL)
			addfield(map, &event, ",", msr->pname, msrval);
		fixname(name);
		err = func(data, name, event, desc);
		free(event);
		free(desc);
		free(name);
		if (err)
			break;
		tok += j;
	}
	EXPECT(tok - tokens == len, tok, "unexpected objects at end");
	err = 0;
out_free:
	free_json(map, size, tokens);
	return err;
}

static char *file_name_to_table_name(char *fname)
{
	unsigned int i;
	int n;
	int c;
	char *tblname;

	/*
	 * Ensure tablename starts with alphabetic character.
	 * Derive rest of table name from basename of the JSON file,
	 * replacing hyphens and stripping out .json suffix.
	 */
	n = asprintf(&tblname, "pme_%s", basename(fname));
	if (n < 0) {
		pr_info("%s: asprintf() error %s for file %s\n", prog,
				strerror(errno), fname);
		return NULL;
	}

	for (i = 0; i < strlen(tblname); i++) {
		c = tblname[i];

		if (c == '-')
			tblname[i] = '_';
		else if (c == '.') {
			tblname[i] = '\0';
			break;
		} else if (!isalnum(c) && c != '_') {
			pr_err("%s: Invalid character '%c' in file name %s\n",
					prog, c, basename(fname));
			free(tblname);
			tblname = NULL;
			break;
		}
	}

	return tblname;
}

static void print_mapping_table_prefix(FILE *outfp)
{
	fprintf(outfp, "struct pmu_events_map pmu_events_map[] = {\n");
}

static void print_mapping_table_suffix(FILE *outfp)
{
	/*
	 * Print the terminating, NULL entry.
	 */
	fprintf(outfp, "{\n");
	fprintf(outfp, "\t.cpuid = 0,\n");
	fprintf(outfp, "\t.version = 0,\n");
	fprintf(outfp, "\t.type = 0,\n");
	fprintf(outfp, "\t.table = 0,\n");
	fprintf(outfp, "},\n");

	/* and finally, the closing curly bracket for the struct */
	fprintf(outfp, "};\n");
}

static int process_mapfile(FILE *outfp, char *fpath)
{
	int n = 16384;
	FILE *mapfp;
	char *save = NULL;
	char *line, *p;
	int line_num;
	char *tblname;

	pr_info("%s: Processing mapfile %s\n", prog, fpath);

	line = malloc(n);
	if (!line)
		return -1;

	mapfp = fopen(fpath, "r");
	if (!mapfp) {
		pr_info("%s: Error %s opening %s\n", prog, strerror(errno),
				fpath);
		return -1;
	}

	print_mapping_table_prefix(outfp);

	line_num = 0;
	while (1) {
		char *cpuid, *version, *type, *fname;

		line_num++;
		p = fgets(line, n, mapfp);
		if (!p)
			break;

		if (line[0] == '#' || line[0] == '\n')
			continue;

		if (line[strlen(line)-1] != '\n') {
			/* TODO Deal with lines longer than 16K */
			pr_info("%s: Mapfile %s: line %d too long, aborting\n",
					prog, fpath, line_num);
			return -1;
		}
		line[strlen(line)-1] = '\0';

		cpuid = strtok_r(p, ",", &save);
		version = strtok_r(NULL, ",", &save);
		fname = strtok_r(NULL, ",", &save);
		type = strtok_r(NULL, ",", &save);

		tblname = file_name_to_table_name(fname);
		fprintf(outfp, "{\n");
		fprintf(outfp, "\t.cpuid = \"%s\",\n", cpuid);
		fprintf(outfp, "\t.version = \"%s\",\n", version);
		fprintf(outfp, "\t.type = \"%s\",\n", type);

		/*
		 * CHECK: We can't use the type (eg "core") field in the
		 * table name. For us to do that, we need to somehow tweak
		 * the other caller of file_name_to_table(), process_json()
		 * to determine the type. process_json() file has no way
		 * of knowing these are "core" events unless file name has
		 * core in it. If filename has core in it, we can safely
		 * ignore the type field here also.
		 */
		fprintf(outfp, "\t.table = %s\n", tblname);
		fprintf(outfp, "},\n");
	}

	print_mapping_table_suffix(outfp);

	return 0;
}

/*
 * If we fail to locate/process JSON and map files, create a NULL mapping
 * table. This would at least allow perf to build even if we can't find/use
 * the aliases.
 */
static void create_empty_mapping(const char *output_file)
{
	FILE *outfp;

	pr_info("%s: Creating empty pmu_events_map[] table\n", prog);

	/* Truncate file to clear any partial writes to it */
	outfp = fopen(output_file, "w");
	if (!outfp) {
		perror("fopen()");
		_Exit(1);
	}

	fprintf(outfp, "#include \"../../pmu-events/pmu-events.h\"\n");
	print_mapping_table_prefix(outfp);
	print_mapping_table_suffix(outfp);
	fclose(outfp);
}

static int get_maxfds(void)
{
	struct rlimit rlim;

	if (getrlimit(RLIMIT_NOFILE, &rlim) == 0)
		return min((int)rlim.rlim_max / 2, 512);

	return 512;
}

/*
 * nftw() doesn't let us pass an argument to the processing function,
 * so use a global variables.
 */
static FILE *eventsfp;
static char *mapfile;

static int process_one_file(const char *fpath, const struct stat *sb,
			    int typeflag, struct FTW *ftwbuf)
{
	char *tblname, *bname  = (char *) fpath + ftwbuf->base;
	int is_dir  = typeflag == FTW_D;
	int is_file = typeflag == FTW_F;
	int level   = ftwbuf->level;
	int err = 0;

	pr_debug("%s %d %7jd %-20s %s\n",
		 is_file ? "f" : is_dir ? "d" : "x",
		 level, sb->st_size, bname, fpath);

	/* base dir */
	if (level == 0)
		return 0;

	/* model directory, reset topic */
	if (level == 1 && is_dir) {
		if (close_table)
			print_events_table_suffix(eventsfp);

		/*
		 * Drop file name suffix. Replace hyphens with underscores.
		 * Fail if file name contains any alphanum characters besides
		 * underscores.
		 */
		tblname = file_name_to_table_name(bname);
		if (!tblname) {
			pr_info("%s: Error determining table name for %s\n", prog,
				bname);
			return -1;
		}

		print_events_table_prefix(eventsfp, tblname);
		return 0;
	}

	/*
	 * Save the mapfile name for now. We will process mapfile
	 * after processing all JSON files (so we can write out the
	 * mapping table after all PMU events tables).
	 *
	 * TODO: Allow for multiple mapfiles? Punt for now.
	 */
	if (level == 1 && is_file) {
		if (!strncmp(bname, "mapfile.csv", 11)) {
			if (mapfile) {
				pr_info("%s: Many mapfiles? Using %s, ignoring %s\n",
						prog, mapfile, fpath);
			} else {
				mapfile = strdup(fpath);
			}
			return 0;
		}

		pr_info("%s: Ignoring file %s\n", prog, fpath);
		return 0;
	}

	/*
	 * If the file name does not have a .json extension,
	 * ignore it. It could be a readme.txt for instance.
	 */
	if (is_file) {
		char *suffix = bname + strlen(bname) - 5;

		if (strncmp(suffix, ".json", 5)) {
			pr_info("%s: Ignoring file without .json suffix %s\n", prog,
				fpath);
			return 0;
		}
	}

	if (level > 1 && add_topic(level, bname))
		return -ENOMEM;

	/*
	 * Assume all other files are JSON files.
	 *
	 * If mapfile refers to 'power7_core.json', we create a table
	 * named 'power7_core'. Any inconsistencies between the mapfile
	 * and directory tree could result in build failure due to table
	 * names not being found.
	 *
	 * Atleast for now, be strict with processing JSON file names.
	 * i.e. if JSON file name cannot be mapped to C-style table name,
	 * fail.
	 */
	if (is_file) {
		struct perf_entry_data data = {
			.topic = get_topic(),
			.outfp = eventsfp,
		};

		err = json_events(fpath, print_events_table_entry, &data);

		free(data.topic);
	}

	return err;
}

#ifndef PATH_MAX
#define PATH_MAX	4096
#endif

/*
 * Starting in directory 'start_dirname', find the "mapfile.csv" and
 * the set of JSON files for the architecture 'arch'.
 *
 * From each JSON file, create a C-style "PMU events table" from the
 * JSON file (see struct pmu_event).
 *
 * From the mapfile, create a mapping between the CPU revisions and
 * PMU event tables (see struct pmu_events_map).
 *
 * Write out the PMU events tables and the mapping table to pmu-event.c.
 *
 * If unable to process the JSON or arch files, create an empty mapping
 * table so we can continue to build/use  perf even if we cannot use the
 * PMU event aliases.
 */
int main(int argc, char *argv[])
{
	int rc;
	int maxfds;
	char ldirname[PATH_MAX];

	const char *arch;
	const char *output_file;
	const char *start_dirname;

	prog = basename(argv[0]);
	if (argc < 4) {
		pr_err("Usage: %s <arch> <starting_dir> <output_file>\n", prog);
		return 1;
	}

	arch = argv[1];
	start_dirname = argv[2];
	output_file = argv[3];

	if (argc > 4)
		verbose = atoi(argv[4]);

	eventsfp = fopen(output_file, "w");
	if (!eventsfp) {
		pr_err("%s Unable to create required file %s (%s)\n",
				prog, output_file, strerror(errno));
		return 2;
	}

	/* Include pmu-events.h first */
	fprintf(eventsfp, "#include \"../../pmu-events/pmu-events.h\"\n");

	sprintf(ldirname, "%s/%s", start_dirname, arch);

	/*
	 * The mapfile allows multiple CPUids to point to the same JSON file,
	 * so, not sure if there is a need for symlinks within the pmu-events
	 * directory.
	 *
	 * For now, treat symlinks of JSON files as regular files and create
	 * separate tables for each symlink (presumably, each symlink refers
	 * to specific version of the CPU).
	 */

	maxfds = get_maxfds();
	mapfile = NULL;
	rc = nftw(ldirname, process_one_file, maxfds, 0);
	if (rc && verbose) {
		pr_info("%s: Error walking file tree %s\n", prog, ldirname);
		goto empty_map;
	} else if (rc) {
		goto empty_map;
	}

	if (close_table)
		print_events_table_suffix(eventsfp);

	if (!mapfile) {
		pr_info("%s: No CPU->JSON mapping?\n", prog);
		goto empty_map;
	}

	if (process_mapfile(eventsfp, mapfile)) {
		pr_info("%s: Error processing mapfile %s\n", prog, mapfile);
		goto empty_map;
	}

	return 0;

empty_map:
	fclose(eventsfp);
	create_empty_mapping(output_file);
	return 0;
}