diff options
Diffstat (limited to 'inet/getipnodebynm.c')
| -rw-r--r-- | inet/getipnodebynm.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/inet/getipnodebynm.c b/inet/getipnodebynm.c new file mode 100644 index 0000000..b0be882 --- /dev/null +++ b/inet/getipnodebynm.c @@ -0,0 +1,194 @@ +/* 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; +} |