Adding upstream version 3.4.23.upstream/3.4.23upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 493 insertions, 0 deletions

diff --git a/src/global/scache_multi.c b/src/global/scache_multi.c
new file mode 100644
index 0000000..7d8373d
--- /dev/null
+++ b/src/global/scache_multi.c
@@ -0,0 +1,493 @@
+/*++
+/* NAME
+/*	scache_multi 3
+/* SUMMARY
+/*	multi-session cache
+/* SYNOPSIS
+/*	#include <scache.h>
+/* DESCRIPTION
+/*	SCACHE *scache_multi_create()
+/* DESCRIPTION
+/*	This module implements an in-memory, multi-session cache.
+/*
+/*	scache_multi_create() instantiates a session cache that
+/*	stores multiple sessions.
+/* DIAGNOSTICS
+/*	Fatal error: memory allocation problem;
+/*	panic: internal consistency failure.
+/* SEE ALSO
+/*	scache(3), generic session cache API
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <unistd.h>
+#include <stddef.h>			/* offsetof() */
+#include <string.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <ring.h>
+#include <htable.h>
+#include <vstring.h>
+#include <mymalloc.h>
+#include <events.h>
+
+/*#define msg_verbose 1*/
+
+/* Global library. */
+
+#include <scache.h>
+
+/* Application-specific. */
+
+ /*
+  * SCACHE_MULTI is a derived type from the SCACHE super-class.
+  * 
+  * Each destination has an entry in the destination hash table, and each
+  * destination->endpoint binding is kept in a circular list under its
+  * destination hash table entry.
+  * 
+  * Likewise, each endpoint has an entry in the endpoint hash table, and each
+  * endpoint->session binding is kept in a circular list under its endpoint
+  * hash table entry.
+  * 
+  * We do not attempt to limit the number of destination or endpoint entries,
+  * nor do we attempt to limit the number of sessions. Doing so would require
+  * a write-through cache. Currently, the CTABLE cache module supports only
+  * read-through caching.
+  * 
+  * This is no problem because the number of cached destinations is limited by
+  * design. Sites that specify a wild-card domain pattern, and thus cache
+  * every session in recent history, may be in for a surprise.
+  */
+typedef struct {
+    SCACHE  scache[1];			/* super-class */
+    HTABLE *dest_cache;			/* destination->endpoint bindings */
+    HTABLE *endp_cache;			/* endpoint->session bindings */
+    int     sess_count;			/* number of cached sessions */
+} SCACHE_MULTI;
+
+ /*
+  * Storage for a destination or endpoint list head. Each list head knows its
+  * own hash table entry name, so that we can remove the list when it becomes
+  * empty. List items are stored in a circular list under the list head.
+  */
+typedef struct {
+    RING    ring[1];			/* circular list linkage */
+    char   *parent_key;			/* parent linkage: hash table */
+    SCACHE_MULTI *cache;		/* parent linkage: cache */
+} SCACHE_MULTI_HEAD;
+
+#define RING_TO_MULTI_HEAD(p) RING_TO_APPL((p), SCACHE_MULTI_HEAD, ring)
+
+ /*
+  * Storage for a destination->endpoint binding. This is an element in a
+  * circular list, whose list head specifies the destination.
+  */
+typedef struct {
+    RING    ring[1];			/* circular list linkage */
+    SCACHE_MULTI_HEAD *head;		/* parent linkage: list head */
+    char   *endp_label;			/* endpoint name */
+    char   *dest_prop;			/* binding properties */
+} SCACHE_MULTI_DEST;
+
+#define RING_TO_MULTI_DEST(p) RING_TO_APPL((p), SCACHE_MULTI_DEST, ring)
+
+static void scache_multi_expire_dest(int, void *);
+
+ /*
+  * Storage for an endpoint->session binding. This is an element in a
+  * circular list, whose list head specifies the endpoint.
+  */
+typedef struct {
+    RING    ring[1];			/* circular list linkage */
+    SCACHE_MULTI_HEAD *head;		/* parent linkage: list head */
+    int     fd;				/* cached session */
+    char   *endp_prop;			/* binding properties */
+} SCACHE_MULTI_ENDP;
+
+#define RING_TO_MULTI_ENDP(p) RING_TO_APPL((p), SCACHE_MULTI_ENDP, ring)
+
+static void scache_multi_expire_endp(int, void *);
+
+ /*
+  * When deleting a circular list element, are we deleting the entire
+  * circular list, or are we removing a single list element. We need this
+  * distinction to avoid a re-entrancy problem between htable_delete() and
+  * htable_free().
+  */
+#define BOTTOM_UP	1		/* one item */
+#define TOP_DOWN	2		/* whole list */
+
+/* scache_multi_drop_endp - destroy endpoint->session binding */
+
+static void scache_multi_drop_endp(SCACHE_MULTI_ENDP *endp, int direction)
+{
+    const char *myname = "scache_multi_drop_endp";
+    SCACHE_MULTI_HEAD *head;
+
+    if (msg_verbose)
+	msg_info("%s: endp_prop=%s fd=%d", myname,
+		 endp->endp_prop, endp->fd);
+
+    /*
+     * Stop the timer.
+     */
+    event_cancel_timer(scache_multi_expire_endp, (void *) endp);
+
+    /*
+     * In bottom-up mode, remove the list head from the endpoint hash when
+     * the list becomes empty. Otherwise, remove the endpoint->session
+     * binding from the list.
+     */
+    ring_detach(endp->ring);
+    head = endp->head;
+    head->cache->sess_count--;
+    if (direction == BOTTOM_UP && ring_pred(head->ring) == head->ring)
+	htable_delete(head->cache->endp_cache, head->parent_key, myfree);
+
+    /*
+     * Destroy the endpoint->session binding.
+     */
+    if (endp->fd >= 0 && close(endp->fd) != 0)
+	msg_warn("%s: close(%d): %m", myname, endp->fd);
+    myfree(endp->endp_prop);
+
+    myfree((void *) endp);
+}
+
+/* scache_multi_expire_endp - event timer call-back */
+
+static void scache_multi_expire_endp(int unused_event, void *context)
+{
+    SCACHE_MULTI_ENDP *endp = (SCACHE_MULTI_ENDP *) context;
+
+    scache_multi_drop_endp(endp, BOTTOM_UP);
+}
+
+/* scache_multi_free_endp - hash table destructor call-back */
+
+static void scache_multi_free_endp(void *ptr)
+{
+    SCACHE_MULTI_HEAD *head = (SCACHE_MULTI_HEAD *) ptr;
+    SCACHE_MULTI_ENDP *endp;
+    RING   *ring;
+
+    /*
+     * Delete each endpoint->session binding in the list, then delete the
+     * list head. Note: this changes the list, so we must iterate carefully.
+     */
+    while ((ring = ring_succ(head->ring)) != head->ring) {
+	endp = RING_TO_MULTI_ENDP(ring);
+	scache_multi_drop_endp(endp, TOP_DOWN);
+    }
+    myfree((void *) head);
+}
+
+/* scache_multi_save_endp - save endpoint->session binding */
+
+static void scache_multi_save_endp(SCACHE *scache, int ttl,
+				           const char *endp_label,
+				           const char *endp_prop, int fd)
+{
+    const char *myname = "scache_multi_save_endp";
+    SCACHE_MULTI *sp = (SCACHE_MULTI *) scache;
+    SCACHE_MULTI_HEAD *head;
+    SCACHE_MULTI_ENDP *endp;
+
+    if (ttl < 0)
+	msg_panic("%s: bad ttl: %d", myname, ttl);
+
+    /*
+     * Look up or instantiate the list head with the endpoint name.
+     */
+    if ((head = (SCACHE_MULTI_HEAD *)
+	 htable_find(sp->endp_cache, endp_label)) == 0) {
+	head = (SCACHE_MULTI_HEAD *) mymalloc(sizeof(*head));
+	ring_init(head->ring);
+	head->parent_key =
+	    htable_enter(sp->endp_cache, endp_label, (void *) head)->key;
+	head->cache = sp;
+    }
+
+    /*
+     * Add the endpoint->session binding to the list. There can never be a
+     * duplicate, because each session must have a different file descriptor.
+     */
+    endp = (SCACHE_MULTI_ENDP *) mymalloc(sizeof(*endp));
+    endp->head = head;
+    endp->fd = fd;
+    endp->endp_prop = mystrdup(endp_prop);
+    ring_prepend(head->ring, endp->ring);
+    sp->sess_count++;
+
+    /*
+     * Make sure this binding will go away eventually.
+     */
+    event_request_timer(scache_multi_expire_endp, (void *) endp, ttl);
+
+    if (msg_verbose)
+	msg_info("%s: endp_label=%s -> endp_prop=%s fd=%d",
+		 myname, endp_label, endp_prop, fd);
+}
+
+/* scache_multi_find_endp - look up session for named endpoint */
+
+static int scache_multi_find_endp(SCACHE *scache, const char *endp_label,
+				          VSTRING *endp_prop)
+{
+    const char *myname = "scache_multi_find_endp";
+    SCACHE_MULTI *sp = (SCACHE_MULTI *) scache;
+    SCACHE_MULTI_HEAD *head;
+    SCACHE_MULTI_ENDP *endp;
+    RING   *ring;
+    int     fd;
+
+    /*
+     * Look up the list head with the endpoint name.
+     */
+    if ((head = (SCACHE_MULTI_HEAD *)
+	 htable_find(sp->endp_cache, endp_label)) == 0) {
+	if (msg_verbose)
+	    msg_info("%s: no endpoint cache: endp_label=%s",
+		     myname, endp_label);
+	return (-1);
+    }
+
+    /*
+     * Use the first available session. Remove the session from the cache
+     * because we're giving it to someone else.
+     */
+    if ((ring = ring_succ(head->ring)) != head->ring) {
+	endp = RING_TO_MULTI_ENDP(ring);
+	fd = endp->fd;
+	endp->fd = -1;
+	vstring_strcpy(endp_prop, endp->endp_prop);
+	if (msg_verbose)
+	    msg_info("%s: found: endp_label=%s -> endp_prop=%s fd=%d",
+		     myname, endp_label, endp->endp_prop, fd);
+	scache_multi_drop_endp(endp, BOTTOM_UP);
+	return (fd);
+    }
+    if (msg_verbose)
+	msg_info("%s: not found: endp_label=%s", myname, endp_label);
+    return (-1);
+}
+
+/* scache_multi_drop_dest - delete destination->endpoint binding */
+
+static void scache_multi_drop_dest(SCACHE_MULTI_DEST *dest, int direction)
+{
+    const char *myname = "scache_multi_drop_dest";
+    SCACHE_MULTI_HEAD *head;
+
+    if (msg_verbose)
+	msg_info("%s: dest_prop=%s endp_label=%s",
+		 myname, dest->dest_prop, dest->endp_label);
+
+    /*
+     * Stop the timer.
+     */
+    event_cancel_timer(scache_multi_expire_dest, (void *) dest);
+
+    /*
+     * In bottom-up mode, remove the list head from the destination hash when
+     * the list becomes empty. Otherwise, remove the destination->endpoint
+     * binding from the list.
+     */
+    ring_detach(dest->ring);
+    head = dest->head;
+    if (direction == BOTTOM_UP && ring_pred(head->ring) == head->ring)
+	htable_delete(head->cache->dest_cache, head->parent_key, myfree);
+
+    /*
+     * Destroy the destination->endpoint binding.
+     */
+    myfree(dest->dest_prop);
+    myfree(dest->endp_label);
+
+    myfree((void *) dest);
+}
+
+/* scache_multi_expire_dest - event timer call-back */
+
+static void scache_multi_expire_dest(int unused_event, void *context)
+{
+    SCACHE_MULTI_DEST *dest = (SCACHE_MULTI_DEST *) context;
+
+    scache_multi_drop_dest(dest, BOTTOM_UP);
+}
+
+/* scache_multi_free_dest - hash table destructor call-back */
+
+static void scache_multi_free_dest(void *ptr)
+{
+    SCACHE_MULTI_HEAD *head = (SCACHE_MULTI_HEAD *) ptr;
+    SCACHE_MULTI_DEST *dest;
+    RING   *ring;
+
+    /*
+     * Delete each destination->endpoint binding in the list, then delete the
+     * list head. Note: this changes the list, so we must iterate carefully.
+     */
+    while ((ring = ring_succ(head->ring)) != head->ring) {
+	dest = RING_TO_MULTI_DEST(ring);
+	scache_multi_drop_dest(dest, TOP_DOWN);
+    }
+    myfree((void *) head);
+}
+
+/* scache_multi_save_dest - save destination->endpoint binding */
+
+static void scache_multi_save_dest(SCACHE *scache, int ttl,
+				           const char *dest_label,
+				           const char *dest_prop,
+				           const char *endp_label)
+{
+    const char *myname = "scache_multi_save_dest";
+    SCACHE_MULTI *sp = (SCACHE_MULTI *) scache;
+    SCACHE_MULTI_HEAD *head;
+    SCACHE_MULTI_DEST *dest;
+    RING   *ring;
+    int     refresh = 0;
+
+    if (ttl < 0)
+	msg_panic("%s: bad ttl: %d", myname, ttl);
+
+    /*
+     * Look up or instantiate the list head with the destination name.
+     */
+    if ((head = (SCACHE_MULTI_HEAD *)
+	 htable_find(sp->dest_cache, dest_label)) == 0) {
+	head = (SCACHE_MULTI_HEAD *) mymalloc(sizeof(*head));
+	ring_init(head->ring);
+	head->parent_key =
+	    htable_enter(sp->dest_cache, dest_label, (void *) head)->key;
+	head->cache = sp;
+    }
+
+    /*
+     * Look up or instantiate the destination->endpoint binding. Update the
+     * expiration time if this destination->endpoint binding already exists.
+     */
+    RING_FOREACH(ring, head->ring) {
+	dest = RING_TO_MULTI_DEST(ring);
+	if (strcmp(dest->endp_label, endp_label) == 0
+	    && strcmp(dest->dest_prop, dest_prop) == 0) {
+	    refresh = 1;
+	    break;
+	}
+    }
+    if (refresh == 0) {
+	dest = (SCACHE_MULTI_DEST *) mymalloc(sizeof(*dest));
+	dest->head = head;
+	dest->endp_label = mystrdup(endp_label);
+	dest->dest_prop = mystrdup(dest_prop);
+	ring_prepend(head->ring, dest->ring);
+    }
+
+    /*
+     * Make sure this binding will go away eventually.
+     */
+    event_request_timer(scache_multi_expire_dest, (void *) dest, ttl);
+
+    if (msg_verbose)
+	msg_info("%s: dest_label=%s -> dest_prop=%s endp_label=%s%s",
+		 myname, dest_label, dest_prop, endp_label,
+		 refresh ? " (refreshed)" : "");
+}
+
+/* scache_multi_find_dest - look up session for named destination */
+
+static int scache_multi_find_dest(SCACHE *scache, const char *dest_label,
+				          VSTRING *dest_prop,
+				          VSTRING *endp_prop)
+{
+    const char *myname = "scache_multi_find_dest";
+    SCACHE_MULTI *sp = (SCACHE_MULTI *) scache;
+    SCACHE_MULTI_HEAD *head;
+    SCACHE_MULTI_DEST *dest;
+    RING   *ring;
+    int     fd;
+
+    /*
+     * Look up the list head with the destination name.
+     */
+    if ((head = (SCACHE_MULTI_HEAD *)
+	 htable_find(sp->dest_cache, dest_label)) == 0) {
+	if (msg_verbose)
+	    msg_info("%s: no destination cache: dest_label=%s",
+		     myname, dest_label);
+	return (-1);
+    }
+
+    /*
+     * Search endpoints for the first available session.
+     */
+    RING_FOREACH(ring, head->ring) {
+	dest = RING_TO_MULTI_DEST(ring);
+	fd = scache_multi_find_endp(scache, dest->endp_label, endp_prop);
+	if (fd >= 0) {
+	    vstring_strcpy(dest_prop, dest->dest_prop);
+	    return (fd);
+	}
+    }
+    if (msg_verbose)
+	msg_info("%s: not found: dest_label=%s", myname, dest_label);
+    return (-1);
+}
+
+/* scache_multi_size - size of multi-element cache object */
+
+static void scache_multi_size(SCACHE *scache, SCACHE_SIZE *size)
+{
+    SCACHE_MULTI *sp = (SCACHE_MULTI *) scache;
+
+    size->dest_count = sp->dest_cache->used;
+    size->endp_count = sp->endp_cache->used;
+    size->sess_count = sp->sess_count;
+}
+
+/* scache_multi_free - destroy multi-element cache object */
+
+static void scache_multi_free(SCACHE *scache)
+{
+    SCACHE_MULTI *sp = (SCACHE_MULTI *) scache;
+
+    htable_free(sp->dest_cache, scache_multi_free_dest);
+    htable_free(sp->endp_cache, scache_multi_free_endp);
+
+    myfree((void *) sp);
+}
+
+/* scache_multi_create - initialize */
+
+SCACHE *scache_multi_create(void)
+{
+    SCACHE_MULTI *sp = (SCACHE_MULTI *) mymalloc(sizeof(*sp));
+
+    sp->scache->save_endp = scache_multi_save_endp;
+    sp->scache->find_endp = scache_multi_find_endp;
+    sp->scache->save_dest = scache_multi_save_dest;
+    sp->scache->find_dest = scache_multi_find_dest;
+    sp->scache->size = scache_multi_size;
+    sp->scache->free = scache_multi_free;
+
+    sp->dest_cache = htable_create(1);
+    sp->endp_cache = htable_create(1);
+    sp->sess_count = 0;
+
+    return (sp->scache);
+}