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 fstring remote_machine;
  26
  27 extern int DEBUGLEVEL;
  28
  29 /****************************************************************************
  30 simple routines to do connection counting
  31 ****************************************************************************/
  32 BOOL yield_connection(connection_struct *conn,char *name,int max_connections)
  33 {
  34         struct connect_record crec;
  35         pstring fname;
  36         int fd;
  37         int mypid = getpid();
  38         int i;
  39
  40         DEBUG(3,("Yielding connection to %s\n",name));
  41
  42         if (max_connections <= 0)
  43                 return(True);
  44
  45         bzero(&crec,sizeof(crec));
  46
  47         pstrcpy(fname,lp_lockdir());
  48         trim_string(fname,"","/");
  49
  50         pstrcat(fname,"/");
  51         pstrcat(fname,name);
  52         pstrcat(fname,".LCK");
  53
  54         fd = sys_open(fname,O_RDWR,0);
  55         if (fd == -1) {
  56                 DEBUG(2,("Couldn't open lock file %s (%s)\n",fname,strerror(errno)));
  57                 return(False);
  58         }
  59
  60         if (fcntl_lock(fd,SMB_F_SETLKW,0,1,F_WRLCK)==False) {
  61                 DEBUG(0,("ERROR: can't get lock on %s\n", fname));
  62                 return False;
  63         }
  64
  65         /* find the right spot */
  66         for (i=0;i<max_connections;i++) {
  67                 if (read(fd, &crec,sizeof(crec)) != sizeof(crec)) {
  68                         DEBUG(2,("Entry not found in lock file %s\n",fname));
  69                         if (fcntl_lock(fd,SMB_F_SETLKW,0,1,F_UNLCK)==False) {
  70                                 DEBUG(0,("ERROR: can't release lock on %s\n", fname));
  71                         }
  72                         close(fd);
  73                         return(False);
  74                 }
  75                 if (crec.pid == mypid && crec.cnum == conn->cnum)
  76                         break;
  77         }
  78
  79         if (crec.pid != mypid || crec.cnum != conn->cnum) {
  80                 if (fcntl_lock(fd,SMB_F_SETLKW,0,1,F_UNLCK)==False) {
  81                         DEBUG(0,("ERROR: can't release lock on %s\n", fname));
  82                 }
  83                 close(fd);
  84                 DEBUG(2,("Entry not found in lock file %s\n",fname));
  85                 return(False);
  86         }
  87
  88         bzero((void *)&crec,sizeof(crec));
  89
  90         /* remove our mark */
  91         if (sys_lseek(fd,i*sizeof(crec),SEEK_SET) != i*sizeof(crec) ||
  92             write(fd, &crec,sizeof(crec)) != sizeof(crec)) {
  93                 DEBUG(2,("Couldn't update lock file %s (%s)\n",fname,strerror(errno)));
  94                 if (fcntl_lock(fd,SMB_F_SETLKW,0,1,F_UNLCK)==False) {
  95                         DEBUG(0,("ERROR: can't release lock on %s\n", fname));
  96                 }
  97                 close(fd);
  98                 return(False);
  99         }
 100
 101         if (fcntl_lock(fd,SMB_F_SETLKW,0,1,F_UNLCK)==False) {
 102                 DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 103         }
 104
 105         DEBUG(3,("Yield successful\n"));
 106
 107         close(fd);
 108         return(True);
 109 }
 110
 111
 112 /****************************************************************************
 113 simple routines to do connection counting
 114 ****************************************************************************/
 115 BOOL claim_connection(connection_struct *conn,char *name,int max_connections,BOOL Clear)
 116 {
 117         extern int Client;
 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         pstrcat(fname,"/");
 136         pstrcat(fname,name);
 137         pstrcat(fname,".LCK");
 138
 139         if (!file_exist(fname,NULL)) {
 140                 fd = sys_open(fname,O_RDWR|O_CREAT|O_EXCL, 0644);
 141         }
 142
 143         if (fd == -1) {
 144                 fd = sys_open(fname,O_RDWR,0);
 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,SMB_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                     sys_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                         if(sys_lseek(fd,i*sizeof(crec),SEEK_SET) != i*sizeof(crec)) {
 170               DEBUG(0,("claim_connection: ERROR: sys_lseek failed to seek \
 171 to %d\n", i*sizeof(crec) ));
 172               continue;
 173             }
 174                         bzero((void *)&crec,sizeof(crec));
 175                         write(fd, &crec,sizeof(crec));
 176                         if (foundi < 0) foundi = i;
 177                         continue;
 178                 }
 179                 if (foundi < 0 && (!crec.pid || !process_exists(crec.pid))) {
 180                         foundi=i;
 181                         if (!Clear) break;
 182                 }
 183         }
 184
 185         if (foundi < 0) {
 186                 DEBUG(3,("no free locks in %s\n",fname));
 187                 if (fcntl_lock(fd,SMB_F_SETLKW,0,1,F_UNLCK)==False) {
 188                         DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 189                 }
 190                 close(fd);
 191                 return(False);
 192         }
 193
 194         /* fill in the crec */
 195         bzero((void *)&crec,sizeof(crec));
 196         crec.magic = 0x280267;
 197         crec.pid = getpid();
 198         if (conn) {
 199                 crec.cnum = conn->cnum;
 200                 crec.uid = conn->uid;
 201                 crec.gid = conn->gid;
 202                 StrnCpy(crec.name,
 203                         lp_servicename(SNUM(conn)),sizeof(crec.name)-1);
 204         } else {
 205                 crec.cnum = -1;
 206         }
 207         crec.start = time(NULL);
 208
 209         StrnCpy(crec.machine,remote_machine,sizeof(crec.machine)-1);
 210         StrnCpy(crec.addr,client_addr(Client),sizeof(crec.addr)-1);
 211
 212         /* make our mark */
 213         if (sys_lseek(fd,foundi*sizeof(crec),SEEK_SET) != foundi*sizeof(crec) ||
 214             write(fd, &crec,sizeof(crec)) != sizeof(crec)) {
 215                 if (fcntl_lock(fd,SMB_F_SETLKW,0,1,F_UNLCK)==False) {
 216                         DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 217                 }
 218                 close(fd);
 219                 return(False);
 220         }
 221
 222         if (fcntl_lock(fd,SMB_F_SETLKW,0,1,F_UNLCK)==False) {
 223                 DEBUG(0,("ERROR: can't release lock on %s\n", fname));
 224         }
 225
 226         close(fd);
 227         return(True);
 228 }