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+/* exclude.c -- exclude file names
+
+ Copyright (C) 1992-1994, 1997, 1999-2007, 2009-2022 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 of the License, 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, see <https://www.gnu.org/licenses/>. */
+
+/* Written by Paul Eggert <eggert@twinsun.com>
+ and Sergey Poznyakoff <gray@gnu.org>.
+ Thanks to Phil Proudman <phil@proudman51.freeserve.co.uk>
+ for improvement suggestions. */
+
+#include <config.h>
+
+#include <stdbool.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wctype.h>
+#include <regex.h>
+
+#include "exclude.h"
+#include "hash.h"
+#include "mbuiter.h"
+#include "fnmatch.h"
+#include "xalloc.h"
+#include "verify.h"
+#include "filename.h"
+
+#if GNULIB_EXCLUDE_SINGLE_THREAD
+# include "unlocked-io.h"
+#endif
+
+/* Non-GNU systems lack these options, so we don't need to check them. */
+#ifndef FNM_CASEFOLD
+# define FNM_CASEFOLD 0
+#endif
+#ifndef FNM_EXTMATCH
+# define FNM_EXTMATCH 0
+#endif
+#ifndef FNM_LEADING_DIR
+# define FNM_LEADING_DIR 0
+#endif
+
+verify (((EXCLUDE_ANCHORED | EXCLUDE_INCLUDE | EXCLUDE_WILDCARDS)
+ & (FNM_PATHNAME | FNM_NOESCAPE | FNM_PERIOD | FNM_LEADING_DIR
+ | FNM_CASEFOLD | FNM_EXTMATCH))
+ == 0);
+
+
+/* Exclusion patterns are grouped into a singly-linked list of
+ "exclusion segments". Each segment represents a set of patterns
+ that can be matches using the same algorithm. Non-wildcard
+ patterns are kept in hash tables, to speed up searches. Wildcard
+ patterns are stored as arrays of patterns. */
+
+
+/* An exclude pattern-options pair. The options are fnmatch options
+ ORed with EXCLUDE_* options. */
+
+struct patopts
+ {
+ int options;
+ union
+ {
+ char const *pattern;
+ regex_t re;
+ } v;
+ };
+
+/* An array of pattern-options pairs. */
+
+struct exclude_pattern
+ {
+ struct patopts *exclude;
+ idx_t exclude_alloc;
+ idx_t exclude_count;
+ };
+
+enum exclude_type
+ {
+ exclude_hash, /* a hash table of excluded names */
+ exclude_pattern /* an array of exclude patterns */
+ };
+
+struct exclude_segment
+ {
+ struct exclude_segment *next; /* next segment in list */
+ enum exclude_type type; /* type of this segment */
+ int options; /* common options for this segment */
+ union
+ {
+ Hash_table *table; /* for type == exclude_hash */
+ struct exclude_pattern pat; /* for type == exclude_pattern */
+ } v;
+ };
+
+struct pattern_buffer
+ {
+ struct pattern_buffer *next;
+ char *base;
+ };
+
+/* The exclude structure keeps a singly-linked list of exclude segments,
+ maintained in reverse order. */
+struct exclude
+ {
+ struct exclude_segment *head;
+ struct pattern_buffer *patbuf;
+ };
+
+/* Register BUF in the pattern buffer list of EX. ADD_FUNC (see
+ add_exclude_file and add_exclude_fp below) can use this function
+ if it modifies the pattern, to ensure the allocated memory will be
+ properly reclaimed upon calling free_exclude. */
+void
+exclude_add_pattern_buffer (struct exclude *ex, char *buf)
+{
+ struct pattern_buffer *pbuf = xmalloc (sizeof *pbuf);
+ pbuf->base = buf;
+ pbuf->next = ex->patbuf;
+ ex->patbuf = pbuf;
+}
+
+/* Return true if STR has or may have wildcards, when matched with OPTIONS.
+ Return false if STR definitely does not have wildcards. */
+bool
+fnmatch_pattern_has_wildcards (const char *str, int options)
+{
+ while (1)
+ {
+ switch (*str++)
+ {
+ case '.':
+ case '{':
+ case '}':
+ case '(':
+ case ')':
+ if (options & EXCLUDE_REGEX)
+ return true;
+ break;
+
+ case '\\':
+ if (options & EXCLUDE_REGEX)
+ continue;
+ else
+ str += ! (options & FNM_NOESCAPE) && *str;
+ break;
+
+ case '+': case '@': case '!':
+ if (options & FNM_EXTMATCH && *str == '(')
+ return true;
+ break;
+
+ case '?': case '*': case '[':
+ return true;
+
+ case '\0':
+ return false;
+ }
+ }
+}
+
+static void
+unescape_pattern (char *str)
+{
+ char const *q = str;
+ do
+ q += *q == '\\' && q[1];
+ while ((*str++ = *q++));
+}
+
+/* Return a newly allocated and empty exclude list. */
+
+struct exclude *
+new_exclude (void)
+{
+ return xzalloc (sizeof *new_exclude ());
+}
+
+/* Calculate the hash of string. */
+static size_t
+string_hasher (void const *data, size_t n_buckets)
+{
+ char const *p = data;
+ return hash_string (p, n_buckets);
+}
+
+/* Ditto, for case-insensitive hashes */
+static size_t
+string_hasher_ci (void const *data, size_t n_buckets)
+{
+ char const *p = data;
+ mbui_iterator_t iter;
+ size_t value = 0;
+
+ for (mbui_init (iter, p); mbui_avail (iter); mbui_advance (iter))
+ {
+ mbchar_t m = mbui_cur (iter);
+ wchar_t wc;
+
+ if (m.wc_valid)
+ wc = towlower (m.wc);
+ else
+ wc = *m.ptr;
+
+ value = value * 31 + wc;
+ }
+
+ return value % n_buckets;
+}
+
+/* compare two strings for equality */
+static bool
+string_compare (void const *data1, void const *data2)
+{
+ char const *p1 = data1;
+ char const *p2 = data2;
+ return strcmp (p1, p2) == 0;
+}
+
+/* compare two strings for equality, case-insensitive */
+static bool
+string_compare_ci (void const *data1, void const *data2)
+{
+ char const *p1 = data1;
+ char const *p2 = data2;
+ return mbscasecmp (p1, p2) == 0;
+}
+
+static void
+string_free (void *data)
+{
+ free (data);
+}
+
+/* Create new exclude segment of given TYPE and OPTIONS, and attach it
+ to the head of EX. */
+static void
+new_exclude_segment (struct exclude *ex, enum exclude_type type, int options)
+{
+ struct exclude_segment *sp = xzalloc (sizeof (struct exclude_segment));
+ sp->type = type;
+ sp->options = options;
+ switch (type)
+ {
+ case exclude_pattern:
+ break;
+
+ case exclude_hash:
+ sp->v.table = hash_initialize (0, NULL,
+ (options & FNM_CASEFOLD) ?
+ string_hasher_ci
+ : string_hasher,
+ (options & FNM_CASEFOLD) ?
+ string_compare_ci
+ : string_compare,
+ string_free);
+ break;
+ }
+ sp->next = ex->head;
+ ex->head = sp;
+}
+
+/* Free a single exclude segment */
+static void
+free_exclude_segment (struct exclude_segment *seg)
+{
+ switch (seg->type)
+ {
+ case exclude_pattern:
+ for (idx_t i = 0; i < seg->v.pat.exclude_count; i++)
+ {
+ if (seg->v.pat.exclude[i].options & EXCLUDE_REGEX)
+ regfree (&seg->v.pat.exclude[i].v.re);
+ }
+ free (seg->v.pat.exclude);
+ break;
+
+ case exclude_hash:
+ hash_free (seg->v.table);
+ break;
+ }
+ free (seg);
+}
+
+/* Free the storage associated with an exclude list. */
+void
+free_exclude (struct exclude *ex)
+{
+ struct exclude_segment *seg;
+ struct pattern_buffer *pbuf;
+
+ for (seg = ex->head; seg; )
+ {
+ struct exclude_segment *next = seg->next;
+ free_exclude_segment (seg);
+ seg = next;
+ }
+
+ for (pbuf = ex->patbuf; pbuf; )
+ {
+ struct pattern_buffer *next = pbuf->next;
+ free (pbuf->base);
+ free (pbuf);
+ pbuf = next;
+ }
+
+ free (ex);
+}
+
+/* Return zero if PATTERN matches F, obeying OPTIONS, except that
+ (unlike fnmatch) wildcards are disabled in PATTERN. */
+
+static int
+fnmatch_no_wildcards (char const *pattern, char const *f, int options)
+{
+ if (! (options & FNM_LEADING_DIR))
+ return ((options & FNM_CASEFOLD)
+ ? mbscasecmp (pattern, f)
+ : strcmp (pattern, f));
+ else if (! (options & FNM_CASEFOLD))
+ {
+ size_t patlen = strlen (pattern);
+ int r = strncmp (pattern, f, patlen);
+ if (! r)
+ {
+ r = f[patlen];
+ if (r == '/')
+ r = 0;
+ }
+ return r;
+ }
+ else
+ {
+ /* Walk through a copy of F, seeing whether P matches any prefix
+ of F.
+
+ FIXME: This is an O(N**2) algorithm; it should be O(N).
+ Also, the copy should not be necessary. However, fixing this
+ will probably involve a change to the mbs* API. */
+
+ char *fcopy = xstrdup (f);
+ char *p;
+ int r;
+ for (p = fcopy; ; *p++ = '/')
+ {
+ p = strchr (p, '/');
+ if (p)
+ *p = '\0';
+ r = mbscasecmp (pattern, fcopy);
+ if (!p || r <= 0)
+ break;
+ }
+ free (fcopy);
+ return r;
+ }
+}
+
+bool
+exclude_fnmatch (char const *pattern, char const *f, int options)
+{
+ int (*matcher) (char const *, char const *, int) =
+ (options & EXCLUDE_WILDCARDS
+ ? fnmatch
+ : fnmatch_no_wildcards);
+ bool matched = ((*matcher) (pattern, f, options) == 0);
+ char const *p;
+
+ if (! (options & EXCLUDE_ANCHORED))
+ for (p = f; *p && ! matched; p++)
+ if (*p == '/' && p[1] != '/')
+ matched = ((*matcher) (pattern, p + 1, options) == 0);
+
+ return matched;
+}
+
+static bool
+exclude_patopts (struct patopts const *opts, char const *f)
+{
+ int options = opts->options;
+
+ return (options & EXCLUDE_REGEX)
+ ? regexec (&opts->v.re, f, 0, NULL, 0) == 0
+ : exclude_fnmatch (opts->v.pattern, f, options);
+}
+
+/* Return true if the exclude_pattern segment SEG matches F. */
+
+static bool
+file_pattern_matches (struct exclude_segment const *seg, char const *f)
+{
+ idx_t exclude_count = seg->v.pat.exclude_count;
+ struct patopts const *exclude = seg->v.pat.exclude;
+
+ for (idx_t i = 0; i < exclude_count; i++)
+ {
+ if (exclude_patopts (exclude + i, f))
+ return true;
+ }
+ return false;
+}
+
+/* Return true if the exclude_hash segment SEG matches F.
+ BUFFER is an auxiliary storage of the same length as F (with nul
+ terminator included) */
+static bool
+file_name_matches (struct exclude_segment const *seg, char const *f,
+ char *buffer)
+{
+ int options = seg->options;
+ Hash_table *table = seg->v.table;
+
+ do
+ {
+ /* initialize the pattern */
+ strcpy (buffer, f);
+
+ while (1)
+ {
+ if (hash_lookup (table, buffer))
+ return true;
+ if (options & FNM_LEADING_DIR)
+ {
+ char *p = strrchr (buffer, '/');
+ if (p)
+ {
+ *p = 0;
+ continue;
+ }
+ }
+ break;
+ }
+
+ if (!(options & EXCLUDE_ANCHORED))
+ {
+ f = strchr (f, '/');
+ if (f)
+ f++;
+ }
+ else
+ break;
+ }
+ while (f);
+
+ return false;
+}
+
+/* Return true if EX excludes F. */
+
+bool
+excluded_file_name (struct exclude const *ex, char const *f)
+{
+ struct exclude_segment *seg;
+ bool invert = false;
+ char *filename = NULL;
+
+ /* If no patterns are given, the default is to include. */
+ if (!ex->head)
+ return false;
+
+ /* Scan through the segments, reporting the status of the first match.
+ The segments are in reverse order, so this reports the status of
+ the last match in the original option list. */
+ for (seg = ex->head; ; seg = seg->next)
+ {
+ if (seg->type == exclude_hash)
+ {
+ if (!filename)
+ filename = xmalloc (strlen (f) + 1);
+ if (file_name_matches (seg, f, filename))
+ break;
+ }
+ else
+ {
+ if (file_pattern_matches (seg, f))
+ break;
+ }
+
+ if (! seg->next)
+ {
+ /* If patterns are given but none match, the default is the
+ opposite of the last segment (i.e., the first in the
+ original option list). For example, in the command
+ 'grep -r --exclude="a*" --include="*b" pat dir', the
+ first option is --exclude so any file name matching
+ neither a* nor *b is included. */
+ invert = true;
+ break;
+ }
+ }
+
+ free (filename);
+ return invert ^ ! (seg->options & EXCLUDE_INCLUDE);
+}
+
+/* Append to EX the exclusion PATTERN with OPTIONS. */
+
+void
+add_exclude (struct exclude *ex, char const *pattern, int options)
+{
+ struct exclude_segment *seg;
+ struct exclude_pattern *pat;
+ struct patopts *patopts;
+
+ if ((options & (EXCLUDE_REGEX|EXCLUDE_WILDCARDS))
+ && fnmatch_pattern_has_wildcards (pattern, options))
+ {
+ if (! (ex->head && ex->head->type == exclude_pattern
+ && ((ex->head->options & EXCLUDE_INCLUDE)
+ == (options & EXCLUDE_INCLUDE))))
+ new_exclude_segment (ex, exclude_pattern, options);
+
+ seg = ex->head;
+
+ pat = &seg->v.pat;
+ if (pat->exclude_count == pat->exclude_alloc)
+ pat->exclude = xpalloc (pat->exclude, &pat->exclude_alloc, 1, -1,
+ sizeof *pat->exclude);
+ patopts = &pat->exclude[pat->exclude_count++];
+
+ patopts->options = options;
+ if (options & EXCLUDE_REGEX)
+ {
+ int rc;
+ int cflags = REG_NOSUB|REG_EXTENDED|
+ ((options & FNM_CASEFOLD) ? REG_ICASE : 0);
+
+ if (options & FNM_LEADING_DIR)
+ {
+ char *tmp;
+ idx_t len = strlen (pattern);
+
+ while (len > 0 && ISSLASH (pattern[len-1]))
+ --len;
+
+ if (len == 0)
+ rc = 1;
+ else
+ {
+ tmp = ximalloc (len + 7);
+ memcpy (tmp, pattern, len);
+ strcpy (tmp + len, "(/.*)?");
+ rc = regcomp (&patopts->v.re, tmp, cflags);
+ free (tmp);
+ }
+ }
+ else
+ rc = regcomp (&patopts->v.re, pattern, cflags);
+
+ if (rc)
+ {
+ pat->exclude_count--;
+ return;
+ }
+ }
+ else
+ {
+ if (options & EXCLUDE_ALLOC)
+ {
+ pattern = xstrdup (pattern);
+ exclude_add_pattern_buffer (ex, (char*) pattern);
+ }
+ patopts->v.pattern = pattern;
+ }
+ }
+ else
+ {
+ char *str, *p;
+ int exclude_hash_flags = (EXCLUDE_INCLUDE | EXCLUDE_ANCHORED
+ | FNM_LEADING_DIR | FNM_CASEFOLD);
+ if (! (ex->head && ex->head->type == exclude_hash
+ && ((ex->head->options & exclude_hash_flags)
+ == (options & exclude_hash_flags))))
+ new_exclude_segment (ex, exclude_hash, options);
+ seg = ex->head;
+
+ str = xstrdup (pattern);
+ if ((options & (EXCLUDE_WILDCARDS | FNM_NOESCAPE)) == EXCLUDE_WILDCARDS)
+ unescape_pattern (str);
+ p = hash_insert (seg->v.table, str);
+ if (p != str)
+ free (str);
+ }
+}
+
+/* Use ADD_FUNC to append to EX the patterns in FILE_NAME, each with
+ OPTIONS. LINE_END terminates each pattern in the file. If
+ LINE_END is a space character, ignore trailing spaces and empty
+ lines in FP. Return -1 (setting errno) on failure, 0 on success. */
+
+int
+add_exclude_fp (void (*add_func) (struct exclude *, char const *, int, void *),
+ struct exclude *ex, FILE *fp, int options,
+ char line_end,
+ void *data)
+{
+ char *buf = NULL;
+ char *p;
+ char *pattern;
+ char const *lim;
+ idx_t buf_alloc = 0;
+ idx_t buf_count = 0;
+ int c;
+ int e = 0;
+
+ while ((c = getc (fp)) != EOF)
+ {
+ if (buf_count == buf_alloc)
+ buf = xpalloc (buf, &buf_alloc, 1, -1, 1);
+ buf[buf_count++] = c;
+ }
+
+ if (ferror (fp))
+ e = errno;
+
+ buf = xirealloc (buf, buf_count + 1);
+ buf[buf_count] = line_end;
+ lim = buf + buf_count + ! (buf_count == 0 || buf[buf_count - 1] == line_end);
+
+ exclude_add_pattern_buffer (ex, buf);
+
+ pattern = buf;
+
+ for (p = buf; p < lim; p++)
+ if (*p == line_end)
+ {
+ char *pattern_end = p;
+
+ if (isspace ((unsigned char) line_end))
+ {
+ for (; ; pattern_end--)
+ if (pattern_end == pattern)
+ goto next_pattern;
+ else if (! isspace ((unsigned char) pattern_end[-1]))
+ break;
+ }
+
+ *pattern_end = '\0';
+ (*add_func) (ex, pattern, options, data);
+
+ next_pattern:
+ pattern = p + 1;
+ }
+
+ errno = e;
+ return e ? -1 : 0;
+}
+
+static void
+call_addfn (struct exclude *ex, char const *pattern, int options, void *data)
+{
+ void (**addfnptr) (struct exclude *, char const *, int) = data;
+ (*addfnptr) (ex, pattern, options);
+}
+
+int
+add_exclude_file (void (*add_func) (struct exclude *, char const *, int),
+ struct exclude *ex, char const *file_name, int options,
+ char line_end)
+{
+ if (strcmp (file_name, "-") == 0)
+ return add_exclude_fp (call_addfn, ex, stdin, options, line_end, &add_func);
+
+ FILE *in = fopen (file_name, "re");
+ if (!in)
+ return -1;
+ int rc = add_exclude_fp (call_addfn, ex, in, options, line_end, &add_func);
+ int e = errno;
+ if (fclose (in) != 0)
+ return -1;
+ errno = e;
+ return rc;
+}