[PATCH V3][PR gdb/17903] Implement to_pid_to_exec_file for solaris

[Brian Vandenberg <phantall at gmail dot com>]

This patch is to address an issue in Solaris, bug 17903.

This is my third submission for this issue with changes requested by
Pedro Alvez / Joel Brobecker.

Problem:

When attaching to a process by PID the current implementation in
gdb/procfs.c leaves "to_pid_to_exec_file" at the default -- a stub
function that returns NULL.

This causes symbols not to load when attaching, forcing the user to
either attach by specifying the path on the command line or inside
gdb.  After specifying the file inside gdb it's also necessary to
manually load symbolic information.

The proposed change resembles the implementation in gdb/linux-nat.c.
Pedro indicated Solaris is likely the only OS affected by this code &
still needs support; at his suggestion I tailored this change for
Solaris


I cannot easily run the test suite against these changes right now.
If this gets rejected based on that, I'll see about getting something
setup at home to run the tests when I have time.

----

note: this patch was tested against 8.1.1.  In its current form this
patch cannot be used against 8.2 / master, however it looks like it
won't take much to apply the same change against the new C++ procfs
interface.

-brian

ps, my assignment/release forms were completed/received 10/30/2017

Attachment: gdb-17903-patch, revised.txt
Description: Text document