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samba-mirror/source/smbd/notify_kernel.c
Derrell Lipman 994694f7f2 r6149: Fixes bugs #2498 and 2484.
1. using smbc_getxattr() et al, one may now request all access control
   entities in the ACL without getting all other NT attributes.
2. added the ability to exclude specified attributes from the result set
   provided by smbc_getxattr() et al, when requesting all attributes,
   all NT attributes, or all DOS attributes.
3. eliminated all compiler warnings, including when --enable-developer
   compiler flags are in use.  removed -Wcast-qual flag from list, as that
   is specifically to force warnings in the case of casting away qualifiers.

Note: In the process of eliminating compiler warnings, a few nasties were
      discovered.  In the file libads/sasl.c, PRIVATE kerberos interfaces
      are being used; and in libsmb/clikrb5.c, both PRIAVE and DEPRECATED
      kerberos interfaces are being used.  Someone who knows kerberos
      should look at these and determine if there is an alternate method
      of accomplishing the task.
2007-10-10 10:56:24 -05:00

248 lines
8.2 KiB
C

/*
Unix SMB/Netbios implementation.
Version 3.0
change notify handling - linux kernel based implementation
Copyright (C) Andrew Tridgell 2000
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"
#if HAVE_KERNEL_CHANGE_NOTIFY
#define FD_PENDING_SIZE 20
static SIG_ATOMIC_T fd_pending_array[FD_PENDING_SIZE];
static SIG_ATOMIC_T signals_received;
#ifndef DN_ACCESS
#define DN_ACCESS 0x00000001 /* File accessed in directory */
#define DN_MODIFY 0x00000002 /* File modified in directory */
#define DN_CREATE 0x00000004 /* File created in directory */
#define DN_DELETE 0x00000008 /* File removed from directory */
#define DN_RENAME 0x00000010 /* File renamed in directory */
#define DN_ATTRIB 0x00000020 /* File changed attribute */
#define DN_MULTISHOT 0x80000000 /* Don't remove notifier */
#endif
#ifndef RT_SIGNAL_NOTIFY
#define RT_SIGNAL_NOTIFY (SIGRTMIN+2)
#endif
#ifndef F_SETSIG
#define F_SETSIG 10
#endif
#ifndef F_NOTIFY
#define F_NOTIFY 1026
#endif
/****************************************************************************
This is the structure to keep the information needed to
determine if a directory has changed.
*****************************************************************************/
struct change_data {
int directory_handle;
};
/****************************************************************************
The signal handler for change notify.
The Linux kernel has a bug in that we should be able to block any
further delivery of RT signals until the kernel_check_notify() function
unblocks them, but it seems that any signal mask we're setting here is
being overwritten on exit from this handler. I should create a standalone
test case for the kernel hackers. JRA.
*****************************************************************************/
static void signal_handler(int sig, siginfo_t *info, void *unused)
{
if (signals_received < FD_PENDING_SIZE - 1) {
fd_pending_array[signals_received] = (SIG_ATOMIC_T)info->si_fd;
signals_received++;
} /* Else signal is lost. */
sys_select_signal();
}
/****************************************************************************
Check if a change notify should be issued.
time non-zero means timeout check (used for hash). Ignore this (async method
where time is zero will be used instead).
*****************************************************************************/
static BOOL kernel_check_notify(connection_struct *conn, uint16 vuid, char *path, uint32 flags, void *datap, time_t t)
{
struct change_data *data = (struct change_data *)datap;
int i;
BOOL ret = False;
if (t)
return False;
BlockSignals(True, RT_SIGNAL_NOTIFY);
for (i = 0; i < signals_received; i++) {
if (data->directory_handle == (int)fd_pending_array[i]) {
DEBUG(3,("kernel_check_notify: kernel change notify on %s fd[%d]=%d (signals_received=%d)\n",
path, i, (int)fd_pending_array[i], (int)signals_received ));
close((int)fd_pending_array[i]);
fd_pending_array[i] = (SIG_ATOMIC_T)-1;
if (signals_received - i - 1) {
memmove(CONST_DISCARD(void *, &fd_pending_array[i]),
CONST_DISCARD(void *, &fd_pending_array[i+1]),
sizeof(SIG_ATOMIC_T)*(signals_received-i-1));
}
data->directory_handle = -1;
signals_received--;
ret = True;
break;
}
}
BlockSignals(False, RT_SIGNAL_NOTIFY);
return ret;
}
/****************************************************************************
Remove a change notify data structure.
*****************************************************************************/
static void kernel_remove_notify(void *datap)
{
struct change_data *data = (struct change_data *)datap;
int fd = data->directory_handle;
if (fd != -1) {
int i;
BlockSignals(True, RT_SIGNAL_NOTIFY);
for (i = 0; i < signals_received; i++) {
if (fd == (int)fd_pending_array[i]) {
fd_pending_array[i] = (SIG_ATOMIC_T)-1;
if (signals_received - i - 1) {
memmove(CONST_DISCARD(void *, &fd_pending_array[i]),
CONST_DISCARD(void *, &fd_pending_array[i+1]),
sizeof(SIG_ATOMIC_T)*(signals_received-i-1));
}
data->directory_handle = -1;
signals_received--;
break;
}
}
close(fd);
BlockSignals(False, RT_SIGNAL_NOTIFY);
}
SAFE_FREE(data);
DEBUG(3,("kernel_remove_notify: fd=%d\n", fd));
}
/****************************************************************************
Register a change notify request.
*****************************************************************************/
static void *kernel_register_notify(connection_struct *conn, char *path, uint32 flags)
{
struct change_data data;
int fd;
unsigned long kernel_flags;
fd = sys_open(path,O_RDONLY, 0);
if (fd == -1) {
DEBUG(3,("Failed to open directory %s for change notify\n", path));
return NULL;
}
if (sys_fcntl_long(fd, F_SETSIG, RT_SIGNAL_NOTIFY) == -1) {
DEBUG(3,("Failed to set signal handler for change notify\n"));
return NULL;
}
kernel_flags = DN_CREATE|DN_DELETE|DN_RENAME; /* creation/deletion changes everything! */
if (flags & FILE_NOTIFY_CHANGE_FILE) kernel_flags |= DN_MODIFY;
if (flags & FILE_NOTIFY_CHANGE_DIR_NAME) kernel_flags |= DN_RENAME|DN_DELETE;
if (flags & FILE_NOTIFY_CHANGE_ATTRIBUTES) kernel_flags |= DN_ATTRIB;
if (flags & FILE_NOTIFY_CHANGE_SIZE) kernel_flags |= DN_MODIFY;
if (flags & FILE_NOTIFY_CHANGE_LAST_WRITE) kernel_flags |= DN_MODIFY;
if (flags & FILE_NOTIFY_CHANGE_LAST_ACCESS) kernel_flags |= DN_ACCESS;
if (flags & FILE_NOTIFY_CHANGE_CREATION) kernel_flags |= DN_CREATE;
if (flags & FILE_NOTIFY_CHANGE_SECURITY) kernel_flags |= DN_ATTRIB;
if (flags & FILE_NOTIFY_CHANGE_EA) kernel_flags |= DN_ATTRIB;
if (flags & FILE_NOTIFY_CHANGE_FILE_NAME) kernel_flags |= DN_RENAME|DN_DELETE;
if (sys_fcntl_long(fd, F_NOTIFY, kernel_flags) == -1) {
DEBUG(3,("Failed to set async flag for change notify\n"));
return NULL;
}
data.directory_handle = fd;
DEBUG(3,("kernel change notify on %s (ntflags=0x%x flags=0x%x) fd=%d\n",
path, (int)flags, (int)kernel_flags, fd));
return (void *)memdup(&data, sizeof(data));
}
/****************************************************************************
See if the kernel supports change notify.
****************************************************************************/
static BOOL kernel_notify_available(void)
{
int fd, ret;
fd = open("/tmp", O_RDONLY);
if (fd == -1)
return False; /* uggh! */
ret = sys_fcntl_long(fd, F_NOTIFY, 0);
close(fd);
return ret == 0;
}
/****************************************************************************
Setup kernel based change notify.
****************************************************************************/
struct cnotify_fns *kernel_notify_init(void)
{
static struct cnotify_fns cnotify;
struct sigaction act;
ZERO_STRUCT(act);
act.sa_handler = NULL;
act.sa_sigaction = signal_handler;
act.sa_flags = SA_SIGINFO;
sigemptyset( &act.sa_mask );
if (sigaction(RT_SIGNAL_NOTIFY, &act, NULL) != 0) {
DEBUG(0,("Failed to setup RT_SIGNAL_NOTIFY handler\n"));
return NULL;
}
if (!kernel_notify_available())
return NULL;
cnotify.register_notify = kernel_register_notify;
cnotify.check_notify = kernel_check_notify;
cnotify.remove_notify = kernel_remove_notify;
cnotify.select_time = -1;
/* the signal can start off blocked due to a bug in bash */
BlockSignals(False, RT_SIGNAL_NOTIFY);
return &cnotify;
}
#else
void notify_kernel_dummy(void) {}
#endif /* HAVE_KERNEL_CHANGE_NOTIFY */