[RFA] gdbserver: Add support for qGetTLSAddr packet

Kevin Buettner kevinb@redhat.com
Mon Dec 6 22:37:00 GMT 2004


The patch below adds qGetTLSAddr packet support to gdbserver.

I wrote this to demonstrate / test the support that I've added on the
GDB side.  I suspect some configury tweaking may be needed to test for
the existence of td_thr_tls_get_addr() in libthread_db.c.  (If it
doesn't exist, then get_thread_local_addr() should be ifdef'd to return
a 0 status.)

If it's otherwise okay, I'm willing to make the necessary configury
changes.  If it's not okay for some other reason, I'd like to address
that first...

Here are pointers to the proposal and related patches:

  http://sources.redhat.com/ml/gdb/2004-11/msg00189.html
  http://sources.redhat.com/ml/gdb-patches/2004-12/msg00168.html
  http://sources.redhat.com/ml/gdb-patches/2004-12/msg00169.html
  http://sources.redhat.com/ml/gdb-patches/2004-12/msg00170.html

Kevin

	* Makefile.in (server.o): Cause USE_THREAD_DB to be defined as
	appropriate.
	* remote-utils.c (decode_qGetTLSAddr_args, encode_qGetTLSAddr_result):
	New functions.
	* server.c (handle_query): Add support for qGetTLSAddr packet.
	* server.h (decode_qGetTLSAddr_args, encode_qGetTLSAddr_result)
	(get_thread_local_addr): Declare.
	* thread-db.c (get_thread_local_addr): New function.

Index: gdbserver/Makefile.in
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/Makefile.in,v
retrieving revision 1.27
diff -u -p -r1.27 Makefile.in
--- gdbserver/Makefile.in	16 Oct 2004 16:18:54 -0000	1.27
+++ gdbserver/Makefile.in	6 Dec 2004 21:58:56 -0000
@@ -246,6 +246,8 @@ proc-service.o: proc-service.c $(server_
 regcache.o: regcache.c $(server_h) $(regdef_h)
 remote-utils.o: remote-utils.c terminal.h $(server_h)
 server.o: server.c $(server_h)
+	$(CC) -c $(CPPFLAGS) $(INTERNAL_CFLAGS) $< @USE_THREAD_DB@
+
 target.o: target.c $(server_h)
 thread-db.o: thread-db.c $(server_h) $(gdb_proc_service_h)
 utils.o: utils.c $(server_h)
Index: gdbserver/remote-utils.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/remote-utils.c,v
retrieving revision 1.22
diff -u -p -r1.22 remote-utils.c
--- gdbserver/remote-utils.c	16 Oct 2004 17:42:00 -0000	1.22
+++ gdbserver/remote-utils.c	6 Dec 2004 21:58:56 -0000
@@ -721,6 +721,60 @@ decode_M_packet (char *from, CORE_ADDR *
   convert_ascii_to_int (&from[i++], to, *len_ptr);
 }
 
+int
+decode_qGetTLSAddr_args (char *buf, unsigned long *thread_id_ptr,
+                         unsigned long *offset_ptr, CORE_ADDR *lm_ptr)
+{
+  int i = 0;
+  char ch;
+
+  *thread_id_ptr = 0;
+  *offset_ptr = 0;
+  *lm_ptr = 0;
+
+  while ((ch = buf[i++]) && ch != ',')
+    {
+      *thread_id_ptr = *thread_id_ptr << 4;
+      *thread_id_ptr |= fromhex (ch) & 0x0f;
+    }
+
+  if (ch == 0)
+    return 0;
+
+  while ((ch = buf[i++]) && ch != ',')
+    {
+      *offset_ptr = *offset_ptr << 4;
+      *offset_ptr |= fromhex (ch) & 0x0f;
+    }
+
+  if (ch == 0)
+    return 0;
+
+  while ((ch = buf[i++]))
+    {
+      *lm_ptr = *lm_ptr << 4;
+      *lm_ptr |= fromhex (ch) & 0x0f;
+    }
+
+  if (ch == 0)
+    return 1;
+  else
+    return 0;
+}
+
+char *
+encode_qGetTLSAddr_result (char *buf, CORE_ADDR addr)
+{
+  int shft = sizeof (CORE_ADDR) * 8 - 4;
+  while (shft >= 0)
+    {
+      *buf++ = tohex ((addr >> shft) & 0x0f);
+      shft -= 4;
+    }
+  *buf = 0;
+  return buf;
+}
+
 /* Ask GDB for the address of NAME, and return it in ADDRP if found.
    Returns 1 if the symbol is found, 0 if it is not, -1 on error.  */
 
Index: gdbserver/server.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/server.c,v
retrieving revision 1.22
diff -u -p -r1.22 server.c
--- gdbserver/server.c	5 Mar 2004 03:44:27 -0000	1.22
+++ gdbserver/server.c	6 Dec 2004 21:58:56 -0000
@@ -142,6 +142,37 @@ handle_query (char *own_buf)
       return;
     }
 
+#ifdef USE_THREAD_DB
+  if (strncmp ("qGetTLSAddr:", own_buf, 12) == 0)
+    {
+      unsigned long thread_id, offset;
+      CORE_ADDR link_map_addr, tls_addr;
+      int status;
+
+      status = decode_qGetTLSAddr_args (own_buf + 12, &thread_id, &offset,
+                                        &link_map_addr);
+      if (!status)
+	{
+	  /* Malformed qGetTLSAddr packet.  */
+	  write_enn (own_buf);
+	  return;
+	}
+
+      status = get_thread_local_addr (thread_id, offset, link_map_addr,
+                                      &tls_addr);
+
+      if (!status)
+	{
+	  /* Unable to obtain thread local address.  */
+	  write_enn (own_buf);
+	  return;
+	}
+
+      encode_qGetTLSAddr_result (own_buf, tls_addr);
+      return;
+    }
+#endif
+
   /* Otherwise we didn't know what packet it was.  Say we didn't
      understand it.  */
   own_buf[0] = 0;
Index: gdbserver/server.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/server.h,v
retrieving revision 1.15
diff -u -p -r1.15 server.h
--- gdbserver/server.h	12 Mar 2004 20:51:21 -0000	1.15
+++ gdbserver/server.h	6 Dec 2004 21:58:56 -0000
@@ -147,6 +147,10 @@ void decode_m_packet (char *from, CORE_A
 void decode_M_packet (char *from, CORE_ADDR * mem_addr_ptr,
 		      unsigned int *len_ptr, char *to);
 
+int decode_qGetTLSAddr_args (char *buf, unsigned long *thread_id_ptr,
+                             unsigned long *offset_ptr, CORE_ADDR *lm_ptr);
+char * encode_qGetTLSAddr_result (char *buf, CORE_ADDR addr);
+
 int unhexify (char *bin, const char *hex, int count);
 int hexify (char *hex, const char *bin, int count);
 
@@ -178,4 +182,8 @@ void init_registers (void);
 		 ? (registers_length () + 32) \
 		 : 2000)
 
+/* Functions from thread-db.c.  */
+
+int get_thread_local_addr (unsigned long thread_id, unsigned long offset,
+                           CORE_ADDR link_map_addr, CORE_ADDR *tls_addr_ptr);
 #endif /* SERVER_H */
Index: gdbserver/thread-db.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/thread-db.c,v
retrieving revision 1.2
diff -u -p -r1.2 thread-db.c
--- gdbserver/thread-db.c	16 Oct 2004 17:42:00 -0000	1.2
+++ gdbserver/thread-db.c	6 Dec 2004 21:58:56 -0000
@@ -366,3 +366,27 @@ thread_db_init ()
 
   return 0;
 }
+
+int
+get_thread_local_addr (unsigned long thread_id, unsigned long offset,
+                       CORE_ADDR link_map_addr, CORE_ADDR *tls_addr_ptr)
+{
+  td_thrhandle_t thread_handle;
+  td_err_e status;
+  void *addr;
+
+  status = td_ta_map_id2thr (thread_agent, (thread_t) thread_id,
+                             &thread_handle);
+
+  if (status != TD_OK)
+    return 0;
+
+  status = td_thr_tls_get_addr (&thread_handle, (void *) (long) link_map_addr,
+                                (size_t) offset, &addr);
+  *tls_addr_ptr = (CORE_ADDR) (long) addr;
+
+  if (status != TD_OK)
+    return 0;
+  else
+    return 1;
+}



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