ckcplm.doc

linux终端仿真程序

int
zshcmd(s) char *s;
  s contains to pointer to a command to be executed by the host computer's
  shell, command parser, or operating system.  If the system allows the user
  to choose from a variety of command processors (shells), then this function
  should employ the user's preferred shell.  If possible, the user's job
  (environment, process, etc) should be set up to catch keyboard interruption
  signals to allow the user to halt the system command and return to Kermit.
  The command must run in ordinary, unprivileged user mode.
  If possible, this function should return -1 on failure to start the command,
  or else it should return 1 if the command succeeded and 0 if it failed.

int
zsyscmd(s) char *s;  *NEW*
  s contains to pointer to a command to be executed by the host computer's
  shell, command parser, or operating system.  If the system allows the user
  to choose from a variety of command processors (shells), then this function
  should employ the system standard shell (e.g. /bin/sh for Unix), so that the
  results will always be the same for everybody.  If possible, the user's job
  (environment, process, etc) should be set up to catch keyboard interruption
  signals to allow the user to halt the system command and return to Kermit.
  The command must run in ordinary, unprivileged user mode.
  If possible, this function should return -1 on failure to start the command,
  or else it should return 1 if the command succeeded and 0 if it failed.

int
zsinl(n,s,x) int n, x; char *s;  *NEW*
  Reads a line from file number n.
  Writes the line into the address s provided by the caller.
  Writing terminates when newline is read, but with newline discarded.
  Writing also terminates upon EOF or if length x is exhausted.
  Returns:
  -1 on EOF or error.
   0 on success.

int
zsout(n,s) int n; char *s;
  Writes the string s out to file number n.  Returns:
  -1 on failure.
   0 on success.

int
zsoutl(n,s) int n; char *s;
  Writes the string s out to file number n and adds a line (record) terminator 
  (boundary) appropriate for the system and the file format.
  Returns:
  -1 on failure.
   0 on success.

int
zsoutx(n,s,x) int n, x; char *s;
  Writes exactly x characters from string s to file number n.  If s has
  fewer than x characters, then the entire string s is written.  Returns:
  -1 on error.
  >= 0 on success, the number of characters actually written.

int
zstime(f,yy,x) char *f; struct zattr *yy; int x;  *NEW*
  Sets the creation date of an existing file, or compares a file's creation
  date with a given date.  Call with:
  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 the date.
  x  = is a function code: 0 means to set the file's creation date as given.
       1 means compare the given date with the file creation 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;  *NEW*
  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.

*NEW* (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;
  Expands a wildcard string into an array of strings.
  Returns the number of files that match fn1, with data structures set up
  so that first filename (if any) will be returned by the next znext() call.
  If no files match, or if there is any kind of error, zxpand returns 0.

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.1.5 Security/Privilege Functions (all *NEW*)

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

int
priv_chk()  *NEW*
  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();   *NEW*
  Returns the speed ("baud rate") of the controlling terminal, if known,
  otherwise -1L.

int
congks(timo) int timo;   *NEW*
  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)();  *NEW*
  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();  *NEW*
  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.