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45 luk 1
 
2
/// inotify cron daemon user tables implementation
3
/**
4
 * \file usertable.cpp
5
 *
6
 * inotify cron system
7
 *
63 luk 8
 * Copyright (C) 2006, 2007 Lukas Jelinek, <lukas@aiken.cz>
45 luk 9
 *
10
 * This program is free software; you can use it, redistribute
11
 * it and/or modify it under the terms of the GNU General Public
12
 * License, version 2 (see LICENSE-GPL).
13
 *  
14
 */
15
 
16
 
17
#include <pwd.h>
18
#include <syslog.h>
19
#include <errno.h>
47 luk 20
#include <sys/wait.h>
65 luk 21
#include <unistd.h>
22
#include <grp.h>
23
#include <sys/stat.h>
45 luk 24
 
25
#include "usertable.h"
69 luk 26
#include "incroncfg.h"
45 luk 27
 
65 luk 28
#ifdef IN_DONT_FOLLOW
67 luk 29
#define DONT_FOLLOW(mask) InotifyEvent::IsType(mask, IN_DONT_FOLLOW)
65 luk 30
#else // IN_DONT_FOLLOW
67 luk 31
#define DONT_FOLLOW(mask) (false)
65 luk 32
#endif // IN_DONT_FOLLOW
45 luk 33
 
65 luk 34
 
69 luk 35
PROC_MAP UserTable::s_procMap;
47 luk 36
 
67 luk 37
extern volatile bool g_fFinish;
38
extern SUT_MAP g_ut;
47 luk 39
 
67 luk 40
 
47 luk 41
void on_proc_done(InotifyWatch* pW)
42
{
43
  pW->SetEnabled(true);
44
}
45
 
46
 
67 luk 47
EventDispatcher::EventDispatcher(int iPipeFd, Inotify* pIn, InotifyWatch* pSys, InotifyWatch* pUser)
45 luk 48
{
67 luk 49
  m_iPipeFd = iPipeFd;
50
  m_iMgmtFd = pIn->GetDescriptor();
51
  m_pIn = pIn;
52
  m_pSys = pSys;
53
  m_pUser = pUser;
54
  m_size = 0;
55
  m_pPoll = NULL;
45 luk 56
}
57
 
67 luk 58
EventDispatcher::~EventDispatcher()
45 luk 59
{
67 luk 60
  if (m_pPoll != NULL)
61
    delete[] m_pPoll;
62
}
63
 
64
bool EventDispatcher::ProcessEvents()
65
{
66
  // consume pipe events if any (and report back)
67
  bool pipe = (m_pPoll[0].revents & POLLIN);
68
  if (pipe) {
69
    char c;
70
    while (read(m_pPoll[0].fd, &c, 1) > 0) {}
71
    m_pPoll[0].revents = 0;
72
  }
73
 
74
  // process table management events if any
75
  if (m_pPoll[1].revents & POLLIN) {
76
    ProcessMgmtEvents();
77
    m_pPoll[1].revents = 0;
78
  }
45 luk 79
 
67 luk 80
  InotifyEvent evt;
45 luk 81
 
67 luk 82
  for (size_t i=2; i<m_size; i++) {
45 luk 83
 
67 luk 84
    // process events if occurred
85
    if (m_pPoll[i].revents & POLLIN) {
86
      FDUT_MAP::iterator it = m_maps.find(m_pPoll[i].fd);
87
      if (it != m_maps.end()) {
88
        Inotify* pIn = ((*it).second)->GetInotify();
89
        pIn->WaitForEvents(true);
90
 
91
        // process events for this object
92
        while (pIn->GetEvent(evt)) {
93
          ((*it).second)->OnEvent(evt);
94
        }
95
      }
96
      m_pPoll[i].revents = 0;
97
    }
98
  }
99
 
100
  return pipe;
45 luk 101
}
102
 
67 luk 103
void EventDispatcher::Register(UserTable* pTab)
45 luk 104
{
67 luk 105
  if (pTab != NULL) {
106
    Inotify* pIn = pTab->GetInotify();
107
    if (pIn != NULL) {
108
      int fd = pIn->GetDescriptor();
109
      if (fd != -1) {
110
        m_maps.insert(FDUT_MAP::value_type(fd, pTab));
111
        Rebuild();
112
      }
113
    }
114
  }
45 luk 115
}
116
 
67 luk 117
void EventDispatcher::Unregister(UserTable* pTab)
45 luk 118
{
67 luk 119
  FDUT_MAP::iterator it = m_maps.find(pTab->GetInotify()->GetDescriptor());
120
  if (it != m_maps.end()) {
55 luk 121
    m_maps.erase(it);
67 luk 122
    Rebuild();
123
  }
45 luk 124
}
67 luk 125
 
126
void EventDispatcher::Rebuild()
127
{
128
  // delete old data if exists
129
  if (m_pPoll != NULL)
130
    delete[] m_pPoll;
131
 
132
  // allocate memory
133
  m_size = m_maps.size() + 2;
134
  m_pPoll = new struct pollfd[m_size];
45 luk 135
 
67 luk 136
  // add pipe descriptor
137
  m_pPoll[0].fd = m_iPipeFd;
138
  m_pPoll[0].events = POLLIN;
139
  m_pPoll[0].revents = 0;
140
 
141
  // add table management descriptor
142
  m_pPoll[1].fd = m_iMgmtFd;
143
  m_pPoll[1].events = POLLIN;
144
  m_pPoll[1].revents = 0;
145
 
146
  // add all inotify descriptors
147
  FDUT_MAP::iterator it = m_maps.begin();
148
  for (size_t i=2; i<m_size; i++, it++) {
149
    m_pPoll[i].fd = (*it).first;
150
    m_pPoll[i].events = POLLIN;
151
    m_pPoll[i].revents = 0;
152
  }
153
}
154
 
155
void EventDispatcher::ProcessMgmtEvents()
45 luk 156
{
67 luk 157
  m_pIn->WaitForEvents(true);
158
 
159
  InotifyEvent e;
160
 
161
  while (m_pIn->GetEvent(e)) {
162
    if (e.GetWatch() == m_pSys) {
163
      if (e.IsType(IN_DELETE_SELF) || e.IsType(IN_UNMOUNT)) {
164
        syslog(LOG_CRIT, "base directory destroyed, exitting");
165
        g_fFinish = true;
166
      }
167
      else if (!e.GetName().empty()) {
69 luk 168
        SUT_MAP::iterator it = g_ut.find(IncronCfg::BuildPath(m_pSys->GetPath(), e.GetName()));
67 luk 169
        if (it != g_ut.end()) {
170
          UserTable* pUt = (*it).second;
171
          if (e.IsType(IN_CLOSE_WRITE) || e.IsType(IN_MOVED_TO)) {
172
            syslog(LOG_INFO, "system table %s changed, reloading", e.GetName().c_str());
173
            pUt->Dispose();
174
            pUt->Load();
175
          }
176
          else if (e.IsType(IN_MOVED_FROM) || e.IsType(IN_DELETE)) {
177
            syslog(LOG_INFO, "system table %s destroyed, removing", e.GetName().c_str());
178
            delete pUt;
179
            g_ut.erase(it);
180
          }
181
        }
182
        else if (e.IsType(IN_CLOSE_WRITE) || e.IsType(IN_MOVED_TO)) {
183
          syslog(LOG_INFO, "system table %s created, loading", e.GetName().c_str());
184
          UserTable* pUt = new UserTable(this, e.GetName(), true);
69 luk 185
          g_ut.insert(SUT_MAP::value_type(IncronTab::GetSystemTablePath(e.GetName()), pUt));
67 luk 186
          pUt->Load();
187
        }
188
      }
45 luk 189
    }
67 luk 190
    else if (e.GetWatch() == m_pUser) {
191
      if (e.IsType(IN_DELETE_SELF) || e.IsType(IN_UNMOUNT)) {
192
        syslog(LOG_CRIT, "base directory destroyed, exitting");
193
        g_fFinish = true;
194
      }
195
      else if (!e.GetName().empty()) {
69 luk 196
        SUT_MAP::iterator it = g_ut.find(IncronCfg::BuildPath(m_pUser->GetPath(), e.GetName()));
67 luk 197
        if (it != g_ut.end()) {
198
          UserTable* pUt = (*it).second;
199
          if (e.IsType(IN_CLOSE_WRITE) || e.IsType(IN_MOVED_TO)) {
200
            syslog(LOG_INFO, "table for user %s changed, reloading", e.GetName().c_str());
201
            pUt->Dispose();
202
            pUt->Load();
203
          }
204
          else if (e.IsType(IN_MOVED_FROM) || e.IsType(IN_DELETE)) {
205
            syslog(LOG_INFO, "table for user %s destroyed, removing",  e.GetName().c_str());
206
            delete pUt;
207
            g_ut.erase(it);
208
          }
209
        }
210
        else if (e.IsType(IN_CLOSE_WRITE) || e.IsType(IN_MOVED_TO)) {
211
          if (UserTable::CheckUser(e.GetName().c_str())) {
212
            syslog(LOG_INFO, "table for user %s created, loading", e.GetName().c_str());
213
            UserTable* pUt = new UserTable(this, e.GetName(), false);
69 luk 214
            g_ut.insert(SUT_MAP::value_type(IncronTab::GetUserTablePath(e.GetName()), pUt));
67 luk 215
            pUt->Load();
216
          }
217
        }
218
      }
45 luk 219
    }
220
  }
221
}
222
 
223
 
224
 
225
 
67 luk 226
UserTable::UserTable(EventDispatcher* pEd, const std::string& rUser, bool fSysTable)
227
: m_user(rUser),
228
  m_fSysTable(fSysTable)
45 luk 229
{
230
  m_pEd = pEd;
67 luk 231
 
232
  m_in.SetNonBlock(true);
233
  m_in.SetCloseOnExec(true);
45 luk 234
}
235
 
236
UserTable::~UserTable()
237
{
238
  Dispose();
239
}
240
 
241
void UserTable::Load()
242
{
67 luk 243
  m_tab.Load(m_fSysTable
69 luk 244
      ? IncronTab::GetSystemTablePath(m_user)
245
      : IncronTab::GetUserTablePath(m_user));
45 luk 246
 
247
  int cnt = m_tab.GetCount();
248
  for (int i=0; i<cnt; i++) {
69 luk 249
    IncronTabEntry& rE = m_tab.GetEntry(i);
45 luk 250
    InotifyWatch* pW = new InotifyWatch(rE.GetPath(), rE.GetMask());
65 luk 251
 
252
    // warning only - permissions may change later
67 luk 253
    if (!(m_fSysTable || MayAccess(rE.GetPath(), DONT_FOLLOW(rE.GetMask()))))
65 luk 254
      syslog(LOG_WARNING, "access denied on %s - events will be discarded silently", rE.GetPath().c_str());
255
 
47 luk 256
    try {
67 luk 257
      m_in.Add(pW);
47 luk 258
      m_map.insert(IWCE_MAP::value_type(pW, &rE));
259
    } catch (InotifyException e) {
67 luk 260
      if (m_fSysTable)
261
        syslog(LOG_ERR, "cannot create watch for system table %s: (%i) %s", m_user.c_str(), e.GetErrorNumber(), strerror(e.GetErrorNumber()));
262
      else
263
        syslog(LOG_ERR, "cannot create watch for user %s: (%i) %s", m_user.c_str(), e.GetErrorNumber(), strerror(e.GetErrorNumber()));
47 luk 264
      delete pW;
265
    }
45 luk 266
  }
67 luk 267
 
268
  m_pEd->Register(this);
45 luk 269
}
270
 
271
void UserTable::Dispose()
272
{
67 luk 273
  m_pEd->Unregister(this);
274
 
45 luk 275
  IWCE_MAP::iterator it = m_map.begin();
276
  while (it != m_map.end()) {
277
    InotifyWatch* pW = (*it).first;
67 luk 278
    m_in.Remove(pW);
69 luk 279
 
280
    PROC_MAP::iterator it2 = s_procMap.begin();
281
    while (it2 != s_procMap.end()) {
282
      if ((*it2).second.pWatch == pW) {
283
        PROC_MAP::iterator it3 = it2;
284
        it2++;
285
        s_procMap.erase(it3);
286
      }
287
      else {
288
        it2++;
289
      }
290
    }
291
 
45 luk 292
    delete pW;
293
    it++;
294
  }
295
 
296
  m_map.clear();
297
}
298
 
299
void UserTable::OnEvent(InotifyEvent& rEvt)
300
{
301
  InotifyWatch* pW = rEvt.GetWatch();
69 luk 302
  IncronTabEntry* pE = FindEntry(pW);
45 luk 303
 
65 luk 304
  // no entry found - this shouldn't occur
45 luk 305
  if (pE == NULL)
306
    return;
307
 
65 luk 308
  // discard event if user has no access rights to watch path
67 luk 309
  if (!(m_fSysTable || MayAccess(pW->GetPath(), DONT_FOLLOW(rEvt.GetMask()))))
65 luk 310
    return;
311
 
45 luk 312
  std::string cmd;
313
  const std::string& cs = pE->GetCmd();
314
  size_t pos = 0;
315
  size_t oldpos = 0;
316
  size_t len = cs.length();
317
  while ((pos = cs.find('$', oldpos)) != std::string::npos) {
318
    if (pos < len - 1) {
319
      size_t px = pos + 1;
320
      if (cs[px] == '$') {
321
        cmd.append(cs.substr(oldpos, pos-oldpos+1));
322
        oldpos = pos + 2;
323
      }
324
      else {
325
        cmd.append(cs.substr(oldpos, pos-oldpos));
55 luk 326
        if (cs[px] == '@') {          // base path
327
          cmd.append(pW->GetPath());
328
          oldpos = pos + 2;
329
        }
330
        else if (cs[px] == '#') {     // file name
331
          cmd.append(rEvt.GetName());
332
          oldpos = pos + 2;
333
        }
334
        else if (cs[px] == '%') {     // mask symbols
335
          std::string s;
336
          rEvt.DumpTypes(s);
337
          cmd.append(s);
338
          oldpos = pos + 2;
339
        }
340
        else if (cs[px] == '&') {     // numeric mask
341
          char* s;
342
          asprintf(&s, "%u", (unsigned) rEvt.GetMask());
343
          cmd.append(s);
344
          free(s);
345
          oldpos = pos + 2;
346
        }
347
        else {
348
          oldpos = pos + 1;
349
        }
45 luk 350
      }
351
    }
352
    else {
353
      cmd.append(cs.substr(oldpos, pos-oldpos));
354
      oldpos = pos + 1;
355
    }
356
  }    
357
  cmd.append(cs.substr(oldpos));
358
 
359
  int argc;
360
  char** argv;
361
  if (!PrepareArgs(cmd, argc, argv)) {
362
    syslog(LOG_ERR, "cannot prepare command arguments");
363
    return;
364
  }
365
 
67 luk 366
  if (m_fSysTable)
367
    syslog(LOG_INFO, "(system::%s) CMD (%s)", m_user.c_str(), cmd.c_str());
368
  else
369
    syslog(LOG_INFO, "(%s) CMD (%s)", m_user.c_str(), cmd.c_str());
45 luk 370
 
47 luk 371
  if (pE->IsNoLoop())
372
    pW->SetEnabled(false);
373
 
69 luk 374
  pid_t pid = fork();
375
  if (pid == 0) {
45 luk 376
 
67 luk 377
    // for system table
378
    if (m_fSysTable) {
379
      if (execvp(argv[0], argv) != 0) // exec failed
380
      {
381
        syslog(LOG_ERR, "cannot exec process: %s", strerror(errno));
382
        _exit(1);
383
      }
45 luk 384
    }
67 luk 385
    else {
386
      // for user table
387
      struct passwd* pwd = getpwnam(m_user.c_str());
388
      if (    pwd == NULL                 // user not found
389
          ||  setgid(pwd->pw_gid) != 0    // setting GID failed
390
          ||  setuid(pwd->pw_uid) != 0    // setting UID failed
391
          ||  execvp(argv[0], argv) != 0) // exec failed
392
      {
393
        syslog(LOG_ERR, "cannot exec process: %s", strerror(errno));
394
        _exit(1);
395
      }
396
    }
45 luk 397
  }
69 luk 398
  else if (pid > 0) {
399
    ProcData_t pd;
47 luk 400
    if (pE->IsNoLoop()) {
401
      pd.onDone = on_proc_done;
402
      pd.pWatch = pW;
403
    }
404
    else {
405
      pd.onDone = NULL;
406
      pd.pWatch = NULL;
407
    }
45 luk 408
 
69 luk 409
    s_procMap.insert(PROC_MAP::value_type(pid, pd));
45 luk 410
  }
411
  else {
47 luk 412
    if (pE->IsNoLoop())
413
      pW->SetEnabled(true);
414
 
45 luk 415
    syslog(LOG_ERR, "cannot fork process: %s", strerror(errno));
416
  }
51 luk 417
 
418
  CleanupArgs(argc, argv);
45 luk 419
}
420
 
69 luk 421
IncronTabEntry* UserTable::FindEntry(InotifyWatch* pWatch)
45 luk 422
{
423
  IWCE_MAP::iterator it = m_map.find(pWatch);
424
  if (it == m_map.end())
425
    return NULL;
426
 
427
  return (*it).second;
428
}
429
 
430
bool UserTable::PrepareArgs(const std::string& rCmd, int& argc, char**& argv)
431
{
432
  if (rCmd.empty())
433
    return false;
434
 
55 luk 435
  StringTokenizer tok(rCmd, ' ', '\\');
45 luk 436
  std::deque<std::string> args;
437
  while (tok.HasMoreTokens()) {
438
    args.push_back(tok.GetNextToken());
439
  }
440
 
441
  if (args.empty())
442
    return false;
443
 
444
  argc = (int) args.size();
445
  argv = new char*[argc+1];
446
  argv[argc] = NULL;
447
 
448
  for (int i=0; i<argc; i++) {
449
    const std::string& s = args[i];
450
    size_t len = s.length();
451
    argv[i] = new char[len+1];
452
    strcpy(argv[i], s.c_str());
453
  }
454
 
455
  return true;
456
}
457
 
51 luk 458
void UserTable::CleanupArgs(int argc, char** argv)
459
{
460
  for (int i=0; i<argc; i++) {
461
    delete[] argv[i];
462
  }
463
 
464
  delete[] argv;
465
}
466
 
47 luk 467
void UserTable::FinishDone()
468
{
69 luk 469
  pid_t res = 0;
470
  int status = 0;
471
  while ((res = waitpid(-1, &status, WNOHANG)) > 0) {
472
    PROC_MAP::iterator it = s_procMap.find(res);
473
    if (it != s_procMap.end()) {
474
      ProcData_t pd = (*it).second;
47 luk 475
      if (pd.onDone != NULL)
476
        (*pd.onDone)(pd.pWatch);
69 luk 477
      s_procMap.erase(it);
47 luk 478
    }
479
  }  
480
}
481
 
65 luk 482
bool UserTable::MayAccess(const std::string& rPath, bool fNoFollow) const
483
{
484
  // first, retrieve file permissions
485
  struct stat st;
486
  int res = fNoFollow
487
      ? lstat(rPath.c_str(), &st) // don't follow symlink
488
      : stat(rPath.c_str(), &st);
489
  if (res != 0)
490
    return false; // retrieving permissions failed
491
 
492
  // file accessible to everyone
493
  if (st.st_mode & S_IRWXO)
494
    return true;
495
 
496
  // retrieve user data
497
  struct passwd* pwd = getpwnam(m_user.c_str());
498
 
67 luk 499
  // root may always access
500
  if (pwd->pw_uid == 0)
501
    return true;
502
 
65 luk 503
  // file accesible to group
504
  if (st.st_mode & S_IRWXG) {
505
 
506
    // user's primary group
507
    if (pwd != NULL && pwd->pw_gid == st.st_gid)
508
        return true;
509
 
510
    // now check group database
511
    struct group *gr = getgrgid(st.st_gid);
512
    if (gr != NULL) {
513
      int pos = 0;
514
      const char* un;
515
      while ((un = gr->gr_mem[pos]) != NULL) {
516
        if (strcmp(un, m_user.c_str()) == 0)
517
          return true;
518
        pos++;
519
      }
520
    }
521
  }
522
 
523
  // file accessible to owner
524
  if (st.st_mode & S_IRWXU) {  
525
    if (pwd != NULL && pwd->pw_uid == st.st_uid)
526
      return true;
527
  }
528
 
529
  return false; // no access right found
530
}
47 luk 531
 
65 luk 532
 
533