vlib: add recursive macro expander to debug cli

All of the pieces have been sitting around for years.

Added several debug CLI commands:

"define <variable-name> <value>"
"undefine <variable-name>"
"show macro [noeval]"
"echo <whatever>"

Macros may refer to other macros. To defer evaluation:
"define foo \$(bar)" or some such.

The macro evaluator is not smart about "define foo \$(foo)" or more
complicated circular definitions, so don't do that.

Environment variables are available, simply use $<name-of-environment-vbl>

The macro expander has a table of (overrideable) builtin names, which
are evaluated by calling functions.

Simple example:

echo $USER
define ip1 192.168.1.1/24
define ip2 192.168.2.1/24

loop create
loop create
set int ip address loop0 $ip1
set int ip address loop1 $ip2
show int addr
show macro
undefine ip1
undefine ip2

Type: feature

Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: I08a800647bac573d8ae3cfd75c40061d41c5f976

6 files changed, 237 insertions, 37 deletions

diff --git a/src/vat/main.c b/src/vat/main.c
index 139594944d2..a6779c591ce 100644
--- a/src/vat/main.c
+++ b/src/vat/main.c
@@ -208,14 +208,14 @@ init_error_string_table (vat_main_t * vam)
 }
 
 static i8 *
-eval_current_file (macro_main_t * mm, i32 complain)
+eval_current_file (clib_macro_main_t * mm, i32 complain)
 {
   vat_main_t *vam = &vat_main;
   return ((i8 *) format (0, "%s%c", vam->current_file, 0));
 }
 
 static i8 *
-eval_current_line (macro_main_t * mm, i32 complain)
+eval_current_line (clib_macro_main_t * mm, i32 complain)
 {
   vat_main_t *vam = &vat_main;
   return ((i8 *) format (0, "%d%c", vam->input_line_number, 0));
diff --git a/src/vat/vat.h b/src/vat/vat.h
index bcaddfe0126..3e9476f0a66 100644
--- a/src/vat/vat.h
+++ b/src/vat/vat.h
@@ -158,7 +158,7 @@ typedef struct
   uword *help_by_name;
 
   /* macro table */
-  macro_main_t macro_main;
+  clib_macro_main_t macro_main;
 
   /* Errors by number */
   uword *error_string_by_error_number;
diff --git a/src/vlib/unix/cli.c b/src/vlib/unix/cli.c
index b553e12bac2..6b02fdf9bf5 100644
--- a/src/vlib/unix/cli.c
+++ b/src/vlib/unix/cli.c
@@ -61,6 +61,7 @@
 #include <limits.h>
 #include <netinet/tcp.h>
 #include <math.h>
+#include <vppinfra/macros.h>
 
 /** ANSI escape code. */
 #define ESC "\x1b"
@@ -491,6 +492,10 @@ typedef struct
 
   /** List of new sessions */
   unix_cli_new_session_t *new_sessions;
+
+  /* Macro expander */
+  clib_macro_main_t macro_main;
+
 } unix_cli_main_t;
 
 /** CLI global state */
@@ -2563,6 +2568,23 @@ more:
       int rv __attribute__ ((unused)) = write (um->log_fd, lv, vec_len (lv));
     }
 
+  /* Run the command through the macro processor */
+  if (vec_len (cf->current_command))
+    {
+      u8 *expanded;
+      vec_validate (cf->current_command, vec_len (cf->current_command));
+      cf->current_command[vec_len (cf->current_command) - 1] = 0;
+      /* The macro expander expects proper C-strings, not vectors */
+      expanded = (u8 *) clib_macro_eval (&cm->macro_main,
+					 (i8 *) cf->current_command,
+					 1 /* complain */ );
+      /* Macro processor NULL terminates the return */
+      _vec_len (expanded) -= 1;
+      vec_reset_length (cf->current_command);
+      vec_append (cf->current_command, expanded);
+      vec_free (expanded);
+    }
+
   /* Build an unformat structure around our command */
   unformat_init_vector (&input, cf->current_command);
 
@@ -2896,6 +2918,8 @@ unix_cli_file_add (unix_cli_main_t * cm, char *name, int fd)
   cf->clib_file_index = clib_file_add (fm, &template);
   cf->output_vector = 0;
   cf->input_vector = 0;
+  vec_validate (cf->current_command, 0);
+  _vec_len (cf->current_command) = 0;
 
   vlib_start_process (vm, n->runtime_index);
 
@@ -3906,6 +3930,123 @@ VLIB_CLI_COMMAND (cli_unix_wait_cmd, static) = {
 /* *INDENT-ON* */
 
 static clib_error_t *
+echo_cmd (vlib_main_t * vm,
+	  unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  unformat_input_t _line_input, *line_input = &_line_input;
+
+  /* Get a line of input. */
+  if (!unformat_user (input, unformat_line_input, line_input))
+    {
+      vlib_cli_output (vm, "");
+      return 0;
+    }
+
+  vlib_cli_output (vm, "%v", line_input->buffer);
+
+  unformat_free (line_input);
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (cli_unix_echo_cmd, static) = {
+  .path = "echo",
+  .short_help = "echo <rest-of-line>",
+  .function = echo_cmd,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+define_cmd_fn (vlib_main_t * vm,
+	       unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  u8 *macro_name;
+  unformat_input_t _line_input, *line_input = &_line_input;
+  unix_cli_main_t *cm = &unix_cli_main;
+  clib_error_t *error;
+
+  if (!unformat (input, "%s", &macro_name))
+    return clib_error_return (0, "missing variable name...");
+
+  /* Remove white space */
+  (void) unformat (input, "");
+
+  /* Get a line of input. */
+  if (!unformat_user (input, unformat_line_input, line_input))
+    {
+      error = clib_error_return (0, "missing value for '%s'...", macro_name);
+      vec_free (macro_name);
+      return error;
+    }
+  /* the macro expander expects c-strings, not vectors... */
+  vec_add1 (line_input->buffer, 0);
+  clib_macro_set_value (&cm->macro_main, (char *) macro_name,
+			(char *) line_input->buffer);
+  vec_free (macro_name);
+  unformat_free (line_input);
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (define_cmd, static) = {
+  .path = "define",
+  .short_help = "define <variable-name> <value>",
+  .function = define_cmd_fn,
+};
+
+/* *INDENT-ON* */
+
+static clib_error_t *
+undefine_cmd_fn (vlib_main_t * vm,
+		 unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  u8 *macro_name;
+  unix_cli_main_t *cm = &unix_cli_main;
+
+  if (!unformat (input, "%s", &macro_name))
+    return clib_error_return (0, "missing variable name...");
+
+  if (clib_macro_unset (&cm->macro_main, (char *) macro_name))
+    vlib_cli_output (vm, "%s wasn't set...", macro_name);
+
+  vec_free (macro_name);
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (undefine_cmd, static) = {
+  .path = "undefine",
+  .short_help = "undefine <variable-name>",
+  .function = undefine_cmd_fn,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
+show_macro_cmd_fn (vlib_main_t * vm,
+		   unformat_input_t * input, vlib_cli_command_t * cmd)
+{
+  unix_cli_main_t *cm = &unix_cli_main;
+  int evaluate = 1;
+
+  if (unformat (input, "noevaluate %=", &evaluate, 0))
+    ;
+  else if (unformat (input, "noeval %=", &evaluate, 0))
+    ;
+
+  vlib_cli_output (vm, "%U", format_clib_macro_main, &cm->macro_main,
+		   evaluate);
+  return 0;
+}
+
+/* *INDENT-OFF* */
+VLIB_CLI_COMMAND (show_macro, static) = {
+  .path = "show macro",
+  .short_help = "show macro [noevaluate]",
+  .function = show_macro_cmd_fn,
+};
+/* *INDENT-ON* */
+
+static clib_error_t *
 unix_cli_init (vlib_main_t * vm)
 {
   unix_cli_main_t *cm = &unix_cli_main;
@@ -3913,7 +4054,7 @@ unix_cli_init (vlib_main_t * vm)
   /* Breadcrumb to indicate the new session process
    * has not been started */
   cm->new_session_process_node_index = ~0;
-
+  clib_macro_init (&cm->macro_main);
   return 0;
 }
 
diff --git a/src/vppinfra/macros.c b/src/vppinfra/macros.c
index 6649277d897..bc6df55b39d 100644
--- a/src/vppinfra/macros.c
+++ b/src/vppinfra/macros.c
@@ -1,9 +1,9 @@
 /*
-  macros.c - a simple macro expander
-
-  Copyright (c) 2010, 2014 Cisco and/or its affiliates.
-
-  * Licensed under the Apache License, Version 2.0 (the "License");
+ * macros.c - a simple macro expander
+ *
+ *  Copyright (c) 2010-2020 Cisco and/or its affiliates.
+ *
+ * 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:
  *
@@ -28,10 +28,10 @@ macro_isalnum (i8 c)
 }
 
 static i8 *
-builtin_eval (macro_main_t * mm, i8 * varname, i32 complain)
+builtin_eval (clib_macro_main_t * mm, i8 * varname, i32 complain)
 {
   uword *p;
-  i8 *(*fp) (macro_main_t *, i32);
+  i8 *(*fp) (clib_macro_main_t *, i32);
 
   p = hash_get_mem (mm->the_builtin_eval_hash, varname);
   if (p == 0)
@@ -41,7 +41,7 @@ builtin_eval (macro_main_t * mm, i8 * varname, i32 complain)
 }
 
 int
-clib_macro_unset (macro_main_t * mm, char *name)
+clib_macro_unset (clib_macro_main_t * mm, char *name)
 {
   hash_pair_t *p;
   u8 *key, *value;
@@ -61,7 +61,7 @@ clib_macro_unset (macro_main_t * mm, char *name)
 }
 
 int
-clib_macro_set_value (macro_main_t * mm, char *name, char *value)
+clib_macro_set_value (clib_macro_main_t * mm, char *name, char *value)
 {
   u8 *key_copy, *value_copy;
   int rv;
@@ -76,7 +76,7 @@ clib_macro_set_value (macro_main_t * mm, char *name, char *value)
 }
 
 i8 *
-clib_macro_get_value (macro_main_t * mm, char *name)
+clib_macro_get_value (clib_macro_main_t * mm, char *name)
 {
   uword *p;
 
@@ -92,7 +92,7 @@ clib_macro_get_value (macro_main_t * mm, char *name)
  * looks up $foobar in the variable table.
  */
 i8 *
-clib_macro_eval (macro_main_t * mm, i8 * s, i32 complain)
+clib_macro_eval (clib_macro_main_t * mm, i8 * s, i32 complain)
 {
   i8 *rv = 0;
   i8 *varname, *varvalue;
@@ -189,7 +189,7 @@ clib_macro_eval (macro_main_t * mm, i8 * s, i32 complain)
  * looks up $foobar in the variable table.
  */
 i8 *
-clib_macro_eval_dollar (macro_main_t * mm, i8 * s, i32 complain)
+clib_macro_eval_dollar (clib_macro_main_t * mm, i8 * s, i32 complain)
 {
   i8 *s2;
   i8 *rv;
@@ -201,14 +201,14 @@ clib_macro_eval_dollar (macro_main_t * mm, i8 * s, i32 complain)
 }
 
 void
-clib_macro_add_builtin (macro_main_t * mm, char *name, void *eval_fn)
+clib_macro_add_builtin (clib_macro_main_t * mm, char *name, void *eval_fn)
 {
   hash_set_mem (mm->the_builtin_eval_hash, name, (uword) eval_fn);
 }
 
 #ifdef CLIB_UNIX
 static i8 *
-eval_hostname (macro_main_t * mm, i32 complain)
+eval_hostname (clib_macro_main_t * mm, i32 complain)
 {
   char tmp[128];
   if (gethostname (tmp, sizeof (tmp)))
@@ -218,7 +218,7 @@ eval_hostname (macro_main_t * mm, i32 complain)
 #endif
 
 void
-clib_macro_init (macro_main_t * mm)
+clib_macro_init (clib_macro_main_t * mm)
 {
   if (mm->the_builtin_eval_hash != 0)
     {
@@ -235,7 +235,7 @@ clib_macro_init (macro_main_t * mm)
 }
 
 void
-clib_macro_free (macro_main_t * mm)
+clib_macro_free (clib_macro_main_t * mm)
 {
   hash_pair_t *p;
   u8 **strings_to_free = 0;
@@ -257,6 +257,62 @@ clib_macro_free (macro_main_t * mm)
   hash_free (mm->the_value_table_hash);
 }
 
+typedef struct
+{
+  u8 *name;
+  u8 *value;
+} name_sort_t;
+
+static int
+name_compare (void *a1, void *a2)
+{
+  name_sort_t *ns1 = a1;
+  name_sort_t *ns2 = a2;
+
+  return strcmp ((char *) ns1->name, (char *) ns2->name);
+}
+
+
+u8 *
+format_clib_macro_main (u8 * s, va_list * args)
+{
+  clib_macro_main_t *mm = va_arg (*args, clib_macro_main_t *);
+  int evaluate = va_arg (*args, int);
+  hash_pair_t *p;
+  name_sort_t *nses = 0, *ns;
+  int i;
+
+  /* *INDENT-OFF* */
+  hash_foreach_pair (p, mm->the_value_table_hash,
+  ({
+    vec_add2 (nses, ns, 1);
+    ns->name = (u8 *)(p->key);
+    ns->value = (u8 *)(p->value[0]);
+  }));
+  /* *INDENT-ON* */
+
+  if (vec_len (nses) == 0)
+    return s;
+
+  vec_sort_with_function (nses, name_compare);
+
+  for (i = 0; i < vec_len (nses); i++)
+    {
+      s = format (s, "%-20s", nses[i].name);
+      if (evaluate == 0)
+	s = format (s, "%s\n", nses[i].value);
+      else
+	{
+	  u8 *rv = (u8 *) clib_macro_eval_dollar (mm, (i8 *) nses[i].name,
+						  0 /* no complain */ );
+	  s = format (s, "%s\n", rv);
+	  vec_free (rv);
+	}
+    }
+  return s;
+}
+
+
 /*
  * fd.io coding-style-patch-verification: ON
  *
diff --git a/src/vppinfra/macros.h b/src/vppinfra/macros.h
index 5c2e7033f8d..54ceda7016b 100644
--- a/src/vppinfra/macros.h
+++ b/src/vppinfra/macros.h
@@ -1,9 +1,9 @@
 /*
-  macros.h - definitions for a simple macro expander
-
-  Copyright (c) 2010, 2014 Cisco and/or its affiliates.
-
-  * Licensed under the Apache License, Version 2.0 (the "License");
+ * macros.h - definitions for a simple macro expander
+ *
+ *  Copyright (c) 2010-2020 Cisco and/or its affiliates.
+ *
+ * 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:
  *
@@ -32,16 +32,19 @@ typedef struct
 {
   uword *the_builtin_eval_hash;
   uword *the_value_table_hash;
-} macro_main_t;
-
-int clib_macro_unset (macro_main_t * mm, char *name);
-int clib_macro_set_value (macro_main_t * mm, char *name, char *value);
-void clib_macro_add_builtin (macro_main_t * mm, char *name, void *eval_fn);
-i8 *clib_macro_get_value (macro_main_t * mm, char *name);
-i8 *clib_macro_eval (macro_main_t * mm, i8 * s, i32 complain);
-i8 *clib_macro_eval_dollar (macro_main_t * mm, i8 * s, i32 complain);
-void clib_macro_init (macro_main_t * mm);
-void clib_macro_free (macro_main_t * mm);
+} clib_macro_main_t;
+
+int clib_macro_unset (clib_macro_main_t * mm, char *name);
+int clib_macro_set_value (clib_macro_main_t * mm, char *name, char *value);
+void clib_macro_add_builtin (clib_macro_main_t * mm, char *name,
+			     void *eval_fn);
+i8 *clib_macro_get_value (clib_macro_main_t * mm, char *name);
+i8 *clib_macro_eval (clib_macro_main_t * mm, i8 * s, i32 complain);
+i8 *clib_macro_eval_dollar (clib_macro_main_t * mm, i8 * s, i32 complain);
+void clib_macro_init (clib_macro_main_t * mm);
+void clib_macro_free (clib_macro_main_t * mm);
+
+format_function_t format_clib_macro_main;
 
 #endif /* included_macros_h */
 
diff --git a/src/vppinfra/test_macros.c b/src/vppinfra/test_macros.c
index cf6172ab1f1..f130604d691 100644
--- a/src/vppinfra/test_macros.c
+++ b/src/vppinfra/test_macros.c
@@ -16,12 +16,12 @@
 
 #include <vppinfra/macros.h>
 
-macro_main_t macro_main;
+clib_macro_main_t clib_macro_main;
 
 int
 test_macros_main (unformat_input_t * input)
 {
-  macro_main_t *mm = &macro_main;
+  clib_macro_main_t *mm = &clib_macro_main;
 
   clib_macro_init (mm);