* Fixed: Yang patterns: \n and other non-printable characters were broken

* Example: Clixon interpereted them two characters: `\\ n` instead of ascii 10

CHANGELOG.md

@@ -56,6 +56,8 @@ Users may have to change how they access the system
 
 ### Corrected Bugs
 
+* Fixed: Yang patterns: \n and other non-printable characters were broken
+  * Example: Clixon interpereted them two characters: `\\ n` instead of ascii 10
 * Fixed: The auto-cli identityref did not expand identities in grouping/usecases properly.
 * Fixed: [OpenConfig BGP afi-safi and when condition issues #249](https://github.com/clicon/clixon/issues/249)
   * YANG when was not properly implemented for default values

lib/clixon/clixon_string.h

@@ -100,6 +100,8 @@ int    xml_chardata_encode(char **escp, const char *fmt, ...);
 #endif
 int    xml_chardata_cbuf_append(cbuf *cb, char *str);
 int    uri_percent_decode(char *enc, char **str);
+int    nonprint_encode(char *orig, char **encp);
+
 const char *clicon_int2str(const map_str2int *mstab, int i);
 int    clicon_str2int(const map_str2int *mstab, char *str);
 int    clicon_str2int_search(const map_str2int *mstab, char *str, int upper);

lib/src/clixon_string.c

@@ -646,6 +646,83 @@ uri_str2cvec(char  *string,
     goto done;
 }
 
+/*! Translate \n and others from \\n (two chars) to \n (one char)
+ *
+ * This is needed in yang regex it seems.
+ * It was triggered by eg draft-wwlh-netconf-list-pagination-00 module example-social tagline
+ *       leaf tagline {
+ *         type string {
+ *           length "1..80";
+ *           pattern '.*[\n].*' {
+ *             modifier invert-match;
+ * @param[in]  orig  Original string eg with \\n
+ * @param[out] enc   Encoded string with \n, malloced.
+ *
+ * @see https://www.regular-expressions.info/nonprint.html
+ */
+int
+nonprint_encode(char  *orig, 
+		char **encp)
+{
+    int   retval = -1;
+    char *enc = NULL;
+    int   i;
+    int   j;
+    int   esc = 0;
+    char  c;
+    char  c1;
+
+    if (orig == NULL){
+	clicon_err(OE_UNIX, EINVAL, "orig is NULL");
+	goto done;
+    }
+    /* Encoded string is equal or shorter */
+    if ((enc = malloc(strlen(orig)+1)) == NULL){
+	clicon_err(OE_UNIX, errno, "strdup");
+	goto done;
+    }
+    j = 0;
+    for (i=0; i<strlen(orig); i++){
+	c = orig[i];
+	switch (c){
+	case '\\':
+	    /* Look ahead */
+	    if (i+1 < strlen(orig)){
+		c1 = orig[i+1]; 
+		switch (c1){
+		case 'n':
+		    enc[j++] = '\n';
+		    esc++;
+		    break;
+		case 't':
+		    enc[j++] = '\t';
+		    esc++;
+		    break;
+		case 'r':
+		    enc[j++] = '\r';
+		    esc++;
+		    break;
+		default:
+		    enc[j++] = c;
+		    break;
+		}
+	    }
+	    break;
+	default:
+	    if (esc)
+		esc = 0;		
+	    else
+		enc[j++] = c;
+	    break;
+	}
+    }
+    enc[j++] = '\0';
+    *encp = enc;
+    retval = 0;
+ done:
+    return retval;
+}
+
 /*! Map from int to string using str2int map
  * @param[in] ms   String, integer map
  * @param[in] i    Input integer

lib/src/clixon_yang_parse_lib.c

@@ -1896,6 +1896,18 @@ ys_parse_sub(yang_stmt *ys,
 	    goto done;
 	}
 	break;
+    case Y_PATTERN:{
+	char *s0;
+	char *s1 = NULL;
+	/* Replace \\n with \n */
+	s0 = yang_argument_get(ys);
+	if (nonprint_encode(s0, &s1) < 0)
+	    goto done;
+	yang_argument_set(ys, s1);
+	if (s0)
+	    free(s0);
+	break;
+    }
     case Y_UNKNOWN:{ /* save (optional) argument in ys_cv */
 	if (extra == NULL)
 	    break;

test/test_pattern.sh

@@ -368,6 +368,15 @@ module pattern{
               '[0-9]|25[0-5])$';
          }
       }
+      leaf p47 {
+         description "draft-wwlh-netconf-list-pagination-00 module example-social";
+         type string {
+             length "1..80";
+             pattern '.*[\n].*' {
+               modifier invert-match;
+             }
+         }
+      }
    }
 }
 EOF
@@ -741,6 +750,11 @@ testrun "p$pnr" true '255.149.90.121'
 testrun "p$pnr" true '251.148.80.69'
 testrun "p$pnr" false '248:197.7.89/8'
 
+let pnr=47 # '.*[\n].*
+testrun "p$pnr" true 'Ensure all nights are cold'
+testrun "p$pnr" false 'kalle
foo'
+testrun "p$pnr" false '01234567890123456789012345678901234567890123456789012345678901234567890123456789zzz'
+
 # CLI tests
 new "CLI tests for RFC7950 Sec 9.4.7 ex 2 AB"
 expectpart "$($clixon_cli -1f $cfg -l o set c rfc2 AB)" 0 '^$'