/* Copyright (C) 1999 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@cygnus.com>, 1999. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU C Library 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 Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include <assert.h> #include <ctype.h> #include <errno.h> #include <netdb.h> #include <stdlib.h> #include <string.h> #include <arpa/inet.h> #include "nsswitch.h" /* We avoid using a too large buffer in case the user is accumulating the results and there is lots of unused space in the allocated buffer. */ #define BUFLEN 512 /* Internal function to test whether IPv4 and/or IPv6 are available. */ extern void __protocol_available (int *have_inet, int *have_inet6) internal_function; /* Type of the lookup function we need here. */ typedef enum nss_status (*lookup_function) (const char *, int, int, struct hostent *, char *, size_t, int *, int *); /* The lookup function for the first entry of this service. */ extern int __nss_hosts_lookup (service_user **nip, const char *name, void **fctp); struct hostent * getipnodebyname (const char *name, int type, int flags, int *h_errnop) { static service_user *startp; static lookup_function start_fct; service_user *nip; lookup_function fct; int no_more; size_t buffer_size; char *buffer; struct hostent *result; int save; int have_inet = 1; int have_inet6 = 1; /* First determine whether we have the appropriate interfaces. XXX I don't think we can cache the result since the system can be reconfigured. */ if ((flags & AI_ADDRCONFIG) != 0) __protocol_available (&have_inet, &have_inet6); /* Handle impossible requests first. */ if ((type == AF_INET && have_inet == 0) || (type == AF_INET6 && have_inet6 == 0 && ((flags & AI_V4MAPPED) == 0 || have_inet == 0)) || (type != AF_INET && type != AF_INET6)) { *h_errnop = NO_DATA; return NULL; } buffer_size = BUFLEN; buffer = (char *) malloc (buffer_size); result = NULL; if (buffer != NULL) { #define HAVE_TYPE #define resbuf (*((struct hostent *) buffer)) #include "../nss/digits_dots.c" } if (startp == NULL) { no_more = __nss_hosts_lookup (&nip, "getipnodebyname_r", (void **) &fct); if (no_more) startp = (service_user *) -1l; else { startp = nip; start_fct = fct; } } else { fct = start_fct; no_more = (nip = startp) == (service_user *) -1l; } /* First do a lookup with the original protocol type. */ while (no_more == 0 && buffer != NULL) { enum nss_status status; status = DL_CALL_FCT (fct, (name, type, ((flags & AI_ALL) ? flags : (flags & ~AI_V4MAPPED)), (struct hostent *) buffer, (char *) ((struct hostent *) buffer + 1), buffer_size - sizeof (struct hostent), &errno, h_errnop)); if (status == NSS_STATUS_SUCCESS) { result = (struct hostent *) buffer; break; } if (status == NSS_STATUS_TRYAGAIN && *h_errnop == NETDB_INTERNAL && errno == ERANGE) { /* Resize the buffer, it's too small. */ buffer_size += BUFLEN; buffer = (char *) realloc (buffer, buffer_size); continue; } no_more = __nss_next (&nip, "getipnodebyname_r", (void **) &fct, status, 0); } /* If we are looking for an IPv6 address but haven't found any and do not have the AI_ALL but the AI_V4MAPPED flag set, now try looking up an IPv4 address and map it. */ if (buffer != NULL && result == NULL && type == AF_INET6 && (flags & AI_V4MAPPED) != 0 && (no_more = (nip = startp) == (service_user *) -1l) == 0) { /* We have to use a new buffer if there is already a result. */ fct = start_fct; do { enum nss_status status; status = DL_CALL_FCT (fct, (name, type, flags, (struct hostent *) buffer, (char *) ((struct hostent *) buffer + 1), buffer_size - sizeof (struct hostent), &errno, h_errnop)); if (status == NSS_STATUS_SUCCESS) { result = (struct hostent *) buffer; break; } if (status == NSS_STATUS_TRYAGAIN && *h_errnop == NETDB_INTERNAL && errno == ERANGE) { /* Resize the buffer, it's too small. */ buffer_size += BUFLEN; buffer = (char *) realloc (buffer, buffer_size); continue; } no_more = __nss_next (&nip, "getipnodebyname_r", (void **) &fct, status, 0); } while (no_more == 0 && buffer != NULL); } done: if (buffer == NULL) { /* We are out of memory. */ *h_errnop = TRY_AGAIN; assert (result == NULL); } else if (result == NULL && buffer != NULL) free (buffer); return result; }