[PATCH] gdbserver: Handle 'v' packet while processing qSymbol.

[Marcin KoÅcielnicki <koriakin at 0x04 dot net>]

On powerpc64, qSymbol query may require gdb to read a function
descriptor, sending a vFile packet to gdbserver.  Thus, we need
to handle 'v' packet in look_up_one_symbol.

vFile replies may be quite long, and require reallocating own_buf.
Since handle_v_requests assumes the buffer is the static global own_buf
from server.c and reallocates it, we need to make own_buf global and
use it from look_up_one_symbol instead of using our own auto variable.
I've also done the same change in relocate_instruction, just in case.

On gdb side, in remote_check_symbols, rs->buf may be clobbered by vFile
handling, yet we need its contents for the reply (the symbol name is
stored there).  Allocate a new buffer instead.

This broke fast tracepoints on powerpc64, due to errors in reading IPA
symbols.

gdb/ChangeLog:

	* remote.c (xfreep): New function.
	(remote_check_symbols): Allocate own buffer for reply.

gdbserver/ChangeLog:

	* remote-utils.c (look_up_one_symbol): Remove own_buf, handle 'v'
	packets.
	(relocate_instruction): Remove own_buf.
	* server.c (own_buf): Make global.
	(handle_v_requests): Make global.
	* server.h (own_buf): New declaration.
	(handle_v_requests): New prototype.
---

 gdb/ChangeLog                |  5 +++++
 gdb/gdbserver/ChangeLog      | 10 ++++++++++
 gdb/gdbserver/remote-utils.c | 41 +++++++++++++++++++++++++++--------------
 gdb/gdbserver/server.c       |  4 ++--
 gdb/gdbserver/server.h       |  4 ++++
 gdb/remote.c                 | 22 +++++++++++++++++-----
 6 files changed, 65 insertions(+), 21 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index febe960..41f826e 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2016-03-12  Marcin KoÅcielnicki  <koriakin@0x04.net>
+
+	* remote.c (xfreep): New function.
+	(remote_check_symbols): Allocate own buffer for reply.
+
 2016-03-11  Marcin KoÅcielnicki  <koriakin@0x04.net>
 
 	* s390-linux-tdep.c (s390_ax_pseudo_register_collect): New function.
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index dda87b0..7ce2690 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,13 @@
+2016-03-12  Marcin KoÅcielnicki  <koriakin@0x04.net>
+
+	* remote-utils.c (look_up_one_symbol): Remove own_buf, handle 'v'
+	packets.
+	(relocate_instruction): Remove own_buf.
+	* server.c (own_buf): Make global.
+	(handle_v_requests): Make global.
+	* server.h (own_buf): New declaration.
+	(handle_v_requests): New prototype.
+
 2016-03-09  Marcin KoÅcielnicki  <koriakin@0x04.net>
 
 	* linux-ppc-low.c (ppc_supports_tracepoints): New function.
diff --git a/gdb/gdbserver/remote-utils.c b/gdb/gdbserver/remote-utils.c
index e751473..24f92c2 100644
--- a/gdb/gdbserver/remote-utils.c
+++ b/gdb/gdbserver/remote-utils.c
@@ -1462,7 +1462,7 @@ clear_symbol_cache (struct sym_cache **symcache_p)
 int
 look_up_one_symbol (const char *name, CORE_ADDR *addrp, int may_ask_gdb)
 {
-  char own_buf[266], *p, *q;
+  char *p, *q;
   int len;
   struct sym_cache *sym;
   struct process_info *proc;
@@ -1499,21 +1499,35 @@ look_up_one_symbol (const char *name, CORE_ADDR *addrp, int may_ask_gdb)
      main loop.  For now, this is an adequate approximation; allow
      GDB to read from memory while it figures out the address of the
      symbol.  */
-  while (own_buf[0] == 'm')
+  while (1)
     {
-      CORE_ADDR mem_addr;
-      unsigned char *mem_buf;
-      unsigned int mem_len;
+      if (own_buf[0] == 'm')
+	{
+	  CORE_ADDR mem_addr;
+	  unsigned char *mem_buf;
+	  unsigned int mem_len;
 
-      decode_m_packet (&own_buf[1], &mem_addr, &mem_len);
-      mem_buf = (unsigned char *) xmalloc (mem_len);
-      if (read_inferior_memory (mem_addr, mem_buf, mem_len) == 0)
-	bin2hex (mem_buf, own_buf, mem_len);
+	  decode_m_packet (&own_buf[1], &mem_addr, &mem_len);
+	  mem_buf = (unsigned char *) xmalloc (mem_len);
+	  if (read_inferior_memory (mem_addr, mem_buf, mem_len) == 0)
+	    bin2hex (mem_buf, own_buf, mem_len);
+	  else
+	    write_enn (own_buf);
+	  free (mem_buf);
+	  if (putpkt (own_buf) < 0)
+	    return -1;
+	}
+      else if (own_buf[0] == 'v')
+	{
+	  int new_len = -1;
+	  handle_v_requests (own_buf, len, &new_len);
+	  if (new_len != -1)
+	    putpkt_binary (own_buf, new_len);
+	  else
+	    putpkt (own_buf);
+	}
       else
-	write_enn (own_buf);
-      free (mem_buf);
-      if (putpkt (own_buf) < 0)
-	return -1;
+	break;
       len = getpkt (own_buf);
       if (len < 0)
 	return -1;
@@ -1561,7 +1575,6 @@ look_up_one_symbol (const char *name, CORE_ADDR *addrp, int may_ask_gdb)
 int
 relocate_instruction (CORE_ADDR *to, CORE_ADDR oldloc)
 {
-  char own_buf[266];
   int len;
   ULONGEST written = 0;
 
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index ef715e7..9c50929 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -119,7 +119,7 @@ int disable_packet_qfThreadInfo;
 static struct target_waitstatus last_status;
 static ptid_t last_ptid;
 
-static char *own_buf;
+char *own_buf;
 static unsigned char *mem_buf;
 
 /* A sub-class of 'struct notif_event' for stop, holding information
@@ -2935,7 +2935,7 @@ handle_v_kill (char *own_buf)
 }
 
 /* Handle all of the extended 'v' packets.  */
-static void
+void
 handle_v_requests (char *own_buf, int packet_len, int *new_packet_len)
 {
   if (!disable_packet_vCont)
diff --git a/gdb/gdbserver/server.h b/gdb/gdbserver/server.h
index 3d78fb3..51b2191 100644
--- a/gdb/gdbserver/server.h
+++ b/gdb/gdbserver/server.h
@@ -82,6 +82,8 @@ extern int disable_packet_Tthread;
 extern int disable_packet_qC;
 extern int disable_packet_qfThreadInfo;
 
+extern char *own_buf;
+
 extern int run_once;
 extern int multi_process;
 extern int report_fork_events;
@@ -113,6 +115,8 @@ typedef int gdb_fildes_t;
 #include "event-loop.h"
 
 /* Functions from server.c.  */
+extern void handle_v_requests (char *own_buf, int packet_len,
+			       int *new_packet_len);
 extern int handle_serial_event (int err, gdb_client_data client_data);
 extern int handle_target_event (int err, gdb_client_data client_data);
 
diff --git a/gdb/remote.c b/gdb/remote.c
index f09a06e..5f3d9fd 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -4321,6 +4321,16 @@ init_all_packet_configs (void)
     }
 }
 
+/* Helper function for cleanup below.  Argument is a pointer to a void *
+   pointing to a buffer that needs to be freed.  */
+
+static void
+xfreep (void *arg)
+{
+  void **pptr = (void **) arg;
+  xfree (*pptr);
+}
+
 /* Symbol look-up.  */
 
 static void
@@ -4329,6 +4339,7 @@ remote_check_symbols (void)
   struct remote_state *rs = get_remote_state ();
   char *msg, *reply, *tmp;
   int end;
+  long reply_size;
   struct cleanup *old_chain;
 
   /* The remote side has no concept of inferiors that aren't running
@@ -4350,13 +4361,15 @@ remote_check_symbols (void)
      because we need both at the same time.  */
   msg = (char *) xmalloc (get_remote_packet_size ());
   old_chain = make_cleanup (xfree, msg);
+  reply = (char *) xmalloc (get_remote_packet_size ());
+  make_cleanup (xfreep, &reply);
+  reply_size = get_remote_packet_size ();
 
   /* Invite target to request symbol lookups.  */
 
   putpkt ("qSymbol::");
-  getpkt (&rs->buf, &rs->buf_size, 0);
-  packet_ok (rs->buf, &remote_protocol_packets[PACKET_qSymbol]);
-  reply = rs->buf;
+  getpkt (&reply, &reply_size, 0);
+  packet_ok (reply, &remote_protocol_packets[PACKET_qSymbol]);
 
   while (startswith (reply, "qSymbol:"))
     {
@@ -4384,8 +4397,7 @@ remote_check_symbols (void)
 	}
   
       putpkt (msg);
-      getpkt (&rs->buf, &rs->buf_size, 0);
-      reply = rs->buf;
+      getpkt (&reply, &reply_size, 0);
     }
 
   do_cleanups (old_chain);
-- 
2.7.2