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samba-mirror/source3/smbd/files.c
Jeremy Allison 88b55f47b4 Move from timestamp to gen count file id's for finding oplocked files
in a tdb.
Jeremy.
(This used to be commit 058ae6b58f)
2001-10-20 21:59:34 +00:00

402 lines
10 KiB
C

/*
Unix SMB/Netbios implementation.
Version 1.9.
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;
/* a fsp to use to save when breaking an oplock. */
static files_struct *oplock_save_chain_fsp = NULL;
static int files_used;
/****************************************************************************
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.
****************************************************************************/
files_struct *file_new(connection_struct *conn)
{
int i;
static int first_file;
files_struct *fsp, *next;
/* 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;
}
i = bitmap_find(file_bmap, first_file);
if (i == -1) {
/*
* Before we give up, go through the open files
* and see if there are any files opened with a
* batch oplock. If so break the oplock and then
* re-use that entry (if it becomes closed).
* This may help as NT/95 clients tend to keep
* files batch oplocked for quite a long time
* after they have finished with them.
*/
for (fsp=Files;fsp;fsp=next) {
next=fsp->next;
if (attempt_close_oplocked_file(fsp)) {
return file_new(conn);
}
}
DEBUG(0,("ERROR! Out of file structures\n"));
unix_ERR_class = ERRSRV;
unix_ERR_code = ERRnofids;
return NULL;
}
fsp = (files_struct *)malloc(sizeof(*fsp));
if (!fsp) {
unix_ERR_class = ERRSRV;
unix_ERR_code = ERRnofids;
return NULL;
}
ZERO_STRUCTP(fsp);
fsp->fd = -1;
fsp->conn = conn;
fsp->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;
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;
return fsp;
}
/****************************************************************************
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,False);
}
}
}
/****************************************************************************
Initialise file structures.
****************************************************************************/
#define MAX_OPEN_FUDGEFACTOR 10
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 != 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));
}
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,False);
}
}
}
/****************************************************************************
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->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++) {
if (fsp->fd != -1 &&
fsp->dev == dev &&
fsp->inode == inode &&
fsp->file_id == file_id ) {
if (count > 10) {
DLIST_PROMOTE(Files, fsp);
}
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.
****************************************************************************/
files_struct *file_find_di_first(SMB_DEV_T dev, SMB_INO_T inode)
{
files_struct *fsp;
for (fsp=Files;fsp;fsp=fsp->next) {
if ( fsp->fd != -1 &&
fsp->dev == dev &&
fsp->inode == inode )
return fsp;
}
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->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;
}
/****************************************************************************
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->fd != -1)) {
sync_file(conn,fsp);
}
}
}
/****************************************************************************
Free up a fsp.
****************************************************************************/
void file_free(files_struct *fsp)
{
DLIST_REMOVE(Files, fsp);
string_free(&fsp->fsp_name);
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;
SAFE_FREE(fsp);
}
/****************************************************************************
Get a fsp from a packet given the offset of a 16 bit fnum.
****************************************************************************/
files_struct *file_fsp(char *buf, int where)
{
int fnum, count=0;
files_struct *fsp;
if (chain_fsp)
return chain_fsp;
fnum = SVAL(buf, where);
for (fsp=Files;fsp;fsp=fsp->next, count++) {
if (fsp->fnum == fnum) {
chain_fsp = fsp;
if (count > 10) {
DLIST_PROMOTE(Files, fsp);
}
return fsp;
}
}
return NULL;
}
/****************************************************************************
Reset the chained fsp - done at the start of a packet reply.
****************************************************************************/
void file_chain_reset(void)
{
chain_fsp = NULL;
}
/****************************************************************************
Save the chained fsp - done when about to do an oplock break.
****************************************************************************/
void file_chain_save(void)
{
oplock_save_chain_fsp = chain_fsp;
}
/****************************************************************************
Restore the chained fsp - done after an oplock break.
****************************************************************************/
void file_chain_restore(void)
{
chain_fsp = oplock_save_chain_fsp;
}