1/*	$NetBSD$	*/
2
3/* ntp_scanner.h
4 *
5 * The header file for a simple lexical analyzer.
6 *
7 * Written By:	Sachin Kamboj
8 *		University of Delaware
9 *		Newark, DE 19711
10 * Copyright (c) 2006
11 */
12
13#ifndef NTP_SCANNER_H
14#define NTP_SCANNER_H
15
16/*
17 * ntp.conf syntax is slightly irregular in that some tokens such as
18 * hostnames do not require quoting even if they might otherwise be
19 * recognized as T_ terminal tokens.  This hand-crafted lexical scanner
20 * uses a "followed by" value associated with each keyword to indicate
21 * normal scanning of the next token, forced scanning of the next token
22 * alone as a T_String, or forced scanning of all tokens to the end of
23 * the command as T_String.
24 * In the past the identifiers for this functionality ended in _ARG:
25 *
26 * NO_ARG	->	FOLLBY_TOKEN
27 * SINGLE_ARG	->	FOLLBY_STRING
28 * MULTIPLE_ARG	->	FOLLBY_STRINGS_TO_EOC
29 *
30 * Note that some tokens use FOLLBY_TOKEN even though they sometimes
31 * are followed by strings.  FOLLBY_STRING is used only when needed to
32 * avoid the keyword scanner matching a token where a string is needed.
33 *
34 * FOLLBY_NON_ACCEPT is an overloading of this field to distinguish
35 * non-accepting states (where the state number does not match a T_
36 * value).
37 */
38typedef enum {
39	FOLLBY_TOKEN = 0,
40	FOLLBY_STRING,
41	FOLLBY_STRINGS_TO_EOC,
42	FOLLBY_NON_ACCEPTING
43} follby;
44
45#define MAXLINE		1024	/* maximum length of line */
46#define MAXINCLUDELEVEL	5	/* maximum include file levels */
47
48/* STRUCTURES
49 * ----------
50 */
51
52/*
53 * Define a structure to hold the FSA for the keywords.
54 * The structure is actually a trie.
55 *
56 * To save space, a single u_int32 encodes four fields, and a fifth
57 * (the token completed for terminal states) is implied by the index of
58 * the rule within the scan state array, taking advantage of the fact
59 * there are more scan states than the highest T_ token number.
60 *
61 * The lowest 8 bits hold the character the state matches on.
62 * Bits 8 and 9 hold the followedby value (0 - 3).  For non-accepting
63 *   states (which do not match a completed token) the followedby
64 *   value 3 (FOLLBY_NONACCEPTING) denotes that fact.  For accepting
65 *   states, values 0 - 2 control whether the scanner forces the
66 *   following token(s) to strings.
67 * Bits 10 through 20 hold the next state to check not matching
68 * this state's character.
69 * Bits 21 through 31 hold the next state to check matching the char.
70 */
71
72#define S_ST(ch, fb, match_n, other_n) (			\
73	(u_char)((ch) & 0xff) |					\
74	((u_int32)(fb) << 8) |					\
75	((u_int32)(match_n) << 10) |				\
76	((u_int32)(other_n) << 21)				\
77)
78
79#define SS_CH(ss)	((char)(u_char)((ss) & 0xff))
80#define SS_FB(ss)	(((u_int)(ss) >>  8) & 0x3)
81#define SS_MATCH_N(ss)	(((u_int)(ss) >> 10) & 0x7ff)
82#define SS_OTHER_N(ss)	(((u_int)(ss) >> 21) & 0x7ff)
83
84typedef u_int32 scan_state;
85
86
87/* Structure to hold a filename, file pointer and positional info */
88struct FILE_INFO {
89	const char *	fname;			/* Path to the file */
90	FILE *		fd;			/* File Descriptor */
91	int		line_no;		/* Line Number */
92	int		col_no;			/* Column Number */
93	int		prev_line_col_no;	/* Col No on the
94						   previous line when a
95						   '\n' was seen */
96	int		prev_token_line_no;	/* Line at start of
97						   token */
98	int		prev_token_col_no;	/* Col No at start of
99						   token */
100	int		err_line_no;
101	int		err_col_no;
102};
103
104
105/* SCANNER GLOBAL VARIABLES
106 * ------------------------
107 */
108extern struct config_tree cfgt;	  /* Parser output stored here */
109extern int curr_include_level;    /* The current include level */
110
111extern struct FILE_INFO *ip_file; /* Pointer to the configuration file stream */
112
113/* VARIOUS EXTERNAL DECLARATIONS
114 * -----------------------------
115 */
116extern int old_config_style;
117extern int input_from_file;
118extern struct FILE_INFO *fp[];
119
120/* VARIOUS SUBROUTINE DECLARATIONS
121 * -------------------------------
122 */
123extern const char *keyword(int token);
124extern char *quote_if_needed(char *str);
125int yylex(void);
126
127struct FILE_INFO *F_OPEN(const char *path, const char *mode);
128int FGETC(struct FILE_INFO *stream);
129int UNGETC(int ch, struct FILE_INFO *stream);
130int FCLOSE(struct FILE_INFO *stream);
131
132void push_back_char(int ch);
133
134#endif	/* NTP_SCANNER_H */
135