/* $Id: RTTimeZoneGetCurrent-posix.cpp $ */ /** @file * IPRT - RTTimeZoneGetCurrent, POSIX. */ /* * Copyright (C) 2020-2023 Oracle and/or its affiliates. * * This file is part of VirtualBox base platform packages, as * available from https://www.virtualbox.org. * * 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, in version 3 of the * License. * * 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 . * * The contents of this file may alternatively be used under the terms * of the Common Development and Distribution License Version 1.0 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included * in the VirtualBox distribution, in which case the provisions of the * CDDL are applicable instead of those of the GPL. * * You may elect to license modified versions of this file under the * terms and conditions of either the GPL or the CDDL or both. * * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 */ /********************************************************************************************************************************* * Header Files * *********************************************************************************************************************************/ #include #include "internal/iprt.h" #include #include #include #include #include #include #include #include #include #if defined(RT_OS_DARWIN) || defined(RT_OS_SOLARIS) # include #else # define TZDIR "/usr/share/zoneinfo" # define TZ_MAGIC "TZif" #endif /********************************************************************************************************************************* * Defined Constants And Macros * *********************************************************************************************************************************/ #define PATH_LOCALTIME "/etc/localtime" #if defined(RT_OS_FREEBSD) # define PATH_TIMEZONE "/var/db/zoneinfo" #else # define PATH_TIMEZONE "/etc/timezone" #endif #define PATH_SYSCONFIG_CLOCK "/etc/sysconfig/clock" /** * Checks if a time zone database file is valid by verifying it begins with * TZ_MAGIC. * * @returns IPRT status code. * @param pszTimezone The time zone database file relative to * :TZDIR (normally /usr/share/zoneinfo), * e.g. Europe/London, or Etc/UTC, or UTC, or etc. * * @note File format is documented in RFC-8536. */ static int rtIsValidTimeZoneFile(const char *pszTimeZone) { if (pszTimeZone == NULL || *pszTimeZone == '\0' || *pszTimeZone == '/') return VERR_INVALID_PARAMETER; int rc = RTStrValidateEncoding(pszTimeZone); if (RT_SUCCESS(rc)) { /* construct full pathname of the time zone file */ char szTZPath[RTPATH_MAX]; rc = RTPathJoin(szTZPath, sizeof(szTZPath), TZDIR, pszTimeZone); if (RT_SUCCESS(rc)) { /* open the time zone file and check that it begins with the correct magic number */ RTFILE hFile = NIL_RTFILE; rc = RTFileOpen(&hFile, szTZPath, RTFILE_O_READ | RTFILE_O_OPEN | RTFILE_O_DENY_WRITE); if (RT_SUCCESS(rc)) { char achTZBuf[sizeof(TZ_MAGIC)]; rc = RTFileRead(hFile, achTZBuf, sizeof(achTZBuf), NULL); RTFileClose(hFile); if (RT_SUCCESS(rc)) { if (memcmp(achTZBuf, RT_STR_TUPLE(TZ_MAGIC)) == 0) rc = VINF_SUCCESS; else rc = VERR_INVALID_MAGIC; } } } } return rc; } /** * Return the system time zone. * * @returns IPRT status code. * @param pszName The buffer to return the time zone in. * @param cbName The size of the pszName buffer. */ RTDECL(int) RTTimeZoneGetCurrent(char *pszName, size_t cbName) { int rc = RTEnvGetEx(RTENV_DEFAULT, "TZ", pszName, cbName, NULL); if (RT_SUCCESS(rc)) { /* * $TZ can have two different formats and one of them doesn't specify * a time zone database file under :TZDIR but since all * current callers of this routine expect a time zone filename we do * the validation check here so that if it is invalid then we fall back * to the other mechanisms to return the system's current time zone. */ if (*pszName == ':') /* POSIX allows $TZ to begin with a colon (:) so we allow for that here */ memmove(pszName, pszName + 1, strlen(pszName)); /** @todo this isn't perfect for absolute paths... Should probably try treat * it like /etc/localtime. */ rc = rtIsValidTimeZoneFile(pszName); if (RT_SUCCESS(rc)) return rc; } else if (rc != VERR_ENV_VAR_NOT_FOUND) return rc; /* * /etc/localtime is a symbolic link to the system time zone on many OSes * including Solaris, macOS, Ubuntu, RH/OEL 6 and later, Arch Linux, NetBSD, * and etc. We extract the time zone pathname relative to TZDIR defined in * which is normally /usr/share/zoneinfo. * * N.B. Some OSes have /etc/localtime as a regular file instead of a * symlink and while we could trawl through all the files under TZDIR * looking for a match we instead fallback to other popular mechanisms of * specifying the system-wide time zone for the sake of simplicity. */ char szBuf[RTPATH_MAX]; const char *pszPath = PATH_LOCALTIME; if (RTSymlinkExists(pszPath)) { /* the contents of the symink may contain '..' or other links */ char szLinkPathReal[RTPATH_MAX]; rc = RTPathReal(pszPath, szLinkPathReal, sizeof(szLinkPathReal)); if (RT_SUCCESS(rc)) { rc = RTPathReal(TZDIR, szBuf, sizeof(szBuf)); AssertRC(rc); if (RT_SUCCESS(rc)) { Assert(RTPathStartsWith(szLinkPathReal, szBuf)); if (RTPathStartsWith(szLinkPathReal, szBuf)) { /* :TZDIR doesn't include a trailing slash */ const char *pszTimeZone = &szLinkPathReal[strlen(szBuf) + 1]; rc = rtIsValidTimeZoneFile(pszTimeZone); if (RT_SUCCESS(rc)) return RTStrCopy(pszName, cbName, pszTimeZone); } } } } /* * /etc/timezone is a regular file consisting of a single line containing * the time zone (e.g. Europe/London or Etc/UTC or etc.) and is used by a * variety of Linux distros such as Ubuntu, Gentoo, Debian, and etc. * The equivalent on FreeBSD is /var/db/zoneinfo. */ pszPath = PATH_TIMEZONE; if (RTFileExists(pszPath)) { RTFILE hFile = NIL_RTFILE; rc = RTFileOpen(&hFile, PATH_TIMEZONE, RTFILE_O_READ | RTFILE_O_OPEN | RTFILE_O_DENY_WRITE); if (RT_SUCCESS(rc)) { size_t cbRead = 0; rc = RTFileRead(hFile, szBuf, sizeof(szBuf), &cbRead); RTFileClose(hFile); if (RT_SUCCESS(rc) && cbRead > 0) { /* Get the first line and strip it. */ szBuf[RT_MIN(sizeof(szBuf) - 1, cbRead)] = '\0'; size_t const offNewLine = RTStrOffCharOrTerm(szBuf, '\n'); szBuf[offNewLine] = '\0'; const char *pszTimeZone = RTStrStrip(szBuf); rc = rtIsValidTimeZoneFile(pszTimeZone); if (RT_SUCCESS(rc)) return RTStrCopy(pszName, cbName, pszTimeZone); } } } /* * Older versions of RedHat / OEL don't have /etc/localtime as a symlink or * /etc/timezone but instead have /etc/sysconfig/clock which contains a line * of the syntax ZONE=Europe/London or ZONE="Europe/London" amongst other entries. */ pszPath = PATH_SYSCONFIG_CLOCK; if (RTFileExists(pszPath)) { PRTSTREAM pStrm; rc = RTStrmOpen(pszPath, "r", &pStrm); if (RT_SUCCESS(rc)) { while (RT_SUCCESS(rc = RTStrmGetLine(pStrm, szBuf, sizeof(szBuf)))) { static char const s_szVarEq[] = "ZONE="; char *pszStart = RTStrStrip(szBuf); if (memcmp(pszStart, RT_STR_TUPLE(s_szVarEq)) == 0) { char *pszTimeZone = &pszStart[sizeof(s_szVarEq) - 1]; /* Drop any quoting before using the value, assuming it is plain stuff: */ if (*pszTimeZone == '\"' || *pszTimeZone == '\'') { pszTimeZone++; size_t const cchTimeZone = strlen(pszTimeZone); if (cchTimeZone && (pszTimeZone[cchTimeZone - 1] == '"' || pszTimeZone[cchTimeZone - 1] == '\'')) pszTimeZone[cchTimeZone - 1] = '\0'; } rc = rtIsValidTimeZoneFile(pszTimeZone); if (RT_SUCCESS(rc)) { RTStrmClose(pStrm); return RTStrCopy(pszName, cbName, pszTimeZone); } } } RTStrmClose(pStrm); } } return rc; }