#!/usr/bin/python # -*- coding: utf-8 -*- # Copyright: (c) 2021, quidame <quidame@poivron.org> # GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt) from __future__ import absolute_import, division, print_function __metaclass__ = type DOCUMENTATION = r''' --- module: filesize short_description: Create a file with a given size, or resize it if it exists description: - This module is a simple wrapper around C(dd) to create, extend or truncate a file, given its size. It can be used to manage swap files (that require contiguous blocks) or alternatively, huge sparse files. author: - quidame (@quidame) version_added: "3.0.0" options: path: description: - Path of the regular file to create or resize. type: path required: true size: description: - Requested size of the file. - The value is a number (either C(int) or C(float)) optionally followed by a multiplicative suffix, that can be one of C(B) (bytes), C(KB) or C(kB) (= 1000B), C(MB) or C(mB) (= 1000kB), C(GB) or C(gB) (= 1000MB), and so on for C(T), C(P), C(E), C(Z) and C(Y); or alternatively one of C(K), C(k) or C(KiB) (= 1024B); C(M), C(m) or C(MiB) (= 1024KiB); C(G), C(g) or C(GiB) (= 1024MiB); and so on. - If the multiplicative suffix is not provided, the value is treated as an integer number of blocks of I(blocksize) bytes each (float values are rounded to the closest integer). - When the I(size) value is equal to the current file size, does nothing. - When the I(size) value is bigger than the current file size, bytes from I(source) (if I(sparse) is not C(false)) are appended to the file without truncating it, in other words, without modifying the existing bytes of the file. - When the I(size) value is smaller than the current file size, it is truncated to the requested value without modifying bytes before this value. - That means that a file of any arbitrary size can be grown to any other arbitrary size, and then resized down to its initial size without modifying its initial content. type: raw required: true blocksize: description: - Size of blocks, in bytes if not followed by a multiplicative suffix. - The numeric value (before the unit) C(MUST) be an integer (or a C(float) if it equals an integer). - If not set, the size of blocks is guessed from the OS and commonly results in C(512) or C(4096) bytes, that is used internally by the module or when I(size) has no unit. type: raw source: description: - Device or file that provides input data to provision the file. - This parameter is ignored when I(sparse=true). type: path default: /dev/zero force: description: - Whether or not to overwrite the file if it exists, in other words, to truncate it from 0. When C(true), the module is not idempotent, that means it always reports I(changed=true). - I(force=true) and I(sparse=true) are mutually exclusive. type: bool default: false sparse: description: - Whether or not the file to create should be a sparse file. - This option is effective only on newly created files, or when growing a file, only for the bytes to append. - This option is not supported on OpenBSD, Solaris and AIX. - I(force=true) and I(sparse=true) are mutually exclusive. type: bool default: false notes: - This module supports C(check_mode) and C(diff). requirements: - dd (Data Duplicator) in PATH extends_documentation_fragment: - ansible.builtin.files seealso: - name: dd(1) manpage for Linux description: Manual page of the GNU/Linux's dd implementation (from GNU coreutils). link: https://man7.org/linux/man-pages/man1/dd.1.html - name: dd(1) manpage for IBM AIX description: Manual page of the IBM AIX's dd implementation. link: https://www.ibm.com/support/knowledgecenter/ssw_aix_72/d_commands/dd.html - name: dd(1) manpage for Mac OSX description: Manual page of the Mac OSX's dd implementation. link: https://www.unix.com/man-page/osx/1/dd/ - name: dd(1M) manpage for Solaris description: Manual page of the Oracle Solaris's dd implementation. link: https://docs.oracle.com/cd/E36784_01/html/E36871/dd-1m.html - name: dd(1) manpage for FreeBSD description: Manual page of the FreeBSD's dd implementation. link: https://www.freebsd.org/cgi/man.cgi?dd(1) - name: dd(1) manpage for OpenBSD description: Manual page of the OpenBSD's dd implementation. link: https://man.openbsd.org/dd - name: dd(1) manpage for NetBSD description: Manual page of the NetBSD's dd implementation. link: https://man.netbsd.org/dd.1 ''' EXAMPLES = r''' - name: Create a file of 1G filled with null bytes community.general.filesize: path: /var/bigfile size: 1G - name: Extend the file to 2G (2*1024^3) community.general.filesize: path: /var/bigfile size: 2G - name: Reduce the file to 2GB (2*1000^3) community.general.filesize: path: /var/bigfile size: 2GB - name: Fill a file with random bytes for backing a LUKS device community.general.filesize: path: ~/diskimage.luks size: 512.0 MiB source: /dev/urandom - name: Take a backup of MBR boot code into a file, overwriting it if it exists community.general.filesize: path: /media/sdb1/mbr.bin size: 440B source: /dev/sda force: true - name: Create/resize a sparse file of/to 8TB community.general.filesize: path: /var/local/sparsefile size: 8TB sparse: true - name: Create a file with specific size and attributes, to be used as swap space community.general.filesize: path: /var/swapfile size: 2G blocksize: 512B mode: u=rw,go= owner: root group: root ''' RETURN = r''' cmd: description: Command executed to create or resize the file. type: str returned: when changed or failed sample: /usr/bin/dd if=/dev/zero of=/var/swapfile bs=1048576 seek=3072 count=1024 filesize: description: Dictionary of sizes related to the file. type: dict returned: always contains: blocks: description: Number of blocks in the file. type: int sample: 500 blocksize: description: Size of the blocks in bytes. type: int sample: 1024 bytes: description: Size of the file, in bytes, as the product of C(blocks) and C(blocksize). type: int sample: 512000 iec: description: Size of the file, in human-readable format, following IEC standard. type: str sample: 500.0 KiB si: description: Size of the file, in human-readable format, following SI standard. type: str sample: 512.0 kB size_diff: description: Difference (positive or negative) between old size and new size, in bytes. type: int sample: -1234567890 returned: always path: description: Realpath of the file if it is a symlink, otherwise the same than module's param. type: str sample: /var/swap0 returned: always ''' import re import os import math from ansible.module_utils.basic import AnsibleModule from ansible.module_utils.common.text.converters import to_native # These are the multiplicative suffixes understood (or returned) by dd and # others (ls, df, lvresize, lsblk...). SIZE_UNITS = dict( B=1, kB=1000**1, KB=1000**1, KiB=1024**1, K=1024**1, k=1024**1, MB=1000**2, mB=1000**2, MiB=1024**2, M=1024**2, m=1024**2, GB=1000**3, gB=1000**3, GiB=1024**3, G=1024**3, g=1024**3, TB=1000**4, tB=1000**4, TiB=1024**4, T=1024**4, t=1024**4, PB=1000**5, pB=1000**5, PiB=1024**5, P=1024**5, p=1024**5, EB=1000**6, eB=1000**6, EiB=1024**6, E=1024**6, e=1024**6, ZB=1000**7, zB=1000**7, ZiB=1024**7, Z=1024**7, z=1024**7, YB=1000**8, yB=1000**8, YiB=1024**8, Y=1024**8, y=1024**8, ) def bytes_to_human(size, iec=False): """Return human-readable size (with SI or IEC suffix) from bytes. This is only to populate the returned result of the module, not to handle the file itself (we only rely on bytes for that). """ unit = 'B' for (u, v) in SIZE_UNITS.items(): if size < v: continue if iec: if 'i' not in u or size / v >= 1024: continue else: if v % 5 or size / v >= 1000: continue unit = u hsize = round(size / SIZE_UNITS[unit], 2) if unit == 'B': hsize = int(hsize) unit = re.sub(r'^(.)', lambda m: m.expand(r'\1').upper(), unit) if unit == 'KB': unit = 'kB' return '%s %s' % (str(hsize), unit) def smart_blocksize(size, unit, product, bsize): """Ensure the total size can be written as blocks*blocksize, with blocks and blocksize being integers. """ if not product % bsize: return bsize # Basically, for a file of 8kB (=8000B), system's block size of 4096 bytes # is not usable. The smallest integer number of kB to work with 512B blocks # is 64, the nexts are 128, 192, 256, and so on. unit_size = SIZE_UNITS[unit] if size == int(size): if unit_size > SIZE_UNITS['MiB']: if unit_size % 5: return SIZE_UNITS['MiB'] return SIZE_UNITS['MB'] return unit_size if unit == 'B': raise AssertionError("byte is the smallest unit and requires an integer value") if 0 < product < bsize: return product for bsz in (1024, 1000, 512, 256, 128, 100, 64, 32, 16, 10, 8, 4, 2): if not product % bsz: return bsz return 1 def split_size_unit(string, isint=False): """Split a string between the size value (int or float) and the unit. Support optional space(s) between the numeric value and the unit. """ unit = re.sub(r'(\d|\.)', r'', string).strip() value = float(re.sub(r'%s' % unit, r'', string).strip()) if isint and unit in ('B', ''): if int(value) != value: raise AssertionError("invalid blocksize value: bytes require an integer value") if not unit: unit = None product = int(round(value)) else: if unit not in SIZE_UNITS.keys(): raise AssertionError("invalid size unit (%s): unit must be one of %s, or none." % (unit, ', '.join(sorted(SIZE_UNITS, key=SIZE_UNITS.get)))) product = int(round(value * SIZE_UNITS[unit])) return value, unit, product def size_string(value): """Convert a raw value to a string, but only if it is an integer, a float or a string itself. """ if not isinstance(value, (int, float, str)): raise AssertionError("invalid value type (%s): size must be integer, float or string" % type(value)) return str(value) def size_spec(args): """Return a dictionary with size specifications, especially the size in bytes (after rounding it to an integer number of blocks). """ blocksize_in_bytes = split_size_unit(args['blocksize'], True)[2] if blocksize_in_bytes == 0: raise AssertionError("block size cannot be equal to zero") size_value, size_unit, size_result = split_size_unit(args['size']) if not size_unit: blocks = int(math.ceil(size_value)) else: blocksize_in_bytes = smart_blocksize(size_value, size_unit, size_result, blocksize_in_bytes) blocks = int(math.ceil(size_result / blocksize_in_bytes)) args['size_diff'] = round_bytes = int(blocks * blocksize_in_bytes) args['size_spec'] = dict(blocks=blocks, blocksize=blocksize_in_bytes, bytes=round_bytes, iec=bytes_to_human(round_bytes, True), si=bytes_to_human(round_bytes)) return args['size_spec'] def current_size(args): """Return the size of the file at the given location if it exists, or None.""" path = args['path'] if os.path.exists(path): if not os.path.isfile(path): raise AssertionError("%s exists but is not a regular file" % path) args['file_size'] = os.stat(path).st_size else: args['file_size'] = None return args['file_size'] def complete_dd_cmdline(args, dd_cmd): """Compute dd options to grow or truncate a file.""" if args['file_size'] == args['size_spec']['bytes'] and not args['force']: # Nothing to do. return list() bs = args['size_spec']['blocksize'] conv = list() # For sparse files (create, truncate, grow): write count=0 block. if args['sparse']: seek = args['size_spec']['blocks'] conv += ['sparse'] elif args['force'] or not os.path.exists(args['path']): # Create file seek = 0 elif args['size_diff'] < 0: # Truncate file seek = args['size_spec']['blocks'] elif args['size_diff'] % bs: # Grow file seek = int(args['file_size'] / bs) + 1 else: seek = int(args['file_size'] / bs) count = args['size_spec']['blocks'] - seek dd_cmd += ['bs=%s' % str(bs), 'seek=%s' % str(seek), 'count=%s' % str(count)] if conv: dd_cmd += ['conv=%s' % ','.join(conv)] return dd_cmd def main(): module = AnsibleModule( argument_spec=dict( path=dict(type='path', required=True), size=dict(type='raw', required=True), blocksize=dict(type='raw'), source=dict(type='path', default='/dev/zero'), sparse=dict(type='bool', default=False), force=dict(type='bool', default=False), ), supports_check_mode=True, add_file_common_args=True, ) args = dict(**module.params) diff = dict(before=dict(), after=dict()) if args['sparse'] and args['force']: module.fail_json(msg='parameters values are mutually exclusive: force=true|sparse=true') if not os.path.exists(os.path.dirname(args['path'])): module.fail_json(msg='parent directory of the file must exist prior to run this module') if not args['blocksize']: args['blocksize'] = str(os.statvfs(os.path.dirname(args['path'])).f_frsize) try: args['size'] = size_string(args['size']) args['blocksize'] = size_string(args['blocksize']) initial_filesize = current_size(args) size_descriptors = size_spec(args) except AssertionError as err: module.fail_json(msg=to_native(err)) expected_filesize = size_descriptors['bytes'] if initial_filesize: args['size_diff'] = expected_filesize - initial_filesize diff['after']['size'] = expected_filesize diff['before']['size'] = initial_filesize result = dict( changed=args['force'], size_diff=args['size_diff'], path=args['path'], filesize=size_descriptors) dd_bin = module.get_bin_path('dd', True) dd_cmd = [dd_bin, 'if=%s' % args['source'], 'of=%s' % args['path']] if expected_filesize != initial_filesize or args['force']: result['cmd'] = ' '.join(complete_dd_cmdline(args, dd_cmd)) if module.check_mode: result['changed'] = True else: result['rc'], dummy, result['stderr'] = module.run_command(dd_cmd) diff['after']['size'] = result_filesize = result['size_diff'] = current_size(args) if initial_filesize: result['size_diff'] = result_filesize - initial_filesize if not args['force']: result['changed'] = result_filesize != initial_filesize if result['rc']: msg = "dd error while creating file %s with size %s from source %s: see stderr for details" % ( args['path'], args['size'], args['source']) module.fail_json(msg=msg, **result) if result_filesize != expected_filesize: msg = "module error while creating file %s with size %s from source %s: file is %s bytes long" % ( args['path'], args['size'], args['source'], result_filesize) module.fail_json(msg=msg, **result) # dd follows symlinks, and so does this module, while file module doesn't. # If we call it, this is to manage file's mode, owner and so on, not the # symlink's ones. file_params = dict(**module.params) if os.path.islink(args['path']): file_params['path'] = result['path'] = os.path.realpath(args['path']) if args['file_size'] is not None: file_args = module.load_file_common_arguments(file_params) result['changed'] = module.set_fs_attributes_if_different(file_args, result['changed'], diff=diff) result['diff'] = diff module.exit_json(**result) if __name__ == '__main__': main()