Use LWP IDs with ptrace register requests on FreeBSD.

This allows gdb to fetch per-thread registers for multi-threaded FreeBSD
processes.

Export get_ptrace_pid() from inf-ptrace.c and use it to determine the PID
to pass to ptrace in pan-BSD native targets.  NetBSD and OpenBSD also accept
LWP IDs for ptrace requests to fetch per-thread state.

gdb/ChangeLog:

	* amd64bsd-nat.c (amd64bsd_fetch_inferior_registers): Use
	get_ptrace_pid.
	(amd64bsd_store_inferior_registers): Use get_ptrace_pid.
	(amd64bsd_dr_get): Use get_ptrace_pid.
	(amd64bsd_dr_set): Use get_ptrace_pid.
	* i386bsd-nat.c (i386bsd_fetch_inferior_registers): Use get_ptrace_pid.
	(i386bsd_store_inferior_registers): Use get_ptrace_pid.
	(i386bsd_dr_get): Use get_ptrace_pid.
	(i386bsd_dr_set): Use get_ptrace_pid.
	* inf-ptrace.c (get_ptrace_pid): Export.
	* inf-ptrace.h (get_ptrace_pid): Declare.
	* ppcfbsd-nat.c (ppcfbsd_fetch_inferior_registers): Use lwp id.
	(ppcfbsd_store_inferior_registers): Use lwp id.

6 files changed, 55 insertions, 34 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 400305a..0d9a7fb 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,21 @@
 2016-01-19  John Baldwin  <jhb@FreeBSD.org>
 
+	* amd64bsd-nat.c (amd64bsd_fetch_inferior_registers): Use
+	get_ptrace_pid.
+	(amd64bsd_store_inferior_registers): Use get_ptrace_pid.
+	(amd64bsd_dr_get): Use get_ptrace_pid.
+	(amd64bsd_dr_set): Use get_ptrace_pid.
+	* i386bsd-nat.c (i386bsd_fetch_inferior_registers): Use get_ptrace_pid.
+	(i386bsd_store_inferior_registers): Use get_ptrace_pid.
+	(i386bsd_dr_get): Use get_ptrace_pid.
+	(i386bsd_dr_set): Use get_ptrace_pid.
+	* inf-ptrace.c (get_ptrace_pid): Export.
+	* inf-ptrace.h (get_ptrace_pid): Declare.
+	* ppcfbsd-nat.c (ppcfbsd_fetch_inferior_registers): Use lwp id.
+	(ppcfbsd_store_inferior_registers): Use lwp id.
+
+2016-01-19  John Baldwin  <jhb@FreeBSD.org>
+
 	* fbsd_tdep.c (fbsd_core_pid_to_str): New function.
 	(fbsd_core_thread_name): New function.
 	(fbsd_init_abi): Add "core_pid_to_str" gdbarch method.
diff --git a/gdb/amd64bsd-nat.c b/gdb/amd64bsd-nat.c
index aa79c13..fb7e4fa 100644
--- a/gdb/amd64bsd-nat.c
+++ b/gdb/amd64bsd-nat.c
@@ -52,7 +52,7 @@ amd64bsd_fetch_inferior_registers (struct target_ops *ops,
     {
       struct reg regs;
 
-      if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 	perror_with_name (_("Couldn't get registers"));
 
@@ -70,7 +70,7 @@ amd64bsd_fetch_inferior_registers (struct target_ops *ops,
       if (amd64bsd_xsave_len != 0)
 	{
 	  xstateregs = alloca (amd64bsd_xsave_len);
-	  if (ptrace (PT_GETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_GETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 	    perror_with_name (_("Couldn't get extended state status"));
 
@@ -79,7 +79,7 @@ amd64bsd_fetch_inferior_registers (struct target_ops *ops,
 	}
 #endif
 
-      if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't get floating point status"));
 
@@ -100,13 +100,13 @@ amd64bsd_store_inferior_registers (struct target_ops *ops,
     {
       struct reg regs;
 
-      if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
         perror_with_name (_("Couldn't get registers"));
 
       amd64_collect_native_gregset (regcache, &regs, regnum);
 
-      if (ptrace (PT_SETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_SETREGS, get_ptrace_pid (inferior_ptid),
 	          (PTRACE_TYPE_ARG3) &regs, 0) == -1)
         perror_with_name (_("Couldn't write registers"));
 
@@ -123,26 +123,26 @@ amd64bsd_store_inferior_registers (struct target_ops *ops,
       if (amd64bsd_xsave_len != 0)
 	{
 	  xstateregs = alloca (amd64bsd_xsave_len);
-	  if (ptrace (PT_GETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_GETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 	    perror_with_name (_("Couldn't get extended state status"));
 
 	  amd64_collect_xsave (regcache, regnum, xstateregs, 0);
 
-	  if (ptrace (PT_SETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_SETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, amd64bsd_xsave_len) == -1)
 	    perror_with_name (_("Couldn't write extended state status"));
 	  return;
 	}
 #endif
 
-      if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't get floating point status"));
 
       amd64_collect_fxsave (regcache, regnum, &fpregs);
 
-      if (ptrace (PT_SETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_SETFPREGS, get_ptrace_pid (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't write floating point status"));
     }
@@ -172,7 +172,7 @@ amd64bsd_dr_get (ptid_t ptid, int regnum)
 {
   struct dbreg dbregs;
 
-  if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETDBREGS, get_ptrace_pid (inferior_ptid),
 	      (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't read debug registers"));
 
@@ -184,7 +184,7 @@ amd64bsd_dr_set (int regnum, unsigned long value)
 {
   struct dbreg dbregs;
 
-  if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETDBREGS, get_ptrace_pid (inferior_ptid),
               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't get debug registers"));
 
@@ -195,7 +195,7 @@ amd64bsd_dr_set (int regnum, unsigned long value)
 
   DBREG_DRX ((&dbregs), regnum) = value;
 
-  if (ptrace (PT_SETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_SETDBREGS, get_ptrace_pid (inferior_ptid),
               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't write debug registers"));
 }
diff --git a/gdb/i386bsd-nat.c b/gdb/i386bsd-nat.c
index 71f962c..5d45c33 100644
--- a/gdb/i386bsd-nat.c
+++ b/gdb/i386bsd-nat.c
@@ -138,7 +138,7 @@ i386bsd_fetch_inferior_registers (struct target_ops *ops,
     {
       struct reg regs;
 
-      if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &regs, 0) == -1)
 	perror_with_name (_("Couldn't get registers"));
 
@@ -160,7 +160,7 @@ i386bsd_fetch_inferior_registers (struct target_ops *ops,
 	  char *xstateregs;
 
 	  xstateregs = alloca (i386bsd_xsave_len);
-	  if (ptrace (PT_GETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_GETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 	    perror_with_name (_("Couldn't get extended state status"));
 
@@ -171,7 +171,7 @@ i386bsd_fetch_inferior_registers (struct target_ops *ops,
       
 #ifdef HAVE_PT_GETXMMREGS
       if (have_ptrace_xmmregs != 0
-	  && ptrace(PT_GETXMMREGS, ptid_get_pid (inferior_ptid),
+	  && ptrace(PT_GETXMMREGS, get_ptrace_pid (inferior_ptid),
 		    (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 	{
 	  have_ptrace_xmmregs = 1;
@@ -181,7 +181,7 @@ i386bsd_fetch_inferior_registers (struct target_ops *ops,
 	{
 	  have_ptrace_xmmregs = 0;
 #endif
-          if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+          if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	    perror_with_name (_("Couldn't get floating point status"));
 
@@ -203,13 +203,13 @@ i386bsd_store_inferior_registers (struct target_ops *ops,
     {
       struct reg regs;
 
-      if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETREGS, get_ptrace_pid (inferior_ptid),
                   (PTRACE_TYPE_ARG3) &regs, 0) == -1)
         perror_with_name (_("Couldn't get registers"));
 
       i386bsd_collect_gregset (regcache, &regs, regnum);
 
-      if (ptrace (PT_SETREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_SETREGS, get_ptrace_pid (inferior_ptid),
 	          (PTRACE_TYPE_ARG3) &regs, 0) == -1)
         perror_with_name (_("Couldn't write registers"));
 
@@ -230,13 +230,13 @@ i386bsd_store_inferior_registers (struct target_ops *ops,
 	  char *xstateregs;
 
 	  xstateregs = alloca (i386bsd_xsave_len);
-	  if (ptrace (PT_GETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_GETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, 0) == -1)
 	    perror_with_name (_("Couldn't get extended state status"));
 
 	  i387_collect_xsave (regcache, -1, xstateregs, 0);
 
-	  if (ptrace (PT_SETXSTATE, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_SETXSTATE, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xstateregs, i386bsd_xsave_len) == -1)
 	    perror_with_name (_("Couldn't write extended state status"));
 	  return;
@@ -245,14 +245,14 @@ i386bsd_store_inferior_registers (struct target_ops *ops,
 
 #ifdef HAVE_PT_GETXMMREGS
       if (have_ptrace_xmmregs != 0
-	  && ptrace(PT_GETXMMREGS, ptid_get_pid (inferior_ptid),
+	  && ptrace(PT_GETXMMREGS, get_ptrace_pid (inferior_ptid),
 		    (PTRACE_TYPE_ARG3) xmmregs, 0) == 0)
 	{
 	  have_ptrace_xmmregs = 1;
 
 	  i387_collect_fxsave (regcache, regnum, xmmregs);
 
-	  if (ptrace (PT_SETXMMREGS, ptid_get_pid (inferior_ptid),
+	  if (ptrace (PT_SETXMMREGS, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) xmmregs, 0) == -1)
             perror_with_name (_("Couldn't write XMM registers"));
 	}
@@ -260,13 +260,13 @@ i386bsd_store_inferior_registers (struct target_ops *ops,
 	{
 	  have_ptrace_xmmregs = 0;
 #endif
-          if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+          if (ptrace (PT_GETFPREGS, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	    perror_with_name (_("Couldn't get floating point status"));
 
           i387_collect_fsave (regcache, regnum, &fpregs);
 
-          if (ptrace (PT_SETFPREGS, ptid_get_pid (inferior_ptid),
+          if (ptrace (PT_SETFPREGS, get_ptrace_pid (inferior_ptid),
 		      (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	    perror_with_name (_("Couldn't write floating point status"));
 #ifdef HAVE_PT_GETXMMREGS
@@ -305,7 +305,7 @@ i386bsd_dr_get (ptid_t ptid, int regnum)
 {
   struct dbreg dbregs;
 
-  if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETDBREGS, get_ptrace_pid (inferior_ptid),
 	      (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't read debug registers"));
 
@@ -317,7 +317,7 @@ i386bsd_dr_set (int regnum, unsigned int value)
 {
   struct dbreg dbregs;
 
-  if (ptrace (PT_GETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETDBREGS, get_ptrace_pid (inferior_ptid),
               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't get debug registers"));
 
@@ -328,7 +328,7 @@ i386bsd_dr_set (int regnum, unsigned int value)
 
   DBREG_DRX ((&dbregs), regnum) = value;
 
-  if (ptrace (PT_SETDBREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_SETDBREGS, get_ptrace_pid (inferior_ptid),
               (PTRACE_TYPE_ARG3) &dbregs, 0) == -1)
     perror_with_name (_("Couldn't write debug registers"));
 }
diff --git a/gdb/inf-ptrace.c b/gdb/inf-ptrace.c
index 8f8f4ee..329d8fb 100644
--- a/gdb/inf-ptrace.c
+++ b/gdb/inf-ptrace.c
@@ -304,7 +304,7 @@ inf_ptrace_interrupt (struct target_ops *self, ptid_t ptid)
 /* Return which PID to pass to ptrace in order to observe/control the
    tracee identified by PTID.  */
 
-static pid_t
+pid_t
 get_ptrace_pid (ptid_t ptid)
 {
   pid_t pid;
diff --git a/gdb/inf-ptrace.h b/gdb/inf-ptrace.h
index ec40590..0a26720 100644
--- a/gdb/inf-ptrace.h
+++ b/gdb/inf-ptrace.h
@@ -33,4 +33,9 @@ extern struct target_ops *
   inf_ptrace_trad_target (CORE_ADDR (*register_u_offset)
 					(struct gdbarch *, int, int));
 
+/* Return which PID to pass to ptrace in order to observe/control the
+   tracee identified by PTID.  */
+
+extern pid_t get_ptrace_pid (ptid_t);
+
 #endif
diff --git a/gdb/ppcfbsd-nat.c b/gdb/ppcfbsd-nat.c
index b41ed70..999e383 100644
--- a/gdb/ppcfbsd-nat.c
+++ b/gdb/ppcfbsd-nat.c
@@ -121,7 +121,7 @@ ppcfbsd_fetch_inferior_registers (struct target_ops *ops,
 {
   gdb_gregset_t regs;
 
-  if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETREGS, ptid_get_lwp (inferior_ptid),
 	      (PTRACE_TYPE_ARG3) &regs, 0) == -1)
     perror_with_name (_("Couldn't get registers"));
 
@@ -132,7 +132,7 @@ ppcfbsd_fetch_inferior_registers (struct target_ops *ops,
       const struct regset *fpregset = ppc_fbsd_fpregset ();
       gdb_fpregset_t fpregs;
 
-      if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETFPREGS, ptid_get_lwp (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't get FP registers"));
 
@@ -149,13 +149,13 @@ ppcfbsd_store_inferior_registers (struct target_ops *ops,
 {
   gdb_gregset_t regs;
 
-  if (ptrace (PT_GETREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_GETREGS, ptid_get_lwp (inferior_ptid),
 	      (PTRACE_TYPE_ARG3) &regs, 0) == -1)
     perror_with_name (_("Couldn't get registers"));
 
   fill_gregset (regcache, &regs, regno);
 
-  if (ptrace (PT_SETREGS, ptid_get_pid (inferior_ptid),
+  if (ptrace (PT_SETREGS, ptid_get_lwp (inferior_ptid),
 	      (PTRACE_TYPE_ARG3) &regs, 0) == -1)
     perror_with_name (_("Couldn't write registers"));
 
@@ -163,13 +163,13 @@ ppcfbsd_store_inferior_registers (struct target_ops *ops,
     {
       gdb_fpregset_t fpregs;
 
-      if (ptrace (PT_GETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_GETFPREGS, ptid_get_lwp (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't get FP registers"));
 
       fill_fpregset (regcache, &fpregs, regno);
 
-      if (ptrace (PT_SETFPREGS, ptid_get_pid (inferior_ptid),
+      if (ptrace (PT_SETFPREGS, ptid_get_lwp (inferior_ptid),
 		  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	perror_with_name (_("Couldn't set FP registers"));
     }