Re: [RFC] remote.c: Add remote TLS support

[Kevin Buettner <kevinb@redhat.com>]

On Thu, 31 Mar 2005 16:20:17 -0700
Kevin Buettner <kevinb@redhat.com> wrote:

> The patch below adds remote TLS support.  It is a rework of the remote.c
> portion of a patch posted late last year:
> 
>     http://sources.redhat.com/ml/gdb-patches/2004-12/msg00169.html
> 
> In looking this over myself, the only thing that I find objectionable
> is that the new function show_remote_protocol_qGetTLSAddr_packet_cmd()
> calls the deprecated function deprecated_show_value_hack().  However,
> it doesn't make much sense to me to implement the set/show commands
> for the qGetTLSAddr packet differently from the support for the other
> protocol packets in remote.c.  So, as I see it the alternatives are:
> 
>     1) Allow this patch in even though it calls a deprecated function.
> 
>     2) Convert the other functions that currently call
>        deprecated_show_value_hack() to use some other mechanism.  Then,
>        resubmit this patch so that the new show_... function introduced
>        in this patch uses the new machinery.
> 
> Opinions?  If (2) is the preferred route, could someone outline how
> the conversion to not use deprecated_show_value_hack() ought to be done?

I ended up deleting all calls to deprecated_show_value_hack().  As
observed in other discussion, these calls were printing redundant
information.  I wish to thank Daniel Jacobowitz for reviewing these
changes.

With that out of the way, I ended up committing the following changes,
only modified slightly from my earlier posting.  (It no longer
refers to the deprecated function and I removed some unused variables
that were leftovers from an even earlier version of the work.)

	* remote.c (remote_protocol_qGetTLSAddr): New static global variable.
	(set_remote_protocol_qGetTLSAddr_packet_cmd)
	(show_remote_protocol_qGetTLSAddr_packet_cmd)
	(remote_get_thread_local_address): New functions.
	(init_all_packet_configs): Initialize remote_protocol_qGetTLSAddr
	variable.
	(init_remote_ops): Initialize ``to_get_thread_local_address'' in
	target vector.
	(show_remote_cmd): Call show_remote_protocol_qGetTLS_Addr_packet_cmd().
	(_initialize_remote):  Register the following commands:
	"set remote get-thread-local-storage-address-packet" and
	"show remote get-thread-local-address-packet".

Index: remote.c
===================================================================
RCS file: /cvs/src/src/gdb/remote.c,v
retrieving revision 1.181
diff -u -p -r1.181 remote.c
--- remote.c	15 Apr 2005 17:44:53 -0000	1.181
+++ remote.c	15 Apr 2005 19:55:11 -0000
@@ -967,6 +967,24 @@ show_remote_protocol_qPart_auxv_packet_c
   show_packet_config_cmd (&remote_protocol_qPart_auxv);
 }
 
+/* Should we try the 'qGetTLSAddr' (Get Thread Local Storage Address) request? */
+static struct packet_config remote_protocol_qGetTLSAddr;
+
+static void
+set_remote_protocol_qGetTLSAddr_packet_cmd (char *args, int from_tty,
+				  struct cmd_list_element *c)
+{
+  update_packet_config (&remote_protocol_qGetTLSAddr);
+}
+
+static void
+show_remote_protocol_qGetTLSAddr_packet_cmd (struct ui_file *file, int from_tty,
+					     struct cmd_list_element *c,
+					     const char *value)
+{
+  show_packet_config_cmd (&remote_protocol_qGetTLSAddr);
+}
+
 static struct packet_config remote_protocol_p;
 
 static void
@@ -2095,6 +2113,7 @@ init_all_packet_configs (void)
      downloading.  */
   update_packet_config (&remote_protocol_binary_download);
   update_packet_config (&remote_protocol_qPart_auxv);
+  update_packet_config (&remote_protocol_qGetTLSAddr);
 }
 
 /* Symbol look-up.  */
@@ -5314,6 +5333,56 @@ remote_pid_to_str (ptid_t ptid)
   return buf;
 }
 
+/* Get the address of the thread local variable in OBJFILE which is
+   stored at OFFSET within the thread local storage for thread PTID.  */
+
+static CORE_ADDR
+remote_get_thread_local_address (ptid_t ptid, CORE_ADDR lm, CORE_ADDR offset)
+{
+  if (remote_protocol_qGetTLSAddr.support != PACKET_DISABLE)
+    {
+      struct remote_state *rs = get_remote_state ();
+      char *buf = alloca (rs->remote_packet_size);
+      char *p = buf;
+
+      strcpy (p, "qGetTLSAddr:");
+      p += strlen (p);
+      p += hexnumstr (p, PIDGET (ptid));
+      *p++ = ',';
+      p += hexnumstr (p, offset);
+      *p++ = ',';
+      p += hexnumstr (p, lm);
+      *p++ = '\0';
+
+      putpkt (buf);
+      getpkt (buf, rs->remote_packet_size, 0);
+      if (packet_ok (buf, &remote_protocol_qGetTLSAddr) == PACKET_OK)
+	{
+	  ULONGEST result;
+
+	  unpack_varlen_hex (buf, &result);
+	  return result;
+	}
+      else
+	{
+	  struct exception e
+	    = { RETURN_ERROR, TLS_GENERIC_ERROR,
+		"Remote target failed to process qGetTLSAddr request" };
+	  throw_exception (e);
+
+	}
+    }
+  else
+    {
+      struct exception e
+	= { RETURN_ERROR, TLS_GENERIC_ERROR,
+	    "TLS not supported or disabled on this target" };
+      throw_exception (e);
+    }
+  /* Not reached.  */
+  return 0;
+}
+
 static void
 init_remote_ops (void)
 {
@@ -5353,6 +5422,7 @@ Specify the serial device it is connecte
   remote_ops.to_stop = remote_stop;
   remote_ops.to_xfer_partial = remote_xfer_partial;
   remote_ops.to_rcmd = remote_rcmd;
+  remote_ops.to_get_thread_local_address = remote_get_thread_local_address;
   remote_ops.to_stratum = process_stratum;
   remote_ops.to_has_all_memory = 1;
   remote_ops.to_has_memory = 1;
@@ -5528,6 +5598,7 @@ show_remote_cmd (char *args, int from_tt
   show_remote_protocol_vcont_packet_cmd (gdb_stdout, from_tty, NULL, NULL);
   show_remote_protocol_binary_download_cmd (gdb_stdout, from_tty, NULL, NULL);
   show_remote_protocol_qPart_auxv_packet_cmd (gdb_stdout, from_tty, NULL, NULL);
+  show_remote_protocol_qGetTLSAddr_packet_cmd (gdb_stdout, from_tty, NULL, NULL);
 }
 
 static void
@@ -5758,6 +5829,13 @@ Show the maximum size of the address (in
 			 &remote_set_cmdlist, &remote_show_cmdlist,
 			 0);
 
+  add_packet_config_cmd (&remote_protocol_qGetTLSAddr,
+			 "qGetTLSAddr", "get-thread-local-storage-address",
+			 set_remote_protocol_qGetTLSAddr_packet_cmd,
+			 show_remote_protocol_qGetTLSAddr_packet_cmd,
+			 &remote_set_cmdlist, &remote_show_cmdlist,
+			 0);
+
   /* Keep the old ``set remote Z-packet ...'' working.  */
   add_setshow_auto_boolean_cmd ("Z-packet", class_obscure,
 				&remote_Z_packet_detect, _("\