UUCP remote.unknown File

The other file that affects the use of communication facilities is the remote.unknown file. This file is a binary program that executes when a machine that is not found in any of the Systems files starts a conversation. This program logs the conversation attempt and drops the connection.

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Caution - If you change the permissions of the remote.unknown file so that it cannot execute, your system accepts connections from any system.

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This program executes when a machine that is not in any of the Systems starts a conversation. The program logs the conversation attempt but fails to make a connection. If you change the permissions of this file so that it cannot execute (chmod 000 remote.unknown), your system accepts any conversation requests. This is not a trivial change, and you should have good reasons for making it.

UUCP Administrative Files

The UUCP administrative files are described next. These files are created in spool directories to lock devices, hold temporary data, or keep information about remote transfers or executions.

• Temporary data files (TM) - These data files are created by UUCP processes under the spool directory /var/spool/uucp/x when a file is received from another computer. The directory x has the same name as the remote computer that is sending the file. The names of the temporary data files have the following format:

  TM.pid.ddd

  pid is a process ID and ddd is a sequential three-digit number that starts at 0.

  When the entire file is received, the TM.pid.ddd file is moved to the path name that is specified in the C.sysnxxxx file (discussed subsequently) that caused the transmission. If processing is abnormally terminated, the TM.pid.ddd file can remain in the x directory. These files should be automatically removed by uucleanup.

• Lock files (LCK) - Lock files are created in the /var/spool/locks directory for each device in use. Lock files prevent duplicate conversations and multiple attempts to use the same calling device. The following table shows the different types of UUCP lock files.

Table 40-10 UUCP Lock Files

File Name	Description
LCK..sys	sys represents the name of the computer that is using the file
LCK.dev	dev represents the name of a device that is using the file
LCK.LOG	LOG represents a locked UUCP log file

These files can remain in the spool directory if the communications link is unexpectedly dropped (usually on computer crashes). The lock file is ignored (removed) after the parent process is no longer active. The lock file contains the process ID of the process that created the lock.

• Work file (C.) - Work files are created in a spool directory when work (file transfers or remote command executions) has been queued for a remote computer. The names of work files have the following format:

  C.sysnxxxx

  sys is the name of the remote computer, n is the ASCII character that represents the grade (priority) of the work, and xxxx is the four-digit job sequence number that is assigned by UUCP. Work files contain the following information:

  • Full path name of the file to be sent or requested.

  • Full path name of the destination or user or file name.

  • User login name.

  • List of options.

  • Name of associated data files in the spool directory. If the uucp -C or uuto -p option was specified, a dummy name (D.0) is used.

  • Mode bits of the source file.

  • Remote user's login name to be notified on completion of the transfer.

• Data file(D.) - Data files are created when you specify on the command line to copy the source file to the spool directory. The names of data files have the following format:

  D.systmxxxxyyy - systm is the first five characters in the name of the remote computer, xxxx is a four-digit job sequence number assigned by uucp. The four-digit job sequence number can be followed by a subsequence number. yyy is used when several D. files are created for a work (C.) file.

• X. (execute file) - Execute files are created in the spool directory prior to remote command executions. The names of execute files have the following format:

  X.sysnxxxx

  sys is the name of the remote computer. n is the character that represents the grade (priority) of the work. xxxx is a four-digit sequence number that is assigned by UUCP. Execute files contain the following information:

  • Requester's login and computer name

  • Names of files that are required for execution

  • Input to be used as the standard input to the command string

  • Computer and file name to receive standard output from the command execution

  • Command string

  • Option lines for return status requests

UUCP Error Messages

This section lists the error messages that are associated with UUCP.

UUCP ASSERT Error Messages

The following table lists ASSERT error messages.

Table 40-11 ASSERT Error Messages

Error Message	Description or Action
CAN'T OPEN	An open() or fopen() failed.
CAN'T WRITE	A write(), fwrite(), fprint(), or similar command, failed.
CAN'T READ	A read(), fgets(), or similar command failed.
CAN'T CREATE	A creat() call failed.
CAN'T ALLOCATE	A dynamic allocation failed.
CAN'T LOCK	An attempt to make a LCK (lock) file failed. In some situations, this is a fatal error.
CAN'T STAT	A stat() call failed.
CAN'T CHMOD	A chmod() call failed.
CAN'T LINK	A link() call failed.
CAN'T CHDIR	A chdir() call failed.
CAN'T UNLINK	An unlink() call failed.
WRONG ROLE	This is an internal logic problem.
CAN'T MOVE TO CORRUPTDIR	An attempt to move some bad C. or X. files to the /var/spool/uucp/.Corrupt directory failed. The directory is probably missing or has wrong modes or owner.
CAN'T CLOSE	A close() or fclose() call failed.
FILE EXISTS	The creation of a C. or D. file is attempted, but the file exists. This error occurs when a problem arises with the sequence file access. Usually indicates a software error.
NO uucp SERVICE NUMBER	A TCP/IP call is attempted, but no entry is in /etc/services for UUCP.
BAD UID	The user ID is not in the password database. Check name service configuration.
BAD LOGIN_UID	Same as previous description.
BAD LINE	A bad line is in the Devices file. Not enough arguments on one or more lines.
SYSLST OVERFLOW	An internal table in gename.c overflowed. A single job attempted to talk to more than 30 systems.
TOO MANY SAVED C FILES	Same as previous description.
RETURN FROM fixline ioctl	An ioctl(2), which should never fail, failed. A system driver problem has occurred.
BAD SPEED	A bad line speed appears in the Devices or Systems file (Class or Speed field).
BAD OPTION	A bad line or option is in the Permissions file. It must be fixed immediately.
PKCGET READ	The remote machine probably hung up. No action need be taken.
PKXSTART	The remote machine aborted in a nonrecoverable way. This error can usually be ignored.
TOO MANY LOCKS	An internal problem has occurred. Contact your system vendor.
XMV ERROR	A problem with some file or directory has occurred. The spool directory is the probable cause, as the modes of the destinations were supposed to be checked before this process was attempted.
CAN'T FORK	An attempt to make a fork and exec failed. The current job should not be lost but will be attempted later (uuxqt). No action is needed.