NEWS for Version 1.16 (2020-01-08)

NEWS for Version 1.16 (2020-01-08)

Postby hbuhrmester » 08.01.2020, 21:35

NEWS for Version 1.16

Release date: 2020-01-08
Intended compatibility: WSUS Offline Update 11.8.3


Bug fixes

The download of wsusscn2.cab indicated success, when the integrity check with cabextract failed

The integrity of the WSUS offline scan file wsusscn2.cab can be tested with cabextract -t. If this test fails, the script would still create a file timestamp-wsus-all-glb.txt. This will postpone the next download/validation of this task for one day.

Timestamp files should only be created to indicate successful download runs. Then they prevent the repeated evaluation of the same task in successive download runs. The next evaluation of the WSUS Offline Update configuration files will be postponed for one day (21 hours).

In case of the WSUS offline scan file wsusscn2.cab, a failed download should be retried as soon as possible. Therefore, no timestamp files should be created for failed download tasks.

Static download files in the ../static/custom directory were skipped

The calculation of static download links ignored custom files ../static/custom/StaticDownloadLinks-*.txt, if the original files in the ../static directory were all empty.

Corrected the spelling of files and directories

The file 71-make-shapshot.bash was renamed to 71-make-snapshot.bash.

The noun "licence" is valid British English, but the directory was renamed to "license" for consistency with the usage of American English in other places.


User visible changes

Revised messages for the update of configuration files

The messages for the update of the configuration files for WSUS Offline Update were revised, to better indicate the different steps.


Internal changes

Better compatibility with FreeBSD 12.1, thanks to TheFlipside

FreeBSD uses an up to date bash, but there are small differences in the core utilities cp, date, mktemp, sed and unzip. Sometimes, even the same options don't work the same in GNU/Linux and FreeBSD, e.g. sed -i and unzip -u. This has been partially tested with a virtual machine from https://www.freebsd.org/where.html.

Known differences were fixed, but these virtual machines are too small and too slow to really run the whole download script, so there may be more to be found.

This was first reported in:



Documentation

New file "Differences_between_GNU-Linux_and_FreeBSD.txt"

This file describes the found differences between the GNU/Linux and FreeBSD utilities cp, date, mktemp, sed and unzip. It also discusses possible solutions and workarounds.

Updated installations guides

The files Installation_Guide.txt and Installationsanleitung.txt were updated to include hints for FreeBSD 12.1.


Downloads

The download links for this version are:


Link for the online check at VirusTotal. Note, that the URL includes the SHA-256 hash of the archive:


The hashes for the archive sh-1.16.tgz are:
Code: Select all
MD5:      8b4aef4bcb67cd9be65e3705da312b53
SHA-256:  87b7d011fffa49b82b8144110e7ab55743df8a17ef35f19cd3e1694eede22fda



Further Reading

The first three posts in the original topic A complete rewrite of the Linux scripts are still being updated, to point to the latest version:

hbuhrmester
 
Posts: 459
Joined: 11.10.2013, 20:59

Differences between GNU/Linux and FreeBSD utilities

Postby hbuhrmester » 08.01.2020, 21:50

Differences between GNU/Linux and FreeBSD core utilities

There are some differences between the standard utilities in FreeBSD 12.1 and GNU/Linux. In most cases, some common ground can be found, but a few utilities require workarounds.


Differences in cp

The FreeBSD cp does not have the options -t and -u of GNU/Linux cp.

The option -t is meant to explicitly set the target directory. This may be useful, if there are many command line arguments, which might create ambiguities. But if there are only two arguments, then there will be no ambiguities between source and destination.

With the option -u, GNU/Linux cp will update files: It only copies files, if the source file is newer than the target file, or if the target file does not exist. This avoids needlessly copying the same file on each run.

Comparing the files in the shell should get the same results: The comparison operator -nt is true, if the first file is newer than the second, or if the second file does not exist.

Code: Select all
if [[ "${source}" -nt "${target}" ]]
then
    cp -a "${source}" "${target}"
fi



Trailing slashes after source directories should be avoided, because they are treated differently in GNU/Linux and in FreeBSD cp.


According to the manual page, the options -r -l -s -v -x -n are all "deprecated" in FreeBSD cp.


Differences in date

Simple options like "-r filename" work the same in GNU/Linux and in FreeBSD date, but date format conversions and date calculations are handled differently:


Date format conversions

In GNU/Linux date, an existing date string can be used as input with the option -d. Well defined formats like ISO 8601 or RFC 3339 are recognized automatically. There is no option to define custom input formats. If the date string does not set the hours, minutes and seconds, then the time will be set to 00:00:00.

The output format is specified with sequences like '+%s' for the seconds since 1970, or '+%u' for the day of week as a decimal number (1..7).

To convert a date in ISO 8601 format (days only) and UTC to seconds, we could use:

Code: Select all
~$ date_string="2019-12-11"
~$ date -u -d "${date_string}" '+%s'
1576022400


In FreeBSD date, an existing date string can be directly used as input. This will usually set the time. The option -j must be used to not set the time. The default input format would be all fields joined together, e.g. "201912110000.00". Custom input formats can be specified with the option -f. If the date string does not specify the hours, minutes and seconds, then the time will be set to the current time.

To convert a date in UTC to seconds, we could use either:

Code: Select all
~$ date_string="201912110000.00"
~$ date -j -u "${date_string}" '+%s'
1576022400

~$ date_string="2019-12-11 00:00:00"
~$ date -j -u -f "%Y-%m-%d %H:%M:%S" "${date_string}" '+%s'
1576022400



Date calculations

GNU/Linux date recognizes some expressions in plain English. To get the previous month, we can construct a date string for the 15th of the current month, and then add "last month" literally.

Code: Select all
~$ this_month="$(date -u '+%Y-%m')"
~$ echo "${this_month}"
2019-12
~$ last_month="$(date -u -d "${this_month}-15 last month" '+%Y-%m')"
~$ echo "${last_month}"
2019-11


With FreeBSD date, the option -v can be used repeatedly to set absolute or relative dates.

-v 15d sets the date to the 15th of the current month
-v -1m means "minus one month" and subtracts about 30 days

Together, this should reveal the previous month:

Code: Select all
~$ date -u -v 15d -v 0H -v 0M -v 0S -v -1m '+%Y-%m'
2019-11



Differences in mktemp

In FreeBSD, the file or directory name must end with the pattern .XXXXXX, while it could be used in different places in GNU/Linux.

The option -p does not exist in FreeBSD mktemp. Using only the option -d for directories should work for both sides:

Code: Select all
temp_dir="$(mktemp -d /tmp/download-updates.XXXXXX)"



Differences in sed

There are slight differences, how sed "inline" works in FreeBSD 12.1 and GNU/Linux:

The FreeBSD sed always expects a file extension for backup files after the option -i, even if it is only an empty string. Otherwise, the next two parameters are interpreted as a file extension and the sed script command. Then FreeBSD sed may print error messages like:

Code: Select all
~$ sed -i "s/w60=off/w60=on/" update-generator.ini
sed: 1: "update-generator.ini": invalid command code u


It is possible to specify an empty string as a file extension:

Code: Select all
~$ sed -i "" "s/w60=off/w60=on/" update-generator.ini


Then FreeBSD sed will not report an error, and the script command is evaluated as expected.

With GNU/Linux sed, it is just the other way around: The first version works, but the second version creates an error.

The only way, that works for both FreeBSD and GNU/Linux sed, is to actually provide a file extension for backup files:

Code: Select all
~$ sed -i.bak "s/w60=off/w60=on/" update-generator.ini



Differences in unzip

The unzip option -u is meant to update existing files and create new files if needed. It works differently in GNU/Linux and in FreeBSD unzip.

The GNU/Linux unzip will ask for confirmation before overwriting files. This query will be skipped, if the additional option -o is used.

For example, if both sigcheck.exe and sigcheck64.exe are new, then we might get for GNU/Linux unzip:

Code: Select all
~$ unzip -u Sigcheck.zip
Archive:  Sigcheck.zip
replace sigcheck.exe? [y]es, [n]o, [A]ll, [N]one, [r]ename: n
replace sigcheck64.exe? [y]es, [n]o, [A]ll, [N]one, [r]ename: n
  inflating: Eula.txt
~$ unzip -u -o Sigcheck.zip
Archive:  Sigcheck.zip
  inflating: sigcheck.exe
  inflating: sigcheck64.exe


The FreeBSD unzip considers the options -u and -o "contradictory". The option -u updates existing files without prompting for confirmation.

Code: Select all
~$ unzip -u -o Sigcheck.zip
unzip: -n, -o and -u are contradictory
~$ unzip -u Sigcheck.zip
Archive:  Sigcheck.zip
 extracting: sigcheck.exe
 extracting: sigcheck64.exe
 extracting: Eula.txt


Since the script download-updates.bash is meant to run without user interaction, these options need to be stored in a variable:

Code: Select all
unzip_upgrade=""
case "${kernel_name}" in
    Linux | CYGWIN*)
        unzip_upgrade="unzip -u -o"
    ;;
    Darwin | FreeBSD | NetBSD | OpenBSD)
        unzip_upgrade="unzip -u"
    ;;
    *)
        echo "Unknown operating system ${kernel_name}, ${OSTYPE}"
        exit 1
    ;;
esac


${unzip_upgrade} without quotes is then used in places, where unzip -u -o was used for GNU/Linux only.
hbuhrmester
 
Posts: 459
Joined: 11.10.2013, 20:59


Return to Linux

Who is online

Users browsing this forum: No registered users and 4 guests