[PATCH v2 1/2] cmdline: add function to verify valid commands

[Bruce Richardson <bruce.richardson@intel.com>]

The cmdline library cmdline_parse() function parses a command and
executes the action automatically too. The cmdline_valid_buffer function
also uses this function to validate commands, meaning that there is no
function to validate a command as ok without executing it.

To fix this omission, we extract the body of cmdline_parse into a new
static inline function with an extra parameter to indicate whether the
action should be performed or not. Then we create two wrappers around
that - a replacement for the existing cmdline_parse function where the
extra parameter is "true" to execute the command, and a new function
"cmdline_parse_check" which passes the parameter as "false" to perform
cmdline validation only.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
 lib/cmdline/cmdline_parse.c | 20 +++++++++++++++++---
 lib/cmdline/cmdline_parse.h | 17 +++++++++++++++--
 lib/cmdline/version.map     |  3 +++
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/lib/cmdline/cmdline_parse.c b/lib/cmdline/cmdline_parse.c
index 349ec87bd7..b7fdc67ae5 100644
--- a/lib/cmdline/cmdline_parse.c
+++ b/lib/cmdline/cmdline_parse.c
@@ -7,6 +7,7 @@
 #include <stdio.h>
 #include <errno.h>
 #include <string.h>
+#include <stdbool.h>
 
 #include <rte_string_fns.h>
 
@@ -182,8 +183,8 @@ match_inst(cmdline_parse_inst_t *inst, const char *buf,
 }
 
 
-int
-cmdline_parse(struct cmdline *cl, const char * buf)
+static inline int
+__cmdline_parse(struct cmdline *cl, const char *buf, bool call_fn)
 {
 	unsigned int inst_num=0;
 	cmdline_parse_inst_t *inst;
@@ -284,7 +285,8 @@ cmdline_parse(struct cmdline *cl, const char * buf)
 
 	/* call func */
 	if (f) {
-		f(result.buf, cl, data);
+		if (call_fn)
+			f(result.buf, cl, data);
 	}
 
 	/* no match */
@@ -296,6 +298,18 @@ cmdline_parse(struct cmdline *cl, const char * buf)
 	return linelen;
 }
 
+int
+cmdline_parse(struct cmdline *cl, const char *buf)
+{
+	return __cmdline_parse(cl, buf, true);
+}
+
+int
+cmdline_parse_check(struct cmdline *cl, const char *buf)
+{
+	return __cmdline_parse(cl, buf, false);
+}
+
 int
 cmdline_complete(struct cmdline *cl, const char *buf, int *state,
 		 char *dst, unsigned int size)
diff --git a/lib/cmdline/cmdline_parse.h b/lib/cmdline/cmdline_parse.h
index e4d802fff7..6dd210d843 100644
--- a/lib/cmdline/cmdline_parse.h
+++ b/lib/cmdline/cmdline_parse.h
@@ -7,6 +7,8 @@
 #ifndef _CMDLINE_PARSE_H_
 #define _CMDLINE_PARSE_H_
 
+#include <rte_compat.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -149,11 +151,22 @@ typedef cmdline_parse_inst_t *cmdline_parse_ctx_t;
  * argument buf must ends with "\n\0". The function returns
  * CMDLINE_PARSE_AMBIGUOUS, CMDLINE_PARSE_NOMATCH or
  * CMDLINE_PARSE_BAD_ARGS on error. Else it calls the associated
- * function (defined in the context) and returns 0
- * (CMDLINE_PARSE_SUCCESS).
+ * function (defined in the context) and returns the parsed line length (>= 0)
  */
 int cmdline_parse(struct cmdline *cl, const char *buf);
 
+/**
+ * Try to parse a buffer according to the specified context, but do not
+ * perform any function calls if parse is successful.
+ *
+ * The argument buf must ends with "\n\0".
+ * The function returns CMDLINE_PARSE_AMBIGUOUS, CMDLINE_PARSE_NOMATCH or
+ * CMDLINE_PARSE_BAD_ARGS on error and returns the parsed line length (>=0).
+ * on successful parse
+ */
+__rte_experimental
+int cmdline_parse_check(struct cmdline *cl, const char *buf);
+
 /**
  * complete() must be called with *state==0 (try to complete) or
  * with *state==-1 (just display choices), then called without
diff --git a/lib/cmdline/version.map b/lib/cmdline/version.map
index b9bbb87510..fc7fdd6ea4 100644
--- a/lib/cmdline/version.map
+++ b/lib/cmdline/version.map
@@ -81,5 +81,8 @@ EXPERIMENTAL {
 	rdline_get_history_buffer_size;
 	rdline_get_opaque;
 
+	# added in 22.07
+	cmdline_parse_check;
+
 	local: *;
 };
-- 
2.34.1