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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "dns-def.h"
#include "dns-domain.h"
#include "hostname-util.h"
#include "idn-util.h"
#include "resolved-util.h"
#include "utf8.h"
int resolve_system_hostname(char **full_hostname, char **first_label) {
_cleanup_free_ char *h = NULL, *n = NULL;
#if HAVE_LIBIDN2
_cleanup_free_ char *utf8 = NULL;
#elif HAVE_LIBIDN
int k;
#endif
char label[DNS_LABEL_MAX+1];
const char *p, *decoded;
int r;
/* Return the full hostname in *full_hostname, if nonnull.
*
* Extract and normalize the first label of the locally configured hostname, check it's not
* "localhost", and return it in *first_label, if nonnull. */
r = gethostname_strict(&h);
if (r < 0)
return log_debug_errno(r, "Can't determine system hostname: %m");
p = h;
r = dns_label_unescape(&p, label, sizeof label, 0);
if (r < 0)
return log_debug_errno(r, "Failed to unescape hostname: %m");
if (r == 0)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"Couldn't find a single label in hostname.");
#if HAVE_LIBIDN || HAVE_LIBIDN2
r = dlopen_idn();
if (r < 0) {
log_debug_errno(r, "Failed to initialize IDN support, ignoring: %m");
decoded = label; /* no decoding */
} else
#endif
{
#if HAVE_LIBIDN2
r = sym_idn2_to_unicode_8z8z(label, &utf8, 0);
if (r != IDN2_OK)
return log_debug_errno(SYNTHETIC_ERRNO(EUCLEAN),
"Failed to undo IDNA: %s", sym_idn2_strerror(r));
assert(utf8_is_valid(utf8));
r = strlen(utf8);
decoded = utf8;
#elif HAVE_LIBIDN
k = dns_label_undo_idna(label, r, label, sizeof label);
if (k < 0)
return log_debug_errno(k, "Failed to undo IDNA: %m");
if (k > 0)
r = k;
if (!utf8_is_valid(label))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"System hostname is not UTF-8 clean.");
decoded = label;
#else
decoded = label; /* no decoding */
#endif
}
r = dns_label_escape_new(decoded, r, &n);
if (r < 0)
return log_debug_errno(r, "Failed to escape hostname: %m");
if (is_localhost(n))
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"System hostname is 'localhost', ignoring.");
if (full_hostname)
*full_hostname = TAKE_PTR(h);
if (first_label)
*first_label = TAKE_PTR(n);
return 0;
}
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