| /* 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 |
| } |