source/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         strcat(fname,"/");
  52         strcat(fname,name);
  53         strcat(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         struct connect_record crec;
 119         pstring fname;
 120         int fd=-1;
 121         int i,foundi= -1;
 122         int total_recs;
 123
 124         if (max_connections <= 0)
 125                 return(True);
 126
 127         DEBUG(5,("trying claim %s %s %d\n",lp_lockdir(),name,max_connections));
 128
 129         pstrcpy(fname,lp_lockdir());
 130         trim_string(fname,"","/");
 131
 132         if (!directory_exist(fname,NULL))
 133                 mkdir(fname,0755);
 134
 135         strcat(fname,"/");
 136         strcat(fname,name);
 137         strcat(fname,".LCK");
 138
 139         if (!file_exist(fname,NULL)) {
 140                 fd = open(fname,O_RDWR|O_CREAT|O_EXCL, 0644);
 141         }
 142
 143         if (fd == -1) {
 144                 fd = open(fname,O_RDWR);
 145         }
 146
 147         if (fd == -1) {
 148                 DEBUG(1,("couldn't open lock file %s\n",fname));
 149                 return(False);
 150         }
 151
 152         if (fcntl_lock(fd,F_SETLKW,0,1,F_WRLCK)==False) {
 153                 DEBUG(0,("ERROR: can't get lock on %s\n", fname));
 154                 return False;
 155         }
 156
 157         total_recs = file_size(fname) / sizeof(crec);
 158
 159         /* find a free spot */
 160         for (i=0;i<max_connections;i++) {
 161                 if (i>=total_recs ||
 162                     lseek(fd,i*sizeof(crec),SEEK_SET) != i*sizeof(crec) ||
 163                     read(fd,&crec,sizeof(crec)) != sizeof(crec)) {
 164                         if (foundi < 0) foundi = i;
 165                         break;
 166                 }
 167
 168                 if (Clear && crec.pid && !process_exists(crec.pid)) {
 169                         lseek(fd,i*sizeof(crec),SEEK_SET);
 170                         bzero((void *)&crec,sizeof(crec));
 171                         write(fd, &crec,sizeof(crec));
 172                         if (foundi < 0) foundi = i;
 173                         continue;
 174                 }
 175                 if (foundi < 0 && (!crec.pid || !process_exists(crec.pid))) {
 176                         foundi=i;
 177                         if (!Clear) break;
 178                 }
 179         }
 180
 181         if (foundi < 0) {
 182                 DEBUG(3,("no free locks in %s\n",fname));
 183                 if (fcntl_lock(fd,F_SETLKW,0,1,F_UNLCK)==False) {
 184                         DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 185                 }
 186                 close(fd);
 187                 return(False);
 188         }
 189
 190         /* fill in the crec */
 191         bzero((void *)&crec,sizeof(crec));
 192         crec.magic = 0x280267;
 193         crec.pid = getpid();
 194         crec.cnum = cnum;
 195         if (cnum != -1) {
 196                 crec.uid = Connections[cnum].uid;
 197                 crec.gid = Connections[cnum].gid;
 198                 StrnCpy(crec.name,lp_servicename(SNUM(cnum)),sizeof(crec.name)-1);
 199         }
 200         crec.start = time(NULL);
 201
 202         StrnCpy(crec.machine,remote_machine,sizeof(crec.machine)-1);
 203         StrnCpy(crec.addr,client_addr(),sizeof(crec.addr)-1);
 204
 205         /* make our mark */
 206         if (lseek(fd,foundi*sizeof(crec),SEEK_SET) != foundi*sizeof(crec) ||
 207             write(fd, &crec,sizeof(crec)) != sizeof(crec)) {
 208                 if (fcntl_lock(fd,F_SETLKW,0,1,F_UNLCK)==False) {
 209                         DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 210                 }
 211                 close(fd);
 212                 return(False);
 213         }
 214
 215         if (fcntl_lock(fd,F_SETLKW,0,1,F_UNLCK)==False) {
 216                 DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 217         }
 218
 219         close(fd);
 220         return(True);
 221 }