Add RM_SetContextUser to support acl validation in RM_Call (and scripts) (#10966)

Adds a number of user management/ACL validaiton/command execution functions to improve a
Redis module's ability to enforce ACLs correctly and easily.

* RM_SetContextUser - sets a RedisModuleUser on the context, which RM_Call will use to both
  validate ACLs (if requested and set) as well as assign to the client so that scripts executed via
  RM_Call will have proper ACL validation.
* RM_SetModuleUserACLString - Enables one to pass an entire ACL string, not just a single OP
  and have it applied to the user
* RM_GetModuleUserACLString - returns a stringified version of the user's ACL (same format as dump
  and list).  Contains an optimization to cache the stringified version until the underlying ACL is modified.
* Slightly re-purpose the "C" flag to RM_Call from just being about ACL check before calling the
  command, to actually running the command with the right user, so that it also affects commands
  inside EVAL scripts. see #11231

1 files changed, 7 insertions, 0 deletions

diff --git a/src/networking.c b/src/networking.c
index 932413816..3cdbe16ce 100644
--- a/src/networking.c
+++ b/src/networking.c
@@ -601,6 +601,13 @@ void addReplyErrorSds(client *c, sds err) {
     addReplyErrorSdsEx(c, err, 0);
 }
 
+/* See addReplyErrorLength for expectations from the input string. */
+/* As a side effect the SDS string is freed. */
+void addReplyErrorSdsSafe(client *c, sds err) {
+    err = sdsmapchars(err, "\r\n", "  ",  2);
+    addReplyErrorSdsEx(c, err, 0);
+}
+
 /* Internal function used by addReplyErrorFormat and addReplyErrorFormatEx.
  * Refer to afterErrorReply for more information about the flags. */
 static void addReplyErrorFormatInternal(client *c, int flags, const char *fmt, va_list ap) {