split all the change notify code out into a separate module

smbd/notify.c. All the data structures are now private to that
module.

this is in preparation for Linux kernel support for change notify
(coming soon to a CVS tree near you)
(This used to be commit 1bb0aad4f66dbfa2d0f767ea90f926affff20b17)

1 files changed, 392 insertions, 0 deletions

diff --git a/source3/smbd/notify.c b/source3/smbd/notify.c
new file mode 100644
index 0000000000..26be17c590
--- /dev/null
+++ b/source3/smbd/notify.c
@@ -0,0 +1,392 @@
+#define OLD_NTDOMAIN 1
+/*
+   Unix SMB/Netbios implementation.
+   Version 1.9.
+   SMB NT transaction handling
+   Copyright (C) Jeremy Allison 1994-1998
+
+   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"
+
+extern int DEBUGLEVEL;
+
+/****************************************************************************
+ This is the structure to keep the information needed to
+ determine if a directory has changed.
+*****************************************************************************/
+
+typedef struct {
+  time_t modify_time; /* Info from the directory we're monitoring. */ 
+  time_t status_time; /* Info from the directory we're monitoring. */
+  time_t total_time; /* Total time of all directory entries - don't care if it wraps. */
+  unsigned int num_entries; /* Zero or the number of files in the directory. */
+} change_hash_data;
+
+/****************************************************************************
+ This is the structure to queue to implement NT change
+ notify. It consists of smb_size bytes stored from the
+ transact command (to keep the mid, tid etc around).
+ Plus the fid to examine and the time to check next.
+*****************************************************************************/
+
+typedef struct {
+  ubi_slNode msg_next;
+  files_struct *fsp;
+  connection_struct *conn;
+  uint32 flags;
+  time_t next_check_time;
+  change_hash_data change_data;
+  char request_buf[smb_size];
+} change_notify_buf;
+
+static ubi_slList change_notify_queue = { NULL, (ubi_slNodePtr)&change_notify_queue, 0};
+
+/****************************************************************************
+ Setup the common parts of the return packet and send it.
+*****************************************************************************/
+
+static void change_notify_reply_packet(char *inbuf, int error_class, uint32 error_code)
+{
+  char outbuf[smb_size+38];
+
+  memset(outbuf, '\0', sizeof(outbuf));
+  construct_reply_common(inbuf, outbuf);
+
+  /*
+   * If we're returning a 'too much in the directory changed' we need to
+   * set this is an NT error status flags. If we don't then the (probably
+   * untested) code in the NT redirector has a bug in that it doesn't re-issue
+   * the change notify.... Ah - I *love* it when I get so deeply into this I
+   * can even determine how MS failed to test stuff and why.... :-). JRA.
+   */
+
+  if(error_class == 0) /* NT Error. */
+    SSVAL(outbuf,smb_flg2, SVAL(outbuf,smb_flg2) | FLAGS2_32_BIT_ERROR_CODES);
+
+  ERROR(error_class,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);
+
+  send_smb(smbd_server_fd(),outbuf);
+}
+
+/****************************************************************************
+ Create the hash we will use to determine if the contents changed.
+*****************************************************************************/
+
+static BOOL create_directory_notify_hash( change_notify_buf *cnbp, change_hash_data *change_data)
+{
+  SMB_STRUCT_STAT st;
+  files_struct *fsp = cnbp->fsp;
+
+  memset((char *)change_data, '\0', sizeof(change_data));
+
+  /* 
+   * Store the current timestamp on the directory we are monitoring.
+   */
+
+  if(dos_stat(fsp->fsp_name, &st) < 0) {
+    DEBUG(0,("create_directory_notify_hash: Unable to stat name = %s. \
+Error was %s\n", fsp->fsp_name, strerror(errno) ));
+    return False;
+  }
+ 
+  change_data->modify_time = st.st_mtime;
+  change_data->status_time = st.st_ctime;
+
+  /*
+   * If we are to watch for changes that are only stored
+   * in inodes of files, not in the directory inode, we must
+   * scan the directory and produce a unique identifier with
+   * which we can determine if anything changed. We use the
+   * modify and change times from all the files in the
+   * directory, added together (ignoring wrapping if it's
+   * larger than the max time_t value).
+   */
+
+  if(cnbp->flags & (FILE_NOTIFY_CHANGE_SIZE|FILE_NOTIFY_CHANGE_LAST_WRITE)) {
+    pstring full_name;
+    char *p;
+    char *fname;
+    size_t remaining_len;
+    size_t fullname_len;
+    void *dp = OpenDir(cnbp->conn, fsp->fsp_name, True);
+
+    if(dp == NULL) {
+      DEBUG(0,("create_directory_notify_hash: Unable to open directory = %s. \
+Error was %s\n", fsp->fsp_name, strerror(errno) ));
+      return False;
+    }
+
+    change_data->num_entries = 0;
+
+    pstrcpy(full_name, fsp->fsp_name);
+    pstrcat(full_name, "/");
+
+    fullname_len = strlen(full_name);
+    remaining_len = sizeof(full_name) - fullname_len - 1;
+    p = &full_name[fullname_len];
+
+    while ((fname = ReadDirName(dp))) {
+      if(strequal(fname, ".") || strequal(fname, ".."))
+        continue;
+
+      change_data->num_entries++;
+      safe_strcpy( p, fname, remaining_len);
+
+      memset(&st, '\0', sizeof(st));
+
+      /*
+       * Do the stat - but ignore errors.
+       */
+
+      if(dos_stat(full_name, &st) < 0) {
+        DEBUG(5,("create_directory_notify_hash: Unable to stat content file = %s. \
+Error was %s\n", fsp->fsp_name, strerror(errno) ));
+      }
+      change_data->total_time += (st.st_mtime + st.st_ctime);
+    }
+
+    CloseDir(dp);
+  }
+
+  return True;
+}
+
+/****************************************************************************
+ Delete entries by fnum from the change notify pending queue.
+*****************************************************************************/
+
+void remove_pending_change_notify_requests_by_fid(files_struct *fsp)
+{
+  change_notify_buf *cnbp = (change_notify_buf *)ubi_slFirst( &change_notify_queue );
+  change_notify_buf *prev = NULL;
+
+  while(cnbp != NULL) {
+    if(cnbp->fsp->fnum == fsp->fnum) {
+      free((char *)ubi_slRemNext( &change_notify_queue, prev));
+      cnbp = (change_notify_buf *)(prev ? ubi_slNext(prev) : ubi_slFirst(&change_notify_queue));
+      continue;
+    }
+
+    prev = cnbp;
+    cnbp = (change_notify_buf *)ubi_slNext(cnbp);
+  }
+}
+
+/****************************************************************************
+ Delete entries by mid from the change notify pending queue. Always send reply.
+*****************************************************************************/
+
+void remove_pending_change_notify_requests_by_mid(int mid)
+{
+  change_notify_buf *cnbp = (change_notify_buf *)ubi_slFirst( &change_notify_queue );
+  change_notify_buf *prev = NULL;
+
+  while(cnbp != NULL) {
+    if(SVAL(cnbp->request_buf,smb_mid) == mid) {
+      change_notify_reply_packet(cnbp->request_buf,0,0xC0000000 |NT_STATUS_CANCELLED);
+      free((char *)ubi_slRemNext( &change_notify_queue, prev));
+      cnbp = (change_notify_buf *)(prev ? ubi_slNext(prev) : ubi_slFirst(&change_notify_queue));
+      continue;
+    }
+
+    prev = cnbp;
+    cnbp = (change_notify_buf *)ubi_slNext(cnbp);
+  }
+}
+
+/****************************************************************************
+ Delete entries by filename and cnum from the change notify pending queue.
+ Always send reply.
+*****************************************************************************/
+
+void remove_pending_change_notify_requests_by_filename(files_struct *fsp)
+{
+  change_notify_buf *cnbp = (change_notify_buf *)ubi_slFirst( &change_notify_queue );
+  change_notify_buf *prev = NULL;
+
+  while(cnbp != NULL) {
+    /*
+     * We know it refers to the same directory if the connection number and
+     * the filename are identical.
+     */
+    if((cnbp->fsp->conn == fsp->conn) && strequal(cnbp->fsp->fsp_name,fsp->fsp_name)) {
+      change_notify_reply_packet(cnbp->request_buf,0,0xC0000000 |NT_STATUS_CANCELLED);
+      free((char *)ubi_slRemNext( &change_notify_queue, prev));
+      cnbp = (change_notify_buf *)(prev ? ubi_slNext(prev) : ubi_slFirst(&change_notify_queue));
+      continue;
+    }
+
+    prev = cnbp;
+    cnbp = (change_notify_buf *)ubi_slNext(cnbp);
+  }
+}
+
+/****************************************************************************
+ Process the change notify queue. Note that this is only called as root.
+ Returns True if there are still outstanding change notify requests on the
+ queue.
+*****************************************************************************/
+
+BOOL process_pending_change_notify_queue(time_t t)
+{
+  change_notify_buf *cnbp = (change_notify_buf *)ubi_slFirst( &change_notify_queue );
+  change_notify_buf *prev = NULL;
+
+  if(cnbp == NULL)
+    return False;
+
+  if(cnbp->next_check_time >= t)
+    return True;
+
+  /*
+   * It's time to check. Go through the queue and see if
+   * the timestamps changed.
+   */
+
+  while((cnbp != NULL) && (cnbp->next_check_time <= t)) {
+    change_hash_data change_data;
+    connection_struct *conn = cnbp->conn;
+    uint16 vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID : 
+                  SVAL(cnbp->request_buf,smb_uid);
+
+    ZERO_STRUCT(change_data);
+
+    /*
+     * Ensure we don't have any old chain_fsp values
+     * sitting around....
+     */
+    chain_size = 0;
+    file_chain_reset();
+
+    if(!become_user(conn,vuid)) {
+      DEBUG(0,("process_pending_change_notify_queue: Unable to become user vuid=%d.\n",
+            vuid ));
+      /*
+       * Remove the entry and return an error to the client.
+       */
+      change_notify_reply_packet(cnbp->request_buf,ERRSRV,ERRaccess);
+      free((char *)ubi_slRemNext( &change_notify_queue, prev));
+      cnbp = (change_notify_buf *)(prev ? ubi_slNext(prev) : ubi_slFirst(&change_notify_queue));
+      continue;
+    }
+
+    if(!become_service(conn,True)) {
+	    DEBUG(0,("process_pending_change_notify_queue: Unable to become service Error was %s.\n", strerror(errno) ));
+      /*
+       * Remove the entry and return an error to the client.
+       */
+      change_notify_reply_packet(cnbp->request_buf,ERRSRV,ERRaccess);
+      free((char *)ubi_slRemNext( &change_notify_queue, prev));
+      cnbp = (change_notify_buf *)(prev ? ubi_slNext(prev) : ubi_slFirst(&change_notify_queue));
+      unbecome_user();
+      continue;
+    }
+
+    if(!create_directory_notify_hash( cnbp, &change_data)) {
+      DEBUG(0,("process_pending_change_notify_queue: Unable to create change data for \
+directory %s\n", cnbp->fsp->fsp_name ));
+      /*
+       * Remove the entry and return an error to the client.
+       */
+      change_notify_reply_packet(cnbp->request_buf,ERRSRV,ERRaccess);
+      free((char *)ubi_slRemNext( &change_notify_queue, prev));
+      cnbp = (change_notify_buf *)(prev ? ubi_slNext(prev) : ubi_slFirst(&change_notify_queue));
+      unbecome_user();
+      continue;
+    }
+
+    if(memcmp( (char *)&cnbp->change_data, (char *)&change_data, sizeof(change_data))) {
+      /*
+       * Remove the entry and return a change notify to the client.
+       */
+      DEBUG(5,("process_pending_change_notify_queue: directory name = %s changed.\n",
+            cnbp->fsp->fsp_name ));
+      change_notify_reply_packet(cnbp->request_buf,0,NT_STATUS_NOTIFY_ENUM_DIR);
+      free((char *)ubi_slRemNext( &change_notify_queue, prev));
+      cnbp = (change_notify_buf *)(prev ? ubi_slNext(prev) : ubi_slFirst(&change_notify_queue));
+      unbecome_user();
+      continue;
+    }
+
+    unbecome_user();
+
+    /*
+     * Move to the next in the list.
+     */
+    prev = cnbp;
+    cnbp = (change_notify_buf *)ubi_slNext(cnbp);
+  }
+
+  return (cnbp != NULL);
+}
+
+/****************************************************************************
+ Return true if there are pending change notifies.
+****************************************************************************/
+BOOL change_notifies_pending(void)
+{
+  change_notify_buf *cnbp = (change_notify_buf *)ubi_slFirst( &change_notify_queue );
+  return (cnbp != NULL);
+}
+
+/****************************************************************************
+   * Now queue an entry on the notify change stack. We timestamp
+   * the entry we are adding so that we know when to scan next.
+   * We only need to save smb_size bytes from this incoming packet
+   * as we will always by returning a 'read the directory yourself'
+   * error.
+****************************************************************************/
+BOOL change_notify_set(char *inbuf, files_struct *fsp, connection_struct *conn, uint32 flags)
+{
+	change_notify_buf *cnbp;
+
+	if((cnbp = (change_notify_buf *)malloc(sizeof(change_notify_buf))) == NULL) {
+		DEBUG(0,("call_nt_transact_notify_change: malloc fail !\n" ));
+		return -1;
+	}
+
+	ZERO_STRUCTP(cnbp);
+
+	memcpy(cnbp->request_buf, inbuf, smb_size);
+	cnbp->fsp = fsp;
+	cnbp->conn = conn;
+	cnbp->next_check_time = time(NULL) + lp_change_notify_timeout();
+	cnbp->flags = flags;
+	
+	if (!create_directory_notify_hash(cnbp, &cnbp->change_data)) {
+		free((char *)cnbp);
+		return False;
+	}
+	
+	/*
+	 * Adding to the tail enables us to check only
+	 * the head when scanning for change, as this entry
+	 * is forced to have the first timeout expiration.
+	 */
+	
+	ubi_slAddTail(&change_notify_queue, cnbp);
+
+	return True;
+}
+
+#undef OLD_NTDOMAIN