/* search.c - searching subroutines using dfa, kwset and regex for grep. Copyright 1992, 1998, 2000, 2007, 2009 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ /* Written August 1992 by Mike Haertel. */ #ifdef HAVE_CONFIG_H # include #endif #include #include "mbsupport.h" #ifdef MBS_SUPPORT /* We can handle multibyte strings. */ # include # include #endif #include "system.h" #include "grep.h" #ifndef FGREP_PROGRAM # include # include "dfa.h" #endif #include "kwset.h" #include "error.h" #include "xalloc.h" #ifdef HAVE_LIBPCRE # include #endif #define NCHAR (UCHAR_MAX + 1) /* For -w, we also consider _ to be word constituent. */ #define WCHAR(C) (ISALNUM(C) || (C) == '_') /* KWset compiled pattern. For Ecompile and Gcompile, we compile a list of strings, at least one of which is known to occur in any string matching the regexp. */ static kwset_t kwset; static void kwsinit (void) { static char trans[NCHAR]; int i; if (match_icase) for (i = 0; i < NCHAR; ++i) trans[i] = TOLOWER (i); if (!(kwset = kwsalloc (match_icase ? trans : (char *) 0))) error (2, 0, _("memory exhausted")); } #ifndef FGREP_PROGRAM /* DFA compiled regexp. */ static struct dfa dfa; /* The Regex compiled patterns. */ static struct patterns { /* Regex compiled regexp. */ struct re_pattern_buffer regexbuf; struct re_registers regs; /* This is here on account of a BRAIN-DEAD Q@#%!# library interface in regex.c. */ } patterns0; struct patterns *patterns; size_t pcount; void dfaerror (char const *mesg) { error (2, 0, mesg); } /* Number of compiled fixed strings known to exactly match the regexp. If kwsexec returns < kwset_exact_matches, then we don't need to call the regexp matcher at all. */ static int kwset_exact_matches; /* If the DFA turns out to have some set of fixed strings one of which must occur in the match, then we build a kwset matcher to find those strings, and thus quickly filter out impossible matches. */ static void kwsmusts (void) { struct dfamust const *dm; char const *err; if (dfa.musts) { kwsinit (); /* First, we compile in the substrings known to be exact matches. The kwset matcher will return the index of the matching string that it chooses. */ for (dm = dfa.musts; dm; dm = dm->next) { if (!dm->exact) continue; ++kwset_exact_matches; if ((err = kwsincr (kwset, dm->must, strlen (dm->must))) != 0) error (2, 0, err); } /* Now, we compile the substrings that will require the use of the regexp matcher. */ for (dm = dfa.musts; dm; dm = dm->next) { if (dm->exact) continue; if ((err = kwsincr (kwset, dm->must, strlen (dm->must))) != 0) error (2, 0, err); } if ((err = kwsprep (kwset)) != 0) error (2, 0, err); } } #endif /* !FGREP_PROGRAM */ #ifdef MBS_SUPPORT /* This function allocate the array which correspond to "buf". Then this check multibyte string and mark on the positions which are not single byte character nor the first byte of a multibyte character. Caller must free the array. */ static char* check_multibyte_string(char const *buf, size_t size) { char *mb_properties = xmalloc(size); mbstate_t cur_state; wchar_t wc; int i; memset(&cur_state, 0, sizeof(mbstate_t)); memset(mb_properties, 0, sizeof(char)*size); for (i = 0; i < size ;) { size_t mbclen; mbclen = mbrtowc(&wc, buf + i, size - i, &cur_state); if (mbclen == (size_t) -1 || mbclen == (size_t) -2 || mbclen == 0) { /* An invalid sequence, or a truncated multibyte character. We treat it as a single byte character. */ mbclen = 1; } else if (match_icase) { if (iswupper((wint_t)wc)) { wc = towlower((wint_t)wc); wcrtomb(buf + i, wc, &cur_state); } } mb_properties[i] = mbclen; i += mbclen; } return mb_properties; } #endif /* MBS_SUPPORT */ #if defined(GREP_PROGRAM) || defined(EGREP_PROGRAM) #ifdef EGREP_PROGRAM COMPILE_FCT(Ecompile) { reg_syntax_t syntax_bits = RE_SYNTAX_POSIX_EGREP; #else /* No __VA_ARGS__ in C89. So we have to do it this way. */ static COMPILE_RET GEAcompile (char const *pattern, size_t size, reg_syntax_t syntax_bits) { #endif /* EGREP_PROGRAM */ const char *err; const char *sep; size_t total = size; char const *motif = pattern; #if 0 if (match_icase) syntax_bits |= RE_ICASE; #endif re_set_syntax (syntax_bits); dfasyntax (syntax_bits, match_icase, eolbyte); /* For GNU regex compiler we have to pass the patterns separately to detect errors like "[\nallo\n]\n". The patterns here are "[", "allo" and "]" GNU regex should have raise a syntax error. The same for backref, where the backref should have been local to each pattern. */ do { size_t len; sep = memchr (motif, '\n', total); if (sep) { len = sep - motif; sep++; total -= (len + 1); } else { len = total; total = 0; } patterns = realloc (patterns, (pcount + 1) * sizeof (*patterns)); if (patterns == NULL) error (2, errno, _("memory exhausted")); patterns[pcount] = patterns0; if ((err = re_compile_pattern (motif, len, &(patterns[pcount].regexbuf))) != 0) error (2, 0, err); pcount++; motif = sep; } while (sep && total != 0); /* In the match_words and match_lines cases, we use a different pattern for the DFA matcher that will quickly throw out cases that won't work. Then if DFA succeeds we do some hairy stuff using the regex matcher to decide whether the match should really count. */ if (match_words || match_lines) { static char const line_beg_no_bk[] = "^("; static char const line_end_no_bk[] = ")$"; static char const word_beg_no_bk[] = "(^|[^[:alnum:]_])("; static char const word_end_no_bk[] = ")([^[:alnum:]_]|$)"; #ifdef EGREP_PROGRAM # define IF_BK(x, y) (y) char *n = xmalloc (sizeof word_beg_no_bk - 1 + size + sizeof word_end_no_bk); #else static char const line_beg_bk[] = "^\\("; static char const line_end_bk[] = "\\)$"; static char const word_beg_bk[] = "\\(^\\|[^[:alnum:]_]\\)\\("; static char const word_end_bk[] = "\\)\\([^[:alnum:]_]\\|$\\)"; int bk = !(syntax_bits & RE_NO_BK_PARENS); # define IF_BK(x, y) ((bk) ? (x) : (y)) char *n = xmalloc (sizeof word_beg_bk - 1 + size + sizeof word_end_bk); #endif /* EGREP_PROGRAM */ strcpy (n, match_lines ? IF_BK(line_beg_bk, line_beg_no_bk) : IF_BK(word_beg_bk, word_beg_no_bk)); total = strlen(n); memcpy (n + total, pattern, size); total += size; strcpy (n + total, match_lines ? IF_BK(line_end_bk, line_end_no_bk) : IF_BK(word_end_bk, word_end_no_bk)); total += strlen (n + total); pattern = motif = n; size = total; } else motif = NULL; dfacomp (pattern, size, &dfa, 1); kwsmusts (); if (motif) free((char *) motif); } #ifndef EGREP_PROGRAM COMPILE_FCT(Gcompile) { return GEAcompile (pattern, size, RE_SYNTAX_GREP | RE_HAT_LISTS_NOT_NEWLINE); } COMPILE_FCT(Acompile) { return GEAcompile (pattern, size, RE_SYNTAX_AWK); } COMPILE_FCT(Ecompile) { return GEAcompile (pattern, size, RE_SYNTAX_POSIX_EGREP); } #endif /* !EGREP_PROGRAM */ EXECUTE_FCT(EGexecute) { register char const *buflim, *beg, *end, *match, *best_match; char eol = eolbyte; int backref, start, len, best_len; struct kwsmatch kwsm; size_t i, ret_val; #ifdef MBS_SUPPORT char *mb_properties = NULL; if (MB_CUR_MAX > 1) { if (match_icase) { char *case_buf = xmalloc(size); memcpy(case_buf, buf, size); if (start_ptr) start_ptr = case_buf + (start_ptr - buf); buf = case_buf; } if (kwset) mb_properties = check_multibyte_string(buf, size); } #endif /* MBS_SUPPORT */ buflim = buf + size; for (beg = end = buf; end < buflim; beg = end) { if (!start_ptr) { /* We don't care about an exact match. */ if (kwset) { /* Find a possible match using the KWset matcher. */ size_t offset = kwsexec (kwset, beg, buflim - beg, &kwsm); if (offset == (size_t) -1) goto failure; beg += offset; /* Narrow down to the line containing the candidate, and run it through DFA. */ end = memchr(beg, eol, buflim - beg); end++; #ifdef MBS_SUPPORT if (MB_CUR_MAX > 1 && mb_properties[beg - buf] == 0) continue; #endif while (beg > buf && beg[-1] != eol) --beg; if (kwsm.index < kwset_exact_matches) goto success; if (dfaexec (&dfa, beg, end - beg, &backref) == (size_t) -1) continue; } else { /* No good fixed strings; start with DFA. */ size_t offset = dfaexec (&dfa, beg, buflim - beg, &backref); if (offset == (size_t) -1) break; /* Narrow down to the line we've found. */ beg += offset; end = memchr (beg, eol, buflim - beg); end++; while (beg > buf && beg[-1] != eol) --beg; } /* Successful, no backreferences encountered! */ if (!backref) goto success; } else { /* We are looking for the leftmost (then longest) exact match. We will go through the outer loop only once. */ beg = start_ptr; end = buflim; } /* If we've made it to this point, this means DFA has seen a probable match, and we need to run it through Regex. */ best_match = end; best_len = 0; for (i = 0; i < pcount; i++) { patterns[i].regexbuf.not_eol = 0; if (0 <= (start = re_search (&(patterns[i].regexbuf), buf, end - buf - 1, beg - buf, end - beg - 1, &(patterns[i].regs)))) { len = patterns[i].regs.end[0] - start; match = buf + start; if (match > best_match) continue; if (start_ptr && !match_words) goto assess_pattern_match; if ((!match_lines && !match_words) || (match_lines && len == end - beg - 1)) { match = beg; len = end - beg; goto assess_pattern_match; } /* If -w, check if the match aligns with word boundaries. We do this iteratively because: (a) the line may contain more than one occurence of the pattern, and (b) Several alternatives in the pattern might be valid at a given point, and we may need to consider a shorter one to find a word boundary. */ if (match_words) while (match <= best_match) { if ((match == buf || !WCHAR ((unsigned char) match[-1])) && (len == end - beg - 1 || !WCHAR ((unsigned char) match[len]))) goto assess_pattern_match; if (len > 0) { /* Try a shorter length anchored at the same place. */ --len; patterns[i].regexbuf.not_eol = 1; len = re_match (&(patterns[i].regexbuf), buf, match + len - beg, match - buf, &(patterns[i].regs)); } if (len <= 0) { /* Try looking further on. */ if (match == end - 1) break; match++; patterns[i].regexbuf.not_eol = 0; start = re_search (&(patterns[i].regexbuf), buf, end - buf - 1, match - buf, end - match - 1, &(patterns[i].regs)); if (start < 0) break; len = patterns[i].regs.end[0] - start; match = buf + start; } } /* while (match <= best_match) */ continue; assess_pattern_match: if (!start_ptr) { /* Good enough for a non-exact match. No need to look at further patterns, if any. */ beg = match; goto success_in_len; } if (match < best_match || (match == best_match && len > best_len)) { /* Best exact match: leftmost, then longest. */ best_match = match; best_len = len; } } /* if re_search >= 0 */ } /* for Regex patterns. */ if (best_match < end) { /* We have found an exact match. We were just waiting for the best one (leftmost then longest). */ beg = best_match; len = best_len; goto success_in_len; } } /* for (beg = end ..) */ failure: ret_val = -1; goto out; success: len = end - beg; success_in_len: *match_size = len; ret_val = beg - buf; out: #ifdef MBS_SUPPORT if (MB_CUR_MAX > 1) { if (match_icase) free((char*)buf); if (mb_properties) free(mb_properties); } #endif /* MBS_SUPPORT */ return ret_val; } #endif /* defined(GREP_PROGRAM) || defined(EGREP_PROGRAM) */ #if defined(GREP_PROGRAM) || defined(FGREP_PROGRAM) COMPILE_FCT(Fcompile) { char const *beg, *lim, *err; kwsinit (); beg = pattern; do { for (lim = beg; lim < pattern + size && *lim != '\n'; ++lim) ; #if HAVE_DOS_FILE_CONTENTS /* heb */ //--------------------------------------------------------------------------------------- // Try to handle Windows/DOS \r\n pairs as just a \n. // // This function (Fcompile) is called as: // // compile(keys, keycc); // // which becomes: // // Fcompile(pattern,size); // // if the -F option was given or if the program is called 'fgrep' rather than 'grep'. // This means that the patterns are in a file, seperated by newlines. And that is // the problem; newlines are different on different machines (like Windows and Mac). // This "fix" only addresses the case of Windows/DOS machines using ASCII pattern // files. // // This is a ghastly kludge, but for straight ASCII input on a Windows machine // it seems to work. The idea is that if we have just encountered a '\n' char // (as the above for() loop has terminated), then see if it was preceded by a '\r' // char. If so, tell kwsincr() that the string is shorter by 1 than actually found. // // This won't work for multibyte chars and it probably doesn't handle lots of other // cases, but it lets me get by on my Windows box running Cygwin. //--------------------------------------------------------------------------------------- if(((lim - beg) >= 1) && /* must have at least 2 chars to look at */ (*lim == '\n') && /* last one is a normal Unix-style newline char */ (*(lim - 1) == '\r')) /* next-to-last one is a carriage-return char */ { // Indicate string is shorter by 1 if ((err = kwsincr (kwset, beg, (lim - beg) - 1)) != 0) error (2, 0, err); } else { // Normal, non-Windows operation if ((err = kwsincr (kwset, beg, lim - beg)) != 0) error (2, 0, err); } #else // This does not handle Windows/DOS newlines (\r\n instead of \n) if ((err = kwsincr (kwset, beg, lim - beg)) != 0) error (2, 0, err); #endif if (lim < pattern + size) ++lim; beg = lim; } while (beg < pattern + size); if ((err = kwsprep (kwset)) != 0) error (2, 0, err); } EXECUTE_FCT(Fexecute) { register char const *beg, *try, *end; register size_t len; char eol = eolbyte; struct kwsmatch kwsmatch; size_t ret_val; #ifdef MBS_SUPPORT char *mb_properties = NULL; if (MB_CUR_MAX > 1) { if (match_icase) { char *case_buf = xmalloc(size); memcpy(case_buf, buf, size); if (start_ptr) start_ptr = case_buf + (start_ptr - buf); buf = case_buf; } mb_properties = check_multibyte_string(buf, size); } #endif /* MBS_SUPPORT */ for (beg = start_ptr ? start_ptr : buf; beg <= buf + size; beg++) { size_t offset = kwsexec (kwset, beg, buf + size - beg, &kwsmatch); if (offset == (size_t) -1) goto failure; #ifdef MBS_SUPPORT if (MB_CUR_MAX > 1 && mb_properties[offset+beg-buf] == 0) continue; /* It is a part of multibyte character. */ #endif /* MBS_SUPPORT */ beg += offset; len = kwsmatch.size[0]; if (start_ptr && !match_words) goto success_in_beg_and_len; if (match_lines) { if (beg > buf && beg[-1] != eol) continue; if (beg + len < buf + size && beg[len] != eol) continue; goto success; } else if (match_words) for (try = beg; len; ) { if (try > buf && WCHAR((unsigned char) try[-1])) break; if (try + len < buf + size && WCHAR((unsigned char) try[len])) { offset = kwsexec (kwset, beg, --len, &kwsmatch); if (offset == (size_t) -1) break; try = beg + offset; len = kwsmatch.size[0]; } else if (!start_ptr) goto success; else goto success_in_beg_and_len; } /* for (try) */ else goto success; } /* for (beg in buf) */ failure: ret_val = -1; goto out; success: end = memchr (beg + len, eol, (buf + size) - (beg + len)); end++; while (buf < beg && beg[-1] != eol) --beg; len = end - beg; success_in_beg_and_len: *match_size = len; ret_val = beg - buf; out: #ifdef MBS_SUPPORT if (MB_CUR_MAX > 1) { if (match_icase) free((char*)buf); if (mb_properties) free(mb_properties); } #endif /* MBS_SUPPORT */ return ret_val; } #endif /* defined(GREP_PROGRAM) || defined(FGREP_PROGRAM) */ #ifdef GREP_PROGRAM #if HAVE_LIBPCRE /* Compiled internal form of a Perl regular expression. */ static pcre *cre; /* Additional information about the pattern. */ static pcre_extra *extra; #endif COMPILE_FCT(Pcompile) { #if !HAVE_LIBPCRE error (2, 0, "%s", _("Support for the -P option is not compiled into this --disable-perl-regexp binary")); #else int e; char const *ep; char *re = xmalloc (4 * size + 7); int flags = PCRE_MULTILINE | (match_icase ? PCRE_CASELESS : 0); char const *patlim = pattern + size; char *n = re; char const *p; char const *pnul; /* FIXME: Remove these restrictions. */ if (eolbyte != '\n') error (2, 0, _("The -P and -z options cannot be combined")); if (memchr(pattern, '\n', size)) error (2, 0, _("The -P option only supports a single pattern")); *n = '\0'; if (match_lines) strcpy (n, "^("); if (match_words) strcpy (n, "\\b("); n += strlen (n); /* The PCRE interface doesn't allow NUL bytes in the pattern, so replace each NUL byte in the pattern with the four characters "\000", removing a preceding backslash if there are an odd number of backslashes before the NUL. FIXME: This method does not work with some multibyte character encodings, notably Shift-JIS, where a multibyte character can end in a backslash byte. */ for (p = pattern; (pnul = memchr (p, '\0', patlim - p)); p = pnul + 1) { memcpy (n, p, pnul - p); n += pnul - p; for (p = pnul; pattern < p && p[-1] == '\\'; p--) continue; n -= (pnul - p) & 1; strcpy (n, "\\000"); n += 4; } memcpy (n, p, patlim - p); n += patlim - p; *n = '\0'; if (match_words) strcpy (n, ")\\b"); if (match_lines) strcpy (n, ")$"); cre = pcre_compile (re, flags, &ep, &e, pcre_maketables ()); if (!cre) error (2, 0, ep); extra = pcre_study (cre, 0, &ep); if (ep) error (2, 0, ep); free (re); #endif } EXECUTE_FCT(Pexecute) { #if !HAVE_LIBPCRE abort (); return -1; #else /* This array must have at least two elements; everything after that is just for performance improvement in pcre_exec. */ int sub[300]; int e = pcre_exec (cre, extra, buf, size, start_ptr ? (start_ptr - buf) : 0, 0, sub, sizeof sub / sizeof *sub); if (e <= 0) { switch (e) { case PCRE_ERROR_NOMATCH: return -1; case PCRE_ERROR_NOMEMORY: error (2, 0, _("Memory exhausted")); default: abort (); } } else { /* Narrow down to the line we've found. */ char const *beg = buf + sub[0]; char const *end = buf + sub[1]; char const *buflim = buf + size; char eol = eolbyte; if (!start_ptr) { /* FIXME: The case when '\n' is not found indicates a bug: Since grep is line oriented, the match should never contain a newline, so there _must_ be a newline following. */ if (!(end = memchr (end, eol, buflim - end))) end = buflim; else end++; while (buf < beg && beg[-1] != eol) --beg; } *match_size = end - beg; return beg - buf; } #endif } struct matcher const matchers[] = { { "default", Gcompile, EGexecute }, { "grep", Gcompile, EGexecute }, { "egrep", Ecompile, EGexecute }, { "awk", Acompile, EGexecute }, { "fgrep", Fcompile, Fexecute }, { "perl", Pcompile, Pexecute }, { "", 0, 0 }, }; #endif /* GREP_PROGRAM */