src/java.base/unix/native/libjava/TimeZone_md.c
changeset 47216 71c04702a3d5
parent 40979 df846f0570fc
child 51105 c6600aba799b
child 56230 489867818774
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/unix/native/libjava/TimeZone_md.c	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,912 @@
+/*
+ * Copyright (c) 1999, 2016, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <strings.h>
+#include <time.h>
+#include <limits.h>
+#include <errno.h>
+#include <stddef.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <string.h>
+#include <dirent.h>
+#include <unistd.h>
+#if defined(__solaris__)
+#include <libscf.h>
+#endif
+
+#include "jvm.h"
+#include "TimeZone_md.h"
+
+#define SKIP_SPACE(p)   while (*p == ' ' || *p == '\t') p++;
+
+#define RESTARTABLE(_cmd, _result) do { \
+  do { \
+    _result = _cmd; \
+  } while((_result == -1) && (errno == EINTR)); \
+} while(0)
+
+#if defined(_ALLBSD_SOURCE)
+#define dirent64 dirent
+#define readdir64_r readdir_r
+#endif
+
+#if !defined(__solaris__) || defined(__sparcv9) || defined(amd64)
+#define fileopen        fopen
+#define filegets        fgets
+#define fileclose       fclose
+#endif
+
+#if defined(__linux__) || defined(_ALLBSD_SOURCE)
+static const char *ETC_TIMEZONE_FILE = "/etc/timezone";
+static const char *ZONEINFO_DIR = "/usr/share/zoneinfo";
+static const char *DEFAULT_ZONEINFO_FILE = "/etc/localtime";
+#else
+static const char *SYS_INIT_FILE = "/etc/default/init";
+static const char *ZONEINFO_DIR = "/usr/share/lib/zoneinfo";
+static const char *DEFAULT_ZONEINFO_FILE = "/usr/share/lib/zoneinfo/localtime";
+#endif /* defined(__linux__) || defined(_ALLBSD_SOURCE) */
+
+#if defined(_AIX)
+static const char *ETC_ENVIRONMENT_FILE = "/etc/environment";
+#endif
+
+#if defined(__linux__) || defined(MACOSX) || defined(__solaris__)
+
+/*
+ * Returns a pointer to the zone ID portion of the given zoneinfo file
+ * name, or NULL if the given string doesn't contain "zoneinfo/".
+ */
+static char *
+getZoneName(char *str)
+{
+    static const char *zidir = "zoneinfo/";
+
+    char *pos = strstr((const char *)str, zidir);
+    if (pos == NULL) {
+        return NULL;
+    }
+    return pos + strlen(zidir);
+}
+
+/*
+ * Returns a path name created from the given 'dir' and 'name' under
+ * UNIX. This function allocates memory for the pathname calling
+ * malloc(). NULL is returned if malloc() fails.
+ */
+static char *
+getPathName(const char *dir, const char *name) {
+    char *path;
+
+    path = (char *) malloc(strlen(dir) + strlen(name) + 2);
+    if (path == NULL) {
+        return NULL;
+    }
+    return strcat(strcat(strcpy(path, dir), "/"), name);
+}
+
+/*
+ * Scans the specified directory and its subdirectories to find a
+ * zoneinfo file which has the same content as /etc/localtime on Linux
+ * or /usr/share/lib/zoneinfo/localtime on Solaris given in 'buf'.
+ * If file is symbolic link, then the contents it points to are in buf.
+ * Returns a zone ID if found, otherwise, NULL is returned.
+ */
+static char *
+findZoneinfoFile(char *buf, size_t size, const char *dir)
+{
+    DIR *dirp = NULL;
+    struct stat statbuf;
+    struct dirent64 *dp = NULL;
+    struct dirent64 *entry = NULL;
+    char *pathname = NULL;
+    int fd = -1;
+    char *dbuf = NULL;
+    char *tz = NULL;
+    int res;
+    long name_max = 0;
+
+    dirp = opendir(dir);
+    if (dirp == NULL) {
+        return NULL;
+    }
+
+    name_max = pathconf(dir, _PC_NAME_MAX);
+    // If pathconf did not work, fall back to a mimimum buffer size.
+    if (name_max < 1024) {
+        name_max = 1024;
+    }
+
+    entry = (struct dirent64 *)malloc(offsetof(struct dirent64, d_name) + name_max + 1);
+    if (entry == NULL) {
+        (void) closedir(dirp);
+        return NULL;
+    }
+
+    while (readdir64_r(dirp, entry, &dp) == 0 && dp != NULL) {
+        /*
+         * Skip '.' and '..' (and possibly other .* files)
+         */
+        if (dp->d_name[0] == '.') {
+            continue;
+        }
+
+        /*
+         * Skip "ROC", "posixrules", and "localtime".
+         */
+        if ((strcmp(dp->d_name, "ROC") == 0)
+            || (strcmp(dp->d_name, "posixrules") == 0)
+#if defined(__solaris__)
+            /*
+             * Skip the "src" and "tab" directories on Solaris.
+             */
+            || (strcmp(dp->d_name, "src") == 0)
+            || (strcmp(dp->d_name, "tab") == 0)
+#endif
+            || (strcmp(dp->d_name, "localtime") == 0)) {
+            continue;
+        }
+
+        pathname = getPathName(dir, dp->d_name);
+        if (pathname == NULL) {
+            break;
+        }
+        RESTARTABLE(stat(pathname, &statbuf), res);
+        if (res == -1) {
+            break;
+        }
+
+        if (S_ISDIR(statbuf.st_mode)) {
+            tz = findZoneinfoFile(buf, size, pathname);
+            if (tz != NULL) {
+                break;
+            }
+        } else if (S_ISREG(statbuf.st_mode) && (size_t)statbuf.st_size == size) {
+            dbuf = (char *) malloc(size);
+            if (dbuf == NULL) {
+                break;
+            }
+            RESTARTABLE(open(pathname, O_RDONLY), fd);
+            if (fd == -1) {
+                break;
+            }
+            RESTARTABLE(read(fd, dbuf, size), res);
+            if (res != (ssize_t) size) {
+                break;
+            }
+            if (memcmp(buf, dbuf, size) == 0) {
+                tz = getZoneName(pathname);
+                if (tz != NULL) {
+                    tz = strdup(tz);
+                }
+                break;
+            }
+            free((void *) dbuf);
+            dbuf = NULL;
+            (void) close(fd);
+            fd = -1;
+        }
+        free((void *) pathname);
+        pathname = NULL;
+    }
+
+    if (entry != NULL) {
+        free((void *) entry);
+    }
+    if (dirp != NULL) {
+        (void) closedir(dirp);
+    }
+    if (pathname != NULL) {
+        free((void *) pathname);
+    }
+    if (fd != -1) {
+        (void) close(fd);
+    }
+    if (dbuf != NULL) {
+        free((void *) dbuf);
+    }
+    return tz;
+}
+
+#if defined(__linux__) || defined(MACOSX)
+
+/*
+ * Performs Linux specific mapping and returns a zone ID
+ * if found. Otherwise, NULL is returned.
+ */
+static char *
+getPlatformTimeZoneID()
+{
+    struct stat statbuf;
+    char *tz = NULL;
+    FILE *fp;
+    int fd;
+    char *buf;
+    size_t size;
+    int res;
+
+#if defined(__linux__)
+    /*
+     * Try reading the /etc/timezone file for Debian distros. There's
+     * no spec of the file format available. This parsing assumes that
+     * there's one line of an Olson tzid followed by a '\n', no
+     * leading or trailing spaces, no comments.
+     */
+    if ((fp = fopen(ETC_TIMEZONE_FILE, "r")) != NULL) {
+        char line[256];
+
+        if (fgets(line, sizeof(line), fp) != NULL) {
+            char *p = strchr(line, '\n');
+            if (p != NULL) {
+                *p = '\0';
+            }
+            if (strlen(line) > 0) {
+                tz = strdup(line);
+            }
+        }
+        (void) fclose(fp);
+        if (tz != NULL) {
+            return tz;
+        }
+    }
+#endif /* defined(__linux__) */
+
+    /*
+     * Next, try /etc/localtime to find the zone ID.
+     */
+    RESTARTABLE(lstat(DEFAULT_ZONEINFO_FILE, &statbuf), res);
+    if (res == -1) {
+        return NULL;
+    }
+
+    /*
+     * If it's a symlink, get the link name and its zone ID part. (The
+     * older versions of timeconfig created a symlink as described in
+     * the Red Hat man page. It was changed in 1999 to create a copy
+     * of a zoneinfo file. It's no longer possible to get the zone ID
+     * from /etc/localtime.)
+     */
+    if (S_ISLNK(statbuf.st_mode)) {
+        char linkbuf[PATH_MAX+1];
+        int len;
+
+        if ((len = readlink(DEFAULT_ZONEINFO_FILE, linkbuf, sizeof(linkbuf)-1)) == -1) {
+            jio_fprintf(stderr, (const char *) "can't get a symlink of %s\n",
+                        DEFAULT_ZONEINFO_FILE);
+            return NULL;
+        }
+        linkbuf[len] = '\0';
+        tz = getZoneName(linkbuf);
+        if (tz != NULL) {
+            tz = strdup(tz);
+            return tz;
+        }
+    }
+
+    /*
+     * If it's a regular file, we need to find out the same zoneinfo file
+     * that has been copied as /etc/localtime.
+     * If initial symbolic link resolution failed, we should treat target
+     * file as a regular file.
+     */
+    RESTARTABLE(open(DEFAULT_ZONEINFO_FILE, O_RDONLY), fd);
+    if (fd == -1) {
+        return NULL;
+    }
+
+    RESTARTABLE(fstat(fd, &statbuf), res);
+    if (res == -1) {
+        (void) close(fd);
+        return NULL;
+    }
+    size = (size_t) statbuf.st_size;
+    buf = (char *) malloc(size);
+    if (buf == NULL) {
+        (void) close(fd);
+        return NULL;
+    }
+
+    RESTARTABLE(read(fd, buf, size), res);
+    if (res != (ssize_t) size) {
+        (void) close(fd);
+        free((void *) buf);
+        return NULL;
+    }
+    (void) close(fd);
+
+    tz = findZoneinfoFile(buf, size, ZONEINFO_DIR);
+    free((void *) buf);
+    return tz;
+}
+
+#elif defined(__solaris__)
+
+#if !defined(__sparcv9) && !defined(amd64)
+
+/*
+ * Those file* functions mimic the UNIX stream io functions. This is
+ * because of the limitation of the number of open files on Solaris
+ * (32-bit mode only) due to the System V ABI.
+ */
+
+#define BUFFER_SIZE     4096
+
+static struct iobuffer {
+    int     magic;      /* -1 to distinguish from the real FILE */
+    int     fd;         /* file descriptor */
+    char    *buffer;    /* pointer to buffer */
+    char    *ptr;       /* current read pointer */
+    char    *endptr;    /* end pointer */
+};
+
+static int
+fileclose(FILE *stream)
+{
+    struct iobuffer *iop = (struct iobuffer *) stream;
+
+    if (iop->magic != -1) {
+        return fclose(stream);
+    }
+
+    if (iop == NULL) {
+        return 0;
+    }
+    close(iop->fd);
+    free((void *)iop->buffer);
+    free((void *)iop);
+    return 0;
+}
+
+static FILE *
+fileopen(const char *fname, const char *fmode)
+{
+    FILE *fp;
+    int fd;
+    struct iobuffer *iop;
+
+    if ((fp = fopen(fname, fmode)) != NULL) {
+        return fp;
+    }
+
+    /*
+     * It assumes read open.
+     */
+    RESTARTABLE(open(fname, O_RDONLY), fd);
+    if (fd == -1) {
+        return NULL;
+    }
+
+    /*
+     * Allocate struct iobuffer and its buffer
+     */
+    iop = malloc(sizeof(struct iobuffer));
+    if (iop == NULL) {
+        (void) close(fd);
+        errno = ENOMEM;
+        return NULL;
+    }
+    iop->magic = -1;
+    iop->fd = fd;
+    iop->buffer = malloc(BUFFER_SIZE);
+    if (iop->buffer == NULL) {
+        (void) close(fd);
+        free((void *) iop);
+        errno = ENOMEM;
+        return NULL;
+    }
+    iop->ptr = iop->buffer;
+    iop->endptr = iop->buffer;
+    return (FILE *)iop;
+}
+
+/*
+ * This implementation assumes that n is large enough and the line
+ * separator is '\n'.
+ */
+static char *
+filegets(char *s, int n, FILE *stream)
+{
+    struct iobuffer *iop = (struct iobuffer *) stream;
+    char *p;
+
+    if (iop->magic != -1) {
+        return fgets(s, n, stream);
+    }
+
+    p = s;
+    for (;;) {
+        char c;
+
+        if (iop->ptr == iop->endptr) {
+            ssize_t len;
+
+            RESTARTABLE(read(iop->fd, (void *)iop->buffer, BUFFER_SIZE), len);
+            if (len == -1) {
+                return NULL;
+            }
+            if (len == 0) {
+                *p = 0;
+                if (s == p) {
+                    return NULL;
+                }
+                return s;
+            }
+            iop->ptr = iop->buffer;
+            iop->endptr = iop->buffer + len;
+        }
+        c = *iop->ptr++;
+        *p++ = c;
+        if ((p - s) == (n - 1)) {
+            *p = 0;
+            return s;
+        }
+        if (c == '\n') {
+            *p = 0;
+            return s;
+        }
+    }
+    /*NOTREACHED*/
+}
+#endif /* !defined(__sparcv9) && !defined(amd64) */
+
+/*
+ * Performs Solaris dependent mapping. Returns a zone ID if
+ * found. Otherwise, NULL is returned.  Solaris libc looks up
+ * "/etc/default/init" to get the default TZ value if TZ is not defined
+ * as an environment variable.
+ */
+static char *
+getPlatformTimeZoneID()
+{
+    char *tz = NULL;
+    FILE *fp;
+
+    /*
+     * Try the TZ entry in /etc/default/init.
+     */
+    if ((fp = fileopen(SYS_INIT_FILE, "r")) != NULL) {
+        char line[256];
+        char quote = '\0';
+
+        while (filegets(line, sizeof(line), fp) != NULL) {
+            char *p = line;
+            char *s;
+            char c;
+
+            /* quick check for comment lines */
+            if (*p == '#') {
+                continue;
+            }
+            if (strncmp(p, "TZ=", 3) == 0) {
+                p += 3;
+                SKIP_SPACE(p);
+                c = *p;
+                if (c == '"' || c == '\'') {
+                    quote = c;
+                    p++;
+                }
+
+                /*
+                 * PSARC/2001/383: quoted string support
+                 */
+                for (s = p; (c = *s) != '\0' && c != '\n'; s++) {
+                    /* No '\\' is supported here. */
+                    if (c == quote) {
+                        quote = '\0';
+                        break;
+                    }
+                    if (c == ' ' && quote == '\0') {
+                        break;
+                    }
+                }
+                if (quote != '\0') {
+                    jio_fprintf(stderr, "ZoneInfo: unterminated time zone name in /etc/TIMEZONE\n");
+                }
+                *s = '\0';
+                tz = strdup(p);
+                break;
+            }
+        }
+        (void) fileclose(fp);
+    }
+    return tz;
+}
+
+#define TIMEZONE_FMRI   "svc:/system/timezone:default"
+#define TIMEZONE_PG     "timezone"
+#define LOCALTIME_PROP  "localtime"
+
+static void
+cleanupScf(scf_handle_t *h,
+           scf_snapshot_t *snap,
+           scf_instance_t *inst,
+           scf_propertygroup_t *pg,
+           scf_property_t *prop,
+           scf_value_t *val,
+           char *buf) {
+    if (buf != NULL) {
+        free(buf);
+    }
+    if (snap != NULL) {
+        scf_snapshot_destroy(snap);
+    }
+    if (val != NULL) {
+        scf_value_destroy(val);
+    }
+    if (prop != NULL) {
+        scf_property_destroy(prop);
+    }
+    if (pg != NULL) {
+        scf_pg_destroy(pg);
+    }
+    if (inst != NULL) {
+        scf_instance_destroy(inst);
+    }
+    if (h != NULL) {
+        scf_handle_destroy(h);
+    }
+}
+
+/*
+ * Returns a zone ID of Solaris when the TZ value is "localtime".
+ * First, it tries scf. If scf fails, it looks for the same file as
+ * /usr/share/lib/zoneinfo/localtime under /usr/share/lib/zoneinfo/.
+ */
+static char *
+getSolarisDefaultZoneID() {
+    char *tz = NULL;
+    struct stat statbuf;
+    size_t size;
+    char *buf;
+    int fd;
+    int res;
+    /* scf specific variables */
+    scf_handle_t *h = NULL;
+    scf_snapshot_t *snap = NULL;
+    scf_instance_t *inst = NULL;
+    scf_propertygroup_t *pg = NULL;
+    scf_property_t *prop = NULL;
+    scf_value_t *val = NULL;
+
+    if ((h = scf_handle_create(SCF_VERSION)) != NULL
+        && scf_handle_bind(h) == 0
+        && (inst = scf_instance_create(h)) != NULL
+        && (snap = scf_snapshot_create(h)) != NULL
+        && (pg = scf_pg_create(h)) != NULL
+        && (prop = scf_property_create(h)) != NULL
+        && (val = scf_value_create(h)) != NULL
+        && scf_handle_decode_fmri(h, TIMEZONE_FMRI, NULL, NULL, inst,
+                                  NULL, NULL, SCF_DECODE_FMRI_REQUIRE_INSTANCE) == 0
+        && scf_instance_get_snapshot(inst, "running", snap) == 0
+        && scf_instance_get_pg_composed(inst, snap, TIMEZONE_PG, pg) == 0
+        && scf_pg_get_property(pg, LOCALTIME_PROP, prop) == 0
+        && scf_property_get_value(prop, val) == 0) {
+        ssize_t len;
+
+        /* Gets the length of the zone ID string */
+        len = scf_value_get_astring(val, NULL, 0);
+        if (len != -1) {
+            tz = malloc(++len); /* +1 for a null byte */
+            if (tz != NULL && scf_value_get_astring(val, tz, len) != -1) {
+                cleanupScf(h, snap, inst, pg, prop, val, NULL);
+                return tz;
+            }
+        }
+    }
+    cleanupScf(h, snap, inst, pg, prop, val, tz);
+
+    RESTARTABLE(stat(DEFAULT_ZONEINFO_FILE, &statbuf), res);
+    if (res == -1) {
+        return NULL;
+    }
+    size = (size_t) statbuf.st_size;
+    buf = malloc(size);
+    if (buf == NULL) {
+        return NULL;
+    }
+    RESTARTABLE(open(DEFAULT_ZONEINFO_FILE, O_RDONLY), fd);
+    if (fd == -1) {
+        free((void *) buf);
+        return NULL;
+    }
+
+    RESTARTABLE(read(fd, buf, size), res);
+    if (res != (ssize_t) size) {
+        (void) close(fd);
+        free((void *) buf);
+        return NULL;
+    }
+    (void) close(fd);
+    tz = findZoneinfoFile(buf, size, ZONEINFO_DIR);
+    free((void *) buf);
+    return tz;
+}
+
+#endif /* defined(__solaris__) */
+
+#elif defined(_AIX)
+
+static char *
+getPlatformTimeZoneID()
+{
+    FILE *fp;
+    char *tz = NULL;
+    char *tz_key = "TZ=";
+    char line[256];
+    size_t tz_key_len = strlen(tz_key);
+
+    if ((fp = fopen(ETC_ENVIRONMENT_FILE, "r")) != NULL) {
+        while (fgets(line, sizeof(line), fp) != NULL) {
+            char *p = strchr(line, '\n');
+            if (p != NULL) {
+                *p = '\0';
+            }
+            if (0 == strncmp(line, tz_key, tz_key_len)) {
+                tz = strdup(line + tz_key_len);
+                break;
+            }
+        }
+        (void) fclose(fp);
+    }
+
+    return tz;
+}
+
+static char *
+mapPlatformToJavaTimezone(const char *java_home_dir, const char *tz) {
+    FILE *tzmapf;
+    char mapfilename[PATH_MAX + 1];
+    char line[256];
+    int linecount = 0;
+    char *tz_buf = NULL;
+    char *temp_tz = NULL;
+    char *javatz = NULL;
+    size_t tz_len = 0;
+
+    /* On AIX, the TZ environment variable may end with a comma
+     * followed by modifier fields. These are ignored here. */
+    temp_tz = strchr(tz, ',');
+    tz_len = (temp_tz == NULL) ? strlen(tz) : temp_tz - tz;
+    tz_buf = (char *)malloc(tz_len + 1);
+    memcpy(tz_buf, tz, tz_len);
+    tz_buf[tz_len] = 0;
+
+    /* Open tzmappings file, with buffer overrun check */
+    if ((strlen(java_home_dir) + 15) > PATH_MAX) {
+        jio_fprintf(stderr, "Path %s/lib/tzmappings exceeds maximum path length\n", java_home_dir);
+        goto tzerr;
+    }
+    strcpy(mapfilename, java_home_dir);
+    strcat(mapfilename, "/lib/tzmappings");
+    if ((tzmapf = fopen(mapfilename, "r")) == NULL) {
+        jio_fprintf(stderr, "can't open %s\n", mapfilename);
+        goto tzerr;
+    }
+
+    while (fgets(line, sizeof(line), tzmapf) != NULL) {
+        char *p = line;
+        char *sol = line;
+        char *java;
+        int result;
+
+        linecount++;
+        /*
+         * Skip comments and blank lines
+         */
+        if (*p == '#' || *p == '\n') {
+            continue;
+        }
+
+        /*
+         * Get the first field, platform zone ID
+         */
+        while (*p != '\0' && *p != '\t') {
+            p++;
+        }
+        if (*p == '\0') {
+            /* mapping table is broken! */
+            jio_fprintf(stderr, "tzmappings: Illegal format at near line %d.\n", linecount);
+            break;
+        }
+
+        *p++ = '\0';
+        if ((result = strncmp(tz_buf, sol, tz_len)) == 0) {
+            /*
+             * If this is the current platform zone ID,
+             * take the Java time zone ID (2nd field).
+             */
+            java = p;
+            while (*p != '\0' && *p != '\n') {
+                p++;
+            }
+
+            if (*p == '\0') {
+                /* mapping table is broken! */
+                jio_fprintf(stderr, "tzmappings: Illegal format at line %d.\n", linecount);
+                break;
+            }
+
+            *p = '\0';
+            javatz = strdup(java);
+            break;
+        } else if (result < 0) {
+            break;
+        }
+    }
+    (void) fclose(tzmapf);
+
+tzerr:
+    if (tz_buf != NULL ) {
+        free((void *) tz_buf);
+    }
+
+    if (javatz == NULL) {
+        return getGMTOffsetID();
+    }
+
+    return javatz;
+}
+
+#endif /* defined(_AIX) */
+
+/*
+ * findJavaTZ_md() maps platform time zone ID to Java time zone ID
+ * using <java_home>/lib/tzmappings. If the TZ value is not found, it
+ * trys some libc implementation dependent mappings. If it still
+ * can't map to a Java time zone ID, it falls back to the GMT+/-hh:mm
+ * form.
+ */
+/*ARGSUSED1*/
+char *
+findJavaTZ_md(const char *java_home_dir)
+{
+    char *tz;
+    char *javatz = NULL;
+    char *freetz = NULL;
+
+    tz = getenv("TZ");
+
+    if (tz == NULL || *tz == '\0') {
+        tz = getPlatformTimeZoneID();
+        freetz = tz;
+    }
+
+    if (tz != NULL) {
+        /* Ignore preceding ':' */
+        if (*tz == ':') {
+            tz++;
+        }
+#if defined(__linux__)
+        /* Ignore "posix/" prefix on Linux. */
+        if (strncmp(tz, "posix/", 6) == 0) {
+            tz += 6;
+        }
+#endif
+
+#if defined(_AIX)
+        /* On AIX do the platform to Java mapping. */
+        javatz = mapPlatformToJavaTimezone(java_home_dir, tz);
+        if (freetz != NULL) {
+            free((void *) freetz);
+        }
+#else
+#if defined(__solaris__)
+        /* Solaris might use localtime, so handle it here. */
+        if (strcmp(tz, "localtime") == 0) {
+            javatz = getSolarisDefaultZoneID();
+            if (freetz != NULL) {
+                free((void *) freetz);
+            }
+        } else
+#endif
+        if (freetz == NULL) {
+            /* strdup if we are still working on getenv result. */
+            javatz = strdup(tz);
+        } else if (freetz != tz) {
+            /* strdup and free the old buffer, if we moved the pointer. */
+            javatz = strdup(tz);
+            free((void *) freetz);
+        } else {
+            /* we are good if we already work on a freshly allocated buffer. */
+            javatz = tz;
+        }
+#endif
+    }
+
+    return javatz;
+}
+
+/**
+ * Returns a GMT-offset-based zone ID. (e.g., "GMT-08:00")
+ */
+
+#if defined(MACOSX)
+
+char *
+getGMTOffsetID()
+{
+    time_t offset;
+    char sign, buf[32];
+    struct tm local_tm;
+    time_t clock;
+
+    clock = time(NULL);
+    if (localtime_r(&clock, &local_tm) == NULL) {
+        return strdup("GMT");
+    }
+    offset = (time_t)local_tm.tm_gmtoff;
+    if (offset == 0) {
+        return strdup("GMT");
+    }
+    if (offset > 0) {
+        sign = '+';
+    } else {
+        offset = -offset;
+        sign = '-';
+    }
+    sprintf(buf, (const char *)"GMT%c%02d:%02d",
+            sign, (int)(offset/3600), (int)((offset%3600)/60));
+    return strdup(buf);
+}
+
+#else
+
+char *
+getGMTOffsetID()
+{
+    time_t offset;
+    char sign, buf[32];
+#if defined(__solaris__)
+    struct tm localtm;
+    time_t currenttime;
+
+    currenttime = time(NULL);
+    if (localtime_r(&currenttime, &localtm) == NULL) {
+        return strdup("GMT");
+    }
+
+    offset = localtm.tm_isdst ? altzone : timezone;
+#else
+    offset = timezone;
+#endif
+
+    if (offset == 0) {
+        return strdup("GMT");
+    }
+
+    /* Note that the time offset direction is opposite. */
+    if (offset > 0) {
+        sign = '-';
+    } else {
+        offset = -offset;
+        sign = '+';
+    }
+    sprintf(buf, (const char *)"GMT%c%02d:%02d",
+            sign, (int)(offset/3600), (int)((offset%3600)/60));
+    return strdup(buf);
+}
+#endif /* MACOSX */