/* search.c - searching subroutines using dfa, kwset and regex for grep. Copyright 1992, 1998, 2000 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 2, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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" #include "regex.h" #include "dfa.h" #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) == '_') /* 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; /* 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; /* 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 defined(MBS_SUPPORT) static char* check_multibyte_string PARAMS ((char const *buf, size_t size)); #endif static void kwsinit PARAMS ((void)); static void kwsmusts PARAMS ((void)); static void Gcompile PARAMS ((char const *, size_t)); static void Ecompile PARAMS ((char const *, size_t)); static size_t EGexecute PARAMS ((char const *, size_t, size_t *, int )); static void Fcompile PARAMS ((char const *, size_t)); static size_t Fexecute PARAMS ((char const *, size_t, size_t *, int)); static void Pcompile PARAMS ((char const *, size_t )); static size_t Pexecute PARAMS ((char const *, size_t, size_t *, int)); void dfaerror (char const *mesg) { error (2, 0, mesg); } 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")); } /* 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); } } #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 static void Gcompile (char const *pattern, size_t size) { const char *err; char const *sep; size_t total = size; char const *motif = pattern; re_set_syntax (RE_SYNTAX_GREP | RE_HAT_LISTS_NOT_NEWLINE); dfasyntax (RE_SYNTAX_GREP | RE_HAT_LISTS_NOT_NEWLINE, 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) { /* In the whole-word case, we use the pattern: \(^\|[^[:alnum:]_]\)\(userpattern\)\([^[:alnum:]_]|$\). In the whole-line case, we use the pattern: ^\(userpattern\)$. */ static char const line_beg[] = "^\\("; static char const line_end[] = "\\)$"; static char const word_beg[] = "\\(^\\|[^[:alnum:]_]\\)\\("; static char const word_end[] = "\\)\\([^[:alnum:]_]\\|$\\)"; char *n = xmalloc (sizeof word_beg - 1 + size + sizeof word_end); size_t i; strcpy (n, match_lines ? line_beg : word_beg); i = strlen (n); memcpy (n + i, pattern, size); i += size; strcpy (n + i, match_lines ? line_end : word_end); i += strlen (n + i); pattern = n; size = i; } dfacomp (pattern, size, &dfa, 1); kwsmusts (); } static void Ecompile (char const *pattern, size_t size) { const char *err; const char *sep; size_t total = size; char const *motif = pattern; if (strcmp (matcher, "awk") == 0) { re_set_syntax (RE_SYNTAX_AWK); dfasyntax (RE_SYNTAX_AWK, match_icase, eolbyte); } else { re_set_syntax (RE_SYNTAX_POSIX_EGREP); dfasyntax (RE_SYNTAX_POSIX_EGREP, match_icase, eolbyte); } /* For GNU regex compiler we have to pass the patterns separately to detect errors like "[\nallo\n]\n". The patterns here are "[", "allo" and "]" GNU regex should have raise a syntax error. The same for backref, where the backref should have been local to each pattern. */ do { size_t len; sep = memchr (motif, '\n', total); if (sep) { len = sep - motif; sep++; total -= (len + 1); } else { len = total; total = 0; } patterns = realloc (patterns, (pcount + 1) * sizeof (*patterns)); if (patterns == NULL) error (2, errno, _("memory exhausted")); patterns[pcount] = patterns0; if ((err = re_compile_pattern (motif, len, &(patterns[pcount].regexbuf))) != 0) error (2, 0, err); pcount++; motif = sep; } while (sep && total != 0); /* In the match_words and match_lines cases, we use a different pattern for the DFA matcher that will quickly throw out cases that won't work. Then if DFA succeeds we do some hairy stuff using the regex matcher to decide whether the match should really count. */ if (match_words || match_lines) { /* In the whole-word case, we use the pattern: (^|[^[:alnum:]_])(userpattern)([^[:alnum:]_]|$). In the whole-line case, we use the pattern: ^(userpattern)$. */ static char const line_beg[] = "^("; static char const line_end[] = ")$"; static char const word_beg[] = "(^|[^[:alnum:]_])("; static char const word_end[] = ")([^[:alnum:]_]|$)"; char *n = xmalloc (sizeof word_beg - 1 + size + sizeof word_end); size_t i; strcpy (n, match_lines ? line_beg : word_beg); i = strlen(n); memcpy (n + i, pattern, size); i += size; strcpy (n + i, match_lines ? line_end : word_end); i += strlen (n + i); pattern = n; size = i; } dfacomp (pattern, size, &dfa, 1); kwsmusts (); } static size_t EGexecute (char const *buf, size_t size, size_t *match_size, int exact) { register char const *buflim, *beg, *end; char eol = eolbyte; int backref, start, 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); 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 (!exact) { 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 end = beg + size; /* If we've made it to this point, this means DFA has seen a probable match, and we need to run it through Regex. */ for (i = 0; i < pcount; i++) { patterns[i].regexbuf.not_eol = 0; if (0 <= (start = re_search (&(patterns[i].regexbuf), beg, end - beg - 1, 0, end - beg - 1, &(patterns[i].regs)))) { len = patterns[i].regs.end[0] - start; if (exact) { *match_size = len; return start; } if ((!match_lines && !match_words) || (match_lines && len == end - beg - 1)) goto success; /* 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 (start >= 0) { if ((start == 0 || !WCHAR ((unsigned char) beg[start - 1])) && (len == end - beg - 1 || !WCHAR ((unsigned char) beg[start + len]))) goto success; 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), beg, start + len, start, &(patterns[i].regs)); } if (len <= 0) { /* Try looking further on. */ if (start == end - beg - 1) break; ++start; patterns[i].regexbuf.not_eol = 0; start = re_search (&(patterns[i].regexbuf), beg, end - beg - 1, start, end - beg - 1 - start, &(patterns[i].regs)); len = patterns[i].regs.end[0] - start; } } } } /* for Regex patterns. */ } /* for (beg = end ..) */ failure: #ifdef MBS_SUPPORT if (MB_CUR_MAX > 1) { if (match_icase) free((char*)buf); if (mb_properties) free(mb_properties); } #endif /* MBS_SUPPORT */ return (size_t) -1; success: ret_val = beg - buf; #ifdef MBS_SUPPORT if (MB_CUR_MAX > 1) { if (match_icase) free((char*)buf); if (mb_properties) free(mb_properties); } #endif /* MBS_SUPPORT */ *match_size = end - beg; return ret_val; } static void Fcompile (char const *pattern, size_t size) { char const *beg, *lim, *err; kwsinit (); beg = pattern; do { for (lim = beg; lim < pattern + size && *lim != '\n'; ++lim) ; if ((err = kwsincr (kwset, beg, lim - beg)) != 0) error (2, 0, err); if (lim < pattern + size) ++lim; beg = lim; } while (beg < pattern + size); if ((err = kwsprep (kwset)) != 0) error (2, 0, err); } static size_t Fexecute (char const *buf, size_t size, size_t *match_size, int exact) { 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); buf = case_buf; } mb_properties = check_multibyte_string(buf, size); } #endif /* MBS_SUPPORT */ for (beg = buf; beg <= buf + size; ++beg) { size_t offset = kwsexec (kwset, beg, buf + size - beg, &kwsmatch); if (offset == (size_t) -1) { #ifdef MBS_SUPPORT if (MB_CUR_MAX > 1) { if (match_icase) free ((char*)buf); free(mb_properties); } #endif /* MBS_SUPPORT */ return offset; } #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 (exact) { *match_size = len; ret_val = beg - buf; #ifdef MBS_SUPPORT if (MB_CUR_MAX > 1) { if (match_icase) free ((char*)buf); free(mb_properties); } #endif /* MBS_SUPPORT */ return ret_val; } 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 goto success; } else goto success; } #ifdef MBS_SUPPORT if (MB_CUR_MAX > 1) { if (match_icase) free((char*)buf); if (mb_properties) free(mb_properties); } #endif /* MBS_SUPPORT */ return -1; success: end = memchr (beg + len, eol, (buf + size) - (beg + len)); end++; while (buf < beg && beg[-1] != eol) --beg; *match_size = end - beg; ret_val = beg - buf; #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; } #if HAVE_LIBPCRE /* Compiled internal form of a Perl regular expression. */ static pcre *cre; /* Additional information about the pattern. */ static pcre_extra *extra; #endif static void Pcompile (char const *pattern, size_t size) { #if !HAVE_LIBPCRE error (2, 0, _("The -P option is not supported")); #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 this restriction. */ if (eolbyte != '\n') error (2, 0, _("The -P and -z options cannot be combined")); *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 } static size_t Pexecute (char const *buf, size_t size, size_t *match_size, int exact) { #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, 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 (!exact) { /* 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", Ecompile, EGexecute }, { "fgrep", Fcompile, Fexecute }, { "perl", Pcompile, Pexecute }, { "", 0, 0 }, };