gdbserver: Fix qSupported:xmlRegisters=i386;UnknownFeature+ handling
authorPedro Alves <palves@redhat.com>
Thu, 19 Nov 2015 18:31:50 +0000 (18:31 +0000)
committerPedro Alves <palves@redhat.com>
Thu, 19 Nov 2015 18:32:55 +0000 (18:32 +0000)
The target_process_qsupported method is called for each qSupported
feature that the common code does not recognize.  The only current
implementation, for x86 Linux (x86_linux_process_qsupported), assumes
that it either is called with the "xmlRegisters=i386" feature, or that
it is isn't called at all, indicating the connected GDB predates x86
XML descriptions.

That's a bad assumption however.  If GDB sends in a new/unknown (to
core gdbserver) feature after "xmlRegisters=i386", say, something like
qSupported:xmlRegisters=i386;UnknownFeature+, then when
target_process_qsupported is called for "UnknownFeature+",
x86_linux_process_qsupported clears the 'use_xml' global and calls
x86_linux_update_xmltarget, and gdbserver ends up _not_ reporting a
XML description...

This commit changes the target_process_qsupported API to instead pass
down a vector of unprocessed qSupported features in one go.

(There's an early call to target_process_qsupported(NULL) that
indicates "starting qSupported processing".  There's no matching call
to mark the end of processing, though.  I first fixed this by passing
(char *)-1 to indicate that, and adjusted the x86 backend to only
clear 'use_xml' when qSupported processing starts, and then only call
x86_linux_update_xmltarget() when (char *)-1 was passed.  However, I
wasn't that happy with the hack and came up this alternative version.)

gdb/gdbserver/ChangeLog:
2015-11-19  Pedro Alves  <palves@redhat.com>

* linux-low.c (linux_process_qsupported): Change prototype.
Adjust.
* linux-low.h (struct linux_target_ops) <process_qsupported>:
Change prototype.
* linux-x86-low.c (x86_linux_process_qsupported): Change prototype
and adjust to loop over all features.
* server.c (handle_query) <qSupported>: Adjust to call
target_process_qsupported once, passing it a vector of unprocessed
features.
* target.h (struct target_ops) <process_qsupported>: Change
prototype.
(target_process_qsupported): Adjust.

gdb/gdbserver/ChangeLog
gdb/gdbserver/linux-low.c
gdb/gdbserver/linux-low.h
gdb/gdbserver/linux-x86-low.c
gdb/gdbserver/server.c
gdb/gdbserver/target.h

index c515249..0d2963a 100644 (file)
@@ -1,5 +1,20 @@
 2015-11-19  Pedro Alves  <palves@redhat.com>
 
+       * linux-low.c (linux_process_qsupported): Change prototype.
+       Adjust.
+       * linux-low.h (struct linux_target_ops) <process_qsupported>:
+       Change prototype.
+       * linux-x86-low.c (x86_linux_process_qsupported): Change prototype
+       and adjust to loop over all features.
+       * server.c (handle_query) <qSupported>: Adjust to call
+       target_process_qsupported once, passing it a vector of unprocessed
+       features.
+       * target.h (struct target_ops) <process_qsupported>: Change
+       prototype.
+       (target_process_qsupported): Adjust.
+
+2015-11-19  Pedro Alves  <palves@redhat.com>
+
        * configure.ac (ERROR_ON_WARNING): Don't check whether in C++
        mode.
        * configure: Regenerate.
index 41ab510..e3a56a7 100644 (file)
@@ -6128,10 +6128,10 @@ linux_read_loadmap (const char *annex, CORE_ADDR offset,
 #endif /* defined PT_GETDSBT || defined PTRACE_GETFDPIC */
 
 static void
-linux_process_qsupported (const char *query)
+linux_process_qsupported (char **features, int count)
 {
   if (the_low_target.process_qsupported != NULL)
-    the_low_target.process_qsupported (query);
+    the_low_target.process_qsupported (features, count);
 }
 
 static int
index ccf4c94..f1d4f0f 100644 (file)
@@ -199,7 +199,7 @@ struct linux_target_ops
   void (*prepare_to_resume) (struct lwp_info *);
 
   /* Hook to support target specific qSupported.  */
-  void (*process_qsupported) (const char *);
+  void (*process_qsupported) (char **, int count);
 
   /* Returns true if the low target supports tracepoints.  */
   int (*supports_tracepoints) (void);
index 89ec4e5..7f07194 100644 (file)
@@ -1356,29 +1356,35 @@ x86_linux_update_xmltarget (void)
    PTRACE_GETREGSET.  */
 
 static void
-x86_linux_process_qsupported (const char *query)
+x86_linux_process_qsupported (char **features, int count)
 {
+  int i;
+
   /* Return if gdb doesn't support XML.  If gdb sends "xmlRegisters="
      with "i386" in qSupported query, it supports x86 XML target
      descriptions.  */
   use_xml = 0;
-  if (query != NULL && startswith (query, "xmlRegisters="))
+  for (i = 0; i < count; i++)
     {
-      char *copy = xstrdup (query + 13);
-      char *p;
+      const char *feature = features[i];
 
-      for (p = strtok (copy, ","); p != NULL; p = strtok (NULL, ","))
+      if (startswith (feature, "xmlRegisters="))
        {
-         if (strcmp (p, "i386") == 0)
+         char *copy = xstrdup (feature + 13);
+         char *p;
+
+         for (p = strtok (copy, ","); p != NULL; p = strtok (NULL, ","))
            {
-             use_xml = 1;
-             break;
+             if (strcmp (p, "i386") == 0)
+               {
+                 use_xml = 1;
+                 break;
+               }
            }
-       } 
 
-      free (copy);
+         free (copy);
+       }
     }
-
   x86_linux_update_xmltarget ();
 }
 
index fd2804b..7d6c9cc 100644 (file)
@@ -2054,9 +2054,6 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
       char *p = &own_buf[10];
       int gdb_supports_qRelocInsn = 0;
 
-      /* Start processing qSupported packet.  */
-      target_process_qsupported (NULL);
-
       /* Process each feature being provided by GDB.  The first
         feature will follow a ':', and latter features will follow
         ';'.  */
@@ -2064,6 +2061,7 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
        {
          char **qsupported = NULL;
          int count = 0;
+         int unknown = 0;
          int i;
 
          /* Two passes, to avoid nested strtok calls in
@@ -2128,11 +2126,20 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
              else if (strcmp (p, "vContSupported+") == 0)
                vCont_supported = 1;
              else
-               target_process_qsupported (p);
-
-             free (p);
+               {
+                 /* Move the unknown features all together.  */
+                 qsupported[i] = NULL;
+                 qsupported[unknown] = p;
+                 unknown++;
+               }
            }
 
+         /* Give the target backend a chance to process the unknown
+            features.  */
+         target_process_qsupported (qsupported, unknown);
+
+         for (i = 0; i < count; i++)
+           free (qsupported[i]);
          free (qsupported);
        }
 
index 769c876..6fa454d 100644 (file)
@@ -306,8 +306,9 @@ struct target_ops
   int (*read_loadmap) (const char *annex, CORE_ADDR offset,
                       unsigned char *myaddr, unsigned int len);
 
-  /* Target specific qSupported support.  */
-  void (*process_qsupported) (const char *);
+  /* Target specific qSupported support.  FEATURES is an array of
+     features with COUNT elements.  */
+  void (*process_qsupported) (char **features, int count);
 
   /* Return 1 if the target supports tracepoints, 0 (or leave the
      callback NULL) otherwise.  */
@@ -519,11 +520,11 @@ int kill_inferior (int);
   (the_target->supports_multi_process ? \
    (*the_target->supports_multi_process) () : 0)
 
-#define target_process_qsupported(query)               \
+#define target_process_qsupported(features, count)     \
   do                                                   \
     {                                                  \
       if (the_target->process_qsupported)              \
-       the_target->process_qsupported (query);         \
+       the_target->process_qsupported (features, count); \
     } while (0)
 
 #define target_supports_tracepoints()                  \