Hide getting at the current process's PID behind a target method.

From: Pedro Alves <palves@redhat.com>


---
 gdb/linux-nat.c |   18 ++++++++++++++++--
 gdb/remote.c    |   26 ++++++++++++++++++++++++++
 gdb/target.c    |    5 +++++
 gdb/target.h    |    4 ++++
 4 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 17236ec..1d06352 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -5007,6 +5007,16 @@ make_cleanup_target_file_close (int fd)
   return make_cleanup (do_target_file_close, fdp);
 }
 
+static int
+linux_nat_current_process_id (LONGEST *pid)
+{
+  if (!target_has_execution)
+    noprocess ();
+
+  *pid = ptid_get_pid (inferior_ptid);
+  return 0;
+}
+
 static void
 linux_nat_info_proc_cmd_1 (char *args, enum info_proc_what what, int from_tty)
 {
@@ -5038,11 +5048,13 @@ linux_nat_info_proc_cmd_1 (char *args, enum info_proc_what what, int from_tty)
 
   if (!explicit_pid)
     {
+      LONGEST tpid;
+
       if (!target_has_execution)
 	error (_("No current process: you must name one."));
-      if (current_inferior ()->fake_pid_p)
+      if (target_current_process_id (&tpid) == -1)
 	error (_("Can't determine the current process's PID: you must name one."));
-      pid = ptid_get_pid (inferior_ptid);
+      pid = tpid;
     }
 
   printf_filtered (_("process %ld\n"), pid);
@@ -6077,6 +6089,8 @@ linux_nat_add_target (struct target_ops *t)
   t->to_file_pread = linux_nat_file_pread;
   t->to_file_close = linux_nat_file_close;
 
+  t->to_current_process_id = linux_nat_current_process_id;
+
   /* We don't change the stratum; this target will sit at
      process_stratum and thread_db will set at thread_stratum.  This
      is a little strange, since this is a multi-threaded-capable
diff --git a/gdb/remote.c b/gdb/remote.c
index e78853c..2bd7d13 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -9779,6 +9779,30 @@ remote_supports_multi_process (void)
   return rs->extended && remote_multi_process_p (rs);
 }
 
+/* Return in *PID the current inferior's target process ID.  Returns 0
+   on success, and -1 if not possible to determine the target PID.
+   Throws an error if there is no current inferior.  */
+
+static int
+remote_current_process_id (LONGEST *pid)
+{
+  if (!target_has_execution)
+    noprocess ();
+
+  /* Add query to remote target side here if/when necessary.  */
+
+  /* Default to assuming there's a 1:1 mapping between RSP process ID
+     and target process ID.  */
+
+  /* With no multi-process extensions, we have nothing to fall back
+     to.  */
+  if (current_inferior ()->fake_pid_p)
+    return -1;
+
+  *pid = ptid_get_pid (inferior_ptid);
+  return 0;
+}
+
 int
 remote_supports_cond_tracepoints (void)
 {
@@ -10715,6 +10739,8 @@ Specify the serial device it is connected to\n\
   remote_ops.to_file_pread = remote_hostio_pread;
   remote_ops.to_file_close = remote_hostio_close;
   remote_ops.to_file_unlink = remote_hostio_unlink;
+
+  remote_ops.to_current_process_id = remote_current_process_id;
 }
 
 /* Set up the extended remote vector by making a copy of the standard
diff --git a/gdb/target.c b/gdb/target.c
index 74238a5..1422117 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -704,6 +704,8 @@ update_current_target (void)
       INHERIT (to_file_close, t);
       INHERIT (to_file_unlink, t);
 
+      INHERIT (to_current_process_id, t);
+
       INHERIT (to_magic, t);
       /* Do not inherit to_memory_map.  */
       /* Do not inherit to_flash_erase.  */
@@ -950,6 +952,9 @@ update_current_target (void)
   de_fault (to_file_unlink,
 	    (int (*) (const char *, int *))
 	    tcomplain);
+  de_fault (to_current_process_id,
+	    (int (*) (LONGEST *))
+	    tcomplain);
 
 #undef de_fault
 
diff --git a/gdb/target.h b/gdb/target.h
index 96176a5..449be04 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -821,6 +821,7 @@ struct target_ops
        occurs (and set *TARGET_ERRNO).  */
     int (*to_file_unlink) (const char *filename, int *target_errno);
 
+    int (*to_current_process_id) (LONGEST *pid);
     int to_magic;
     /* Need sub-structure for target machine related rather than comm related?
      */
@@ -1789,6 +1790,9 @@ extern void update_target_permissions (void);
 #define target_file_unlink(filename, target_errno)		\
   (*current_target.to_file_close) (filename, target_errno)
 
+#define target_current_process_id(PID)		\
+  (*current_target.to_current_process_id) (PID)
+
 
 /* Imported from machine dependent code.  */