1 files changed, 198 insertions, 0 deletions
diff --git a/sys/libc/cprcon.c b/sys/libc/cprcon.c
new file mode 100644
index 00000000..c0534a60
--- /dev/null
+++ b/sys/libc/cprcon.c
@@ -0,0 +1,198 @@
+/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+*/
+
+#define import_spp
+#define	import_libc
+#define	import_xnames
+#define	import_stdio
+#define	import_prstat
+#include <iraf.h>
+
+
+/* CPRCON -- Connected subprocesses.  A connected subprocess is an active filter
+** which communicates with the parent process via an input stream and an output
+** stream.  A connected subprocess is logically equivalent to the user terminal.
+** The set of useful operations thus far identified for connected subprocesses
+** are open and close, read and write, and signal (interrupt).  The read and
+** write operations are provided by interfacing the IPC channels from the
+** subprocess to FIO.  The remaining operations are peculiar to connected
+** subprocesses and are summarized below.
+**
+**		  pid =	c_propen (process, in, out)
+**		stat = c_prclose (pid)
+**		stat = c_prstati (pid, param)
+**		      c_prsignal (pid, signal)
+**		       c_prredir (pid, stream, new_fd)
+**		       c_prchdir (pid, newdir)
+**		      c_prenvset (pid, envvar, valuestr)
+**
+** A connected subprocess must be opened either with c_propen or with the low
+** level procedure PROPCPR (the latter does not require that the subprocess
+** recognize the standard IPC protocol).  An idle subprocess may be closed
+** with c_prclose, which not only closes the process but releases important
+** system resources.  The c_prsignal procedure raises the X_INT (interrupt)
+** exception in a subprocess, generally following receipt of a user interrupt
+** by the parent process.  Redirection of the child's standard i/o streams
+** is provided by c_prredir.  Finally, c_prchdir and c_prenvsets are used
+** to update the current directory and environment in child processes.
+*/
+
+
+/* C_PROPEN -- Open a connected subprocess, i.e., spawn the subprocess and
+** connect the two IPC channels connecting the child and parent to FIO.
+** The FIO streams may subsequently be opened for C style STDIO by calling
+** FDOPEN, if desired.  The C_PROPEN procedure sends the current environment
+** and working directory to the child as part of process startup.  The process
+** id (PID) of the child process is returned as the function value.  This
+** magic integer value uniquely identifies the process to the system.
+**
+** N.B.: opening a child process leaves the child in the IRAF Main interpreter
+** loop, with the child waiting for a command from the parent.  A child process
+** is capabable of performing an arbitrary number of "tasks".  To get the child
+** to run a task, the parent must write the name of the task to the OUT stream,
+** then read from the IN stream, responding to all queries from the child until
+** "bye" or "error" is received.
+*/
+unsigned int
+c_propen (
+  char	*process,		/* filename of executable process	*/
+  int	*in,			/* FD for reading from child		*/
+  int	*out			/* FD for writing to child		*/
+)
+{
+	register unsigned int pid;
+	XINT  x_in = *in, x_out = *out;
+
+	iferr (pid = (unsigned int) PROPEN (c_sppstr(process), &x_in, &x_out))
+	    return (NULL);
+	else {
+	    *in = (int) x_in;
+	    *out = (int) x_out;
+	    FDTOFP(*in)->_fflags |= _FIPC;
+	    return (pid);
+	}
+}
+
+
+/* C_PRCLOSE -- Close a connected subprocess.  The "bye" command is sent to
+** the child, commanding it to shut down, and when the task terminates the
+** exit status is returned as the function value.  The C_PRCLOSE procedure
+** must be called at process termination to free system resources.  C_PRCLOSE
+** is automatically called by the system if error recovery takes place in
+** the parent process.  Calling C_PRCLOSE is equivalent to individually
+** closing the IN and OUT streams to the subprocess (which is what happens
+** if system error recovery takes place).
+*/
+int
+c_prclose (
+  unsigned int pid		/* process id returned by C_PROPEN	*/
+)
+{
+	XINT  x_pid = pid;
+
+	return (PRCLOSE (&x_pid));
+}
+
+
+/* C_PRSTATI -- Get status on a connected subprocess.  See <libc/prstat.h>
+** for a list of parameters.
+*/
+int
+c_prstati (
+  int	pid,			/* process id of process		*/
+  int	param			/* parameter for which value is ret	*/
+)
+{
+	XINT  x_pid = pid, x_param = param;
+
+	return (PRSTATI (&x_pid, &x_param));
+}
+
+
+/* C_PRSIGNAL -- Send a signal, i.e., asynchronous interrupt, to a connected
+** child process.  Currently only the X_INT signal is implemented, and the
+** second argument is not used.  The value X_INT should nontheless be passed.
+*/
+int
+c_prsignal (
+  unsigned pid,			/* process id of process		*/
+  int	signal			/* not used at present			*/
+)
+{
+	XINT  x_pid = pid,  x_signal = signal;
+
+	iferr (PRSIGNAL (&x_pid, &x_signal))
+	    return (ERR);
+	else
+	    return (OK);
+}
+
+
+/* C_PRREDIR -- Redirect one of the standard i/o streams of the child process.
+** By default the child inherits the standard i/o streams of the parent at
+** C_PROPEN time, i.e., the STDOUT of the child is connected to the STDOUT of
+** the parent.  If the parent's STDOUT is subsequently redirected, e.g., with
+** C_FREDIR, the child's output will be redirected as well.  More commonly
+** one or more of the child's streams will be explicitly redirected with
+** C_PRREDIR.  Such redirection remains in effect for the life of the
+** process, i.e., until process termination via C_PRCLOSE or until another
+** call to C_PRREDIR.  Note that often this is not what is desired, rather,
+** one wishes to redirect a stream for the duration of a task running within
+** the process.  For this reason it is recommended that C_PRREDIR be called
+** for each standard stream (it costs almost nothing) immediately prior to
+** task execution.
+**
+** Example:
+**		fp = fopen ("tmp$spoolfile", "w");
+**		if (c_prredir (pid, STDOUT, fileno(fp)) == ERR)
+**			...
+*/
+int
+c_prredir (
+  unsigned pid,			/* process id of child			*/
+  int	stream,			/* child's stream to be redirected	*/
+  int	new_fd			/* FD of opened file in parent		*/
+)
+{
+	XINT  x_pid = pid, x_stream = stream, x_new_fd = new_fd;
+
+	iferr (PRREDIR (&x_pid, &x_stream, &x_new_fd))
+	    return (ERR);
+	else
+	    return (OK);
+}
+
+
+/* C_PRCHDIR -- Change the current working directory of a child process.
+** If pid=NULL all currently connected processes are updated.  May only
+** be called when the child process is idle.
+*/
+int
+c_prchdir (
+  int	pid,
+  char	*newdir
+)
+{
+	XINT  x_pid = pid;
+
+	return (PRCHDIR (&x_pid, c_sppstr (newdir)));
+}
+
+
+/* C_PRENVSET -- Transmit a set environment directive to the child process.
+** If pid=NULL all currently connected processes are updated.  May only
+** be called when the child process is idle.
+*/
+int
+c_prenvset (
+  int	pid,
+  char	*envvar, 
+  char  *value
+)
+{
+	XCHAR  spp_value[SZ_LINE];
+	XINT   x_pid = pid;
+
+	c_strupk (value, spp_value, SZ_LINE);
+	return (PRENVSET (&x_pid, c_sppstr (envvar), spp_value));
+}