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samba-mirror/source3/smbd/files.c

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/*
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"
extern int DEBUGLEVEL;
/* the only restriction is that this must be less than PIPE_HANDLE_OFFSET */
#define MAX_FNUMS 4096
#define VALID_FNUM(fnum) (((fnum) >= 0) && ((fnum) < MAX_FNUMS))
#define FILE_HANDLE_OFFSET 0x1000
static struct bitmap *file_bmap;
static struct bitmap *fd_bmap;
static files_struct *Files;
/*
* Indirection for file fd's. Needed as POSIX locking
* is based on file/process, not fd/process.
*/
static file_fd_struct *FileFd;
static int files_used, fd_ptr_used;
/****************************************************************************
find first available file slot
****************************************************************************/
files_struct *file_new(void )
{
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 = (getpid() ^ (int)time(NULL)) % MAX_FNUMS;
}
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=fsp->next) {
if (attempt_close_oplocked_file(fsp)) {
return file_new();
}
}
DEBUG(0,("ERROR! Out of file structures\n"));
return NULL;
}
fsp = (files_struct *)malloc(sizeof(*fsp));
if (!fsp) return NULL;
memset(fsp, 0, sizeof(*fsp));
first_file = (i+1) % MAX_FNUMS;
bitmap_set(file_bmap, i);
files_used++;
fsp->fnum = i + FILE_HANDLE_OFFSET;
string_init(&fsp->fsp_name,"");
/* hook into the front of the list */
if (!Files) {
Files = fsp;
} else {
Files->prev = fsp;
fsp->next = Files;
Files = fsp;
}
DEBUG(5,("allocated file structure %d (%d used)\n",
i, files_used));
return fsp;
}
/****************************************************************************
fd support routines - attempt to find an already open file by dev
and inode - increments the ref_count of the returned file_fd_struct *.
****************************************************************************/
file_fd_struct *fd_get_already_open(struct stat *sbuf)
{
file_fd_struct *fd_ptr;
if(!sbuf) return NULL;
for (fd_ptr=FileFd;fd_ptr;fd_ptr=fd_ptr->next) {
if ((fd_ptr->ref_count > 0) &&
(((uint32)sbuf->st_dev) == fd_ptr->dev) &&
(((uint32)sbuf->st_ino) == fd_ptr->inode)) {
fd_ptr->ref_count++;
DEBUG(3,("Re-used file_fd_struct dev = %x, inode = %x, ref_count = %d\n",
fd_ptr->dev, fd_ptr->inode,
fd_ptr->ref_count));
return fd_ptr;
}
}
return NULL;
}
/****************************************************************************
fd support routines - attempt to find a empty slot in the FileFd array.
Increments the ref_count of the returned entry.
****************************************************************************/
file_fd_struct *fd_get_new(void)
{
extern struct current_user current_user;
int i;
file_fd_struct *fd_ptr;
i = bitmap_find(fd_bmap, 1);
if (i == -1) {
DEBUG(0,("ERROR! Out of file_fd structures\n"));
return NULL;
}
fd_ptr = (file_fd_struct *)malloc(sizeof(*fd_ptr));
if (!fd_ptr) return NULL;
memset(fd_ptr, 0, sizeof(*fd_ptr));
fd_ptr->fdnum = i;
fd_ptr->dev = (uint32)-1;
fd_ptr->inode = (uint32)-1;
fd_ptr->fd = -1;
fd_ptr->fd_readonly = -1;
fd_ptr->fd_writeonly = -1;
fd_ptr->real_open_flags = -1;
fd_add_to_uid_cache(fd_ptr, (uid_t)current_user.uid);
fd_ptr->ref_count++;
bitmap_set(fd_bmap, i);
fd_ptr_used++;
/* hook into the front of the list */
if (!FileFd) {
FileFd = fd_ptr;
} else {
FileFd->prev = fd_ptr;
fd_ptr->next = FileFd;
FileFd = fd_ptr;
}
DEBUG(5,("allocated fd_ptr structure %d (%d used)\n",
i, fd_ptr_used));
return fd_ptr;
}
/****************************************************************************
close all open files for a connection
****************************************************************************/
void file_close_conn(connection_struct *conn)
{
files_struct *fsp;
for (fsp=Files;fsp;fsp=fsp->next) {
if (fsp->conn == conn && fsp->open) {
if (fsp->is_directory)
close_directory(fsp);
else
close_file(fsp,False);
}
}
}
/****************************************************************************
initialise file structures
****************************************************************************/
void file_init(void)
{
file_bmap = bitmap_allocate(MAX_FNUMS);
fd_bmap = bitmap_allocate(MAX_FNUMS);
if (!file_bmap || !fd_bmap) {
exit_server("out of memory in file_init");
}
#if (defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE))
{
struct rlimit rlp;
getrlimit(RLIMIT_NOFILE, &rlp);
/* Set the fd limit to be MAX_FNUMS + 10 to
* account for the extra fd we need
* as well as the log files and standard
* handles etc. */
rlp.rlim_cur = (MAX_FNUMS+10>rlp.rlim_max)?
rlp.rlim_max:MAX_FNUMS+10;
setrlimit(RLIMIT_NOFILE, &rlp);
getrlimit(RLIMIT_NOFILE, &rlp);
DEBUG(3,("Maximum number of open files per session is %d\n",
(int)rlp.rlim_cur));
}
#endif
}
/****************************************************************************
find a fsp given a fnum
****************************************************************************/
files_struct *file_fsp(int fnum)
{
files_struct *fsp;
for (fsp=Files;fsp;fsp=fsp->next) {
if (fsp->fnum == fnum) return fsp;
}
return NULL;
}
/****************************************************************************
close files open by a specified vuid
****************************************************************************/
void file_close_user(int vuid)
{
files_struct *fsp;
for (fsp=Files;fsp;fsp=fsp->next) {
if ((fsp->vuid == vuid) && fsp->open) {
if(!fsp->is_directory)
close_file(fsp,False);
else
close_directory(fsp);
}
}
}
/****************************************************************************
find a fsp given a device, inode and timevalue
****************************************************************************/
files_struct *file_find_dit(int dev, int inode, struct timeval *tval)
{
files_struct *fsp;
for (fsp=Files;fsp;fsp=fsp->next) {
if (fsp->open &&
fsp->fd_ptr->dev == dev &&
fsp->fd_ptr->inode == inode &&
fsp->open_time.tv_sec == tval->tv_sec &&
fsp->open_time.tv_usec == tval->tv_usec) {
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->open && fsp->print_file) return fsp;
}
return NULL;
}
/****************************************************************************
sync open files on a connection
****************************************************************************/
void file_sync_all(connection_struct *conn)
{
files_struct *fsp;
for (fsp=Files;fsp;fsp=fsp->next) {
if (fsp->open && conn == fsp->conn) {
sync_file(conn,fsp);
}
}
}
/****************************************************************************
free up a fd_ptr
****************************************************************************/
static void fd_ptr_free(file_fd_struct *fd_ptr)
{
if (fd_ptr == FileFd) {
FileFd = fd_ptr->next;
if (FileFd) FileFd->prev = NULL;
} else {
fd_ptr->prev->next = fd_ptr->next;
if (fd_ptr->next) fd_ptr->next->prev = fd_ptr->prev;
}
bitmap_clear(fd_bmap, fd_ptr->fdnum);
fd_ptr_used--;
DEBUG(5,("freed fd_ptr structure %d (%d used)\n",
fd_ptr->fdnum, fd_ptr_used));
/* paranoia */
memset(fd_ptr, 0, sizeof(*fd_ptr));
free(fd_ptr);
}
/****************************************************************************
free up a fsp
****************************************************************************/
void file_free(files_struct *fsp)
{
if (fsp == Files) {
Files = fsp->next;
if (Files) Files->prev = NULL;
} else {
fsp->prev->next = fsp->next;
if (fsp->next) fsp->next->prev = fsp->prev;
}
string_free(&fsp->fsp_name);
if (fsp->fd_ptr && fsp->fd_ptr->ref_count == 0) {
fd_ptr_free(fsp->fd_ptr);
}
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 */
memset(fsp, 0, sizeof(*fsp));
free(fsp);
}