New depends module to check dependencies. Moved version check to new depends module.

src/bitmessagemain.py

@@ -9,25 +9,8 @@
 
 # The software version variable is now held in shared.py
 
-
+import depends
-import sys
+depends.check_dependencies()
-#Version check
-#Older versions of Python don't support the print function while Python 3 doesn't
-#like the print statement, so we use sys.stdout for the version check. After this
-#check we can then use the print function in the remainder of this file. Currently
-#in order to use logging, a lot of unnecessary code needs to be executed which could
-#potentially render this version check useless. So logging won't be used here until
-#there is a more efficient way to configure logging
-if sys.hexversion >= 0x3000000:
-    msg = "PyBitmessage does not support Python 3. Python 2.7.3 or later is required. Your version: %s" % sys.version
-    #logger.critical(msg)
-    sys.stdout.write(msg)
-    sys.exit(0)
-if sys.hexversion < 0x20703F0:
-    msg = "You should use Python 2.7.3 or greater (but not Python 3). Your version: %s" % sys.version
-    #logger.critical(msg)
-    sys.stdout.write(msg)
-    sys.exit(0)
 
 import signal  # Used to capture a Ctrl-C keypress so that Bitmessage can shutdown gracefully.
 # The next 3 are used for the API
@@ -36,6 +19,7 @@ import os
 import socket
 import ctypes
 from struct import pack
+import sys
 
 from SimpleXMLRPCServer import SimpleXMLRPCServer
 from api import MySimpleXMLRPCRequestHandler
@@ -227,17 +211,15 @@ class Main:
 
         if daemon == False and shared.safeConfigGetBoolean('bitmessagesettings', 'daemon') == False:
             if curses == False:
-                try:
+                if not depends.check_pyqt():
-                    from PyQt4 import QtCore, QtGui
-                except Exception as err:
                     print('PyBitmessage requires PyQt unless you want to run it as a daemon and interact with it using the API. You can download PyQt from http://www.riverbankcomputing.com/software/pyqt/download   or by searching Google for \'PyQt Download\'. If you want to run in daemon mode, see https://bitmessage.org/wiki/Daemon')
-                    print('Error message:', err)
                     print('You can also run PyBitmessage with the new curses interface by providing \'-c\' as a commandline argument.')
-                    os._exit(0)
+                    sys.exit()
 
                 import bitmessageqt
                 bitmessageqt.run()
             else:
+                if depends.check_curses():
                     print('Running with curses')
                     import bitmessagecurses
                     bitmessagecurses.runwrapper()

src/depends.py

@@ -0,0 +1,219 @@
+#! python
+
+import sys
+
+#Only really old versions of Python don't have sys.hexversion. We don't support
+#them. The logging module was introduced in Python 2.3
+if not hasattr(sys, 'hexversion') or sys.hexversion < 0x20300F0:
+    sys.stdout.write('Python version: ' + sys.version)
+    sys.stdout.write('PyBitmessage requires Python 2.7.5 or greater (but not Python 3)')
+    sys.exit()
+
+#We can now use logging so set up a simple configuration
+import logging
+formatter = logging.Formatter(
+    '%(levelname)s: %(message)s'
+)
+handler = logging.StreamHandler(sys.stdout)
+handler.setFormatter(formatter)
+logger = logging.getLogger(__name__)
+logger.addHandler(handler)
+logger.setLevel(logging.ERROR)
+
+#We need to check hashlib for RIPEMD-160, as it won't be available if OpenSSL is
+#not linked against or the linked OpenSSL has RIPEMD disabled.
+def check_hashlib():
+    if sys.hexversion < 0x020500F0:
+        logger.error('The hashlib module is not included in this version of Python.')
+        return False
+    import hashlib
+    if '_hashlib' not in hashlib.__dict__:
+        logger.error('The RIPEMD-160 hash algorithm is not available. The hashlib module is not linked against OpenSSL.')
+        return False
+    try:
+        hashlib.new('ripemd160')
+    except ValueError:
+        logger.error('The RIPEMD-160 hash algorithm is not available. The hashlib module utilizes an OpenSSL library with RIPEMD disabled.')
+        return False
+    return True
+
+def check_sqlite():
+    if sys.hexversion < 0x020500F0:
+        logger.error('The sqlite3 module is not included in this version of Python.')
+        return False
+    try:
+        import sqlite3
+    except ImportError:
+        logger.error('The sqlite3 module is not available')
+        return False
+
+    logger.info('sqlite3 Module Version: ' + sqlite3.version)
+    logger.info('SQLite Library Version: ' + sqlite3.sqlite_version)
+    #sqlite_version_number formula: https://sqlite.org/c3ref/c_source_id.html
+    sqlite_version_number = sqlite3.sqlite_version_info[0] * 1000000 + sqlite3.sqlite_version_info[1] * 1000 + sqlite3.sqlite_version_info[2]
+
+    conn = None
+    try:
+        try:
+            conn = sqlite3.connect(':memory:')
+            if sqlite_version_number >= 3006018:
+                sqlite_source_id = conn.execute('SELECT sqlite_source_id();').fetchone()[0]
+                logger.info('SQLite Library Source ID: ' + sqlite_source_id)
+            if sqlite_version_number >= 3006023:
+                compile_options = ', '.join(map(lambda row: row[0], conn.execute('PRAGMA compile_options;')))
+                logger.info('SQLite Library Compile Options: ' + compile_options)
+            #There is no specific version requirement as yet, so we just use the
+            #first version that was included with Python.
+            if sqlite_version_number < 3000008:
+                logger.error('This version of SQLite is too old. PyBitmessage requires SQLite 3.0.8 or later')
+                return False
+            return True
+        except sqlite3.Error:
+            logger.exception('An exception occured while checking sqlite.')
+            return False
+    finally:
+        if conn:
+            conn.close()
+
+def check_openssl():
+    try:
+        import ctypes
+    except ImportError:
+        logger.error('Unable to check OpenSSL. The ctypes module is not available.')
+        return False
+
+    #We need to emulate the way PyElliptic searches for OpenSSL.
+    if sys.platform == 'win32':
+        paths = ['libeay32.dll']
+        if getattr(sys, 'frozen', False):
+            import os.path
+            paths.append(os.path.join(sys._MEIPASS, 'libeay32.dll'))
+    else:
+        paths = ['libcrypto.so']
+    if sys.platform == 'darwin':
+        paths.extend([
+            'libcrypto.dylib',
+            '/usr/local/opt/openssl/lib/libcrypto.dylib',
+            './../Frameworks/libcrypto.dylib'
+        ])
+    import re
+    if re.match(r'linux|darwin|freebsd', sys.platform):
+        try:
+            import ctypes.util
+            path = ctypes.util.find_library('ssl')
+            if path not in paths:
+                paths.append(path)
+        except:
+            pass
+
+    SSLEAY_VERSION = 0
+    SSLEAY_CFLAGS = 2
+
+    cflags_regex = re.compile(r'(?:OPENSSL_NO_)(AES|EC|ECDH|ECDSA)(?!\w)')
+
+    for path in paths:
+        logger.info('Checking OpenSSL at ' + path)
+        try:
+            library = ctypes.CDLL(path)
+        except OSError:
+            continue
+        logger.info('OpenSSL Name: ' + library._name)
+        try:
+            library.SSLeay.restype = ctypes.c_long
+            library.SSLeay_version.restype = ctypes.c_char_p
+            library.SSLeay_version.argtypes = [ctypes.c_int]
+        except AttributeError:
+            logger.error('Cannot determine version of this OpenSSL library.')
+            return False
+        logger.info('OpenSSL Version: ' + library.SSLeay_version(SSLEAY_VERSION))
+        compile_options = library.SSLeay_version(SSLEAY_CFLAGS)
+        logger.info('OpenSSL Compile Options: ' + compile_options)
+        openssl_hexversion = library.SSLeay()
+        #PyElliptic uses EVP_CIPHER_CTX_new and EVP_CIPHER_CTX_free which were
+        #introduced in 0.9.8b.
+        if openssl_hexversion < 0x90802F:
+            logger.error('This OpenSSL library is too old. PyBitmessage requires OpenSSL 0.9.8b or later with AES, Elliptic Curves (EC), ECDH, and ECDSA enabled.')
+            return False
+        matches = cflags_regex.findall(compile_options)
+        if len(matches) > 0:
+            logger.error('This OpenSSL library is missing the following required features: ' + ', '.join(matches) + '. PyBitmessage requires OpenSSL 0.9.8b or later with AES, Elliptic Curves (EC), ECDH, and ECDSA enabled.')
+            return False
+        return True
+    return False
+
+#TODO: The minimum versions of pythondialog and dialog need to be determined
+def check_curses():
+    if sys.hexversion < 0x20600F0:
+        logger.error('The curses interface requires Python 2.6 or later, the pythondialog package and the dialog utility.')
+        return False
+    try:
+        import curses
+    except ImportError:
+        logger.error('The curses interface can not be used. The curses module is not available.')
+        return False
+    logger.info('curses Module Version: ' + curses.version)
+    try:
+        import dialog
+    except ImportError:
+        logger.error('The curses interface can not be used. The pythondialog package is not available.')
+        return False
+    logger.info('pythondialog Package Version: ' + dialog.__version__)
+    dialog_util_version = dialog.Dialog().cached_backend_version
+    #The pythondialog author does not like Python2 str, so we have to use
+    #unicode for just the version otherwise we get the repr form which includes
+    #the module and class names along with the actual version.
+    logger.info('dialog Utility Version' + unicode(dialog_util_version))
+    return True
+
+def check_pyqt():
+    try:
+        import PyQt4.QtCore
+    except ImportError:
+        logger.error('The PyQt4 package is not available. PyBitmessage requires PyQt 4.8 or later and Qt 4.7 or later.')
+        return False
+    logger.info('PyQt Version: ' + PyQt4.QtCore.PYQT_VERSION_STR)
+    logger.info('Qt Version: ' + PyQt4.QtCore.QT_VERSION_STR)
+    passed = True
+    if PyQt4.QtCore.PYQT_VERSION < 0x40800:
+        logger.error('This version of PyQt is too old. PyBitmessage requries PyQt 4.8 or later.')
+        passed = False
+    if PyQt4.QtCore.QT_VERSION < 0x40700:
+        logger.error('This version of Qt is too old. PyBitmessage requries Qt 4.7 or later.')
+        passed = False
+    return passed
+
+def check_dependencies(verbose = False, optional = False):
+    if verbose:
+        logger.setLevel(logging.INFO)
+
+    has_all_dependencies = True
+
+    #Python 2.7.3 is the required minimum. Python 3+ is not supported, but it is
+    #still useful to provide information about our other requirements.
+    logger.info('Python version: %s', sys.version)
+    if sys.hexversion < 0x20703F0:
+        logger.error('PyBitmessage requires Python 2.7.3 or greater (but not Python 3+)')
+        has_all_dependencies = False
+    if sys.hexversion >= 0x3000000:
+        logger.error('PyBitmessage does not support Python 3+. Python 2.7.5 or greater is required.')
+        has_all_dependencies = False
+
+    check_functions = [check_hashlib, check_sqlite, check_openssl]
+    if optional:
+        check_functions.extend([check_pyqt, check_curses])
+
+    #Unexpected exceptions are handled here
+    for check in check_functions:
+        try:
+            has_all_dependencies &= check()
+        except:
+            logger.exception(check.__name__ + ' failed unexpectedly.')
+            has_all_dependencies = False
+        
+    if not has_all_dependencies:
+        logger.critical('PyBitmessage cannot start. One or more dependencies are unavailable.')
+        sys.exit()
+
+if __name__ == '__main__':
+    check_dependencies(True, True)
+