build: export minimum symbols from xlators for correct resolution

We've been lucky that we haven't had any symbol collisions until now.
Now we have a collision between the snapview-client's svc_lookup() and
libntirpc's svc_lookup() with nfs-ganesha's FSAL_GLUSTER and libgfapi.

As a short term solution all the snapview-client's FOP methods were
changed to static scope. See http://review.gluster.org/11805. This
works in snapview-client because all the FOP methods are defined in
a single source file. This solution doesn't work for other xlators
with FOP methods defined in multiple source files.

To address this we link with libtool's '-export-symbols $symbol-file'
(a wrapper around `ld --version-script ...` --- on linux anyway) and
only export the minimum required symbols from the xlator sharedlib.

N.B. the libtool man page says that the symbol file should be named
foo.sym, thus the rename of *.exports to *.sym. While foo.exports
worked, we will follow the documentation.

Signed-off-by: Kaleb S. KEITHLEY <kkeithle@redhat.com>
BUG: 1248669
Change-Id: I1de68b3e3be58ae690d8bfb2168bfc019983627c
Reviewed-on: http://review.gluster.org/11814
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: soumya k <skoduri@redhat.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>

2 files changed, 104 insertions, 1 deletions

diff --git a/xlators/features/glupy/src/Makefile.am b/xlators/features/glupy/src/Makefile.am
index 2ac0d99cd5f..eadccf75c15 100644
--- a/xlators/features/glupy/src/Makefile.am
+++ b/xlators/features/glupy/src/Makefile.am
@@ -7,7 +7,7 @@ AM_CPPFLAGS = $(PYTHONDEV_CPPFLAGS) $(GF_CPPFLAGS) -I$(top_srcdir)/libglusterfs/
 AM_CFLAGS = $(PYTHONDEV_CFLAGS) -Wall -fno-strict-aliasing -DGLUSTER_PYTHON_PATH=\"$(glupydir)\" -DPATH_GLUSTERFS_GLUPY_MODULE=\"${xlatordir}/glupy${shrext_cmds}\" $(GF_CFLAGS)
 
 # Flags to build glupy.so with
-glupy_la_LDFLAGS = $(PYTHONDEV_LDFLAGS) -module -avoid-version -nostartfiles
+glupy_la_LDFLAGS = $(PYTHONDEV_LDFLAGS) -module -avoid-version -nostartfiles -export-symbols $(top_srcdir)/xlators/features/glupy/src/glupy.sym
 glupy_la_SOURCES = glupy.c
 glupy_la_LIBADD = $(top_builddir)/libglusterfs/src/libglusterfs.la \
 	 -lpthread -l$(BUILD_PYTHON_LIB)
@@ -22,3 +22,5 @@ pyglupy_PYTHON = __init__.py
 SUBDIRS = glupy
 
 CLEANFILES =
+
+EXTRA_DIST = glupy.sym
diff --git a/xlators/features/glupy/src/glupy.sym b/xlators/features/glupy/src/glupy.sym
new file mode 100644
index 00000000000..55d9a300108
--- /dev/null
+++ b/xlators/features/glupy/src/glupy.sym
@@ -0,0 +1,101 @@
+init
+fini
+fops
+cbks
+options
+notify
+mem_acct_init
+reconfigure
+dumpops
+set_lookup_fop
+set_lookup_cbk
+set_create_fop
+set_create_cbk
+set_open_fop
+set_open_cbk
+set_readv_fop
+set_readv_cbk
+set_writev_fop
+set_writev_cbk
+set_opendir_fop
+set_opendir_cbk
+set_readdir_fop
+set_readdir_cbk
+set_readdirp_fop
+set_readdirp_cbk
+set_stat_fop
+set_stat_cbk
+set_fstat_fop
+set_fstat_cbk
+set_statfs_fop
+set_statfs_cbk
+set_setxattr_fop
+set_setxattr_cbk
+set_getxattr_fop
+set_getxattr_cbk
+set_fsetxattr_fop
+set_fsetxattr_cbk
+set_fgetxattr_fop
+set_fgetxattr_cbk
+set_removexattr_fop
+set_removexattr_cbk
+set_fremovexattr_fop
+set_fremovexattr_cbk
+set_link_fop
+set_link_cbk
+set_symlink_fop
+set_symlink_cbk
+set_readlink_fop
+set_readlink_cbk
+set_unlink_fop
+set_unlink_cbk
+set_mkdir_fop
+set_mkdir_cbk
+set_rmdir_fop
+set_rmdir_cbk
+wind_lookup
+wind_create
+wind_open
+wind_readv
+wind_writev
+wind_opendir
+wind_readdir
+wind_readdirp
+wind_stat
+wind_fstat
+wind_statfs
+wind_setxattr
+wind_getxattr
+wind_fsetxattr
+wind_fgetxattr
+wind_removexattr
+wind_fremovexattr
+wind_link
+wind_symlink
+wind_readlink
+wind_unlink
+wind_mkdir
+wind_rmdir
+unwind_lookup
+unwind_create
+unwind_open
+unwind_readv
+unwind_writev
+unwind_opendir
+unwind_readdir
+unwind_readdirp
+unwind_stat
+unwind_fstat
+unwind_statfs
+unwind_setxattr
+unwind_getxattr
+unwind_fsetxattr
+unwind_fgetxattr
+unwind_removexattr
+unwind_fremovexattr
+unwind_link
+unwind_symlink
+unwind_readlink
+unwind_unlink
+unwind_mkdir
+unwind_rmdir