Output pipe functionality

Based on output pipe code in CLIgen
Clixon adaptions include `CLICON_PIPETREE=` variable and a new cli_pipe.c callback file

apps/cli/cli_pipe.c

@@ -0,0 +1,123 @@
+/*
+ *
+  ***** BEGIN LICENSE BLOCK *****
+ 
+  Copyright (C) 2023 Olof Hagsand 
+
+  This file is part of CLIXON.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+  Alternatively, the contents of this file may be used under the terms of
+  the GNU General Public License Version 3 or later (the "GPL"),
+  in which case the provisions of the GPL are applicable instead
+  of those above. If you wish to allow use of your version of this file only
+  under the terms of the GPL, and not to allow others to
+  use your version of this file under the terms of Apache License version 2, 
+  indicate your decision by deleting the provisions above and replace them with
+  the  notice and other provisions required by the GPL. If you do not delete
+  the provisions above, a recipient may use your version of this file under
+  the terms of any one of the Apache License version 2 or the GPL.
+
+  ***** END LICENSE BLOCK *****
+ * 
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "clixon_config.h" /* generated by config & autoconf */
+#endif
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <signal.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <time.h>
+#include <ctype.h>
+
+#include <unistd.h>
+#include <dirent.h>
+#include <syslog.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <sys/param.h>
+#include <sys/mount.h>
+#include <pwd.h>
+
+/* cligen */
+#include <cligen/cligen.h>
+
+/* clicon */
+#include <clixon/clixon.h>
+
+#include "clixon_cli_api.h"
+
+/* Grep pipe output function
+ */
+int
+grep_fn(cligen_handle h,
+        cvec         *cvv,
+        cvec         *argv)
+{
+    int     retval = -1;
+    cbuf   *cb = NULL;
+    cg_var *av;
+    cg_var *cv;
+    char   *name;
+
+    if ((cb = cbuf_new()) == NULL){
+        perror("cbuf_new");
+        goto done;
+    }
+    if (argv && (av = cvec_i(argv, 0)) != NULL){
+        /* First arg is command */
+        //        cprintf(cb, "%s", cv_string_get(av));
+        /* Rest are names of parameters from cvv */
+        av = NULL;
+        while ((av = cvec_each1(argv, av)) != NULL){
+            name = cv_string_get(av);
+            if ((cv = cvec_find_var(cvv, name)) != NULL)
+                cprintf(cb, "%s", cv_string_get(cv));
+        }
+        retval = execl("/usr/bin/grep", "grep", "-e", cbuf_get(cb), (char *) NULL);
+    }
+ done:
+    if (cb)
+        cbuf_free(cb);
+    return retval;
+}
+
+/*! Test cli callback calls cligen_output with output lines as given by function arguments
+ *
+ * This is to generate output to eg cligen_output scrolling
+ * Example:
+ * a, printlines_fn("line1 abc", "line2 def");
+ */
+int
+output_fn(cligen_handle handle,
+          cvec         *cvv,
+          cvec         *argv)
+{
+    cg_var *cv;
+    
+    cv = NULL;
+    while ((cv = cvec_each(argv, cv)) != NULL){
+        cligen_output(stdout, "%s\n", cv_string_get(cv));
+    }
+    return 0;
+}