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   <H1>[fetchmail] Patch for IMAP idling where idling is unsupported
   </H1>
    <B>Chris Boyle
    </B> 
    <A HREF="mailto:fetchmail-friends%40cmb.is-a-geek.org"
       TITLE="[fetchmail] Patch for IMAP idling where idling is unsupported">fetchmail-friends@cmb.is-a-geek.org
       </A><BR>
    <I>21 Jul 2003 18:20:43 +0100</I>
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<PRE>Here's a patch I've written: where IDLE is unavailable, it uses periodic
NOOP commands instead (every 28 seconds). Important behavioural change:
the option &quot;idle&quot; will now always result in *some* form of idle. I think
I read somewhere that some servers will unilaterally send status updates
if you just hold the connection open, i.e. NOOPs would be unnecessary,
but that doesn't seem to be the case anywhere I've tried. In any case,
this patch copes with updates both as a response to the NOOPs and
unilaterally sent between them. It functions exactly like normal idling
(N.B. like normal idling, it is single-folder only), and hopefully
includes all the appropriate changes to the documentation. Enjoy. :-)

<A HREF="http://cmb.is-a-geek.org/downloads/fetchmail-6.2.2+noopidle.diff.gz">http://cmb.is-a-geek.org/downloads/fetchmail-6.2.2+noopidle.diff.gz</A>

-- 
Chris Boyle - <A HREF="http://people.debian.org/~cmb/">http://people.debian.org/~cmb/</A>
GPG: B7D86E0F, MSN: <A HREF="mailto:shortcipher@hotmail.com">shortcipher@hotmail.com</A>, ICQ: 24151961,
AIM: kerneloops, Yahoo: kerneloops, IRC: cmb on freenode.net

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generated by cgit v1.2.3 (git 2.46.0) at 2026-07-07 05:41:45 +0000
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/*
 * uid.c -- UIDL handling for POP3 servers without LAST
 *
 * For license terms, see the file COPYING in this directory.
 */

#include "config.h"

#include <sys/stat.h>
#include <errno.h>
#include <stdio.h>
#include <limits.h>
#if defined(STDC_HEADERS)
#include <stdlib.h>
#include <string.h>
#endif
#if defined(HAVE_UNISTD_H)
#include <unistd.h>
#endif

#include "fetchmail.h"

/*
 * Machinery for handling UID lists live here.  This is mainly to support
 * RFC1725-conformant POP3 servers without a LAST command, but may also be
 * useful for making the IMAP4 querying logic UID-oriented, if a future
 * revision of IMAP forces me to.
 *
 * These functions are also used by the rest of the code to maintain
 * string lists.
 *
 * Here's the theory:
 *
 * At start of a query, we have a (possibly empty) list of UIDs to be
 * considered seen in `oldsaved'.  These are messages that were left in
 * the mailbox and *not deleted* on previous queries (we don't need to
 * remember the UIDs of deleted messages because ... well, they're gone!)
 * This list is initially set up by initialize_saved_list() from the
 * .fetchids file.
 *
 * Early in the query, during the execution of the protocol-specific 
 * getrange code, the driver expects that the host's `newsaved' member
 * will be filled with a list of UIDs and message numbers representing
 * the mailbox state.  If this list is empty, the server did
 * not respond to the request for a UID listing.
 *
 * Each time a message is fetched, we can check its UID against the
 * `oldsaved' list to see if it is old.
 *
 * Each time a message-id is seen, we mark it with MARK_SEEN.
 *
 * Each time a message is deleted, we mark its id UID_DELETED in the
 * `newsaved' member.  When we want to assert that an expunge has been
 * done on the server, we call expunge_uid() to register that all
 * deleted messages are gone by marking them UID_EXPUNGED.
 *
 * At the end of the query, the `newsaved' member becomes the
 * `oldsaved' list.  The old `oldsaved' list is freed.
 *
 * At the end of the fetchmail run, seen and non-EXPUNGED members of all
 * current `oldsaved' lists are flushed out to the .fetchids file to
 * be picked up by the next run.  If there are no un-expunged
 * messages, the file is deleted.
 *
 * Note: some comparisons (those used for DNS address lists) are caseblind!  
 */

/* UIDs associated with un-queried hosts */
static struct idlist *scratchlist;

#ifdef POP3_ENABLE
void initialize_saved_lists(struct query *hostlist, const char *idfile)
/* read file of saved IDs and attach to each host */
{
    struct stat statbuf;
    FILE	*tmpfp;
    struct query *ctl;

    /* make sure lists are initially empty */
    for (ctl = hostlist; ctl; ctl = ctl->next)
	ctl->skipped = ctl->oldsaved = ctl->newsaved = (struct idlist *)NULL;

    errno = 0;

    /*
     * Croak if the uidl directory does not exist.
     * This probably means an NFS mount failed and we can't
     * see a uidl file that ought to be there.
     * Question: is this a portable check? It's not clear
     * that all implementations of lstat() will return ENOTDIR
     * rather than plain ENOENT in this case...
     */
   if (lstat(idfile, &statbuf) < 0) {
     if (errno == ENOTDIR) 
    {
      report(stderr, "lstat: %s: %s\n", idfile, strerror(errno));
      exit(PS_IOERR);
    }
   }

    /* let's get stored message UIDs from previous queries */
    if ((tmpfp = fopen(idfile, "r")) != (FILE *)NULL)
    {
	char buf[POPBUFSIZE+1];
	char *host = NULL;	/* pacify -Wall */
	char *user;
	char *id;
	char *atsign;	/* temp pointer used in parsing user and host */
	char *delimp1;
	char saveddelim1;
	char *delimp2;
	char saveddelim2 = '\0';	/* pacify -Wall */

	while (fgets(buf, POPBUFSIZE, tmpfp) != (char *)NULL)
	{
	    /*
	     * At this point, we assume the bug has two fields -- a user@host 
	     * part, and an ID part. Either field may contain spurious @ signs.
	     * The previous version of this code presumed one could split at 
	     * the rightmost '@'.  This is not correct, as InterMail puts an 
	     * '@' in the UIDL.
	     */
	  
	    /* first, skip leading spaces */
	    user = buf + strspn(buf, " \t");

	    /*
	     * First, we split the buf into a userhost part and an id
	     * part ... but id doesn't necessarily start with a '<',
	     * espescially if the POP server returns an X-UIDL header
	     * instead of a Message-ID, as GMX's (www.gmx.net) POP3
	     * StreamProxy V1.0 does.
	     */
	    if ((id = strchr(user, ' ')) != NULL )
	    {
	        for (delimp1 = id; delimp1 >= user; delimp1--)
		    if ((*delimp1 != ' ') && (*delimp1 != '\t'))
			break;

		/* 
		 * It should be safe to assume that id starts after
		 * the " " - after all, we're writing the " "
		 * ourselves in write_saved_lists() :-)
		 */
		id = id + strspn(id, " ");

		delimp1++; /* but what if there is only white space ?!? */
	  	saveddelim1 = *delimp1;	/* save char after token */
		*delimp1 = '\0';		/* delimit token with \0 */
		if (id != NULL) 
		{
		    /* now remove trailing white space chars from id */
		    if ((delimp2 = strpbrk(id, " \t\n")) != NULL ) {
			saveddelim2 = *delimp2;
			*delimp2 = '\0';
		    }
		    atsign = strrchr(user, '@');
		    if (atsign) {
			*atsign = '\0';
			host = atsign + 1;

		    }
		    for (ctl = hostlist; ctl; ctl = ctl->next) {
			if (ctl->server.truename &&
			    strcasecmp(host, ctl->server.truename) == 0
			    && strcasecmp(user, ctl->remotename) == 0) {
	
			    save_str(&ctl->oldsaved, id, UID_SEEN);
			    break;
			}
		    }
		    /* if it's not in a host we're querying,
		    ** save it anyway */
		    if (ctl == (struct query *)NULL) {
				/* restore string */
			*delimp1 = saveddelim1;
			*atsign = '@';
			if (delimp2 != NULL) {
			    *delimp2 = saveddelim2;
			}
			save_str(&scratchlist, buf, UID_SEEN);
		    }
		}
	    }
	}
	fclose(tmpfp);	/* not checking should be safe, mode was "r" */
    }

    if (outlevel >= O_DEBUG)
    {
	struct idlist	*idp;
	int uidlcount = 0;

	for (ctl = hostlist; ctl; ctl = ctl->next)
	    if (ctl->server.uidl)
	    {
		report_build(stdout, "Old UID list from %s:",ctl->server.pollname);
		for (idp = ctl->oldsaved; idp; idp = idp->next)
		    report_build(stdout, " %s", idp->id);
		if (!idp)
		    report_build(stdout, " <empty>");
		report_complete(stdout, "\n");
		uidlcount++;
	    }

	if (uidlcount)
	{
	    report_build(stdout, "Scratch list of UIDs:");
	    for (idp = scratchlist; idp; idp = idp->next)
		report_build(stdout, " %s", idp->id);
	    if (!idp)
		report_build(stdout, " <empty>");
	    report_complete(stdout, "\n");
	}
    }
}
#endif /* POP3_ENABLE */

struct idlist *save_str(struct idlist **idl, const char *str, flag status)
/* save a number/UID pair on the given UID list */
{
    struct idlist **end;

    /* do it nonrecursively so the list is in the right order */
    for (end = idl; *end; end = &(*end)->next)
	continue;

    *end = (struct idlist *)xmalloc(sizeof(struct idlist));
    (*end)->val.status.mark = status;
    (*end)->id = str ? xstrdup(str) : (char *)NULL;
    (*end)->next = NULL;

    return(*end);
}

void free_str_list(struct idlist **idl)
/* free the given UID list */
{
    if (*idl == (struct idlist *)NULL)
	return;

    free_str_list(&(*idl)->next);
    free ((*idl)->id);
    free(*idl);
    *idl = (struct idlist *)NULL;
}

void save_str_pair(struct idlist **idl, const char *str1, const char *str2)
/* save an ID pair on the given list */
{
    struct idlist **end;

    /* do it nonrecursively so the list is in the right order */
    for (end = idl; *end; end = &(*end)->next)
	continue;

    *end = (struct idlist *)xmalloc(sizeof(struct idlist));
    (*end)->id = str1 ? xstrdup(str1) : (char *)NULL;
    if (str2)
	(*end)->val.id2 = xstrdup(str2);
    else
	(*end)->val.id2 = (char *)NULL;
    (*end)->next = (struct idlist *)NULL;
}

#ifdef __UNUSED__
void free_str_pair_list(struct idlist **idl)
/* free the given ID pair list */
{
    if (*idl == (struct idlist *)NULL)
	return;

    free_idpair_list(&(*idl)->next);
    free ((*idl)->id);
    free ((*idl)->val.id2);
    free(*idl);
    *idl = (struct idlist *)NULL;
}
#endif

int str_in_list(struct idlist **idl, const char *str, const flag caseblind)
/* is a given ID in the given list? (comparison may be caseblind) */
{
    if (*idl == (struct idlist *)NULL || str == (char *) NULL)
	return(0);
    else if (!caseblind && strcmp(str, (*idl)->id) == 0)
	return(1);
    else if (caseblind && strcasecmp(str, (*idl)->id) == 0)
	return(1);
    else
	return(str_in_list(&(*idl)->next, str, caseblind));
}

int str_nr_in_list( struct idlist **idl, const char *str )
  /* return the position of str in idl */
{
    int nr;
    struct idlist *walk;
    if ( !str )
        return -1;
    for( walk = *idl, nr = 0; walk; nr ++, walk = walk->next )
        if( strcmp( str, walk->id) == 0 )
	    return nr;
    return -1;
}

int str_nr_last_in_list( struct idlist **idl, const char *str)
/* return the last position of str in idl */
{
    int nr, ret = -1;
    struct idlist *walk;
    if ( !str )
        return -1;
    for( walk = *idl, nr = 0; walk; nr ++, walk = walk->next )
        if( strcmp( str, walk->id) == 0 )
	    ret = nr;
    return ret;
}

void str_set_mark( struct idlist **idl, const char *str, const flag val)
/* update the mark on an of an id to given value */
{
    int nr;
    struct idlist *walk;
    if (!str)
        return;
    for(walk = *idl, nr = 0; walk; nr ++, walk = walk->next)
        if (strcmp(str, walk->id) == 0)
	    walk->val.status.mark = val;
}

int count_list( struct idlist **idl)
/* count the number of elements in the list */
{
  if( !*idl )
    return 0;
  return 1 + count_list( &(*idl)->next );
}

char *str_from_nr_list(struct idlist **idl, int number)
/* return the number'th string in idl */
{
    if( !*idl  || number < 0)
        return 0;
    if( number == 0 )
        return (*idl)->id;
    return str_from_nr_list(&(*idl)->next, number-1);
}

    
char *str_find(struct idlist **idl, int number)
/* return the id of the given number in the given list. */
{
    if (*idl == (struct idlist *) 0)
	return((char *) 0);
    else if (number == (*idl)->val.status.num)
	return((*idl)->id);
    else
	return(str_find(&(*idl)->next, number));
}

char *idpair_find(struct idlist **idl, const char *id)
/* return the id of the given id in the given list (caseblind comparison) */
{
    if (*idl == (struct idlist *) 0)
	return((char *) 0);
    else if (strcasecmp(id, (*idl)->id) == 0)
	return((*idl)->val.id2 ? (*idl)->val.id2 : (*idl)->id);
    else
	return(idpair_find(&(*idl)->next, id));
}

int delete_str(struct idlist **idl, int num)
/* delete given message from given list */
{
    struct idlist	*idp;

    for (idp = *idl; idp; idp = idp->next)
	if (idp->val.status.num == num)
	{
	    idp->val.status.mark = UID_DELETED;
	    return(1);
	}
    return(0);
}

void append_str_list(struct idlist **idl, struct idlist **nidl)
/* append nidl to idl (does not copy *) */
{
    if ((*nidl) == (struct idlist *)NULL || *nidl == *idl)
	return;
    else if ((*idl) == (struct idlist *)NULL)
	*idl = *nidl;
    else if ((*idl)->next == (struct idlist *)NULL)
	(*idl)->next = *nidl;
    else if ((*idl)->next != *nidl)
	append_str_list(&(*idl)->next, nidl);
}

#ifdef POP3_ENABLE
void expunge_uids(struct query *ctl)
/* assert that all UIDs marked deleted have actually been expunged */
{
    struct idlist *idl;

    for (idl = ctl->newsaved; idl; idl = idl->next)
	if (idl->val.status.mark == UID_DELETED)
	    idl->val.status.mark = UID_EXPUNGED;
}

void uid_end_query(struct query *ctl) 
/* finish a query */
{
    /* debugging code */
    if (ctl->server.uidl && outlevel >= O_DEBUG)
    {
	struct idlist *idp;

	report_build(stdout, "New UID list from %s:", ctl->server.pollname);
	for (idp = ctl->newsaved; idp; idp = idp->next)
	    report_build(stdout, " %s = %d", idp->id, idp->val.status.mark);
	if (!idp)
	    report_build(stdout, " <empty>");
	report_complete(stdout, "\n");
    }

    /* old state of mailbox may now be irrelevant */
    free_str_list(&ctl->oldsaved);
    free_str_list(&scratchlist);
    ctl->oldsaved = ctl->newsaved;
    ctl->newsaved = (struct idlist *) NULL;
}

void write_saved_lists(struct query *hostlist, const char *idfile)
/* perform end-of-run write of seen-messages list */
{
    int		idcount;
    FILE	*tmpfp;
    struct query *ctl;
    struct idlist *idp;

    /* if all lists are empty, nuke the file */
    idcount = 0;
    for (ctl = hostlist; ctl; ctl = ctl->next) {
	if (ctl->oldsaved)
	    idcount++;
    }

    /* either nuke the file or write updated last-seen IDs */
    if (!idcount && !scratchlist)
    {
	if (outlevel >= O_DEBUG)
	    report(stdout, "Deleting fetchids file.\n");
	unlink(idfile);
    }
    else
    {
	if (outlevel >= O_DEBUG)
	    report(stdout, "Writing fetchids file.\n");
	if ((tmpfp = fopen(idfile, "w")) != (FILE *)NULL) {
	    for (ctl = hostlist; ctl; ctl = ctl->next) {
		for (idp = ctl->oldsaved; idp; idp = idp->next)
		    if (idp->val.status.mark == UID_SEEN
				|| idp->val.status.mark == UID_DELETED)
			fprintf(tmpfp, "%s@%s %s\n", 
			    ctl->remotename, ctl->server.truename, idp->id);
	    }
	    for (idp = scratchlist; idp; idp = idp->next)
		fputs(idp->id, tmpfp);
	    fclose(tmpfp);
	}
    }
}
#endif /* POP3_ENABLE */

/* uid.c ends here */
generated by cgit v1.2.3 (git 2.46.0) at 2026-07-07 05:41:44 +0000