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/* Copyright (C) 2003-2007 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, version 2,
* as published by the Free Software Foundation.
*
* 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, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <sys/stat.h>
#include <stdio.h>
int main (void)
{
struct stat st;
long int n;
errno = 0;
/*
* access() returns -1 if the file does not exist or upon error.
* We should display the deprecation warning only when we are sure the
* file does not exist. In case of different error, silently ignore it
* and do not print anything - to not pollute users' scripts unnecessarily.
*/
if (access("/etc/sysconfig/disable-deprecation-warnings", F_OK) == -1
&& errno == ENOENT) {
fprintf(stderr, "warning: genhostid is now deprecated, and will be removed in the near future!\n"
"warning: use systemd-machine-id-setup (1) instead! More info: 'man 5 machine-id'\n");
}
/*
* NOTE: gethostid() always returns 32-bit identifier, and st_size field
* of stat structure represents total size of file, in bytes.
*/
if (stat ("/etc/hostid", &st) == 0 &&
S_ISREG (st.st_mode) && st.st_size == 4) {
return 0;
}
int fd = open ("/dev/random", O_RDONLY);
if (fd == -1 || read (fd, &n, sizeof (n)) != sizeof (n)) {
srand48 ((long int) time (NULL) ^ (long int) getpid ());
n = lrand48 ();
}
return sethostid ((int32_t) n);
}
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