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      1 /*	$NetBSD: dir.c,v 1.3 2025/01/26 16:25:36 christos Exp $	*/
      2 
      3 /*
      4  * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
      5  *
      6  * SPDX-License-Identifier: MPL-2.0
      7  *
      8  * This Source Code Form is subject to the terms of the Mozilla Public
      9  * License, v. 2.0. If a copy of the MPL was not distributed with this
     10  * file, you can obtain one at https://mozilla.org/MPL/2.0/.
     11  *
     12  * See the COPYRIGHT file distributed with this work for additional
     13  * information regarding copyright ownership.
     14  */
     15 
     16 /*! \file */
     17 
     18 #include <ctype.h>
     19 #include <errno.h>
     20 #include <netdb.h>
     21 #include <sys/stat.h>
     22 #include <sys/types.h>
     23 #include <unistd.h>
     24 
     25 #include <isc/dir.h>
     26 #include <isc/magic.h>
     27 #include <isc/string.h>
     28 #include <isc/util.h>
     29 
     30 #include "errno2result.h"
     31 
     32 #define ISC_DIR_MAGIC  ISC_MAGIC('D', 'I', 'R', '*')
     33 #define VALID_DIR(dir) ISC_MAGIC_VALID(dir, ISC_DIR_MAGIC)
     34 
     35 void
     36 isc_dir_init(isc_dir_t *dir) {
     37 	REQUIRE(dir != NULL);
     38 
     39 	dir->entry.name[0] = '\0';
     40 	dir->entry.length = 0;
     41 
     42 	dir->handle = NULL;
     43 
     44 	dir->magic = ISC_DIR_MAGIC;
     45 }
     46 
     47 /*!
     48  * \brief Allocate workspace and open directory stream. If either one fails,
     49  * NULL will be returned.
     50  */
     51 isc_result_t
     52 isc_dir_open(isc_dir_t *dir, const char *dirname) {
     53 	char *p;
     54 	isc_result_t result = ISC_R_SUCCESS;
     55 
     56 	REQUIRE(VALID_DIR(dir));
     57 	REQUIRE(dirname != NULL);
     58 
     59 	/*
     60 	 * Copy directory name.  Need to have enough space for the name,
     61 	 * a possible path separator, the wildcard, and the final NUL.
     62 	 */
     63 	if (strlen(dirname) + 3 > sizeof(dir->dirname)) {
     64 		/* XXXDCL ? */
     65 		return ISC_R_NOSPACE;
     66 	}
     67 	strlcpy(dir->dirname, dirname, sizeof(dir->dirname));
     68 
     69 	/*
     70 	 * Append path separator, if needed, and "*".
     71 	 */
     72 	p = dir->dirname + strlen(dir->dirname);
     73 	if (dir->dirname < p && *(p - 1) != '/') {
     74 		*p++ = '/';
     75 	}
     76 	*p++ = '*';
     77 	*p = '\0';
     78 
     79 	/*
     80 	 * Open stream.
     81 	 */
     82 	dir->handle = opendir(dirname);
     83 
     84 	if (dir->handle == NULL) {
     85 		return isc__errno2result(errno);
     86 	}
     87 
     88 	return result;
     89 }
     90 
     91 /*!
     92  * \brief Return previously retrieved file or get next one.
     93  *
     94  * Unix's dirent has
     95  * separate open and read functions, but the Win32 and DOS interfaces open
     96  * the dir stream and reads the first file in one operation.
     97  */
     98 isc_result_t
     99 isc_dir_read(isc_dir_t *dir) {
    100 	struct dirent *entry;
    101 
    102 	REQUIRE(VALID_DIR(dir) && dir->handle != NULL);
    103 
    104 	/*
    105 	 * Fetch next file in directory.
    106 	 */
    107 	entry = readdir(dir->handle);
    108 
    109 	if (entry == NULL) {
    110 		return ISC_R_NOMORE;
    111 	}
    112 
    113 	/*
    114 	 * Make sure that the space for the name is long enough.
    115 	 */
    116 	if (sizeof(dir->entry.name) <= strlen(entry->d_name)) {
    117 		return ISC_R_UNEXPECTED;
    118 	}
    119 
    120 	strlcpy(dir->entry.name, entry->d_name, sizeof(dir->entry.name));
    121 
    122 	/*
    123 	 * Some dirents have d_namlen, but it is not portable.
    124 	 */
    125 	dir->entry.length = strlen(entry->d_name);
    126 
    127 	return ISC_R_SUCCESS;
    128 }
    129 
    130 /*!
    131  * \brief Close directory stream.
    132  */
    133 void
    134 isc_dir_close(isc_dir_t *dir) {
    135 	REQUIRE(VALID_DIR(dir) && dir->handle != NULL);
    136 
    137 	(void)closedir(dir->handle);
    138 	dir->handle = NULL;
    139 }
    140 
    141 /*!
    142  * \brief Reposition directory stream at start.
    143  */
    144 isc_result_t
    145 isc_dir_reset(isc_dir_t *dir) {
    146 	REQUIRE(VALID_DIR(dir) && dir->handle != NULL);
    147 
    148 	rewinddir(dir->handle);
    149 
    150 	return ISC_R_SUCCESS;
    151 }
    152 
    153 isc_result_t
    154 isc_dir_chdir(const char *dirname) {
    155 	/*!
    156 	 * \brief Change the current directory to 'dirname'.
    157 	 */
    158 
    159 	REQUIRE(dirname != NULL);
    160 
    161 	if (chdir(dirname) < 0) {
    162 		return isc__errno2result(errno);
    163 	}
    164 
    165 	return ISC_R_SUCCESS;
    166 }
    167 
    168 isc_result_t
    169 isc_dir_chroot(const char *dirname) {
    170 #ifdef HAVE_CHROOT
    171 	void *tmp;
    172 #endif /* ifdef HAVE_CHROOT */
    173 
    174 	REQUIRE(dirname != NULL);
    175 
    176 #ifdef HAVE_CHROOT
    177 	/*
    178 	 * Try to use getservbyname and getprotobyname before chroot.
    179 	 * If WKS records are used in a zone under chroot, Name Service Switch
    180 	 * may fail to load library in chroot.
    181 	 * Do not report errors if it fails, we do not need any result now.
    182 	 */
    183 	tmp = getprotobyname("udp");
    184 	if (tmp != NULL) {
    185 		(void)getservbyname("domain", "udp");
    186 	}
    187 
    188 	if (chroot(dirname) < 0 || chdir("/") < 0) {
    189 		return isc__errno2result(errno);
    190 	}
    191 
    192 	return ISC_R_SUCCESS;
    193 #else  /* ifdef HAVE_CHROOT */
    194 	return ISC_R_NOTIMPLEMENTED;
    195 #endif /* ifdef HAVE_CHROOT */
    196 }
    197