blob: b22e30ea355c43047fade0ce08510ac92fb94f8c [file] [log] [blame]
/* vi: set sw=4 ts=4: */
* Safe gethostname implementation for busybox
* Copyright (C) 2008 Tito Ragusa <>
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
* SUSv2 guarantees that "Host names are limited to 255 bytes"
* POSIX.1-2001 guarantees that "Host names (not including the terminating
* null byte) are limited to HOST_NAME_MAX bytes" (64 bytes on my box).
* RFC1123 says:
* The syntax of a legal Internet host name was specified in RFC-952
* [DNS:4]. One aspect of host name syntax is hereby changed: the
* restriction on the first character is relaxed to allow either a
* letter or a digit. Host software MUST support this more liberal
* syntax.
* Host software MUST handle host names of up to 63 characters and
* SHOULD handle host names of up to 255 characters.
#include "libbb.h"
#include <sys/utsname.h>
* On success return the current malloced and NUL terminated hostname.
* On error return malloced and NUL terminated string "?".
* This is an illegal first character for a hostname.
* The returned malloced string must be freed by the caller.
char* FAST_FUNC safe_gethostname(void)
struct utsname uts;
/* The length of the arrays in a struct utsname is unspecified;
* the fields are terminated by a null byte.
* Note that there is no standard that says that the hostname
* set by sethostname(2) is the same string as the nodename field of the
* struct returned by uname (indeed, some systems allow a 256-byte host-
* name and an 8-byte nodename), but this is true on Linux. The same holds
* for setdomainname(2) and the domainname field.
/* Uname can fail only if you pass a bad pointer to it. */
return xstrndup(!uts.nodename[0] ? "?" : uts.nodename, sizeof(uts.nodename));