/*------------------------------------------------------------------------- | lfd is a lock file server. | Copyright 2002-2004 by Trent Jarvi trentjarvi@yahoo.com | | This software is free software; you can redistribute it and/or | modify it under the terms of the GNU General Public | License as published by the Free Software Foundation; either | version 2 of the License, or (at your option) any later version. | | This library is distributed in the hope that it will be useful, | but WITHOUT ANY WARRANTY; without even the implied warranty of | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | Library General Public License for more details. | | You should have received a copy of the GNU General Public | License along with this software; if not, write to the Free | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA --------------------------------------------------------------------------*/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define FHS #define LOCKFILEPREFIX "LCK.." #define LOCK fhs_lock #define UNLOCK fhs_unlock #define LOCKDIR "/var/lock" char hostname[256]; #define M200 "200 Command okay.\n" #define M202 "202 Command not implemented\n" #define M220 "220 %s Lock File Server (Version rxtx-1.5-9) ready\n", hostname #define M221 "221 Thank you for using the Lock File service on %s\n", hostname #define M450 "450 : File busy.\n" #define M500 "500 '%s': command not understood\n", str #define M550 "550 : Permission denied.\n" int is_device_locked( const char * ); int check_group_uucp(); int check_lock_status( const char * ); int check_lock_pid( const char *, int ); #define UNEXPECTED_LOCK_FILE "RXTX Error: Unexpected lock file: %s\n Please report to the RXTX developers\n" #define UUCP_ERROR "\n\n\nRXTX WARNING: This library requires the user running applications to be in\ngroup uucp. Please consult the INSTALL documentation. More information is\navaiable under the topic 'How can I use Lock Files with rxtx?'\n" extern int errno; /*---------------------------------------------------------- fhs_lock accept: The name of the device to try to lock termios struct perform: Create a lock file if there is not one already. return: 1 on failure 0 on success exceptions: none comments: This is for linux and freebsd only currently. I see SVR4 does this differently and there are other proposed changes to the Filesystem Hierachy Standard more reading: ----------------------------------------------------------*/ int fhs_lock( const char *filename, int pid ) { /* * There is a zoo of lockdir possibilities * Its possible to check for stale processes with most of them. * for now we will just check for the lockfile on most * Problem lockfiles will be dealt with. Some may not even be in use. * */ int fd,j; char lockinfo[12], message[80]; char file[80], *p; j = strlen( filename ); p = ( char * ) filename + j; /* FIXME need to handle subdirectories /dev/cua/... SCO Unix use lowercase all the time taj */ while( *( p - 1 ) != '/' && j-- != 1 ) { #if defined ( __unixware__ ) *p = tolower( *p ); #endif /* __unixware__ */ p--; } sprintf( file, "%s/LCK..%s", LOCKDIR, p ); if ( check_lock_status( filename ) ) { /* syslog( LOG_INFO, "fhs_lock() lockstatus fail\n" ); */ return 1; } fd = open( file, O_CREAT | O_WRONLY | O_EXCL, 0444 ); if( fd < 0 ) { sprintf( message, "RXTX fhs_lock() Error: creating lock file: %s: %s\n", file, strerror(errno) ); syslog( LOG_INFO, message ); return 1; } sprintf( lockinfo, "%10d\n", pid ); sprintf( message, "fhs_lock: creating lockfile: %s\n", lockinfo ); //syslog( LOG_INFO, message ); write( fd, lockinfo, 11 ); close( fd ); return 0; } /*---------------------------------------------------------- uucp_lock accept: char * filename. Device to be locked perform: Try to get a uucp_lock return: int 0 on success exceptions: none comments: The File System Hierarchy Standard http://www.pathname.com/fhs/ UUCP Lock Files http://docs.freebsd.org/info/uucp/uucp.info.UUCP_Lock_Files.html FSSTND ftp://tsx-11.mit.edu/pub/linux/docs/linux-standards/fsstnd/ Proposed Changes to the File System Hierarchy Standard ftp://scicom.alphacdc.com/pub/linux/devlock-0.X.tgz "UNIX Network Programming", W. Richard Stevens, Prentice-Hall, 1990, pages 96-101. There is much to do here. 1) UUCP style locks (done) /var/spool/uucp 2) SVR4 locks /var/spool/locks 3) FSSTND locks (done) /var/lock 4) handle stale locks (done except kermit locks) 5) handle minicom lockfile contents (FSSTND?) " 16929 minicom root\n" (done) 6) there are other Lock conventions that use Major and Minor numbers... 7) Stevens recommends LCK.. most are caught above. If they turn out to be problematic rather than an exercise, we will handle them. ----------------------------------------------------------*/ int uucp_lock( const char *filename, int pid ) { char lockfilename[80], lockinfo[12], message[80]; char name[80]; int fd; struct stat buf; sprintf( message, "uucp_lock( %s );\n", filename ); syslog( LOG_INFO, message ); if ( check_lock_status( filename ) ) { syslog( LOG_INFO, "RXTX uucp check_lock_status true\n" ); return 1; } if ( stat( LOCKDIR, &buf ) != 0 ) { syslog( LOG_INFO, "RXTX uucp_lock() could not find lock directory.\n" ); return 1; } if ( stat( filename, &buf ) != 0 ) { syslog( LOG_INFO, "RXTX uucp_lock() could not find device.\n" ); sprintf( message, "uucp_lock: device was %s\n", name ); syslog( LOG_INFO, message ); sprintf( message, "Filename is : %s \n", filename ); syslog( LOG_INFO, message ); return 1; } sprintf( lockfilename, "%s/LK.%03d.%03d.%03d", LOCKDIR, (int) major( buf.st_dev ), (int) major( buf.st_rdev ), (int) minor( buf.st_rdev ) ); sprintf( lockinfo, "%10d\n", pid ); if ( stat( lockfilename, &buf ) == 0 ) { sprintf( message, "RXTX uucp_lock() %s is there\n", lockfilename ); syslog( LOG_INFO, message ); syslog( LOG_INFO, message ); return 1; } fd = open( lockfilename, O_CREAT | O_WRONLY | O_EXCL, 0444 ); if( fd < 0 ) { sprintf( message, "RXTX uucp_lock() Error: creating lock file: %s\n", lockfilename ); syslog( LOG_INFO, message ); return 1; } write( fd, lockinfo,11 ); close( fd ); /* setgid( nobody ); setuid( nobody ); */ return 0; } /*---------------------------------------------------------- check_lock_status accept: the lock name in question perform: Make sure everything is sane return: 0 on success exceptions: none comments: ----------------------------------------------------------*/ int check_lock_status( const char *filename ) { struct stat buf; /* First, can we find the directory? */ if ( stat( LOCKDIR, &buf ) != 0 ) { syslog( LOG_INFO, "check_lock_status: could not find lock directory.\n" ); return 1; } /* OK. Are we able to write to it? If not lets bail */ if ( check_group_uucp() ) { syslog( LOG_INFO, "check_lock_status: No permission to create lock file. please see: How can I use Lock Files with rxtx? in INSTALL\n" ); return 1; } /* is the device alread locked */ if ( is_device_locked( filename ) ) { /* syslog( LOG_INFO, "check_lock_status: device is locked by another application\n" ); */ return 1; } return 0; } /*---------------------------------------------------------- fhs_unlock accept: The name of the device to unlock perform: delete the lock file return: none exceptions: none comments: This is for linux only currently. I see SVR4 does this differently and there are other proposed changes to the Filesystem Hierachy Standard ----------------------------------------------------------*/ int fhs_unlock( const char *filename, int openpid ) { char file[80],*p, msg[80]; struct stat buf; int i; i = strlen( filename ); p = ( char * ) filename + i; sprintf( msg, "fhs_unlock %s\n", filename ); /* syslog( LOG_INFO, msg ); */ /* FIXME need to handle subdirectories /dev/cua/... */ while( *( p - 1 ) != '/' && i-- != 1 ) p--; sprintf( file, "%s/LCK..%s", LOCKDIR, p ); #ifdef asdf if ( ! check_lock_status( p ) ) { sprintf( msg, "fhs_unlock %s check_lock_status\n", filename ); syslog( LOG_INFO, msg ); return 0; } #endif if ( stat( filename, &buf ) != 0 ) { /* hmm the file is not there? */ syslog( LOG_INFO, "uucp_unlock() no such device\n" ); return(0); } if( !check_lock_pid( file, openpid ) ) { unlink(file); //syslog( LOG_INFO,"fhs_unlock: Removing LockFile\n"); return( 0 ); } else { syslog( LOG_INFO,"fhs_unlock: Unable to remove LockFile\n"); return( 1 ); } } /*---------------------------------------------------------- uucp_unlock accept: char *filename the device that is locked perform: remove the uucp lockfile if it exists return: none exceptions: none comments: http://docs.freebsd.org/info/uucp/uucp.info.UUCP_Lock_Files.html ----------------------------------------------------------*/ void uucp_unlock( const char *filename, int openpid ) { struct stat buf; char file[80], message[80]; /* FIXME */ sprintf( message, "uucp_unlock( %s );\n", filename ); syslog( LOG_INFO, message ); if ( stat( filename, &buf ) != 0 ) { /* hmm the file is not there? */ syslog( LOG_INFO, "uucp_unlock() no such device\n" ); return; } sprintf( file, LOCKDIR"/LK.%03d.%03d.%03d", (int) major( buf.st_dev ), (int) major( buf.st_rdev ), (int) minor( buf.st_rdev ) ); if ( stat( file, &buf ) != 0 ) { /* hmm the file is not there? */ syslog( LOG_INFO, "uucp_unlock no such lockfile\n" ); return; } if( !check_lock_pid( file, openpid ) ) { sprintf( message, "uucp_unlock: unlinking %s\n", file ); syslog( LOG_INFO, message ); unlink(file); } else { sprintf( message, "uucp_unlock: unlinking failed %s\n", file ); syslog( LOG_INFO, message ); } } /*---------------------------------------------------------- check_lock_pid accept: the name of the lockfile perform: make sure the lock file is ours. return: 0 on success exceptions: none comments: ----------------------------------------------------------*/ int check_lock_pid( const char *file, int openpid ) { int fd, lockpid; char pid_buffer[12]; char message[80]; fd=open( file, O_RDONLY ); if ( fd < 0 ) { return( 1 ); } if ( read( fd, pid_buffer, 11 ) < 0 ) { close( fd ); return( 1 ); } close( fd ); pid_buffer[11] = '\0'; lockpid = atol( pid_buffer ); if ( lockpid != openpid ) { if( kill( (pid_t) lockpid, 0 ) && errno==ESRCH ) { return( 0 ); } sprintf(message, "check_lock_pid: lock = %s pid = %i gpid=%i openpid=%i\n", pid_buffer, (int) getpid(), (int) getppid(), openpid ); syslog( LOG_INFO, message ); return( 1 ); } return( 0 ); } /*---------------------------------------------------------- check_group_uucp accept: none perform: check if the user is root or in group uucp return: 0 on success exceptions: none comments: This checks if the effective user is in group uucp so we can create lock files. If not we give them a warning and bail. If its root we just skip the test. if someone really wants to override this they can use the USER_LOCK_DIRECTORY --not recommended. In a recent change RedHat 7.2 decided to use group lock. In order to get around this we just check the group id of the lock directory. ----------------------------------------------------------*/ int check_group_uucp() { #ifndef USER_LOCK_DIRECTORY int group_count; struct passwd *user = getpwuid( geteuid() ); struct stat buf; char msg[80]; gid_t list[ NGROUPS_MAX ]; if( stat( LOCKDIR, &buf) ) { sprintf( msg, "check_group_uucp: Can not find Lock Directory: %s\n", LOCKDIR ); syslog( LOG_INFO, msg ); return( 1 ); } group_count = getgroups( NGROUPS_MAX, list ); list[ group_count ] = geteuid(); if( user->pw_gid ) { while( group_count >= 0 && buf.st_gid != list[ group_count ] ) { group_count--; } if( buf.st_gid == list[ group_count ] ) return 0; sprintf( msg, "%i %i\n", buf.st_gid, list[ group_count ] ); syslog( LOG_INFO, msg ); syslog( LOG_INFO, UUCP_ERROR ); return 1; } return 0; /* if( strcmp( user->pw_name, "root" ) ) { while( *g->gr_mem ) { if( !strcmp( *g->gr_mem, user->pw_name ) ) { break; } (void) *g->gr_mem++; } if( !*g->gr_mem ) { syslog( LOG_INFO, UUCP_ERROR ); return 1; } } */ #endif /* USER_LOCK_DIRECTORY */ return 0; } /*---------------------------------------------------------- The following should be able to follow symbolic links. I think the stat method used below will work on more systems. This was found while looking for information. * realpath() doesn't exist on all of the systems my code has to run on (HP-UX 9.x, specifically) ---------------------------------------------------------- int different_from_LOCKDIR(const char* ld) { char real_ld[MAXPATHLEN]; char real_LOCKDIR[MAXPATHLEN]; if (strncmp(ld, LOCKDIR, strlen(ld)) == 0) return 0; if (realpath(ld, real_ld) == NULL) return 1; if (realpath(LOCKDIR, real_LOCKDIR) == NULL) return 1; if (strncmp(real_ld, real_LOCKDIR, strlen(real_ld)) == 0) return 0; else return 1; } */ /*---------------------------------------------------------- is_device_locked accept: char * filename. The device in question including the path. perform: see if one of the many possible lock files is aready there if there is a stale lock, remove it. return: 1 if the device is locked or somethings wrong. 0 if its possible to create our own lock file. exceptions: none comments: check if the device is already locked ----------------------------------------------------------*/ int is_device_locked( const char *port_filename ) { const char *lockdirs[] = { "/etc/locks", "/usr/spool/kermit", "/usr/spool/locks", "/usr/spool/uucp", "/usr/spool/uucp/", "/usr/spool/uucp/LCK", "/var/lock", "/var/lock/modem", "/var/spool/lock", "/var/spool/locks", "/var/spool/uucp", LOCKDIR, NULL }; const char *lockprefixes[] = { "LCK..", "lk..", "LK.", NULL }; char *p, file[80], pid_buffer[20], message[80]; int i = 0, j, k, fd , pid; struct stat buf; struct stat buf2; j = strlen( port_filename ); p = ( char * ) port_filename+j; while( *( p-1 ) != '/' && j-- !=1 ) p--; while( lockdirs[i] ) { /* Look for lockfiles in all known places other than the defined lock directory for this system report any unexpected lockfiles. Is the suspect lockdir there? if it is there is it not the expected lock dir? */ if( !stat( lockdirs[i], &buf2 ) && strncmp( lockdirs[i], LOCKDIR, strlen( lockdirs[i] ) ) ) { j = strlen( port_filename ); p = ( char * ) port_filename + j; /* SCO Unix use lowercase all the time taj */ while( *( p - 1 ) != '/' && j-- != 1 ) { #if defined ( __unixware__ ) *p = tolower( *p ); #endif /* __unixware__ */ p--; } k=0; while ( lockprefixes[k] ) { /* FHS style */ sprintf( file, "%s/%s%s", lockdirs[i], lockprefixes[k], p ); if( stat( file, &buf ) == 0 ) { sprintf( message, UNEXPECTED_LOCK_FILE, file ); syslog( LOG_INFO, message ); return 1; } /* UUCP style */ stat(port_filename , &buf ); sprintf( file, "%s/%s%03d.%03d.%03d", lockdirs[i], lockprefixes[k], (int) major( buf.st_dev ), (int) major( buf.st_rdev ), (int) minor( buf.st_rdev ) ); if( stat( file, &buf ) == 0 ) { sprintf( message, UNEXPECTED_LOCK_FILE, file ); syslog( LOG_INFO, message ); return 1; } k++; } } i++; } /* OK. We think there are no unexpect lock files for this device Lets see if there any stale lock files that need to be removed. */ #ifdef FHS /* FHS standard locks */ i = strlen( port_filename ); p = ( char * ) port_filename + i; while( *(p-1) != '/' && i-- != 1) { #if defined ( __unixware__ ) *p = tolower( *p ); #endif /* __unixware__ */ p--; } sprintf( file, "%s/%s%s", LOCKDIR, LOCKFILEPREFIX, p ); #else /* UUCP standard locks */ sprintf( file, "%s/LK.%03d.%03d.%03d", LOCKDIR, (int) major( buf.st_dev ), (int) major( buf.st_rdev ), (int) minor( buf.st_rdev ) ); #endif /* FHS */ if( stat( file, &buf ) == 0 ) { /* check if its a stale lock */ fd=open( file, O_RDONLY ); read( fd, pid_buffer, 11 ); /* FIXME null terminiate pid_buffer? need to check in Solaris */ close( fd ); sscanf( pid_buffer, "%d", &pid ); sprintf( message, "found lock for %s with pid %i\n", file, pid ); /* syslog( LOG_INFO, message ); */ if( kill( (pid_t) pid, 0 ) && errno==ESRCH ) { sprintf( message, "RXTX Warning: Removing stale lock file. %s\n", file ); syslog( LOG_INFO, message ); if( unlink( file ) != 0 ) { snprintf( message, 80, "RXTX Error: Unable to \ remove stale lock file: %s\n", file ); syslog( LOG_INFO, message ); return 0; } } else { sprintf( message, "could not kill %i\n", pid ); /* syslog( LOG_INFO, message ); */ return 1; } } return 0; } int init( void ) { pid_t pid; if( ( pid = fork() ) < 0 ) { return(-1); } else if ( pid != 0 ) { exit( 0 ); } setsid(); chdir("/"); umask( 0 ); return( 0 ); } int process_requests( ) { for(;;) { char str[80]; char str2[80]; char *p; int ret; ret = read( 1, str, 80 ); if( ret < 80 && ret > 1 ) str[ret] = '\0'; else str[79] = '\0'; if ( !strncasecmp( str, "quit", 4 ) ) { sprintf( str, M221 ); write( 0, str, strlen( str ) ); return( 1 ); } else if( !strncasecmp( str, "lock ", 4 ) ) { char *q,*r; p = str + 5; q=p; while( *q != ' ' && *q != '\0' ) q++; if ( *q == '\0' ) { write( 0, M450, strlen( M450 ) ); return(0); } *q = '\0'; q++; r=q; while( *r != '\n' && *r != '\0' ) r++; if( *r == '\n' ) *r = '\0'; if ( LOCK( p, atoi( q ) ) ) { write( 0, M450, strlen( M450 ) ); } else { write( 0, M200, strlen( M200 ) ); } } else if( !strncasecmp( str, "unlock ", 6 ) ) { char *q,*r; p = str + 7; q=p; while( *q != ' ' && *q != '\0' ) q++; if ( *q == '\0' ) { write( 0, "q=0\n", strlen( "q=0\n" ) ); write( 0, M450, strlen( M450 ) ); return(0); } *q = '\0'; q++; r=q; while( *r != '\n' && *r != '\0' ) r++; if( *r == '\n' ) *r = '\0'; if ( UNLOCK( (const char *) p, atoi( q ) ) ) { write( 0, M450, strlen( M450 ) ); } else { write( 0, M200, strlen( M200 ) ); } } else { str[ret-2]='\0'; sprintf( str2, M500 ); write( 0, str2, strlen(str2)); } return( 0 ); } } int main( int argc, char **argv ) { char str[128]; char portstr[7]; struct sockaddr *cliaddr; struct sockaddr_in *sin; socklen_t len; openlog( argv[0], LOG_PID, 0 ); cliaddr= malloc( 128 ); len = 128; sin = ( struct sockaddr_in * ) cliaddr; cliaddr= malloc( 128 ); gethostname( hostname, 255 ); if ( !inet_ntop( AF_INET, &(sin->sin_addr), str, sizeof(str) ) ) str[0] = '\0'; if ( !ntohs( sin->sin_port ) ) { snprintf( portstr, sizeof( portstr ), ".%d", ntohs( sin->sin_port) ); strcat( str, portstr); } sprintf( str, M220 ); //syslog( LOG_INFO, str ); write( 0, str, strlen(str) ); for(;;) { if (process_requests( )) { goto exit; } } syslog( LOG_INFO, "Lock Daemon Shutting down" ); exit: closelog(); exit(0); }