text: /* 
     Unix SMB/CIFS implementation.
     Files[] structure handling
     Copyright (C) Andrew Tridgell 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"
  
  static int real_max_open_files;
  
  #define VALID_FNUM(fnum)   (((fnum) >= 0) && ((fnum) < real_max_open_files))
  
  #define FILE_HANDLE_OFFSET 0x1000
  
  static struct bitmap *file_bmap;
  
  static files_struct *Files;
   
  /* a fsp to use when chaining */
  static files_struct *chain_fsp = NULL;
  
  static int files_used;
  
  /* A singleton cache to speed up searching by dev/inode. */
  static struct fsp_singleton_cache {
  	files_struct *fsp;
  	SMB_DEV_T dev;
  	SMB_INO_T inode;
  } fsp_fi_cache;
  
  /****************************************************************************
   Return a unique number identifying this fsp over the life of this pid.
  ****************************************************************************/
  
  static unsigned long get_gen_count(void)
  {
  	static unsigned long file_gen_counter;
  
  	if ((++file_gen_counter) == 0)
  		return ++file_gen_counter;
  	return file_gen_counter;
  }
  
  /****************************************************************************
   Find first available file slot.
  ****************************************************************************/
  
  NTSTATUS file_new(connection_struct *conn, files_struct **result)
  {
  	int i;
  	static int first_file;
  	files_struct *fsp;
  
  	/* we want to give out file handles differently on each new
  	   connection because of a common bug in MS clients where they try to
  	   reuse a file descriptor from an earlier smb connection. This code
  	   increases the chance that the errant client will get an error rather
  	   than causing corruption */
  	if (first_file == 0) {
  		first_file = (sys_getpid() ^ (int)time(NULL)) % real_max_open_files;
  	}
  
  	/* TODO: Port the id-tree implementation from Samba4 */
  
  	i = bitmap_find(file_bmap, first_file);
  	if (i == -1) {
  		DEBUG(0,("ERROR! Out of file structures\n"));
  		/* TODO: We have to unconditionally return a DOS error here,
  		 * W2k3 even returns ERRDOS/ERRnofids for ntcreate&x with
  		 * NTSTATUS negotiated */
  		return NT_STATUS_TOO_MANY_OPENED_FILES;
  	}
  
  	fsp = SMB_MALLOC_P(files_struct);
  	if (!fsp) {
  		return NT_STATUS_NO_MEMORY;
  	}
  
  	ZERO_STRUCTP(fsp);
  
  	fsp->fh = SMB_MALLOC_P(struct fd_handle);
  	if (!fsp->fh) {
  		SAFE_FREE(fsp);
  		return NT_STATUS_NO_MEMORY;
  	}
  
  	ZERO_STRUCTP(fsp->fh);
  
  	fsp->fh->ref_count = 1;
  	fsp->fh->fd = -1;
  
  	fsp->conn = conn;
  	fsp->fh->file_id = get_gen_count();
  	GetTimeOfDay(&fsp->open_time);
  
  	first_file = (i+1) % real_max_open_files;
  
  	bitmap_set(file_bmap, i);
  	files_used++;
  
  	fsp->fnum = i + FILE_HANDLE_OFFSET;
  	SMB_ASSERT(fsp->fnum < 65536);
  
  	string_set(&fsp->fsp_name,"");
  	
  	DLIST_ADD(Files, fsp);
  
  	DEBUG(5,("allocated file structure %d, fnum = %d (%d used)\n",
  		 i, fsp->fnum, files_used));
  
  	chain_fsp = fsp;
  
  	/* A new fsp invalidates a negative fsp_fi_cache. */
  	if (fsp_fi_cache.fsp == NULL) {
  		ZERO_STRUCT(fsp_fi_cache);
  	}
  
  	*result = fsp;
  	return NT_STATUS_OK;
  }
  
  /****************************************************************************
   Close all open files for a connection.
  ****************************************************************************/
  
  void file_close_conn(connection_struct *conn)
  {
  	files_struct *fsp, *next;
  	
  	for (fsp=Files;fsp;fsp=next) {
  		next = fsp->next;
  		if (fsp->conn == conn) {
  			close_file(fsp,SHUTDOWN_CLOSE); 
  		}
  	}
  }
  
  /****************************************************************************
   Close all open files for a pid and a vuid.
  ****************************************************************************/
  
  void file_close_pid(uint16 smbpid, int vuid)
  {
  	files_struct *fsp, *next;
  	
  	for (fsp=Files;fsp;fsp=next) {
  		next = fsp->next;
  		if ((fsp->file_pid == smbpid) && (fsp->vuid == vuid)) {
  			close_file(fsp,SHUTDOWN_CLOSE); 
  		}
  	}
  }
  
  /****************************************************************************
   Initialise file structures.
  ****************************************************************************/
  
  #define MAX_OPEN_FUDGEFACTOR 20
  
  void file_init(void)
  {
  	int request_max_open_files = lp_max_open_files();
  	int real_lim;
  
  	/*
  	 * Set the max_open files to be the requested
  	 * max plus a fudgefactor to allow for the extra
  	 * fd's we need such as log files etc...
  	 */
  	real_lim = set_maxfiles(request_max_open_files + MAX_OPEN_FUDGEFACTOR);
  
  	real_max_open_files = real_lim - MAX_OPEN_FUDGEFACTOR;
  
  	if (real_max_open_files + FILE_HANDLE_OFFSET + MAX_OPEN_PIPES > 65536)
  		real_max_open_files = 65536 - FILE_HANDLE_OFFSET - MAX_OPEN_PIPES;
  
  	if(real_max_open_files != request_max_open_files) {
  		DEBUG(1,("file_init: Information only: requested %d \
  open files, %d are available.\n", request_max_open_files, real_max_open_files));
  	}
  
  	SMB_ASSERT(real_max_open_files > 100);
  
  	file_bmap = bitmap_allocate(real_max_open_files);
  	
  	if (!file_bmap) {
  		exit_server("out of memory in file_init");
  	}
  	
  	/*
  	 * Ensure that pipe_handle_oppset is set correctly.
  	 */
  	set_pipe_handle_offset(real_max_open_files);
  }
  
  /****************************************************************************
   Close files open by a specified vuid.
  ****************************************************************************/
  
  void file_close_user(int vuid)
  {
  	files_struct *fsp, *next;
  
  	for (fsp=Files;fsp;fsp=next) {
  		next=fsp->next;
  		if (fsp->vuid == vuid) {
  			close_file(fsp,SHUTDOWN_CLOSE);
  		}
  	}
  }
  
  /****************************************************************************
   Debug to enumerate all open files in the smbd.
  ****************************************************************************/
  
  void file_dump_open_table(void)
  {
  	int count=0;
  	files_struct *fsp;
  
  	for (fsp=Files;fsp;fsp=fsp->next,count++) {
  		DEBUG(10,("Files[%d], fnum = %d, name %s, fd = %d, fileid = %lu, dev = %x, inode = %.0f\n",
  			count, fsp->fnum, fsp->fsp_name, fsp->fh->fd, (unsigned long)fsp->fh->file_id,
  			(unsigned int)fsp->dev, (double)fsp->inode ));
  	}
  }
  
  /****************************************************************************
   Find a fsp given a file descriptor.
  ****************************************************************************/
  
  files_struct *file_find_fd(int fd)
  {
  	int count=0;
  	files_struct *fsp;
  
  	for (fsp=Files;fsp;fsp=fsp->next,count++) {
  		if (fsp->fh->fd == fd) {
  			if (count > 10) {
  				DLIST_PROMOTE(Files, fsp);
  			}
  			return fsp;
  		}
  	}
  
  	return NULL;
  }
  
  /****************************************************************************
   Find a fsp given a device, inode and file_id.
  ****************************************************************************/
  
  files_struct *file_find_dif(SMB_DEV_T dev, SMB_INO_T inode, unsigned long file_id)
  {
  	int count=0;
  	files_struct *fsp;
  
  	for (fsp=Files;fsp;fsp=fsp->next,count++) {
  		/* We can have a fsp->fh->fd == -1 here as it could be a stat open. */
  		if (fsp->dev == dev && 
  		    fsp->inode == inode &&
  		    fsp->fh->file_id == file_id ) {
  			if (count > 10) {
  				DLIST_PROMOTE(Files, fsp);
  			}
  			/* Paranoia check. */
  			if ((fsp->fh->fd == -1) &&
  			    (fsp->oplock_type != NO_OPLOCK) &&
  			    (fsp->oplock_type != FAKE_LEVEL_II_OPLOCK)) {
  				DEBUG(0,("file_find_dif: file %s dev = %x, inode = %.0f, file_id = %u \
  oplock_type = %u is a stat open with oplock type !\n", fsp->fsp_name, (unsigned int)fsp->dev,
  						(double)fsp->inode, (unsigned int)fsp->fh->file_id,
  						(unsigned int)fsp->oplock_type ));
  				smb_panic("file_find_dif\n");
  			}
  			return fsp;
  		}
  	}
  
  	return NULL;
  }
  
  /****************************************************************************
   Check if an fsp still exists.
  ****************************************************************************/
  
  files_struct *file_find_fsp(files_struct *orig_fsp)
  {
  	files_struct *fsp;
  
  	for (fsp=Files;fsp;fsp=fsp->next) {
  		if (fsp == orig_fsp)
  			return fsp;
  	}
  
  	return NULL;
  }
  
  /****************************************************************************
   Find the first fsp given a device and inode.
   We use a singleton cache here to speed up searching from getfilepathinfo
   calls.
  ****************************************************************************/
  
  files_struct *file_find_di_first(SMB_DEV_T dev, SMB_INO_T inode)
  {
  	files_struct *fsp;
  
  	if (fsp_fi_cache.dev == dev && fsp_fi_cache.inode == inode) {
  		/* Positive or negative cache hit. */
  		return fsp_fi_cache.fsp;
  	}
  
  	fsp_fi_cache.dev = dev;
  	fsp_fi_cache.inode = inode;
  
  	for (fsp=Files;fsp;fsp=fsp->next) {
  		if ( fsp->fh->fd != -1 &&
  				fsp->dev == dev &&
  				fsp->inode == inode ) {
  			/* Setup positive cache. */
  			fsp_fi_cache.fsp = fsp;
  			return fsp;
  		}
  	}
  
  	/* Setup negative cache. */
  	fsp_fi_cache.fsp = NULL;
  	return NULL;
  }
  
  /****************************************************************************
   Find the next fsp having the same device and inode.
  ****************************************************************************/
  
  files_struct *file_find_di_next(files_struct *start_fsp)
  {
  	files_struct *fsp;
  
  	for (fsp = start_fsp->next;fsp;fsp=fsp->next) {
  		if ( fsp->fh->fd != -1 &&
  				fsp->dev == start_fsp->dev &&
  				fsp->inode == start_fsp->inode )
  			return fsp;
  	}
  
  	return NULL;
  }
  
  /****************************************************************************
   Find a fsp that is open for printing.
  ****************************************************************************/
  
  files_struct *file_find_print(void)
  {
  	files_struct *fsp;
  
  	for (fsp=Files;fsp;fsp=fsp->next) {
  		if (fsp->print_file) {
  			return fsp;
  		}
  	} 
  
  	return NULL;
  }
  
  /****************************************************************************
   Set a pending modtime across all files with a given dev/ino pair.
   Record the owner of that modtime.
  ****************************************************************************/
  
  void fsp_set_pending_modtime(files_struct *tfsp, time_t pmod)
  {
  	files_struct *fsp;
  
  	if (null_mtime(pmod)) {
  		return;
  	}
  
  	for (fsp = Files;fsp;fsp=fsp->next) {
  		if ( fsp->fh->fd != -1 &&
  				fsp->dev == tfsp->dev &&
  				fsp->inode == tfsp->inode ) {
  			fsp->pending_modtime = pmod;
  			fsp->pending_modtime_owner = False;
  		}
  	}
  
  	tfsp->pending_modtime_owner = True;
  }
  
  /****************************************************************************
   Sync open files on a connection.
  ****************************************************************************/
  
  void file_sync_all(connection_struct *conn)
  {
  	files_struct *fsp, *next;
  
  	for (fsp=Files;fsp;fsp=next) {
  		next=fsp->next;
  		if ((conn == fsp->conn) && (fsp->fh->fd != -1)) {
  			sync_file(conn, fsp, True /* write through */);
  		}
  	}
  }
  
  /****************************************************************************
   Free up a fsp.
  ****************************************************************************/
  
  void file_free(files_struct *fsp)
  {
  	DLIST_REMOVE(Files, fsp);
  
  	string_free(&fsp->fsp_name);
  
  	if (fsp->fake_file_handle) {
  		destroy_fake_file_handle(&fsp->fake_file_handle);
  	}
  
  	if (fsp->fh->ref_count == 1) {
  		SAFE_FREE(fsp->fh);
  	} else {
  		fsp->fh->ref_count--;
  	}
  
  	if (fsp->notify) {
  		notify_remove(fsp->conn->notify_ctx, fsp);
  		TALLOC_FREE(fsp->notify);
  	}
  
  	bitmap_clear(file_bmap, fsp->fnum - FILE_HANDLE_OFFSET);
  	files_used--;
  
  	DEBUG(5,("freed files structure %d (%d used)\n",
  		 fsp->fnum, files_used));
  
  	/* this is paranoia, just in case someone tries to reuse the 
  	   information */
  	ZERO_STRUCTP(fsp);
  
  	if (fsp == chain_fsp) {
  		chain_fsp = NULL;
  	}
  
  	/* Closing a file can invalidate the positive cache. */
  	if (fsp == fsp_fi_cache.fsp) {
  		ZERO_STRUCT(fsp_fi_cache);
  	}
  
  	SAFE_FREE(fsp);
  }
  
  /****************************************************************************
   Get an fsp from a 16 bit fnum.
  ****************************************************************************/
  
  files_struct *file_fnum(uint16 fnum)
  {
  	files_struct *fsp;
  	int count=0;
  
  	for (fsp=Files;fsp;fsp=fsp->next, count++) {
  		if (fsp->fnum == fnum) {
  			if (count > 10) {
  				DLIST_PROMOTE(Files, fsp);
  			}
  			return fsp;
  		}
  	}
  	return NULL;
  }
  
  /****************************************************************************
   Get an fsp from a packet given the offset of a 16 bit fnum.
  ****************************************************************************/
  
  files_struct *file_fsp(char *buf, int where)
  {
  	files_struct *fsp;
  
  	if (chain_fsp) {
  		return chain_fsp;
  	}
  
  	if (!buf) {
  		return NULL;
  	}
  
  	fsp = file_fnum(SVAL(buf, where));
  	if (fsp) {
  		chain_fsp = fsp;
  	}
  	return fsp;
  }
  
  /****************************************************************************
   Reset the chained fsp - done at the start of a packet reply.
  ****************************************************************************/
  
  void file_chain_reset(void)
  {
  	chain_fsp = NULL;
  }
  
  /****************************************************************************
   Duplicate the file handle part for a DOS or FCB open.
  ****************************************************************************/
  
  NTSTATUS dup_file_fsp(files_struct *fsp,
  				uint32 access_mask,
  				uint32 share_access,
  				uint32 create_options,
  		      		files_struct **result)
  {
  	NTSTATUS status;
  	files_struct *dup_fsp;
  
  	status = file_new(fsp->conn, &dup_fsp);
  
  	if (!NT_STATUS_IS_OK(status)) {
  		return status;
  	}
  
  	SAFE_FREE(dup_fsp->fh);
  
  	dup_fsp->fh = fsp->fh;
  	dup_fsp->fh->ref_count++;
  
  	dup_fsp->dev = fsp->dev;
  	dup_fsp->inode = fsp->inode;
  	dup_fsp->initial_allocation_size = fsp->initial_allocation_size;
  	dup_fsp->mode = fsp->mode;
  	dup_fsp->file_pid = fsp->file_pid;
  	dup_fsp->vuid = fsp->vuid;
  	dup_fsp->open_time = fsp->open_time;
  	dup_fsp->access_mask = access_mask;
  	dup_fsp->share_access = share_access;
  	dup_fsp->pending_modtime_owner = fsp->pending_modtime_owner;
  	dup_fsp->pending_modtime = fsp->pending_modtime;
  	dup_fsp->last_write_time = fsp->last_write_time;
  	dup_fsp->oplock_type = fsp->oplock_type;
  	dup_fsp->can_lock = fsp->can_lock;
  	dup_fsp->can_read = (access_mask & (FILE_READ_DATA)) ? True : False;
  	if (!CAN_WRITE(fsp->conn)) {
  		dup_fsp->can_write = False;
  	} else {
  		dup_fsp->can_write = (access_mask & (FILE_WRITE_DATA | FILE_APPEND_DATA)) ? True : False;
  	}
  	dup_fsp->print_file = fsp->print_file;
  	dup_fsp->modified = fsp->modified;
  	dup_fsp->is_directory = fsp->is_directory;
  	dup_fsp->is_stat = fsp->is_stat;
  	dup_fsp->aio_write_behind = fsp->aio_write_behind;
          string_set(&dup_fsp->fsp_name,fsp->fsp_name);
  
  	*result = dup_fsp;
  	return NT_STATUS_OK;
  }
  