json_script: implement json_script_eval_string

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

diff --git a/json_script.c b/json_script.c
index a288214..ba1e498 100644 (file)
--- a/json_script.c
+++ b/json_script.c
@@ -388,15 +388,14 @@ static int json_process_expr(struct json_call *call, struct blob_attr *cur)
        return ret;
 }
 
-static int cmd_add_string(struct json_call *call, const char *pattern)
+static int eval_string(struct json_call *call, struct blob_buf *buf, const char *name, const char *pattern)
 {
-       struct json_script_ctx *ctx = call->ctx;
        char *dest, *next, *str;
        int len = 0;
        bool var = false;
        char c = '%';
 
-       dest = blobmsg_alloc_string_buffer(&ctx->buf, NULL, 1);
+       dest = blobmsg_alloc_string_buffer(buf, name, 1);
        next = alloca(strlen(pattern) + 1);
        strcpy(next, pattern);
 
@@ -435,19 +434,37 @@ static int cmd_add_string(struct json_call *call, const char *pattern)
                        cur_len = end - str;
                }
 
-               dest = blobmsg_realloc_string_buffer(&ctx->buf, cur_len + 1);
+               dest = blobmsg_realloc_string_buffer(buf, cur_len + 1);
                memcpy(dest + len, cur, cur_len);
                len += cur_len;
        }
 
+       dest[len] = 0;
+       blobmsg_add_string_buffer(buf);
+
        if (var)
                return -1;
 
-       dest[len] = 0;
-       blobmsg_add_string_buffer(&ctx->buf);
        return 0;
 }
 
+static int cmd_add_string(struct json_call *call, const char *pattern)
+{
+       return eval_string(call, &call->ctx->buf, NULL, pattern);
+}
+
+int json_script_eval_string(struct json_script_ctx *ctx, struct blob_attr *vars,
+                           struct blob_buf *buf, const char *name,
+                           const char *pattern)
+{
+       struct json_call call = {
+               .ctx = ctx,
+               .vars = vars,
+       };
+
+       return eval_string(&call, buf, name, pattern);
+}
+
 static int cmd_process_strings(struct json_call *call, struct blob_attr *attr)
 {
        struct json_script_ctx *ctx = call->ctx;

diff --git a/json_script.h b/json_script.h
index 6c46f99..25cc04f 100644 (file)
--- a/json_script.h
+++ b/json_script.h
@@ -97,6 +97,16 @@ void json_script_free(struct json_script_ctx *ctx);
 void json_script_run(struct json_script_ctx *ctx, const char *filename,
                     struct blob_attr *vars);
 
+/*
+ * json_script_eval_string - evaluate a string and store the result
+ *
+ * Can be used to process variable references outside of a script
+ * in a same way that they would be interpreted in the script context.
+ */
+int json_script_eval_string(struct json_script_ctx *ctx, struct blob_attr *vars,
+                           struct blob_buf *buf, const char *name,
+                           const char *pattern);
+
 struct json_script_file *
 json_script_file_from_blobmsg(const char *name, void *data, int len);