+/*************************************************
+* Handle a check for previously-seen *
+*************************************************/
+
+/*
+ACL clauses like: seen = -5m / key=$foo / readonly
+
+Return is true for condition-true - but the semantics
+depend heavily on the actual use-case.
+
+Negative times test for seen-before, positive for seen-more-recently-than
+(the given interval before current time).
+
+All are subject to history not having been cleaned from the DB.
+
+Default for seen-before is to create if not present, and to
+update if older than 10d (with the seen-test time).
+Default for seen-since is to always create or update.
+
+Options:
+ key=value. Default key is $sender_host_address
+ readonly
+ write
+ refresh=<interval>: update an existing DB entry older than given
+ amount. Default refresh lacking this option is 10d.
+ The update sets the record timestamp to the seen-test time.
+
+XXX do we need separate nocreate, noupdate controls?
+
+Arguments:
+ arg the option string for seen=
+ where ACL_WHERE_xxxx indicating which ACL this is
+ log_msgptr for error messages
+
+Returns: OK - Condition is true
+ FAIL - Condition is false
+ DEFER - Problem opening history database
+ ERROR - Syntax error in options
+*/
+
+static int
+acl_seen(const uschar * arg, int where, uschar ** log_msgptr)
+{
+enum { SEEN_DEFAULT, SEEN_READONLY, SEEN_WRITE };
+
+const uschar * list = arg;
+int slash = '/', interval, mode = SEEN_DEFAULT, yield = FAIL;
+BOOL before;
+int refresh = 10 * 24 * 60 * 60; /* 10 days */
+const uschar * ele, * key = sender_host_address;
+open_db dbblock, * dbm;
+dbdata_seen * dbd;
+time_t now;
+
+/* Parse the first element, the time-relation. */
+
+if (!(ele = string_nextinlist(&list, &slash, NULL, 0)))
+ goto badparse;
+if ((before = *ele == '-'))
+ ele++;
+if ((interval = readconf_readtime(ele, 0, FALSE)) < 0)
+ goto badparse;
+
+/* Remaining elements are options */
+
+while ((ele = string_nextinlist(&list, &slash, NULL, 0)))
+ if (Ustrncmp(ele, "key=", 4) == 0)
+ key = ele + 4;
+ else if (Ustrcmp(ele, "readonly") == 0)
+ mode = SEEN_READONLY;
+ else if (Ustrcmp(ele, "write") == 0)
+ mode = SEEN_WRITE;
+ else if (Ustrncmp(ele, "refresh=", 8) == 0)
+ {
+ if ((refresh = readconf_readtime(ele + 8, 0, FALSE)) < 0)
+ goto badparse;
+ }
+ else
+ goto badopt;
+
+if (!(dbm = dbfn_open(US"seen", O_RDWR|O_CREAT, &dbblock, TRUE, TRUE)))
+ {
+ HDEBUG(D_acl) debug_printf_indent("database for 'seen' not available\n");
+ *log_msgptr = US"database for 'seen' not available";
+ return DEFER;
+ }
+
+dbd = dbfn_read_with_length(dbm, key, NULL);
+now = time(NULL);
+if (dbd) /* an existing record */
+ {
+ time_t diff = now - dbd->time_stamp; /* time since the record was written */
+
+ if (before ? diff >= interval : diff < interval)
+ yield = OK;
+
+ if (mode == SEEN_READONLY)
+ { HDEBUG(D_acl) debug_printf_indent("seen db not written (readonly)\n"); }
+ else if (mode == SEEN_WRITE || !before)
+ {
+ dbd->time_stamp = now;
+ dbfn_write(dbm, key, dbd, sizeof(*dbd));
+ HDEBUG(D_acl) debug_printf_indent("seen db written (update)\n");
+ }
+ else if (diff >= refresh)
+ {
+ dbd->time_stamp = now - interval;
+ dbfn_write(dbm, key, dbd, sizeof(*dbd));
+ HDEBUG(D_acl) debug_printf_indent("seen db written (refresh)\n");
+ }
+ }
+else
+ { /* No record found, yield always FAIL */
+ if (mode != SEEN_READONLY)
+ {
+ dbdata_seen d = {.time_stamp = now};
+ dbfn_write(dbm, key, &d, sizeof(*dbd));
+ HDEBUG(D_acl) debug_printf_indent("seen db written (create)\n");
+ }
+ else
+ HDEBUG(D_acl) debug_printf_indent("seen db not written (readonly)\n");
+ }
+
+dbfn_close(dbm);
+return yield;
+
+
+badparse:
+ *log_msgptr = string_sprintf("failed to parse '%s'", arg);
+ return ERROR;
+badopt:
+ *log_msgptr = string_sprintf("unrecognised option '%s' in '%s'", ele, arg);
+ return ERROR;
+}
+
+
+
git://git.exim.org / exim.git / blobdiff