| 1 | /* vi: set sw=4 ts=4: */
|
|---|
| 2 | /*
|
|---|
| 3 | * Safe gethostname implementation for busybox
|
|---|
| 4 | *
|
|---|
| 5 | * Copyright (C) 2008 Tito Ragusa <farmatito@tiscali.it>
|
|---|
| 6 | *
|
|---|
| 7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
|
|---|
| 8 | */
|
|---|
| 9 |
|
|---|
| 10 | /*
|
|---|
| 11 | * SUSv2 guarantees that "Host names are limited to 255 bytes"
|
|---|
| 12 | * POSIX.1-2001 guarantees that "Host names (not including the terminating
|
|---|
| 13 | * null byte) are limited to HOST_NAME_MAX bytes" (64 bytes on my box).
|
|---|
| 14 | *
|
|---|
| 15 | * RFC1123 says:
|
|---|
| 16 | *
|
|---|
| 17 | * The syntax of a legal Internet host name was specified in RFC-952
|
|---|
| 18 | * [DNS:4]. One aspect of host name syntax is hereby changed: the
|
|---|
| 19 | * restriction on the first character is relaxed to allow either a
|
|---|
| 20 | * letter or a digit. Host software MUST support this more liberal
|
|---|
| 21 | * syntax.
|
|---|
| 22 | *
|
|---|
| 23 | * Host software MUST handle host names of up to 63 characters and
|
|---|
| 24 | * SHOULD handle host names of up to 255 characters.
|
|---|
| 25 | */
|
|---|
| 26 |
|
|---|
| 27 | #include "libbb.h"
|
|---|
| 28 | #include <sys/utsname.h>
|
|---|
| 29 |
|
|---|
| 30 | /*
|
|---|
| 31 | * On success return the current malloced and NUL terminated hostname.
|
|---|
| 32 | * On error return malloced and NUL terminated string "?".
|
|---|
| 33 | * This is an illegal first character for a hostname.
|
|---|
| 34 | * The returned malloced string must be freed by the caller.
|
|---|
| 35 | */
|
|---|
| 36 | char* FAST_FUNC safe_gethostname(void)
|
|---|
| 37 | {
|
|---|
| 38 | struct utsname uts;
|
|---|
| 39 |
|
|---|
| 40 | /* The length of the arrays in a struct utsname is unspecified;
|
|---|
| 41 | * the fields are terminated by a null byte.
|
|---|
| 42 | * Note that there is no standard that says that the hostname
|
|---|
| 43 | * set by sethostname(2) is the same string as the nodename field of the
|
|---|
| 44 | * struct returned by uname (indeed, some systems allow a 256-byte host-
|
|---|
| 45 | * name and an 8-byte nodename), but this is true on Linux. The same holds
|
|---|
| 46 | * for setdomainname(2) and the domainname field.
|
|---|
| 47 | */
|
|---|
| 48 |
|
|---|
| 49 | /* Uname can fail only if you pass a bad pointer to it. */
|
|---|
| 50 | uname(&uts);
|
|---|
| 51 | return xstrndup(!uts.nodename[0] ? "?" : uts.nodename, sizeof(uts.nodename));
|
|---|
| 52 | }
|
|---|
| 53 |
|
|---|
| 54 | /*
|
|---|
| 55 | * On success return the current malloced and NUL terminated domainname.
|
|---|
| 56 | * On error return malloced and NUL terminated string "?".
|
|---|
| 57 | * This is an illegal first character for a domainname.
|
|---|
| 58 | * The returned malloced string must be freed by the caller.
|
|---|
| 59 | */
|
|---|
| 60 | char* FAST_FUNC safe_getdomainname(void)
|
|---|
| 61 | {
|
|---|
| 62 | #if defined(__linux__)
|
|---|
| 63 | /* The field domainname of struct utsname is Linux specific. */
|
|---|
| 64 | struct utsname uts;
|
|---|
| 65 | uname(&uts);
|
|---|
| 66 | return xstrndup(!uts.domainname[0] ? "?" : uts.domainname, sizeof(uts.domainname));
|
|---|
| 67 | #else
|
|---|
| 68 | /* We really don't care about people with domain names wider than most screens */
|
|---|
| 69 | char buf[256];
|
|---|
| 70 | int r = getdomainname(buf, sizeof(buf));
|
|---|
| 71 | buf[sizeof(buf)-1] = '\0';
|
|---|
| 72 | return xstrdup(r < 0 ? "?" : buf);
|
|---|
| 73 | #endif
|
|---|
| 74 | }
|
|---|
