source3/smbd/connection.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    connection claim routines
   5    Copyright (C) Andrew Tridgell 1998
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24
  25 extern connection_struct Connections[MAX_CONNECTIONS];
  26 extern fstring remote_machine;
  27
  28 extern int DEBUGLEVEL;
  29
  30 /****************************************************************************
  31 simple routines to do connection counting
  32 ****************************************************************************/
  33 BOOL yield_connection(int cnum,char *name,int max_connections)
  34 {
  35         struct connect_record crec;
  36         pstring fname;
  37         int fd;
  38         int mypid = getpid();
  39         int i;
  40
  41         DEBUG(3,("Yielding connection to %d %s\n",cnum,name));
  42
  43         if (max_connections <= 0)
  44                 return(True);
  45
  46         bzero(&crec,sizeof(crec));
  47
  48         pstrcpy(fname,lp_lockdir());
  49         trim_string(fname,"","/");
  50
  51         pstrcat(fname,"/");
  52         pstrcat(fname,name);
  53         pstrcat(fname,".LCK");
  54
  55         fd = open(fname,O_RDWR);
  56         if (fd == -1) {
  57                 DEBUG(2,("Couldn't open lock file %s (%s)\n",fname,strerror(errno)));
  58                 return(False);
  59         }
  60
  61         if (fcntl_lock(fd,F_SETLKW,0,1,F_WRLCK)==False) {
  62                 DEBUG(0,("ERROR: can't get lock on %s\n", fname));
  63                 return False;
  64         }
  65
  66         /* find the right spot */
  67         for (i=0;i<max_connections;i++) {
  68                 if (read(fd, &crec,sizeof(crec)) != sizeof(crec)) {
  69                         DEBUG(2,("Entry not found in lock file %s\n",fname));
  70                         if (fcntl_lock(fd,F_SETLKW,0,1,F_UNLCK)==False) {
  71                                 DEBUG(0,("ERROR: can't release lock on %s\n", fname));
  72                         }
  73                         close(fd);
  74                         return(False);
  75                 }
  76                 if (crec.pid == mypid && crec.cnum == cnum)
  77                         break;
  78         }
  79
  80         if (crec.pid != mypid || crec.cnum != cnum) {
  81                 if (fcntl_lock(fd,F_SETLKW,0,1,F_UNLCK)==False) {
  82                         DEBUG(0,("ERROR: can't release lock on %s\n", fname));
  83                 }
  84                 close(fd);
  85                 DEBUG(2,("Entry not found in lock file %s\n",fname));
  86                 return(False);
  87         }
  88
  89         bzero((void *)&crec,sizeof(crec));
  90
  91         /* remove our mark */
  92         if (lseek(fd,i*sizeof(crec),SEEK_SET) != i*sizeof(crec) ||
  93             write(fd, &crec,sizeof(crec)) != sizeof(crec)) {
  94                 DEBUG(2,("Couldn't update lock file %s (%s)\n",fname,strerror(errno)));
  95                 if (fcntl_lock(fd,F_SETLKW,0,1,F_UNLCK)==False) {
  96                         DEBUG(0,("ERROR: can't release lock on %s\n", fname));
  97                 }
  98                 close(fd);
  99                 return(False);
 100         }
 101
 102         if (fcntl_lock(fd,F_SETLKW,0,1,F_UNLCK)==False) {
 103                 DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 104         }
 105
 106         DEBUG(3,("Yield successful\n"));
 107
 108         close(fd);
 109         return(True);
 110 }
 111
 112
 113 /****************************************************************************
 114 simple routines to do connection counting
 115 ****************************************************************************/
 116 BOOL claim_connection(int cnum,char *name,int max_connections,BOOL Clear)
 117 {
 118         extern int Client;
 119         struct connect_record crec;
 120         pstring fname;
 121         int fd=-1;
 122         int i,foundi= -1;
 123         int total_recs;
 124
 125         if (max_connections <= 0)
 126                 return(True);
 127
 128         DEBUG(5,("trying claim %s %s %d\n",lp_lockdir(),name,max_connections));
 129
 130         pstrcpy(fname,lp_lockdir());
 131         trim_string(fname,"","/");
 132
 133         if (!directory_exist(fname,NULL))
 134                 mkdir(fname,0755);
 135
 136         pstrcat(fname,"/");
 137         pstrcat(fname,name);
 138         pstrcat(fname,".LCK");
 139
 140         if (!file_exist(fname,NULL)) {
 141                 fd = open(fname,O_RDWR|O_CREAT|O_EXCL, 0644);
 142         }
 143
 144         if (fd == -1) {
 145                 fd = open(fname,O_RDWR);
 146         }
 147
 148         if (fd == -1) {
 149                 DEBUG(1,("couldn't open lock file %s\n",fname));
 150                 return(False);
 151         }
 152
 153         if (fcntl_lock(fd,F_SETLKW,0,1,F_WRLCK)==False) {
 154                 DEBUG(0,("ERROR: can't get lock on %s\n", fname));
 155                 return False;
 156         }
 157
 158         total_recs = file_size(fname) / sizeof(crec);
 159
 160         /* find a free spot */
 161         for (i=0;i<max_connections;i++) {
 162                 if (i>=total_recs ||
 163                     lseek(fd,i*sizeof(crec),SEEK_SET) != i*sizeof(crec) ||
 164                     read(fd,&crec,sizeof(crec)) != sizeof(crec)) {
 165                         if (foundi < 0) foundi = i;
 166                         break;
 167                 }
 168
 169                 if (Clear && crec.pid && !process_exists(crec.pid)) {
 170                         lseek(fd,i*sizeof(crec),SEEK_SET);
 171                         bzero((void *)&crec,sizeof(crec));
 172                         write(fd, &crec,sizeof(crec));
 173                         if (foundi < 0) foundi = i;
 174                         continue;
 175                 }
 176                 if (foundi < 0 && (!crec.pid || !process_exists(crec.pid))) {
 177                         foundi=i;
 178                         if (!Clear) break;
 179                 }
 180         }
 181
 182         if (foundi < 0) {
 183                 DEBUG(3,("no free locks in %s\n",fname));
 184                 if (fcntl_lock(fd,F_SETLKW,0,1,F_UNLCK)==False) {
 185                         DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 186                 }
 187                 close(fd);
 188                 return(False);
 189         }
 190
 191         /* fill in the crec */
 192         bzero((void *)&crec,sizeof(crec));
 193         crec.magic = 0x280267;
 194         crec.pid = getpid();
 195         crec.cnum = cnum;
 196         if (cnum != -1) {
 197                 crec.uid = Connections[cnum].uid;
 198                 crec.gid = Connections[cnum].gid;
 199                 StrnCpy(crec.name,lp_servicename(SNUM(cnum)),sizeof(crec.name)-1);
 200         }
 201         crec.start = time(NULL);
 202
 203         StrnCpy(crec.machine,remote_machine,sizeof(crec.machine)-1);
 204         StrnCpy(crec.addr,client_addr(Client),sizeof(crec.addr)-1);
 205
 206         /* make our mark */
 207         if (lseek(fd,foundi*sizeof(crec),SEEK_SET) != foundi*sizeof(crec) ||
 208             write(fd, &crec,sizeof(crec)) != sizeof(crec)) {
 209                 if (fcntl_lock(fd,F_SETLKW,0,1,F_UNLCK)==False) {
 210                         DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 211                 }
 212                 close(fd);
 213                 return(False);
 214         }
 215
 216         if (fcntl_lock(fd,F_SETLKW,0,1,F_UNLCK)==False) {
 217                 DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 218         }
 219
 220         close(fd);
 221         return(True);
 222 }