/src/httpd/server/util_time.c

Source (jump to first uncovered line)
/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "util_time.h"
#include "apr_env.h"



/* Number of characters needed to format the microsecond part of a timestamp.
 * Microseconds have 6 digits plus one separator character makes 7.
 *   */
#define AP_CTIME_USEC_LENGTH      7

/* Length of ISO 8601 date/time (including trailing '\0') */
#define AP_CTIME_COMPACT_LEN      20

/* Length of timezone offset from GMT ([+-]hhmm) plus leading space */
#define AP_CTIME_GMTOFF_LEN       6

/* Cache for exploded values of recent timestamps
 */

struct exploded_time_cache_element {
    apr_int64_t t;
    apr_time_exp_t xt;
    apr_int64_t t_validate; /* please see comments in cached_explode() */
};

/* the "+ 1" is for the current second: */
#define TIME_CACHE_SIZE (AP_TIME_RECENT_THRESHOLD + 1)

/* Note that AP_TIME_RECENT_THRESHOLD is defined to
 * be a power of two minus one in util_time.h, so that
 * we can replace a modulo operation with a bitwise AND
 * when hashing items into a cache of size
 * AP_TIME_RECENT_THRESHOLD+1
 */
#define TIME_CACHE_MASK (AP_TIME_RECENT_THRESHOLD)

static struct exploded_time_cache_element exploded_cache_localtime[TIME_CACHE_SIZE];
static struct exploded_time_cache_element exploded_cache_gmt[TIME_CACHE_SIZE];


static apr_status_t cached_explode(apr_time_exp_t *xt, apr_time_t t,
                                   struct exploded_time_cache_element *cache,
                                   int use_gmt)
{
    apr_int64_t seconds = apr_time_sec(t);
    struct exploded_time_cache_element *cache_element =
        &(cache[seconds & TIME_CACHE_MASK]);
    struct exploded_time_cache_element cache_element_snapshot;

    /* The cache is implemented as a ring buffer.  Each second,
     * it uses a different element in the buffer.  The timestamp
     * in the element indicates whether the element contains the
     * exploded time for the current second (vs the time
     * 'now - AP_TIME_RECENT_THRESHOLD' seconds ago).  If the
     * cached value is for the current time, we use it.  Otherwise,
     * we compute the apr_time_exp_t and store it in this
     * cache element. Note that the timestamp in the cache
     * element is updated only after the exploded time.  Thus
     * if two threads hit this cache element simultaneously
     * at the start of a new second, they'll both explode the
     * time and store it.  I.e., the writers will collide, but
     * they'll be writing the same value.
     */
    if (cache_element->t >= seconds) {
        /* There is an intentional race condition in this design:
         * in a multithreaded app, one thread might be reading
         * from this cache_element to resolve a timestamp from
         * TIME_CACHE_SIZE seconds ago at the same time that
         * another thread is copying the exploded form of the
         * current time into the same cache_element.  (I.e., the
         * first thread might hit this element of the ring buffer
         * just as the element is being recycled.)  This can
         * also happen at the start of a new second, if a
         * reader accesses the cache_element after a writer
         * has updated cache_element.t but before the writer
         * has finished updating the whole cache_element.
         *
         * Rather than trying to prevent this race condition
         * with locks, we allow it to happen and then detect
         * and correct it.  The detection works like this:
         *   Step 1: Take a "snapshot" of the cache element by
         *           copying it into a temporary buffer.
         *   Step 2: Check whether the snapshot contains consistent
         *           data: the timestamps at the start and end of
         *           the cache_element should both match the 'seconds'
         *           value that we computed from the input time.
         *           If these three don't match, then the snapshot
         *           shows the cache_element in the middle of an
         *           update, and its contents are invalid.
         *   Step 3: If the snapshot is valid, use it.  Otherwise,
         *           just give up on the cache and explode the
         *           input time.
         */
        memcpy(&cache_element_snapshot, cache_element,
               sizeof(struct exploded_time_cache_element));
        if ((seconds != cache_element_snapshot.t) ||
            (seconds != cache_element_snapshot.t_validate)) {
            /* Invalid snapshot */
            if (use_gmt) {
                return apr_time_exp_gmt(xt, t);
            }
            else {
                return apr_time_exp_lt(xt, t);
            }
        }
        else {
            /* Valid snapshot */
            memcpy(xt, &(cache_element_snapshot.xt),
                   sizeof(apr_time_exp_t));
        }
    }
    else {
        apr_status_t r;
        if (use_gmt) {
            r = apr_time_exp_gmt(xt, t);
        }
        else {
            r = apr_time_exp_lt(xt, t);
        }
        if (r != APR_SUCCESS) {
            return r;
        }
        cache_element->t = seconds;
        memcpy(&(cache_element->xt), xt, sizeof(apr_time_exp_t));
        cache_element->t_validate = seconds;
    }
    xt->tm_usec = (int)apr_time_usec(t);
    return APR_SUCCESS;
}


AP_DECLARE(apr_status_t) ap_explode_recent_localtime(apr_time_exp_t * tm,
                                                     apr_time_t t)
{
    return cached_explode(tm, t, exploded_cache_localtime, 0);
}

AP_DECLARE(apr_status_t) ap_explode_recent_gmt(apr_time_exp_t * tm,
                                               apr_time_t t)
{
    return cached_explode(tm, t, exploded_cache_gmt, 1);
}

AP_DECLARE(apr_status_t) ap_recent_ctime(char *date_str, apr_time_t t)
{
    int len = APR_CTIME_LEN;
    return ap_recent_ctime_ex(date_str, t, AP_CTIME_OPTION_NONE, &len);
}

AP_DECLARE(apr_status_t) ap_recent_ctime_ex(char *date_str, apr_time_t t,
                                            int option, int *len)
{
    /* ### This code is a clone of apr_ctime(), except that it
     * uses ap_explode_recent_localtime() instead of apr_time_exp_lt().
     */
    apr_time_exp_t xt;
    const char *s;
    int real_year;
    int needed;


    /* Calculate the needed buffer length */
    if (option & AP_CTIME_OPTION_COMPACT)
        needed = AP_CTIME_COMPACT_LEN;
    else
        needed = APR_CTIME_LEN;

    if (option & AP_CTIME_OPTION_USEC) {
        needed += AP_CTIME_USEC_LENGTH;
    }

    if (option & AP_CTIME_OPTION_GMTOFF) {
        needed += AP_CTIME_GMTOFF_LEN;
    }

    /* Check the provided buffer length (note: above AP_CTIME_COMPACT_LEN
     * and APR_CTIME_LEN include the trailing '\0'; so does 'needed' then).
     */
    if (len && *len >= needed) {
        *len = needed;
    }
    else {
        if (len != NULL) {
            *len = 0;
        }
        return APR_ENOMEM;
    }

    /* example without options: "Wed Jun 30 21:49:08 1993" */
    /* example for compact format: "1993-06-30 21:49:08" */
    /* example for compact+usec+gmtoff format:
     *     "1993-06-30 22:49:08.123456 +0100"
     */

    ap_explode_recent_localtime(&xt, t);
    real_year = 1900 + xt.tm_year;
    if (option & AP_CTIME_OPTION_COMPACT) {
        int real_month = xt.tm_mon + 1;
        *date_str++ = real_year / 1000 + '0';
        *date_str++ = real_year % 1000 / 100 + '0';
        *date_str++ = real_year % 100 / 10 + '0';
        *date_str++ = real_year % 10 + '0';
        *date_str++ = '-';
        *date_str++ = real_month / 10 + '0';
        *date_str++ = real_month % 10 + '0';
        *date_str++ = '-';
    }
    else {
        s = &apr_day_snames[xt.tm_wday][0];
        *date_str++ = *s++;
        *date_str++ = *s++;
        *date_str++ = *s++;
        *date_str++ = ' ';
        s = &apr_month_snames[xt.tm_mon][0];
        *date_str++ = *s++;
        *date_str++ = *s++;
        *date_str++ = *s++;
        *date_str++ = ' ';
    }
    *date_str++ = xt.tm_mday / 10 + '0';
    *date_str++ = xt.tm_mday % 10 + '0';
    *date_str++ = ' ';
    *date_str++ = xt.tm_hour / 10 + '0';
    *date_str++ = xt.tm_hour % 10 + '0';
    *date_str++ = ':';
    *date_str++ = xt.tm_min / 10 + '0';
    *date_str++ = xt.tm_min % 10 + '0';
    *date_str++ = ':';
    *date_str++ = xt.tm_sec / 10 + '0';
    *date_str++ = xt.tm_sec % 10 + '0';
    if (option & AP_CTIME_OPTION_USEC) {
        int div;
        int usec = (int)xt.tm_usec;
        *date_str++ = '.';
        for (div=100000; div>0; div=div/10) {
            *date_str++ = usec / div + '0';
            usec = usec % div;
        }
    }
    if (!(option & AP_CTIME_OPTION_COMPACT)) {
        *date_str++ = ' ';
        *date_str++ = real_year / 1000 + '0';
        *date_str++ = real_year % 1000 / 100 + '0';
        *date_str++ = real_year % 100 / 10 + '0';
        *date_str++ = real_year % 10 + '0';
    }
    if (option & AP_CTIME_OPTION_GMTOFF) {
        int off = xt.tm_gmtoff, off_hh, off_mm;
        char sign = '+';
        if (off < 0) {
            off = -off;
            sign = '-';
        }
        off_hh = off / 3600;
        off_mm = off % 3600 / 60;
        *date_str++ = ' ';
        *date_str++ = sign;
        *date_str++ = off_hh / 10 + '0';
        *date_str++ = off_hh % 10 + '0';
        *date_str++ = off_mm / 10 + '0';
        *date_str++ = off_mm % 10 + '0';
    }
    *date_str = 0;

    return APR_SUCCESS;
}

AP_DECLARE(apr_status_t) ap_recent_rfc822_date(char *date_str, apr_time_t t)
{
    /* ### This code is a clone of apr_rfc822_date(), except that it
     * uses ap_explode_recent_gmt() instead of apr_time_exp_gmt().
     */
    apr_time_exp_t xt;
    const char *s;
    int real_year;

    ap_explode_recent_gmt(&xt, t);

    /* example: "Sat, 08 Jan 2000 18:31:41 GMT" */
    /*           12345678901234567890123456789  */

    s = &apr_day_snames[xt.tm_wday][0];
    *date_str++ = *s++;
    *date_str++ = *s++;
    *date_str++ = *s++;
    *date_str++ = ',';
    *date_str++ = ' ';
    *date_str++ = xt.tm_mday / 10 + '0';
    *date_str++ = xt.tm_mday % 10 + '0';
    *date_str++ = ' ';
    s = &apr_month_snames[xt.tm_mon][0];
    *date_str++ = *s++;
    *date_str++ = *s++;
    *date_str++ = *s++;
    *date_str++ = ' ';
    real_year = 1900 + xt.tm_year;
    /* This routine isn't y10k ready. */
    *date_str++ = real_year / 1000 + '0';
    *date_str++ = real_year % 1000 / 100 + '0';
    *date_str++ = real_year % 100 / 10 + '0';
    *date_str++ = real_year % 10 + '0';
    *date_str++ = ' ';
    *date_str++ = xt.tm_hour / 10 + '0';
    *date_str++ = xt.tm_hour % 10 + '0';
    *date_str++ = ':';
    *date_str++ = xt.tm_min / 10 + '0';
    *date_str++ = xt.tm_min % 10 + '0';
    *date_str++ = ':';
    *date_str++ = xt.tm_sec / 10 + '0';
    *date_str++ = xt.tm_sec % 10 + '0';
    *date_str++ = ' ';
    *date_str++ = 'G';
    *date_str++ = 'M';
    *date_str++ = 'T';
    *date_str++ = 0;
    return APR_SUCCESS;
}

AP_DECLARE(void) ap_force_set_tz(apr_pool_t *p) {
    /* If the TZ variable is unset, many operating systems,
     * such as Linux, will at runtime read from /etc/localtime
     * and call fstat on it.
     *
     * By forcing the time zone to UTC if it is unset, we gain
     * about 2% in raw requests/second (since we format log files
     * in the local time, if present)
     *
     * For more info, see:
     *   <http://www.gnu.org/s/hello/manual/libc/TZ-Variable.html>
     */
    char *v = NULL;

    if (apr_env_get(&v, "TZ", p) != APR_SUCCESS) {
        apr_env_set("TZ", "UTC+0", p);
    }
}

Coverage Report

Created: 2023-03-26 06:28

Line	Count	Source (jump to first uncovered line)
1		/* Licensed to the Apache Software Foundation (ASF) under one or more
2		* contributor license agreements. See the NOTICE file distributed with
3		* this work for additional information regarding copyright ownership.
4		* The ASF licenses this file to You under the Apache License, Version 2.0
5		* (the "License"); you may not use this file except in compliance with
6		* the License. You may obtain a copy of the License at
7		*
8		* http://www.apache.org/licenses/LICENSE-2.0
9		*
10		* Unless required by applicable law or agreed to in writing, software
11		* distributed under the License is distributed on an "AS IS" BASIS,
12		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13		* See the License for the specific language governing permissions and
14		* limitations under the License.
15		*/
16
17		#include "util_time.h"
18		#include "apr_env.h"
19
20
21
22		/* Number of characters needed to format the microsecond part of a timestamp.
23		* Microseconds have 6 digits plus one separator character makes 7.
24		* */
25	0	#define AP_CTIME_USEC_LENGTH 7
26
27		/* Length of ISO 8601 date/time (including trailing '\0') */
28	0	#define AP_CTIME_COMPACT_LEN 20
29
30		/* Length of timezone offset from GMT ([+-]hhmm) plus leading space */
31	0	#define AP_CTIME_GMTOFF_LEN 6
32
33		/* Cache for exploded values of recent timestamps
34		*/
35
36		struct exploded_time_cache_element {
37		apr_int64_t t;
38		apr_time_exp_t xt;
39		apr_int64_t t_validate; /* please see comments in cached_explode() */
40		};
41
42		/* the "+ 1" is for the current second: */
43		#define TIME_CACHE_SIZE (AP_TIME_RECENT_THRESHOLD + 1)
44
45		/* Note that AP_TIME_RECENT_THRESHOLD is defined to
46		* be a power of two minus one in util_time.h, so that
47		* we can replace a modulo operation with a bitwise AND
48		* when hashing items into a cache of size
49		* AP_TIME_RECENT_THRESHOLD+1
50		*/
51	0	#define TIME_CACHE_MASK (AP_TIME_RECENT_THRESHOLD)
52
53		static struct exploded_time_cache_element exploded_cache_localtime[TIME_CACHE_SIZE];
54		static struct exploded_time_cache_element exploded_cache_gmt[TIME_CACHE_SIZE];
55
56
57		static apr_status_t cached_explode(apr_time_exp_t *xt, apr_time_t t,
58		struct exploded_time_cache_element *cache,
59		int use_gmt)
60	0	{
61	0	apr_int64_t seconds = apr_time_sec(t);
62	0	struct exploded_time_cache_element *cache_element =
63	0	&(cache[seconds & TIME_CACHE_MASK]);
64	0	struct exploded_time_cache_element cache_element_snapshot;
65
66		/* The cache is implemented as a ring buffer. Each second,
67		* it uses a different element in the buffer. The timestamp
68		* in the element indicates whether the element contains the
69		* exploded time for the current second (vs the time
70		* 'now - AP_TIME_RECENT_THRESHOLD' seconds ago). If the
71		* cached value is for the current time, we use it. Otherwise,
72		* we compute the apr_time_exp_t and store it in this
73		* cache element. Note that the timestamp in the cache
74		* element is updated only after the exploded time. Thus
75		* if two threads hit this cache element simultaneously
76		* at the start of a new second, they'll both explode the
77		* time and store it. I.e., the writers will collide, but
78		* they'll be writing the same value.
79		*/
80	0	if (cache_element->t >= seconds) {
81		/* There is an intentional race condition in this design:
82		* in a multithreaded app, one thread might be reading
83		* from this cache_element to resolve a timestamp from
84		* TIME_CACHE_SIZE seconds ago at the same time that
85		* another thread is copying the exploded form of the
86		* current time into the same cache_element. (I.e., the
87		* first thread might hit this element of the ring buffer
88		* just as the element is being recycled.) This can
89		* also happen at the start of a new second, if a
90		* reader accesses the cache_element after a writer
91		* has updated cache_element.t but before the writer
92		* has finished updating the whole cache_element.
93		*
94		* Rather than trying to prevent this race condition
95		* with locks, we allow it to happen and then detect
96		* and correct it. The detection works like this:
97		* Step 1: Take a "snapshot" of the cache element by
98		* copying it into a temporary buffer.
99		* Step 2: Check whether the snapshot contains consistent
100		* data: the timestamps at the start and end of
101		* the cache_element should both match the 'seconds'
102		* value that we computed from the input time.
103		* If these three don't match, then the snapshot
104		* shows the cache_element in the middle of an
105		* update, and its contents are invalid.
106		* Step 3: If the snapshot is valid, use it. Otherwise,
107		* just give up on the cache and explode the
108		* input time.
109		*/
110	0	memcpy(&cache_element_snapshot, cache_element,
111	0	sizeof(struct exploded_time_cache_element));
112	0	if ((seconds != cache_element_snapshot.t) \|\|
113	0	(seconds != cache_element_snapshot.t_validate)) {
114		/* Invalid snapshot */
115	0	if (use_gmt) {
116	0	return apr_time_exp_gmt(xt, t);
117	0	}
118	0	else {
119	0	return apr_time_exp_lt(xt, t);
120	0	}
121	0	}
122	0	else {
123		/* Valid snapshot */
124	0	memcpy(xt, &(cache_element_snapshot.xt),
125	0	sizeof(apr_time_exp_t));
126	0	}
127	0	}
128	0	else {
129	0	apr_status_t r;
130	0	if (use_gmt) {
131	0	r = apr_time_exp_gmt(xt, t);
132	0	}
133	0	else {
134	0	r = apr_time_exp_lt(xt, t);
135	0	}
136	0	if (r != APR_SUCCESS) {
137	0	return r;
138	0	}
139	0	cache_element->t = seconds;
140	0	memcpy(&(cache_element->xt), xt, sizeof(apr_time_exp_t));
141	0	cache_element->t_validate = seconds;
142	0	}
143	0	xt->tm_usec = (int)apr_time_usec(t);
144	0	return APR_SUCCESS;
145	0	}
146
147
148		AP_DECLARE(apr_status_t) ap_explode_recent_localtime(apr_time_exp_t * tm,
149		apr_time_t t)
150	0	{
151	0	return cached_explode(tm, t, exploded_cache_localtime, 0);
152	0	}
153
154		AP_DECLARE(apr_status_t) ap_explode_recent_gmt(apr_time_exp_t * tm,
155		apr_time_t t)
156	0	{
157	0	return cached_explode(tm, t, exploded_cache_gmt, 1);
158	0	}
159
160		AP_DECLARE(apr_status_t) ap_recent_ctime(char *date_str, apr_time_t t)
161	0	{
162	0	int len = APR_CTIME_LEN;
163	0	return ap_recent_ctime_ex(date_str, t, AP_CTIME_OPTION_NONE, &len);
164	0	}
165
166		AP_DECLARE(apr_status_t) ap_recent_ctime_ex(char *date_str, apr_time_t t,
167		int option, int *len)
168	0	{
169		/* ### This code is a clone of apr_ctime(), except that it
170		* uses ap_explode_recent_localtime() instead of apr_time_exp_lt().
171		*/
172	0	apr_time_exp_t xt;
173	0	const char *s;
174	0	int real_year;
175	0	int needed;
176
177
178		/* Calculate the needed buffer length */
179	0	if (option & AP_CTIME_OPTION_COMPACT)
180	0	needed = AP_CTIME_COMPACT_LEN;
181	0	else
182	0	needed = APR_CTIME_LEN;
183
184	0	if (option & AP_CTIME_OPTION_USEC) {
185	0	needed += AP_CTIME_USEC_LENGTH;
186	0	}
187
188	0	if (option & AP_CTIME_OPTION_GMTOFF) {
189	0	needed += AP_CTIME_GMTOFF_LEN;
190	0	}
191
192		/* Check the provided buffer length (note: above AP_CTIME_COMPACT_LEN
193		* and APR_CTIME_LEN include the trailing '\0'; so does 'needed' then).
194		*/
195	0	if (len && *len >= needed) {
196	0	*len = needed;
197	0	}
198	0	else {
199	0	if (len != NULL) {
200	0	*len = 0;
201	0	}
202	0	return APR_ENOMEM;
203	0	}
204
205		/* example without options: "Wed Jun 30 21:49:08 1993" */
206		/* example for compact format: "1993-06-30 21:49:08" */
207		/* example for compact+usec+gmtoff format:
208		* "1993-06-30 22:49:08.123456 +0100"
209		*/
210
211	0	ap_explode_recent_localtime(&xt, t);
212	0	real_year = 1900 + xt.tm_year;
213	0	if (option & AP_CTIME_OPTION_COMPACT) {
214	0	int real_month = xt.tm_mon + 1;
215	0	*date_str++ = real_year / 1000 + '0';
216	0	*date_str++ = real_year % 1000 / 100 + '0';
217	0	*date_str++ = real_year % 100 / 10 + '0';
218	0	*date_str++ = real_year % 10 + '0';
219	0	*date_str++ = '-';
220	0	*date_str++ = real_month / 10 + '0';
221	0	*date_str++ = real_month % 10 + '0';
222	0	*date_str++ = '-';
223	0	}
224	0	else {
225	0	s = &apr_day_snames[xt.tm_wday][0];
226	0	date_str++ = s++;
227	0	date_str++ = s++;
228	0	date_str++ = s++;
229	0	*date_str++ = ' ';
230	0	s = &apr_month_snames[xt.tm_mon][0];
231	0	date_str++ = s++;
232	0	date_str++ = s++;
233	0	date_str++ = s++;
234	0	*date_str++ = ' ';
235	0	}
236	0	*date_str++ = xt.tm_mday / 10 + '0';
237	0	*date_str++ = xt.tm_mday % 10 + '0';
238	0	*date_str++ = ' ';
239	0	*date_str++ = xt.tm_hour / 10 + '0';
240	0	*date_str++ = xt.tm_hour % 10 + '0';
241	0	*date_str++ = ':';
242	0	*date_str++ = xt.tm_min / 10 + '0';
243	0	*date_str++ = xt.tm_min % 10 + '0';
244	0	*date_str++ = ':';
245	0	*date_str++ = xt.tm_sec / 10 + '0';
246	0	*date_str++ = xt.tm_sec % 10 + '0';
247	0	if (option & AP_CTIME_OPTION_USEC) {
248	0	int div;
249	0	int usec = (int)xt.tm_usec;
250	0	*date_str++ = '.';
251	0	for (div=100000; div>0; div=div/10) {
252	0	*date_str++ = usec / div + '0';
253	0	usec = usec % div;
254	0	}
255	0	}
256	0	if (!(option & AP_CTIME_OPTION_COMPACT)) {
257	0	*date_str++ = ' ';
258	0	*date_str++ = real_year / 1000 + '0';
259	0	*date_str++ = real_year % 1000 / 100 + '0';
260	0	*date_str++ = real_year % 100 / 10 + '0';
261	0	*date_str++ = real_year % 10 + '0';
262	0	}
263	0	if (option & AP_CTIME_OPTION_GMTOFF) {
264	0	int off = xt.tm_gmtoff, off_hh, off_mm;
265	0	char sign = '+';
266	0	if (off < 0) {
267	0	off = -off;
268	0	sign = '-';
269	0	}
270	0	off_hh = off / 3600;
271	0	off_mm = off % 3600 / 60;
272	0	*date_str++ = ' ';
273	0	*date_str++ = sign;
274	0	*date_str++ = off_hh / 10 + '0';
275	0	*date_str++ = off_hh % 10 + '0';
276	0	*date_str++ = off_mm / 10 + '0';
277	0	*date_str++ = off_mm % 10 + '0';
278	0	}
279	0	*date_str = 0;
280
281	0	return APR_SUCCESS;
282	0	}
283
284		AP_DECLARE(apr_status_t) ap_recent_rfc822_date(char *date_str, apr_time_t t)
285	0	{
286		/* ### This code is a clone of apr_rfc822_date(), except that it
287		* uses ap_explode_recent_gmt() instead of apr_time_exp_gmt().
288		*/
289	0	apr_time_exp_t xt;
290	0	const char *s;
291	0	int real_year;
292
293	0	ap_explode_recent_gmt(&xt, t);
294
295		/* example: "Sat, 08 Jan 2000 18:31:41 GMT" */
296		/* 12345678901234567890123456789 */
297
298	0	s = &apr_day_snames[xt.tm_wday][0];
299	0	date_str++ = s++;
300	0	date_str++ = s++;
301	0	date_str++ = s++;
302	0	*date_str++ = ',';
303	0	*date_str++ = ' ';
304	0	*date_str++ = xt.tm_mday / 10 + '0';
305	0	*date_str++ = xt.tm_mday % 10 + '0';
306	0	*date_str++ = ' ';
307	0	s = &apr_month_snames[xt.tm_mon][0];
308	0	date_str++ = s++;
309	0	date_str++ = s++;
310	0	date_str++ = s++;
311	0	*date_str++ = ' ';
312	0	real_year = 1900 + xt.tm_year;
313		/* This routine isn't y10k ready. */
314	0	*date_str++ = real_year / 1000 + '0';
315	0	*date_str++ = real_year % 1000 / 100 + '0';
316	0	*date_str++ = real_year % 100 / 10 + '0';
317	0	*date_str++ = real_year % 10 + '0';
318	0	*date_str++ = ' ';
319	0	*date_str++ = xt.tm_hour / 10 + '0';
320	0	*date_str++ = xt.tm_hour % 10 + '0';
321	0	*date_str++ = ':';
322	0	*date_str++ = xt.tm_min / 10 + '0';
323	0	*date_str++ = xt.tm_min % 10 + '0';
324	0	*date_str++ = ':';
325	0	*date_str++ = xt.tm_sec / 10 + '0';
326	0	*date_str++ = xt.tm_sec % 10 + '0';
327	0	*date_str++ = ' ';
328	0	*date_str++ = 'G';
329	0	*date_str++ = 'M';
330	0	*date_str++ = 'T';
331	0	*date_str++ = 0;
332	0	return APR_SUCCESS;
333	0	}
334
335	0	AP_DECLARE(void) ap_force_set_tz(apr_pool_t *p) {
336		/* If the TZ variable is unset, many operating systems,
337		* such as Linux, will at runtime read from /etc/localtime
338		* and call fstat on it.
339		*
340		* By forcing the time zone to UTC if it is unset, we gain
341		* about 2% in raw requests/second (since we format log files
342		* in the local time, if present)
343		*
344		* For more info, see:
345		* <http://www.gnu.org/s/hello/manual/libc/TZ-Variable.html>
346		*/
347	0	char *v = NULL;
348
349	0	if (apr_env_get(&v, "TZ", p) != APR_SUCCESS) {
350	0	apr_env_set("TZ", "UTC+0", p);
351	0	}
352	0	}