[newlib-cygwin] Add a /proc/<pid>/environ proc file handler, analogous to /proc/<pid>/cmdline.

[Corinna Vinschen <corinna at sourceware dot org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=5bebfa17c5e71338fb77b7b737cee0f8ed04f077

commit 5bebfa17c5e71338fb77b7b737cee0f8ed04f077
Author: Erik M. Bray <erik.bray@lri.fr>
Date:   Tue Jan 10 16:03:10 2017 +0100

    Add a /proc/<pid>/environ proc file handler, analogous to /proc/<pid>/cmdline.

Diff:
---
 winsup/cygwin/fhandler_process.cc | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/winsup/cygwin/fhandler_process.cc b/winsup/cygwin/fhandler_process.cc
index 5f530a2..bbb44fa 100644
--- a/winsup/cygwin/fhandler_process.cc
+++ b/winsup/cygwin/fhandler_process.cc
@@ -49,6 +49,7 @@ static off_t format_process_ctty (void *, char *&);
 static off_t format_process_fd (void *, char *&);
 static off_t format_process_mounts (void *, char *&);
 static off_t format_process_mountinfo (void *, char *&);
+static off_t format_process_environ (void *, char *&);
 
 static const virt_tab_t process_tab[] =
 {
@@ -57,6 +58,7 @@ static const virt_tab_t process_tab[] =
   { _VN ("cmdline"),    FH_PROCESS,   virt_file,      format_process_cmdline },
   { _VN ("ctty"),       FH_PROCESS,   virt_file,      format_process_ctty },
   { _VN ("cwd"),        FH_PROCESS,   virt_symlink,   format_process_cwd },
+  { _VN ("environ"),    FH_PROCESS,   virt_file,      format_process_environ },
   { _VN ("exe"),        FH_PROCESS,   virt_symlink,   format_process_exename },
   { _VN ("exename"),    FH_PROCESS,   virt_file,      format_process_exename },
   { _VN ("fd"),         FH_PROCESSFD, virt_directory, format_process_fd },
@@ -570,6 +572,26 @@ format_process_winexename (void *data, char *&destbuf)
   return len;
 }
 
+static off_t
+format_process_environ (void *data, char *&destbuf)
+{
+  _pinfo *p = (_pinfo *) data;
+  size_t fs;
+
+  if (destbuf)
+    {
+      cfree (destbuf);
+      destbuf = NULL;
+    }
+  destbuf = p->environ (fs);
+  if (!destbuf || !*destbuf)
+    {
+      destbuf = cstrdup ("<defunct>");
+      fs = strlen (destbuf) + 1;
+    }
+  return fs;
+}
+
 struct heap_info
 {
   struct heap