--- /dev/null
+/*
+ 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(RT_SIGNAL_NOTIFY);
+}
+
+/****************************************************************************
+ 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((void *)&fd_pending_array[i], (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((void *)&fd_pending_array[i], (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_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);
+
+ void notify_kernel_dummy(void) {}
+#endif /* HAVE_KERNEL_CHANGE_NOTIFY */
projects / samba / blobdiff