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/* vi: set sw=4 ts=4: */
/*
* Safe gethostname implementation for busybox
*
* Copyright (C) 2008 Tito Ragusa <farmatito@tiscali.it>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
/*
* 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. */
uname(&uts);
return xstrndup(!uts.nodename[0] ? "?" : uts.nodename, sizeof(uts.nodename));
}
/*
* On success return the current malloced and NUL terminated domainname.
* On error return malloced and NUL terminated string "?".
* This is an illegal first character for a domainname.
* The returned malloced string must be freed by the caller.
*/
char* FAST_FUNC safe_getdomainname(void)
{
#if defined(__linux__)
/* The field domainname of struct utsname is Linux specific. */
struct utsname uts;
uname(&uts);
return xstrndup(!uts.domainname[0] ? "?" : uts.domainname, sizeof(uts.domainname));
#else
/* We really don't care about people with domain names wider than most screens */
char buf[256];
int r = getdomainname(buf, sizeof(buf));
buf[sizeof(buf)-1] = '\0';
return xstrdup(r < 0 ? "?" : buf);
#endif
}
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