ckccfg.txt

C-Kermit源码。是使用串口/Modem和网络通讯的程序

signal.h).  If this code should cause problems, you can disable it without
disabling the NAWS feature altogether, by defining NOSIGWINCH at compile time.

8.1.5. Enabling Incoming TCP/IP Connections

This feature lets you "set host * <port>" and wait for an incoming connection
on the given port.  This feature is enabled automatically at compile if
TCPSOCKET is defined and SELECT is also defined.  But watch out, simply
defining SELECT on the cc command line does not guarantee successful
compilation or linking (see section 11).

If you want to disable incoming TCP/IP connections, then build C-Kermit
with:

  -DNOLISTEN

8.1.6. Disabling "SET TCP" Options.

The main reason for this is because of header file / prototype conflicts at
compile time regardting get/setsockopt().  If you can't fix them (without
breaking other builds), just include the following in CFLAGS:

  -DNOTCPOPTS


8.2. X.25

X.25 support requires (a) a SUN, (b) the SunLink product (libraries and header
files), and (c) an X.25 connection into your SUN, or else Stratus VOS and the
appropriate X.25 development tools.  Support for IBM AIXlink X.25 was added
in C-Kermit 6.1.

In UNIX, special makefile entries sunos4x25 and sunos41x25 (for SUNOS 4.0 and
4.1, respectively), or aix41x25, are provided to build in this feature, but
they only work if conditions (a)-(c) are met.  To request this feature,
include -DSUNX25 (or -DIBMX25) in CFLAGS.

SUNX25 (or -DIBMX25) and TCPSOCKET can be freely mixed and matched.

8.3. Other Networks

Support for other networking methods -- NETBIOS, LAT, Named Pipes, etc --
is included in CK*NET.H and CK*NET.C for implementations (such as OS/2) where
these methods are supported.

Provision is made in the organization of the modules, header files, commands,
etc, for addition of new network types such as DECnet, X.25 for other systems
(HP-UX, VMS, etc), and so on.  Send email to [e-mail] if you are
interested in working on such a project.

9. EXCEPTION HANDLING

The setjmp/longjmp mechanism is used for handling exceptions.  The jump
buffer is of type jmp_buf, which almost everywhere is typedef'd as an array,
in which case you should have no trouble compiling the exception-handling
code.  However, if you are building C-Kermit in/for an environment where
jmp_buf is something other than an array (e.g. a struct), then you'll have
to define the following symbol:

  JBNOTARRAY

10. SECURITY FEATURES

Compiling with the NOPUSH symbol defined removes all the "shell escape"
features from the program, including the PUSH, RUN, and SPAWN commands, the
"!"  and "@" command prefixes, OPEN !READ, OPEN !WRITE, job control (including
the SUSPEND command), the REDIRECT command, shell/DCL escape from CONNECT
mode, as well as the server's execution of REMOTE HOST commands (and, of
course, the ENABLE HOST command).  Add NODISPO to also prevent acceptance of
incoming MAIL or REMOTE PRINT files.  For UNIX, also be sure to read
CKUINS.TXT about set[ug]id installation.  Additional restrictions can be
enforced when in server mode; read about the DISABLE command.

Compiling with NOCCTRAP prevents the trapping of SIGINT by Kermit.  Thus
if the user generates a SIGINT signal (e.g. by typing the system's interrupt
character), Kermit will exit immediately, rather than returning to its
prompt.

NOPUSH and NOCCTRAP together allow Kermit to be run from restricted shells,
preventing access to system functions.

11. ENABLING SELECT()

Kermit works best if it can do nonblocking reads, nondestructive input buffer
checking, and millisecond sleeps.  All of these functions can be accomplished
by the select() function, which, unfortunately, is not universally available.
Furthermore, select() is required if incoming TCP/IP connections are to be
supported.

select() was introduced with Berkeley UNIX, rejected by AT&T for System V,
but is gradually creeping in to all UNIX versions (and other operating systems
too) by virtue of its presence in the sockets library, which is needed for
TCP/IP.  AT&T SVID for System V R4 includes select(), but that does not mean
that all SVR4 implementations have it.

Furthermore, even when select() is available, it might work only on socket
file descriptors, but not on others like serial ports, pipes, etc.  For
example, in AOS/VS and BeOS (DR8 and earlier), it works only with file
descriptors that were created by socket() and opened by connect() or accept().

Other alternatives include poll() and rdchk().  Only one of these three
functions should be included.  The following symbols govern this:

  SELECT  Use select() (BSD, or systems with sockets libraries)
  CK_POLL Use poll()   (System V)
  RDCHK   Use rdchk()  (SCO)

If your system supports the select() function, but your version of C-Kermit
does not, try adding:

  -DSELECT

to the CFLAGS, and removing -DRDCHK or -DCK_POLL if it is there.  If you get
compilation errors, some adjustments to ck*tio.c and/or ck*net.c might be
needed; search for SELECT (uppercase) in these files (note that there are
several variations on the calling conventions for select()).

Various macros and data types need to be defined in order to use select().
Usually these are picked up from <types.h> or <sys/types.h>.  But on some
systems, they are in <sys/select.h>.  In that case, add the following:

  -DSELECT_H

to the CFLAGS to tell C-Kermit to #include <sys/select.h>.  A good indication
that you need to do this would be if you get compile-time complaints about
"fd_set" or "FD_SET" not being declared or defined.

In UNIX, the use of select() vs fork() in the CONNECT command is independent
of the above considerations, and is governed by choosing a particular makefile
target.

As of C-Kermit 6.1, select() is also the preferred control mechanism for
the CONNECT command.  Unfortunately, the structures used by the original
UNIX CONNECT command, based on fork(), and those used by select(), are so
different, it was not practical to implement them both in one module.  So the
select()-based CONNECT command module for UNIX is ckucns.c, and the fork-based
one remains ckucon.c.  To choose the fork-based one, which is more portable
(but slower and more fragile), use "wermit" as the make target.  To choose the
select-based one, use "xermit" (as is done, for example, in the SunOS 4.1
make target).  Only do this if you can verify that the CONNECT command works
on serial connections and PIPE connections as well as TCP connections.

  The select() version of ckucon.c MUST be used if encryption is to be
  done, since the fork() version loses its ability to share vital state
  information between the two forks.  Also note that the select() version
  is superior in many other ways too.  For example, it recovers better from
  exterior killing, forced disconnections, etc.

SHOW VERSIONS tells whether the CONNECT module uses fork() or select().


12. I/O REDIRECTION

The REDIRECT command allows a local program to be run with its i/o redirected
over the communications connection.  Your version of C-Kermit has a REDIRECT
command if it was built with the following CFLAG:

  -DCK_REDIR

This, in turn, is possible only if the underlying API is there.  In the case
of UNIX this is just the wait() system call, so all UNIX versions get this
feature as of 6.0.192 (earlier versions needed a <sys/wait.h> header file
defining the symbols WIFEXITED and WEXITSTATUS).

As of version 6.1, file transfer can be done using pipes and filters.  To
enable this feature, #define PIPESEND (and fill in the code).  To disable on
systems where it is normally enabled, define NOPIPESEND.  This feature is, of
course, also disabled by building with NOPUSH (or giving the "nopush" command
at runtime).

Version 6.1 also adds the PIPE and SET HOST /COMMAND commands, which provide
another form of redirection.  This feature is selected with -DNETCMD.  CK_RDIR
must also be defined, since the same mechanisms are used internally.


13. FLOATING-POINT TIMERS

C-Kermit 6.1 can be configured to use high-precision file-transfer timers
for more accurate statistics.  This feature is enabled with:

  -DGFTIMER

and disabled with:

  -DNOGFTIMER

If you try to build with -DGFTIMER but you get compilation errors, either
fix them (and send email to [e-mail] telling what you did), or
else give up and use -DNOGFTIMER instead.  Hint: depending on your machine
architecture, you might have better luck using double than float as the data
type for floating-point numbers, or vice versa.  Look in ckcdeb.h for the
section that handles this (search for "float").

If it builds successfully, test the result carefully -- watch the time-related
fields in the fullscreen file-transfer display and the numbers reported by the
STATISTICS command.  If the results are nonsense, then try switching from
float to double or vice versa as noted in the previous paragraph.  If that
doesn't help, use -DNOFGTIMER.


14. SPECIAL CONFIGURATIONS

As of C-Kermit 7.0, if you build C-Kermit normally, but with -DNOICP (No
Interactive Command Parser), you get a program capable of making serial
connections (but not dialing) and network connections (if TCPSOCKET or
other network option included), and can also transfer files using Kermit
protocol, but only via autodownload/upload.  Furthermore, if you call
the executable "telnet", it will act like Telnet -- using the command-line
options.  However, in this case there is nothing to escape back to, so if
you type Ctrl-\c, it just prints a message to this effect.

You can also build C-Kermit with -DNOXFER, meaning omit all the file-transfer
features.  This leaves you with a scriptable communications program that is
considerably smaller than the full C-Kermit.


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APPENDIX I: SUMMARY OF COMPILE-TIME OPTIONS

These are the symbols that can be specified on the cc command line, listed
alphabetically.  Others are used internally, including those taken from header
files, those defined by the compiler itself, and those inferred from the ones
given below.  Kermit's SHOW VERSIONS command attempts to display most of
these.  See ckcdeb.h and ckcnet.h for inference rules.  For example SVR3
implies ATTSV, MULTINET implies TCPSOCKET, and so on.

The following options are not included in all makefile entries, but they are
beneficial if they work.  It is recommended that you add them to your makefile
entry if they are lacking and test the result.  If it's OK, let me know and
I'll add them to the official makefile:

DYNAMIC        Dynamic packet buffer allocation, bigger packets allowed, etc.
NOSETBUF       Don't do unbuffered single-character writes to the console.
               This tends to speed up CONNECT mode.

Here is the complete list of the Kermit-specific compile-time switches:

ACUCNTRL       Select BSD 4.3-style acucntrl() bidirectional tty control.
aegis          Build for Apollo Aegis (predefined on Apollo systems).
AIX370         Build for IBM AIX/370 for IBM mainframes.
AIXESA         Build for IBM AIX/ESA for IBM mainframes.
AIXPS2         Build for IBM AIX 3.0 for PS/2 series (never formally released).
AIXRS          Build for IBM AIX 3.x on RS/6000.
AIX41          Build for IBM AIX 4.x on RS/6000.
AMIGA          Build for Commodore Amiga with Intuition OS.
ATT6300        Build for AT&T 6300 PLUS.
ATT7300        Build for AT&T 7300 UNIX PC (3B1).
ATTSV          Build for AT&T System III or V UNIX.
AUX            Build for Apple A/UX for the Macintosh.
BIGBUFOK       OK to use big buffers - "memory is not a problem"
BPS_xxxx       Enable SET SPEED xxxx
BSD29          Build for BSD 2.9 or 2.10.
BSD4           Build for BSD 4.2.
BSD41          Build for BSD 4.1.
BSD43          Build for BSD 4.3.
BSD44          Build for BSD 4.4.
C70            Build for BBN C/70.
CIE            Build for CIE Systems 680/20.
CKCONINTB4CB   Work around prompt-disappears after escape back from CONNECT.
CKLOGDIAL      Enable connection log.
CKMAXPATH      Maximum length for a fully qualified filename.
CKREGEX        Include [...] or {xxx,xxx,xxx} matching in ckmatch().
CKSYSLOG       Enable syslogging.
CK_ANSIC       Enable ANSI C constructs - prototypes, etc.