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/*
* Copyright (C) 2013 Canonical, Ltd.
*
* Authors:
* Jussi Pakkanen <jussi.pakkanen@canonical.com>
*
* This library is free software; you can redistribute it and/or modify it under
* the terms of version 3 of the GNU General Public License as published
* by the Free Software Foundation.
*
* This library 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, see <http://www.gnu.org/licenses/>.
*/
#include "SubtreeWatcher.hh"
#include "../mediascanner/MediaStore.hh"
#include "../mediascanner/MediaFile.hh"
#include "InvalidationSender.hh"
#include "../extractor/DetectedFile.hh"
#include "../extractor/MetadataExtractor.hh"
#include "../mediascanner/internal/utils.hh"
#include<sys/select.h>
#include<stdexcept>
#include<sys/inotify.h>
#include<dirent.h>
#include<sys/stat.h>
#include<unistd.h>
#include<cstring>
#include<cerrno>
#include<string>
#include<map>
#include<memory>
#include <glib.h>
#include <glib-unix.h>
using namespace std;
namespace mediascanner {
struct SubtreeWatcherPrivate {
MediaStore &store; // Hackhackhack, should be replaced with callback object or something.
MetadataExtractor &extractor;
InvalidationSender &invalidator;
int inotifyid;
// Ideally use boost::bimap or something instead of these two separate objects.
std::map<int, std::string> wd2str;
std::map<std::string, int> str2wd;
bool keep_going;
std::unique_ptr<GSource,void(*)(GSource*)> source;
SubtreeWatcherPrivate(MediaStore &store, MetadataExtractor &extractor, InvalidationSender &invalidator) :
store(store), extractor(extractor), invalidator(invalidator),
inotifyid(inotify_init()), keep_going(true),
source(g_unix_fd_source_new(inotifyid, G_IO_IN), g_source_unref) {
}
~SubtreeWatcherPrivate() {
for(auto &i : wd2str) {
inotify_rm_watch(inotifyid, i.first);
}
close(inotifyid);
}
};
static gboolean source_callback(GIOChannel *, GIOCondition, gpointer data) {
SubtreeWatcher *watcher = static_cast<SubtreeWatcher*>(data);
watcher->processEvents();
return TRUE;
}
SubtreeWatcher::SubtreeWatcher(MediaStore &store, MetadataExtractor &extractor, InvalidationSender &invalidator) {
p = new SubtreeWatcherPrivate(store, extractor, invalidator);
if(p->inotifyid == -1) {
string msg("Could not init inotify: ");
msg += strerror(errno);
delete p;
throw runtime_error(msg);
}
g_source_set_callback(p->source.get(), reinterpret_cast<GSourceFunc>(source_callback), static_cast<gpointer>(this), nullptr);
g_source_attach(p->source.get(), nullptr);
}
SubtreeWatcher::~SubtreeWatcher() {
g_source_destroy(p->source.get());
delete p;
}
void SubtreeWatcher::addDir(const string &root) {
if(root[0] != '/')
throw runtime_error("Path must be absolute.");
if(is_rootlike(root)) {
fprintf(stderr, "Directory %s looks like a top level root directory, skipping it (%s).\n",
root.c_str(), __PRETTY_FUNCTION__);
return;
}
if(has_scanblock(root)) {
fprintf(stderr, "Directory %s has a scan block file, skipping it.\n",
root.c_str());
return;
}
if(p->str2wd.find(root) != p->str2wd.end())
return;
unique_ptr<DIR, int(*)(DIR*)> dir(opendir(root.c_str()), closedir);
if(!dir) {
return;
}
int wd = inotify_add_watch(p->inotifyid, root.c_str(),
IN_CREATE | IN_DELETE_SELF | IN_DELETE | IN_CLOSE_WRITE |
IN_MOVED_FROM | IN_MOVED_TO | IN_ONLYDIR);
if(wd == -1) {
fprintf(stderr, "Could not create inotify watch object: %s\n", strerror(errno));
return; // Probably ran out of watches, keep monitoring what we can.
}
p->wd2str[wd] = root;
p->str2wd[root] = wd;
printf("Watching subdirectory %s, %ld watches in total.\n", root.c_str(),
(long)p->wd2str.size());
unique_ptr<struct dirent, void(*)(void*)> entry((dirent*)malloc(sizeof(dirent) + NAME_MAX),
free);
struct dirent *de;
while(readdir_r(dir.get(), entry.get(), &de) == 0 && de ) {
struct stat statbuf;
string fname = entry.get()->d_name;
if(fname[0] == '.') // Ignore hidden entries and also "." and "..".
continue;
string fullpath = root + "/" + fname;
lstat(fullpath.c_str(), &statbuf);
if(S_ISDIR(statbuf.st_mode)) {
addDir(fullpath);
} else if (S_ISREG(statbuf.st_mode)) {
fileAdded(fullpath);
}
}
}
bool SubtreeWatcher::removeDir(const string &abspath) {
auto it = p->str2wd.find(abspath);
if (it == p->str2wd.end()) {
return false;
}
while (it != p->str2wd.end()) {
// Stop if we're no longer dealing with subdirectories of abspath
if (it->first.compare(0, abspath.size(), abspath) != 0) {
break;
}
if (it->first.size() != abspath.size() && it->first[abspath.size()] != '/') {
break;
}
int wd = it->second;
inotify_rm_watch(p->inotifyid, wd);
p->wd2str.erase(wd);
printf("Stopped watching %s, %ld directories remain.\n",
it->first.c_str(), (long)p->wd2str.size());
it = p->str2wd.erase(it);
}
if(p->wd2str.empty())
p->keep_going = false;
p->store.removeSubtree(abspath);
return true;
}
bool SubtreeWatcher::fileAdded(const string &abspath) {
bool changed = false;
printf("New file was created: %s.\n", abspath.c_str());
try {
DetectedFile d = p->extractor.detect(abspath);
if(p->store.is_broken_file(abspath, d.etag)) {
fprintf(stderr, "Using fallback data for unscannable file %s.\n", abspath.c_str());
p->store.insert(p->extractor.fallback_extract(d));
} else if (d.etag != p->store.getETag(d.filename)) {
// Only extract and insert the file if the ETag has changed.
p->store.insert_broken_file(abspath, d.etag);
// If detection dies, insertion into broken files persists
// and the next time this file is encountered, it is skipped.
// Insert cleans broken status of the file.
p->store.insert(p->extractor.extract(d));
changed = true;
}
} catch(const exception &e) {
fprintf(stderr, "Error when adding new file: %s\n", e.what());
}
return changed;
}
void SubtreeWatcher::fileDeleted(const string &abspath) {
printf("File was deleted: %s\n", abspath.c_str());
p->store.remove(abspath);
}
void SubtreeWatcher::dirAdded(const string &abspath) {
printf("New directory was created: %s.\n", abspath.c_str());
addDir(abspath);
}
void SubtreeWatcher::dirRemoved(const string &abspath) {
printf("Subdirectory was deleted: %s.\n", abspath.c_str());
removeDir(abspath);
}
void SubtreeWatcher::processEvents() {
const int BUFSIZE=4096;
char buf[BUFSIZE];
bool changed = false;
ssize_t num_read;
num_read = read(p->inotifyid, buf, BUFSIZE);
if(num_read == 0) {
printf("Inotify returned 0.\n");
return;
}
if(num_read == -1) {
printf("Read error.\n");
return;
}
for(char *d = buf; d < buf + num_read;) {
struct inotify_event *event = (struct inotify_event *) d;
if (p->wd2str.find(event->wd) == p->wd2str.end()) {
// Ignore events for unknown watches. We may receive
// such events when a directory is removed.
d += sizeof(struct inotify_event) + event->len;
continue;
}
string directory = p->wd2str[event->wd];
string filename(event->name);
string abspath = directory + '/' + filename;
bool is_dir = false;
bool is_file = false;
struct stat statbuf;
lstat(abspath.c_str(), &statbuf);
// Remember: these are not valid in case of delete event.
is_dir = S_ISDIR(statbuf.st_mode);
is_file = S_ISREG(statbuf.st_mode);
if(event->mask & IN_CREATE) {
if(is_dir) {
dirAdded(abspath);
changed = true;
}
// Do not add files upon creation because we can't parse
// their metadata until it is fully written.
} else if((event->mask & IN_CLOSE_WRITE) || (event->mask & IN_MOVED_TO)) {
if(is_dir) {
dirAdded(abspath);
changed = true;
}
if(is_file) {
changed = fileAdded(abspath);
}
} else if((event->mask & IN_DELETE) || (event->mask & IN_MOVED_FROM)) {
if(p->str2wd.find(abspath) != p->str2wd.end()) {
dirRemoved(abspath);
changed = true;
} else {
fileDeleted(abspath);
changed = true;
}
} else if((event->mask & IN_IGNORED) || (event->mask & IN_UNMOUNT) || (event->mask & IN_DELETE_SELF)) {
removeDir(abspath);
changed = true;
}
d += sizeof(struct inotify_event) + event->len;
}
if (changed) {
p->invalidator.invalidate();
}
}
int SubtreeWatcher::getFd() const {
return p->inotifyid;
}
int SubtreeWatcher::directoryCount() const {
return (int) p->wd2str.size();
}
}
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