[patch] Fix some plugin API issues in BFD

[Rafael Ávila de Espíndola <respindola at mozilla dot com>]

I recently updated a plugin to use the file descriptor directly. This 
worked fine in gold, but had two issues using bfd (nm and ar):

*) The filesize was not being set.
*) The code expected the claim_file callback to not seek.

That is not my understanding from reading the api documentation in 
http://gcc.gnu.org/wiki/whopr/driver, so the attached patch fixes both 
issues.

2010-02-08  Rafael Ávila de Espíndola <respindola@mozilla.com>

	* plugin.c (bfd_plugin_object_p): Correctly set the filesize
	and handle claim_file seeking.

Cheers,
Rafael

diff --git a/bfd/plugin.c b/bfd/plugin.c
index 30a4923..319ef50 100644
--- a/bfd/plugin.c
+++ b/bfd/plugin.c
@@ -251,7 +251,7 @@ bfd_plugin_object_p (bfd *abfd)
     {
       iobfd = abfd;
       file.offset = 0;
-      file.filesize = 0; /*FIXME*/
+      file.filesize = 0;
     }
 
   if (!iobfd->iostream && !bfd_open_file (iobfd))
@@ -259,8 +259,18 @@ bfd_plugin_object_p (bfd *abfd)
 
   file.fd = fileno ((FILE *) iobfd->iostream);
 
+  if (!abfd->my_archive)
+    {
+      struct stat stat_buf;
+      if (fstat (file.fd, &stat_buf))
+        return NULL;
+      file.filesize = stat_buf.st_size;
+    }
+
   file.handle = abfd;
+  off_t cur_offset = lseek(file.fd, 0, SEEK_CUR);
   claim_file (&file, &claimed);
+  lseek(file.fd, cur_offset, SEEK_SET);
   if (!claimed)
     return NULL;