incubator-nuttx/libs/libc/unistd/lib_gethostname.c

121 lines
4.7 KiB
C

/****************************************************************************
* libs/libc/unistd/lib_gethostname.c
*
* Copyright (C) 2015 Stavros Polymenis. All rights reserved.
* Copyright (C) 2015, 2016 Gregory Nutt. All rights reserved.
* Author: Stavros Polymenis <sp@orbitalfox.com>
* Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <string.h>
#include <unistd.h>
#include <nuttx/irq.h>
/* Further, in the protected and kernel build modes where kernel and
* application code are separated, the hostname is a common system property
* and must reside only in the kernel. In that case, this accessor
* function only be called from user space is only via a kernel system call.
*/
#if defined(CONFIG_BUILD_FLAT) || defined(__KERNEL__)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* The default host name is a system configuration setting. This may be
* changed via sethostname(), however.
*/
#ifndef CONFIG_LIBC_HOSTNAME
# define CONFIG_LIBC_HOSTNAME ""
#endif
/****************************************************************************
* Public Data
****************************************************************************/
/* This is the system hostname */
char g_hostname[HOST_NAME_MAX + 1] = CONFIG_LIBC_HOSTNAME;
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: gethostname
*
* Description:
* The gethostname() function will return the standard host name for the
* current machine. The namelen argument will specify the size of the
* array pointed to by the name argument. The returned name will be null-
* terminated, except that if namelen is an insufficient length to hold the
* host name, then the returned name will be truncated and it is
* unspecified whether the returned name is null-terminated.
*
* Host names are limited to {HOST_NAME_MAX} bytes.
*
* Input Parameters:
* name - The user-provided buffer to receive the host name.
* namelen - The size of the user provided buffer in bytes.
*
* Returned Value:
* Upon successful completion, 0 will be returned; otherwise, -1 will be
* returned. No errors are defined; errno variable is not set.
*
****************************************************************************/
int gethostname(FAR char *name, size_t namelen)
{
irqstate_t flags;
/* Return the host name, truncating to fit into the user provided buffer.
* The hostname is global resource. There is a microscopic possibility
* that it could change while we are copying it.
*/
flags = enter_critical_section();
strncpy(name, g_hostname, namelen);
leave_critical_section(flags);
return 0;
}
#endif /* CONFIG_BUILD_FLAT || __KERNEL__ */