build: python 3 compatibility

Ubuntu 16.04 "xenial xerus" does not come with Python 2.x by default.
It is possible to install a python-2.7 package, but this has its own
problem: no `python` or `python2` symlink (see #7717).

This fixes the following scripts to work with python 3:
- `make check` (bctest,py, bitcoin-util-test.py)
- `make translate` (extract_strings_qt.py)
- `make symbols-check` (symbol-check.py)
- `make security-check` (security-check.py)

Explicitly call the python commands using $(PYTHON) instead
of relying on the interpreter line at the top of the scripts.

2 files changed, 49 insertions, 48 deletions

diff --git a/contrib/devtools/security-check.py b/contrib/devtools/security-check.py
index 0319f739c4..301fea85c1 100755
--- a/contrib/devtools/security-check.py
+++ b/contrib/devtools/security-check.py
@@ -5,7 +5,7 @@ Exit status will be 0 if successful, and the program will be silent.
 Otherwise the exit status will be 1 and it will log which executables failed which checks.
 Needs `readelf` (for ELF) and `objdump` (for PE).
 '''
-from __future__ import division,print_function
+from __future__ import division,print_function,unicode_literals
 import subprocess
 import sys
 import os
@@ -23,9 +23,9 @@ def check_ELF_PIE(executable):
         raise IOError('Error opening file')
 
     ok = False
-    for line in stdout.split('\n'):
+    for line in stdout.split(b'\n'):
         line = line.split()
-        if len(line)>=2 and line[0] == 'Type:' and line[1] == 'DYN':
+        if len(line)>=2 and line[0] == b'Type:' and line[1] == b'DYN':
             ok = True
     return ok
 
@@ -38,17 +38,17 @@ def get_ELF_program_headers(executable):
     in_headers = False
     count = 0
     headers = []
-    for line in stdout.split('\n'):
-        if line.startswith('Program Headers:'):
+    for line in stdout.split(b'\n'):
+        if line.startswith(b'Program Headers:'):
             in_headers = True
-        if line == '':
+        if line == b'':
             in_headers = False
         if in_headers:
             if count == 1: # header line
-                ofs_typ = line.find('Type')
-                ofs_offset = line.find('Offset')
-                ofs_flags = line.find('Flg')
-                ofs_align = line.find('Align')
+                ofs_typ = line.find(b'Type')
+                ofs_offset = line.find(b'Offset')
+                ofs_flags = line.find(b'Flg')
+                ofs_align = line.find(b'Align')
                 if ofs_typ == -1 or ofs_offset == -1 or ofs_flags == -1 or ofs_align  == -1:
                     raise ValueError('Cannot parse elfread -lW output')
             elif count > 1:
@@ -65,9 +65,9 @@ def check_ELF_NX(executable):
     have_wx = False
     have_gnu_stack = False
     for (typ, flags) in get_ELF_program_headers(executable):
-        if typ == 'GNU_STACK':
+        if typ == b'GNU_STACK':
             have_gnu_stack = True
-        if 'W' in flags and 'E' in flags: # section is both writable and executable
+        if b'W' in flags and b'E' in flags: # section is both writable and executable
             have_wx = True
     return have_gnu_stack and not have_wx
 
@@ -84,7 +84,7 @@ def check_ELF_RELRO(executable):
         # However, the dynamic linker need to write to this area so these are RW.
         # Glibc itself takes care of mprotecting this area R after relocations are finished.
         # See also http://permalink.gmane.org/gmane.comp.gnu.binutils/71347
-        if typ == 'GNU_RELRO':
+        if typ == b'GNU_RELRO':
             have_gnu_relro = True
 
     have_bindnow = False
@@ -92,9 +92,9 @@ def check_ELF_RELRO(executable):
     (stdout, stderr) = p.communicate()
     if p.returncode:
         raise IOError('Error opening file')
-    for line in stdout.split('\n'):
+    for line in stdout.split(b'\n'):
         tokens = line.split()
-        if len(tokens)>1 and tokens[1] == '(BIND_NOW)' or (len(tokens)>2 and tokens[1] == '(FLAGS)' and 'BIND_NOW' in tokens[2]):
+        if len(tokens)>1 and tokens[1] == b'(BIND_NOW)' or (len(tokens)>2 and tokens[1] == b'(FLAGS)' and b'BIND_NOW' in tokens[2]):
             have_bindnow = True
     return have_gnu_relro and have_bindnow
 
@@ -107,8 +107,8 @@ def check_ELF_Canary(executable):
     if p.returncode:
         raise IOError('Error opening file')
     ok = False
-    for line in stdout.split('\n'):
-        if '__stack_chk_fail' in line:
+    for line in stdout.split(b'\n'):
+        if b'__stack_chk_fail' in line:
             ok = True
     return ok
 
diff --git a/contrib/devtools/symbol-check.py b/contrib/devtools/symbol-check.py
index 4ad5136f79..e26c0fbb94 100755
--- a/contrib/devtools/symbol-check.py
+++ b/contrib/devtools/symbol-check.py
@@ -11,7 +11,7 @@ Example usage:
 
     find ../gitian-builder/build -type f -executable | xargs python contrib/devtools/symbol-check.py
 '''
-from __future__ import division, print_function
+from __future__ import division, print_function, unicode_literals
 import subprocess
 import re
 import sys
@@ -47,28 +47,28 @@ MAX_VERSIONS = {
 
 # Ignore symbols that are exported as part of every executable
 IGNORE_EXPORTS = {
-'_edata', '_end', '_init', '__bss_start', '_fini', '_IO_stdin_used'
+b'_edata', b'_end', b'_init', b'__bss_start', b'_fini', b'_IO_stdin_used'
 }
 READELF_CMD = os.getenv('READELF', '/usr/bin/readelf')
 CPPFILT_CMD = os.getenv('CPPFILT', '/usr/bin/c++filt')
 # Allowed NEEDED libraries
 ALLOWED_LIBRARIES = {
 # bitcoind and bitcoin-qt
-'libgcc_s.so.1', # GCC base support
-'libc.so.6', # C library
-'libpthread.so.0', # threading
-'libanl.so.1', # DNS resolve
-'libm.so.6', # math library
-'librt.so.1', # real-time (clock)
-'ld-linux-x86-64.so.2', # 64-bit dynamic linker
-'ld-linux.so.2', # 32-bit dynamic linker
+b'libgcc_s.so.1', # GCC base support
+b'libc.so.6', # C library
+b'libpthread.so.0', # threading
+b'libanl.so.1', # DNS resolve
+b'libm.so.6', # math library
+b'librt.so.1', # real-time (clock)
+b'ld-linux-x86-64.so.2', # 64-bit dynamic linker
+b'ld-linux.so.2', # 32-bit dynamic linker
 # bitcoin-qt only
-'libX11-xcb.so.1', # part of X11
-'libX11.so.6', # part of X11
-'libxcb.so.1', # part of X11
-'libfontconfig.so.1', # font support
-'libfreetype.so.6', # font parsing
-'libdl.so.2' # programming interface to dynamic linker
+b'libX11-xcb.so.1', # part of X11
+b'libX11.so.6', # part of X11
+b'libxcb.so.1', # part of X11
+b'libfontconfig.so.1', # font support
+b'libfreetype.so.6', # font parsing
+b'libdl.so.2' # programming interface to dynamic linker
 }
 
 class CPPFilt(object):
@@ -81,7 +81,8 @@ class CPPFilt(object):
         self.proc = subprocess.Popen(CPPFILT_CMD, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
 
     def __call__(self, mangled):
-        self.proc.stdin.write(mangled + '\n')
+        self.proc.stdin.write(mangled + b'\n')
+        self.proc.stdin.flush()
         return self.proc.stdout.readline().rstrip()
 
     def close(self):
@@ -99,24 +100,24 @@ def read_symbols(executable, imports=True):
     if p.returncode:
         raise IOError('Could not read symbols for %s: %s' % (executable, stderr.strip()))
     syms = []
-    for line in stdout.split('\n'):
+    for line in stdout.split(b'\n'):
         line = line.split()
-        if len(line)>7 and re.match('[0-9]+:$', line[0]):
-            (sym, _, version) = line[7].partition('@')
-            is_import = line[6] == 'UND'
-            if version.startswith('@'):
+        if len(line)>7 and re.match(b'[0-9]+:$', line[0]):
+            (sym, _, version) = line[7].partition(b'@')
+            is_import = line[6] == b'UND'
+            if version.startswith(b'@'):
                 version = version[1:]
             if is_import == imports:
                 syms.append((sym, version))
     return syms
 
 def check_version(max_versions, version):
-    if '_' in version:
-        (lib, _, ver) = version.rpartition('_')
+    if b'_' in version:
+        (lib, _, ver) = version.rpartition(b'_')
     else:
         lib = version
         ver = '0'
-    ver = tuple([int(x) for x in ver.split('.')])
+    ver = tuple([int(x) for x in ver.split(b'.')])
     if not lib in max_versions:
         return False
     return ver <= max_versions[lib]
@@ -127,10 +128,10 @@ def read_libraries(filename):
     if p.returncode:
         raise IOError('Error opening file')
     libraries = []
-    for line in stdout.split('\n'):
+    for line in stdout.split(b'\n'):
         tokens = line.split()
-        if len(tokens)>2 and tokens[1] == '(NEEDED)':
-            match = re.match('^Shared library: \[(.*)\]$', ' '.join(tokens[2:]))
+        if len(tokens)>2 and tokens[1] == b'(NEEDED)':
+            match = re.match(b'^Shared library: \[(.*)\]$', b' '.join(tokens[2:]))
             if match:
                 libraries.append(match.group(1))
             else:
@@ -144,18 +145,18 @@ if __name__ == '__main__':
         # Check imported symbols
         for sym,version in read_symbols(filename, True):
             if version and not check_version(MAX_VERSIONS, version):
-                print('%s: symbol %s from unsupported version %s' % (filename, cppfilt(sym), version))
+                print('%s: symbol %s from unsupported version %s' % (filename, cppfilt(sym).decode('utf-8'), version.decode('utf-8')))
                 retval = 1
         # Check exported symbols
         for sym,version in read_symbols(filename, False):
             if sym in IGNORE_EXPORTS:
                 continue
-            print('%s: export of symbol %s not allowed' % (filename, cppfilt(sym)))
+            print('%s: export of symbol %s not allowed' % (filename, cppfilt(sym).decode('utf-8')))
             retval = 1
         # Check dependency libraries
         for library_name in read_libraries(filename):
             if library_name not in ALLOWED_LIBRARIES:
-                print('%s: NEEDED library %s is not allowed' % (filename, library_name))
+                print('%s: NEEDED library %s is not allowed' % (filename, library_name.decode('utf-8')))
                 retval = 1
 
     exit(retval)