mirror of
https://github.com/jart/cosmopolitan.git
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77 lines
3.7 KiB
C
77 lines
3.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/calls/strace.internal.h"
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#include "libc/calls/syscall_support-sysv.internal.h"
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#include "libc/dce.h"
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#include "libc/intrin/kprintf.h"
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#include "libc/nt/enum/computernameformat.h"
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#include "libc/sysv/errfuns.h"
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#define KERN_HOSTNAME 10
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/**
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* Returns name of current host.
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*
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* For example, if the fully-qualified hostname is "host.domain.example"
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* then this SHOULD return "host" however that might not be the case; it
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* depends on how the host machine is configured. It's fair to say if it
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* has a dot, it's a FQDN, otherwise it's a node.
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*
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* The nul / mutation semantics are tricky. Here is some safe copypasta:
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*
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* char host[254];
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* if (gethostname(host, sizeof(host))) {
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* strcpy(host, "localhost");
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* }
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*
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* On Linux this is the same as `/proc/sys/kernel/hostname`.
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*
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* @param name receives output name, which is guaranteed to be complete
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* and have a nul-terminator if this function return zero
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* @param len is size of `name` consider using `DNS_NAME_MAX + 1` (254)
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* @raise EINVAL if `len` is negative
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* @raise EFAULT if `name` is an invalid address
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* @raise ENAMETOOLONG if the underlying system call succeeded, but the
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* returned hostname had a length equal to or greater than `len` in
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* which case this error is raised and the buffer is modified, with
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* as many bytes of hostname as possible excluding a nul-terminator
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* @return 0 on success, or -1 w/ errno
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*/
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int gethostname(char *name, size_t len) {
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int rc;
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if (len < 0) {
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rc = einval();
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} else if (!len) {
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rc = 0;
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} else if (!name) {
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rc = efault();
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} else if (IsLinux()) {
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rc = gethostname_linux(name, len);
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} else if (IsBsd()) {
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rc = gethostname_bsd(name, len, KERN_HOSTNAME);
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} else if (IsWindows()) {
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rc = gethostname_nt(name, len, kNtComputerNamePhysicalDnsHostname);
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} else {
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rc = enosys();
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}
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STRACE("gethostname([%#.*s], %'zu) → %d% m", len, name, len, rc);
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return rc;
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}
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