mirror of
https://github.com/GNS3/gns3-server.git
synced 2024-12-19 21:07:57 +00:00
218 lines
8.2 KiB
Python
218 lines
8.2 KiB
Python
# -*- coding: utf-8 -*-
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#
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# Copyright (C) 2014 GNS3 Technologies Inc.
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import os
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import hashlib
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from ..config import Config
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from . import force_unix_path
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from io import DEFAULT_BUFFER_SIZE
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import logging
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log = logging.getLogger(__name__)
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def list_images(emulator_type):
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"""
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Scan directories for available image for a given emulator type
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:param emulator_type: emulator type (dynamips, qemu, iou)
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"""
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files = set()
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images = []
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server_config = Config.instance().get_section_config("Server")
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general_images_directory = os.path.expanduser(server_config.get("images_path", "~/GNS3/images"))
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# Subfolder of the general_images_directory specific to this emulator type
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default_directory = default_images_directory(emulator_type)
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for directory in images_directories(emulator_type):
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# We limit recursion to path outside the default images directory
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# the reason is in the default directory manage file organization and
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# it should be flat to keep things simple
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recurse = True
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if os.path.commonprefix([directory, general_images_directory]) == general_images_directory:
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recurse = False
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directory = os.path.normpath(directory)
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for root, _, filenames in _os_walk(directory, recurse=recurse):
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for filename in filenames:
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if filename in files:
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log.debug("File {} has already been found, skipping...".format(filename))
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continue
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if filename.endswith(".md5sum") or filename.startswith("."):
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continue
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files.add(filename)
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filesize = os.stat(os.path.join(root, filename)).st_size
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if filesize < 7:
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log.debug("File {} is too small to be an image, skipping...".format(filename))
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continue
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try:
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with open(os.path.join(root, filename), "rb") as f:
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# read the first 7 bytes of the file.
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elf_header_start = f.read(7)
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if emulator_type == "dynamips" and elf_header_start != b'\x7fELF\x01\x02\x01':
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# IOS images must start with the ELF magic number, be 32-bit, big endian and have an ELF version of 1
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log.warning("IOS image {} does not start with a valid ELF magic number, skipping...".format(filename))
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continue
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elif emulator_type == "iou" and elf_header_start != b'\x7fELF\x02\x01\x01' and elf_header_start != b'\x7fELF\x01\x01\x01':
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# IOU images must start with the ELF magic number, be 32-bit or 64-bit, little endian and have an ELF version of 1
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log.warning("IOU image {} does not start with a valid ELF magic number, skipping...".format(filename))
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continue
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elif emulator_type == "qemu" and elf_header_start[:4] == b'\x7fELF':
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# QEMU images should not start with an ELF magic number
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log.warning("QEMU image {} starts with an ELF magic number, skipping...".format(filename))
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continue
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# It the image is located in the standard directory the path is relative
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if os.path.commonprefix([root, default_directory]) != default_directory:
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path = os.path.join(root, filename)
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else:
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path = os.path.relpath(os.path.join(root, filename), default_directory)
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images.append(
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{
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"filename": filename,
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"path": force_unix_path(path),
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"md5sum": md5sum(os.path.join(root, filename)),
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"filesize": filesize
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}
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)
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except OSError as e:
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log.warning("Can't add image {}: {}".format(path, str(e)))
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return images
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def _os_walk(directory, recurse=True, **kwargs):
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"""
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Work like os.walk but if recurse is False just list current directory
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"""
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if recurse:
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for root, dirs, files in os.walk(directory, **kwargs):
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yield root, dirs, files
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else:
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files = []
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for filename in os.listdir(directory):
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if os.path.isfile(os.path.join(directory, filename)):
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files.append(filename)
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yield directory, [], files
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def default_images_directory(emulator_type):
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"""
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:returns: Return the default directory for a node type
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"""
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server_config = Config.instance().get_section_config("Server")
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img_dir = os.path.expanduser(server_config.get("images_path", "~/GNS3/images"))
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if emulator_type == "qemu":
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return os.path.join(img_dir, "QEMU")
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elif emulator_type == "iou":
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return os.path.join(img_dir, "IOU")
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elif emulator_type == "dynamips":
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return os.path.join(img_dir, "IOS")
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else:
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raise NotImplementedError("%s node type is not supported", emulator_type)
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def images_directories(emulator_type):
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"""
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Return all directories where we will look for images
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by priority
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:param emulator_type: Type of emulator
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"""
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server_config = Config.instance().get_section_config("Server")
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paths = []
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img_dir = os.path.expanduser(server_config.get("images_path", "~/GNS3/images"))
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type_img_directory = default_images_directory(emulator_type)
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try:
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os.makedirs(type_img_directory, exist_ok=True)
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paths.append(type_img_directory)
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except (OSError, PermissionError):
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pass
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for directory in server_config.get("additional_images_path", "").split(";"):
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paths.append(directory)
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# Compatibility with old topologies we look in parent directory
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paths.append(img_dir)
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# Return only the existing paths
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return [force_unix_path(p) for p in paths if os.path.exists(p)]
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def md5sum(path, stopped_event=None):
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"""
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Return the md5sum of an image and cache it on disk
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:param path: Path to the image
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:param stopped_event: In case you execute this function on thread and would like to have possibility
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to cancel operation pass the `threading.Event`
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:returns: Digest of the image
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"""
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if path is None or len(path) == 0 or not os.path.exists(path):
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return None
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try:
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with open(path + '.md5sum') as f:
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md5 = f.read().strip()
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if len(md5) == 32:
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return md5
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# Unicode error is when user rename an image to .md5sum ....
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except (OSError, UnicodeDecodeError):
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pass
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try:
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m = hashlib.md5()
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log.debug("Calculating MD5 sum of `{}`".format(path))
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with open(path, 'rb') as f:
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while True:
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if stopped_event is not None and stopped_event.is_set():
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log.error("MD5 sum calculation of `{}` has stopped due to cancellation".format(path))
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return
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buf = f.read(DEFAULT_BUFFER_SIZE)
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if not buf:
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break
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m.update(buf)
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digest = m.hexdigest()
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except OSError as e:
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log.error("Can't create digest of %s: %s", path, str(e))
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return None
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try:
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with open('{}.md5sum'.format(path), 'w+') as f:
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f.write(digest)
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except OSError as e:
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log.error("Can't write digest of %s: %s", path, str(e))
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return digest
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def remove_checksum(path):
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"""
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Remove the checksum of an image from cache if exists
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"""
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path = '{}.md5sum'.format(path)
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if os.path.exists(path):
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os.remove(path)
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