263 lines
9.2 KiB
C
263 lines
9.2 KiB
C
/*
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* Copyright (c) 1989, 1990, 1991 by the University of Washington
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* Copyright (c) 1991, 1992, 1993 by the University of Southern California
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*
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* For copying and distribution information, please see the files
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* <uw-copyright.h> and <usc-copyr.h>.
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*/
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#include <uw-copyright.h>
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#include <usc-copyr.h>
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#include <stdio.h>
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#include <string.h>
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#include <pfs.h>
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#include <perrno.h>
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#include <pmachine.h>
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extern int pfs_debug;
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static PATTRIB expand_amat(PATTRIB ca, VLINK vl);
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static int match_am(PATTRIB list, TOKEN *ainfop, int methods);
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/* Returns the chosen access method, or zero if failure.
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We do NOT modify link, unless the object that is the target oflink was
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forwarded, in which case vl may be returned updated. */
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/* This interface is suboptimal, since it doesn't allow for retries in case
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one of the access methods fails. */
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int
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pget_am(vl,ainfop,methods)
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VLINK vl;
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TOKEN *ainfop; /* This will be filled in with access info
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data. */
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int methods; /* Methods this client supports */
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{
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PATTRIB hits = NULL; /* list of the hits. */
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PATTRIB ats; /* attributes returned by pget_at() */
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PATTRIB ca; /* index variable */
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int retval;
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perrno = PSUCCESS;
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if(strcmp(vl->target,"NULL") == 0)
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return(0);
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*ainfop = (TOKEN) NULL;
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/* For an EXTERNAL link, the access method should be somewhere on
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the lattrib member. This is guaranteed in the protocol. Look on the
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lattrib member in any case, so that we avoid going over the network for
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the ACCESS-METHOD attribute if it was already cached or otherwise
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available (perhaps it was returned as an OBJECT attribute). */
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for (ca = vl->lattrib; ca; ca = ca->next) {
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if (strequal(ca->aname, "ACCESS-METHOD")) {
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PATTRIB amat = expand_amat(ca, vl);
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if (amat) /* if the amat was correctly formed */
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APPEND_ITEM(amat, hits);
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}
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}
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retval = match_am(hits, ainfop, methods);
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if (retval) return retval; /* found a match. */
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/* If no match found on the link's attribute list try to retrieve the
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ACCESS-METHOD attribute directly from the object.
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pget_at() will always return NULL for EXTERNAL links; we take advantage
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of this. */
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hits = NULL; /* no hits for this try. */
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ats = pget_at(vl, "ACCESS-METHOD");
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for (ca = ats; ca; ca = ca->next)
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if (strequal(ca->aname, "ACCESS-METHOD")) {
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PATTRIB amat = expand_amat(ca, vl);
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if (amat) /* if the amat was correctly formed */
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APPEND_ITEM(amat, hits);
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}
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atlfree(ats);
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if (!hits)
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p_err_string = qsprintf_stcopyr(p_err_string, "No ACCESS-METHOD");
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return match_am(hits, ainfop, methods);
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}
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static void wrong_length(PATTRIB ca);
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/* Takes responsibility for freeing the list of attributes passed to it. */
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/* Returns a matching access method found on the list, or zero if failure. */
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static int
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match_am(PATTRIB hits, TOKEN *ainfop, int methods)
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{
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PATTRIB ca;
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/* Now, go through each of the hits, if any. */
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for (ca = hits; ca; ca = ca->next) {
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/* First element of the sequence is the name of the access method. */
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if (!ca->value.sequence) {
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wrong_length(ca); /* Record that it was malformed */
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continue;
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}
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if((methods & P_AM_LOCAL)
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&& (strequal(ca->value.sequence->token,"LOCAL"))) {
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if (length(ca->value.sequence) != 5) {
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wrong_length(ca);
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continue;
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}
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*ainfop = ca->value.sequence;
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ca->value.sequence = (TOKEN) NULL;
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atlfree(hits);
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return(P_AM_LOCAL);
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}
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if((methods & P_AM_NFS)
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&& (strequal(ca->value.sequence->token,"NFS"))) {
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if (length(ca->value.sequence) != 6) {
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wrong_length(ca);
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continue;
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}
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*ainfop = ca->value.sequence;
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ca->value.sequence = (TOKEN) NULL;
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atlfree(hits);
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return(P_AM_NFS);
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}
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if((methods & P_AM_PROSPERO_CONTENTS)
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&& (strequal(ca->value.sequence->token,"PROSPERO-CONTENTS"))) {
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if (length(ca->value.sequence) != 5) {
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wrong_length(ca);
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continue;
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}
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*ainfop = ca->value.sequence;
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ca->value.sequence = (TOKEN) NULL;
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atlfree(hits);
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return(P_AM_PROSPERO_CONTENTS);
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}
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if((methods & P_AM_WAIS)
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&& (strequal(ca->value.sequence->token,"WAIS"))) {
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if (length(ca->value.sequence) != 5) {
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wrong_length(ca);
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continue;
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}
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*ainfop = ca->value.sequence;
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ca->value.sequence = (TOKEN) NULL;
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atlfree(hits);
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return(P_AM_WAIS);
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}
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if((methods & P_AM_TELNET)
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&& (strequal(ca->value.sequence->token,"TELNET"))) {
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if (length(ca->value.sequence) < 5) {
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wrong_length(ca);
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continue;
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}
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*ainfop = ca->value.sequence;
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ca->value.sequence = (TOKEN) NULL;
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atlfree(hits);
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return(P_AM_TELNET);
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}
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if((methods & P_AM_AFS)
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&& (strequal(ca->value.sequence->token,"AFS"))) {
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if (length(ca->value.sequence) != 5) {
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wrong_length(ca);
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continue;
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}
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*ainfop = ca->value.sequence;
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ca->value.sequence = (TOKEN) NULL;
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atlfree(hits);
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return(P_AM_AFS);
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}
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if((methods & P_AM_AFTP)
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&& (strequal(ca->value.sequence->token,"AFTP"))) {
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if (length(ca->value.sequence) != 6) {
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wrong_length(ca);
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continue;
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}
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*ainfop = ca->value.sequence;
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ca->value.sequence = (TOKEN) NULL;
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atlfree(hits);
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return(P_AM_AFTP);
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}
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if((methods & P_AM_GOPHER)
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&& (strequal(ca->value.sequence->token,"GOPHER"))) {
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int len = length(ca->value.sequence);
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if (len != 5 && len != 6) {
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wrong_length(ca);
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continue;
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}
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*ainfop = ca->value.sequence;
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ca->value.sequence = (TOKEN) NULL;
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if (len == 5) {
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/* Canonicalize 5-token format to six-token format internally.
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*/
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TOKEN tmp = tkalloc(" ");
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*(tmp->token) = *elt(*ainfop, 4);
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APPEND_ITEM(tmp, *ainfop);
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}
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atlfree(hits);
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return(P_AM_GOPHER);
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}
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if((methods & P_AM_RCP)
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&& (strequal(ca->value.sequence->token,"RCP"))) {
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if (length(ca->value.sequence) != 5) {
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wrong_length(ca);
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continue;
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}
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*ainfop = ca->value.sequence;
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ca->value.sequence = (TOKEN) NULL;
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atlfree(hits);
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return(P_AM_RCP);
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}
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/* The FTP method requires prompting for a password, which is not
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transparent to the user. Thus, it is the least desirable method,
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from our point of view. */
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if((methods & P_AM_FTP)
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&& (strequal(ca->value.sequence->token,"FTP"))) {
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if (length(ca->value.sequence) != 6) {
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wrong_length(ca);
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continue;
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}
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*ainfop = ca->value.sequence;
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ca->value.sequence = (TOKEN) NULL;
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atlfree(hits);
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return(P_AM_FTP);
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}
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}
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atlfree(hits);
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*ainfop = NULL;
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return 0;
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}
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/* Inform the user of a problem if pfs_debug is set. */
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static void
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wrong_length(PATTRIB ca)
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{
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p_warn_string = qsprintf_stcopyr(p_warn_string,
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"Parse error: the server returned ACCESS-METHOD %s%swith %d \
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elements; not what was expected by pget_am()!",
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length(ca->value.sequence) > 0 ? ca->value.sequence->token : "",
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length(ca->value.sequence) > 0 ? " " : "",
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length(ca->value.sequence));
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if (pfs_debug) {
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fputs(p_warn_string, stderr);
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fputc('\n', stderr);
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}
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pwarn = PWARNING;
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}
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/* Copy an attribute and expand it. */
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static PATTRIB
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expand_amat(PATTRIB ca, VLINK vl)
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{
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TOKEN tk;
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if (length(ca->value.sequence) < 5) return NULL; /* malformed. */
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ca = atcopy(ca); /* don't modify the original. */
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/* atcopy has been fixed to do this properly! - Mitra*/
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#ifdef NEVERDEFINED
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ca->value.sequence = tkcopy(ca->value.sequence); /* copy the data too! */
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#endif
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tk = ca->value.sequence;
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tk = tk->next; /* skip access method name */
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if(*tk->token == '\0') tk->token = stcopyr(vl->hosttype, tk->token);
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tk = tk->next; /* go on */
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if(*tk->token == '\0') tk->token = stcopyr(vl->host, tk->token);
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tk = tk->next; /* go on */
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if(*tk->token == '\0') tk->token = stcopyr(vl->hsonametype, tk->token);
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tk = tk->next; /* go on */
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if(*tk->token == '\0') tk->token = stcopyr(vl->hsoname, tk->token);
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return ca;
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}
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