/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <pthread.h>
#include <syslog.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/crypto/ioctl.h>
#include <security/cryptoki.h>
#include "kernelGlobal.h"
#include "kernelSession.h"
#include "kernelSlot.h"
#include "kernelEmulate.h"

static pthread_mutex_t delete_sessions_mutex = PTHREAD_MUTEX_INITIALIZER;

/*
 * Delete all the sessions. First, obtain the slot lock.
 * Then start to delete one session at a time.  The boolean wrapper_only
 * argument indicates that whether the caller only wants to clean up the
 * session wrappers and the object wrappers in the library.
 * - When this function is called by C_CloseAllSessions or indirectly by
 *   C_Finalize, wrapper_only is FALSE.
 * - When this function is called by cleanup_child, wrapper_only is TRUE.
 */
void
kernel_delete_all_sessions(CK_SLOT_ID slotID, boolean_t wrapper_only)
{
        kernel_session_t *session_p;
        kernel_slot_t *pslot;

        (void) pthread_mutex_lock(&delete_sessions_mutex);

        pslot = slot_table[slotID];

        /*
         * Delete all the sessions in the slot's session list.
         * The routine kernel_delete_session() updates the linked list.
         * So, we do not need to maintain the list here.
         */
        for (;;) {
                (void) pthread_mutex_lock(&pslot->sl_mutex);
                if (pslot->sl_sess_list == NULL)
                        break;

                session_p = pslot->sl_sess_list;
                /*
                 * Set SESSION_IS_CLOSING flag so any access to this
                 * session will be rejected.
                 */
                (void) pthread_mutex_lock(&session_p->session_mutex);
                if (session_p->ses_close_sync & SESSION_IS_CLOSING) {
                        (void) pthread_mutex_unlock(&session_p->session_mutex);
                        continue;
                }
                session_p->ses_close_sync |= SESSION_IS_CLOSING;
                (void) pthread_mutex_unlock(&session_p->session_mutex);

                (void) pthread_mutex_unlock(&pslot->sl_mutex);
                kernel_delete_session(slotID, session_p, B_FALSE, wrapper_only);
        }
        (void) pthread_mutex_unlock(&pslot->sl_mutex);
        (void) pthread_mutex_unlock(&delete_sessions_mutex);
}

/*
 * Create a new session struct, and add it to the slot's session list.
 *
 * This function is called by C_OpenSession(), which hold the slot lock.
 */
CK_RV
kernel_add_session(CK_SLOT_ID slotID, CK_FLAGS flags, CK_VOID_PTR pApplication,
        CK_NOTIFY notify, CK_ULONG *sessionhandle_p)
{
        CK_RV rv = CKR_OK;
        kernel_session_t *new_sp = NULL;
        crypto_open_session_t open_session;
        kernel_slot_t   *pslot;
        int r;

        /* Allocate a new session struct */
        new_sp = calloc(1, sizeof (kernel_session_t));
        if (new_sp == NULL) {
                return (CKR_HOST_MEMORY);
        }

        new_sp->magic_marker = KERNELTOKEN_SESSION_MAGIC;
        new_sp->pApplication = pApplication;
        new_sp->Notify = notify;
        new_sp->flags = flags;
        new_sp->ses_RO = (flags & CKF_RW_SESSION) ? B_FALSE : B_TRUE;
        new_sp->ses_slotid = slotID;
        new_sp->object_list = NULL;
        new_sp->ses_refcnt = 0;
        new_sp->ses_close_sync = 0;

        /* Initialize the lock for the newly created session */
        if (pthread_mutex_init(&new_sp->session_mutex, NULL) != 0) {
                free(new_sp);
                return (CKR_CANT_LOCK);
        }

        pslot = slot_table[slotID];
        open_session.os_provider_id = pslot->sl_provider_id;
        open_session.os_flags = flags;
        while ((r = ioctl(kernel_fd, CRYPTO_OPEN_SESSION, &open_session)) < 0) {
                if (errno != EINTR)
                        break;
        }
        if (r < 0) {
                rv = CKR_FUNCTION_FAILED;
        } else {
                rv = crypto2pkcs11_error_number(open_session.os_return_value);
        }

        if (rv != CKR_OK) {
                (void) pthread_mutex_destroy(&new_sp->session_mutex);
                free(new_sp);
                return (rv);
        }

        new_sp->k_session = open_session.os_session;

        (void) pthread_mutex_init(&new_sp->ses_free_mutex, NULL);
        (void) pthread_cond_init(&new_sp->ses_free_cond, NULL);

        /* Insert the new session in front of the slot's session list */
        if (pslot->sl_sess_list == NULL) {
                pslot->sl_sess_list = new_sp;
                new_sp->prev = NULL;
                new_sp->next = NULL;
        } else {
                pslot->sl_sess_list->prev = new_sp;
                new_sp->next = pslot->sl_sess_list;
                new_sp->prev = NULL;
                pslot->sl_sess_list = new_sp;
        }

        /* Type casting the address of a session struct to a session handle */
        *sessionhandle_p =  (CK_ULONG)new_sp;

        return (CKR_OK);
}

/*
 * Delete a session:
 * - Remove the session from the slot's session list.
 * - Release all the objects created by the session.
 *
 * The boolean argument slot_lock_held is used to indicate that whether
 * the caller of this function holds the slot lock or not.
 * - When called by kernel_delete_all_sessions(), which is called by
 *   C_Finalize() or C_CloseAllSessions() -- slot_lock_held = TRUE.
 * - When called by C_CloseSession() -- slot_lock_held = FALSE.
 */
void
kernel_delete_session(CK_SLOT_ID slotID, kernel_session_t *session_p,
    boolean_t slot_lock_held, boolean_t wrapper_only)
{
        crypto_session_id_t k_session;
        crypto_close_session_t close_session;
        kernel_slot_t   *pslot;
        kernel_object_t *objp;
        kernel_object_t *objp1;

        /*
         * Check to see if the caller holds the lock on the global
         * session list. If not, we need to acquire that lock in
         * order to proceed.
         */
        pslot = slot_table[slotID];
        if (!slot_lock_held) {
                /* Acquire the slot lock */
                (void) pthread_mutex_lock(&pslot->sl_mutex);
        }

        /*
         * Remove the session from the slot's session list first.
         */
        if (pslot->sl_sess_list == session_p) {
                /* Session is the first one in the list */
                if (session_p->next) {
                        pslot->sl_sess_list = session_p->next;
                        session_p->next->prev = NULL;
                } else {
                        /* Session is the only one in the list */
                        pslot->sl_sess_list = NULL;
                }
        } else {
                /* Session is not the first one in the list */
                if (session_p->next) {
                        /* Session is in the middle of the list */
                        session_p->prev->next = session_p->next;
                        session_p->next->prev = session_p->prev;
                } else {
                        /* Session is the last one in the list */
                        session_p->prev->next = NULL;
                }
        }

        if (!slot_lock_held) {
                /*
                 * If the slot lock is obtained by
                 * this function, then release that lock after
                 * removing the session from session linked list.
                 * We want the releasing of the objects of the
                 * session, and freeing of the session itself to
                 * be done without holding the slot's session list
                 * lock.
                 */
                (void) pthread_mutex_unlock(&pslot->sl_mutex);
        }

        /* Acquire the individual session lock */
        (void) pthread_mutex_lock(&session_p->session_mutex);

        /*
         * Make sure another thread hasn't freed the session.
         */
        if (session_p->magic_marker != KERNELTOKEN_SESSION_MAGIC) {
                (void) pthread_mutex_unlock(&session_p->session_mutex);
                return;
        }

        /*
         * The deletion of a session must be blocked when the session reference
         * count is not zero. This means that if the thread that is attempting
         * to close the session must wait until the prior operations on this
         * session are finished.
         *
         * Unless we are being forced to shut everything down, this only
         * happens if the library's _fini() is running not if someone
         * explicitly called C_Finalize().
         */
        (void) pthread_mutex_lock(&session_p->ses_free_mutex);

        if (wrapper_only) {
                session_p->ses_refcnt = 0;
        }

        while (session_p->ses_refcnt != 0) {
                /*
                 * We set the SESSION_REFCNT_WAITING flag before we put
                 * this closing thread in a wait state, so other non-closing
                 * operation thread will wake it up only when
                 * the session reference count becomes zero and this flag
                 * is set.
                 */
                session_p->ses_close_sync |= SESSION_REFCNT_WAITING;
                (void) pthread_mutex_unlock(&session_p->session_mutex);
                (void) pthread_cond_wait(&session_p->ses_free_cond,
                    &session_p->ses_free_mutex);
                (void) pthread_mutex_lock(&session_p->session_mutex);
        }

        session_p->ses_close_sync &= ~SESSION_REFCNT_WAITING;

        /* Mark session as no longer valid. */
        session_p->magic_marker = 0;

        (void) pthread_mutex_unlock(&session_p->ses_free_mutex);
        (void) pthread_mutex_destroy(&session_p->ses_free_mutex);
        (void) pthread_cond_destroy(&session_p->ses_free_cond);

        /*
         * Remove all the objects created in this session, waiting
         * until each object's refcnt is 0.
         */
        kernel_delete_all_objects_in_session(session_p, wrapper_only);

        /* In case application did not call Final */
        if (session_p->digest.context != NULL) {
                digest_buf_t *bufp = session_p->digest.context;

                if (bufp->buf != NULL) {
                        free_soft_ctx(get_sp(&session_p->digest), OP_DIGEST);
                        bzero(bufp->buf, bufp->indata_len);
                        free(bufp->buf);
                }
                free(bufp);
        }

        if (session_p->encrypt.context != NULL)
                free(session_p->encrypt.context);

        if (session_p->decrypt.context != NULL)
                free(session_p->decrypt.context);

        if (session_p->sign.context != NULL) {
                digest_buf_t *bufp = session_p->sign.context;

                if (bufp->buf != NULL) {
                        free_soft_ctx(get_sp(&session_p->sign), OP_SIGN);
                        bzero(bufp->buf, bufp->indata_len);
                        free(bufp->buf);
                }
                free(bufp);
        }

        if (session_p->verify.context != NULL) {
                digest_buf_t *bufp = session_p->verify.context;

                if (bufp->buf != NULL) {
                        free_soft_ctx(get_sp(&session_p->verify), OP_VERIFY);
                        bzero(bufp->buf, bufp->indata_len);
                        free(bufp->buf);
                }
                free(bufp);
        }

        k_session = session_p->k_session;

        /* Reset SESSION_IS_CLOSING flag. */
        session_p->ses_close_sync &= ~SESSION_IS_CLOSING;

        (void) pthread_mutex_unlock(&session_p->session_mutex);
        /* Destroy the individual session lock */
        (void) pthread_mutex_destroy(&session_p->session_mutex);

        if (!wrapper_only) {
                close_session.cs_session = k_session;
                while (ioctl(kernel_fd, CRYPTO_CLOSE_SESSION,
                    &close_session) < 0) {
                        if (errno != EINTR)
                                break;
                }
                /*
                 * Ignore ioctl return codes. If the library tells the kernel
                 * to close a session and the kernel says "I don't know what
                 * session you're talking about", there's not much that can be
                 * done.  All sessions in the kernel will be closed when the
                 * application exits and closes /dev/crypto.
                 */
        }
        kernel_session_delay_free(session_p);

        /*
         * If there is no more session remained in this slot, reset the slot's
         * session state to CKU_PUBLIC.  Also, clean up all the token object
         * wrappers in the library for this slot.
         */
        /* Acquire the slot lock if lock is not held */
        if (!slot_lock_held) {
                (void) pthread_mutex_lock(&pslot->sl_mutex);
        }

        if (pslot->sl_sess_list == NULL) {
                /* Reset the session auth state. */
                pslot->sl_state = CKU_PUBLIC;

                /* Clean up token object wrappers. */
                objp = pslot->sl_tobj_list;
                while (objp) {
                        objp1 = objp->next;
                        (void) pthread_mutex_destroy(&objp->object_mutex);
                        (void) kernel_object_delay_free(objp);
                        objp = objp1;
                }
                pslot->sl_tobj_list = NULL;
        }

        /* Release the slot lock if lock is not held */
        if (!slot_lock_held) {
                (void) pthread_mutex_unlock(&pslot->sl_mutex);
        }
}

/*
 * This function is used to type cast a session handle to a pointer to
 * the session struct. Also, it does the following things:
 * 1) Check to see if the session struct is tagged with a session
 *    magic number. This is to detect when an application passes
 *    a bogus session pointer.
 * 2) Acquire the locks on the designated session.
 * 3) Check to see if the session is in the closing state that another
 *    thread is performing.
 * 4) Increment the session reference count by one. This is to prevent
 *    this session from being closed by other thread.
 * 5) Release the locks on the designated session.
 */
CK_RV
handle2session(CK_SESSION_HANDLE hSession, kernel_session_t **session_p)
{
        kernel_session_t *sp = (kernel_session_t *)(hSession);
        CK_RV rv;

        if ((sp == NULL) ||
            (sp->magic_marker != KERNELTOKEN_SESSION_MAGIC)) {
                return (CKR_SESSION_HANDLE_INVALID);
        } else {
                (void) pthread_mutex_lock(&sp->session_mutex);
                if (sp->ses_close_sync & SESSION_IS_CLOSING) {
                        rv = CKR_SESSION_CLOSED;
                } else {
                        /* Increment session ref count. */
                        sp->ses_refcnt++;
                        rv = CKR_OK;
                }
                (void) pthread_mutex_unlock(&sp->session_mutex);
        }

        if (rv == CKR_OK)
                *session_p = sp;

        return (rv);
}

/*
 * This function adds the to-be-freed session to a linked list.
 * When the number of sessions queued in the linked list reaches the
 * maximum threshold MAX_SES_TO_BE_FREED, it will free the first
 * session (FIFO) in the list.
 */
void
kernel_session_delay_free(kernel_session_t *sp)
{
        kernel_session_t *tmp;

        (void) pthread_mutex_lock(&ses_delay_freed.ses_to_be_free_mutex);

        /* Add the newly deleted session at the end of the list */
        sp->next = NULL;
        if (ses_delay_freed.first == NULL) {
                ses_delay_freed.last = sp;
                ses_delay_freed.first = sp;
        } else {
                ses_delay_freed.last->next = sp;
                ses_delay_freed.last = sp;
        }

        if (++ses_delay_freed.count >= MAX_SES_TO_BE_FREED) {
                /*
                 * Free the first session in the list only if
                 * the total count reaches maximum threshold.
                 */
                ses_delay_freed.count--;
                tmp = ses_delay_freed.first->next;
                free(ses_delay_freed.first);
                ses_delay_freed.first = tmp;
        }
        (void) pthread_mutex_unlock(&ses_delay_freed.ses_to_be_free_mutex);
}

/*
 * Acquire all slots' mutexes and all their sessions' mutexes.
 * Order:
 * 1. delete_sessions_mutex
 * for each slot:
 *  2. pslot->sl_mutex
 *  for each session:
 *   3. session_p->session_mutex
 *   4. session_p->ses_free_mutex
 */
void
kernel_acquire_all_slots_mutexes()
{
        int slotID;
        kernel_slot_t *pslot;
        kernel_session_t *session_p;

        (void) pthread_mutex_lock(&delete_sessions_mutex);

        for (slotID = 0; slotID < slot_count; slotID++) {
                pslot = slot_table[slotID];
                (void) pthread_mutex_lock(&pslot->sl_mutex);

                /* Iterate through sessions acquiring all mutexes */
                session_p = pslot->sl_sess_list;
                while (session_p) {
                        struct object *objp;

                        (void) pthread_mutex_lock(&session_p->session_mutex);
                        (void) pthread_mutex_lock(&session_p->ses_free_mutex);

                        objp = session_p->object_list;
                        while (objp) {
                                (void) pthread_mutex_lock(&objp->object_mutex);
                                objp = objp->next;
                        }

                        session_p = session_p->next;
                }
        }
}

/* Release in opposite order to kernel_acquire_all_slots_mutexes(). */
void
kernel_release_all_slots_mutexes()
{
        int slotID;
        kernel_slot_t *pslot;
        kernel_session_t *session_p;

        for (slotID = 0; slotID < slot_count; slotID++) {
                pslot = slot_table[slotID];

                /* Iterate through sessions releasing all mutexes */
                session_p = pslot->sl_sess_list;
                while (session_p) {
                        struct object *objp;

                        objp = session_p->object_list;
                        while (objp) {
                                (void) pthread_mutex_unlock(
                                    &objp->object_mutex);
                                objp = objp->next;
                        }

                        (void) pthread_mutex_unlock(&session_p->ses_free_mutex);
                        (void) pthread_mutex_unlock(&session_p->session_mutex);
                        session_p = session_p->next;
                }

                (void) pthread_mutex_unlock(&pslot->sl_mutex);
        }

        (void) pthread_mutex_unlock(&delete_sessions_mutex);
}