keyword-gen.c revision 330141
1/*
2 * keyword-gen.c -- generate keyword scanner finite state machine and
3 *		    keyword_text array.
4 *
5 * This program is run to generate ntp_keyword.h
6 * After making a change here, two output files should be committed at
7 * the same time as keyword-gen.c:
8 *	ntp_keyword.h
9 *	keyword-gen-utd
10 *
11 * keyword-gen-utd is a sentinel used by Makefile.am to avoid compiling
12 * keyword_gen.c and generating ntp_keyword.h if the input keyword-gen.c
13 * has not changed.  This is not solely an optimization, it also breaks
14 * a dependency chain that otherwise would cause programs to be compiled
15 * when running "make dist" or "make distdir".  We want these to package
16 * the existing source without building anything but a tarball.  See
17 * [Bug 1470].
18 */
19#include <config.h>
20#include <stdio.h>
21#include <stdlib.h>
22#include <time.h>
23
24#include <ntp_stdlib.h>
25#include <ntp_config.h>
26#include <lib_strbuf.h>
27#include "ntp_scanner.h"
28#include "ntp_parser.h"
29
30
31/* Define a structure to hold a (keyword, token) pair */
32struct key_tok {
33	char *	key;		/* Keyword */
34	u_short	token;		/* Associated Token */
35	follby	followedby;	/* nonzero indicates the next token(s)
36				   forced to be string(s) */
37};
38
39struct key_tok ntp_keywords[] = {
40{ "...",		T_Ellipsis,		FOLLBY_TOKEN },
41{ "allpeers",		T_Allpeers,		FOLLBY_TOKEN },
42{ "automax",		T_Automax,		FOLLBY_TOKEN },
43{ "broadcast",		T_Broadcast,		FOLLBY_STRING },
44{ "broadcastclient",	T_Broadcastclient,	FOLLBY_TOKEN },
45{ "broadcastdelay",	T_Broadcastdelay,	FOLLBY_TOKEN },
46{ "ctl",		T_Ctl,			FOLLBY_TOKEN },
47{ "disable",		T_Disable,		FOLLBY_TOKEN },
48{ "driftfile",		T_Driftfile,		FOLLBY_STRING },
49{ "dscp",		T_Dscp,			FOLLBY_TOKEN },
50{ "enable",		T_Enable,		FOLLBY_TOKEN },
51{ "end",		T_End,			FOLLBY_TOKEN },
52{ "filegen",		T_Filegen,		FOLLBY_TOKEN },
53{ "fudge",		T_Fudge,		FOLLBY_STRING },
54{ "io",			T_Io,			FOLLBY_TOKEN },
55{ "includefile",	T_Includefile,		FOLLBY_STRING },
56{ "leapfile",		T_Leapfile,		FOLLBY_STRING },
57{ "leapsmearinterval",	T_Leapsmearinterval,	FOLLBY_TOKEN },
58{ "logconfig",		T_Logconfig,		FOLLBY_STRINGS_TO_EOC },
59{ "logfile",		T_Logfile,		FOLLBY_STRING },
60{ "manycastclient",	T_Manycastclient,	FOLLBY_STRING },
61{ "manycastserver",	T_Manycastserver,	FOLLBY_STRINGS_TO_EOC },
62{ "mem",		T_Mem,			FOLLBY_TOKEN },
63{ "multicastclient",	T_Multicastclient,	FOLLBY_STRINGS_TO_EOC },
64{ "peer",		T_Peer,			FOLLBY_STRING },
65{ "phone",		T_Phone,		FOLLBY_STRINGS_TO_EOC },
66{ "pidfile",		T_Pidfile,		FOLLBY_STRING },
67{ "pool",		T_Pool,			FOLLBY_STRING },
68{ "discard",		T_Discard,		FOLLBY_TOKEN },
69{ "reset",		T_Reset,		FOLLBY_TOKEN },
70{ "restrict",		T_Restrict,		FOLLBY_TOKEN },
71{ "rlimit",		T_Rlimit,		FOLLBY_TOKEN },
72{ "server",		T_Server,		FOLLBY_STRING },
73{ "setvar",		T_Setvar,		FOLLBY_STRING },
74{ "statistics",		T_Statistics,		FOLLBY_TOKEN },
75{ "statsdir",		T_Statsdir,		FOLLBY_STRING },
76{ "sys",		T_Sys,			FOLLBY_TOKEN },
77{ "tick",		T_Tick,			FOLLBY_TOKEN },
78{ "timer",		T_Timer,		FOLLBY_TOKEN },
79{ "tinker",		T_Tinker,		FOLLBY_TOKEN },
80{ "tos",		T_Tos,			FOLLBY_TOKEN },
81{ "trap",		T_Trap,			FOLLBY_STRING },
82{ "unconfig",		T_Unconfig,		FOLLBY_STRING },
83{ "unpeer",		T_Unpeer,		FOLLBY_STRING },
84/* authentication_command */
85{ "controlkey",		T_ControlKey,		FOLLBY_TOKEN },
86{ "crypto",		T_Crypto,		FOLLBY_TOKEN },
87{ "keys",		T_Keys,			FOLLBY_STRING },
88{ "keysdir",		T_Keysdir,		FOLLBY_STRING },
89{ "ntpsigndsocket",	T_NtpSignDsocket,	FOLLBY_STRING },
90{ "requestkey",		T_Requestkey,		FOLLBY_TOKEN },
91{ "revoke",		T_Revoke,		FOLLBY_TOKEN },
92{ "trustedkey",		T_Trustedkey,		FOLLBY_TOKEN },
93/* IPv4/IPv6 protocol override flag */
94{ "-4",			T_Ipv4_flag,		FOLLBY_TOKEN },
95{ "-6",			T_Ipv6_flag,		FOLLBY_TOKEN },
96/* option */
97{ "autokey",		T_Autokey,		FOLLBY_TOKEN },
98{ "burst",		T_Burst,		FOLLBY_TOKEN },
99{ "iburst",		T_Iburst,		FOLLBY_TOKEN },
100{ "key",		T_Key,			FOLLBY_TOKEN },
101{ "maxpoll",		T_Maxpoll,		FOLLBY_TOKEN },
102{ "mdnstries",		T_Mdnstries,		FOLLBY_TOKEN },
103{ "minpoll",		T_Minpoll,		FOLLBY_TOKEN },
104{ "mode",		T_Mode,			FOLLBY_TOKEN },
105{ "noselect",		T_Noselect,		FOLLBY_TOKEN },
106{ "preempt",		T_Preempt,		FOLLBY_TOKEN },
107{ "true",		T_True,			FOLLBY_TOKEN },
108{ "prefer",		T_Prefer,		FOLLBY_TOKEN },
109{ "ttl",		T_Ttl,			FOLLBY_TOKEN },
110{ "version",		T_Version,		FOLLBY_TOKEN },
111{ "xleave",		T_Xleave,		FOLLBY_TOKEN },
112/* crypto_command */
113{ "host",		T_Host,			FOLLBY_STRING },
114{ "ident",		T_Ident,		FOLLBY_STRING },
115{ "pw",			T_Pw,			FOLLBY_STRING },
116{ "randfile",		T_Randfile,		FOLLBY_STRING },
117{ "digest",		T_Digest,		FOLLBY_STRING },
118/*** MONITORING COMMANDS ***/
119/* stat */
120{ "clockstats",		T_Clockstats,		FOLLBY_TOKEN },
121{ "cryptostats",	T_Cryptostats,		FOLLBY_TOKEN },
122{ "loopstats",		T_Loopstats,		FOLLBY_TOKEN },
123{ "peerstats",		T_Peerstats,		FOLLBY_TOKEN },
124{ "rawstats",		T_Rawstats,		FOLLBY_TOKEN },
125{ "sysstats", 		T_Sysstats,		FOLLBY_TOKEN },
126{ "protostats",		T_Protostats,		FOLLBY_TOKEN },
127{ "timingstats",	T_Timingstats,		FOLLBY_TOKEN },
128/* filegen_option */
129{ "file",		T_File,			FOLLBY_STRING },
130{ "link",		T_Link,			FOLLBY_TOKEN },
131{ "nolink",		T_Nolink,		FOLLBY_TOKEN },
132{ "type",		T_Type,			FOLLBY_TOKEN },
133/* filegen_type */
134{ "age",		T_Age,			FOLLBY_TOKEN },
135{ "day",		T_Day,			FOLLBY_TOKEN },
136{ "month",		T_Month,		FOLLBY_TOKEN },
137{ "none",		T_None,			FOLLBY_TOKEN },
138{ "pid",		T_Pid,			FOLLBY_TOKEN },
139{ "week",		T_Week,			FOLLBY_TOKEN },
140{ "year",		T_Year,			FOLLBY_TOKEN },
141/*** ORPHAN MODE COMMANDS ***/
142/* tos_option */
143{ "minclock",		T_Minclock,		FOLLBY_TOKEN },
144{ "maxclock",		T_Maxclock,		FOLLBY_TOKEN },
145{ "minsane",		T_Minsane,		FOLLBY_TOKEN },
146{ "floor",		T_Floor,		FOLLBY_TOKEN },
147{ "ceiling",		T_Ceiling,		FOLLBY_TOKEN },
148{ "cohort",		T_Cohort,		FOLLBY_TOKEN },
149{ "mindist",		T_Mindist,		FOLLBY_TOKEN },
150{ "maxdist",		T_Maxdist,		FOLLBY_TOKEN },
151{ "bcpollbstep",	T_Bcpollbstep,		FOLLBY_TOKEN },
152{ "beacon",		T_Beacon,		FOLLBY_TOKEN },
153{ "orphan",		T_Orphan,		FOLLBY_TOKEN },
154{ "orphanwait",		T_Orphanwait,		FOLLBY_TOKEN },
155{ "nonvolatile",	T_Nonvolatile,		FOLLBY_TOKEN },
156{ "basedate",		T_Basedate,		FOLLBY_STRING },
157/* access_control_flag */
158{ "default",		T_Default,		FOLLBY_TOKEN },
159{ "source",		T_Source,		FOLLBY_TOKEN },
160{ "epeer",		T_Epeer,		FOLLBY_TOKEN },
161{ "noepeer",		T_Noepeer,		FOLLBY_TOKEN },
162{ "flake",		T_Flake,		FOLLBY_TOKEN },
163{ "ignore",		T_Ignore,		FOLLBY_TOKEN },
164{ "ippeerlimit",	T_Ippeerlimit,		FOLLBY_TOKEN },
165{ "limited",		T_Limited,		FOLLBY_TOKEN },
166{ "mssntp",		T_Mssntp,		FOLLBY_TOKEN },
167{ "kod",		T_Kod,			FOLLBY_TOKEN },
168{ "lowpriotrap",	T_Lowpriotrap,		FOLLBY_TOKEN },
169{ "mask",		T_Mask,			FOLLBY_TOKEN },
170{ "nomodify",		T_Nomodify,		FOLLBY_TOKEN },
171{ "nomrulist",		T_Nomrulist,		FOLLBY_TOKEN },
172{ "nopeer",		T_Nopeer,		FOLLBY_TOKEN },
173{ "noquery",		T_Noquery,		FOLLBY_TOKEN },
174{ "noserve",		T_Noserve,		FOLLBY_TOKEN },
175{ "notrap",		T_Notrap,		FOLLBY_TOKEN },
176{ "notrust",		T_Notrust,		FOLLBY_TOKEN },
177{ "ntpport",		T_Ntpport,		FOLLBY_TOKEN },
178/* discard_option */
179{ "average",		T_Average,		FOLLBY_TOKEN },
180{ "minimum",		T_Minimum,		FOLLBY_TOKEN },
181{ "monitor",		T_Monitor,		FOLLBY_TOKEN },
182/* mru_option */
183{ "incalloc",		T_Incalloc,		FOLLBY_TOKEN },
184{ "incmem",		T_Incmem,		FOLLBY_TOKEN },
185{ "initalloc",		T_Initalloc,		FOLLBY_TOKEN },
186{ "initmem",		T_Initmem,		FOLLBY_TOKEN },
187{ "mindepth",		T_Mindepth,		FOLLBY_TOKEN },
188{ "maxage",		T_Maxage,		FOLLBY_TOKEN },
189{ "maxdepth",		T_Maxdepth,		FOLLBY_TOKEN },
190{ "maxmem",		T_Maxmem,		FOLLBY_TOKEN },
191{ "mru",		T_Mru,			FOLLBY_TOKEN },
192/* fudge_factor */
193{ "abbrev",		T_Abbrev,		FOLLBY_STRING },
194{ "flag1",		T_Flag1,		FOLLBY_TOKEN },
195{ "flag2",		T_Flag2,		FOLLBY_TOKEN },
196{ "flag3",		T_Flag3,		FOLLBY_TOKEN },
197{ "flag4",		T_Flag4,		FOLLBY_TOKEN },
198{ "refid",		T_Refid,		FOLLBY_STRING },
199{ "stratum",		T_Stratum,		FOLLBY_TOKEN },
200{ "time1",		T_Time1,		FOLLBY_TOKEN },
201{ "time2",		T_Time2,		FOLLBY_TOKEN },
202/* system_option */
203{ "auth",		T_Auth,			FOLLBY_TOKEN },
204{ "bclient",		T_Bclient,		FOLLBY_TOKEN },
205{ "calibrate",		T_Calibrate,		FOLLBY_TOKEN },
206{ "kernel",		T_Kernel,		FOLLBY_TOKEN },
207{ "mode7",		T_Mode7,		FOLLBY_TOKEN },
208{ "ntp",		T_Ntp,			FOLLBY_TOKEN },
209{ "peer_clear_digest_early",	T_PCEdigest,	FOLLBY_TOKEN },
210{ "stats",		T_Stats,		FOLLBY_TOKEN },
211{ "unpeer_crypto_early",	T_UEcrypto,	FOLLBY_TOKEN },
212{ "unpeer_crypto_nak_early",	T_UEcryptonak,	FOLLBY_TOKEN },
213{ "unpeer_digest_early",	T_UEdigest,	FOLLBY_TOKEN },
214/* rlimit_option */
215{ "memlock",		T_Memlock,		FOLLBY_TOKEN },
216{ "stacksize",		T_Stacksize,		FOLLBY_TOKEN },
217{ "filenum",		T_Filenum,		FOLLBY_TOKEN },
218/* tinker_option */
219{ "step",		T_Step,			FOLLBY_TOKEN },
220{ "stepback",		T_Stepback,		FOLLBY_TOKEN },
221{ "stepfwd",		T_Stepfwd,		FOLLBY_TOKEN },
222{ "panic",		T_Panic,		FOLLBY_TOKEN },
223{ "dispersion",		T_Dispersion,		FOLLBY_TOKEN },
224{ "stepout",		T_Stepout,		FOLLBY_TOKEN },
225{ "allan",		T_Allan,		FOLLBY_TOKEN },
226{ "huffpuff",		T_Huffpuff,		FOLLBY_TOKEN },
227{ "freq",		T_Freq,			FOLLBY_TOKEN },
228/* miscellaneous_command */
229{ "port",		T_Port,			FOLLBY_TOKEN },
230{ "interface",		T_Interface,		FOLLBY_TOKEN },
231{ "saveconfigdir",	T_Saveconfigdir,	FOLLBY_STRING },
232/* interface_command (ignore and interface already defined) */
233{ "nic",		T_Nic,			FOLLBY_TOKEN },
234{ "all",		T_All,			FOLLBY_TOKEN },
235{ "ipv4",		T_Ipv4,			FOLLBY_TOKEN },
236{ "ipv6",		T_Ipv6,			FOLLBY_TOKEN },
237{ "wildcard",		T_Wildcard,		FOLLBY_TOKEN },
238{ "listen",		T_Listen,		FOLLBY_TOKEN },
239{ "drop",		T_Drop,			FOLLBY_TOKEN },
240/* simulator commands */
241{ "simulate",		T_Simulate,		FOLLBY_TOKEN },
242{ "simulation_duration",T_Sim_Duration,		FOLLBY_TOKEN },
243{ "beep_delay",		T_Beep_Delay,		FOLLBY_TOKEN },
244{ "duration",		T_Duration,		FOLLBY_TOKEN },
245{ "server_offset",	T_Server_Offset,	FOLLBY_TOKEN },
246{ "freq_offset",	T_Freq_Offset,		FOLLBY_TOKEN },
247{ "wander",		T_Wander,		FOLLBY_TOKEN },
248{ "jitter",		T_Jitter,		FOLLBY_TOKEN },
249{ "prop_delay",		T_Prop_Delay,		FOLLBY_TOKEN },
250{ "proc_delay",		T_Proc_Delay,		FOLLBY_TOKEN },
251};
252
253typedef struct big_scan_state_tag {
254	char	ch;		/* Character this state matches on */
255	char	followedby;	/* Forces next token(s) to T_String */
256	u_short	finishes_token;	/* nonzero ID if last keyword char */
257	u_short	match_next_s;	/* next state to check matching ch */
258	u_short	other_next_s;	/* next state to check if not ch */
259} big_scan_state;
260
261/*
262 * Note: to increase MAXSTATES beyond 2048, be aware it is currently
263 * crammed into 11 bits in scan_state form.  Raising to 4096 would be
264 * relatively easy by storing the followedby value in a separate
265 * array with one entry per token, and shrinking the char value to
266 * 7 bits to free a bit for accepting/non-accepting.  More than 4096
267 * states will require expanding scan_state beyond 32 bits each.
268 */
269#define MAXSTATES	2048
270#define MAX_TOK_LEN	63
271
272const char *	current_keyword;/* for error reporting */
273big_scan_state	sst[MAXSTATES];	/* scanner FSM state entries */
274u_short		sst_highwater;	/* next entry index to consider */
275char *		symb[1024];	/* map token ID to symbolic name */
276
277/* for libntp */
278const char *	progname = "keyword-gen";
279
280int		main			(int, char **);
281static void	generate_preamble	(void);
282static void	generate_fsm		(void);
283static void	generate_token_text	(void);
284static u_short	create_keyword_scanner	(void);
285static u_short	create_scan_states	(char *, u_short, follby, u_short);
286int		compare_key_tok_id	(const void *, const void *);
287int		compare_key_tok_text	(const void *, const void *);
288void		populate_symb		(char *);
289const char *	symbname		(u_short);
290
291
292int main(int argc, char **argv)
293{
294	if (argc < 2) {
295		fprintf(stderr, "Usage:\n%s t_header.h\n", argv[0]);
296		exit(1);
297	}
298	debug = 1;
299
300	populate_symb(argv[1]);
301
302	generate_preamble();
303	generate_token_text();
304	generate_fsm();
305
306	return 0;
307}
308
309
310static void
311generate_preamble(void)
312{
313	time_t now;
314	char timestamp[128];
315	char preamble[] =
316"/*\n"
317" * ntp_keyword.h\n"
318" * \n"
319" * NOTE: edit this file with caution, it is generated by keyword-gen.c\n"
320" *\t Generated %s UTC	  diff_ignore_line\n"
321" *\n"
322" */\n"
323"#include \"ntp_scanner.h\"\n"
324"#include \"ntp_parser.h\"\n"
325"\n";
326
327	time(&now);
328	if (!strftime(timestamp, sizeof(timestamp),
329		      "%Y-%m-%d %H:%M:%S", gmtime(&now)))
330		timestamp[0] = '\0';
331
332	printf(preamble, timestamp);
333}
334
335
336static void
337generate_fsm(void)
338{
339	char rprefix[MAX_TOK_LEN + 1];
340	char prefix[MAX_TOK_LEN + 1];
341	char token_id_comment[16 + MAX_TOK_LEN + 1];
342	size_t prefix_len;
343	char *p;
344	char *r;
345	u_short initial_state;
346	u_short this_state;
347	u_short state;
348	u_short i;
349	u_short token;
350
351	/*
352	 * Sort ntp_keywords in alphabetical keyword order.  This is
353	 * not necessary, but minimizes nonfunctional changes in the
354	 * generated finite state machine when keywords are modified.
355	 */
356	qsort(ntp_keywords, COUNTOF(ntp_keywords),
357	      sizeof(ntp_keywords[0]), compare_key_tok_text);
358
359	/*
360	 * To save space, reserve the state array entry matching each
361	 * token number for its terminal state, so the token identifier
362	 * does not need to be stored in each state, but can be
363	 * recovered trivially.  To mark the entry reserved,
364	 * finishes_token is nonzero.
365	 */
366
367	for (i = 0; i < COUNTOF(ntp_keywords); i++) {
368		token = ntp_keywords[i].token;
369		if (1 > token || token >= COUNTOF(sst)) {
370			fprintf(stderr,
371				"keyword-gen sst[%u] too small "
372				"for keyword '%s' id %d\n",
373				(int)COUNTOF(sst),
374				ntp_keywords[i].key,
375				token);
376			exit(4);
377		}
378		sst[token].finishes_token = token;
379	}
380
381	initial_state = create_keyword_scanner();
382
383	fprintf(stderr,
384		"%d keywords consumed %d states of %d max.\n",
385		(int)COUNTOF(ntp_keywords),
386		sst_highwater - 1,
387		(int)COUNTOF(sst) - 1);
388
389	printf("#define SCANNER_INIT_S %d\n\n", initial_state);
390
391	printf("const scan_state sst[%d] = {\n"
392	       "/*SS_T( ch,\tf-by, match, other ),\t\t\t\t */\n"
393	       "  0,\t\t\t\t      /* %5d %-17s */\n",
394	       sst_highwater,
395	       0, "");
396
397	for (i = 1; i < sst_highwater; i++) {
398
399		/* verify fields will fit */
400		if (sst[i].followedby & ~0x3) {
401			fprintf(stderr,
402				"keyword-gen internal error "
403				"sst[%d].followedby %d too big\n",
404				i, sst[i].followedby);
405			exit(7);
406		}
407
408		if (sst_highwater <= sst[i].match_next_s
409		    || sst[i].match_next_s & ~0x7ff) {
410			fprintf(stderr,
411				"keyword-gen internal error "
412				"sst[%d].match_next_s %d too big\n",
413				i, sst[i].match_next_s);
414			exit(8);
415		}
416
417		if (sst_highwater <= sst[i].other_next_s
418		    || sst[i].other_next_s & ~0x7ff) {
419			fprintf(stderr,
420				"keyword-gen internal error "
421				"sst[%d].other_next_s %d too big\n",
422				i, sst[i].other_next_s);
423			exit(9);
424		}
425
426		if (sst[i].finishes_token) {
427			snprintf(token_id_comment,
428				 sizeof(token_id_comment), "%5d %-17s",
429				 i, symbname(sst[i].finishes_token));
430			if (i != sst[i].finishes_token) {
431				fprintf(stderr,
432					"keyword-gen internal error "
433					"entry %d finishes token %d\n",
434					i, sst[i].finishes_token);
435				exit(5);
436			}
437		} else {
438		/*
439		 * Determine the keyword prefix that leads to this
440		 * state.  This is expensive but keyword-gen is run
441		 * only when it changes.  Distributing keyword-gen-utd
442		 * achieves that, which is why it must be committed
443		 * at the same time as keyword-gen.c and ntp_keyword.h.
444		 *
445		 * Scan the state array iteratively looking for a state
446		 * which leads to the current one, collecting matching
447		 * characters along the way.  There is only one such
448		 * path back to the starting state given the way our
449		 * scanner state machine is built and the practice of
450		 * using the spelling of the keyword as its T_* token
451		 * identifier, which results in never having two
452		 * spellings result in the same T_* value.
453		 */
454			prefix_len = 0;
455			this_state = i;
456			do {
457				for (state = 1; state < sst_highwater; state++)
458					if (sst[state].other_next_s == this_state) {
459						this_state = state;
460						break;
461					} else if (sst[state].match_next_s == this_state) {
462						this_state = state;
463						rprefix[prefix_len] = sst[state].ch;
464						prefix_len++;
465						break;
466					}
467			} while (this_state != initial_state);
468
469			if (prefix_len) {
470				/* reverse rprefix into prefix */
471				p = prefix + prefix_len;
472				r = rprefix;
473				while (r < rprefix + prefix_len)
474					*--p = *r++;
475			}
476			prefix[prefix_len] = '\0';
477
478			snprintf(token_id_comment,
479				 sizeof(token_id_comment), "%5d %-17s",
480				 i, (initial_state == i)
481					? "[initial state]"
482					: prefix);
483		}
484
485		printf("  S_ST( '%c',\t%d,    %5u, %5u )%s /* %s */\n",
486		       sst[i].ch,
487		       sst[i].followedby,
488		       sst[i].match_next_s,
489		       sst[i].other_next_s,
490		       (i + 1 < sst_highwater)
491			   ? ","
492			   : " ",
493		       token_id_comment);
494	}
495
496	printf("};\n\n");
497}
498
499
500/* Define a function to create the states of the scanner. This function
501 * is used by the create_keyword_scanner function below.
502 *
503 * This function takes a suffix of a keyword, the token to be returned on
504 * recognizing the complete keyword, and any pre-existing state that exists
505 * for some other keyword that has the same prefix as the current one.
506 */
507static u_short
508create_scan_states(
509	char *	text,
510	u_short	token,
511	follby	followedby,
512	u_short	prev_state
513	)
514{
515	u_short my_state;
516	u_short return_state;
517	u_short prev_char_s;
518	u_short curr_char_s;
519
520	return_state = prev_state;
521	curr_char_s = prev_state;
522	prev_char_s = 0;
523
524	/* Find the correct position to insert the state.
525	 * All states should be in alphabetical order
526	 */
527	while (curr_char_s && (text[0] < sst[curr_char_s].ch)) {
528		prev_char_s = curr_char_s;
529		curr_char_s = sst[curr_char_s].other_next_s;
530	}
531
532	/*
533	 * Check if a previously seen keyword has the same prefix as
534	 * the current keyword.  If so, simply use the state for that
535	 * keyword as my_state, otherwise, allocate a new state.
536	 */
537	if (curr_char_s && (text[0] == sst[curr_char_s].ch)) {
538		my_state = curr_char_s;
539		if ('\0' == text[1]) {
540			fprintf(stderr,
541				"Duplicate entries for keyword '%s' in"
542				" keyword_gen.c ntp_keywords[].\n",
543				current_keyword);
544			exit(2);
545		}
546	} else {
547		do
548			my_state = sst_highwater++;
549		while (my_state < COUNTOF(sst)
550		       && sst[my_state].finishes_token);
551		if (my_state >= COUNTOF(sst)) {
552			fprintf(stderr,
553				"fatal, keyword scanner state array "
554				"sst[%d] is too small, modify\n"
555				"keyword-gen.c to increase.\n",
556				(int)COUNTOF(sst));
557			exit(3);
558		}
559		/* Store the next character of the keyword */
560		sst[my_state].ch = text[0];
561		sst[my_state].other_next_s = curr_char_s;
562		sst[my_state].followedby = FOLLBY_NON_ACCEPTING;
563
564		if (prev_char_s)
565			sst[prev_char_s].other_next_s = my_state;
566		else
567			return_state = my_state;
568	}
569
570	/* Check if the next character is '\0'.
571	 * If yes, we are done with the recognition and this is an accepting
572	 * state.
573	 * If not, we need to continue scanning
574	 */
575	if ('\0' == text[1]) {
576		sst[my_state].finishes_token = (u_short)token;
577		sst[my_state].followedby = (char)followedby;
578
579		if (sst[token].finishes_token != (u_short)token) {
580			fprintf(stderr,
581				"fatal, sst[%d] not reserved for %s.\n",
582				token, symbname(token));
583			exit(6);
584		}
585		/* relocate so token id is sst[] index */
586		if (my_state != token) {
587			sst[token] = sst[my_state];
588			ZERO(sst[my_state]);
589			do
590				sst_highwater--;
591			while (sst[sst_highwater].finishes_token);
592			my_state = token;
593			if (prev_char_s)
594				sst[prev_char_s].other_next_s = my_state;
595			else
596				return_state = my_state;
597		}
598	} else
599		sst[my_state].match_next_s =
600		    create_scan_states(
601			&text[1],
602			token,
603			followedby,
604			sst[my_state].match_next_s);
605
606	return return_state;
607}
608
609
610/* Define a function that takes a list of (keyword, token) values and
611 * creates a keywords scanner out of it.
612 */
613
614static u_short
615create_keyword_scanner(void)
616{
617	u_short scanner;
618	u_short i;
619
620	sst_highwater = 1;	/* index 0 invalid, unused */
621	scanner = 0;
622
623	for (i = 0; i < COUNTOF(ntp_keywords); i++) {
624		current_keyword = ntp_keywords[i].key;
625		scanner =
626		    create_scan_states(
627			ntp_keywords[i].key,
628			ntp_keywords[i].token,
629			ntp_keywords[i].followedby,
630			scanner);
631	}
632
633	return scanner;
634}
635
636
637static void
638generate_token_text(void)
639{
640	u_short lowest_id;
641	u_short highest_id;
642	u_short id_count;
643	u_short id;
644	u_short i;
645
646	/* sort ntp_keywords in token ID order */
647	qsort(ntp_keywords, COUNTOF(ntp_keywords),
648	      sizeof(ntp_keywords[0]), compare_key_tok_id);
649
650	lowest_id = ntp_keywords[0].token;
651	highest_id = ntp_keywords[COUNTOF(ntp_keywords) - 1].token;
652	id_count = highest_id - lowest_id + 1;
653
654	printf("#define LOWEST_KEYWORD_ID %d\n\n", lowest_id);
655
656	printf("const char * const keyword_text[%d] = {", id_count);
657
658	id = lowest_id;
659	i = 0;
660	while (i < COUNTOF(ntp_keywords)) {
661		while (id < ntp_keywords[i].token) {
662			printf(",\n\t/* %-5d %5d %20s */\tNULL",
663			       id - lowest_id, id, symbname(id));
664			id++;
665		}
666		if (i > 0)
667			printf(",");
668		printf("\n\t/* %-5d %5d %20s */\t\"%s\"",
669		       id - lowest_id, id, symbname(id),
670		       ntp_keywords[i].key);
671		i++;
672		id++;
673	}
674
675	printf("\n};\n\n");
676}
677
678
679int
680compare_key_tok_id(
681	const void *a1,
682	const void *a2
683	)
684{
685	const struct key_tok *p1 = a1;
686	const struct key_tok *p2 = a2;
687
688	if (p1->token == p2->token)
689		return 0;
690
691	if (p1->token < p2->token)
692		return -1;
693	else
694		return 1;
695}
696
697
698int
699compare_key_tok_text(
700	const void *a1,
701	const void *a2
702	)
703{
704	const struct key_tok *p1 = a1;
705	const struct key_tok *p2 = a2;
706
707	return strcmp(p1->key, p2->key);
708}
709
710
711/*
712 * populate_symb() - populate symb[] lookup array with symbolic token
713 *		     names such that symb[T_Age] == "T_Age", etc.
714 */
715void
716populate_symb(
717	char *header_file
718	)
719{
720	FILE *	yh;
721	char	line[2 * MAX_TOK_LEN];
722	char	name[2 * MAX_TOK_LEN];
723	int	token;
724
725	yh = fopen(header_file, "r");
726	if (NULL == yh) {
727		perror("unable to open yacc/bison header file");
728		exit(4);
729	}
730
731	while (NULL != fgets(line, sizeof(line), yh))
732		if (2 == sscanf(line, "#define %s %d", name, &token)
733		    && 'T' == name[0] && '_' == name[1] && token >= 0
734		    && token < COUNTOF(symb)) {
735
736			symb[token] = estrdup(name);
737			if (strlen(name) > MAX_TOK_LEN) {
738				fprintf(stderr,
739					"MAX_TOK_LEN %d too small for '%s'\n"
740					"Edit keyword-gen.c to raise.\n",
741					MAX_TOK_LEN, name);
742				exit(10);
743			}
744		}
745	fclose(yh);
746}
747
748
749const char *
750symbname(
751	u_short token
752	)
753{
754	char *name;
755
756	if (token < COUNTOF(symb) && symb[token] != NULL) {
757		name = symb[token];
758	} else {
759		LIB_GETBUF(name);
760		snprintf(name, LIB_BUFLENGTH, "%d", token);
761	}
762
763	return name;
764}
765