Add common write_memory and read_memory NetBSD routines

Instead of sharing the native-only code with all BSDs with slightly
different semantics of the kernels, share the NetBSD-only behavior beteen
the NetBSD native and gdbserver setup.

NetBSD does not differentiate the address space I and D in the
operations (contrary to OpenBSD). NetBSD handles EACCES that integrates
with NetBSD specific PaX MPROTECT error handling.

Add a verbose message in the native client that an operation could be
cancelled due to PaX MPROTECT setup.

gdb/ChangeLog:

       * nat/netbsd-nat.c (write_memory, read_memory): Add.
       * nat/netbsd-nat.h (write_memory, read_memory): Likewise.
       * nbsd-nat.c (nbsd_nat_target::xfer_partial): Update.

gdbserver/ChangeLog:

       * netbsd-low.cc (netbsd_process_target::read_memory)
       (netbsd_process_target::write_memory): Update.

1 files changed, 22 insertions, 0 deletions

diff --git a/gdb/nat/netbsd-nat.h b/gdb/nat/netbsd-nat.h
index d77119b..594dec1 100644
--- a/gdb/nat/netbsd-nat.h
+++ b/gdb/nat/netbsd-nat.h
@@ -67,6 +67,28 @@ extern void enable_proc_events (pid_t pid);
 extern int qxfer_siginfo (pid_t pid, const char *annex, unsigned char *readbuf,
 			  unsigned const char *writebuf, CORE_ADDR offset,
 			  int len);
+
+/* Write gdb's LEN bytes from WRITEBUF and copy it to OFFSET in inferior
+   process' address space. The inferior is specified by PID.
+   Returns 0 on success or errno on failure and the number of bytes
+   on a successful transfer in XFERED_LEN.
+
+   This function assumes internally that the queried process is stopped and
+   traced.  */
+
+extern int write_memory (pid_t pid, unsigned const char *writebuf,
+			 CORE_ADDR offset, size_t len, size_t *xfered_len);
+
+/* Read inferior process's LEN bytes from OFFSET and copy it to WRITEBUF in
+   gdb's address space.
+   Returns 0 on success or errno on failure and the number of bytes
+   on a successful transfer in XFERED_LEN.
+
+   This function assumes internally that the queried process is stopped and
+   traced.  */
+
+extern int read_memory (pid_t pid, unsigned char *readbuf, CORE_ADDR offset,
+			size_t len, size_t *xfered_len);
 }
 
 #endif