jshn: add support for namespaces

Can be used to fix variable namespace clashes in library code using jshn

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

1 files changed, 17 insertions, 7 deletions

diff --git a/jshn.c b/jshn.c
index f7a46de..dc002c1 100644
--- a/jshn.c
+++ b/jshn.c
@@ -9,6 +9,9 @@
 
 #define MAX_VARLEN	256
 
+static const char *var_prefix = "";
+static int var_prefix_len = 0;
+
 static int add_json_element(const char *key, json_object *obj);
 
 static int add_json_object(json_object *obj)
@@ -145,8 +148,8 @@ static char *get_keys(const char *prefix)
 {
 	char *keys;
 
-	keys = alloca(strlen(prefix) + sizeof("KEYS_") + 1);
-	sprintf(keys, "KEYS_%s", prefix);
+	keys = alloca(var_prefix_len + strlen(prefix) + sizeof("KEYS_") + 1);
+	sprintf(keys, "%sKEYS_%s", var_prefix, prefix);
 	return getenv(keys);
 }
 
@@ -154,12 +157,15 @@ static void get_var(const char *prefix, const char **name, char **var, char **ty
 {
 	char *tmpname, *varname;
 
-	tmpname = alloca(strlen(prefix) + 1 + strlen(*name) + 1 + sizeof("TYPE_"));
-	sprintf(tmpname, "TYPE_%s_%s", prefix, *name);
-	*var = getenv(tmpname + 5);
+	tmpname = alloca(var_prefix_len + strlen(prefix) + 1 + strlen(*name) + 1 + sizeof("TYPE_"));
+
+	sprintf(tmpname, "%s%s_%s", var_prefix, prefix, *name);
+	*var = getenv(tmpname);
+
+	sprintf(tmpname, "%sTYPE_%s_%s", var_prefix, prefix, *name);
 	*type = getenv(tmpname);
 
-	memcpy(tmpname, "NAME", 4);
+	sprintf(tmpname, "%sNAME_%s_%s", var_prefix, prefix, *name);
 	varname = getenv(tmpname);
 	if (varname)
 		*name = varname;
@@ -238,8 +244,12 @@ int main(int argc, char **argv)
 	bool no_newline = false;
 	int ch;
 
-	while ((ch = getopt(argc, argv, "nr:w")) != -1) {
+	while ((ch = getopt(argc, argv, "p:nr:w")) != -1) {
 		switch(ch) {
+		case 'p':
+			var_prefix = optarg;
+			var_prefix_len = strlen(var_prefix);
+			break;
 		case 'r':
 			return jshn_parse(optarg);
 		case 'w':