mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-07-01 00:38:31 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Improve quality of uname/gethostname/getdomainname

Browse source
This commit is contained in:
Justine Tunney 2022-09-03 19:07:19 -07:00
parent c5c4dfcd21
commit b66bd064d8
13 changed files with 334 additions and 151 deletions
Download patch file Download diff file Expand all files Collapse all files

57
libc/calls/gethostname.c
View file

@ -17,29 +17,60 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/strace.internal.h"
#include "libc/calls/syscall_support-sysv.internal.h"
#include "libc/dce.h"
#include "libc/intrin/kprintf.h"
#include "libc/nt/enum/computernameformat.h"
#include "libc/sysv/errfuns.h"
#define KERN_HOSTNAME 10
/**
* Returns name of host system, e.g.
* Returns name of current host.
*
* pheidippides.domain.example
* ^^^^^^^^^^^^
* For example, if the fully-qualified hostname is "host.domain.example"
* then this SHOULD return "host" however that might not be the case; it
* depends on how the host machine is configured. It's fair to say if it
* has a dot, it's a FQDN, otherwise it's a node.
*
* @return 0 on success or -1 w/ errno
* The nul / mutation semantics are tricky. Here is some safe copypasta:
*
* char host[254];
* if (gethostname(host, sizeof(host))) {
* strcpy(host, "localhost");
* }
*
* On Linux this is the same as `/proc/sys/kernel/hostname`.
*
* @param name receives output name, which is guaranteed to be complete
* and have a nul-terminator if this function return zero
* @param len is size of `name` consider using `DNS_NAME_MAX + 1` (254)
* @raise EINVAL if `len` is negative
* @raise EFAULT if `name` is an invalid address
* @raise ENAMETOOLONG if the underlying system call succeeded, but the
* returned hostname had a length equal to or greater than `len` in
* which case this error is raised and the buffer is modified, with
* as many bytes of hostname as possible excluding a nul-terminator
* @return 0 on success, or -1 w/ errno
*/
int gethostname(char *name, size_t len) {
if (len < 1) return einval();
if (!name) return efault();
if (!IsWindows()) {
if (!IsBsd()) {
return gethostname_linux(name, len);
} else {
return gethostname_bsd(name, len);
}
int rc;
if (len < 0) {
rc = einval();
} else if (!len) {
rc = 0;
} else if (!name) {
rc = efault();
} else if (IsLinux()) {
rc = gethostname_linux(name, len);
} else if (IsBsd()) {
rc = gethostname_bsd(name, len, KERN_HOSTNAME);
} else if (IsWindows()) {
rc = gethostname_nt(name, len, kNtComputerNamePhysicalDnsHostname);
} else {
return gethostname_nt(name, len, kNtComputerNamePhysicalDnsHostname);
rc = enosys();
}
STRACE("gethostname([%#.*s], %'zu) → %d% m", len, name, len, rc);
return rc;
}