Bug 1383592

+++ This bug was initially created as a clone of Bug #1370931 +++

Description of problem:
Very similar to how upcall events are allocated by gfapi and returned to the applications, glfs_realpath() uses malloc(). 

Version-Release number of selected component (if applicable):
all

How reproducible:
Compile an application that calls glfs_realpath() and have the function allocate the memory on behalf of the application. If the application uses a different memory allocated (i.e. jemalloc), free() will not work correctly and can cause segfaults.

Additional info:
See http://review.gluster.org/14701 for a more complete description.

--- Additional comment from Worker Ant on 2016-08-28 16:36:33 CEST ---

REVIEW: http://review.gluster.org/15332 (gfapi: warn when glfs_realpath() returned malloc'd memory) posted (#1) for review on master by Niels de Vos (ndevos)

--- Additional comment from Worker Ant on 2016-08-29 13:52:54 CEST ---

REVIEW: http://review.gluster.org/15332 (gfapi: warn when glfs_realpath() returned malloc'd memory) posted (#2) for review on master by Niels de Vos (ndevos)

--- Additional comment from Worker Ant on 2016-08-29 22:05:12 CEST ---

REVIEW: http://review.gluster.org/15332 (gfapi: warn when glfs_realpath() returned malloc'd memory) posted (#3) for review on master by Niels de Vos (ndevos)

--- Additional comment from Worker Ant on 2016-09-13 13:40:25 CEST ---

REVIEW: http://review.gluster.org/15332 (gfapi: warn when glfs_realpath() returned malloc'd memory) posted (#4) for review on master by Niels de Vos (ndevos)

--- Additional comment from Worker Ant on 2016-09-30 13:10:24 CEST ---

REVIEW: http://review.gluster.org/15332 (gfapi: warn when glfs_realpath() returned malloc'd memory) posted (#5) for review on master by Niels de Vos (ndevos)

--- Additional comment from Worker Ant on 2016-09-30 15:49:11 CEST ---

REVIEW: http://review.gluster.org/15332 (gfapi: warn when glfs_realpath() returned malloc'd memory) posted (#6) for review on master by Niels de Vos (ndevos)

--- Additional comment from Worker Ant on 2016-10-10 15:33:38 CEST ---

REVIEW: http://review.gluster.org/15332 (gfapi: warn when glfs_realpath() returned malloc'd memory) posted (#7) for review on master by Niels de Vos (ndevos)

--- Additional comment from Worker Ant on 2016-10-11 09:14:04 CEST ---

COMMIT: http://review.gluster.org/15332 committed in master by Niels de Vos (ndevos) 
------
commit 85e959052148ec481823d55c8b91cdee36da2b43
Author: Niels de Vos <ndevos>
Date:   Tue Sep 13 09:03:56 2016 +0200

    gfapi: warn when glfs_realpath() returned malloc'd memory
    
    glfs_realpath() may return memory allocated with malloc(). Depending on
    the memory allocator that the application uses, calling free() on the
    returned string can cause segmentation faults or other problems.
    
    Functions that allocate memory, need to match the free'ing of the same
    memory allocator and memory accounting. glibc/malloc and jemalloc/free
    do not match together (other allocators could probably trigger these
    problems as well).
    
    Applications need to provide a pre-allocated buffer, or in case
    glfs_realpath() allocates the memory, glfs_free() should be used to free
    it.
    
    Change-Id: I5d721a7425674aa700db8a7a436cbedb95a5927f
    BUG: 1370931
    Signed-off-by: Niels de Vos <ndevos>
    Reviewed-on: http://review.gluster.org/15332
    CentOS-regression: Gluster Build System <jenkins.org>
    Smoke: Gluster Build System <jenkins.org>
    NetBSD-regression: NetBSD Build System <jenkins.org>
    Reviewed-by: Kaleb KEITHLEY <kkeithle>