4798ffa9e1
Approved by: roberto, delphij Security: VuXML: 0d0f3050-1f69-11e5-9ba9-d050996490d0 Security: http://bugs.ntp.org/show_bug.cgi?id=2853 Security: https://www.kb.cert.org/vuls/id/668167 Security: http://support.ntp.org/bin/view/Main/SecurityNotice#June_2015_NTP_Security_Vulnerabi
143 lines
4.4 KiB
C
143 lines
4.4 KiB
C
/* ntp_scanner.h
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*
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* The header file for a simple lexical analyzer.
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*
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* Written By: Sachin Kamboj
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* University of Delaware
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* Newark, DE 19711
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* Copyright (c) 2006
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*/
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#ifndef NTP_SCANNER_H
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#define NTP_SCANNER_H
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#include "ntp_config.h"
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/*
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* ntp.conf syntax is slightly irregular in that some tokens such as
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* hostnames do not require quoting even if they might otherwise be
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* recognized as T_ terminal tokens. This hand-crafted lexical scanner
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* uses a "followed by" value associated with each keyword to indicate
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* normal scanning of the next token, forced scanning of the next token
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* alone as a T_String, or forced scanning of all tokens to the end of
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* the command as T_String.
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* In the past the identifiers for this functionality ended in _ARG:
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*
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* NO_ARG -> FOLLBY_TOKEN
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* SINGLE_ARG -> FOLLBY_STRING
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* MULTIPLE_ARG -> FOLLBY_STRINGS_TO_EOC
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*
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* Note that some tokens use FOLLBY_TOKEN even though they sometimes
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* are followed by strings. FOLLBY_STRING is used only when needed to
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* avoid the keyword scanner matching a token where a string is needed.
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*
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* FOLLBY_NON_ACCEPT is an overloading of this field to distinguish
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* non-accepting states (where the state number does not match a T_
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* value).
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*/
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typedef enum {
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FOLLBY_TOKEN = 0,
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FOLLBY_STRING,
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FOLLBY_STRINGS_TO_EOC,
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FOLLBY_NON_ACCEPTING
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} follby;
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#define MAXLINE 1024 /* maximum length of line */
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#define MAXINCLUDELEVEL 5 /* maximum include file levels */
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/* STRUCTURES
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* ----------
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*/
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/*
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* Define a structure to hold the FSA for the keywords.
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* The structure is actually a trie.
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*
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* To save space, a single u_int32 encodes four fields, and a fifth
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* (the token completed for terminal states) is implied by the index of
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* the rule within the scan state array, taking advantage of the fact
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* there are more scan states than the highest T_ token number.
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*
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* The lowest 8 bits hold the character the state matches on.
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* Bits 8 and 9 hold the followedby value (0 - 3). For non-accepting
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* states (which do not match a completed token) the followedby
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* value 3 (FOLLBY_NONACCEPTING) denotes that fact. For accepting
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* states, values 0 - 2 control whether the scanner forces the
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* following token(s) to strings.
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* Bits 10 through 20 hold the next state to check not matching
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* this state's character.
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* Bits 21 through 31 hold the next state to check matching the char.
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*/
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#define S_ST(ch, fb, match_n, other_n) ( \
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(u_char)((ch) & 0xff) | \
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((u_int32)(fb) << 8) | \
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((u_int32)(match_n) << 10) | \
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((u_int32)(other_n) << 21) \
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)
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#define SS_CH(ss) ((char)(u_char)((ss) & 0xff))
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#define SS_FB(ss) (((u_int)(ss) >> 8) & 0x3)
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#define SS_MATCH_N(ss) (((u_int)(ss) >> 10) & 0x7ff)
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#define SS_OTHER_N(ss) (((u_int)(ss) >> 21) & 0x7ff)
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typedef u_int32 scan_state;
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struct LCPOS {
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int nline;
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int ncol;
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};
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/* Structure to hold a filename, file pointer and positional info.
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* Instances are dynamically allocated, and the file name is copied by
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* value into a dynamic extension of the 'fname' array. (Which *must* be
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* the last field for that reason!)
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*/
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struct FILE_INFO {
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struct FILE_INFO * st_next; /* next on stack */
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FILE * fpi; /* File Descriptor */
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int force_eof; /* locked or not */
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int backch; /* ungetch buffer */
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struct LCPOS curpos; /* current scan position */
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struct LCPOS bakpos; /* last line end for ungetc */
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struct LCPOS tokpos; /* current token position */
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struct LCPOS errpos; /* error position */
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char fname[1]; /* (formal only) buffered name */
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};
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/* SCANNER GLOBAL VARIABLES
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* ------------------------
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*/
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extern config_tree cfgt; /* Parser output stored here */
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/* VARIOUS EXTERNAL DECLARATIONS
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* -----------------------------
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*/
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extern int old_config_style;
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/* VARIOUS SUBROUTINE DECLARATIONS
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* -------------------------------
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*/
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extern const char *keyword(int token);
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extern char *quote_if_needed(char *str);
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int yylex(void);
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/* managing the input source stack itself */
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extern int/*BOOL*/ lex_init_stack(const char * path, const char * mode);
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extern void lex_drop_stack(void);
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extern int/*BOOL*/ lex_flush_stack(void);
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/* add/remove a nested input source */
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extern int/*BOOL*/ lex_push_file(const char * path, const char * mode);
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extern int/*BOOL*/ lex_pop_file(void);
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/* input stack state query functions */
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extern size_t lex_level(void);
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extern int/*BOOL*/ lex_from_file(void);
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extern struct FILE_INFO * lex_current(void);
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#endif /* NTP_SCANNER_H */
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