remote protocol support for TARGET_OBJECT_AUXV

[Roland McGrath <roland at redhat dot com>]

I am proposing a new query packet `qAuxVector' to support reading
TARGET_OBJECT_AUXV data.  Here's the proposed docs addition describing it.
After that, I've appended (short) patches implementing it in gdb and
gdbserver so you can see concretely what I mean.


Thanks,
Roland


Index: gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.192
diff -u -b -p -r1.192 gdb.texinfo
--- gdb.texinfo	4 Feb 2004 23:24:43 -0000	1.192
+++ gdb.texinfo	4 Feb 2004 23:56:55 -0000
@@ -20420,6 +20420,23 @@ The target does not need to look up any 
 The target requests the value of a new symbol @var{sym_name} (hex
 encoded).  @value{GDBN} will continue to supply the values of symbols
 (if available), until the target ceases to request them.
+@end table
+
+@item @code{qAuxVector}:@var{offset},@var{length} --- auxiliary vector data
+
+Read from the target's @dfn{auxiliary vector}, treated as an
+uninterpreted block of bytes.  (@xref{Auxiliary Vector}.)
+Request @var{length} bytes starting at @var{offset} bytes into the data.
+
+Reply:
+@table @samp
+@item @code{=}@var{data}
+@var{data} (hex encoded) contains the data bytes read.
+There is no more auxiliary data after what was requested.
+
+@item @code{+}@var{data}
+@var{data} (hex encoded) contains the data bytes read.
+There may be additional data that can be read with another request.
 @end table
 
 @end table



2004-02-01  Roland McGrath  <roland@redhat.com>

	* remote.c (remote_protocol_qAuxVector): New variable.
	(init_all_packet_configs): Initialize it.
	(set_remote_protocol_qAuxVector_packet_cmd): New function.
	(show_remote_protocol_qAuxVector_packet_cmd): New function.
	(show_remote_cmd): Call it.
	(_initialize_remote): Initialize commands.
	(remote_xfer_partial): If enabled, use qAuxVector query to service
	TARGET_OBJECT_AUXV requests.

Index: remote.c
===================================================================
RCS file: /cvs/src/src/gdb/remote.c,v
retrieving revision 1.128
diff -u -b -p -r1.128 remote.c
--- remote.c	26 Jan 2004 23:07:00 -0000	1.128
+++ remote.c	4 Feb 2004 23:56:37 -0000
@@ -981,6 +981,23 @@ show_remote_protocol_binary_download_cmd
   show_packet_config_cmd (&remote_protocol_binary_download);
 }
 
+/* Should we try the 'qAuxVector' (target auxiliary vector read) request? */
+static struct packet_config remote_protocol_qAuxVector;
+
+static void
+set_remote_protocol_qAuxVector_packet_cmd (char *args, int from_tty,
+					   struct cmd_list_element *c)
+{
+  update_packet_config (&remote_protocol_qAuxVector);
+}
+
+static void
+show_remote_protocol_qAuxVector_packet_cmd (char *args, int from_tty,
+					    struct cmd_list_element *c)
+{
+  show_packet_config_cmd (&remote_protocol_qAuxVector);
+}
+
 
 /* Tokens for use by the asynchronous signal handlers for SIGINT */
 static void *sigint_remote_twice_token;
@@ -2070,6 +2087,7 @@ init_all_packet_configs (void)
   /* Force remote_write_bytes to check whether target supports binary
      downloading. */
   update_packet_config (&remote_protocol_binary_download);
+  update_packet_config (&remote_protocol_qAuxVector);
 }
 
 /* Symbol look-up. */
@@ -4872,6 +4890,50 @@ remote_xfer_partial (struct target_ops *
     case TARGET_OBJECT_AVR:
       query_type = 'R';
       break;
+
+    case TARGET_OBJECT_AUXV:
+      if (remote_protocol_qAuxVector.support != PACKET_DISABLE)
+	{
+	  unsigned int total = 0;
+	  while (len > 0)
+	    {
+	      LONGEST n = min ((rs->remote_packet_size - 2) / 2, len);
+	      snprintf (buf2, rs->remote_packet_size,
+			"qAuxVector:%s,%s",
+			phex_nz (offset, sizeof offset),
+			phex_nz (n, sizeof n));
+	      i = putpkt (buf2);
+	      if (i < 0)
+		return total > 0 ? total : i;
+	      buf2[0] = '\0';
+	      getpkt (buf2, rs->remote_packet_size, 0);
+	      if (packet_ok (buf2, &remote_protocol_qAuxVector) != PACKET_OK)
+		return total > 0 ? total : -1;
+	      switch (buf2[0])
+		{
+		case '=':	/* Final data.  */
+		  return total + hex2bin (&buf2[1], readbuf, len);
+
+		case '+':	/* Some data here, but there is more.  */
+		  i = hex2bin (&buf2[2], readbuf, len);
+		  if (i > 0)
+		    {
+		      readbuf = (void *) ((char *) readbuf + i);
+		      offset += i;
+		      len -= i;
+		      total += i;
+		      break;
+		    }
+
+		default:
+		  warning ("Malformed response to qAuxVector: %s", buf2);
+		  return total > 0 ? total : i;
+		}
+	    }
+	  return total;
+	}
+      return -1;
+
     default:
       return -1;
     }
@@ -5369,6 +5431,7 @@ show_remote_cmd (char *args, int from_tt
   show_remote_protocol_qSymbol_packet_cmd (args, from_tty, NULL);
   show_remote_protocol_vcont_packet_cmd (args, from_tty, NULL);
   show_remote_protocol_binary_download_cmd (args, from_tty, NULL);
+  show_remote_protocol_qAuxVector_packet_cmd (args, from_tty, NULL);
 }
 
 static void
@@ -5610,6 +5673,13 @@ in a memory packet.\n",
 			 "Z4", "access-watchpoint",
 			 set_remote_protocol_Z_access_wp_packet_cmd,
 			 show_remote_protocol_Z_access_wp_packet_cmd,
+			 &remote_set_cmdlist, &remote_show_cmdlist,
+			 0);
+
+  add_packet_config_cmd (&remote_protocol_qAuxVector,
+			 "qAuxVector", "read-aux-vector",
+			 set_remote_protocol_qAuxVector_packet_cmd,
+			 show_remote_protocol_qAuxVector_packet_cmd,
 			 &remote_set_cmdlist, &remote_show_cmdlist,
 			 0);
 


2004-02-01  Roland McGrath  <roland@redhat.com>

	* target.h (struct target_ops): New member `read_auxv'.
	* server.c (handle_query): Handle qAuxVector query using that hook.
	* linux-low.c (linux_read_auxv): New function.
	(linux_target_ops): Initialize `read_auxv' member to that.

Index: gdbserver/linux-low.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/linux-low.c,v
retrieving revision 1.27
diff -b -p -u -r1.27 linux-low.c
--- gdbserver/linux-low.c	31 Jan 2004 22:19:31 -0000	1.27
+++ gdbserver/linux-low.c	4 Feb 2004 23:55:48 -0000
@@ -1381,6 +1381,32 @@ linux_send_signal (int signum)
     kill (signal_pid, signum);
 }
 
+/* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET
+   to debugger memory starting at MYADDR.  */
+
+static int
+linux_read_auxv (CORE_ADDR offset, char *myaddr, unsigned int len)
+{
+  char filename[PATH_MAX];
+  int fd, n;
+
+  snprintf (filename, sizeof filename, "/proc/%d/auxv", inferior_pid);
+
+  fd = open (filename, O_RDONLY);
+  if (fd < 0)
+    return -1;
+
+  if (offset != (CORE_ADDR) 0
+      && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset)
+    n = -1;
+  else
+    n = read (fd, myaddr, len);
+
+  close (fd);
+
+  return n;
+}
+
 
 static struct target_ops linux_target_ops = {
   linux_create_inferior,
@@ -1396,6 +1422,7 @@ static struct target_ops linux_target_op
   linux_write_memory,
   linux_look_up_symbols,
   linux_send_signal,
+  linux_read_auxv,
 };
 
 static void
Index: gdbserver/server.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/server.c,v
retrieving revision 1.16
diff -b -p -u -r1.16 server.c
--- gdbserver/server.c	13 Oct 2003 16:17:21 -0000	1.16
+++ gdbserver/server.c	4 Feb 2004 23:55:48 -0000
@@ -120,6 +120,31 @@ handle_query (char *own_buf)
 	}
     }
       
+  if (strncmp ("qAuxVector:", own_buf, 11) == 0)
+    {
+      if (the_target->read_auxv == NULL)
+	strcpy (own_buf, "E00");
+      else
+	{
+	  char data[(PBUFSIZ - 2) / 2];
+	  CORE_ADDR ofs;
+	  unsigned int len;
+	  int n;
+	  decode_m_packet (&own_buf[11], &ofs, &len); /* "OFS,LEN" */
+	  if (len > sizeof data)
+	    len = sizeof data;
+	  n = (*the_target->read_auxv) (ofs, data, len);
+	  if (n < 0)
+	    strcpy (own_buf, "E00");
+	  else
+	    {
+	      own_buf[0] = n < len ? '=' : '+';
+	      convert_int_to_ascii (data, &own_buf[1], n);
+	    }
+	}
+      return;
+    }
+
   /* Otherwise we didn't know what packet it was.  Say we didn't
      understand it.  */
   own_buf[0] = 0;
Index: gdbserver/target.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbserver/target.h,v
retrieving revision 1.8
diff -b -p -u -r1.8 target.h
--- gdbserver/target.h	13 Oct 2003 16:17:21 -0000	1.8
+++ gdbserver/target.h	4 Feb 2004 23:55:48 -0000
@@ -125,6 +125,12 @@ struct target_ops
 
   /* Send a signal to the inferior process, however is appropriate.  */
   void (*send_signal) (int);
+
+  /* Read auxiliary vector data from the inferior process.
+
+     Read LEN bytes at OFFSET into a buffer at MYADDR.  */
+
+  int (*read_auxv) (CORE_ADDR offset, char *myaddr, unsigned int len);
 };
 
 extern struct target_ops *the_target;