src/cull_list.cpp

   1 /*       +------------------------------------+
   2  *       | Inspire Internet Relay Chat Daemon |
   3  *       +------------------------------------+
   4  *
   5  *  InspIRCd is copyright (C) 2002-2006 ChatSpike-Dev.
   6  *                       E-mail:
   7  *                <brain@chatspike.net>
   8  *                <Craig@chatspike.net>
   9  *
  10  * Written by Craig Edwards, Craig McLure, and others.
  11  * This program is free but copyrighted software; see
  12  *            the file COPYING for details.
  13  *
  14  * ---------------------------------------------------
  15  */
  16
  17 using namespace std;
  18
  19 #include "inspircd_config.h"
  20 #include "inspircd.h"
  21 #include "inspircd_io.h"
  22 #include <unistd.h>
  23 #include <fcntl.h>
  24 #include <sys/errno.h>
  25 #include <time.h>
  26 #include <string>
  27 #ifdef GCC3
  28 #include <ext/hash_map>
  29 #else
  30 #include <hash_map>
  31 #endif
  32 #include <map>
  33 #include <sstream>
  34 #include <vector>
  35 #include <deque>
  36 #include "users.h"
  37 #include "ctables.h"
  38 #include "globals.h"
  39 #include "modules.h"
  40 #include "dynamic.h"
  41 #include "wildcard.h"
  42 #include "message.h"
  43 #include "commands.h"
  44 #include "xline.h"
  45 #include "inspstring.h"
  46 #include "inspircd.h"
  47 #include "helperfuncs.h"
  48 #include "hashcomp.h"
  49 #include "typedefs.h"
  50 #include "cull_list.h"
  51
  52 extern InspIRCd* ServerInstance;
  53 extern user_hash clientlist;
  54
  55 bool CullList::IsValid(userrec* user)
  56 {
  57         time_t esignon = 0;
  58         std::map<userrec*,time_t>::iterator es = exempt.find(user);
  59         if (es != exempt.end())
  60                 esignon = es->second;
  61
  62         for (user_hash::iterator u = clientlist.begin(); u != clientlist.end(); u++)
  63         {
  64                 /*
  65                  * BUGFIX
  66                  *
  67                  * Because there is an undetermined period of time between a user existing,
  68                  * and this function being called, we have to check for the following condition:
  69                  *
  70                  * Between CullList::AddItem(u) being called, and CullList::IsValid(u) being called,
  71                  * the user with the pointer u has quit, but only to be REPLACED WITH A NEW USER WHO
  72                  * BECAUSE OF ALLOCATION RULES, HAS THE SAME MEMORY ADDRESS! To prevent this, we
  73                  * cross reference each pointer to the user's signon time, and if the signon times
  74                  * do not match, we return false here to indicate this user is NOT valid as it
  75                  * seems to differ from the pointer snapshot we got a few seconds earlier. Should
  76                  * prevent a few random crashes during netsplits.
  77                  */
  78                 if (user == u->second)
  79                         return (u->second->signon == esignon);
  80         }
  81         return false;
  82 }
  83
  84 CullItem::CullItem(userrec* u, std::string &r)
  85 {
  86         this->user = u;
  87         this->reason = r;
  88 }
  89
  90 CullItem::CullItem(userrec* u, const char* r)
  91 {
  92         this->user = u;
  93         this->reason = r;
  94 }
  95
  96 userrec* CullItem::GetUser()
  97 {
  98         return this->user;
  99 }
 100
 101 std::string CullItem::GetReason()
 102 {
 103         return this->reason;
 104 }
 105
 106 CullList::CullList()
 107 {
 108         list.clear();
 109         exempt.clear();
 110 }
 111
 112 void CullList::AddItem(userrec* user, std::string &reason)
 113 {
 114         if (exempt.find(user) == exempt.end())
 115         {
 116                 CullItem item(user,reason);
 117                 list.push_back(item);
 118                 exempt[user] = user->signon;
 119         }
 120 }
 121
 122 void CullList::AddItem(userrec* user, const char* reason)
 123 {
 124         if (exempt.find(user) == exempt.end())
 125         {
 126                 CullItem item(user,reason);
 127                 list.push_back(item);
 128                 exempt[user] = user->signon;
 129         }
 130 }
 131
 132 int CullList::Apply()
 133 {
 134         int n = 0;
 135         while (list.size())
 136         {
 137                 std::vector<CullItem>::iterator a = list.begin();
 138                 userrec* u = a->GetUser();
 139                 /* Because ServerInstance->DoOneIteration can
 140                  * take the user away from us in the middle of
 141                  * our operation, we should check to see if this
 142                  * pointer is still valid by iterating the hash.
 143                  * It's expensive, yes, but the DoOneIteration
 144                  * call stops it being horrendously bad.
 145                  */
 146                 if (IsValid(u))
 147                 {
 148                         kill_link(u,a->GetReason().c_str());
 149                         list.erase(list.begin());
 150                         /* So that huge numbers of quits dont block,
 151                          * we yield back to our mainloop every 15
 152                          * iterations.
 153                          * The DoOneIteration call basically acts
 154                          * like a software threading mechanism.
 155                          */
 156                         if (((n++) % 15) == 0)
 157                         {
 158                                 ServerInstance->DoOneIteration(false);
 159                         }
 160                 }
 161         }
 162         return n;
 163 }