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