/*-

 * Copyright (c) 2008 Joerg Sonnenberger

 * All rights reserved.

 *

 * 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.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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 AUTHOR(S) 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.

 */

#include "bsdtar_platform.h"

__FBSDID("$FreeBSD: src/usr.bin/tar/subst.c,v 1.4 2008/06/15 10:08:16 kientzle Exp $");

#if defined(HAVE_REGEX_H) || defined(HAVE_PCREPOSIX_H)

#include "bsdtar.h"

#include <errno.h>

#ifdef HAVE_PCREPOSIX_H

#include <pcreposix.h>

#else

#include <regex.h>

#endif

#include <stdlib.h>

#include <string.h>

#ifndef REG_BASIC

#define	REG_BASIC 0

#endif

#include "err.h"

struct subst_rule {

	struct subst_rule *next;

	regex_t re;

	char *result;

	unsigned int global:1, print:1, regular:1, symlink:1, hardlink:1;

};

struct substitution {

	struct subst_rule *first_rule, *last_rule;

};

static void

init_substitution(struct bsdtar *bsdtar)

{

	struct substitution *subst;

	bsdtar->substitution = subst = malloc(sizeof(*subst));

	if (subst == NULL)

		lafe_errc(1, errno, "Out of memory");

	subst->first_rule = subst->last_rule = NULL;

}

void

add_substitution(struct bsdtar *bsdtar, const char *rule_text)

{

	struct subst_rule *rule;

	struct substitution *subst;

	const char *end_pattern, *start_subst;

	char *pattern;

	int r;

	if ((subst = bsdtar->substitution) == NULL) {

		init_substitution(bsdtar);

		subst = bsdtar->substitution;

	}

	rule = malloc(sizeof(*rule));

	if (rule == NULL)

		lafe_errc(1, errno, "Out of memory");

	rule->next = NULL;

	rule->result = NULL;

	if (subst->last_rule == NULL)

		subst->first_rule = rule;

	else

		subst->last_rule->next = rule;

	subst->last_rule = rule;

	if (*rule_text == '\0')

		lafe_errc(1, 0, "Empty replacement string");

	end_pattern = strchr(rule_text + 1, *rule_text);

	if (end_pattern == NULL)

		lafe_errc(1, 0, "Invalid replacement string");

	pattern = malloc(end_pattern - rule_text);

	if (pattern == NULL)

		lafe_errc(1, errno, "Out of memory");

	memcpy(pattern, rule_text + 1, end_pattern - rule_text - 1);

	pattern[end_pattern - rule_text - 1] = '\0';

	if ((r = regcomp(&rule->re, pattern, REG_BASIC)) != 0) {

		char buf[80];

		regerror(r, &rule->re, buf, sizeof(buf));

		lafe_errc(1, 0, "Invalid regular expression: %s", buf);

	}

	free(pattern);

	start_subst = end_pattern + 1;

	end_pattern = strchr(start_subst, *rule_text);

	if (end_pattern == NULL)

		lafe_errc(1, 0, "Invalid replacement string");

	rule->result = malloc(end_pattern - start_subst + 1);

	if (rule->result == NULL)

		lafe_errc(1, errno, "Out of memory");

	memcpy(rule->result, start_subst, end_pattern - start_subst);

	rule->result[end_pattern - start_subst] = '\0';

	/* Defaults */

	rule->global = 0; /* Don't do multiple replacements. */

	rule->print = 0; /* Don't print. */

	rule->regular = 1; /* Rewrite regular filenames. */

	rule->symlink = 1; /* Rewrite symlink targets. */

	rule->hardlink = 1; /* Rewrite hardlink targets. */

	while (*++end_pattern) {

		switch (*end_pattern) {

		case 'g':

		case 'G':

			rule->global = 1;

			break;

		case 'h':

			rule->hardlink = 1;

			break;

		case 'H':

			rule->hardlink = 0;

			break;

		case 'p':

		case 'P':

			rule->print = 1;

			break;

		case 'r':

			rule->regular = 1;

			break;

		case 'R':

			rule->regular = 0;

			break;

		case 's':

			rule->symlink = 1;

			break;

		case 'S':

			rule->symlink = 0;

			break;

		default:

			lafe_errc(1, 0, "Invalid replacement flag %c", *end_pattern);

		}

	}

}

static void

realloc_strncat(char **str, const char *append, size_t len)

{

	char *new_str;

	size_t old_len;

	if (*str == NULL)

		old_len = 0;

	else

		old_len = strlen(*str);

	new_str = malloc(old_len + len + 1);

	if (new_str == NULL)

		lafe_errc(1, errno, "Out of memory");

	if (*str != NULL)

		memcpy(new_str, *str, old_len);

	memcpy(new_str + old_len, append, len);

	new_str[old_len + len] = '\0';

	free(*str);

	*str = new_str;

}

static void

realloc_strcat(char **str, const char *append)

{

	char *new_str;

	size_t old_len;

	if (*str == NULL)

		old_len = 0;

	else

		old_len = strlen(*str);

	new_str = malloc(old_len + strlen(append) + 1);

	if (new_str == NULL)

		lafe_errc(1, errno, "Out of memory");

	if (*str != NULL)

		memcpy(new_str, *str, old_len);

	strcpy(new_str + old_len, append);

	free(*str);

	*str = new_str;

}

int

apply_substitution(struct bsdtar *bsdtar, const char *name, char **result,

    int symlink_target, int hardlink_target)

{

	const char *path = name;

	regmatch_t matches[10];

	size_t i, j;

	struct subst_rule *rule;

	struct substitution *subst;

	int c, got_match, print_match;

	*result = NULL;

	if ((subst = bsdtar->substitution) == NULL)

		return 0;

	got_match = 0;

	print_match = 0;

	for (rule = subst->first_rule; rule != NULL; rule = rule->next) {

		if (symlink_target) {

			if (!rule->symlink)

				continue;

		} else if (hardlink_target) {

			if (!rule->hardlink)

				continue;

		} else { /* Regular filename. */

			if (!rule->regular)

				continue;

		}

		while (1) {

			if (regexec(&rule->re, name, 10, matches, 0))

				break;

			got_match = 1;

			print_match |= rule->print;

			realloc_strncat(result, name, matches[0].rm_so);

			for (i = 0, j = 0; rule->result[i] != '\0'; ++i) {

				if (rule->result[i] == '~') {

					realloc_strncat(result, rule->result + j, i - j);

					realloc_strncat(result,

					    name + matches[0].rm_so,

					    matches[0].rm_eo - matches[0].rm_so);

					j = i + 1;

					continue;

				}

				if (rule->result[i] != '\\')

					continue;

				++i;

				c = rule->result[i];

				switch (c) {

				case '~':

				case '\\':

					realloc_strncat(result, rule->result + j, i - j - 1);

					j = i;

					break;

				case '1':

				case '2':

				case '3':

				case '4':

				case '5':

				case '6':

				case '7':

				case '8':

				case '9':

					realloc_strncat(result, rule->result + j, i - j - 1);

					if ((size_t)(c - '0') > (size_t)(rule->re.re_nsub)) {

						free(*result);

						*result = NULL;

						return -1;

					}

					realloc_strncat(result, name + matches[c - '0'].rm_so, matches[c - '0'].rm_eo - matches[c - '0'].rm_so);

					j = i + 1;

					break;

				default:

					/* Just continue; */

					break;

				}

			}

			realloc_strcat(result, rule->result + j);

			name += matches[0].rm_eo;

			if (!rule->global)

				break;

		}

	}

	if (got_match)

		realloc_strcat(result, name);

	if (print_match)

		fprintf(stderr, "%s >> %s\n", path, *result);

	return got_match;

}

void

cleanup_substitution(struct bsdtar *bsdtar)

{

	struct subst_rule *rule;

	struct substitution *subst;

	if ((subst = bsdtar->substitution) == NULL)

		return;

	while ((rule = subst->first_rule) != NULL) {

		subst->first_rule = rule->next;

		free(rule->result);

		free(rule);

	}

	free(subst);

}

#endif /* defined(HAVE_REGEX_H) || defined(HAVE_PCREPOSIX_H) */