libvirt/src/util/virhostuptime.c
Michal Privoznik 070d6969fe virhostuptime: Add linux stub for musl
When we want to know the boot timestamp of the host, we can call
virHostGetBootTime(). Under the hood, it uses getutxid() which is
defined by POSIX and properly check for in configure. However,
musl took a path where it declares the function but instead of
providing any useful implementation it returns NULL meaning "no
record found". If that's the case, use our second best option -
/proc/uptime and a bit of maths.

https://bugzilla.redhat.com/show_bug.cgi?id=1760885

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
2019-11-14 15:20:38 +01:00

138 lines
3.3 KiB
C

/*
* virhostuptime.c: helper APIs for host uptime
*
* Copyright (C) 2019 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, see
* <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#ifdef HAVE_GETUTXID
# include <utmpx.h>
#endif
#include "virhostuptime.h"
#include "viralloc.h"
#include "virfile.h"
#include "virlog.h"
#include "virstring.h"
#include "virtime.h"
#include "virthread.h"
#define VIR_FROM_THIS VIR_FROM_NONE
VIR_LOG_INIT("util.virhostuptime");
static unsigned long long bootTime;
static int bootTimeErrno;
static virOnceControl virHostGetBootTimeOnce = VIR_ONCE_CONTROL_INITIALIZER;
#if defined(__linux__)
# define UPTIME_FILE "/proc/uptime"
static int
virHostGetBootTimeProcfs(unsigned long long *btime)
{
unsigned long long now;
double up;
g_autofree char *buf = NULL;
char *tmp;
if (virTimeMillisNow(&now) < 0)
return -errno;
/* 1KiB limit is more than enough. */
if (virFileReadAll(UPTIME_FILE, 1024, &buf) < 0)
return -errno;
/* buf contains two doubles now:
* $uptime $idle_time
* We're interested only in the first one */
if (!(tmp = strchr(buf, ' '))) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("uptime file has unexpected format '%s'"),
buf);
return -EINVAL;
}
*tmp = '\0';
if (virStrToDouble(buf, NULL, &up) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Unable to parse uptime value '%s'"),
buf);
return -EINVAL;
}
*btime = now / 1000 - up + 0.5;
return 0;
}
#endif /* defined(__linux__) */
#if defined(HAVE_GETUTXID) || defined(__linux__)
static void
virHostGetBootTimeOnceInit(void)
{
# ifdef HAVE_GETUTXID
struct utmpx id = {.ut_type = BOOT_TIME};
struct utmpx *res = NULL;
if (!(res = getutxid(&id))) {
bootTimeErrno = errno;
} else {
bootTime = res->ut_tv.tv_sec;
}
endutxent();
# endif /* HAVE_GETUTXID */
if (bootTimeErrno != 0 || bootTime == 0)
bootTimeErrno = -virHostGetBootTimeProcfs(&bootTime);
}
#else /* !defined(HAVE_GETUTXID) && !defined(__linux__) */
static void
virHostGetBootTimeOnceInit(void)
{
bootTimeErrno = ENOSYS;
}
#endif /* !defined(HAVE_GETUTXID) && !defined(__linux__) */
/**
* virHostGetBootTime:
* @when: UNIX timestamp of boot time
*
* Get a UNIX timestamp of host boot time and store it at @when.
*
* Return: 0 on success,
* -1 otherwise.
*/
int
virHostGetBootTime(unsigned long long *when)
{
if (virOnce(&virHostGetBootTimeOnce, virHostGetBootTimeOnceInit) < 0)
return -1;
if (bootTimeErrno) {
errno = bootTimeErrno;
return -1;
}
*when = bootTime;
return 0;
}