5f92382c9a
Implementation largely obtained from FreeBSD, with adaptations to meet the needs and style of this sh, some updates to agree with the current POSIX spec, and a few other minor changes. The POSIX spec for this ( http://austingroupbugs.net/view.php?id=249 ) [see note 2809 for the current proposed text] is yet to be approved, so might change. It currently leaves several aspects as unspecified, this implementation handles those as: Where more than 2 hex digits follow \x this implementation processes the first two as hex, the following characters are processed as if the \x sequence was not present. The value obtained from a \nnn octal sequence is truncated to the low 8 bits (if a bigger value is written, eg: \456.) Invalid escape sequences are errors. Invalid \u (or \U) code points are errors if known to be invalid, otherwise can generate a '?' character. Where any escape sequence generates nul ('\0') that char, and the rest of the $'...' string is discarded, but anything remaining in the word is processed, ie: aaa$'bbb\0ccc'ddd produces the same as aaa'bbb'ddd. Differences from FreeBSD: FreeBSD allows only exactly 4 or 8 hex digits for \u and \U (as does C, but the current sh proposal differs.) reeBSD also continues consuming as many hex digits as exist after \x (permitted by the spec, but insane), and reject \u0000 as invalid). Some of this is possibly because that their implementation is based upon an earlier proposal, perhaps note 590 - though that has been updated several times. Differences from the current POSIX proposal: We currently always generate UTF-8 for the \u & \U escapes. We should generate the equivalent character from the current locale's character set (and UTF8 only if that is what the current locale uses.) If anyone would like to correct that, go ahead. We (and FreeBSD) generate (X & 0x1F) for \cX escapes where we should generate the appropriate control character (SOH for \cA for example) with whatever value that has in the current character set. Apart from EBCDIC, which we do not support, I've never seen a case where they differ, so ...
162 lines
6.7 KiB
C
162 lines
6.7 KiB
C
/* $NetBSD: parser.h,v 1.24 2017/08/21 13:20:49 kre Exp $ */
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/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Kenneth Almquist.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)parser.h 8.3 (Berkeley) 5/4/95
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*/
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/* control characters in argument strings */
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#define CTL_FIRST '\201' /* first 'special' character */
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#define CTLESC '\201' /* escape next character */
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#define CTLVAR '\202' /* variable defn */
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#define CTLENDVAR '\203'
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#define CTLBACKQ '\204'
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#define CTLQUOTE 01 /* ored with CTLBACKQ code if in quotes */
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/* CTLBACKQ | CTLQUOTE == '\205' */
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#define CTLARI '\206' /* arithmetic expression */
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#define CTLENDARI '\207'
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#define CTLQUOTEMARK '\210'
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#define CTLQUOTEEND '\211' /* only inside ${...} */
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#define CTLNONL '\212' /* The \n in a deleted \ \n sequence */
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/* pure concidence that (CTLNONL & 0x7f) == '\n' */
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#define CTLCNL '\213' /* A $'\n' - newline not counted */
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#define CTL_LAST '\213' /* last 'special' character */
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/* variable substitution byte (follows CTLVAR) */
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#define VSTYPE 0x0f /* type of variable substitution */
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#define VSNUL 0x10 /* colon--treat the empty string as unset */
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#define VSLINENO 0x20 /* expansion of $LINENO, the line number
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follows immediately */
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#define VSPATQ 0x40 /* ensure correct pattern quoting in ${x#pat} */
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#define VSQUOTE 0x80 /* inside double quotes--suppress splitting */
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/* values of VSTYPE field */
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#define VSNORMAL 0x1 /* normal variable: $var or ${var} */
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#define VSMINUS 0x2 /* ${var-text} */
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#define VSPLUS 0x3 /* ${var+text} */
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#define VSQUESTION 0x4 /* ${var?message} */
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#define VSASSIGN 0x5 /* ${var=text} */
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#define VSTRIMLEFT 0x6 /* ${var#pattern} */
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#define VSTRIMLEFTMAX 0x7 /* ${var##pattern} */
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#define VSTRIMRIGHT 0x8 /* ${var%pattern} */
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#define VSTRIMRIGHTMAX 0x9 /* ${var%%pattern} */
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#define VSLENGTH 0xa /* ${#var} */
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union node *parsecmd(int);
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void fixredir(union node *, const char *, int);
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int goodname(char *);
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const char *getprompt(void *);
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const char *expandstr(char *, int);
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struct HereDoc;
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union node;
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struct nodelist;
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struct parse_state {
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int ps_noalias; /* when set, don't handle aliases */
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struct HereDoc *ps_heredoclist; /* list of here documents to read */
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int ps_parsebackquote; /* nonzero inside backquotes */
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int ps_doprompt; /* if set, prompt the user */
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int ps_needprompt; /* true if interactive at line start */
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int ps_lasttoken; /* last token read */
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int ps_tokpushback; /* last token pushed back */
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char *ps_wordtext; /* text of last word returned by readtoken */
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int ps_checkkwd; /* 1 == check for kwds, 2 += eat newlines */
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struct nodelist *ps_backquotelist; /* list of cmdsubs to process */
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union node *ps_redirnode; /* node for current redirect */
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struct HereDoc *ps_heredoc; /* current heredoc << beign parsed */
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int ps_quoteflag; /* set if (part) of token was quoted */
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int ps_startlinno; /* line # where last token started */
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int ps_funclinno; /* line # of the current function */
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int ps_elided_nl; /* count of \ \n pairs we have seen */
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};
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/*
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* The parser references the elements of struct parse_state quite
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* frequently - they used to be simple globals, so one memory ref
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* per access, adding an indirect through global ptr would not be
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* nice. The following gross hack allows most of that cost to be
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* avoided, by allowing the compiler to understand that the global
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* pointer is in fact constant in any function, and so its value can
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* be cached, rather than needing to be fetched every time in case
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* some other called function has changed it.
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*
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* The rule to make this work is that any function that wants
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* to alter the global must restore it before it returns (and thus
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* must have an error trap handler). That means that the struct
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* used for the new parser state can be a local in that function's
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* stack frame, it never needs to be malloc'd.
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*/
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union parse_state_p {
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struct parse_state *const c_current_parser;
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struct parse_state * v_current_parser;
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};
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extern union parse_state_p psp;
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#define current_parser (psp.c_current_parser)
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/*
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* Perhaps one day emulate "static" by moving most of these definitions into
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* parser.c ... (only checkkwd & tokpushback are used outside parser.c,
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* and only in init.c as a RESET activity)
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*/
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#define tokpushback (current_parser->ps_tokpushback)
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#define checkkwd (current_parser->ps_checkkwd)
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#define noalias (current_parser->ps_noalias)
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#define heredoclist (current_parser->ps_heredoclist)
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#define parsebackquote (current_parser->ps_parsebackquote)
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#define doprompt (current_parser->ps_doprompt)
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#define needprompt (current_parser->ps_needprompt)
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#define lasttoken (current_parser->ps_lasttoken)
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#define wordtext (current_parser->ps_wordtext)
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#define backquotelist (current_parser->ps_backquotelist)
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#define redirnode (current_parser->ps_redirnode)
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#define heredoc (current_parser->ps_heredoc)
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#define quoteflag (current_parser->ps_quoteflag)
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#define startlinno (current_parser->ps_startlinno)
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#define funclinno (current_parser->ps_funclinno)
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#define elided_nl (current_parser->ps_elided_nl)
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/*
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* NEOF is returned by parsecmd when it encounters an end of file. It
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* must be distinct from NULL, so we use the address of a variable that
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* happens to be handy.
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*/
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#define NEOF ((union node *)&psp)
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#ifdef DEBUG
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extern int parsing;
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#endif
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