1 /* $NetBSD: ntp_scanner.h,v 1.1.1.1 2009/12/13 16:56:14 kardel Exp $ */ 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 */ 38 typedef 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 84 typedef u_int32 scan_state; 85 86 87 /* Structure to hold a filename, file pointer and positional info */ 88 struct 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 */ 108 extern struct config_tree cfgt; /* Parser output stored here */ 109 extern int curr_include_level; /* The current include level */ 110 111 extern struct FILE_INFO *ip_file; /* Pointer to the configuration file stream */ 112 113 /* VARIOUS EXTERNAL DECLARATIONS 114 * ----------------------------- 115 */ 116 extern short default_ai_family; 117 extern int old_config_style; 118 extern int input_from_file; 119 extern struct FILE_INFO *fp[]; 120 121 /* VARIOUS SUBROUTINE DECLARATIONS 122 * ------------------------------- 123 */ 124 extern const char *keyword(int token); 125 extern char *quote_if_needed(char *str); 126 int yylex(void); 127 128 struct FILE_INFO *F_OPEN(const char *path, const char *mode); 129 int FGETC(struct FILE_INFO *stream); 130 int UNGETC(int ch, struct FILE_INFO *stream); 131 int FCLOSE(struct FILE_INFO *stream); 132 133 void push_back_char(int ch); 134 135 #endif /* NTP_SCANNER_H */ 136