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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 <stdio.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. (This would be bad. Server-side
* seen bits are better than UIDs, because they track messages seen by
* *all* clients.)
*
* 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 initialized_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. If not, it should be downloaded
* (and possibly deleted). It should be downloaded anyway if --all
* is on. It should not be deleted if --keep is on.
*
* Each time a message is deleted, we remove its id from the `newsaved'
* member.
*
* At the end of the query, whatever remains in the `newsaved' member
* (because it was not deleted) becomes the `oldsaved' list. The old
* `oldsaved' list is freed.
*
* At the end of the fetchmail run, all current `oldsaved' lists are
* flushed out to the .fetchids file to be picked up by the next run.
* If there are no such messages, the file is deleted.
*/
/* UIDs associated with un-queried hosts */
static struct idlist *scratchlist;
void initialize_saved_lists(struct query *hostlist, const char *idfile)
/* read file of saved IDs and attach to each host */
{
int st;
FILE *tmpfp;
struct query *ctl;
/* make sure lists are initially empty */
for (ctl = hostlist; ctl; ctl = ctl->next)
ctl->oldsaved = ctl->newsaved = (struct idlist *)NULL;
/* let's get stored message UIDs from previous queries */
if ((tmpfp = fopen(idfile, "r")) != (FILE *)NULL) {
char buf[POPBUFSIZE+1],host[HOSTLEN+1],user[USERNAMELEN+1],id[IDLEN+1];
while (fgets(buf, POPBUFSIZE, tmpfp) != (char *)NULL)
{
/* possible lossage here with very old versions of sscanf(3)... */
if ((st = sscanf(buf, "%[^@]@%s %s\n", host, user, id)) == 3)
{
for (ctl = hostlist; ctl; ctl = ctl->next)
{
if (strcmp(host, ctl->servername) == 0
&& strcmp(user, ctl->remotename) == 0)
{
save_uid(&ctl->oldsaved, -1, id);
break;
}
}
/* if it's not in a host we're querying, save it anyway */
if (ctl == (struct query *)NULL)
save_uid(&scratchlist, -1, buf);
}
}
fclose(tmpfp);
}
}
struct idlist *save_uid(struct idlist **idl, int num, const char *str)
/* save a number/UID pair on the given UID list */
{
struct idlist *new;
new = (struct idlist *)xmalloc(sizeof(struct idlist));
new->val.num = num;
new->id = xstrdup(str);
new->next = *idl;
*idl = new;
return(new);
}
void free_uid_list(struct idlist **idl)
/* free the given UID list */
{
if (*idl == (struct idlist *)NULL)
return;
free_uid_list(&(*idl)->next);
free ((*idl)->id);
free(*idl);
*idl = (struct idlist *)NULL;
}
void save_id_pair(struct idlist **idl, const char *str1, const char *str2)
/* save an ID pair on the given list */
{
struct idlist *new;
new = (struct idlist *)xmalloc(sizeof(struct idlist));
new->id = xstrdup(str1);
if (str2)
new->val.id2 = xstrdup(str2);
else
new->val.id2 = (char *)NULL;
new->next = *idl;
*idl = new;
}
#ifdef __UNUSED__
void free_idpair_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 uid_in_list(struct idlist **idl, const char *str)
/* is a given ID in the given list? */
{
if (*idl == (struct idlist *)NULL || str == (char *) NULL)
return(0);
else if (strcmp(str, (*idl)->id) == 0)
return(1);
else
return(uid_in_list(&(*idl)->next, str));
}
char *uid_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.num)
return((*idl)->id);
else
return(uid_find(&(*idl)->next, number));
}
char *idpair_find(struct idlist **idl, const char *id)
/* return the id of the given number in the given list. */
{
if (*idl == (struct idlist *) 0)
return((char *) 0);
else if (strcmp(id, (*idl)->id) == 0)
return((*idl)->val.id2 ? (*idl)->val.id2 : (*idl)->id);
else
return(idpair_find(&(*idl)->next, id));
}
int delete_uid(struct idlist **idl, int num)
/* delete given message from given list */
{
if (*idl == (struct idlist *)NULL)
return(0);
else if ((*idl)->val.num == num)
{
struct idlist *next = (*idl)->next;
free ((*idl)->id);
free(*idl);
*idl = next;
return(1);
}
else
return(delete_uid(&(*idl)->next, num));
return(0);
}
void append_uid_list(struct idlist **idl, struct idlist **nidl)
/* append nidl to idl (does not copy *) */
{
if ((*idl) == (struct idlist *)NULL)
*idl = *nidl;
else if ((*idl)->next == (struct idlist *)NULL)
(*idl)->next = *nidl;
else
append_uid_list(&(*idl)->next, nidl);
}
void update_uid_lists(struct query *ctl)
/* perform end-of-query actions on UID lists */
{
free_uid_list(&ctl->oldsaved);
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)
unlink(idfile);
else
if ((tmpfp = fopen(idfile, "w")) != (FILE *)NULL) {
for (ctl = hostlist; ctl; ctl = ctl->next) {
for (idp = ctl->oldsaved; idp; idp = idp->next)
fprintf(tmpfp, "%s@%s %s\n",
ctl->remotename, ctl->servername, idp->id);
}
for (idp = scratchlist; idp; idp = idp->next)
fputs(idp->id, tmpfp);
fclose(tmpfp);
}
}
/* uid.c ends here */
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