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Add internal APIs for dealing with time

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The logging APIs need to be able to generate formatted timestamps
using only async signal safe functions. This rules out using
gmtime/localtime/malloc/gettimeday(!) and much more.

Introduce a new internal API which is async signal safe.

  virTimeMillisNowRaw replacement for gettimeofday. Uses clock_gettime
                      where available, otherwise falls back to the unsafe
                      gettimeofday

  virTimeFieldsNowRaw  replacements for gmtime(), convert a timestamp
  virTimeFieldsThenRaw into a broken out set of fields. No localtime()
                       replacement is provided, because converting to
                       local time is not practical with only async signal
                       safe APIs.

  virTimeStringNowRaw  replacements for strftime() which print a timestamp
  virTimeStringThenRaw into a string, using a pre-determined format, with
                       a fixed size buffer (VIR_TIME_STRING_BUFLEN)

For each of these there is also a version without the Raw postfix
which raises a full libvirt error. These versions are not async
signal safe

* src/Makefile.am, src/util/virtime.c, src/util/virtime.h: New files
* src/libvirt_private.syms: New APis
* configure.ac: Check for clock_gettime in -lrt
* tests/virtimetest.c, tests/Makefile.am: Test new APIs
This commit is contained in:
Daniel P. Berrange 2011-11-29 12:11:01 +00:00
parent 380110cf08
commit 3ec1289896
9 changed files with 577 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
configure.ac
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@ -147,6 +147,16 @@ LIBS="$LIBS $LIB_PTHREAD $LIBMULTITHREAD"
AC_CHECK_FUNCS([pthread_mutexattr_init])
LIBS=$old_libs
old_LIBS=$LIBS
RT_LIBS=
LIBS="$LIBS $LIB_PTHREAD -lrt"
AC_CHECK_FUNC([clock_gettime],[
AC_DEFINE([HAVE_CLOCK_GETTIME],[],[Defined if clock_gettime() exists in librt.so])
RT_LIBS=-lrt
])
LIBS=$old_libs
AC_SUBST(RT_LIBS)
dnl Availability of various common headers (non-fatal if missing).
AC_CHECK_HEADERS([pwd.h paths.h regex.h sys/un.h \
sys/poll.h syslog.h mntent.h net/ethernet.h linux/magic.h \

1
po/POTFILES.in
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@ -134,6 +134,7 @@ src/util/virnodesuspend.c
src/util/virpidfile.c
src/util/virsocketaddr.c
src/util/virterror.c
src/util/virtime.c
src/util/xml.c
src/vbox/vbox_MSCOMGlue.c
src/vbox/vbox_XPCOMCGlue.c

7
src/Makefile.am
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@ -98,7 +98,8 @@ UTIL_SOURCES = \
util/virnetdevtap.h util/virnetdevtap.c \
util/virnetdevveth.h util/virnetdevveth.c \
util/virnetdevvportprofile.h util/virnetdevvportprofile.c \
util/virsocketaddr.h util/virsocketaddr.c
util/virsocketaddr.h util/virsocketaddr.c \
util/virtime.h util/virtime.c
EXTRA_DIST += $(srcdir)/util/virkeymaps.h $(srcdir)/util/keymaps.csv \
$(srcdir)/util/virkeycode-mapgen.py
@ -562,7 +563,8 @@ libvirt_util_la_SOURCES = \
libvirt_util_la_CFLAGS = $(CAPNG_CFLAGS) $(YAJL_CFLAGS) $(LIBNL_CFLAGS) \
$(AM_CFLAGS) $(AUDIT_CFLAGS) $(DEVMAPPER_CFLAGS)
libvirt_util_la_LIBADD = $(CAPNG_LIBS) $(YAJL_LIBS) $(LIBNL_LIBS) \
$(THREAD_LIBS) $(AUDIT_LIBS) $(DEVMAPPER_LIBS)
$(THREAD_LIBS) $(AUDIT_LIBS) $(DEVMAPPER_LIBS) \
$(RT_LIBS)
noinst_LTLIBRARIES += libvirt_conf.la
@ -1501,6 +1503,7 @@ libvirt_lxc_LDFLAGS = $(WARN_CFLAGS) $(AM_LDFLAGS)
libvirt_lxc_LDADD = $(CAPNG_LIBS) $(YAJL_LIBS) \
$(LIBXML_LIBS) $(NUMACTL_LIBS) $(THREAD_LIBS) \
$(LIBNL_LIBS) $(AUDIT_LIBS) $(DEVMAPPER_LIBS) \
$(RT_LIBS) \
../gnulib/lib/libgnu.la
if WITH_DTRACE
libvirt_lxc_LDADD += probes.o

11
src/libvirt_private.syms
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@ -1387,6 +1387,17 @@ virKeycodeSetTypeFromString;
virKeycodeValueFromString;
virKeycodeValueTranslate;
# virtime.h
virTimeMillisNow;
virTimeFieldsNow;
virTimeFieldsThen;
virTimeStringNow;
virTimeStringThen;
virTimeStringNewNow;
virTimeStringNewThen;
# xml.h
virXMLParseHelper;
virXMLPropString;

350
src/util/virtime.c Normal file
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@ -0,0 +1,350 @@
/*
* virtime.c: Time handling functions
*
* Copyright (C) 2006-2011 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Daniel P. Berrange <berrange@redhat.com>
*
* The intent is that this file provides a set of time APIs which
* are async signal safe, to allow use in between fork/exec eg by
* the logging code.
*
* The reality is that wsnprintf is technically unsafe. We ought
* to roll out our int -> str conversions to avoid this.
*
* We do *not* use regular libvirt error APIs for most of the code,
* since those are not async signal safe, and we dont want logging
* APIs generating timestamps to blow away real errors
*/
#include <config.h>
#include <stdio.h>
#ifndef HAVE_CLOCK_GETTIME
# include <sys/time.h>
#endif
#include "virtime.h"
#include "util.h"
#include "memory.h"
#include "virterror_internal.h"
#define VIR_FROM_THIS VIR_FROM_NONE
/* We prefer clock_gettime if available because that is officially
* async signal safe according to POSIX. Many platforms lack it
* though, so fallback to gettimeofday everywhere else
*/
/**
* virTimeMillisNowRaw:
* @now: filled with current time in milliseconds
*
* Retrieves the current system time, in milliseconds since the
* epoch
*
* Returns 0 on success, -1 on error with errno set
*/
int virTimeMillisNowRaw(unsigned long long *now)
{
#ifdef HAVE_CLOCK_GETTIME
struct timespec ts;
if (clock_gettime(CLOCK_REALTIME, &ts) < 0)
return -1;
*now = (ts.tv_sec * 1000ull) + (ts.tv_nsec / (1000ull * 1000ull));
#else
struct timeval tv;
if (gettimeofday(&tv, NULL) < 0)
return -1;
*now = (tv.tv_sec * 1000ull) + (tv.tv_usec / 1000ull);
#endif
return 0;
}
/**
* virTimeFieldsNowRaw:
* @fields: filled with current time fields
*
* Retrieves the current time, in broken-down field format.
* The time is always in UTC.
*
* Returns 0 on success, -1 on error with errno set
*/
int virTimeFieldsNowRaw(struct tm *fields)
{
unsigned long long now;
if (virTimeMillisNowRaw(&now) < 0)
return -1;
return virTimeFieldsThenRaw(now, fields);
}
#define SECS_PER_HOUR (60 * 60)
#define SECS_PER_DAY (SECS_PER_HOUR * 24)
#define DIV(a, b) ((a) / (b) - ((a) % (b) < 0))
#define LEAPS_THRU_END_OF(y) (DIV (y, 4) - DIV (y, 100) + DIV (y, 400))
const unsigned short int __mon_yday[2][13] = {
/* Normal years. */
{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
/* Leap years. */
{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
};
/**
* virTimeFieldsThenRaw:
* @when: the time to convert in milliseconds
* @fields: filled with time @when fields
*
* Converts the timestamp @when into broken-down field format.
* Time time is always in UTC
*
* Returns 0 on success, -1 on error with errno set
*/
int virTimeFieldsThenRaw(unsigned long long when, struct tm *fields)
{
/* This code is taken from GLibC under terms of LGPLv2+ */
long int days, rem, y;
const unsigned short int *ip;
unsigned long long whenSecs = when / 1000ull;
unsigned int offset = 0; /* We hardcoded GMT */
days = whenSecs / SECS_PER_DAY;
rem = whenSecs % SECS_PER_DAY;
rem += offset;
while (rem < 0) {
rem += SECS_PER_DAY;
--days;
}
while (rem >= SECS_PER_DAY) {
rem -= SECS_PER_DAY;
++days;
}
fields->tm_hour = rem / SECS_PER_HOUR;
rem %= SECS_PER_HOUR;
fields->tm_min = rem / 60;
fields->tm_sec = rem % 60;
/* January 1, 1970 was a Thursday. */
fields->tm_wday = (4 + days) % 7;
if (fields->tm_wday < 0)
fields->tm_wday += 7;
y = 1970;
while (days < 0 || days >= (__isleap (y) ? 366 : 365)) {
/* Guess a corrected year, assuming 365 days per year. */
long int yg = y + days / 365 - (days % 365 < 0);
/* Adjust DAYS and Y to match the guessed year. */
days -= ((yg - y) * 365
+ LEAPS_THRU_END_OF (yg - 1)
- LEAPS_THRU_END_OF (y - 1));
y = yg;
}
fields->tm_year = y - 1900;
fields->tm_yday = days;
ip = __mon_yday[__isleap(y)];
for (y = 11; days < (long int) ip[y]; --y)
continue;
days -= ip[y];
fields->tm_mon = y;
fields->tm_mday = days + 1;
return 0;
}
/**
* virTimeStringNowRaw:
* @buf: a buffer at least VIR_TIME_STRING_BUFLEN in length
*
* Initializes @buf to contain a formatted timestamp
* corresponding to the current time.
*
* Returns 0 on success, -1 on error
*/
int virTimeStringNowRaw(char *buf)
{
unsigned long long now;
if (virTimeMillisNowRaw(&now) < 0)
return -1;
return virTimeStringThenRaw(now, buf);
}
/**
* virTimeStringThenRaw:
* @when: the time to format in milliseconds
* @buf: a buffer at least VIR_TIME_STRING_BUFLEN in length
*
* Initializes @buf to contain a formatted timestamp
* corresponding to the time @when.
*
* Returns 0 on success, -1 on error
*/
int virTimeStringThenRaw(unsigned long long when, char *buf)
{
struct tm fields;
if (virTimeFieldsThenRaw(when, &fields) < 0)
return -1;
fields.tm_year += 1900;
fields.tm_mon += 1;
if (snprintf(buf, VIR_TIME_STRING_BUFLEN,
"%4d-%02d-%02d %02d:%02d:%02d.%03d+0000",
fields.tm_year, fields.tm_mon, fields.tm_mday,
fields.tm_hour, fields.tm_min, fields.tm_sec,
(int) (when % 1000)) >= VIR_TIME_STRING_BUFLEN) {
errno = ERANGE;
return -1;
}
return 0;
}
/**
* virTimeMillisNow:
* @now: filled with current time in milliseconds
*
* Retrieves the current system time, in milliseconds since the
* epoch
*
* Returns 0 on success, -1 on error with error reported
*/
int virTimeMillisNow(unsigned long long *now)
{
if (virTimeMillisNowRaw(now) < 0) {
virReportSystemError(errno, "%s",
_("Unable to get current time"));
return -1;
}
return 0;
}
/**
* virTimeFieldsNowRaw:
* @fields: filled with current time fields
*
* Retrieves the current time, in broken-down field format.
* The time is always in UTC.
*
* Returns 0 on success, -1 on error with errno reported
*/
int virTimeFieldsNow(struct tm *fields)
{
unsigned long long now;
if (virTimeMillisNow(&now) < 0)
return -1;
return virTimeFieldsThen(now, fields);
}
/**
* virTimeFieldsThen:
* @when: the time to convert in milliseconds
* @fields: filled with time @when fields
*
* Converts the timestamp @when into broken-down field format.
* Time time is always in UTC
*
* Returns 0 on success, -1 on error with error reported
*/
int virTimeFieldsThen(unsigned long long when, struct tm *fields)
{
if (virTimeFieldsThenRaw(when, fields) < 0) {
virReportSystemError(errno, "%s",
_("Unable to break out time format"));
return -1;
}
return 0;
}
/**
* virTimeStringNow:
*
* Creates a string containing a formatted timestamp
* corresponding to the current time.
*
* This function is not async signal safe
*
* Returns a formatted allocated string, or NULL on error
*/
char *virTimeStringNow(void)
{
char *ret;
if (VIR_ALLOC_N(ret, VIR_TIME_STRING_BUFLEN) < 0) {
virReportOOMError();
return NULL;
}
if (virTimeStringNowRaw(ret) < 0) {
virReportSystemError(errno, "%s",
_("Unable to format time"));
VIR_FREE(ret);
return NULL;
}
return ret;
}
/**
* virTimeStringThen:
* @when: the time to format in milliseconds
*
* Creates a string containing a formatted timestamp
* corresponding to the time @when.
*
* This function is not async signal safe
*
* Returns a formatted allocated string, or NULL on error
*/
char *virTimeStringThen(unsigned long long when)
{
char *ret;
if (VIR_ALLOC_N(ret, VIR_TIME_STRING_BUFLEN) < 0) {
virReportOOMError();
return NULL;
}
if (virTimeStringThenRaw(when, ret) < 0) {
virReportSystemError(errno, "%s",
_("Unable to format time"));
VIR_FREE(ret);
return NULL;
}
return ret;
}

67
src/util/virtime.h Normal file
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@ -0,0 +1,67 @@
/*
* virtime.h: Time handling functions
*
* Copyright (C) 2006-2011 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Daniel P. Berrange <berrange@redhat.com>
*/
#ifndef __VIR_TIME_H__
# define __VIR_TIME_H__
# include <time.h>
# include "internal.h"
/* The format string we intend to use is:
*
* Yr Mon Day Hour Min Sec Ms TZ
* %4d-%02d-%02d %02d:%02d:%02d.%03d+0000
*
*/
# define VIR_TIME_STRING_BUFLEN \
(4 + 1 + 2 + 1 + 2 + 1 + 2 + 1 + 2 + 1 + 2 + 1 + 3 + 5 + 1)
/* Yr Mon Day Hour Min Sec Ms TZ NULL */
/* These APIs are async signal safe and return -1, setting
* errno on failure */
int virTimeMillisNowRaw(unsigned long long *now)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
int virTimeFieldsNowRaw(struct tm *fields)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
int virTimeFieldsThenRaw(unsigned long long when, struct tm *fields)
ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
int virTimeStringNowRaw(char *buf)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
int virTimeStringThenRaw(unsigned long long when, char *buf)
ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
/* These APIs are *not* async signal safe and return -1,
* raising a libvirt error on failure
*/
int virTimeMillisNow(unsigned long long *now)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
int virTimeFieldsNow(struct tm *fields)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
int virTimeFieldsThen(unsigned long long when, struct tm *fields)
ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
char *virTimeStringNow(void);
char *virTimeStringThen(unsigned long long when);
#endif

1
tests/.gitignore vendored
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@ -36,6 +36,7 @@ virnetmessagetest
virnetsockettest
virnettlscontexttest
virshtest
virtimetest
vmx2xmltest
xencapstest
xmconfigtest

9
tests/Makefile.am
View File

@ -96,7 +96,8 @@ check_PROGRAMS = virshtest conftest sockettest \
nodeinfotest qparamtest virbuftest \
commandtest commandhelper seclabeltest \
hashtest virnetmessagetest virnetsockettest ssh \
utiltest virnettlscontexttest shunloadtest
utiltest virnettlscontexttest shunloadtest \
virtimetest
check_LTLIBRARIES = libshunload.la
@ -217,6 +218,7 @@ TESTS = virshtest \
virnetmessagetest \
virnetsockettest \
virnettlscontexttest \
virtimetest \
shunloadtest \
utiltest \
$(test_scripts)
@ -495,6 +497,11 @@ else
EXTRA_DIST += pkix_asn1_tab.c
endif
virtimetest_SOURCES = \
virtimetest.c testutils.h testutils.c
virtimetest_CFLAGS = -Dabs_builddir="\"$(abs_builddir)\"" $(AM_CFLAGS)
virtimetest_LDADD = ../src/libvirt-net-rpc.la $(LDADDS)
seclabeltest_SOURCES = \
seclabeltest.c

124
tests/virtimetest.c Normal file
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@ -0,0 +1,124 @@
/*
* Copyright (C) 2011 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Daniel P. Berrange <berrange@redhat.com>
*/
#include <config.h>
#include <stdlib.h>
#include <signal.h>
#include "testutils.h"
#include "util.h"
#include "virterror_internal.h"
#include "memory.h"
#include "logging.h"
#include "virtime.h"
#define VIR_FROM_THIS VIR_FROM_RPC
struct testTimeFieldsData {
unsigned long long when;
struct tm fields;
};
static int testTimeFields(const void *args)
{
const struct testTimeFieldsData *data = args;
struct tm actual;
if (virTimeFieldsThen(data->when, &actual) < 0)
return -1;
#define COMPARE(field) \
do { \
if (data->fields.field != actual.field) { \
VIR_DEBUG("Expect " #field " %d got %d", \
data->fields.field, actual.field); \
return -1; \
} \
} while (0)
/* tm_year value 0 is based off epoch 1900 */
actual.tm_year += 1900;
/* tm_mon is range 0-11, but we want 1-12 */
actual.tm_mon += 1;
COMPARE(tm_year);
COMPARE(tm_mon);
COMPARE(tm_mday);
COMPARE(tm_hour);
COMPARE(tm_min);
COMPARE(tm_sec);
return 0;
}
static int
mymain(void)
{
int ret = 0;
signal(SIGPIPE, SIG_IGN);
#define TEST_FIELDS(ts, year, mon, day, hour, min, sec) \
do { \
struct testTimeFieldsData data = { \
.when = ts, \
.fields = { \
.tm_year = year, \
.tm_mon = mon, \
.tm_mday = day, \
.tm_hour = hour, \
.tm_min = min, \
.tm_sec = sec, \
.tm_wday = 0, \
.tm_yday = 0, \
.tm_isdst = 0, \
}, \
}; \
if (virtTestRun("Test fields " #ts " " #year " ", 1, testTimeFields, &data) < 0) \
ret = -1; \
} while (0)
TEST_FIELDS( 0ull, 1970, 1, 1, 0, 0, 0);
TEST_FIELDS( 5000ull, 1970, 1, 1, 0, 0, 5);
TEST_FIELDS( 3605000ull, 1970, 1, 1, 1, 0, 5);
TEST_FIELDS( 86405000ull, 1970, 1, 2, 0, 0, 5);
TEST_FIELDS( 31536000000ull, 1971, 1, 1, 0, 0, 0);
TEST_FIELDS( 30866399000ull, 1970, 12, 24, 5, 59, 59);
TEST_FIELDS( 123465599000ull, 1973, 11, 29, 23, 59, 59);
TEST_FIELDS( 155001599000ull, 1974, 11, 29, 23, 59, 59);
TEST_FIELDS( 186537599000ull, 1975, 11, 29, 23, 59, 59);
TEST_FIELDS( 344390399000ull, 1980, 11, 29, 23, 59, 59);
TEST_FIELDS(1203161493000ull, 2008, 2, 16, 11, 31, 33);
TEST_FIELDS(1234567890000ull, 2009, 2, 13, 23, 31, 30);
TEST_FIELDS(1322524800000ull, 2011, 11, 29, 0, 0, 0);
TEST_FIELDS(1322611199000ull, 2011, 11, 29, 23, 59, 59);
TEST_FIELDS(2147483648000ull, 2038, 1, 19, 3, 14, 8);
return (ret==0 ? EXIT_SUCCESS : EXIT_FAILURE);
}
VIRT_TEST_MAIN(mymain)