nwqueue: implement change queue job entry

Implement the Queue Change Job Entry endpoint for both the old NCP 17/6d
and newer NCP 17/7b variants.

Parse the queue job structure, look up the selected job by its job number,
and update the mutable job metadata fields while preserving server-managed
state such as client identity, entry time, job number, queue position, file
name/handle and servicing information.

Allow the job creator to update the standard user-changeable fields and allow
SUPERVISOR or Q_OPERATORS members to update the operator hold flag as well.
Return the documented queue/job/right/servicing completion codes for missing
queues, missing jobs, insufficient rights and jobs already being serviced.

This only updates NetWare queue metadata. It does not change the existing
Q_UNIX_PRINT/lp backend behavior and adds no CUPS dependency.

src/nwqueue.c

@@ -617,11 +617,101 @@ int nw_get_queue_job_file_size(uint32 q_id, int job_id)
   return(result);
 }
 
-int nw_change_queue_job_entry(uint32 q_id, uint8 *qjstruct)
+static int is_queue_operator(NWE_QUEUE *q, uint32 user_id)
 {
-   /*  TODO */
+  int result;
+  if (user_id == 1)       /* SUPERVISOR */
+    return(1);
+  if (!q)
+    return(0);
+  result = nw_is_member_in_set(q->id, "Q_OPERATORS", user_id);
+  return(result == 0);
+}
 
-   return(-0xfb);
+static int change_queue_job_entry_old(INT_QUEUE_JOB *qj, QUEUE_JOB_OLD *job,
+                                      int operator)
+{
+  int old_flags = qj->job_control_flags;
+  int new_flags = (old_flags & 0x20) | (job->job_control_flags & 0x58);
+
+  if (operator)
+    new_flags |= (job->job_control_flags & 0x80);
+  else
+    new_flags |= (old_flags & 0x80);
+
+  qj->target_id         = GET_BE32(job->target_id);
+  qj->execute_time      = get_time_field(job->target_execute_time);
+  qj->job_typ           = GET_BE16(job->job_typ);
+  qj->job_control_flags = new_flags;
+  memcpy(qj->job_description, job->job_description,
+         sizeof(qj->job_description));
+  memcpy(qj->client_area, job->client_area, sizeof(qj->client_area));
+
+  return(old_flags);
+}
+
+static int change_queue_job_entry(INT_QUEUE_JOB *qj, QUEUE_JOB *job,
+                                  int operator)
+{
+  int old_flags = qj->job_control_flags;
+  int request_flags = GET_16(job->job_control_flags);
+  int new_flags = (old_flags & 0x20) | (request_flags & 0x58);
+
+  if (operator)
+    new_flags |= (request_flags & 0x80);
+  else
+    new_flags |= (old_flags & 0x80);
+
+  qj->target_id         = GET_BE32(job->target_id);
+  qj->execute_time      = get_time_field(job->target_execute_time);
+  qj->job_typ           = GET_BE16(job->job_typ);
+  qj->job_control_flags = new_flags;
+  memcpy(qj->job_description, job->job_description,
+         sizeof(qj->job_description));
+  memcpy(qj->client_area, job->client_area, sizeof(qj->client_area));
+
+  return(old_flags);
+}
+
+int nw_change_queue_job_entry(uint32 user_id, uint32 q_id,
+                              uint8 *qjstruct, int old_call)
+{
+  int result=-0xd1; /* no queue */
+  NWE_QUEUE *q=find_queue(q_id);
+
+  if (q) {
+    int job_id = old_call
+               ? GET_BE16(((QUEUE_JOB_OLD*)qjstruct)->job_id)
+               : GET_BE16(((QUEUE_JOB*)qjstruct)->job_id);
+    INT_QUEUE_JOB *qj=find_queue_job(q, job_id);
+
+    result=-0xd5; /* no queue job */
+    if (qj) {
+      int operator = is_queue_operator(q, user_id);
+      int creator  = (user_id == qj->client_id);
+
+      result=-0xd6; /* no job right */
+      if (operator || creator) {
+        int old_flags;
+
+        if (qj->server_station || qj->server_id)
+          return(-0xd7); /* queue servicing */
+
+        old_flags = old_call
+                  ? change_queue_job_entry_old(qj, (QUEUE_JOB_OLD*)qjstruct,
+                                               operator)
+                  : change_queue_job_entry(qj, (QUEUE_JOB*)qjstruct,
+                                           operator);
+        q->changed++;
+        XDPRINTF((2, 0,
+          "Change Queue Job Entry q=0x%x, job=%d, user=0x%x, flags 0x%x->0x%x",
+          q_id, job_id, user_id, old_flags, qj->job_control_flags));
+        result=0;
+      }
+    }
+  }
+
+  return(result);
 }
 
 static int remove_queue_job_file(NWE_QUEUE *q, INT_QUEUE_JOB *qj)