pyzfs: python3 support (build system)

Almost all of the Python code in the respository has been updated
to be compatibile with Python 2.6, Python 3.4, or newer.  The only
exceptions are arc_summery3.py which requires Python 3, and pyzfs
which requires at least Python 2.7.  This allows us to maintain a
single version of the code and support most default versions of
python.  This change does the following:

* Sets the default shebang for all Python scripts to python3.  If
  only Python 2 is available, then at install time scripts which
  are compatible with Python 2 will have their shebangs replaced
  with /usr/bin/python.  This is done for compatibility until
  Python 2 goes end of life.  Since only the installed versions
  are changed this means Python 3 must be installed on the system
  for test-runner when testing in-tree.

* Added --with-python=<2|3|3.4,etc> configure option which sets
  the PYTHON environment variable to target a specific python
  version.  By default the newest installed version of Python
  will be used or the preferred distribution version when
  creating pacakges.

* Fixed --enable-pyzfs configure checks so they are run when
  --enable-pyzfs=check and --enable-pyzfs=yes.

* Enabled pyzfs for Python 3.4 and newer, which is now supported.

* Renamed pyzfs package to python<VERSION>-pyzfs and updated to
  install in the appropriate site location.  For example, when
  building with --with-python=3.4 a python34-pyzfs will be
  created which installs in /usr/lib/python3.4/site-packages/.

* Renamed the following python scripts according to the Fedora
  guidance for packaging utilities in /bin

  - dbufstat.py     -> dbufstat
  - arcstat.py      -> arcstat
  - arc_summary.py  -> arc_summary
  - arc_summary3.py -> arc_summary3

* Updated python-cffi package name.  On CentOS 6, CentOS 7, and
  Amazon Linux it's called python-cffi, not python2-cffi.  For
  Python3 it's called python3-cffi or python3x-cffi.

* Install one version of arc_summary.  Depending on the version
  of Python available install either arc_summary2 or arc_summary3
  as arc_summary.  The user output is only slightly different.

Reviewed-by: John Ramsden <johnramsden@riseup.net>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #8096

.gitignore

@@ -22,6 +22,8 @@
 *.swp
 *.gcno
 *.gcda
+*.pyc
+*.pyo
 .deps
 .libs
 .dirstamp

cmd/arc_summary/Makefile.am

@@ -1 +1,13 @@
-dist_bin_SCRIPTS = arc_summary.py arc_summary3.py
+EXTRA_DIST = arc_summary2 arc_summary3
+
+if USING_PYTHON_2
+dist_bin_SCRIPTS = arc_summary2
+install-exec-hook:
+	mv $(DESTDIR)$(bindir)/arc_summary2 $(DESTDIR)$(bindir)/arc_summary
+endif
+
+if USING_PYTHON_3
+dist_bin_SCRIPTS = arc_summary3
+install-exec-hook:
+	mv $(DESTDIR)$(bindir)/arc_summary3 $(DESTDIR)$(bindir)/arc_summary
+endif

cmd/arc_summary/arc_summary2

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2
 #
 # $Id: arc_summary.pl,v 388:e27800740aa2 2011-07-08 02:53:29Z jhell $
 #
@@ -35,6 +35,8 @@
 # Note some of this code uses older code (eg getopt instead of argparse,
 # subprocess.Popen() instead of subprocess.run()) because we need to support
 # some very old versions of Python.
+#
+
 """Print statistics on the ZFS Adjustable Replacement Cache (ARC)
 
 Provides basic information on the ARC, its efficiency, the L2ARC (if present),
@@ -1005,7 +1007,7 @@ def zfs_header():
 def usage():
     """Print usage information"""
 
-    sys.stdout.write("Usage: arc_summary.py [-h] [-a] [-d] [-p PAGE]\n\n")
+    sys.stdout.write("Usage: arc_summary [-h] [-a] [-d] [-p PAGE]\n\n")
     sys.stdout.write("\t -h, --help           : "
                      "Print this help message and exit\n")
     sys.stdout.write("\t -a, --alternate      : "
@@ -1018,10 +1020,10 @@ def usage():
                      "should be an integer between 1 and " +
                      str(len(unSub)) + "\n\n")
     sys.stdout.write("Examples:\n")
-    sys.stdout.write("\tarc_summary.py -a\n")
+    sys.stdout.write("\tarc_summary -a\n")
-    sys.stdout.write("\tarc_summary.py -p 4\n")
+    sys.stdout.write("\tarc_summary -p 4\n")
-    sys.stdout.write("\tarc_summary.py -ad\n")
+    sys.stdout.write("\tarc_summary -ad\n")
-    sys.stdout.write("\tarc_summary.py --page=2\n")
+    sys.stdout.write("\tarc_summary --page=2\n")
 
 
 def main():

cmd/arc_summary/arc_summary3

@@ -346,7 +346,7 @@ def get_version(request):
         error_msg = '(ERROR: "{0}" requested)'.format(request)
         return error_msg
 
-    # The original arc_summary.py called /sbin/modinfo/{spl,zfs} to get
+    # The original arc_summary called /sbin/modinfo/{spl,zfs} to get
     # the version information. We switch to /sys/module/{spl,zfs}/version
     # to make sure we get what is really loaded in the kernel
     command = ["cat", "/sys/module/{0}/version".format(request)]
@@ -374,7 +374,7 @@ def print_header():
     """
 
     # datetime is now recommended over time but we keep the exact formatting
-    # from the older version of arc_summary.py in case there are scripts
+    # from the older version of arc_summary in case there are scripts
     # that expect it in this way
     daydate = time.strftime(DATE_FORMAT)
     spc_date = LINE_LENGTH-len(daydate)
@@ -586,7 +586,7 @@ def section_archits(kstats_dict):
 
     # For some reason, anon_hits can turn negative, which is weird. Until we
     # have figured out why this happens, we just hide the problem, following
-    # the behavior of the original arc_summary.py
+    # the behavior of the original arc_summary.
     if anon_hits >= 0:
         prt_i2('Anonymously used:',
                f_perc(anon_hits, arc_stats['hits']), f_hits(anon_hits))

cmd/arcstat/Makefile.am

@@ -1 +1,13 @@
-dist_bin_SCRIPTS = arcstat.py
+dist_bin_SCRIPTS = arcstat
+
+#
+# The arcstat script is compatibile with both Python 2.6 and 3.4.
+# As such the python 3 shebang can be replaced at install time when
+# targeting a python 2 system.  This allows us to maintain a single
+# version of the source.
+#
+if USING_PYTHON_2
+install-exec-hook:
+	sed --in-place 's|^#!/usr/bin/python3|#!/usr/bin/python2|' \
+	    $(DESTDIR)$(bindir)/arcstat
+endif

cmd/arcstat/arcstat

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 #
 # Print out ZFS ARC Statistics exported via kstat(1)
 # For a definition of fields, or usage, use arctstat.pl -v
@@ -42,7 +42,8 @@
 # @hdr is the array of fields that needs to be printed, so we
 # just iterate over this array and print the values using our pretty printer.
 #
-
+# This script must remain compatible with Python 2.6+ and Python 3.4+.
+#
 
 import sys
 import time
@@ -109,7 +110,7 @@ opfile = None
 sep = "  "              # Default separator is 2 spaces
 version = "0.4"
 l2exist = False
-cmd = ("Usage: arcstat.py [-hvx] [-f fields] [-o file] [-s string] [interval "
+cmd = ("Usage: arcstat [-hvx] [-f fields] [-o file] [-s string] [interval "
        "[count]]\n")
 cur = {}
 d = {}
@@ -138,10 +139,10 @@ def usage():
     sys.stderr.write("\t -s : Override default field separator with custom "
                      "character or string\n")
     sys.stderr.write("\nExamples:\n")
-    sys.stderr.write("\tarcstat.py -o /tmp/a.log 2 10\n")
+    sys.stderr.write("\tarcstat -o /tmp/a.log 2 10\n")
-    sys.stderr.write("\tarcstat.py -s \",\" -o /tmp/a.log 2 10\n")
+    sys.stderr.write("\tarcstat -s \",\" -o /tmp/a.log 2 10\n")
-    sys.stderr.write("\tarcstat.py -v\n")
+    sys.stderr.write("\tarcstat -v\n")
-    sys.stderr.write("\tarcstat.py -f time,hit%,dh%,ph%,mh% 1\n")
+    sys.stderr.write("\tarcstat -f time,hit%,dh%,ph%,mh% 1\n")
     sys.stderr.write("\n")
 
     sys.exit(1)

cmd/dbufstat/Makefile.am

@@ -1 +1,13 @@
-dist_bin_SCRIPTS = dbufstat.py
+dist_bin_SCRIPTS = dbufstat
+
+#
+# The dbufstat script is compatibile with both Python 2.6 and 3.4.
+# As such the python 3 shebang can be replaced at install time when
+# targeting a python 2 system.  This allows us to maintain a single
+# version of the source.
+#
+if USING_PYTHON_2
+install-exec-hook:
+	sed --in-place 's|^#!/usr/bin/python3|#!/usr/bin/python2|' \
+	    $(DESTDIR)$(bindir)/dbufstat
+endif

cmd/dbufstat/dbufstat

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 #
 # Print out statistics for all cached dmu buffers.  This information
 # is available through the dbufs kstat and may be post-processed as
@@ -27,6 +27,8 @@
 # Copyright (C) 2013 Lawrence Livermore National Security, LLC.
 # Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
 #
+# This script must remain compatible with Python 2.6+ and Python 3.4+.
+#
 
 import sys
 import getopt
@@ -106,7 +108,7 @@ cols = {
 hdr = None
 xhdr = None
 sep = "  "  # Default separator is 2 spaces
-cmd = ("Usage: dbufstat.py [-bdhnrtvx] [-i file] [-f fields] [-o file] "
+cmd = ("Usage: dbufstat [-bdhnrtvx] [-i file] [-f fields] [-o file] "
        "[-s string] [-F filter]\n")
 raw = 0
 
@@ -167,11 +169,11 @@ def usage():
                      "character or string\n")
     sys.stderr.write("\t -F : Filter output by value or regex\n")
     sys.stderr.write("\nExamples:\n")
-    sys.stderr.write("\tdbufstat.py -d -o /tmp/d.log\n")
+    sys.stderr.write("\tdbufstat -d -o /tmp/d.log\n")
-    sys.stderr.write("\tdbufstat.py -t -s \",\" -o /tmp/t.log\n")
+    sys.stderr.write("\tdbufstat -t -s \",\" -o /tmp/t.log\n")
-    sys.stderr.write("\tdbufstat.py -v\n")
+    sys.stderr.write("\tdbufstat -v\n")
-    sys.stderr.write("\tdbufstat.py -d -f pool,object,objset,dsize,cached\n")
+    sys.stderr.write("\tdbufstat -d -f pool,object,objset,dsize,cached\n")
-    sys.stderr.write("\tdbufstat.py -bx -F dbc=1,objset=54,pool=testpool\n")
+    sys.stderr.write("\tdbufstat -bx -F dbc=1,objset=54,pool=testpool\n")
     sys.stderr.write("\n")
 
     sys.exit(1)

config/always-python.m4

@@ -0,0 +1,102 @@
+dnl #
+dnl # ZFS_AC_PYTHON_VERSION(version, [action-if-true], [action-if-false])
+dnl #
+dnl # Verify Python version
+dnl #
+AC_DEFUN([ZFS_AC_PYTHON_VERSION], [
+	ver_check=`$PYTHON -c "import sys; print (sys.version.split()[[0]] $1)"`
+	AS_IF([test "$ver_check" = "True"], [
+		m4_ifvaln([$2], [$2])
+	], [
+		m4_ifvaln([$3], [$3])
+	])
+])
+
+dnl #
+dnl # ZFS_AC_PYTHON_MODULE(module_name, [action-if-true], [action-if-false])
+dnl #
+dnl # Checks for Python module. Freely inspired by AX_PYTHON_MODULE
+dnl # https://www.gnu.org/software/autoconf-archive/ax_python_module.html
+dnl # Required by ZFS_AC_CONFIG_ALWAYS_PYZFS.
+dnl #
+AC_DEFUN([ZFS_AC_PYTHON_MODULE], [
+	PYTHON_NAME=`basename $PYTHON`
+	AC_MSG_CHECKING([for $PYTHON_NAME module: $1])
+	AS_IF([$PYTHON -c "import $1" 2>/dev/null], [
+		AC_MSG_RESULT(yes)
+		m4_ifvaln([$2], [$2])
+	], [
+		AC_MSG_RESULT(no)
+		m4_ifvaln([$3], [$3])
+	])
+])
+
+dnl #
+dnl # The majority of the python scripts are written to be compatible
+dnl # with Python 2.6 and Python 3.4.  Therefore, they may be installed
+dnl # and used with either interpreter.  This option is intended to
+dnl # to provide a method to specify the default system version, and
+dnl # set the PYTHON environment variable accordingly.
+dnl #
+AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_PYTHON], [
+	AC_ARG_WITH([python],
+		AC_HELP_STRING([--with-python[=VERSION]],
+		[default system python version @<:@default=check@:>@]),
+		[with_python=$withval],
+		[with_python=check])
+
+	AS_CASE([$with_python],
+		[check],
+		[AS_IF([test -x /usr/bin/python3],
+			[PYTHON="python3"],
+			[AS_IF([test -x /usr/bin/python2],
+				[PYTHON="python2"],
+				[PYTHON=""]
+			)]
+		)],
+		[2*], [PYTHON="python${with_python}"],
+		[*python2*], [PYTHON="${with_python}"],
+		[3*], [PYTHON="python${with_python}"],
+		[*python3*], [PYTHON="${with_python}"],
+		[no], [PYTHON=""],
+		[AC_MSG_ERROR([Unknown --with-python value '$with_python'])]
+	)
+
+	AS_IF([$PYTHON --version >/dev/null 2>&1], [ /bin/true ], [
+		AC_MSG_ERROR([Cannot find $PYTHON in your system path])
+	])
+
+	AM_PATH_PYTHON([2.6], [], [:])
+	AM_CONDITIONAL([USING_PYTHON], [test "$PYTHON" != :])
+	AM_CONDITIONAL([USING_PYTHON_2], [test "${PYTHON_VERSION:0:2}" = "2."])
+	AM_CONDITIONAL([USING_PYTHON_3], [test "${PYTHON_VERSION:0:2}" = "3."])
+
+	dnl #
+	dnl # Minimum supported Python versions for utilities:
+	dnl # Python 2.6.x, or Python 3.4.x
+	dnl #
+	AS_IF([test "${PYTHON_VERSION:0:2}" = "2."], [
+		ZFS_AC_PYTHON_VERSION([>= '2.6'], [ /bin/true ],
+			[AC_MSG_ERROR("Python >= 2.6.x is not available")])
+	])
+
+	AS_IF([test "${PYTHON_VERSION:0:2}" = "3."], [
+		ZFS_AC_PYTHON_VERSION([>= '3.4'], [ /bin/true ],
+			[AC_MSG_ERROR("Python >= 3.4.x is not available")])
+	])
+
+	dnl #
+	dnl # Request that packages be built for a specific Python version.
+	dnl #
+	AS_IF([test $with_python != check], [
+		PYTHON_PKG_VERSION=`echo ${PYTHON} | tr -d 'a-zA-Z.'`
+		DEFINE_PYTHON_PKG_VERSION='--define "__use_python_pkg_version '${PYTHON_PKG_VERSION}'"'
+		DEFINE_PYTHON_VERSION='--define "__use_python '${PYTHON}'"'
+	], [
+		DEFINE_PYTHON_VERSION=''
+		DEFINE_PYTHON_PKG_VERSION=''
+	])
+
+	AC_SUBST(DEFINE_PYTHON_VERSION)
+	AC_SUBST(DEFINE_PYTHON_PKG_VERSION)
+])

config/always-pyzfs.m4

@@ -1,80 +1,44 @@
 dnl #
-dnl # ZFS_AC_PYTHON_MODULE(module_name, [action-if-true], [action-if-false])
+dnl # Determines if pyzfs can be built, requires Python 2.7 or latter.
 dnl #
-dnl # Checks for Python module. Freely inspired by AX_PYTHON_MODULE
-dnl # https://www.gnu.org/software/autoconf-archive/ax_python_module.html
-dnl #
-AC_DEFUN([ZFS_AC_PYTHON_MODULE],[
-	PYTHON_NAME=`basename $PYTHON`
-	AC_MSG_CHECKING([for $PYTHON_NAME module: $1])
-	$PYTHON -c "import $1" 2>/dev/null
-	if test $? -eq 0;
-	then
-		AC_MSG_RESULT(yes)
-		m4_ifvaln([$2], [$2])
-	else
-		AC_MSG_RESULT(no)
-		m4_ifvaln([$3], [$3])
-	fi
-])
-
-dnl #
-dnl # ZFS_AC_PYTHON_VERSION(version, [action-if-true], [action-if-false])
-dnl #
-dnl # Verify Python version
-dnl #
-AC_DEFUN([ZFS_AC_PYTHON_VERSION], [
-	AC_MSG_CHECKING([for a version of Python $1])
-	version_check=`$PYTHON -c "import sys; print (sys.version.split()[[0]] $1)"`
-	if test "$version_check" = "True";
-	then
-		AC_MSG_RESULT(yes)
-		m4_ifvaln([$2], [$2])
-	else
-		AC_MSG_RESULT(no)
-		m4_ifvaln([$3], [$3])
-	fi
-
-])
-
 AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_PYZFS], [
-	PYTHON_REQUIRED_VERSION="<= '2.7.x'"
-
 	AC_ARG_ENABLE([pyzfs],
 		AC_HELP_STRING([--enable-pyzfs],
 		[install libzfs_core python bindings @<:@default=check@:>@]),
 		[enable_pyzfs=$enableval],
 		[enable_pyzfs=check])
 
-	AM_PATH_PYTHON([2.7], [], [
+	dnl #
+	dnl # Packages for pyzfs specifically enabled/disabled.
+	dnl #
+	AS_IF([test "x$enable_pyzfs" != xcheck], [
 		AS_IF([test "x$enable_pyzfs" = xyes], [
-			AC_MSG_ERROR("python >= 2.7 is not installed")
+			DEFINE_PYZFS='--with pyzfs'
-		], [test ! "x$enable_pyzfs" = xno], [
+		], [
-			enable_pyzfs=no
+			DEFINE_PYZFS='--without pyzfs'
-		])
-	])
-	AM_CONDITIONAL([HAVE_PYTHON], [test "$PYTHON" != :])
-
-	dnl #
-	dnl # Python 2.7.x is supported, other versions (3.5) are not yet
-	dnl #
-	AS_IF([test "x$enable_pyzfs" = xcheck], [
-		ZFS_AC_PYTHON_VERSION([$PYTHON_REQUIRED_VERSION], [], [
-			AS_IF([test "x$enable_pyzfs" = xyes], [
-				AC_MSG_ERROR("Python $PYTHON_REQUIRED_VERSION is not available")
-			], [test ! "x$enable_pyzfs" = xno], [
-				enable_pyzfs=no
-			])
 		])
+	], [
+		DEFINE_PYZFS=''
 	])
+	AC_SUBST(DEFINE_PYZFS)
 
 	dnl #
 	dnl # Require python-devel libraries
 	dnl #
-	AS_IF([test "x$enable_pyzfs" = xcheck], [
+	AS_IF([test "x$enable_pyzfs" = xcheck  -o "x$enable_pyzfs" = xyes], [
+		AS_IF([test "${PYTHON_VERSION:0:2}" = "2."], [
+			PYTHON_REQUIRED_VERSION=">= '2.7.0'"
+		], [
+			AS_IF([test "${PYTHON_VERSION:0:2}" = "3."], [
+				PYTHON_REQUIRED_VERSION=">= '3.4.0'"
+			], [
+				AC_MSG_ERROR("Python $PYTHON_VERSION unknown")
+			])
+		])
+
 		AX_PYTHON_DEVEL([$PYTHON_REQUIRED_VERSION], [
 			AS_IF([test "x$enable_pyzfs" = xyes], [
-				AC_MSG_ERROR("Python development library is not available")
+				AC_MSG_ERROR("Python $PYTHON_REQUIRED_VERSION development library is not installed")
 			], [test ! "x$enable_pyzfs" = xno], [
 				enable_pyzfs=no
 			])
@@ -84,10 +48,10 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_PYZFS], [
 	dnl #
 	dnl # Python "setuptools" module is required to build and install pyzfs
 	dnl #
-	AS_IF([test "x$enable_pyzfs" = xcheck], [
+	AS_IF([test "x$enable_pyzfs" = xcheck -o "x$enable_pyzfs" = xyes], [
 		ZFS_AC_PYTHON_MODULE([setuptools], [], [
 			AS_IF([test "x$enable_pyzfs" = xyes], [
-				AC_MSG_ERROR("python-setuptools is not installed")
+				AC_MSG_ERROR("Python $PYTHON_VERSION setuptools is not installed")
 			], [test ! "x$enable_pyzfs" = xno], [
 				enable_pyzfs=no
 			])
@@ -97,10 +61,10 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_PYZFS], [
 	dnl #
 	dnl # Python "cffi" module is required to run pyzfs
 	dnl #
-	AS_IF([test "x$enable_pyzfs" = xcheck], [
+	AS_IF([test "x$enable_pyzfs" = xcheck -o "x$enable_pyzfs" = xyes], [
 		ZFS_AC_PYTHON_MODULE([cffi], [], [
 			AS_IF([test "x$enable_pyzfs" = xyes], [
-				AC_MSG_ERROR("python-cffi is not installed")
+				AC_MSG_ERROR("Python $PYTHON_VERSION cffi is not installed")
 			], [test ! "x$enable_pyzfs" = xno], [
 				enable_pyzfs=no
 			])
@@ -114,12 +78,8 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS_PYZFS], [
 
 	AM_CONDITIONAL([PYZFS_ENABLED], [test x$enable_pyzfs = xyes])
 	AC_SUBST([PYZFS_ENABLED], [$enable_pyzfs])
-
-	AS_IF([test "x$enable_pyzfs" = xyes], [
-		DEFINE_PYZFS='--define "_pyzfs 1"'
-	],[
-		DEFINE_PYZFS=''
-	])
-	AC_SUBST(DEFINE_PYZFS)
 	AC_SUBST(pythonsitedir, [$PYTHON_SITE_PKG])
+
+	AC_MSG_CHECKING([whether to enable pyzfs: ])
+	AC_MSG_RESULT($enable_pyzfs)
 ])

config/deb.am

@@ -47,7 +47,7 @@ deb-utils: deb-local rpm-utils
 	pkg7=$${name}-test-$${version}.$${arch}.rpm; \
 	pkg8=$${name}-dracut-$${version}.$${arch}.rpm; \
 	pkg9=$${name}-initramfs-$${version}.$${arch}.rpm; \
-	pkg10=pyzfs-$${version}.noarch.rpm; \
+	pkg10=`ls python*-pyzfs-$${version}* | tail -1`; \
 ## Arguments need to be passed to dh_shlibdeps. Alien provides no mechanism
 ## to do this, so we install a shim onto the path which calls the real
 ## dh_shlibdeps with the required arguments.

config/zfs-build.m4

@@ -160,6 +160,7 @@ AC_DEFUN([ZFS_AC_CONFIG_ALWAYS], [
 	ZFS_AC_CONFIG_ALWAYS_CC_ASAN
 	ZFS_AC_CONFIG_ALWAYS_TOOLCHAIN_SIMD
 	ZFS_AC_CONFIG_ALWAYS_ARCH
+	ZFS_AC_CONFIG_ALWAYS_PYTHON
 	ZFS_AC_CONFIG_ALWAYS_PYZFS
 ])
 
@@ -264,10 +265,13 @@ AC_DEFUN([ZFS_AC_RPM], [
 	RPM_DEFINE_UTIL+=' $(DEFINE_INITRAMFS)'
 	RPM_DEFINE_UTIL+=' $(DEFINE_SYSTEMD)'
 	RPM_DEFINE_UTIL+=' $(DEFINE_PYZFS)'
+	RPM_DEFINE_UTIL+=' $(DEFINE_PYTHON_VERSION)'
+	RPM_DEFINE_UTIL+=' $(DEFINE_PYTHON_PKG_VERSION)'
 
-	dnl # Override default lib directory on Debian/Ubuntu systems.  The provided
+	dnl # Override default lib directory on Debian/Ubuntu systems.  The
-	dnl # /usr/lib/rpm/platform/<arch>/macros files do not specify the correct
+	dnl # provided /usr/lib/rpm/platform/<arch>/macros files do not
-	dnl # path for multiarch systems as described by the packaging guidelines.
+	dnl # specify the correct path for multiarch systems as described
+	dnl # by the packaging guidelines.
 	dnl #
 	dnl # https://wiki.ubuntu.com/MultiarchSpec
 	dnl # https://wiki.debian.org/Multiarch/Implementation

contrib/pyzfs/Makefile.am

@@ -27,7 +27,7 @@ install-exec-local:
 	$(PYTHON) $(srcdir)/setup.py install \
 	--prefix $(prefix) \
 	--root $(DESTDIR)/ \
-	--install-lib $(pythondir) \
+	--install-lib $(pythonsitedir) \
 	--single-version-externally-managed \
 	--verbose
 

contrib/pyzfs/setup.py

@@ -29,8 +29,13 @@ setup(
         "Development Status :: 4 - Beta",
         "Intended Audience :: Developers",
         "License :: OSI Approved :: Apache Software License",
-        "Programming Language :: Python :: 2 :: Only",
+        "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 2.7",
+        "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.4",
+        "Programming Language :: Python :: 3.5",
+        "Programming Language :: Python :: 3.6",
+        "Programming Language :: Python :: 3.7",
         "Topic :: System :: Filesystems",
         "Topic :: Software Development :: Libraries",
     ],
@@ -48,7 +53,7 @@ setup(
     setup_requires=[
         "cffi",
     ],
-    python_requires='>=2.7,<3',
+    python_requires='>=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*,<4',
     zip_safe=False,
     test_suite="libzfs_core.test",
 )

rpm/generic/zfs.spec.in

@@ -53,16 +53,6 @@
 %bcond_with    asan
 %bcond_with    systemd
 
-# Python permits the !/usr/bin/python shebang for scripts that are cross
-# compatible between python2 and python3, but Fedora 28 does not.  Fedora
-# wants us to choose python3 for cross-compatible scripts.  Since we want
-# to support python2 and python3 users, exclude our scripts from Fedora 28's
-# RPM build check, so that we don't get a bunch of build warnings.
-#
-# Details: https://github.com/zfsonlinux/zfs/issues/7360
-#
-%global __brp_mangle_shebangs_exclude_from arc_summary.py|arcstat.py|dbufstat.py|test-runner.py|zts-report.py
-
 # Generic enable switch for systemd
 %if %{with systemd}
 %define _systemd 1
@@ -85,6 +75,32 @@
 %define _systemd 1
 %endif
 
+# When not specified default to distribution provided version.  This
+# is normally Python 3, but for RHEL <= 7 only Python 2 is provided.
+%if %{undefined __use_python}
+%if 0%{?rhel} && 0%{?rhel} <= 7
+%define __python              /usr/bin/python2
+%define __python_pkg_version  2
+%define __python_cffi_pkg     python-cffi
+%else
+%define __python              /usr/bin/python3
+%define __python_pkg_version  3
+%define __python_cffi_pkg     python3-cffi
+%endif
+%else
+%define __python              %{__use_python}
+%define __python_pkg_version  %{__use_python_pkg_version}
+%define __python_cffi_pkg     python%{__python_pkg_version}-cffi
+%endif
+
+# By default python-pyzfs is enabled, with the exception of
+# RHEL 6 which by default uses Python 2.6 which is too old.
+%if 0%{?rhel} == 6
+%bcond_with    pyzfs
+%else
+%bcond_without pyzfs
+%endif
+
 Name:           @PACKAGE@
 Version:        @VERSION@
 Release:        @RELEASE@%{?dist}
@@ -135,7 +151,7 @@ Requires:  util-linux
 Requires:  sysstat
 
 %description
-This package contains the ZFS command line utilities.
+This package contains the core ZFS command line utilities.
 
 %package -n libzpool2
 Summary:        Native ZFS pool library for Linux
@@ -219,6 +235,7 @@ Requires:       acl
 Requires:       sudo
 Requires:       sysstat
 Requires:       libaio
+Requires:       python%{__python_pkg_version}
 %if 0%{?rhel}%{?fedora}%{?suse_version}
 BuildRequires:  libaio-devel
 %endif
@@ -240,23 +257,23 @@ Requires:       grep
 This package contains a dracut module used to construct an initramfs
 image which is ZFS aware.
 
-%if 0%{?_pyzfs}
+%if %{with pyzfs}
-%package -n pyzfs
+%package -n python%{__python_pkg_version}-pyzfs
-Summary:        Python wrapper for libzfs_core
+Summary:        Python %{python_version} wrapper for libzfs_core
 Group:          Development/Languages/Python
 License:        Apache-2.0
 BuildArch:      noarch
 Requires:       libzfs2 = %{version}
 Requires:       libnvpair1 = %{version}
 Requires:       libffi
-Requires:       python >= 2.7
+Requires:       python%{__python_pkg_version}
-Requires:       python-cffi
+Requires:       %{__python_cffi_pkg}
 %if 0%{?rhel}%{?fedora}%{?suse_version}
-BuildRequires:  python-devel
+BuildRequires:  python%{__python_pkg_version}-devel
 BuildRequires:  libffi-devel
 %endif
 
-%description -n pyzfs
+%description -n python%{__python_pkg_version}-pyzfs
 This package provides a python wrapper for the libzfs_core C library.
 %endif
 
@@ -299,6 +316,12 @@ image which is ZFS aware.
     %define systemd --enable-sysvinit --disable-systemd
 %endif
 
+%if %{with pyzfs}
+    %define pyzfs --enable-pyzfs
+%else
+    %define pyzfs --disable-pyzfs
+%endif
+
 %setup -q
 
 %build
@@ -307,11 +330,13 @@ image which is ZFS aware.
     --with-udevdir=%{_udevdir} \
     --with-udevruledir=%{_udevruledir} \
     --with-dracutdir=%{_dracutdir} \
+    --with-python=%{__python} \
     --disable-static \
     %{debug} \
     %{debuginfo} \
     %{asan} \
-    %{systemd}
+    %{systemd}\
+    %{pyzfs}
 make %{?_smp_mflags}
 
 %install
@@ -379,12 +404,20 @@ systemctl --system daemon-reload >/dev/null || true
 %endif
 
 %files
+# Core utilities
 %{_sbindir}/*
-%{_bindir}/*
+%{_bindir}/raidz_test
-%{_libexecdir}/%{name}
+%{_bindir}/zgenhostid
+# Optional Python 2/3 scripts
+%{_bindir}/arc_summary
+%{_bindir}/arcstat
+%{_bindir}/dbufstat
+# Man pages
 %{_mandir}/man1/*
 %{_mandir}/man5/*
 %{_mandir}/man8/*
+# Configuration files and scripts
+%{_libexecdir}/%{name}
 %{_udevdir}/vdev_id
 %{_udevdir}/zvol_id
 %{_udevdir}/rules.d/*
@@ -426,8 +459,8 @@ systemctl --system daemon-reload >/dev/null || true
 %doc contrib/dracut/README.dracut.markdown
 %{_dracutdir}/modules.d/*
 
-%if 0%{?_pyzfs}
+%if %{with pyzfs}
-%files -n pyzfs
+%files -n python%{__python_pkg_version}-pyzfs
 %doc contrib/pyzfs/README
 %doc contrib/pyzfs/LICENSE
 %defattr(-,root,root,-)

tests/test-runner/bin/Makefile.am

@@ -2,3 +2,14 @@ pkgdatadir = $(datadir)/@PACKAGE@/test-runner/bin
 dist_pkgdata_SCRIPTS = \
 	test-runner.py \
 	zts-report.py
+#
+# These scripts are compatibile with both Python 2.6 and 3.4.  As such the
+# python 3 shebang can be replaced at install time when targeting a python
+# 2 system.  This allows us to maintain a single version of the source.
+#
+if USING_PYTHON_2
+install-data-hook:
+	sed --in-place 's|^#!/usr/bin/python3|#!/usr/bin/python2|' \
+	    $(DESTDIR)$(pkgdatadir)/test-runner.py \
+	    $(DESTDIR)$(pkgdatadir)/zts-report.py
+endif

tests/test-runner/bin/test-runner.py

@@ -15,6 +15,8 @@
 # Copyright (c) 2012, 2015 by Delphix. All rights reserved.
 # Copyright (c) 2017 Datto Inc.
 #
+# This script must remain compatible with Python 2.6+ and Python 3.4+.
+#
 
 # some python 2.7 system don't have a configparser shim
 try:

tests/test-runner/bin/zts-report.py

@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python3
 
 #
 # This file and its contents are supplied under the terms of the
@@ -15,6 +15,8 @@
 # Copyright (c) 2017 by Delphix. All rights reserved.
 # Copyright (c) 2018 by Lawrence Livermore National Security, LLC.
 #
+# This script must remain compatible with Python 2.6+ and Python 3.4+.
+#
 
 import os
 import re

tests/zfs-tests/include/commands.cfg

@@ -146,10 +146,10 @@ export ZFS_FILES='zdb
     zpool
     ztest
     raidz_test
-    arc_summary.py
+    arc_summary
-    arc_summary3.py
+    arc_summary3
-    arcstat.py
+    arcstat
-    dbufstat.py
+    dbufstat
     zed
     zgenhostid
     zstreamdump'

tests/zfs-tests/tests/functional/arc/dbufstats_001_pos.ksh

@@ -37,7 +37,7 @@
 # 2. Store output from dbufs kstat
 # 3. Store output from dbufstats kstat
 # 4. Compare stats presented in dbufstats with stat generated using
-#    dbufstat.py and the dbufs kstat output
+#    dbufstat and the dbufs kstat output
 #
 
 DBUFSTATS_FILE=$(mktemp $TEST_BASE_DIR/dbufstats.out.XXXXXX)
@@ -56,7 +56,7 @@ function testdbufstat # stat_name dbufstat_filter
         [[ -n "$2" ]] && filter="-F $2"
 
 	from_dbufstat=$(grep -w "$name" "$DBUFSTATS_FILE" | awk '{ print $3 }')
-	from_dbufs=$(dbufstat.py -bxn -i "$DBUFS_FILE" "$filter" | wc -l)
+	from_dbufs=$(dbufstat -bxn -i "$DBUFS_FILE" "$filter" | wc -l)
 
 	within_tolerance $from_dbufstat $from_dbufs 9 \
 	    || log_fail "Stat $name exceeded tolerance"

tests/zfs-tests/tests/functional/arc/dbufstats_002_pos.ksh

@@ -62,18 +62,18 @@ objid=$(stat --format="%i" "$TESTDIR/file")
 log_note "Object ID for $TESTDIR/file is $objid"
 
 log_must eval "cat /proc/spl/kstat/zfs/dbufs > $DBUFS_FILE"
-dbuf=$(dbufstat.py -bxn -i "$DBUFS_FILE" -F "object=$objid" | wc -l)
+dbuf=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid" | wc -l)
-mru=$(dbufstat.py -bxn -i "$DBUFS_FILE" -F "object=$objid,list=1" | wc -l)
+mru=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid,list=1" | wc -l)
-mfu=$(dbufstat.py -bxn -i "$DBUFS_FILE" -F "object=$objid,list=3" | wc -l)
+mfu=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid,list=3" | wc -l)
 log_note "dbuf count is $dbuf, mru count is $mru, mfu count is $mfu"
 verify_ne "0" "$mru" "mru count"
 verify_eq "0" "$mfu" "mfu count"
 
 log_must eval "cat $TESTDIR/file > /dev/null"
 log_must eval "cat /proc/spl/kstat/zfs/dbufs > $DBUFS_FILE"
-dbuf=$(dbufstat.py -bxn -i "$DBUFS_FILE" -F "object=$objid" | wc -l)
+dbuf=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid" | wc -l)
-mru=$(dbufstat.py -bxn -i "$DBUFS_FILE" -F "object=$objid,list=1" | wc -l)
+mru=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid,list=1" | wc -l)
-mfu=$(dbufstat.py -bxn -i "$DBUFS_FILE" -F "object=$objid,list=3" | wc -l)
+mfu=$(dbufstat -bxn -i "$DBUFS_FILE" -F "object=$objid,list=3" | wc -l)
 log_note "dbuf count is $dbuf, mru count is $mru, mfu count is $mfu"
 verify_ne "0" "$mfu" "mfu count"
 

tests/zfs-tests/tests/functional/cli_user/misc/arc_summary3_001_pos.ksh

@@ -45,12 +45,12 @@ fi
 
 
 set -A args  "" "-a" "-d" "-p 1" "-g" "-s arc" "-r"
-log_assert "arc_summary3.py generates output and doesn't return an error code"
+log_assert "arc_summary3 generates output and doesn't return an error code"
 
 typeset -i i=0
 while [[ $i -lt ${#args[*]} ]]; do
-        log_must eval "arc_summary3.py ${args[i]} > /dev/null"
+        log_must eval "arc_summary3 ${args[i]} > /dev/null"
         ((i = i + 1))
 done
 
-log_pass "arc_summary3.py generates output and doesn't return an error code"
+log_pass "arc_summary3 generates output and doesn't return an error code"

tests/zfs-tests/tests/functional/cli_user/misc/arc_summary_001_pos.ksh

@@ -29,15 +29,15 @@
 
 set -A args  "" "-a" "-d" "-p 1"
 
-log_assert "arc_summary.py generates output and doesn't return an error code"
+log_assert "arc_summary generates output and doesn't return an error code"
 
 typeset -i i=0
 while [[ $i -lt ${#args[*]} ]]; do
-        log_must eval "arc_summary.py ${args[i]} > /dev/null"
+        log_must eval "arc_summary ${args[i]} > /dev/null"
         ((i = i + 1))
 done
 
-log_must eval "arc_summary.py | head > /dev/null"
+log_must eval "arc_summary | head > /dev/null"
-log_must eval "arc_summary.py | head -1 > /dev/null"
+log_must eval "arc_summary | head -1 > /dev/null"
 
-log_pass "arc_summary.py generates output and doesn't return an error code"
+log_pass "arc_summary generates output and doesn't return an error code"

tests/zfs-tests/tests/functional/cli_user/misc/arc_summary_002_neg.ksh

@@ -29,10 +29,10 @@
 
 typeset args=("-x" "-r" "-5" "-p 7" "--err" "-@")
 
-log_assert "arc_summary.py generates an error code with invalid options"
+log_assert "arc_summary generates an error code with invalid options"
 
 for arg in "${args[@]}"; do
-        log_mustnot eval "arc_summary.py $arg > /dev/null"
+        log_mustnot eval "arc_summary $arg > /dev/null"
 done
 
-log_pass "arc_summary.py generates an error code with invalid options"
+log_pass "arc_summary generates an error code with invalid options"

tests/zfs-tests/tests/functional/cli_user/misc/arcstat_001_pos.ksh

@@ -30,12 +30,12 @@
 set -A args  "" "-s \",\"" "-x" "-v" \
     "-f time,hit%,dh%,ph%,mh%"
 
-log_assert "arcstat.py generates output and doesn't return an error code"
+log_assert "arcstat generates output and doesn't return an error code"
 
 typeset -i i=0
 while [[ $i -lt ${#args[*]} ]]; do
-        log_must eval "arcstat.py ${args[i]} > /dev/null"
+        log_must eval "arcstat ${args[i]} > /dev/null"
         ((i = i + 1))
 done
-log_pass "arcstat.py generates output and doesn't return an error code"
+log_pass "arcstat generates output and doesn't return an error code"
 

tests/zfs-tests/tests/functional/cli_user/misc/dbufstat_001_pos.ksh

@@ -29,15 +29,15 @@
 
 set -A args  "" "-b" "-d" "-r" "-v" "-s \",\"" "-x" "-n"
 
-log_assert "dbufstat.py generates output and doesn't return an error code"
+log_assert "dbufstat generates output and doesn't return an error code"
 
 typeset -i i=0
 while [[ $i -lt ${#args[*]} ]]; do
-        log_must eval "dbufstat.py ${args[i]} > /dev/null"
+        log_must eval "dbufstat ${args[i]} > /dev/null"
         ((i = i + 1))
 done
 
-# A simple test of dbufstat.py filter functionality
+# A simple test of dbufstat filter functionality
-log_must eval "dbufstat.py -F object=10,dbc=1,pool=$TESTPOOL > /dev/null"
+log_must eval "dbufstat -F object=10,dbc=1,pool=$TESTPOOL > /dev/null"
 
-log_pass "dbufstat.py generates output and doesn't return an error code"
+log_pass "dbufstat generates output and doesn't return an error code"

tests/zfs-tests/tests/functional/pyzfs/.gitignore

@@ -0,0 +1 @@
+pyzfs_unittest.ksh

tests/zfs-tests/tests/functional/pyzfs/Makefile.am

@@ -1,4 +1,18 @@
-pkgdatadir = $(datadir)/@PACKAGE@/zfs-tests/tests/functional/pyzfs
+pkgpyzfsdir = $(datadir)/@PACKAGE@/zfs-tests/tests/functional/pyzfs
-
+pkgpyzfs_SCRIPTS = \
-dist_pkgdata_SCRIPTS = \
 	pyzfs_unittest.ksh
+
+EXTRA_DIST = \
+	pyzfs_unittest.ksh.in
+
+#
+# The pyzfs module is built either for Python 2 or Python 3.  In order
+# to properly test it the unit tests must be updated to the matching vesion.
+#
+$(pkgpyzfs_SCRIPTS):%:%.in
+	-$(SED) -e 's,@PYTHON\@,$(PYTHON),g' \
+		$< >'$@'
+	-chmod 775 $@
+
+distclean-local::
+	-$(RM) $(pkgpyzfs_SCRIPTS)

tests/zfs-tests/tests/functional/pyzfs/pyzfs_unittest.ksh.in

@@ -28,7 +28,7 @@
 verify_runnable "global"
 
 # Verify that the required dependencies for testing are installed.
-python -c "import cffi" 2>/dev/null
+@PYTHON@ -c "import cffi" 2>/dev/null
 if [ $? -eq 1 ]; then
 	log_unsupported "python-cffi not found by Python"
 fi
@@ -37,7 +37,7 @@ fi
 # only if pyzfs was not installed due to missing, build-time, dependencies; if
 # we cannot load "libzfs_core" due to other reasons, for instance an API/ABI
 # mismatch, we want to report it.
-python -c '
+@PYTHON@ -c '
 import pkgutil, sys
 sys.exit(pkgutil.find_loader("libzfs_core") is None)'
 if [ $? -eq 1 ]; then
@@ -47,7 +47,7 @@ fi
 log_assert "Verify the nvlist and libzfs_core Python unittest run successfully"
 
 # NOTE: don't use log_must() here because it makes output unreadable
-python -m unittest --verbose \
+@PYTHON@ -m unittest --verbose \
 	libzfs_core.test.test_nvlist.TestNVList \
 	libzfs_core.test.test_libzfs_core.ZFSTest
 if [ $? -ne 0 ]; then