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/* sethostname emulation for glibc compliance.
Copyright (C) 2011-2013 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
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, see <http://www.gnu.org/licenses/>. */
/* Ben Walton <bwalton@artsci.utoronto.ca> */
#include <config.h>
#if !((defined _WIN32 || defined __WIN32__) || defined __CYGWIN__)
/* Unix API. */
/* Specification. */
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <limits.h>
/* Set up to LEN chars of NAME as system hostname.
Return 0 if ok, set errno and return -1 on error. */
int
sethostname (const char *name, size_t len)
{
/* Ensure the string isn't too long. glibc does allow setting an
empty hostname so no point in enforcing a lower bound. */
if (len > HOST_NAME_MAX)
{
errno = EINVAL;
return -1;
}
#ifdef __minix /* Minix */
{
FILE *hostf;
int r = 0;
/* glibc returns EFAULT, EINVAL, and EPERM on error. None of
these are appropriate for us to set, even if they may match the
situation, during failed open/write/close operations, so we
leave errno alone and rely on what the system sets up. */
hostf = fopen ("/etc/hostname.file", "w");
if (hostf == NULL)
r = -1;
else
{
fprintf (hostf, "%.*s\n", (int) len, name);
if (ferror (hostf))
{
/* Close hostf, preserving the errno from the fprintf call. */
int saved_errno = errno;
fclose (hostf);
errno = saved_errno;
r = -1;
}
else
{
if (fclose (hostf))
/* fclose sets errno on failure. */
r = -1;
}
}
return r;
}
#else
/* For platforms that we don't have a better option for, simply bail
out. */
errno = ENOSYS;
return -1;
#endif
}
#else
/* Native Windows API. Also used on Cygwin. */
/* Ensure that <windows.h> declares SetComputerNameEx. */
#undef _WIN32_WINNT
#define _WIN32_WINNT 0x500
#define WIN32_LEAN_AND_MEAN
/* Specification. */
#include <unistd.h>
#include <errno.h>
#include <limits.h>
#include <string.h>
#include <windows.h>
/* The mingw header files don't define GetComputerNameEx, SetComputerNameEx. */
#ifndef GetComputerNameEx
# define GetComputerNameEx GetComputerNameExA
#endif
#ifndef SetComputerNameEx
# define SetComputerNameEx SetComputerNameExA
#endif
/* Set up to LEN chars of NAME as system hostname.
Return 0 if ok, set errno and return -1 on error. */
int
sethostname (const char *name, size_t len)
{
char name_asciz[HOST_NAME_MAX + 1];
char old_name[HOST_NAME_MAX + 1];
DWORD old_name_len;
/* Ensure the string isn't too long. glibc does allow setting an
empty hostname so no point in enforcing a lower bound. */
if (len > HOST_NAME_MAX)
{
errno = EINVAL;
return -1;
}
/* Prepare a NUL-terminated copy of name. */
memcpy (name_asciz, name, len);
name_asciz[len] = '\0';
/* Save the old NetBIOS name. */
old_name_len = sizeof (old_name) - 1;
if (! GetComputerNameEx (ComputerNamePhysicalNetBIOS,
old_name, &old_name_len))
old_name_len = 0;
/* Set both the NetBIOS and the first part of the IP / DNS name. */
if (! SetComputerNameEx (ComputerNamePhysicalNetBIOS, name_asciz))
{
errno = (GetLastError () == ERROR_ACCESS_DENIED ? EPERM : EINVAL);
return -1;
}
if (! SetComputerNameEx (ComputerNamePhysicalDnsHostname, name_asciz))
{
errno = (GetLastError () == ERROR_ACCESS_DENIED ? EPERM : EINVAL);
/* Restore the old NetBIOS name. */
if (old_name_len > 0)
{
old_name[old_name_len] = '\0';
SetComputerNameEx (ComputerNamePhysicalNetBIOS, old_name);
}
return -1;
}
/* Note that the new host name becomes effective only after a reboot! */
return 0;
}
#endif
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