[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 <string.h>

#include "alloc-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"
#include "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) {
                        *h_errnop = HOST_NOT_FOUND;
                        return NSS_STATUS_NOTFOUND;
                }

                canonical = "_gateway";

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

                /* We respond to our local host name, our hostname suffixed with a single dot. */
                if (!streq(name, hn) && !streq_ptr(startswith(name, hn), ".")) {
                        *h_errnop = HOST_NOT_FOUND;
                        return NSS_STATUS_NOTFOUND;
                }

                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) {
                *errnop = DISARM_PROTECT_ERRNO(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;
}

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, int* _saved_errno_p,
                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);
        assert(_saved_errno_p);

        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) {
                *errnop = DISARM_PROTECT_ERRNO_INNER(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)) {
                *errnop = DISARM_PROTECT_ERRNO(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) {
                        *h_errnop = HOST_NOT_FOUND;
                        return NSS_STATUS_NOTFOUND;
                }

                canonical = "_gateway";

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

                if (!streq(name, hn) && !streq_ptr(startswith(name, hn), ".")) {
                        *h_errnop = HOST_NOT_FOUND;
                        return NSS_STATUS_NOTFOUND;
                }

                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;
        }

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

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)) {
                *errnop = DISARM_PROTECT_ERRNO(EAFNOSUPPORT);
                *h_errnop = NO_DATA;
                return NSS_STATUS_UNAVAIL;
        }

        if (len != FAMILY_ADDRESS_SIZE(af)) {
                *errnop = DISARM_PROTECT_ERRNO(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) {
                        *errnop = DISARM_PROTECT_ERRNO(ENOMEM);
                        *h_errnop = NO_RECOVERY;
                        return NSS_STATUS_TRYAGAIN;
                }

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

        return fill_in_hostent(
                        canonical, additional,
                        af,
                        addresses, n_addresses,
                        local_address_ipv4,
                        host,
                        buffer, buflen,
                        errnop, h_errnop, &_saved_errno_,
                        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>
07630cea	8	#include <string.h>
8041b5ba	9
b5efdb8a	10	#include "alloc-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"
c9fdc26e	17	#include "util.h"
4e8c8252 LP	18
	19	/* We use 127.0.0.2 as IPv4 address. This has the advantage over
	20	* 127.0.0.1 that it can be translated back to the local hostname. For
	21	* IPv6 we use ::1 which unfortunately will not translate back to the
3fdcecc8	22	* hostname but instead something like "localhost" or so. */
4e8c8252	23
8e38570e	24	#define LOCALADDRESS_IPV4 (htobe32(0x7F000002))
4e8c8252	25	#define LOCALADDRESS_IPV6 &in6addr_loopback
4e8c8252	26
c9fdc26e LP	27	NSS_GETHOSTBYNAME_PROTOTYPES(myhostname);
c9fdc26e LP	28	NSS_GETHOSTBYADDR_PROTOTYPES(myhostname);
8041b5ba	29
4e8c8252 LP	30	enum nss_status _nss_myhostname_gethostbyname4_r(
	31	const char *name,
	32	struct gaih_addrtuple **pat,
	33	char *buffer, size_t buflen,
	34	int errnop, int h_errnop,
	35	int32_t *ttlp) {
	36
8041b5ba	37	struct gaih_addrtuple r_tuple, r_tuple_prev = NULL;
e80af1bd	38	_cleanup_free_ struct local_address *addresses = NULL;
5502f0d9 LP	39	_cleanup_free_ char *hn = NULL;
5502f0d9 LP	40	const char *canonical = NULL;
a1077c84	41	int n_addresses = 0;
e8a7a315	42	uint32_t local_address_ipv4;
e80af1bd	43	struct local_address *a;
5502f0d9 LP	44	size_t l, idx, ms;
5502f0d9 LP	45	char *r_name;
e80af1bd	46	unsigned n;
4e8c8252	47
06202b9e	48	PROTECT_ERRNO;
0c5eb056 LP	49	BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
0c5eb056 LP	50
5502f0d9 LP	51	assert(name);
	52	assert(pat);
	53	assert(buffer);
	54	assert(errnop);
	55	assert(h_errnop);
	56
	57	if (is_localhost(name)) {
e8a7a315 LP	58	/* We respond to 'localhost', so that /etc/hosts
e8a7a315 LP	59	* is optional */
4e8c8252	60
e8a7a315	61	canonical = "localhost";
8e38570e	62	local_address_ipv4 = htobe32(INADDR_LOOPBACK);
e9140aff	63
46a5e0e7	64	} else if (is_gateway_hostname(name)) {
e9140aff	65
1d050e1e	66	n_addresses = local_gateways(NULL, 0, AF_UNSPEC, &addresses);
e9140aff	67	if (n_addresses <= 0) {
e9140aff LP	68	*h_errnop = HOST_NOT_FOUND;
	69	return NSS_STATUS_NOTFOUND;
	70	}
	71
5248e7e1	72	canonical = "_gateway";
e9140aff	73
e8a7a315	74	} else {
5502f0d9 LP	75	hn = gethostname_malloc();
5502f0d9 LP	76	if (!hn) {
b26c9041	77	*errnop = DISARM_PROTECT_ERRNO(ENOMEM);
e8a7a315	78	*h_errnop = NO_RECOVERY;
5502f0d9	79	return NSS_STATUS_TRYAGAIN;
e8a7a315 LP	80	}
e8a7a315 LP	81
61233823	82	/* We respond to our local host name, our hostname suffixed with a single dot. */
5502f0d9	83	if (!streq(name, hn) && !streq_ptr(startswith(name, hn), ".")) {
e8a7a315 LP	84	*h_errnop = HOST_NOT_FOUND;
	85	return NSS_STATUS_NOTFOUND;
	86	}
	87
1d050e1e	88	n_addresses = local_addresses(NULL, 0, AF_UNSPEC, &addresses);
e80af1bd LP	89	if (n_addresses < 0)
e80af1bd LP	90	n_addresses = 0;
e8a7a315 LP	91
	92	canonical = hn;
	93	local_address_ipv4 = LOCALADDRESS_IPV4;
	94	}
8041b5ba	95
e8a7a315	96	l = strlen(canonical);
5502f0d9	97	ms = ALIGN(l+1) + ALIGN(sizeof(struct gaih_addrtuple)) * (n_addresses > 0 ? n_addresses : 2);
4e8c8252	98	if (buflen < ms) {
b26c9041	99	*errnop = DISARM_PROTECT_ERRNO(ERANGE);
cda458a5	100	*h_errnop = NETDB_INTERNAL;
4e8c8252 LP	101	return NSS_STATUS_TRYAGAIN;
	102	}
	103
	104	/* First, fill in hostname */
	105	r_name = buffer;
e8a7a315	106	memcpy(r_name, canonical, l+1);
4e8c8252 LP	107	idx = ALIGN(l+1);
4e8c8252 LP	108
68a9c7c4 ZJS	109	assert(n_addresses >= 0);
68a9c7c4 ZJS	110	if (n_addresses == 0) {
8041b5ba LP	111	/* Second, fill in IPv6 tuple */
	112	r_tuple = (struct gaih_addrtuple*) (buffer + idx);
	113	r_tuple->next = r_tuple_prev;
	114	r_tuple->name = r_name;
	115	r_tuple->family = AF_INET6;
	116	memcpy(r_tuple->addr, LOCALADDRESS_IPV6, 16);
a1077c84	117	r_tuple->scopeid = 0;
8041b5ba LP	118
	119	idx += ALIGN(sizeof(struct gaih_addrtuple));
	120	r_tuple_prev = r_tuple;
	121
	122	/* Third, fill in IPv4 tuple */
	123	r_tuple = (struct gaih_addrtuple*) (buffer + idx);
	124	r_tuple->next = r_tuple_prev;
	125	r_tuple->name = r_name;
	126	r_tuple->family = AF_INET;
e8a7a315	127	(uint32_t) r_tuple->addr = local_address_ipv4;
a1077c84	128	r_tuple->scopeid = 0;
8041b5ba LP	129
	130	idx += ALIGN(sizeof(struct gaih_addrtuple));
	131	r_tuple_prev = r_tuple;
	132	}
	133
	134	/* Fourth, fill actual addresses in, but in backwards order */
e80af1bd	135	for (a = addresses + n_addresses - 1, n = 0; (int) n < n_addresses; n++, a--) {
8041b5ba LP	136	r_tuple = (struct gaih_addrtuple*) (buffer + idx);
	137	r_tuple->next = r_tuple_prev;
	138	r_tuple->name = r_name;
	139	r_tuple->family = a->family;
a1077c84	140	r_tuple->scopeid = a->family == AF_INET6 && IN6_IS_ADDR_LINKLOCAL(&a->address.in6) ? a->ifindex : 0;
5502f0d9	141	memcpy(r_tuple->addr, &a->address, 16);
8041b5ba LP	142
	143	idx += ALIGN(sizeof(struct gaih_addrtuple));
	144	r_tuple_prev = r_tuple;
	145	}
4e8c8252 LP	146
	147	/* Verify the size matches */
	148	assert(idx == ms);
	149
d2f1f23a ED	150	/* Nscd expects us to store the first record in *pat. /
	151	if (*pat)
	152	*pat = r_tuple_prev;
	153	else
	154	*pat = r_tuple_prev;
4e8c8252 LP	155
	156	if (ttlp)
	157	*ttlp = 0;
	158
06202b9e YW	159	/* Explicitly reset both *h_errnop and h_errno to work around
06202b9e YW	160	* https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
e70df46b LP	161	*h_errnop = NETDB_SUCCESS;
	162	h_errno = 0;
	163
4e8c8252 LP	164	return NSS_STATUS_SUCCESS;
4e8c8252 LP	165	}
6b21f0cf LP	166
6b21f0cf LP	167	static enum nss_status fill_in_hostent(
e8a7a315	168	const char canonical, const char additional,
4e8c8252	169	int af,
e80af1bd	170	struct local_address *addresses, unsigned n_addresses,
e8a7a315	171	uint32_t local_address_ipv4,
4e8c8252 LP	172	struct hostent *result,
4e8c8252 LP	173	char *buffer, size_t buflen,
b26c9041	174	int errnop, int h_errnop, int* _saved_errno_p,
4e8c8252 LP	175	int32_t *ttlp,
	176	char **canonp) {
	177
d4c9895d	178	size_t l_canonical, l_additional, idx, ms, alen;
e8a7a315	179	char r_addr, r_name, r_aliases, r_alias = NULL, *r_addr_list;
e80af1bd	180	struct local_address *a;
e8a7a315	181	unsigned n, c;
8041b5ba	182
5502f0d9 LP	183	assert(canonical);
	184	assert(result);
	185	assert(buffer);
	186	assert(errnop);
	187	assert(h_errnop);
b26c9041	188	assert(_saved_errno_p);
5502f0d9	189
9d485985	190	alen = FAMILY_ADDRESS_SIZE(af);
8041b5ba	191
8041b5ba LP	192	for (a = addresses, n = 0, c = 0; n < n_addresses; a++, n++)
	193	if (af == a->family)
	194	c++;
4e8c8252	195
e8a7a315	196	l_canonical = strlen(canonical);
7bf7ce28	197	l_additional = strlen_ptr(additional);
e8a7a315 LP	198	ms = ALIGN(l_canonical+1)+
e8a7a315 LP	199	(additional ? ALIGN(l_additional+1) : 0) +
5502f0d9	200	sizeof(char*) +
e8a7a315	201	(additional ? sizeof(char*) : 0) +
d4c9895d	202	(c > 0 ? c : 1) * ALIGN(alen) +
5502f0d9	203	(c > 0 ? c+1 : 2) * sizeof(char*);
8041b5ba	204
4e8c8252	205	if (buflen < ms) {
b26c9041	206	*errnop = DISARM_PROTECT_ERRNO_INNER(ERANGE);
cda458a5	207	*h_errnop = NETDB_INTERNAL;
4e8c8252 LP	208	return NSS_STATUS_TRYAGAIN;
	209	}
	210
e8a7a315	211	/* First, fill in hostnames */
4e8c8252	212	r_name = buffer;
e8a7a315 LP	213	memcpy(r_name, canonical, l_canonical+1);
e8a7a315 LP	214	idx = ALIGN(l_canonical+1);
4e8c8252	215
e8a7a315 LP	216	if (additional) {
	217	r_alias = buffer + idx;
	218	memcpy(r_alias, additional, l_additional+1);
	219	idx += ALIGN(l_additional+1);
	220	}
	221
	222	/* Second, create aliases array */
4e8c8252	223	r_aliases = buffer + idx;
e8a7a315 LP	224	if (additional) {
	225	((char**) r_aliases)[0] = r_alias;
	226	((char**) r_aliases)[1] = NULL;
	227	idx += 2sizeof(char);
	228	} else {
	229	((char**) r_aliases)[0] = NULL;
	230	idx += sizeof(char*);
	231	}
4e8c8252	232
8041b5ba	233	/* Third, add addresses */
4e8c8252	234	r_addr = buffer + idx;
8041b5ba LP	235	if (c > 0) {
	236	unsigned i = 0;
	237
	238	for (a = addresses, n = 0; n < n_addresses; a++, n++) {
	239	if (af != a->family)
	240	continue;
	241
5502f0d9	242	memcpy(r_addr + i*ALIGN(alen), &a->address, alen);
8041b5ba LP	243	i++;
	244	}
	245
	246	assert(i == c);
	247	idx += c*ALIGN(alen);
	248	} else {
	249	if (af == AF_INET)
e8a7a315	250	(uint32_t) r_addr = local_address_ipv4;
8041b5ba LP	251	else
	252	memcpy(r_addr, LOCALADDRESS_IPV6, 16);
	253
	254	idx += ALIGN(alen);
	255	}
4e8c8252 LP	256
	257	/* Fourth, add address pointer array */
	258	r_addr_list = buffer + idx;
8041b5ba	259	if (c > 0) {
d4c9895d	260	unsigned i;
8041b5ba	261
d4c9895d LP	262	for (i = 0; i < c; i++)
d4c9895d LP	263	((char*) r_addr_list)[i] = r_addr + iALIGN(alen);
8041b5ba	264
d4c9895d LP	265	((char**) r_addr_list)[i] = NULL;
d4c9895d LP	266	idx += (c+1) * sizeof(char*);
8041b5ba LP	267
	268	} else {
	269	((char**) r_addr_list)[0] = r_addr;
	270	((char**) r_addr_list)[1] = NULL;
d4c9895d	271	idx += 2 * sizeof(char*);
8041b5ba	272	}
4e8c8252 LP	273
	274	/* Verify the size matches */
	275	assert(idx == ms);
	276
	277	result->h_name = r_name;
	278	result->h_aliases = (char**) r_aliases;
	279	result->h_addrtype = af;
	280	result->h_length = alen;
	281	result->h_addr_list = (char**) r_addr_list;
	282
	283	if (ttlp)
	284	*ttlp = 0;
	285
	286	if (canonp)
	287	*canonp = r_name;
	288
06202b9e YW	289	/* Explicitly reset both *h_errnop and h_errno to work around
06202b9e YW	290	* https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
e70df46b LP	291	*h_errnop = NETDB_SUCCESS;
	292	h_errno = 0;
	293
4e8c8252	294	return NSS_STATUS_SUCCESS;
6b21f0cf LP	295	}
6b21f0cf LP	296
4e8c8252 LP	297	enum nss_status _nss_myhostname_gethostbyname3_r(
	298	const char *name,
	299	int af,
	300	struct hostent *host,
	301	char *buffer, size_t buflen,
	302	int errnop, int h_errnop,
	303	int32_t *ttlp,
	304	char **canonp) {
6b21f0cf	305
e80af1bd	306	_cleanup_free_ struct local_address *addresses = NULL;
e8a7a315	307	const char canonical, additional = NULL;
5502f0d9	308	_cleanup_free_ char *hn = NULL;
e9140aff	309	uint32_t local_address_ipv4 = 0;
e80af1bd	310	int n_addresses = 0;
5502f0d9	311
06202b9e	312	PROTECT_ERRNO;
0c5eb056 LP	313	BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
0c5eb056 LP	314
5502f0d9 LP	315	assert(name);
	316	assert(host);
	317	assert(buffer);
	318	assert(errnop);
	319	assert(h_errnop);
6b21f0cf	320
4e8c8252 LP	321	if (af == AF_UNSPEC)
4e8c8252 LP	322	af = AF_INET;
6b21f0cf	323
ec2ce0c5	324	if (!IN_SET(af, AF_INET, AF_INET6)) {
b26c9041	325	*errnop = DISARM_PROTECT_ERRNO(EAFNOSUPPORT);
4e8c8252 LP	326	*h_errnop = NO_DATA;
	327	return NSS_STATUS_UNAVAIL;
	328	}
6b21f0cf	329
5502f0d9	330	if (is_localhost(name)) {
e8a7a315	331	canonical = "localhost";
8e38570e	332	local_address_ipv4 = htobe32(INADDR_LOOPBACK);
e9140aff	333
46a5e0e7	334	} else if (is_gateway_hostname(name)) {
e9140aff	335
1d050e1e	336	n_addresses = local_gateways(NULL, 0, af, &addresses);
e9140aff	337	if (n_addresses <= 0) {
e9140aff LP	338	*h_errnop = HOST_NOT_FOUND;
	339	return NSS_STATUS_NOTFOUND;
	340	}
	341
5248e7e1	342	canonical = "_gateway";
e9140aff	343
e8a7a315	344	} else {
5502f0d9 LP	345	hn = gethostname_malloc();
5502f0d9 LP	346	if (!hn) {
b26c9041	347	*errnop = DISARM_PROTECT_ERRNO(ENOMEM);
e8a7a315	348	*h_errnop = NO_RECOVERY;
5502f0d9	349	return NSS_STATUS_TRYAGAIN;
e8a7a315	350	}
6b21f0cf	351
5502f0d9	352	if (!streq(name, hn) && !streq_ptr(startswith(name, hn), ".")) {
e8a7a315 LP	353	*h_errnop = HOST_NOT_FOUND;
	354	return NSS_STATUS_NOTFOUND;
	355	}
	356
1d050e1e	357	n_addresses = local_addresses(NULL, 0, af, &addresses);
e80af1bd LP	358	if (n_addresses < 0)
e80af1bd LP	359	n_addresses = 0;
e8a7a315 LP	360
	361	canonical = hn;
	362	additional = n_addresses <= 0 && af == AF_INET6 ? "localhost" : NULL;
	363	local_address_ipv4 = LOCALADDRESS_IPV4;
4e8c8252	364	}
6b21f0cf	365
e8a7a315 LP	366	return fill_in_hostent(
	367	canonical, additional,
	368	af,
	369	addresses, n_addresses,
	370	local_address_ipv4,
	371	host,
	372	buffer, buflen,
b26c9041	373	errnop, h_errnop, &_saved_errno_,
e8a7a315 LP	374	ttlp,
e8a7a315 LP	375	canonp);
4e8c8252	376	}
6b21f0cf	377
4e8c8252 LP	378	enum nss_status _nss_myhostname_gethostbyaddr2_r(
	379	const void* addr, socklen_t len,
	380	int af,
	381	struct hostent *host,
	382	char *buffer, size_t buflen,
	383	int errnop, int h_errnop,
	384	int32_t *ttlp) {
6b21f0cf	385
e8a7a315	386	const char canonical = NULL, additional = NULL;
5502f0d9	387	uint32_t local_address_ipv4 = LOCALADDRESS_IPV4;
e80af1bd	388	_cleanup_free_ struct local_address *addresses = NULL;
5502f0d9	389	_cleanup_free_ char *hn = NULL;
e80af1bd LP	390	int n_addresses = 0;
e80af1bd LP	391	struct local_address *a;
3fdcecc8	392	bool additional_from_hostname = false;
e80af1bd	393	unsigned n;
5502f0d9	394
06202b9e	395	PROTECT_ERRNO;
0c5eb056 LP	396	BLOCK_SIGNALS(NSS_SIGNALS_BLOCK);
0c5eb056 LP	397
5502f0d9 LP	398	assert(addr);
	399	assert(host);
	400	assert(buffer);
	401	assert(errnop);
	402	assert(h_errnop);
8041b5ba	403
555bd6e9	404	if (!IN_SET(af, AF_INET, AF_INET6)) {
b26c9041	405	*errnop = DISARM_PROTECT_ERRNO(EAFNOSUPPORT);
555bd6e9 LP	406	*h_errnop = NO_DATA;
	407	return NSS_STATUS_UNAVAIL;
	408	}
	409
9d485985	410	if (len != FAMILY_ADDRESS_SIZE(af)) {
b26c9041	411	*errnop = DISARM_PROTECT_ERRNO(EINVAL);
8041b5ba LP	412	*h_errnop = NO_RECOVERY;
	413	return NSS_STATUS_UNAVAIL;
	414	}
6b21f0cf	415
4e8c8252	416	if (af == AF_INET) {
8041b5ba LP	417	if (((uint32_t) addr) == LOCALADDRESS_IPV4)
8041b5ba LP	418	goto found;
6b21f0cf	419
8e38570e	420	if (((uint32_t) addr) == htobe32(INADDR_LOOPBACK)) {
e8a7a315	421	canonical = "localhost";
8e38570e	422	local_address_ipv4 = htobe32(INADDR_LOOPBACK);
e8a7a315 LP	423	goto found;
	424	}
	425
555bd6e9 LP	426	} else {
555bd6e9 LP	427	assert(af == AF_INET6);
8041b5ba	428
e8a7a315	429	if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0) {
3fdcecc8 LP	430	canonical = "localhost";
3fdcecc8 LP	431	additional_from_hostname = true;
8041b5ba	432	goto found;
e8a7a315	433	}
4e8c8252 LP	434	}
4e8c8252 LP	435
1d050e1e	436	n_addresses = local_addresses(NULL, 0, AF_UNSPEC, &addresses);
68a9c7c4 ZJS	437	for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) {
	438	if (af != a->family)
	439	continue;
8041b5ba	440
68a9c7c4 ZJS	441	if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0)
68a9c7c4 ZJS	442	goto found;
e9140aff LP	443	}
e9140aff LP	444
97b11eed	445	addresses = mfree(addresses);
e9140aff	446
1d050e1e	447	n_addresses = local_gateways(NULL, 0, AF_UNSPEC, &addresses);
68a9c7c4 ZJS	448	for (a = addresses, n = 0; (int) n < n_addresses; n++, a++) {
	449	if (af != a->family)
	450	continue;
e9140aff	451
68a9c7c4	452	if (memcmp(addr, &a->address, FAMILY_ADDRESS_SIZE(af)) == 0) {
5248e7e1	453	canonical = "_gateway";
68a9c7c4	454	goto found;
e9140aff	455	}
8041b5ba LP	456	}
8041b5ba LP	457
8041b5ba	458	*h_errnop = HOST_NOT_FOUND;
8041b5ba LP	459	return NSS_STATUS_NOTFOUND;
	460
	461	found:
82e4c2d6	462	if (!canonical \|\| additional_from_hostname) {
3fdcecc8 LP	463	hn = gethostname_malloc();
3fdcecc8 LP	464	if (!hn) {
b26c9041	465	*errnop = DISARM_PROTECT_ERRNO(ENOMEM);
3fdcecc8 LP	466	*h_errnop = NO_RECOVERY;
	467	return NSS_STATUS_TRYAGAIN;
	468	}
	469
	470	if (!canonical)
	471	canonical = hn;
82e4c2d6	472	else
3fdcecc8 LP	473	additional = hn;
3fdcecc8 LP	474	}
4e8c8252	475
e8a7a315 LP	476	return fill_in_hostent(
	477	canonical, additional,
	478	af,
	479	addresses, n_addresses,
	480	local_address_ipv4,
	481	host,
	482	buffer, buflen,
b26c9041	483	errnop, h_errnop, &_saved_errno_,
e8a7a315 LP	484	ttlp,
e8a7a315 LP	485	NULL);
4e8c8252	486	}
6b21f0cf	487
c9fdc26e LP	488	NSS_GETHOSTBYNAME_FALLBACKS(myhostname);
c9fdc26e LP	489	NSS_GETHOSTBYADDR_FALLBACKS(myhostname);