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-rw-r--r--src/nss-myhostname/nss-myhostname.c451
1 files changed, 451 insertions, 0 deletions
diff --git a/src/nss-myhostname/nss-myhostname.c b/src/nss-myhostname/nss-myhostname.c
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index 0000000000..83180ad805
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+++ b/src/nss-myhostname/nss-myhostname.c
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+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of nss-myhostname.
+
+ Copyright 2008-2011 Lennart Poettering
+
+ nss-myhostname is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public License
+ as published by the Free Software Foundation; either version 2.1 of
+ the License, or (at your option) any later version.
+
+ nss-myhostname is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with nss-myhostname; If not, see
+ <http://www.gnu.org/licenses/>.
+***/
+
+#include <limits.h>
+#include <nss.h>
+#include <sys/types.h>
+#include <netdb.h>
+#include <errno.h>
+#include <string.h>
+#include <assert.h>
+#include <unistd.h>
+#include <net/if.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+
+#include "ifconf.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 "localhost6" or so. */
+
+#define LOCALADDRESS_IPV4 (htonl(0x7F000002))
+#define LOCALADDRESS_IPV6 &in6addr_loopback
+#define LOOPBACK_INTERFACE "lo"
+
+#define ALIGN(a) (((a+sizeof(void*)-1)/sizeof(void*))*sizeof(void*))
+
+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) _public_;
+
+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) _public_;
+
+enum nss_status _nss_myhostname_gethostbyname2_r(
+ const char *name,
+ int af,
+ struct hostent *host,
+ char *buffer, size_t buflen,
+ int *errnop, int *h_errnop) _public_;
+
+enum nss_status _nss_myhostname_gethostbyname_r(
+ const char *name,
+ struct hostent *host,
+ char *buffer, size_t buflen,
+ int *errnop, int *h_errnop) _public_;
+
+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) _public_;
+
+enum nss_status _nss_myhostname_gethostbyaddr_r(
+ const void* addr, socklen_t len,
+ int af,
+ struct hostent *host,
+ char *buffer, size_t buflen,
+ int *errnop, int *h_errnop) _public_;
+
+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) {
+
+ unsigned lo_ifi;
+ char hn[HOST_NAME_MAX+1];
+ size_t l, idx, ms;
+ char *r_name;
+ struct gaih_addrtuple *r_tuple, *r_tuple_prev = NULL;
+ struct address *addresses = NULL, *a;
+ unsigned n_addresses = 0, n;
+
+ memset(hn, 0, sizeof(hn));
+ if (gethostname(hn, sizeof(hn)-1) < 0) {
+ *errnop = errno;
+ *h_errnop = NO_RECOVERY;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ if (strcasecmp(name, hn) != 0) {
+ *errnop = ENOENT;
+ *h_errnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+ }
+
+ /* If this fails, n_addresses is 0. Which is fine */
+ ifconf_acquire_addresses(&addresses, &n_addresses);
+
+ /* If this call fails we fill in 0 as scope. Which is fine */
+ lo_ifi = if_nametoindex(LOOPBACK_INTERFACE);
+
+ l = strlen(hn);
+ ms = ALIGN(l+1)+ALIGN(sizeof(struct gaih_addrtuple))*(n_addresses > 0 ? n_addresses : 2);
+ if (buflen < ms) {
+ *errnop = ENOMEM;
+ *h_errnop = NO_RECOVERY;
+ free(addresses);
+ return NSS_STATUS_TRYAGAIN;
+ }
+
+ /* First, fill in hostname */
+ r_name = buffer;
+ memcpy(r_name, hn, l+1);
+ idx = ALIGN(l+1);
+
+ 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 = (uint32_t) lo_ifi;
+
+ 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 = LOCALADDRESS_IPV4;
+ r_tuple->scopeid = (uint32_t) lo_ifi;
+
+ 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; 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->ifindex;
+ 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);
+
+ *pat = r_tuple_prev;
+
+ if (ttlp)
+ *ttlp = 0;
+
+ free(addresses);
+
+ return NSS_STATUS_SUCCESS;
+}
+
+static enum nss_status fill_in_hostent(
+ const char *hn,
+ int af,
+ struct hostent *result,
+ char *buffer, size_t buflen,
+ int *errnop, int *h_errnop,
+ int32_t *ttlp,
+ char **canonp) {
+
+ size_t l, idx, ms;
+ char *r_addr, *r_name, *r_aliases, *r_addr_list;
+ size_t alen;
+ struct address *addresses = NULL, *a;
+ unsigned n_addresses = 0, n, c;
+
+ alen = PROTO_ADDRESS_SIZE(af);
+
+ ifconf_acquire_addresses(&addresses, &n_addresses);
+
+ for (a = addresses, n = 0, c = 0; n < n_addresses; a++, n++)
+ if (af == a->family)
+ c++;
+
+ l = strlen(hn);
+ ms = ALIGN(l+1)+
+ sizeof(char*)+
+ (c > 0 ? c : 1)*ALIGN(alen)+
+ (c > 0 ? c+1 : 2)*sizeof(char*);
+
+ if (buflen < ms) {
+ *errnop = ENOMEM;
+ *h_errnop = NO_RECOVERY;
+ free(addresses);
+ return NSS_STATUS_TRYAGAIN;
+ }
+
+ /* First, fill in hostname */
+ r_name = buffer;
+ memcpy(r_name, hn, l+1);
+ idx = ALIGN(l+1);
+
+ /* Second, create (empty) aliases array */
+ r_aliases = buffer + idx;
+ *(char**) r_aliases = 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 = LOCALADDRESS_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 = 0;
+
+ for (a = addresses, n = 0; n < n_addresses; a++, n++) {
+ if (af != a->family)
+ continue;
+
+ ((char**) r_addr_list)[i] = (r_addr + i*ALIGN(alen));
+ i++;
+ }
+
+ assert(i == c);
+ ((char**) r_addr_list)[c] = 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;
+
+ free(addresses);
+
+ 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) {
+
+ char hn[HOST_NAME_MAX+1];
+
+ if (af == AF_UNSPEC)
+ af = AF_INET;
+
+ if (af != AF_INET && af != AF_INET6) {
+ *errnop = EAFNOSUPPORT;
+ *h_errnop = NO_DATA;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ memset(hn, 0, sizeof(hn));
+ if (gethostname(hn, sizeof(hn)-1) < 0) {
+ *errnop = errno;
+ *h_errnop = NO_RECOVERY;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ if (strcasecmp(name, hn) != 0) {
+ *errnop = ENOENT;
+ *h_errnop = HOST_NOT_FOUND;
+ return NSS_STATUS_NOTFOUND;
+ }
+
+ return fill_in_hostent(hn, af, host, buffer, buflen, errnop, h_errnop, ttlp, canonp);
+}
+
+enum nss_status _nss_myhostname_gethostbyname2_r(
+ const char *name,
+ int af,
+ struct hostent *host,
+ char *buffer, size_t buflen,
+ int *errnop, int *h_errnop) {
+
+ return _nss_myhostname_gethostbyname3_r(
+ name,
+ af,
+ host,
+ buffer, buflen,
+ errnop, h_errnop,
+ NULL,
+ NULL);
+}
+
+enum nss_status _nss_myhostname_gethostbyname_r(
+ const char *name,
+ struct hostent *host,
+ char *buffer, size_t buflen,
+ int *errnop, int *h_errnop) {
+
+ return _nss_myhostname_gethostbyname3_r(
+ name,
+ AF_UNSPEC,
+ host,
+ buffer, buflen,
+ errnop, h_errnop,
+ NULL,
+ NULL);
+}
+
+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) {
+
+ char hn[HOST_NAME_MAX+1];
+ struct address *addresses = NULL, *a;
+ unsigned n_addresses = 0, n;
+
+ if (len != PROTO_ADDRESS_SIZE(af)) {
+ *errnop = EINVAL;
+ *h_errnop = NO_RECOVERY;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ if (af == AF_INET) {
+
+ if ((*(uint32_t*) addr) == LOCALADDRESS_IPV4)
+ goto found;
+
+ } else if (af == AF_INET6) {
+
+ if (memcmp(addr, LOCALADDRESS_IPV6, 16) == 0)
+ goto found;
+
+ } else {
+ *errnop = EAFNOSUPPORT;
+ *h_errnop = NO_DATA;
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ ifconf_acquire_addresses(&addresses, &n_addresses);
+
+ for (a = addresses, n = 0; n < n_addresses; n++, a++) {
+ if (af != a->family)
+ continue;
+
+ if (memcmp(addr, a->address, PROTO_ADDRESS_SIZE(af)) == 0)
+ goto found;
+ }
+
+ *errnop = ENOENT;
+ *h_errnop = HOST_NOT_FOUND;
+
+ free(addresses);
+ return NSS_STATUS_NOTFOUND;
+
+found:
+ free(addresses);
+
+ memset(hn, 0, sizeof(hn));
+ if (gethostname(hn, sizeof(hn)-1) < 0) {
+ *errnop = errno;
+ *h_errnop = NO_RECOVERY;
+
+ return NSS_STATUS_UNAVAIL;
+ }
+
+ return fill_in_hostent(hn, af, host, buffer, buflen, errnop, h_errnop, ttlp, NULL);
+
+}
+
+enum nss_status _nss_myhostname_gethostbyaddr_r(
+ const void* addr, socklen_t len,
+ int af,
+ struct hostent *host,
+ char *buffer, size_t buflen,
+ int *errnop, int *h_errnop) {
+
+ return _nss_myhostname_gethostbyaddr2_r(
+ addr, len,
+ af,
+ host,
+ buffer, buflen,
+ errnop, h_errnop,
+ NULL);
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-02 05:09:29 +0000