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Diffstat (limited to 'source3/smbd/notify_kernel.c')
| -rw-r--r-- | source3/smbd/notify_kernel.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/source3/smbd/notify_kernel.c b/source3/smbd/notify_kernel.c new file mode 100644 index 0000000000..19ea41e195 --- /dev/null +++ b/source3/smbd/notify_kernel.c @@ -0,0 +1,206 @@ +/* + Unix SMB/CIFS implementation. + 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 + +static VOLATILE sig_atomic_t fd_pending; +static VOLATILE sig_atomic_t signals_received; +static VOLATILE sig_atomic_t signals_processed; + +#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 34 +#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 +*****************************************************************************/ +static void signal_handler(int sig, siginfo_t *info, void *unused) +{ + BlockSignals(True, sig); + fd_pending = (sig_atomic_t)info->si_fd; + signals_received++; + 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; + + if (t) + return False; + + if (data->directory_handle != (int)fd_pending) return False; + + DEBUG(3,("kernel change notify on %s fd=%d\n", path, (int)fd_pending)); + + close((int)fd_pending); + fd_pending = (sig_atomic_t)-1; + data->directory_handle = -1; + signals_processed++; + BlockSignals(False, RT_SIGNAL_NOTIFY); + return True; +} + +/**************************************************************************** +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) { + if (fd == (int)fd_pending) { + fd_pending = (sig_atomic_t)-1; + signals_processed++; + BlockSignals(False, RT_SIGNAL_NOTIFY); + } + close(fd); + } + SAFE_FREE(data); + DEBUG(3,("removed kernel change 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 = conn->vfs_ops.open(conn, path, O_RDONLY, 0); + + if (fd == -1) { + DEBUG(3,("Failed to open directory %s for change notify\n", path)); + return NULL; + } + + if (fcntl(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 (fcntl(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 = fcntl(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; + + act.sa_handler = NULL; + act.sa_sigaction = signal_handler; + act.sa_flags = SA_SIGINFO; + 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; + + return &cnotify; +} + + +#else + void notify_kernel_dummy(void) {} +#endif /* HAVE_KERNEL_CHANGE_NOTIFY */ |