ckcplm.txt

C-Kermit源码。是使用串口/Modem和网络通讯的程序

  f  = pointer to name of existing file.
  yy = pointer to a Kermit file attribute structure in which yy->date.val
       is a date of the form yyyymmdd hh:mm:ss, e.g. 19900208 13:00:00, which
       is to be used for setting or comparing the date.  Other attributes
       in the struct can also be set, such as the protection/permission
       (See Appendix I), when it makes sense (e.g. "yy->lprotect.val" can be
       set if the remote system ID matches the local one).
  x  = is a function code: 0 means to set the file's creation date as given.
       1 means compare the date from the yy struct with the file's date.
  Returns:
  -1 on any kind of error.
   0 if x is 0 and the file date was set successfully.
   0 if x is 1 and date from attribute structure > file creation date.
   1 if x is 1 and date from attribute structure <= file creation date.

VOID
zstrip(name,name2) char *name, **name2;
  Strips pathname from filename "name".  Constructs the resulting string
  in a static buffer in its own space and returns a pointer to it in name2.
  Also strips device name, file version numbers, and other "non-name" material.

(zxcmd - arguments are new, writing to a command is new)

int
zxcmd(n,s) char *s;
  Runs a system command so its output can be accessed as if it were file n.
  The command is run in ordinary, unprivileged user mode.
  If n is ZSTDIO or ZCTERM, returns -1.
  If n is ZIFILE or ZRFILE, then Kermit reads from the command, otherwise
  Kermit writes to the command.  Returns 0 on error, 1 on success.

int
zxpand(fn) char *fn;
  OBSOLETE!  Replaced by nzxpand(), q.v.

int
zxrewind()
  Returns the number of files returned by the most recent zxpand call,
  and resets the list to the beginning so the next znext() call returns the
  first file.  Returns -1 if zxpand has not yet been called.  If this function
  is available, ZXREWIND should be defined; otherwise it should not be
  referenced.

int
xsystem(cmd) char *cmd;
  Executes the system command without redirecting any of its i/o, similar
  (well, identical) to system() in Unix.  But before passing the command to
  the system, xsystem() ensures that all privileges are turned off, so that
  the system command will execute in ordinary unprivileged user mode.

B.1.2 IKSD Functions

These must be implemented in any C-Kermit version that is to be installed as
an Internet Kermit Service Daemon (IKSD).  IKSD is expected to be started by
the Internet Daemon (e.g. inetd) with its standard i/o redirected to the
incoming connection.

int ckxanon;
  Nonzero if anonymous logins allowed.

extern int inserver;
  Nonzero if started in IKSD mode.

extern int isguest;
  Nonzero if IKSD and user logged in anonymously.

extern char * homdir;
  Pointer to user's home directory.

extern char * anonroot;
  Pointer to file-system root for anonymous users.

Existing functions must make "if (inserver && isguest)" checks for actions
that would not be legal for guests: zdelete(), zrmdir(), zprint(), zmail(),
etc.

int
zvuser(name) char * name;
  Verifies that user "name" exists and is allowed to log in.  If the name is
  "ftp" or "anonymous" and ckxanon != 0, a guest login is set up.  Returns 0
  if user not allowed to log in, nonzero if user may log in.

zvpass(string) char * string;
  Verifies password of the user from the most recent zvuser() call.  Returns
  nonzero if password is valid for user, 0 if it isn't.  Makes any appropriate
  system log entries (IKSD logins, failed login attempts, etc).  If password
  is valid, logs the user in as herself (if real user), or sets up restricted
  anonymous access if user is guest (e.g. changes file-system root to
  anonroot and sets isguest = 1).

void
zsyslog()
  Begins any desired system logging of an IKSD session.

void
zvlogout()
  Terminates an IKSD session.  In most cases this is simply a wrapper for
  exit() or doexit(), with some system logging added.

B.1.3 Security/Privilege Functions (all)

These functions are used by C-Kermit to adapt itself to operating systems
where the program can be made to run in a "privileged" mode.  C-Kermit
should NOT read and write files or start subprocesses as a privileged program.
This would present a serious threat to system security.  The security package
has been installed to prevent such security breaches by turning off the
program's special privileges at all times except when they are needed.

In UNIX, the only need Kermit has for privileged status is access to the UUCP
lockfile directory, in order to read, create, and destroy lockfiles, and to
open communication devices that are normally protected against the user.
Therefore, privileges should only be enabled for these operations and disabled
at all other times.  This relieves the programmer of the responsibility of
putting expensive and unreliable access checks around every file access and
subprocess creation.

Strictly speaking, these functions are not required in all C-Kermit
implementations, because their use (so far, at least) is internal to the group
3 modules.  However, they should be included in all C-Kermit implementations
for operating systems that support the notion of a privileged program (UNIX,
RSTS/E, what else?).

int
priv_ini()
  Determine whether the program is running in privileged status.  If so,
  turn off the privileges, in such a way that they can be turned on again
  when needed.  Called from sysinit() at program startup time.  Returns:
    0 on success
    nonzero on failure, in which case the program should halt immediately.

int
priv_on()
  If the program is not privileged, this function does nothing.  If the
  program is privileged, this function returns it to privileged status.
  priv_ini() must have been called first.  Returns:
    0 on success
    nonzero on failure

int
priv_off()
  Turns privileges off (if they are on) in such a way that they can be
  turned back on again.  Returns:
    0 on success
    nonzero on failure

int
priv_can()
  Turns privileges off in such a way that they cannot be turned back on.
  Returns:
    0 on success
    nonzero on failure

int
priv_chk()
  Attempts to turns privileges off in such a way that they can be turned on
  again later.  Then checks to make sure that they were really turned off.
  If they were not really turned off, then they are cancelled permanently.
  Returns:
    0 on success
    nonzero on failure

B.2.  Console-Related Functions.

These relate to the program's "console", or controlling terminal, i.e. the
terminal that the user is logged in on and types commands at, or on a PC or
workstation, the actual keyboard and screen.

int
conbin(esc) char esc;
  Puts the console into "binary" mode, so that Kermit's command parser can
  control echoing and other treatment of characters that the user types.
  esc is the character that will be used to get Kermit's attention during
  packet mode; puts this in a global place.  Sets the ckxech variable.
  Returns:
  -1 on error.
   0 on success.

int
concb(esc) char esc;
  Put console in "cbreak" (single-character wakeup) mode.  That is, ensure
  that each console character is available to the program immediately when the
  user types it.  Otherwise just like conbin().  Returns:
  -1 on error.
   0 on success.

int
conchk()
  Returns a number, 0 or greater, the number of characters waiting to be read
  from the console, i.e. the number of characters that the user has typed that
  have not been read yet.

long
congspd();
  Returns the speed ("baud rate") of the controlling terminal, if known,
  otherwise -1L.

int
congks(timo) int timo;
  Get Keyboard Scancode.  Reads a keyboard scan code from the physical console
  keyboard.  If the timo parameter is greater than zero, then times out and
  returns -2 if no character appears within the given number of seconds.  Upon
  any other kind of error, returns -1.  Upon success returns a scan code,
  which may be any positive integer.  For situations where scan codes cannot
  be read (for example, when an ASCII terminal is used as the job's
  controlling terminal), this function is identical to coninc(), i.e. it
  returns an 8-bit character value.  congks() is for use with workstations
  whose keyboards have Alternate, Command, Option, and similar modifier keys,
  and Function keys that generate codes greater than 255.

int
congm()
  Console get modes.  Gets the current console terminal modes and saves them
  so that conres() can restore them later.  Returns 1 if it got the modes OK,
  0 if it did nothing (e.g. because Kermit is not connected with any terminal),
  -1 on error.

int
coninc(timo) int timo;
  Console Input Character.  Reads a character from the console.  If the timo
  parameter is greater than zero, then coninc() times out and returns -2 if no
  character appears within the given number of seconds.  Upon any other kind
  of error, returns -1.  Upon success, returns the character itself, with a
  value in the range 0-255 decimal.

VOID
conint(f,s) SIGTYP (*f)(), (*s)();
  Sets the console to generate an interrupt if the user types a keyboard
  interrupt character, and to transfer control the signal-handling function f.
  For systems with job control, s is the address of the function that suspends
  the job.  Sets the global variable "backgrd" to zero if Kermit is running in
  the foreground, and to nonzero if Kermit is running in the background.
  See ckcdeb.h for the definition of SIGTYP.  No return value.

VOID
connoi()
  Console no interrupts.  Disable keyboard interrupts on the console.
  No return value.

int
conoc(c) char c;
  Write character c to the console terminal.  Returns:
  0 on failure, 1 on success.

int
conol(s) char *s;
  Write string s to the console.  Returns -1 on error, 0 or greater on
  success.

int
conola(s) char *s[]; {
  Write an array of strings to the console.  Returns -1 on error, 0 or greater
  on success.

int
conoll(s) char *s;
  Write string s to the console, followed by the necessary line termination
  characters to put the console cursor at the beginning of the next line.
  Returns -1 on error, 0 or greater on success.

int
conres()
  Restore the console terminal to the modes obtained by congm().  Returns:
  -1 on error, 0 on success.

int
conxo(x,s) int x; char *s;
  Write x characters from string s to the console.  Returns 0 or greater on
  success, -1 on error.

char *
conkbg();
  Returns a pointer to the designator of the console keyboard type.
  For example, on a PC, this function would return "88", "101", etc.
  Upon failure, returns a pointer to the empty string.


B.3 - Communication Device Functions

The communication device is the device used for terminal emulation and file
transfer.  It may or may not be the same device as the console, and it may
or may not be a terminal device (it could also be a network device).  For
brevity, the communication device is referred to here as the "tty".  When the
communication device is the same as the console device, Kermit is said to be
in remote mode.  When the two devices are different, Kermit is in local mode.

int
ttchk()
  Returns the number of characters that have arrived at the communication
  device but have not yet been read by ttinc(), ttinl(), and friends.  If
  communication input is buffered (and it should be), this is the sum of the
  number of unread characters in Kermit's buffer PLUS the number of unread
  characters in the operating system's internal buffer.  The call must be
  nondestructive and nonblocking, and as inexpensive as possible.
  Returns:
   0 or greater on success,
   0 in case of internal error,
  -1 or less when it determines the  connection has been broken,
     or there is no connection.
  That is, a negative return from ttchk() should reliably indicate that there
  is no usable connection.  Furthermore, ttchk