[thirdparty/systemd.git] / src / nss-myhostname / nss-myhostname.c

/* SPDX-License-Identifier: LGPL-2.1+ */

#include <errno.h>
#include <net/if.h>
#include <netdb.h>
#include <nss.h>
#include <stdlib.h>

#include "alloc-util.h"
#include "errno-util.h"
#include "hostname-util.h"
#include "local-addresses.h"
#include "macro.h"
#include "nss-util.h"
#include "signal-util.h"
#include "string-util.h"

/* We use 127.0.0.2 as IPv4 address. This has the advantage over
 * 127.0.0.1 that it can be translated back to the local hostname. For
 * IPv6 we use ::1 which unfortunately will not translate back to the
 * hostname but instead something like "localhost" or so. */

#define LOCALADDRESS_IPV4 (htobe32(0x7F000002))
#define LOCALADDRESS_IPV6 &in6addr_loopback

NSS_GETHOSTBYNAME_PROTOTYPES(myhostname);
NSS_GETHOSTBYADDR_PROTOTYPES(myhostname);

enum nss_status _nss_myhostname_gethostbyname4_r(
                const char *name,
                struct gaih_addrtuple **pat,
                char *buffer, size_t buflen,
                int *errnop, int *h_errnop,
                int32_t *ttlp) {

        struct gaih_addrtuple *r_tuple, *r_tuple_prev = NULL;
        _cleanup_free_ struct local_address *addresses = NULL;
        _cleanup_free_ char *hn = NULL;
        const char *canonical = NULL;
        int n_addresses = 0;
        uint32_t local_address_ipv4;
        struct local_address *a;
        size_t l, idx, ms;
        char *r_name;
        unsigned n;

        PROTECT_ERRNO;
        BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);

        assert(name);
        assert(pat);
        assert(buffer);
        assert(errnop);
        assert(h_errnop);

        if (is_localhost(name)) {
                /* We respond to 'localhost', so that /etc/hosts
                 * is optional */

                canonical = "localhost";
                local_address_ipv4 = htobe32(INADDR_LOOPBACK);

        } else if (is_gateway_hostname(name)) {

                n_addresses = local_gateways(NULL, 0, AF_UNSPEC, &addresses);
                if (n_addresses <= 0)
                        goto not_found;

                canonical = "_gateway";

        } else {
                hn = gethostname_malloc();
                if (!hn) {
                        UNPROTECT_ERRNO;
                        *errnop = ENOMEM;
                        *h_errnop = NO_RECOVERY;
                        return NSS_STATUS_TRYAGAIN;
                }

                /* We respond to our local hostname, our hostname suffixed with a single dot. */
                if (!streq(name, hn) && !streq_ptr(startswith(name, hn), "."))
                        goto not_found;

                n_addresses = local_addresses(NULL, 0, AF_UNSPEC, &addresses);
                if (n_addresses < 0)
                        n_addresses = 0;

                canonical = hn;
                local_address_ipv4 = LOCALADDRESS_IPV4;
        }

        l = strlen(canonical);
        ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * (n_addresses > 0 ? n_addresses : 2);
        if (buflen < ms) {
                UNPROTECT_ERRNO;
                *errnop = ERANGE;
                *h_errnop = NETDB_INTERNAL;
                return NSS_STATUS_TRYAGAIN;
        }

        /* First, fill in hostname */
        r_name = buffer;
        memcpy(r_name, canonical, l+1);
        idx = ALIGN(l+1);

        assert(n_addresses >= 0);
        if (n_addresses == 0) {
                /* Second, fill in IPv6 tuple */
                r_tuple = (struct gaih_addrtuple*) (buffer + idx);
                r_tuple->next = r_tuple_prev;
                r_tuple->name = r_name;
                r_tuple->family = AF_INET6;
                memcpy(r_tuple->addr, LOCALADDRESS_IPV6, 16);
                r_tuple->scopeid = 0;

                idx += ALIGN(sizeof(struct gaih_addrtuple));
                r_tuple_prev = r_tuple;

                /* Third, fill in IPv4 tuple */
                r_tuple = (struct gaih_addrtuple*) (buffer + idx);
                r_tuple->next = r_tuple_prev;
                r_tuple->name = r_name;
                r_tuple->family = AF_INET;
                *(uint32_t*) r_tuple->addr = local_address_ipv4;
                r_tuple->scopeid = 0;

                idx += ALIGN(sizeof(struct gaih_addrtuple));
                r_tuple_prev = r_tuple;
        }

        /* Fourth, fill actual addresses in, but in backwards order */
        for (a = addresses + n_addresses - 1, n = 0; (int) n < n_addresses; n++, a--) {
                r_tuple = (struct gaih_addrtuple*) (buffer + idx);
                r_tuple->next = r_tuple_prev;
                r_tuple->name = r_name;
                r_tuple->family = a->family;
                r_tuple->scopeid = a->family == AF_INET6 && IN6_IS_ADDR_LINKLOCAL(&a->address.in6) ? a->ifindex : 0;
                memcpy(r_tuple->addr, &a->address, 16);

                idx += ALIGN(sizeof(struct gaih_addrtuple));
                r_tuple_prev = r_tuple;
        }

        /* Verify the size matches */
        assert(idx == ms);

        /* Nscd expects us to store the first record in **pat. */
        if (*pat)
                **pat = *r_tuple_prev;
        else
                *pat = r_tuple_prev;

        if (ttlp)
                *ttlp = 0;

        /* Explicitly reset both *h_errnop and h_errno to work around
         * https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
        *h_errnop = NETDB_SUCCESS;
        h_errno = 0;

        return NSS_STATUS_SUCCESS;

not_found:
        *h_errnop = HOST_NOT_FOUND;
        return NSS_STATUS_NOTFOUND;
}

static enum nss_status fill_in_hostent(
                const char *canonical, const char *additional,
                int af,
                struct local_address *addresses, unsigned n_addresses,
                uint32_t local_address_ipv4,
                struct hostent *result,
                char *buffer, size_t buflen,
                int *errnop, int *h_errnop,
                int32_t *ttlp,
                char **canonp) {

        size_t l_canonical, l_additional, idx, ms, alen;
        char *r_addr, *r_name, *r_aliases, *r_alias = NULL, *r_addr_list;
        struct local_address *a;
        unsigned n, c;

        assert(canonical);
        assert(result);
        assert(buffer);
        assert(errnop);
        assert(h_errnop);

        PROTECT_ERRNO;

        alen = FAMILY_ADDRESS_SIZE(af);

        for (a = addresses, n = 0, c = 0; n < n_addresses; a++, n++)
                if (af == a->family)
                        c++;

        l_canonical = strlen(canonical);
        l_additional = strlen_ptr(additional);
        ms = ALIGN(l_canonical+1)+
                (additional ? ALIGN(l_additional+1) : 0) +
                sizeof(char*) +
                (additional ? sizeof(char*) : 0) +
                (c > 0 ? c : 1) * ALIGN(alen) +
                (c > 0 ? c+1 : 2) * sizeof(char*);

        if (buflen < ms) {
                UNPROTECT_ERRNO;
                *errnop = ERANGE;
                *h_errnop = NETDB_INTERNAL;
                return NSS_STATUS_TRYAGAIN;
        }

        /* First, fill in hostnames */
        r_name = buffer;
        memcpy(r_name, canonical, l_canonical+1);
        idx = ALIGN(l_canonical+1);

        if (additional) {
                r_alias = buffer + idx;
                memcpy(r_alias, additional, l_additional+1);
                idx += ALIGN(l_additional+1);
        }

        /* Second, create aliases array */
        r_aliases = buffer + idx;
        if (additional) {
                ((char**) r_aliases)[0] = r_alias;
                ((char**) r_aliases)[1] = NULL;
                idx += 2*sizeof(char*);
        } else {
                ((char**) r_aliases)[0] = NULL;
                idx += sizeof(char*);
        }

        /* Third, add addresses */
        r_addr = buffer + idx;
        if (c > 0) {
                unsigned i = 0;

                for (a = addresses, n = 0; n < n_addresses; a++, n++) {
                        if (af != a->family)
                                continue;

                        memcpy(r_addr + i*ALIGN(alen), &a->address, alen);
                        i++;
                }

                assert(i == c);
                idx += c*ALIGN(alen);
        } else {
                if (af == AF_INET)
                        *(uint32_t*) r_addr = local_address_ipv4;
                else
                        memcpy(r_addr, LOCALADDRESS_IPV6, 16);

                idx += ALIGN(alen);
        }

        /* Fourth, add address pointer array */
        r_addr_list = buffer + idx;
        if (c > 0) {
                unsigned i;

                for (i = 0; i < c; i++)
                        ((char**) r_addr_list)[i] = r_addr + i*ALIGN(alen);

                ((char**) r_addr_list)[i] = NULL;
                idx += (c+1) * sizeof(char*);

        } else {
                ((char**) r_addr_list)[0] = r_addr;
                ((char**) r_addr_list)[1] = NULL;
                idx += 2 * sizeof(char*);
        }

        /* Verify the size matches */
        assert(idx == ms);

        result->h_name = r_name;
        result->h_aliases = (char**) r_aliases;
        result->h_addrtype = af;
        result->h_length = alen;
        result->h_addr_list = (char**) r_addr_list;

        if (ttlp)
                *ttlp = 0;

        if (canonp)
                *canonp = r_name;

        /* Explicitly reset both *h_errnop and h_errno to work around
         * https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
        *h_errnop = NETDB_SUCCESS;
        h_errno = 0;

        return NSS_STATUS_SUCCESS;
}

enum nss_status _nss_myhostname_gethostbyname3_r(
                const char *name,
                int af,
                struct hostent *host,
                char *buffer, size_t buflen,
                int *errnop, int *h_errnop,
                int32_t *ttlp,
                char **canonp) {

        _cleanup_free_ struct local_address *addresses = NULL;
        const char *canonical, *additional = NULL;
        _cleanup_free_ char *hn = NULL;
        uint32_t local_address_ipv4 = 0;
        int n_addresses = 0;

        PROTECT_ERRNO;
        BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);

        assert(name);
        assert(host);
        assert(buffer);
        assert(errnop);
        assert(h_errnop);

        if (af == AF_UNSPEC)
                af = AF_INET;

        if (!IN_SET(af, AF_INET, AF_INET6)) {
                UNPROTECT_ERRNO;
                *errnop = EAFNOSUPPORT;
                *h_errnop = NO_DATA;
                return NSS_STATUS_UNAVAIL;
        }

        if (is_localhost(name)) {
                canonical = "localhost";
                local_address_ipv4 = htobe32(INADDR_LOOPBACK);

        } else if (is_gateway_hostname(name)) {

                n_addresses = local_gateways(NULL, 0, af, &addresses);
                if (n_addresses <= 0)
                        goto not_found;

                canonical = "_gateway";

        } else {
                hn = gethostname_malloc();
                if (!hn) {
                        UNPROTECT_ERRNO;
                        *errnop = ENOMEM;
                        *h_errnop = NO_RECOVERY;
                        return NSS_STATUS_TRYAGAIN;
                }

                if (!streq(name, hn) && !streq_ptr(startswith(name, hn), "."))
                        goto not_found;

                n_addresses = local_addresses(NULL, 0, af, &addresses);
                if (n_addresses < 0)
                        n_addresses = 0;

                canonical = hn;
                additional = n_addresses <= 0 && af == AF_INET6 ? "localhost" : NULL;
                local_address_ipv4 = LOCALADDRESS_IPV4;
        }

        UNPROTECT_ERRNO;

        return fill_in_hostent(
                        canonical, additional,
                        af,
                        addresses, n_addresses,
                        local_address_ipv4,
                        host,
                        buffer, buflen,
                        errnop, h_errnop,
                        ttlp,
                        canonp);

not_found:
        *h_errnop = HOST_NOT_FOUND;
        return NSS_STATUS_NOTFOUND;
}

enum nss_status _nss_myhostname_gethostbyaddr2_r(
                const void* addr, socklen_t len,
                int af,
                struct hostent *host,
                char *buffer, size_t buflen,
                int *errnop, int *h_errnop,
                int32_t *ttlp) {

        const char *canonical = NULL, *additional = NULL;
        uint32_t local_address_ipv4 = LOCALADDRESS_IPV4;
        _cleanup_free_ struct local_address *addresses = NULL;
        _cleanup_free_ char *hn = NULL;
        int n_addresses = 0;
        struct local_address *a;
        bool additional_from_hostname = false;
        unsigned n;

        PROTECT_ERRNO;
        BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);

        assert(addr);
        assert(host);
        assert(buffer);
        assert(errnop);
        assert(h_errnop);

        if (!IN_SET(af, AF_INET, AF_INET6)) {
                UNPROTECT_ERRNO;
                *errnop = EAFNOSUPPORT;
                *h_errnop = NO_DATA;
                return NSS_STATUS_UNAVAIL;
        }

        if (len != FAMILY_ADDRESS_SIZE(af)) {
                UNPROTECT_ERRNO;
                *errnop = EINVAL;
                *h_errnop = NO_RECOVERY;
                return NSS_STATUS_UNAVAIL;
        }

        if (af == AF_INET) {
                if ((*(uint32_t*) addr) == LOCALADDRESS_IPV4)
                        goto found;

                if ((*(uint32_t*) addr) == htobe32(INADDR_LOOPBACK)) {
                        canonical = "localhost";
                        local_address_ipv4 = htobe32(INADDR_LOOPBACK);
                        goto found;
                }

        } else {
                assert(af == AF_INET6);

                if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0) {
                        canonical = "localhost";
                        additional_from_hostname = true;
                        goto found;
                }
        }

        n_addresses = local_addresses(NULL, 0, AF_UNSPEC, &addresses);
        for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) {
                if (af != a->family)
                        continue;

                if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0)
                        goto found;
        }

        addresses = mfree(addresses);

        n_addresses = local_gateways(NULL, 0, AF_UNSPEC, &addresses);
        for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) {
                if (af != a->family)
                        continue;

                if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0) {
                        canonical = "_gateway";
                        goto found;
                }
        }

        *h_errnop = HOST_NOT_FOUND;
        return NSS_STATUS_NOTFOUND;

found:
        if (!canonical || additional_from_hostname) {
                hn = gethostname_malloc();
                if (!hn) {
                        UNPROTECT_ERRNO;
                        *errnop = ENOMEM;
                        *h_errnop = NO_RECOVERY;
                        return NSS_STATUS_TRYAGAIN;
                }

                if (!canonical)
                        canonical = hn;
                else
                        additional = hn;
        }

        UNPROTECT_ERRNO;
        return fill_in_hostent(
                        canonical, additional,
                        af,
                        addresses, n_addresses,
                        local_address_ipv4,
                        host,
                        buffer, buflen,
                        errnop, h_errnop,
                        ttlp,
                        NULL);
}

NSS_GETHOSTBYNAME_FALLBACKS(myhostname);
NSS_GETHOSTBYADDR_FALLBACKS(myhostname);
Commit	Line	Data
53e1b683	1	/* SPDX-License-Identifier: LGPL-2.1+ */
6b21f0cf	2
6b21f0cf	3	#include <errno.h>
4e8c8252	4	#include <net/if.h>
07630cea LP	5	#include <netdb.h>
07630cea LP	6	#include <nss.h>
8041b5ba	7	#include <stdlib.h>
8041b5ba	8
b5efdb8a	9	#include "alloc-util.h"
2b2fec7d	10	#include "errno-util.h"
07630cea	11	#include "hostname-util.h"
e80af1bd	12	#include "local-addresses.h"
1c633045	13	#include "macro.h"
c9fdc26e	14	#include "nss-util.h"
0c5eb056	15	#include "signal-util.h"
07630cea	16	#include "string-util.h"
4e8c8252 LP	17
	18	/* We use 127.0.0.2 as IPv4 address. This has the advantage over
	19	* 127.0.0.1 that it can be translated back to the local hostname. For
	20	* IPv6 we use ::1 which unfortunately will not translate back to the
3fdcecc8	21	* hostname but instead something like "localhost" or so. */
4e8c8252	22
8e38570e	23	#define LOCALADDRESS_IPV4 (htobe32(0x7F000002))
4e8c8252	24	#define LOCALADDRESS_IPV6 &in6addr_loopback
4e8c8252	25
c9fdc26e LP	26	NSS_GETHOSTBYNAME_PROTOTYPES(myhostname);
c9fdc26e LP	27	NSS_GETHOSTBYADDR_PROTOTYPES(myhostname);
8041b5ba	28
4e8c8252 LP	29	enum nss_status _nss_myhostname_gethostbyname4_r(
	30	const char *name,
	31	struct gaih_addrtuple **pat,
	32	char *buffer, size_t buflen,
	33	int errnop, int h_errnop,
	34	int32_t *ttlp) {
	35
8041b5ba	36	struct gaih_addrtuple r_tuple, r_tuple_prev = NULL;
e80af1bd	37	_cleanup_free_ struct local_address *addresses = NULL;
5502f0d9 LP	38	_cleanup_free_ char *hn = NULL;
5502f0d9 LP	39	const char *canonical = NULL;
a1077c84	40	int n_addresses = 0;
e8a7a315	41	uint32_t local_address_ipv4;
e80af1bd	42	struct local_address *a;
5502f0d9 LP	43	size_t l, idx, ms;
5502f0d9 LP	44	char *r_name;
e80af1bd	45	unsigned n;
4e8c8252	46
06202b9e	47	PROTECT_ERRNO;
0c5eb056 LP	48	BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
0c5eb056 LP	49
5502f0d9 LP	50	assert(name);
	51	assert(pat);
	52	assert(buffer);
	53	assert(errnop);
	54	assert(h_errnop);
	55
	56	if (is_localhost(name)) {
e8a7a315 LP	57	/* We respond to 'localhost', so that /etc/hosts
e8a7a315 LP	58	* is optional */
4e8c8252	59
e8a7a315	60	canonical = "localhost";
8e38570e	61	local_address_ipv4 = htobe32(INADDR_LOOPBACK);
e9140aff	62
46a5e0e7	63	} else if (is_gateway_hostname(name)) {
e9140aff	64
1d050e1e	65	n_addresses = local_gateways(NULL, 0, AF_UNSPEC, &addresses);
e09e7ac3 LP	66	if (n_addresses <= 0)
e09e7ac3 LP	67	goto not_found;
e9140aff	68
5248e7e1	69	canonical = "_gateway";
e9140aff	70
e8a7a315	71	} else {
5502f0d9 LP	72	hn = gethostname_malloc();
5502f0d9 LP	73	if (!hn) {
cdccd29f	74	UNPROTECT_ERRNO;
0192cbdb	75	*errnop = ENOMEM;
e8a7a315	76	*h_errnop = NO_RECOVERY;
5502f0d9	77	return NSS_STATUS_TRYAGAIN;
e8a7a315 LP	78	}
e8a7a315 LP	79
38b38500	80	/* We respond to our local hostname, our hostname suffixed with a single dot. */
e09e7ac3 LP	81	if (!streq(name, hn) && !streq_ptr(startswith(name, hn), "."))
e09e7ac3 LP	82	goto not_found;
e8a7a315	83
1d050e1e	84	n_addresses = local_addresses(NULL, 0, AF_UNSPEC, &addresses);
e80af1bd LP	85	if (n_addresses < 0)
e80af1bd LP	86	n_addresses = 0;
e8a7a315 LP	87
	88	canonical = hn;
	89	local_address_ipv4 = LOCALADDRESS_IPV4;
	90	}
8041b5ba	91
e8a7a315	92	l = strlen(canonical);
5502f0d9	93	ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * (n_addresses > 0 ? n_addresses : 2);
4e8c8252	94	if (buflen < ms) {
cdccd29f	95	UNPROTECT_ERRNO;
0192cbdb	96	*errnop = ERANGE;
cda458a5	97	*h_errnop = NETDB_INTERNAL;
4e8c8252 LP	98	return NSS_STATUS_TRYAGAIN;
	99	}
	100
	101	/* First, fill in hostname */
	102	r_name = buffer;
e8a7a315	103	memcpy(r_name, canonical, l+1);
4e8c8252 LP	104	idx = ALIGN(l+1);
4e8c8252 LP	105
68a9c7c4 ZJS	106	assert(n_addresses >= 0);
68a9c7c4 ZJS	107	if (n_addresses == 0) {
8041b5ba LP	108	/* Second, fill in IPv6 tuple */
	109	r_tuple = (struct gaih_addrtuple*) (buffer + idx);
	110	r_tuple->next = r_tuple_prev;
	111	r_tuple->name = r_name;
	112	r_tuple->family = AF_INET6;
	113	memcpy(r_tuple->addr, LOCALADDRESS_IPV6, 16);
a1077c84	114	r_tuple->scopeid = 0;
8041b5ba LP	115
	116	idx += ALIGN(sizeof(struct gaih_addrtuple));
	117	r_tuple_prev = r_tuple;
	118
	119	/* Third, fill in IPv4 tuple */
	120	r_tuple = (struct gaih_addrtuple*) (buffer + idx);
	121	r_tuple->next = r_tuple_prev;
	122	r_tuple->name = r_name;
	123	r_tuple->family = AF_INET;
e8a7a315	124	(uint32_t) r_tuple->addr = local_address_ipv4;
a1077c84	125	r_tuple->scopeid = 0;
8041b5ba LP	126
	127	idx += ALIGN(sizeof(struct gaih_addrtuple));
	128	r_tuple_prev = r_tuple;
	129	}
	130
	131	/* Fourth, fill actual addresses in, but in backwards order */
e80af1bd	132	for (a = addresses + n_addresses - 1, n = 0; (int) n < n_addresses; n++, a--) {
8041b5ba LP	133	r_tuple = (struct gaih_addrtuple*) (buffer + idx);
	134	r_tuple->next = r_tuple_prev;
	135	r_tuple->name = r_name;
	136	r_tuple->family = a->family;
a1077c84	137	r_tuple->scopeid = a->family == AF_INET6 && IN6_IS_ADDR_LINKLOCAL(&a->address.in6) ? a->ifindex : 0;
5502f0d9	138	memcpy(r_tuple->addr, &a->address, 16);
8041b5ba LP	139
	140	idx += ALIGN(sizeof(struct gaih_addrtuple));
	141	r_tuple_prev = r_tuple;
	142	}
4e8c8252 LP	143
	144	/* Verify the size matches */
	145	assert(idx == ms);
	146
d2f1f23a ED	147	/* Nscd expects us to store the first record in *pat. /
	148	if (*pat)
	149	*pat = r_tuple_prev;
	150	else
	151	*pat = r_tuple_prev;
4e8c8252 LP	152
	153	if (ttlp)
	154	*ttlp = 0;
	155
06202b9e YW	156	/* Explicitly reset both *h_errnop and h_errno to work around
06202b9e YW	157	* https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
e70df46b LP	158	*h_errnop = NETDB_SUCCESS;
	159	h_errno = 0;
	160
4e8c8252	161	return NSS_STATUS_SUCCESS;
e09e7ac3 LP	162
	163	not_found:
	164	*h_errnop = HOST_NOT_FOUND;
	165	return NSS_STATUS_NOTFOUND;
4e8c8252	166	}
6b21f0cf LP	167
6b21f0cf LP	168	static enum nss_status fill_in_hostent(
e8a7a315	169	const char canonical, const char additional,
4e8c8252	170	int af,
e80af1bd	171	struct local_address *addresses, unsigned n_addresses,
e8a7a315	172	uint32_t local_address_ipv4,
4e8c8252 LP	173	struct hostent *result,
4e8c8252 LP	174	char *buffer, size_t buflen,
0192cbdb	175	int errnop, int h_errnop,
4e8c8252 LP	176	int32_t *ttlp,
	177	char **canonp) {
	178
d4c9895d	179	size_t l_canonical, l_additional, idx, ms, alen;
e8a7a315	180	char r_addr, r_name, r_aliases, r_alias = NULL, *r_addr_list;
e80af1bd	181	struct local_address *a;
e8a7a315	182	unsigned n, c;
8041b5ba	183
5502f0d9 LP	184	assert(canonical);
	185	assert(result);
	186	assert(buffer);
	187	assert(errnop);
	188	assert(h_errnop);
	189
cdccd29f LP	190	PROTECT_ERRNO;
cdccd29f LP	191
9d485985	192	alen = FAMILY_ADDRESS_SIZE(af);
8041b5ba	193
8041b5ba LP	194	for (a = addresses, n = 0, c = 0; n < n_addresses; a++, n++)
	195	if (af == a->family)
	196	c++;
4e8c8252	197
e8a7a315	198	l_canonical = strlen(canonical);
7bf7ce28	199	l_additional = strlen_ptr(additional);
e8a7a315 LP	200	ms = ALIGN(l_canonical+1)+
e8a7a315 LP	201	(additional ? ALIGN(l_additional+1) : 0) +
5502f0d9	202	sizeof(char*) +
e8a7a315	203	(additional ? sizeof(char*) : 0) +
d4c9895d	204	(c > 0 ? c : 1) * ALIGN(alen) +
5502f0d9	205	(c > 0 ? c+1 : 2) * sizeof(char*);
8041b5ba	206
4e8c8252	207	if (buflen < ms) {
cdccd29f	208	UNPROTECT_ERRNO;
0192cbdb	209	*errnop = ERANGE;
cda458a5	210	*h_errnop = NETDB_INTERNAL;
4e8c8252 LP	211	return NSS_STATUS_TRYAGAIN;
	212	}
	213
e8a7a315	214	/* First, fill in hostnames */
4e8c8252	215	r_name = buffer;
e8a7a315 LP	216	memcpy(r_name, canonical, l_canonical+1);
e8a7a315 LP	217	idx = ALIGN(l_canonical+1);
4e8c8252	218
e8a7a315 LP	219	if (additional) {
	220	r_alias = buffer + idx;
	221	memcpy(r_alias, additional, l_additional+1);
	222	idx += ALIGN(l_additional+1);
	223	}
	224
	225	/* Second, create aliases array */
4e8c8252	226	r_aliases = buffer + idx;
e8a7a315 LP	227	if (additional) {
	228	((char**) r_aliases)[0] = r_alias;
	229	((char**) r_aliases)[1] = NULL;
	230	idx += 2sizeof(char);
	231	} else {
	232	((char**) r_aliases)[0] = NULL;
	233	idx += sizeof(char*);
	234	}
4e8c8252	235
8041b5ba	236	/* Third, add addresses */
4e8c8252	237	r_addr = buffer + idx;
8041b5ba LP	238	if (c > 0) {
	239	unsigned i = 0;
	240
	241	for (a = addresses, n = 0; n < n_addresses; a++, n++) {
	242	if (af != a->family)
	243	continue;
	244
5502f0d9	245	memcpy(r_addr + i*ALIGN(alen), &a->address, alen);
8041b5ba LP	246	i++;
	247	}
	248
	249	assert(i == c);
	250	idx += c*ALIGN(alen);
	251	} else {
	252	if (af == AF_INET)
e8a7a315	253	(uint32_t) r_addr = local_address_ipv4;
8041b5ba LP	254	else
	255	memcpy(r_addr, LOCALADDRESS_IPV6, 16);
	256
	257	idx += ALIGN(alen);
	258	}
4e8c8252 LP	259
	260	/* Fourth, add address pointer array */
	261	r_addr_list = buffer + idx;
8041b5ba	262	if (c > 0) {
d4c9895d	263	unsigned i;
8041b5ba	264
d4c9895d LP	265	for (i = 0; i < c; i++)
d4c9895d LP	266	((char*) r_addr_list)[i] = r_addr + iALIGN(alen);
8041b5ba	267
d4c9895d LP	268	((char**) r_addr_list)[i] = NULL;
d4c9895d LP	269	idx += (c+1) * sizeof(char*);
8041b5ba LP	270
	271	} else {
	272	((char**) r_addr_list)[0] = r_addr;
	273	((char**) r_addr_list)[1] = NULL;
d4c9895d	274	idx += 2 * sizeof(char*);
8041b5ba	275	}
4e8c8252 LP	276
	277	/* Verify the size matches */
	278	assert(idx == ms);
	279
	280	result->h_name = r_name;
	281	result->h_aliases = (char**) r_aliases;
	282	result->h_addrtype = af;
	283	result->h_length = alen;
	284	result->h_addr_list = (char**) r_addr_list;
	285
	286	if (ttlp)
	287	*ttlp = 0;
	288
	289	if (canonp)
	290	*canonp = r_name;
	291
06202b9e YW	292	/* Explicitly reset both *h_errnop and h_errno to work around
06202b9e YW	293	* https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
e70df46b LP	294	*h_errnop = NETDB_SUCCESS;
	295	h_errno = 0;
	296
4e8c8252	297	return NSS_STATUS_SUCCESS;
6b21f0cf LP	298	}
6b21f0cf LP	299
4e8c8252 LP	300	enum nss_status _nss_myhostname_gethostbyname3_r(
	301	const char *name,
	302	int af,
	303	struct hostent *host,
	304	char *buffer, size_t buflen,
	305	int errnop, int h_errnop,
	306	int32_t *ttlp,
	307	char **canonp) {
6b21f0cf	308
e80af1bd	309	_cleanup_free_ struct local_address *addresses = NULL;
e8a7a315	310	const char canonical, additional = NULL;
5502f0d9	311	_cleanup_free_ char *hn = NULL;
e9140aff	312	uint32_t local_address_ipv4 = 0;
e80af1bd	313	int n_addresses = 0;
5502f0d9	314
06202b9e	315	PROTECT_ERRNO;
0c5eb056 LP	316	BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
0c5eb056 LP	317
5502f0d9 LP	318	assert(name);
	319	assert(host);
	320	assert(buffer);
	321	assert(errnop);
	322	assert(h_errnop);
6b21f0cf	323
4e8c8252 LP	324	if (af == AF_UNSPEC)
4e8c8252 LP	325	af = AF_INET;
6b21f0cf	326
ec2ce0c5	327	if (!IN_SET(af, AF_INET, AF_INET6)) {
cdccd29f	328	UNPROTECT_ERRNO;
0192cbdb	329	*errnop = EAFNOSUPPORT;
4e8c8252 LP	330	*h_errnop = NO_DATA;
	331	return NSS_STATUS_UNAVAIL;
	332	}
6b21f0cf	333
5502f0d9	334	if (is_localhost(name)) {
e8a7a315	335	canonical = "localhost";
8e38570e	336	local_address_ipv4 = htobe32(INADDR_LOOPBACK);
e9140aff	337
46a5e0e7	338	} else if (is_gateway_hostname(name)) {
e9140aff	339
1d050e1e	340	n_addresses = local_gateways(NULL, 0, af, &addresses);
e09e7ac3 LP	341	if (n_addresses <= 0)
e09e7ac3 LP	342	goto not_found;
e9140aff	343
5248e7e1	344	canonical = "_gateway";
e9140aff	345
e8a7a315	346	} else {
5502f0d9 LP	347	hn = gethostname_malloc();
5502f0d9 LP	348	if (!hn) {
cdccd29f	349	UNPROTECT_ERRNO;
0192cbdb	350	*errnop = ENOMEM;
e8a7a315	351	*h_errnop = NO_RECOVERY;
5502f0d9	352	return NSS_STATUS_TRYAGAIN;
e8a7a315	353	}
6b21f0cf	354
e09e7ac3 LP	355	if (!streq(name, hn) && !streq_ptr(startswith(name, hn), "."))
e09e7ac3 LP	356	goto not_found;
e8a7a315	357
1d050e1e	358	n_addresses = local_addresses(NULL, 0, af, &addresses);
e80af1bd LP	359	if (n_addresses < 0)
e80af1bd LP	360	n_addresses = 0;
e8a7a315 LP	361
	362	canonical = hn;
	363	additional = n_addresses <= 0 && af == AF_INET6 ? "localhost" : NULL;
	364	local_address_ipv4 = LOCALADDRESS_IPV4;
4e8c8252	365	}
6b21f0cf	366
cdccd29f LP	367	UNPROTECT_ERRNO;
cdccd29f LP	368
e8a7a315 LP	369	return fill_in_hostent(
	370	canonical, additional,
	371	af,
	372	addresses, n_addresses,
	373	local_address_ipv4,
	374	host,
	375	buffer, buflen,
0192cbdb	376	errnop, h_errnop,
e8a7a315 LP	377	ttlp,
e8a7a315 LP	378	canonp);
e09e7ac3 LP	379
	380	not_found:
	381	*h_errnop = HOST_NOT_FOUND;
	382	return NSS_STATUS_NOTFOUND;
4e8c8252	383	}
6b21f0cf	384
4e8c8252 LP	385	enum nss_status _nss_myhostname_gethostbyaddr2_r(
	386	const void* addr, socklen_t len,
	387	int af,
	388	struct hostent *host,
	389	char *buffer, size_t buflen,
	390	int errnop, int h_errnop,
	391	int32_t *ttlp) {
6b21f0cf	392
e8a7a315	393	const char canonical = NULL, additional = NULL;
5502f0d9	394	uint32_t local_address_ipv4 = LOCALADDRESS_IPV4;
e80af1bd	395	_cleanup_free_ struct local_address *addresses = NULL;
5502f0d9	396	_cleanup_free_ char *hn = NULL;
e80af1bd LP	397	int n_addresses = 0;
e80af1bd LP	398	struct local_address *a;
3fdcecc8	399	bool additional_from_hostname = false;
e80af1bd	400	unsigned n;
5502f0d9	401
06202b9e	402	PROTECT_ERRNO;
0c5eb056 LP	403	BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
0c5eb056 LP	404
5502f0d9 LP	405	assert(addr);
	406	assert(host);
	407	assert(buffer);
	408	assert(errnop);
	409	assert(h_errnop);
8041b5ba	410
555bd6e9	411	if (!IN_SET(af, AF_INET, AF_INET6)) {
cdccd29f	412	UNPROTECT_ERRNO;
0192cbdb	413	*errnop = EAFNOSUPPORT;
555bd6e9 LP	414	*h_errnop = NO_DATA;
	415	return NSS_STATUS_UNAVAIL;
	416	}
	417
9d485985	418	if (len != FAMILY_ADDRESS_SIZE(af)) {
cdccd29f	419	UNPROTECT_ERRNO;
0192cbdb	420	*errnop = EINVAL;
8041b5ba LP	421	*h_errnop = NO_RECOVERY;
	422	return NSS_STATUS_UNAVAIL;
	423	}
6b21f0cf	424
4e8c8252	425	if (af == AF_INET) {
8041b5ba LP	426	if (((uint32_t) addr) == LOCALADDRESS_IPV4)
8041b5ba LP	427	goto found;
6b21f0cf	428
8e38570e	429	if (((uint32_t) addr) == htobe32(INADDR_LOOPBACK)) {
e8a7a315	430	canonical = "localhost";
8e38570e	431	local_address_ipv4 = htobe32(INADDR_LOOPBACK);
e8a7a315 LP	432	goto found;
	433	}
	434
555bd6e9 LP	435	} else {
555bd6e9 LP	436	assert(af == AF_INET6);
8041b5ba	437
e8a7a315	438	if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0) {
3fdcecc8 LP	439	canonical = "localhost";
3fdcecc8 LP	440	additional_from_hostname = true;
8041b5ba	441	goto found;
e8a7a315	442	}
4e8c8252 LP	443	}
4e8c8252 LP	444
1d050e1e	445	n_addresses = local_addresses(NULL, 0, AF_UNSPEC, &addresses);
68a9c7c4 ZJS	446	for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) {
	447	if (af != a->family)
	448	continue;
8041b5ba	449
68a9c7c4 ZJS	450	if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0)
68a9c7c4 ZJS	451	goto found;
e9140aff LP	452	}
e9140aff LP	453
97b11eed	454	addresses = mfree(addresses);
e9140aff	455
1d050e1e	456	n_addresses = local_gateways(NULL, 0, AF_UNSPEC, &addresses);
68a9c7c4 ZJS	457	for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) {
	458	if (af != a->family)
	459	continue;
e9140aff	460
68a9c7c4	461	if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0) {
5248e7e1	462	canonical = "_gateway";
68a9c7c4	463	goto found;
e9140aff	464	}
8041b5ba LP	465	}
8041b5ba LP	466
8041b5ba	467	*h_errnop = HOST_NOT_FOUND;
8041b5ba LP	468	return NSS_STATUS_NOTFOUND;
	469
	470	found:
82e4c2d6	471	if (!canonical \|\| additional_from_hostname) {
3fdcecc8 LP	472	hn = gethostname_malloc();
3fdcecc8 LP	473	if (!hn) {
cdccd29f	474	UNPROTECT_ERRNO;
0192cbdb	475	*errnop = ENOMEM;
3fdcecc8 LP	476	*h_errnop = NO_RECOVERY;
	477	return NSS_STATUS_TRYAGAIN;
	478	}
	479
	480	if (!canonical)
	481	canonical = hn;
82e4c2d6	482	else
3fdcecc8 LP	483	additional = hn;
3fdcecc8 LP	484	}
4e8c8252	485
cdccd29f	486	UNPROTECT_ERRNO;
e8a7a315 LP	487	return fill_in_hostent(
	488	canonical, additional,
	489	af,
	490	addresses, n_addresses,
	491	local_address_ipv4,
	492	host,
	493	buffer, buflen,
0192cbdb	494	errnop, h_errnop,
e8a7a315 LP	495	ttlp,
e8a7a315 LP	496	NULL);
4e8c8252	497	}
6b21f0cf	498
c9fdc26e LP	499	NSS_GETHOSTBYNAME_FALLBACKS(myhostname);
c9fdc26e LP	500	NSS_GETHOSTBYADDR_FALLBACKS(myhostname);