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sortix--sortix/hostname/hostname.c
Jonas 'Sortie' Termansen dbf4bcd6cf Add hostname(1).
2017-03-19 17:33:47 +01:00

104 lines
2.6 KiB
C

/*
* Copyright (c) 2017 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* hostname.c
* Write or set the system hostname.
*/
#include <err.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
// TODO: The Sortix <limits.h> doesn't expose this at the moment.
#if !defined(HOST_NAME_MAX) && defined(__sortix__)
#include <sortix/limits.h>
#endif
static void compact_arguments(int* argc, char*** argv)
{
for ( int i = 0; i < *argc; i++ )
{
while ( i < *argc && !(*argv)[i] )
{
for ( int n = i; n < *argc; n++ )
(*argv)[n] = (*argv)[n+1];
(*argc)--;
}
}
}
int main(int argc, char* argv[])
{
bool short_hostname = false;
const char* argv0 = argv[0];
for ( int i = 1; i < argc; i++ )
{
const char* arg = argv[i];
if ( arg[0] != '-' || !arg[1] )
continue;
argv[i] = NULL;
if ( !strcmp(arg, "--") )
break;
if ( arg[1] != '-' )
{
char c;
while ( (c = *++arg) ) switch ( c )
{
case 's': short_hostname = true; break;
default:
fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
exit(1);
}
}
else if ( !strcmp(arg, "--short") )
short_hostname = true;
else
{
fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
exit(1);
}
}
compact_arguments(&argc, &argv);
if ( 3 <= argc )
errx(1, "unexpected extra operand");
if ( argc == 2 )
{
if ( short_hostname )
errx(1, "the -s option is incompatible with setting hostname");
char* hostname = argv[1];
if ( sethostname(hostname, strlen(hostname)) < 0 )
err(1, "sethostname: %s", hostname);
return 0;
}
char hostname[HOST_NAME_MAX + 1];
if ( gethostname(hostname, sizeof(hostname)) < 0 )
err(1, "gethostname");
if ( short_hostname )
hostname[strcspn(hostname, ".")] = '\0';
puts(hostname);
if ( ferror(stdout) || fflush(stdout) == EOF )
err(1, "stdout");
return 0;
}