1 /*
2 ** Copyright (C) 2020 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
3 **
4 ** This program is free software; you can redistribute it and/or modify it
5 ** under the terms of the GNU General Public License as published by the
6 ** Free Software Foundation; either version 3, or (at your option) any
7 ** later version.
8 **
9 ** This program is distributed in the hope that it will be useful,
10 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
11 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 ** GNU General Public License for more details.
13 **
14 ** You should have received a copy of the GNU General Public License
15 ** along with this program; if not, write to the Free Software Foundation,
16 ** Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
17 **
18 */
19 #include "mu-scanner.hh"
20
21 #include "config.h"
22
23 #include <chrono>
24 #include <mutex>
25 #include <atomic>
26 #include <thread>
27 #include <cstring>
28
29 #include <sys/types.h>
30 #include <sys/stat.h>
31 #include <unistd.h>
32
33 #include <glib.h>
34
35 #include "utils/mu-utils.hh"
36 #include "utils/mu-error.hh"
37
38 using namespace Mu;
39
40 struct Scanner::Private {
PrivateScanner::Private41 Private (const std::string& root_dir,
42 Scanner::Handler handler):
43 root_dir_{root_dir}, handler_{handler} {
44 if (!handler_)
45 throw Mu::Error{Error::Code::Internal, "missing handler"};
46 }
~PrivateScanner::Private47 ~Private() {
48 stop();
49 }
50
51 bool start();
52 bool stop();
53 bool process_dentry (const std::string& path, struct dirent *dentry, bool is_maildir);
54 bool process_dir (const std::string& path, bool is_maildir);
55
56 const std::string root_dir_;
57 const Scanner::Handler handler_;
58 std::atomic<bool> running_{};
59 std::mutex lock_;
60 };
61
62
63 static bool
is_special_dir(const struct dirent * dentry)64 is_special_dir (const struct dirent *dentry)
65 {
66 const auto d_name{dentry->d_name};
67 return d_name[0] == '\0' ||
68 (d_name[1] == '\0' && d_name[0] == '.') ||
69 (d_name[2] == '\0' && d_name[0] == '.' && d_name[1] == '.');
70 }
71
72 static bool
is_new_cur(const char * dirname)73 is_new_cur (const char *dirname)
74 {
75 if (dirname[0] == 'c' && dirname[1] == 'u' && dirname[2] == 'r' && dirname[3] == '\0')
76 return true;
77
78 if (dirname[0] == 'n' && dirname[1] == 'e' && dirname[2] == 'w' && dirname[3] == '\0')
79 return true;
80
81 return false;
82 }
83
84 bool
process_dentry(const std::string & path,struct dirent * dentry,bool is_maildir)85 Scanner::Private::process_dentry (const std::string& path, struct dirent *dentry,
86 bool is_maildir)
87 {
88 if (is_special_dir (dentry))
89 return true; // ignore.
90
91 const auto fullpath{path + "/" + dentry->d_name};
92 struct stat statbuf;
93 if (::stat(fullpath.c_str(), &statbuf) != 0) {
94 g_warning ("failed to stat %s: %s", fullpath.c_str(), g_strerror(errno));
95 return false;
96 }
97
98 if (S_ISDIR(statbuf.st_mode)) {
99 const auto new_cur = is_new_cur(dentry->d_name);
100 const auto htype = new_cur ?
101 Scanner::HandleType::EnterNewCur :
102 Scanner::HandleType::EnterDir;
103 const auto res = handler_(fullpath, &statbuf, htype);
104 if (!res)
105 return true; // skip
106
107 process_dir (fullpath, new_cur);
108
109 return handler_(fullpath, &statbuf, Scanner::HandleType::LeaveDir);
110
111 } else if (S_ISREG(statbuf.st_mode) && is_maildir)
112 return handler_(fullpath, &statbuf, Scanner::HandleType::File);
113
114 g_debug ("skip %s (neither maildir-file nor directory)", fullpath.c_str());
115 return true;
116 }
117
118
119 bool
process_dir(const std::string & path,bool is_maildir)120 Scanner::Private::process_dir (const std::string& path, bool is_maildir)
121 {
122 const auto dir = opendir (path.c_str());
123 if (G_UNLIKELY(!dir)) {
124 g_warning("failed to scan dir %s: %s", path.c_str(), g_strerror(errno));
125 return false;
126 }
127
128 // TODO: sort dentries by inode order, which makes things faster for extfs.
129 // see mu-maildir.c
130
131 while (running_) {
132 errno = 0;
133 const auto dentry{readdir(dir)};
134
135 if (G_LIKELY(dentry)) {
136 process_dentry (path, dentry, is_maildir);
137 continue;
138 }
139
140 if (errno != 0) {
141 g_warning("failed to read %s: %s", path.c_str(), g_strerror(errno));
142 continue;
143 }
144
145 break;
146 }
147 closedir (dir);
148
149 return true;
150 }
151
152 bool
start()153 Scanner::Private::start()
154 {
155 const auto& path{root_dir_};
156 if (G_UNLIKELY(path.length() > PATH_MAX)) {
157 g_warning("path too long");
158 return false;
159 }
160
161 const auto mode{F_OK | R_OK};
162 if (G_UNLIKELY(access (path.c_str(), mode) != 0)) {
163 g_warning("'%s' is not readable: %s", path.c_str(), g_strerror (errno));
164 return false;
165 }
166
167 struct stat statbuf{};
168 if (G_UNLIKELY(stat (path.c_str(), &statbuf) != 0)) {
169 g_warning("'%s' is not stat'able: %s", path.c_str(), g_strerror (errno));
170 return false;
171 }
172
173 if (G_UNLIKELY(!S_ISDIR (statbuf.st_mode))) {
174 g_warning("'%s' is not a directory", path.c_str());
175 return false;
176 }
177
178 running_ = true;
179 g_debug ("starting scan @ %s", root_dir_.c_str());
180
181 auto basename{g_path_get_basename(root_dir_.c_str())};
182 const auto is_maildir = (g_strcmp0(basename, "cur") == 0 ||
183 g_strcmp0(basename,"new") == 0);
184 g_free(basename);
185
186 const auto start{std::chrono::steady_clock::now()};
187 process_dir(root_dir_, is_maildir);
188 const auto elapsed = std::chrono::steady_clock::now() - start;
189 g_debug ("finished scan of %s in %" G_GINT64_FORMAT " ms", root_dir_.c_str(),
190 to_ms(elapsed));
191 running_ = false;
192
193 return true;
194 }
195
196 bool
stop()197 Scanner::Private::stop()
198 {
199 if (!running_)
200 return true; // nothing to do
201
202 g_debug ("stopping scan");
203 running_ = false;
204
205 return true;
206 }
207
Scanner(const std::string & root_dir,Scanner::Handler handler)208 Scanner::Scanner (const std::string& root_dir,
209 Scanner::Handler handler):
210 priv_{std::make_unique<Private>(root_dir, handler)}
211 {}
212
213 Scanner::~Scanner() = default;
214
215 bool
start()216 Scanner::start()
217 {
218 {
219 std::lock_guard<std::mutex> l(priv_->lock_);
220 if (priv_->running_)
221 return true; //nothing to do
222
223 priv_->running_ = true;
224 }
225
226 const auto res = priv_->start();
227 priv_->running_ = false;
228
229 return res;
230 }
231
232 bool
stop()233 Scanner::stop()
234 {
235 std::lock_guard<std::mutex> l(priv_->lock_);
236
237 return priv_->stop();
238 }
239
240 bool
is_running() const241 Scanner::is_running() const
242 {
243 return priv_->running_;
244 }
245