[binutils-gdb] libctf: fix refcount leak in ctf_import

[Jose E.Marchesi <jemarch@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=ad613f1d0693e02bdc86047c479315d5f969e2f7

commit ad613f1d0693e02bdc86047c479315d5f969e2f7
Author: Nick Alcock <nick.alcock@oracle.com>
Date:   Tue Sep 17 06:59:31 2019 +0100

    libctf: fix refcount leak in ctf_import
    
    Calling ctf_import (fp, NULL) to cancel out a pre-existing import leaked
    the refcnt increment on the parent, so it could never be freed.
    
    New in v4.
    
    libctf/
    	* ctf-open.c (ctf_import): Do not leak a ctf_file_t ref on every
    	ctf_import after the first for a given file.

Diff:
---
 libctf/ChangeLog  | 5 +++++
 libctf/ctf-open.c | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/libctf/ChangeLog b/libctf/ChangeLog
index b7f12d8..982c335 100644
--- a/libctf/ChangeLog
+++ b/libctf/ChangeLog
@@ -1,5 +1,10 @@
 2019-09-23  Nick Alcock  <nick.alcock@oracle.com>
 
+	* ctf-open.c (ctf_import): Do not leak a ctf_file_t ref on every
+	ctf_import after the first for a given file.
+
+2019-09-23  Nick Alcock  <nick.alcock@oracle.com>
+
 	* ctf-impl.h (ctf_str_append_noerr): Declare.
 	* ctf-util.c (ctf_str_append_noerr): Define in terms of
 	ctf_str_append.
diff --git a/libctf/ctf-open.c b/libctf/ctf-open.c
index 4a95b7f..aedf390 100644
--- a/libctf/ctf-open.c
+++ b/libctf/ctf-open.c
@@ -1778,6 +1778,7 @@ ctf_import (ctf_file_t *fp, ctf_file_t *pfp)
 
   if (fp->ctf_parent != NULL)
     {
+      fp->ctf_parent->ctf_refcnt--;
       ctf_file_close (fp->ctf_parent);
       fp->ctf_parent = NULL;
     }
@@ -1793,6 +1794,7 @@ ctf_import (ctf_file_t *fp, ctf_file_t *pfp)
       fp->ctf_flags |= LCTF_CHILD;
       pfp->ctf_refcnt++;
     }
+
   fp->ctf_parent = pfp;
   return 0;
 }