r21077: A step to minimize the diff later: This pulls in unmodified files from Samba4,

[Samba.git] / source3 / smbd / notify.c

/*
   Unix SMB/CIFS implementation.
   change notify handling
   Copyright (C) Andrew Tridgell 2000
   Copyright (C) Jeremy Allison 1994-1998
   Copyright (C) Volker Lendecke 2007

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include "includes.h"

static struct cnotify_fns *cnotify;
static struct notify_mid_map *notify_changes_by_mid;

/*
 * For NTCancel, we need to find the notify_change_request indexed by
 * mid. Separate list here.
 */

struct notify_mid_map {
        struct notify_mid_map *prev, *next;
        struct notify_change_request *req;
        uint16 mid;
};

static BOOL notify_marshall_changes(int num_changes,
                                    struct notify_change *changes,
                                    prs_struct *ps)
{
        int i;
        UNISTR uni_name;

        for (i=0; i<num_changes; i++) {
                struct notify_change *c = &changes[i];
                size_t namelen;
                uint32 u32_tmp; /* Temp arg to prs_uint32 to avoid
                                 * signed/unsigned issues */

                namelen = convert_string_allocate(
                        NULL, CH_UNIX, CH_UTF16LE, c->name, strlen(c->name)+1,
                        &uni_name.buffer, True);
                if ((namelen == -1) || (uni_name.buffer == NULL)) {
                        goto fail;
                }

                namelen -= 2;   /* Dump NULL termination */

                /*
                 * Offset to next entry, only if there is one
                 */

                u32_tmp = (i == num_changes-1) ? 0 : namelen + 12;
                if (!prs_uint32("offset", ps, 1, &u32_tmp)) goto fail;

                u32_tmp = c->action;
                if (!prs_uint32("action", ps, 1, &u32_tmp)) goto fail;

                u32_tmp = namelen;
                if (!prs_uint32("namelen", ps, 1, &u32_tmp)) goto fail;

                if (!prs_unistr("name", ps, 1, &uni_name)) goto fail;

                /*
                 * Not NULL terminated, decrease by the 2 UCS2 \0 chars
                 */
                prs_set_offset(ps, prs_offset(ps)-2);

                SAFE_FREE(uni_name.buffer);
        }

        return True;

 fail:
        SAFE_FREE(uni_name.buffer);
        return False;
}

/****************************************************************************
 Setup the common parts of the return packet and send it.
*****************************************************************************/

static void change_notify_reply_packet(const char *request_buf,
                                       NTSTATUS error_code)
{
        char outbuf[smb_size+38];

        memset(outbuf, '\0', sizeof(outbuf));
        construct_reply_common(request_buf, outbuf);

        ERROR_NT(error_code);

        /*
         * Seems NT needs a transact command with an error code
         * in it. This is a longer packet than a simple error.
         */
        set_message(outbuf,18,0,False);

        show_msg(outbuf);
        if (!send_smb(smbd_server_fd(),outbuf))
                exit_server_cleanly("change_notify_reply_packet: send_smb "
                                    "failed.");
}

void change_notify_reply(const char *request_buf, uint32 max_param_count,
                         int num_changes, struct notify_change *changes)
{
        char *outbuf = NULL;
        prs_struct ps;
        size_t buflen = smb_size+38+max_param_count;

        if (num_changes == -1) {
                change_notify_reply_packet(request_buf, NT_STATUS_OK);
                return;
        }

        if (!prs_init(&ps, 0, NULL, False)
            || !notify_marshall_changes(num_changes, changes, &ps)) {
                change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
                goto done;
        }

        if (prs_offset(&ps) > max_param_count) {
                /*
                 * We exceed what the client is willing to accept. Send
                 * nothing.
                 */
                change_notify_reply_packet(request_buf, NT_STATUS_OK);
                goto done;
        }

        if (!(outbuf = SMB_MALLOC_ARRAY(char, buflen))) {
                change_notify_reply_packet(request_buf, NT_STATUS_NO_MEMORY);
                goto done;
        }

        construct_reply_common(request_buf, outbuf);

        if (send_nt_replies(outbuf, buflen, NT_STATUS_OK, prs_data_p(&ps),
                            prs_offset(&ps), NULL, 0) == -1) {
                exit_server("change_notify_reply_packet: send_smb failed.");
        }

 done:
        SAFE_FREE(outbuf);
        prs_mem_free(&ps);
}

NTSTATUS change_notify_add_request(const char *inbuf, uint32 max_param_count,
                                   uint32 filter, struct files_struct *fsp)
{
        struct notify_change_request *request = NULL;
        struct notify_mid_map *map = NULL;

        if (!(request = SMB_MALLOC_P(struct notify_change_request))
            || !(map = SMB_MALLOC_P(struct notify_mid_map))) {
                SAFE_FREE(request);
                return NT_STATUS_NO_MEMORY;
        }

        request->mid_map = map;
        map->req = request;

        memcpy(request->request_buf, inbuf, sizeof(request->request_buf));
        request->max_param_count = max_param_count;
        request->filter = filter;
        request->fsp = fsp;

        request->backend_data = cnotify->notify_add(NULL, smbd_event_context(),
                                                    fsp, &request->filter);
        
        DLIST_ADD_END(fsp->notify->requests, request,
                      struct notify_change_request *);

        map->mid = SVAL(inbuf, smb_mid);
        DLIST_ADD(notify_changes_by_mid, map);

        /* Push the MID of this packet on the signing queue. */
        srv_defer_sign_response(SVAL(inbuf,smb_mid));

        return NT_STATUS_OK;
}

static void change_notify_remove_request(struct notify_change_request *remove_req)
{
        files_struct *fsp;
        struct notify_change_request *req;

        /*
         * Paranoia checks, the fsp referenced must must have the request in
         * its list of pending requests
         */

        fsp = remove_req->fsp;
        SMB_ASSERT(fsp->notify != NULL);

        for (req = fsp->notify->requests; req; req = req->next) {
                if (req == remove_req) {
                        break;
                }
        }

        if (req == NULL) {
                smb_panic("notify_req not found in fsp's requests\n");
        }

        DLIST_REMOVE(fsp->notify->requests, req);
        DLIST_REMOVE(notify_changes_by_mid, req->mid_map);
        SAFE_FREE(req->mid_map);
        TALLOC_FREE(req->backend_data);
        SAFE_FREE(req);
}

/****************************************************************************
 Delete entries by mid from the change notify pending queue. Always send reply.
*****************************************************************************/

void remove_pending_change_notify_requests_by_mid(uint16 mid)
{
        struct notify_mid_map *map;

        for (map = notify_changes_by_mid; map; map = map->next) {
                if (map->mid == mid) {
                        break;
                }
        }

        if (map == NULL) {
                return;
        }

        change_notify_reply_packet(map->req->request_buf, NT_STATUS_CANCELLED);
        change_notify_remove_request(map->req);
}

/****************************************************************************
 Delete entries by fnum from the change notify pending queue.
*****************************************************************************/

void remove_pending_change_notify_requests_by_fid(files_struct *fsp,
                                                  NTSTATUS status)
{
        if (fsp->notify == NULL) {
                return;
        }

        while (fsp->notify->requests != NULL) {
                change_notify_reply_packet(
                        fsp->notify->requests->request_buf, status);
                change_notify_remove_request(fsp->notify->requests);
        }
}

/* notify message definition

Offset  Data                    length.
0       SMB_DEV_T dev           8
8       SMB_INO_T inode         8
16      uint32 filter           4
20      uint32 action           4
24..    name
*/

#define MSG_NOTIFY_MESSAGE_SIZE 25 /* Includes at least the '\0' terminator */

struct notify_message {
        SMB_DEV_T dev;
        SMB_INO_T inode;
        uint32 filter;
        uint32 action;
        char *name;
};

static DATA_BLOB notify_message_to_buf(const struct notify_message *msg)
{
        DATA_BLOB result;
        size_t len;

        len = strlen(msg->name);

        result = data_blob(NULL, MSG_NOTIFY_MESSAGE_SIZE + len);
        if (!result.data) {
                return result;
        }

        SDEV_T_VAL(result.data, 0, msg->dev);
        SINO_T_VAL(result.data, 8, msg->inode);
        SIVAL(result.data, 16, msg->filter);
        SIVAL(result.data, 20, msg->action);
        memcpy(result.data+24, msg->name, len+1);

        return result;
}

static BOOL buf_to_notify_message(void *buf, size_t len,
                                  struct notify_message *msg)
{
        if (len < MSG_NOTIFY_MESSAGE_SIZE) {
                DEBUG(0, ("Got invalid notify message of len %d\n",
                          (int)len));
                return False;
        }

        msg->dev     = DEV_T_VAL(buf, 0);
        msg->inode   = INO_T_VAL(buf, 8);
        msg->filter  = IVAL(buf, 16);
        msg->action  = IVAL(buf, 20);
        msg->name    = ((char *)buf)+24;
        return True;
}

void notify_action(connection_struct *conn, const char *parent,
                   const char *name, uint32 filter, uint32_t action)
{
        struct share_mode_lock *lck;
        SMB_STRUCT_STAT sbuf;
        int i;
        struct notify_message msg;
        DATA_BLOB blob;

        struct process_id *pids;
        int num_pids;

        DEBUG(10, ("notify_action: parent=%s, name=%s, action=%u\n",
                   parent, name, (unsigned)action));

        if (SMB_VFS_STAT(conn, parent, &sbuf) != 0) {
                /*
                 * Not 100% critical, ignore failure
                 */
                return;
        }

        if (!(lck = get_share_mode_lock(NULL, sbuf.st_dev, sbuf.st_ino,
                                        NULL, NULL))) {
                return;
        }

        msg.dev = sbuf.st_dev;
        msg.inode = sbuf.st_ino;
        msg.filter = filter;
        msg.action = action;
        msg.name = CONST_DISCARD(char *, name);

        blob = notify_message_to_buf(&msg);
        if (blob.data == NULL) {
                DEBUG(0, ("notify_message_to_buf failed\n"));
                return;
        }

        pids = NULL;
        num_pids = 0;

        become_root_uid_only();

        for (i=0; i<lck->num_share_modes; i++) {
                struct share_mode_entry *e = &lck->share_modes[i];
                int j;
                struct process_id *tmp;

                for (j=0; j<num_pids; j++) {
                        if (procid_equal(&e->pid, &pids[j])) {
                                break;
                        }
                }

                if (j < num_pids) {
                        /*
                         * Already sent to that process, skip it
                         */
                        continue;
                }

                message_send_pid(lck->share_modes[i].pid, MSG_SMB_NOTIFY,
                                 blob.data, blob.length, True);

                if (!(tmp = TALLOC_REALLOC_ARRAY(lck, pids, struct process_id,
                                                 num_pids+1))) {
                        DEBUG(0, ("realloc failed\n"));
                        break;
                }
                pids = tmp;
                pids[num_pids] = e->pid;
                num_pids += 1;
        }

        unbecome_root_uid_only();

        data_blob_free(&blob);
        TALLOC_FREE(lck);
}

void notify_fname(connection_struct *conn, const char *path,
                  uint32 filter, uint32 action)
{
        char *parent;
        const char *name;

        if (!parent_dirname_talloc(tmp_talloc_ctx(), path, &parent, &name)) {
                return;
        }

        notify_action(conn, parent, name, filter, action);
        TALLOC_FREE(parent);
}

void notify_fsp(files_struct *fsp, uint32 action, char *name)
{
        struct notify_change *change, *changes;

        if (fsp->notify == NULL) {
                /*
                 * Nobody is waiting, don't queue
                 */
                return;
        }

        if (fsp->notify->requests != NULL) {
                /*
                 * Someone is waiting for the change, trigger the reply
                 * immediately.
                 *
                 * TODO: do we have to walk the lists of requests pending?
                 */

                struct notify_change_request *req = fsp->notify->requests;
                struct notify_change onechange;

                if (name == NULL) {
                        /*
                         * Catch-all change, possibly from notify_hash.c
                         */
                        change_notify_reply(req->request_buf,
                                            req->max_param_count,
                                            -1, NULL);
                        return;
                }

                onechange.action = action;
                onechange.name = name;

                change_notify_reply(req->request_buf, req->max_param_count,
                                    1, &onechange);
                change_notify_remove_request(req);
                return;
        }

        /*
         * Someone has triggered a notify previously, queue the change for
         * later. TODO: Limit the number of changes queued, test how filters
         * apply here. Do we have to store them?
         */

        if ((fsp->notify->num_changes > 30) || (name == NULL)) {
                /*
                 * W2k3 seems to store at most 30 changes.
                 */
                TALLOC_FREE(fsp->notify->changes);
                fsp->notify->num_changes = -1;
                return;
        }

        if (fsp->notify->num_changes == -1) {
                return;
        }

        if (!(changes = TALLOC_REALLOC_ARRAY(
                      fsp->notify, fsp->notify->changes,
                      struct notify_change, fsp->notify->num_changes+1))) {
                DEBUG(0, ("talloc_realloc failed\n"));
                return;
        }

        fsp->notify->changes = changes;

        change = &(fsp->notify->changes[fsp->notify->num_changes]);

        if (!(change->name = talloc_strdup(changes, name))) {
                DEBUG(0, ("talloc_strdup failed\n"));
                return;
        }
        change->action = action;
        fsp->notify->num_changes += 1;

        return;
}

static void notify_message_callback(int msgtype, struct process_id pid,
                                    void *buf, size_t len,
                                    void *private_data)
{
        struct notify_message msg;
        files_struct *fsp;

        if (!buf_to_notify_message(buf, len, &msg)) {
                return;
        }

        DEBUG(10, ("Received notify_message for 0x%x/%.0f: %d\n",
                   (unsigned)msg.dev, (double)msg.inode, msg.action));

        for(fsp = fsp_find_di_first(msg.dev, msg.inode); fsp;
            fsp = fsp_find_di_next(fsp)) {
                if ((fsp->notify != NULL) 
                    && (fsp->notify->requests != NULL)
                    && (fsp->notify->requests->filter & msg.filter)) {
                        notify_fsp(fsp, msg.action, msg.name);
                }
        }
}

/****************************************************************************
 Initialise the change notify subsystem.
****************************************************************************/

BOOL init_change_notify(void)
{
        cnotify = NULL;

#if HAVE_KERNEL_CHANGE_NOTIFY
        if (cnotify == NULL && lp_kernel_change_notify())
                cnotify = kernel_notify_init(smbd_event_context());
#endif
#if HAVE_FAM_CHANGE_NOTIFY
        if (cnotify == NULL && lp_fam_change_notify())
                cnotify = fam_notify_init(smbd_event_context());
#endif
        if (!cnotify) cnotify = hash_notify_init();
        
        if (!cnotify) {
                DEBUG(0,("Failed to init change notify system\n"));
                return False;
        }

        message_register(MSG_SMB_NOTIFY, notify_message_callback, NULL);

        return True;
}