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/*
* Copyright 2003-2021 The Music Player Daemon Project
* http://www.musicpd.org
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "InotifySource.hxx"
#include "InotifyDomain.hxx"
#include "io/FileDescriptor.hxx"
#include "system/FatalError.hxx"
#include "system/Error.hxx"
#include "Log.hxx"
#include <cerrno>
#include <climits>
#include <cstdint>
#include <sys/inotify.h>
bool
InotifySource::OnSocketReady([[maybe_unused]] unsigned flags) noexcept
{
uint8_t buffer[4096];
static_assert(sizeof(buffer) >= sizeof(struct inotify_event) + NAME_MAX + 1,
"inotify buffer too small");
auto ifd = GetSocket().ToFileDescriptor();
ssize_t nbytes = ifd.Read(buffer, sizeof(buffer));
if (nbytes < 0)
FatalSystemError("Failed to read from inotify");
if (nbytes == 0)
FatalError("end of file from inotify");
const uint8_t *p = buffer, *const end = p + nbytes;
while (true) {
const size_t remaining = end - p;
const auto *event =
(const struct inotify_event *)p;
if (remaining < sizeof(*event) ||
remaining < sizeof(*event) + event->len)
break;
const char *name;
if (event->len > 0 && event->name[event->len - 1] == 0)
name = event->name;
else
name = nullptr;
callback(event->wd, event->mask, name, callback_ctx);
p += sizeof(*event) + event->len;
}
return true;
}
static FileDescriptor
InotifyInit()
{
FileDescriptor fd;
if (!fd.CreateInotify())
throw MakeErrno("inotify_init() has failed");
return fd;
}
InotifySource::InotifySource(EventLoop &_loop,
mpd_inotify_callback_t _callback, void *_ctx)
:SocketMonitor(SocketDescriptor::FromFileDescriptor(InotifyInit()),
_loop),
callback(_callback), callback_ctx(_ctx)
{
ScheduleRead();
}
int
InotifySource::Add(const char *path_fs, unsigned mask)
{
auto ifd = GetSocket().ToFileDescriptor();
int wd = inotify_add_watch(ifd.Get(), path_fs, mask);
if (wd < 0)
throw MakeErrno("inotify_add_watch() has failed");
return wd;
}
void
InotifySource::Remove(unsigned wd) noexcept
{
auto ifd = GetSocket().ToFileDescriptor();
int ret = inotify_rm_watch(ifd.Get(), wd);
if (ret < 0 && errno != EINVAL)
LogErrno(inotify_domain, "inotify_rm_watch() has failed");
/* EINVAL may happen here when the file has been deleted; the
kernel seems to auto-unregister deleted files */
}
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