mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-29 22:11:18 +00:00
120 lines
3.1 KiB
C
120 lines
3.1 KiB
C
/* Copyright (C) 1995-2015 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C 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.
|
|
|
|
The GNU C 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 the GNU C Library; if not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <alloca.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <unistd.h>
|
|
#include <netdb.h>
|
|
#include <not-cancel.h>
|
|
|
|
#define HOSTIDFILE "/etc/hostid"
|
|
|
|
#ifdef SET_PROCEDURE
|
|
int
|
|
sethostid (id)
|
|
long int id;
|
|
{
|
|
int fd;
|
|
ssize_t written;
|
|
int32_t id32 = id;
|
|
|
|
/* Test for appropriate rights to set host ID. */
|
|
if (__libc_enable_secure)
|
|
{
|
|
__set_errno (EPERM);
|
|
return -1;
|
|
}
|
|
|
|
/* Make sure the ID is not too large. Needed for bi-arch support. */
|
|
if (id32 != id)
|
|
{
|
|
__set_errno (EOVERFLOW);
|
|
return -1;
|
|
}
|
|
|
|
/* Open file for writing. Everybody is allowed to read this file. */
|
|
fd = open_not_cancel (HOSTIDFILE, O_CREAT|O_WRONLY|O_TRUNC, 0644);
|
|
if (fd < 0)
|
|
return -1;
|
|
|
|
written = write_not_cancel (fd, &id32, sizeof (id32));
|
|
|
|
close_not_cancel_no_status (fd);
|
|
|
|
return written != sizeof (id32) ? -1 : 0;
|
|
}
|
|
|
|
#else
|
|
# include <string.h>
|
|
# include <sys/param.h>
|
|
# include <resolv/netdb.h>
|
|
# include <netinet/in.h>
|
|
|
|
long int
|
|
gethostid (void)
|
|
{
|
|
char hostname[MAXHOSTNAMELEN + 1];
|
|
size_t buflen;
|
|
char *buffer;
|
|
struct hostent hostbuf, *hp;
|
|
int32_t id;
|
|
struct in_addr in;
|
|
int herr;
|
|
int fd;
|
|
|
|
/* First try to get the ID from a former invocation of sethostid. */
|
|
fd = open_not_cancel (HOSTIDFILE, O_RDONLY|O_LARGEFILE, 0);
|
|
if (fd >= 0)
|
|
{
|
|
ssize_t n = read_not_cancel (fd, &id, sizeof (id));
|
|
|
|
close_not_cancel_no_status (fd);
|
|
|
|
if (n == sizeof (id))
|
|
return id;
|
|
}
|
|
|
|
/* Getting from the file was not successful. An intelligent guess for
|
|
a unique number of a host is its IP address. Return this. */
|
|
if (__gethostname (hostname, MAXHOSTNAMELEN) < 0 || hostname[0] == '\0')
|
|
/* This also fails. Return and arbitrary value. */
|
|
return 0;
|
|
|
|
buflen = 1024;
|
|
buffer = __alloca (buflen);
|
|
|
|
/* To get the IP address we need to know the host name. */
|
|
while (__gethostbyname_r (hostname, &hostbuf, buffer, buflen, &hp, &herr)
|
|
!= 0
|
|
|| hp == NULL)
|
|
if (herr != NETDB_INTERNAL || errno != ERANGE)
|
|
return 0;
|
|
else
|
|
/* Enlarge buffer. */
|
|
buffer = extend_alloca (buffer, buflen, 2 * buflen);
|
|
|
|
in.s_addr = 0;
|
|
memcpy (&in, hp->h_addr,
|
|
(int) sizeof (in) < hp->h_length ? (int) sizeof (in) : hp->h_length);
|
|
|
|
/* For the return value to be not exactly the IP address we do some
|
|
bit fiddling. */
|
|
return (int32_t) (in.s_addr << 16 | in.s_addr >> 16);
|
|
}
|
|
#endif
|