mirror of
git://git.gnupg.org/gnupg.git
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445 lines
11 KiB
C
445 lines
11 KiB
C
/* gpgkeys_kdns.c - Fetch a key via the GnuPG specific KDNS scheme.
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* Copyright (C) 2008 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <unistd.h>
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#ifdef HAVE_GETOPT_H
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# include <getopt.h>
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#endif
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#include <assert.h>
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#ifdef HAVE_ADNS_H
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# include <adns.h>
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# ifndef HAVE_ADNS_FREE
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# define adns_free free
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# endif
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#endif
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#define INCLUDED_BY_MAIN_MODULE 1
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#include "util.h"
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#include "keyserver.h"
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#include "ksutil.h"
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/* Our own name. */
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#define PGM "gpgkeys_kdns"
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/* getopt(3) requires declarion of some global variables. */
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extern char *optarg;
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extern int optind;
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/* Convenience variables usually intialized withn std{in,out,err}. */
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static FILE *input, *output, *console;
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/* Standard keyserver module options. */
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static struct ks_options *opt;
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/* The flags we pass to adns_init: Do not allow any environment
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variables and for now enable debugging. */
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#define MY_ADNS_INITFLAGS (adns_if_noenv)
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/* ADNS has no support for CERT yes. */
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#define my_adns_r_cert 37
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/* The root of the KDNS tree. */
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static const char *kdns_root;
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/* The replacement string for the at sign. */
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static const char *kdns_at_repl;
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/* Flag indicating that a TCP conenction should be used. */
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static int kdns_usevc;
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/* Retrieve one key. ADDRESS should be an RFC-2822 addr-spec. */
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static int
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get_key (adns_state adns_ctx, char *address)
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{
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int ret = KEYSERVER_INTERNAL_ERROR;
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const char *domain;
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char *name = NULL;
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adns_answer *answer = NULL;
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const unsigned char *data;
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int datalen;
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struct b64state b64state;
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char *p;
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domain = strrchr (address, '@');
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if (!domain || domain == address || !domain[1])
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{
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fprintf (console, PGM": invalid mail address `%s'\n", address);
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ret = KEYSERVER_GENERAL_ERROR;
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goto leave;
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}
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name = xtrymalloc (strlen (address) + strlen (kdns_at_repl)
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+ 1 + strlen (kdns_root) + 1);
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if (!name)
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goto leave;
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memcpy (name, address, domain - address);
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p = stpcpy (name + (domain-address), ".");
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if (*kdns_at_repl)
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p = stpcpy (stpcpy (p, kdns_at_repl), ".");
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p = stpcpy (p, domain+1);
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if (*kdns_root)
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strcpy (stpcpy (p, "."), kdns_root);
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fprintf (output,"NAME %s BEGIN\n", address);
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if (opt->verbose > 2)
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fprintf(console, PGM": looking up `%s'\n", name);
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if ( adns_synchronous (adns_ctx, name, (adns_r_unknown | my_adns_r_cert),
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adns_qf_quoteok_query|(kdns_usevc?adns_qf_usevc:0),
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&answer) )
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{
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fprintf (console, PGM": DNS query failed: %s\n", strerror (errno));
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ret = KEYSERVER_KEY_NOT_FOUND;
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goto leave;
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}
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if (answer->status != adns_s_ok)
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{
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fprintf (console, PGM": DNS query returned: %s (%s)\n",
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adns_strerror (answer->status),
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adns_errabbrev (answer->status));
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ret = KEYSERVER_KEY_NOT_FOUND;
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goto leave;
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}
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datalen = answer->rrs.byteblock->len;
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data = answer->rrs.byteblock->data;
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if ( opt->debug > 1 )
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{
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int i;
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fprintf (console, "got %d bytes of data:", datalen);
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for (i=0; i < datalen; i++)
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{
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if (!(i % 32))
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fprintf (console, "\n%08x ", i);
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fprintf (console, "%02x", data[i]);
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}
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putc ('\n', console);
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}
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if ( datalen < 5 )
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{
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fprintf (console, PGM": error: truncated CERT record\n");
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ret = KEYSERVER_KEY_NOT_FOUND;
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goto leave;
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}
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switch ( ((data[0]<<8)|data[1]) )
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{
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case 3: /* CERT type is PGP. */
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/* (key tag and algorithm fields are ignored for this CERT type). */
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data += 5;
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datalen -= 5;
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if ( datalen < 11 )
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{
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/* Gpg checks for a minium length of 11, thus we do the same. */
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fprintf (console, PGM": error: OpenPGP data to short\n");
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ret = KEYSERVER_KEY_NOT_FOUND;
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goto leave;
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}
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if (b64enc_start (&b64state, output, "PGP PUBLIC KEY BLOCK")
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|| b64enc_write (&b64state, data, datalen)
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|| b64enc_finish (&b64state))
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goto leave; /* Oops, base64 encoder failed. */
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break;
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default:
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fprintf (console, PGM": CERT type %d ignored\n", (data[0] <<8|data[1]));
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ret = KEYSERVER_KEY_NOT_FOUND;
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goto leave;
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}
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ret = 0; /* All fine. */
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leave:
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if (ret)
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fprintf (output, "\nNAME %s FAILED %d\n", address, ret);
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else
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fprintf (output, "\nNAME %s END\n", address);
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adns_free (answer);
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xfree (name);
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return ret;
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}
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/* Print some help. */
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static void
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show_help (FILE *fp)
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{
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fputs (PGM" (GnuPG) " VERSION"\n\n", fp);
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fputs (" -h\thelp\n"
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" -V\tversion\n"
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" -o\toutput to this file\n"
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"\n", fp);
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fputs ("This keyserver helper accepts URLs of the form:\n"
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" kdns://[NAMESERVER]/[ROOT][?at=STRING]\n"
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"with\n"
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" NAMESERVER used for queries (default: system standard)\n"
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" ROOT a DNS name appended to the query (default: none)\n"
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" STRING a string to replace the '@' (default: \".\")\n"
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"If a long answer is expected add the parameter \"usevc=1\".\n"
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"\n", fp);
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fputs ("Example: A query for \"hacker@gnupg.org\" with\n"
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" kdns://10.0.0.1/example.net?at=_key&usevc=1\n"
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"setup as --auto-key-lookup does a CERT record query\n"
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"with type PGP on the nameserver 10.0.0.1 for\n"
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" hacker._key_.gnupg.org.example.net\n"
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"\n", fp);
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}
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int
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main (int argc, char *argv[])
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{
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int arg;
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int ret = KEYSERVER_INTERNAL_ERROR;
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char line[MAX_LINE];
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struct keylist *keylist = NULL;
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struct keylist **keylist_tail = &keylist;
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struct keylist *akey;
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int failed = 0;
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adns_state adns_ctx = NULL;
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adns_initflags my_adns_initflags = MY_ADNS_INITFLAGS;
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int tmprc;
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/* The defaults for the KDNS name mangling. */
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kdns_root = "";
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kdns_at_repl = "";
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console = stderr;
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/* Kludge to implement standard GNU options. */
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if (argc > 1 && !strcmp (argv[1], "--version"))
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{
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fputs (PGM" (GnuPG) " VERSION"\n", stdout);
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return 0;
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}
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else if (argc > 1 && !strcmp (argv[1], "--help"))
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{
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show_help (stdout);
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return 0;
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}
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while ( (arg = getopt (argc, argv, "hVo:")) != -1 )
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{
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switch(arg)
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{
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case 'V':
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printf ("%d\n%s\n", KEYSERVER_PROTO_VERSION, VERSION);
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return KEYSERVER_OK;
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case 'o':
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output = fopen (optarg,"w");
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if (!output)
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{
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fprintf (console, PGM": cannot open output file `%s': %s\n",
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optarg, strerror(errno) );
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return KEYSERVER_INTERNAL_ERROR;
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}
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break;
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case 'h':
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default:
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show_help (console);
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return KEYSERVER_OK;
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}
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}
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if (argc > optind)
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{
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input = fopen (argv[optind], "r");
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if (!input)
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{
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fprintf (console, PGM": cannot open input file `%s': %s\n",
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argv[optind], strerror(errno) );
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return KEYSERVER_INTERNAL_ERROR;
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}
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}
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if (!input)
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input = stdin;
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if (!output)
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output = stdout;
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opt = init_ks_options();
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if(!opt)
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return KEYSERVER_NO_MEMORY;
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/* Get the command and info block */
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while ( fgets(line,MAX_LINE,input) )
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{
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int err;
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if(line[0]=='\n')
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break;
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err = parse_ks_options (line, opt);
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if (err > 0)
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{
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ret = err;
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goto leave;
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}
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else if (!err)
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continue;
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}
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if (opt->timeout && register_timeout() == -1 )
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{
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fprintf (console, PGM": unable to register timeout handler\n");
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return KEYSERVER_INTERNAL_ERROR;
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}
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if (opt->verbose)
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{
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fprintf (console, PGM": HOST=%s\n", opt->host? opt->host:"(none)");
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fprintf (console, PGM": PATH=%s\n", opt->path? opt->path:"(none)");
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}
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if (opt->path && *opt->path == '/')
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{
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char *p, *pend;
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kdns_root = opt->path+1;
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p = strchr (opt->path+1, '?');
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if (p)
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{
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*p++ = 0;
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do
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{
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pend = strchr (p, '&');
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if (pend)
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*pend++ = 0;
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if (!strncmp (p, "at=", 3))
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kdns_at_repl = p+3;
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else if (!strncmp (p, "usevc=", 6))
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kdns_usevc = !!atoi (p+6);
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}
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while ((p = pend));
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}
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}
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if (strchr (kdns_root, '/'))
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{
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fprintf (console, PGM": invalid character in KDNS root\n");
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return KEYSERVER_GENERAL_ERROR;
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}
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if (!strcmp (kdns_at_repl, "."))
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kdns_at_repl = "";
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if (opt->verbose)
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{
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fprintf (console, PGM": kdns_root=%s\n", kdns_root);
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fprintf (console, PGM": kdns_at=%s\n", kdns_at_repl);
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fprintf (console, PGM": kdns_usevc=%d\n", kdns_usevc);
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}
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if (opt->debug)
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my_adns_initflags |= adns_if_debug;
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if (opt->host)
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{
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char cfgtext[200];
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snprintf (cfgtext, sizeof cfgtext, "nameserver %s\n", opt->host);
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tmprc = adns_init_strcfg (&adns_ctx, my_adns_initflags, console,cfgtext);
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}
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else
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tmprc = adns_init (&adns_ctx, my_adns_initflags, console);
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if (tmprc)
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{
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fprintf (console, PGM": error initializing ADNS: %s\n",
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strerror (errno));
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goto leave;
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}
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if (opt->action == KS_GETNAME)
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{
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while ( fgets (line,MAX_LINE,input) )
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{
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if (line[0]=='\n' || !line[0] )
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break;
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line[strlen(line)-1] = 0; /* Trim the trailing LF. */
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akey = xtrymalloc (sizeof *akey);
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if (!akey)
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{
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fprintf (console,
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PGM": out of memory while building key list\n");
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ret = KEYSERVER_NO_MEMORY;
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goto leave;
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}
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assert (sizeof (akey->str) > strlen(line));
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strcpy (akey->str, line);
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akey->next = NULL;
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*keylist_tail = akey;
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keylist_tail = &akey->next;
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}
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}
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else
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{
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fprintf (console,
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PGM": this keyserver type only supports "
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"key retrieval by name\n");
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goto leave;
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}
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/* Send the response */
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fprintf (output, "VERSION %d\n", KEYSERVER_PROTO_VERSION);
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fprintf (output, "PROGRAM %s\n\n", VERSION);
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if (opt->verbose > 1)
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{
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if (opt->opaque)
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fprintf (console, "User:\t\t%s\n", opt->opaque);
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fprintf (console, "Command:\tGET\n");
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}
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for (akey = keylist; akey; akey = akey->next)
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{
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set_timeout (opt->timeout);
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if ( get_key (adns_ctx, akey->str) )
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failed++;
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}
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if (!failed)
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ret = KEYSERVER_OK;
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leave:
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if (adns_ctx)
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adns_finish (adns_ctx);
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while (keylist)
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{
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akey = keylist->next;
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xfree (keylist);
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keylist = akey;
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}
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if (input != stdin)
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fclose (input);
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if (output != stdout)
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fclose (output);
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kdns_root = "";
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kdns_at_repl = ".";
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free_ks_options (opt);
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return ret;
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}
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