TCF Agent: fixed data caching for server side services

When Symbols and/or some other services are configured to run in TCF server,
MEM_ACCESS_RD_STOP can cause infinite loop of cache misses.
Need to lock run control until cache validation is done.

4 files changed, 51 insertions, 9 deletions

diff --git a/agent/tcf/services/breakpoints.c b/agent/tcf/services/breakpoints.c
index a77f3d2d..4ae399d6 100644
--- a/agent/tcf/services/breakpoints.c
+++ b/agent/tcf/services/breakpoints.c
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2007-2017 Wind River Systems, Inc. and others.
+ * Copyright (c) 2007-2019 Wind River Systems, Inc. and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * and Eclipse Distribution License v1.0 which accompany this distribution.
@@ -1627,19 +1627,21 @@ static void plant_at_address_expression(Context * ctx, ContextAddress ip, Breakp
     int error = 0;
 #if ENABLE_Expressions
     Value v;
-    SymbolProperties props;
 
     memset (&v, 0, sizeof (Value));
 
     if (evaluate_expression(ctx, STACK_NO_FRAME, ip, bp->location, 1, &v) < 0) error = errno;
     if (!error && value_to_address(&v, &addr) < 0) error = errno;
+#if ENABLE_Symbols
     if (!error && v.sym != NULL) {
+        SymbolProperties props;
         /* We want to add the LocalEntryOffset */
         get_symbol_props(v.sym, &props);
         /* If the symbol is not a PPC64 function, offset should be 0, so it is safe to add */
         addr += props.local_entry_offset;
     }
 #endif
+#endif
 #if ENABLE_SkipPrologueWhenPlanting
     /* Even if addr is incremented by local_entry_offset, we still should be on right code area */
     if (!error && bp->skip_prologue && v.sym != NULL && skip_function_prologue(ctx, v.sym, &addr) < 0) error = errno;
@@ -1674,6 +1676,7 @@ static void plant_at_address_expression(Context * ctx, ContextAddress ip, Breakp
             while (v.sym_list[n] != NULL) {
                 Symbol * sym = v.sym_list[n++];
                 if (get_symbol_address(sym, &addr) == 0) {
+                    SymbolProperties props;
                     /* We want to add the LocalEntryOffset */
                     get_symbol_props(sym, &props);
                     /* If the symbol is not a PPC64 function, offset should be 0, so it is safe to add */
diff --git a/agent/tcf/services/disassembly.c b/agent/tcf/services/disassembly.c
index c6c35653..07f018c8 100644
--- a/agent/tcf/services/disassembly.c
+++ b/agent/tcf/services/disassembly.c
@@ -278,7 +278,7 @@ static int disassemble_block(Context * ctx, OutputStream * out, uint8_t * mem_bu
     return 0;
 }
 
-#if SERVICE_LineNumbers
+#if ENABLE_LineNumbers
 static void address_to_line_cb(CodeArea * area, void * args) {
     CodeArea ** p = (CodeArea **)args;
     if (*p == NULL || (*p)->start_address < area->start_address) {
@@ -325,7 +325,7 @@ static void disassemble_cache_client(void * x) {
         ContextAddress sym_size = 0;
         int sym_addr_ok = 0;
         int sym_size_ok = 0;
-#if SERVICE_Symbols
+#if ENABLE_Symbols
         {
             Symbol * sym = NULL;
             if (find_symbol_by_addr(ctx, STACK_NO_FRAME, args->addr, &sym) == 0) {
@@ -338,7 +338,7 @@ static void disassemble_cache_client(void * x) {
             }
         }
 #endif
-#if SERVICE_LineNumbers
+#if ENABLE_LineNumbers
         if (!sym_addr_ok || !sym_size_ok) {
             CodeArea * area = NULL;
             address_to_line(ctx, args->addr, args->addr + 1, address_to_line_cb, &area);
@@ -476,7 +476,7 @@ static void read_disassembly_params(InputStream * inp, const char * name, void *
         args->pseudo_instr = json_read_boolean(inp);
     }
     else if (strcmp(name, "OpcodeValue") == 0) {
-        args->opcode_value =json_read_boolean(inp);
+        args->opcode_value = json_read_boolean(inp);
     }
     else {
         json_skip_object(inp);
diff --git a/agent/tcf/services/expressions.c b/agent/tcf/services/expressions.c
index e9434607..81de0026 100644
--- a/agent/tcf/services/expressions.c
+++ b/agent/tcf/services/expressions.c
@@ -1574,6 +1574,7 @@ static void load_value(Value * v) {
     else if (v->value != NULL) {
         /* OK */
     }
+#if ENABLE_Symbols
     else if (v->loc != NULL) {
         size_t size = 0;
         void * value = NULL;
@@ -1584,6 +1585,7 @@ static void load_value(Value * v) {
         v->size = (ContextAddress)size;
         sign_extend(v, loc);
     }
+#endif
     else {
         error(ERR_OTHER, "Has no value");
     }
@@ -2041,7 +2043,9 @@ static void primary_expression(int mode, Value * v) {
         next_sy();
     }
     else if (text_sy == SY_VAL) {
+#if ENABLE_Symbols
         int flags = text_val_flags;
+#endif
         *v = text_val;
         next_sy();
 #if ENABLE_Symbols
diff --git a/agent/tcf/services/runctrl.c b/agent/tcf/services/runctrl.c
index 653381c0..695cf9fb 100644
--- a/agent/tcf/services/runctrl.c
+++ b/agent/tcf/services/runctrl.c
@@ -70,6 +70,7 @@ static unsigned listener_cnt = 0;
 static unsigned listener_max = 0;
 
 static const char RUN_CONTROL[] = "RunControl";
+static const char CONTEXT_PROXY[] = "ContextProxy";
 
 typedef struct ContextExtensionRC {
     int pending_safe_event; /* safe events are waiting for this context to be stopped */
@@ -111,10 +112,16 @@ typedef struct ContextExtensionRC {
 } ContextExtensionRC;
 
 static size_t context_extension_offset = 0;
-
 #define EXT(ctx) (ctx ? ((ContextExtensionRC *)((char *)(ctx) + context_extension_offset)) : NULL)
 #define link2ctx(lnk) ((Context *)((char *)(lnk) - offsetof(ContextExtensionRC, link) - context_extension_offset))
 
+typedef struct ChannelExtensionRC {
+    int cache_lock;
+} ChannelExtensionRC;
+
+static size_t channel_extension_offset = 0;
+#define EXT_CH(ch) ((ChannelExtensionRC *)((char *)(ch) + channel_extension_offset))
+
 typedef struct SafeEvent {
     Context * ctx;
     EventCallBack * done;
@@ -2759,8 +2766,8 @@ static void clear_context_proxy_cache(Context * ctx) {
             int i;
             for (i = 0; i < c->peer_service_cnt; i++) {
                 char * nm = c->peer_service_list[i];
-                if (strcmp(nm, "ContextProxy") == 0) {
-                    protocol_send_command(c, "ContextProxy", "clear", context_proxy_reply, NULL);
+                if (strcmp(nm, CONTEXT_PROXY) == 0) {
+                    protocol_send_command(c, CONTEXT_PROXY, "clear", context_proxy_reply, NULL);
                     json_write_string(&c->out, ctx->id);
                     write_stream(&c->out, 0);
                     write_stream(&c->out, MARKER_EOM);
@@ -2819,12 +2826,38 @@ static void event_context_exited(Context * ctx, void * args) {
 }
 
 static void channel_closed(Channel * c) {
+    ChannelExtensionRC * ext_ch = EXT_CH(c);
     LINK * l;
     for (l = context_root.next; l != &context_root; l = l ->next) {
         Context * ctx = ctxl2ctxp(l);
         ContextExtensionRC * ext = EXT(ctx);
         if (ext->step_channel == c) cancel_step_mode(ctx);
     }
+    if (ext_ch->cache_lock) {
+        ext_ch->cache_lock = 0;
+        run_ctrl_unlock();
+    }
+}
+
+static void context_cache_lock(Channel * c) {
+    ChannelExtensionRC * ext = EXT_CH(c);
+    json_test_char(&c->inp, MARKER_EOM);
+    assert(ext->cache_lock == 0);
+    ext->cache_lock = 1;
+    run_ctrl_lock();
+}
+
+static void context_cache_unlock(Channel * c) {
+    ChannelExtensionRC * ext = EXT_CH(c);
+    json_test_char(&c->inp, MARKER_EOM);
+    assert(ext->cache_lock == 1);
+    ext->cache_lock = 0;
+    run_ctrl_unlock();
+}
+
+static void channel_opened(Channel * c) {
+    add_event_handler(c, CONTEXT_PROXY, "lock", context_cache_lock);
+    add_event_handler(c, CONTEXT_PROXY, "unlock", context_cache_unlock);
 }
 
 static void event_context_disposed(Context * ctx, void * args) {
@@ -2870,7 +2903,9 @@ void ini_run_ctrl_service(Protocol * proto, TCFBroadcastGroup * bcg) {
     broadcast_group = bcg;
     add_context_event_listener(&listener, NULL);
     add_channel_close_listener(channel_closed);
+    add_channel_open_listener(channel_opened);
     context_extension_offset = context_extension(sizeof(ContextExtensionRC));
+    channel_extension_offset = channel_extension(sizeof(ChannelExtensionRC));
     add_command_handler(proto, RUN_CONTROL, "getContext", command_get_context);
     add_command_handler(proto, RUN_CONTROL, "getChildren", command_get_children);
     add_command_handler(proto, RUN_CONTROL, "getState", command_get_state);