userland-fetch revision 3533
#!/usr/bin/python2.6
#
# CDDL HEADER START
#
# The contents of this file are subject to the terms of the
# Common Development and Distribution License (the "License").
# You may not use this file except in compliance with the License.
#
# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
# or http://www.opensolaris.org/os/licensing.
# See the License for the specific language governing permissions
# and limitations under the License.
#
# When distributing Covered Code, include this CDDL HEADER in each
# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
# If applicable, add the following below this CDDL HEADER, with the
# fields enclosed by brackets "[]" replaced with your own identifying
# information: Portions Copyright [yyyy] [name of copyright owner]
#
# CDDL HEADER END
#
# Copyright (c) 2010, 2014, Oracle and/or its affiliates. All rights reserved.
#
#
# userland-fetch - a file download utility
#
# A simple program similiar to wget(1), but handles local file copy, ignores
# directories, and verifies file hashes.
#
import errno
import os
import sys
import shutil
import subprocess
from urllib import splittype
from urllib2 import urlopen
import hashlib
def printIOError(e, txt):
""" Function to decode and print IOError type exception """
print "I/O Error: " + txt + ": "
try:
(code, message) = e
print str(message) + " (" + str(code) + ")"
except:
print str(e)
def validate_signature(path, signature):
"""Given paths to a file and a detached PGP signature, verify that
the signature is valid for the file. Current configuration allows for
unrecognized keys to be downloaded as necessary."""
# Find the root of the repo so that we can point GnuPG at the right
# configuration and keyring.
proc = subprocess.Popen(["hg", "root"], stdout=subprocess.PIPE)
proc.wait()
if proc.returncode != 0:
return False
out, err = proc.communicate()
gpgdir = os.path.join(out.strip(), "tools", ".gnupg")
# Skip the permissions warning: none of the information here is private,
# so not having to worry about getting mercurial keeping the directory
# unreadable is just simplest.
try:
proc = subprocess.Popen(["gpg2", "--verify",
"--no-permission-warning", "--homedir", gpgdir, signature,
path], stdin=open("/dev/null"),
stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
except OSError as e:
# If the executable simply couldn't be found, just skip the
# validation.
if e.errno == errno.ENOENT:
return False
raise
proc.wait()
if proc.returncode != 0:
# Only print GnuPG's output when there was a problem.
print proc.stdout.read()
return False
return True
def validate(file, hash):
"""Given a file-like object and a hash string, verify that the hash
matches the file contents."""
try:
algorithm, hashvalue = hash.split(':')
except:
algorithm = "sha256"
# force migration away from sha1
if algorithm == "sha1":
algorithm = "sha256"
try:
m = hashlib.new(algorithm)
except ValueError:
return False
while True:
try:
block = file.read()
except IOError, err:
print str(err),
break
m.update(block)
if block == '':
break
return "%s:%s" % (algorithm, m.hexdigest())
def validate_container(filename, hash):
"""Given a file path and a hash string, verify that the hash matches the
file contents."""
try:
file = open(filename, 'r')
except IOError as e:
printIOError(e, "Can't open file " + filename)
return False
return validate(file, hash)
def validate_payload(filename, hash):
"""Given a file path and a hash string, verify that the hash matches the
payload (uncompressed content) of the file."""
import re
import gzip
import bz2
expr_bz = re.compile('.+\.bz2$', re.IGNORECASE)
expr_gz = re.compile('.+\.gz$', re.IGNORECASE)
expr_tgz = re.compile('.+\.tgz$', re.IGNORECASE)
try:
if expr_bz.match(filename):
file = bz2.BZ2File(filename, 'r')
elif expr_gz.match(filename):
file = gzip.GzipFile(filename, 'r')
elif expr_tgz.match(filename):
file = gzip.GzipFile(filename, 'r')
else:
return False
except IOError as e:
printIOError(e, "Can't open archive " + filename)
return False
return validate(file, hash)
def download(url, filename=None, quiet=False):
"""Download the content at the given URL to the given filename
(defaulting to the basename of the URL if not given. If 'quiet' is
True, throw away any error messages. Returns the name of the file to
which the content was donloaded."""
src = None
try:
src = urlopen(url)
except IOError as e:
if not quiet:
printIOError(e, "Can't open url " + url)
return None
# 3xx, 4xx and 5xx (f|ht)tp codes designate unsuccessfull action
if 3 <= int(src.getcode()/100) <= 5:
if not quiet:
print "Error code: " + str(src.getcode())
return None
if filename == None:
filename = src.geturl().split('/')[-1]
try:
dst = open(filename, 'wb');
except IOError as e:
if not quiet:
printIOError(e, "Can't open file " + filename + " for writing")
src.close()
return None
while True:
block = src.read()
if block == '':
break;
dst.write(block)
src.close()
dst.close()
# return the name of the file that we downloaded the data to.
return filename
def download_paths(search, filename, url):
"""Returns a list of URLs where the file 'filename' might be found,
using 'url', 'search', and $DOWNLOAD_SEARCH_PATH as places to look.
If 'filename' is None, then the list will simply contain 'url'.
"""
urls = list()
if filename != None:
tmp = os.getenv('DOWNLOAD_SEARCH_PATH')
if tmp:
search += tmp.split(' ')
file = os.path.basename(filename)
urls = [ base + '/' + file for base in search ]
# filename should always be first
if filename in urls:
urls.remove(filename)
urls.insert(0, filename)
# command line url is a fallback, so it's last
if url != None and url not in urls:
urls.append(url)
return urls
def download_from_paths(search_list, file_arg, url, link_arg, quiet=False):
"""Attempts to download a file from a number of possible locations.
Generates a list of paths where the file ends up on the local
filesystem. This is a generator because while a download might be
successful, the signature or hash may not validate, and the caller may
want to try again from the next location. The 'link_arg' argument is a
boolean which, when True, specifies that if the source is not a remote
URL and not already found where it should be, to make a symlink to the
source rather than copying it.
"""
for url in download_paths(search_list, file_arg, url):
if not quiet:
print "Source %s..." % url,
scheme, path = splittype(url)
name = file_arg
if scheme in [ None, 'file' ]:
if os.path.exists(path) == False:
if not quiet:
print "not found, skipping file copy"
continue
elif name and name != path:
if link_arg == False:
if not quiet:
print "\n copying..."
shutil.copy2(path, name)
else:
if not quiet:
print "\n linking..."
os.symlink(path, name)
elif scheme in [ 'http', 'https', 'ftp' ]:
if not quiet:
print "\n downloading...",
name = download(url, file_arg, quiet)
if name == None:
if not quiet:
print "failed"
continue
yield name
def usage():
print "Usage: %s [-f|--file (file)] [-l|--link] [-h|--hash (hash)] " \
"[-s|--search (search-dir)] [-S|--sigurl (signature-url)] --url (url)" % \
(sys.argv[0].split('/')[-1])
sys.exit(1)
def main():
import getopt
# FLUSH STDOUT
sys.stdout = os.fdopen(sys.stdout.fileno(), 'w', 0)
file_arg = None
link_arg = False
hash_arg = None
url_arg = None
sig_arg = None
search_list = list()
try:
opts, args = getopt.getopt(sys.argv[1:], "f:h:ls:S:u:",
["file=", "link", "hash=", "search=", "sigurl=", "url="])
except getopt.GetoptError, err:
print str(err)
usage()
for opt, arg in opts:
if opt in [ "-f", "--file" ]:
file_arg = arg
elif opt in [ "-l", "--link" ]:
link_arg = True
elif opt in [ "-h", "--hash" ]:
hash_arg = arg
elif opt in [ "-s", "--search" ]:
search_list.append(arg)
elif opt in [ "-S", "--sigurl" ]:
sig_arg = arg
elif opt in [ "-u", "--url" ]:
url_arg = arg
else:
assert False, "unknown option"
if url_arg == None:
usage()
for name in download_from_paths(search_list, file_arg, url_arg, link_arg):
print "\n validating signature...",
sig_valid = False
if not sig_arg:
print "skipping (no signature URL)"
else:
# Put the signature file in the same directory as the
# file we're downloading.
sig_file = os.path.join(
os.path.dirname(file_arg),
os.path.basename(sig_arg))
# Validate with the first signature we find.
for sig_file in download_from_paths(search_list, sig_file,
sig_arg, link_arg, True):
if sig_file:
if validate_signature(name, sig_file):
print "ok"
sig_valid = True
else:
print "failed"
break
else:
continue
else:
print "failed (couldn't fetch signature)"
print " validating hash...",
realhash = validate_container(name, hash_arg)
if not hash_arg:
print "skipping (no hash)"
print "hash is: %s" % realhash
elif realhash == hash_arg:
print "ok"
else:
payloadhash = validate_payload(name, hash_arg)
if payloadhash == hash_arg:
print "ok"
else:
# If the signature validated, then we assume
# that the expected hash is just a typo, but we
# warn just in case.
if sig_valid:
print "invalid hash!"
else:
print "corruption detected"
print " expected: %s" % hash_arg
print " actual: %s" % realhash
print " payload: %s" % payloadhash
# An invalid hash shouldn't cause us to remove
# the target file if the signature was valid.
if not sig_valid:
try:
os.remove(name)
except OSError:
pass
continue
sys.exit(0)
sys.exit(1)
if __name__ == "__main__":
main()