lib/posix/options/fnmatch.c

/* SPDX-License-Identifier: BSD-3-Clause */

/*    $NetBSD: fnmatch.c,v 1.26 2014/10/12 22:32:33 christos Exp $    */

/*
 * Copyright (c) 1989, 1993, 1994
 *    The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Guido van Rossum.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Function fnmatch() as specified in POSIX 1003.2-1992, section B.6.
 * Compares a filename or pathname to a pattern.
 */

#include <ctype.h>
#include <stdbool.h>
#include <string.h>

#include <zephyr/posix/fnmatch.h>
#include <zephyr/toolchain.h>

#define EOS '\0'

static inline int foldcase(int ch, int flags)
{

	if ((flags & FNM_CASEFOLD) != 0 && isupper(ch)) {
		return tolower(ch);
	}

	return ch;
}

#define FOLDCASE(ch, flags) foldcase((unsigned char)(ch), (flags))

static const char *rangematch(const char *pattern, int test, int flags)
{
	bool negate, ok, need;
	char c, c2;

	if (pattern == NULL) {
		return NULL;
	}

	/*
	 * A bracket expression starting with an unquoted circumflex
	 * character produces unspecified results (IEEE 1003.2-1992,
	 * 3.13.2).  This implementation treats it like '!', for
	 * consistency with the regular expression syntax.
	 * J.T. Conklin (conklin@ngai.kaleida.com)
	 */
	negate = *pattern == '!' || *pattern == '^';
	if (negate) {
		++pattern;
	}

	for (need = true, ok = false, c = FOLDCASE(*pattern++, flags); c != ']' || need;
	     c = FOLDCASE(*pattern++, flags)) {
		need = false;
		if (c == '/') {
			return (void *)-1;
		}

		if (c == '\\' && !(flags & FNM_NOESCAPE)) {
			c = FOLDCASE(*pattern++, flags);
		}

		if (c == EOS) {
			return NULL;
		}

		if (*pattern == '-') {
			c2 = FOLDCASE(*(pattern + 1), flags);
			if (c2 != EOS && c2 != ']') {
				pattern += 2;
				if (c2 == '\\' && !(flags & FNM_NOESCAPE)) {
					c2 = FOLDCASE(*pattern++, flags);
				}

				if (c2 == EOS) {
					return NULL;
				}

				if (c <= test && test <= c2) {
					ok = true;
				}
			}
		} else if (c == test) {
			ok = true;
		}
	}

	return ok == negate ? NULL : pattern;
}

static int fnmatchx(const char *pattern, const char *string, int flags, size_t recursion)
{
	const char *stringstart, *r;
	char c, test;

	if (pattern == NULL || string == NULL) {
		return FNM_NOMATCH;
	}

	if (recursion-- == 0) {
		return FNM_NORES;
	}

	for (stringstart = string;;) {
		c = FOLDCASE(*pattern++, flags);
		switch (c) {
		case EOS:
			if ((flags & FNM_LEADING_DIR) && *string == '/') {
				return 0;
			}

			return *string == EOS ? 0 : FNM_NOMATCH;
		case '?':
			if (*string == EOS) {
				return FNM_NOMATCH;
			}

			if (*string == '/' && (flags & FNM_PATHNAME)) {
				return FNM_NOMATCH;
			}

			if (*string == '.' && (flags & FNM_PERIOD) &&
			    (string == stringstart ||
			     ((flags & FNM_PATHNAME) && *(string - 1) == '/'))) {
				return FNM_NOMATCH;
			}

			++string;
			break;
		case '*':
			c = FOLDCASE(*pattern, flags);
			/* Collapse multiple stars. */
			while (c == '*') {
				c = FOLDCASE(*++pattern, flags);
			}

			if (*string == '.' && (flags & FNM_PERIOD) &&
			    (string == stringstart ||
			     ((flags & FNM_PATHNAME) && *(string - 1) == '/'))) {
				return FNM_NOMATCH;
			}

			/* Optimize for pattern with * at end or before /. */
			if (c == EOS) {
				if (flags & FNM_PATHNAME) {
					return (flags & FNM_LEADING_DIR) ||
							       strchr(string, '/') == NULL
						       ? 0
						       : FNM_NOMATCH;
				} else {
					return 0;
				}
			} else if (c == '/' && flags & FNM_PATHNAME) {
				string = strchr(string, '/');
				if (string == NULL) {
					return FNM_NOMATCH;
				}

				break;
			}

			/* General case, use recursion. */
			do {
				test = FOLDCASE(*string, flags);
				if (test == EOS) {
					break;
				}

				int e = fnmatchx(pattern, string, flags & ~FNM_PERIOD, recursion);

				if (e != FNM_NOMATCH) {
					return e;
				}

				if (test == '/' && flags & FNM_PATHNAME) {
					break;
				}

				++string;
			} while (true);

			return FNM_NOMATCH;
		case '[':
			if (*string == EOS) {
				return FNM_NOMATCH;
			}

			if (*string == '/' && flags & FNM_PATHNAME) {
				return FNM_NOMATCH;
			}

			r = rangematch(pattern, FOLDCASE(*string, flags), flags);
			if (r == NULL) {
				return FNM_NOMATCH;
			}

			if (r == (void *)-1) {
				if (*string != '[') {
					return FNM_NOMATCH;
				}
			} else {
				pattern = r;
			}

			++string;
			break;
		case '\\':
			if (!(flags & FNM_NOESCAPE)) {
				c = FOLDCASE(*pattern++, flags);
				if (c == EOS) {
					c = '\0';
					--pattern;
				}
			}
			__fallthrough;
		default:
			if (c != FOLDCASE(*string++, flags)) {
				return FNM_NOMATCH;
			}

			break;
		}
	}
}

int fnmatch(const char *pattern, const char *string, int flags)
{
	return fnmatchx(pattern, string, flags, 64);
}