Run this command across the source:
perl -pi.bak -e 's/(20[012][0-9])-20[12][012]/$1-2023/g' `git ls-files`
and remove changes to po{,-docs}/*.po{,t} (these will be regenerated
later when we run 'make dist').
In guestfs-tools commit 4fe8a03cd2d3 ('sysprep: remove lvm2's default
"system.devices" file', 2022-04-11), we disabled the use of LVM2's new
"devicesfile" feature, which could interfere with the cloning of virtual
machines.
We suspected in
https://bugzilla.redhat.com/show_bug.cgi?id=2072493#c6
that the same lvm2 feature could affect the libguestfs appliance itself,
but decided in
https://bugzilla.redhat.com/show_bug.cgi?id=2072493#c8https://bugzilla.redhat.com/show_bug.cgi?id=2072493#c10
that this would not be the case, because "appliance/init" already
constructed a pristine LVM_SYSTEM_DIR.
Unfortunately, that's not enough: due to the "use_devicesfile=1" default
(on RHEL9 anyway), some "lvm" invocation, possibly inside the
lvm-set-filter API, *creates* "$LVM_SYSTEM_DIR/devices/system.devices".
And then we get (minimally) warnings such as
> Please remove the lvm.conf global_filter, it is ignored with the devices
> file.
> Please remove the lvm.conf filter, it is ignored with the devices file.
when using the lvm-set-filter API.
Explicitly disable the "devices file" in "appliance/init", and also
whenever we rewrite "lvm.conf" -- that is, in set_filter()
[daemon/lvm-filter.c]. In the former, check for the feature by locating
the devicesfile-related utilities "lvmdevices" and "vgimportdevices". In
the C code, invoke the utilities with the "--help" option instead. (In
"appliance/init", I thought it was best not to call any lvm2 utilities
even with "--help", with our lvm2.conf still under construction there.) If
either utility is available, set "use_devicesfile = 0".
Cc: David Teigland <teigland@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1965941
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20220530141027.16167-1-lersek@redhat.com>
Acked-by: Richard W.M. Jones <rjones@redhat.com>
[lersek@redhat.com: style fix: break "devicesfile_feature" in the function
definition to a new line]
When the daemon starts up it creates a fresh (empty) LVM configuration
and starts up lvmetad (which depends on the LVM configuration).
However this appears to cause problems: Some types of PV seem to
require lvmetad and don't work without it
(https://bugzilla.redhat.com/show_bug.cgi?id=1581810). If we don't
start lvmetad earlier, the device nodes are not created.
Therefore move the whole initialization step into appliance/init.
Two further changes had to be made:
Now we are using lvmetad all the time, using vgchange is incorrect.
With lvmetad activated early we must use ‘pvscan --cache --activate ay’
to scan all disks for PVs and activate any VGs on them (although the
documentation is complex, confusing and contradictory so I'm not
completely sure about this).
The ‘lvm_system_dir’ local variable in ‘daemon/lvm-filter.c’
previously contained the path of the directory above $LVM_SYSTEM_DIR
(eg. $LVM_SYSTEM_DIR = "/etc/lvm", lvm_system_dir = "/etc"). As this
was highly confusing, I have changed it so the local variable and the
environment variable have identical contents. This involved removing
the ‘lvm/’ component from a couple of paths since it is now included
in the local variable.
LVM is fine with a completely empty configuration file (meaning "all
defaults"), so start with one instead of copying the system
configuration file.
Also this means we can very easily implement lvm_set_filter
functionality without using Augeas, since we no longer have to worry
about existing filters being present.
Thanks: Alasdair Kergon, Zdenek Kabelac.
GUESTFSD_EXT_CMD was used by OpenSUSE to track which external commands
are run by the daemon and package those commands into the appliance.
It is no longer used by recent SUSE builds, so remove it.
Thanks: Pino Toscano, Olaf Hering.
Currently lvmetad is started in init, and thus using the system
(= appliance) configuration of lvm. Later on, in the daemon, a local
copy of the lvm configuration is setup, and set it for use using the
LVM_SYSTEM_DIR environment variable: this means only the programmes
executed by the daemon will use the local lvm configuration, and not
lvmetad.
Thus manually start lvmetad from the daemon, right after having setup
the local lvm configuration, and still without failing if it cannot be
executed.
Additionally, since lvmetad now respects the right configuration, make
sure to update its cache when rescanning the VGs by passing --cache to
vgscan.
When editing the lvm configuration to set the LVM filter, edit the
'global_filter' key in addition to 'filter': the latter is not used when
lvmetad is running, when only the former works.
Declare most of the stringsbuf as CLEANUP_FREE_STRINGSBUF, so they are
freed completely on stack unwind: use take_stringsbuf() in return
places to take away from the stringsbuf its content, and remove all the
manual calls to free_stringslen (no more needed now).
This requires to not use free_stringslen anymore on failure in the
helper functions of stringsbuf, which now leave the content as-is (might
be still useful even on error).
This allows us to simplify the memory management of stringsbuf's, which
are not properly fully freed, fixing memory leaks in some error paths
(which were not calling free_stringslen).
Like with the previous commit, this replaces instances of:
if (something_bad) {
fprintf (stderr, "%s: error message\n", guestfs_int_program_name);
exit (EXIT_FAILURE);
}
with:
if (something_bad)
error (EXIT_FAILURE, 0, "error message");
(except in a few cases were errno was incorrectly being ignored, in
which case I have fixed that).
It's slightly more complex than the previous commit because we must be
careful to:
- Remove the program name (since error(3) prints it).
- Remove any trailing \n character from the message.
Candidates for replacement were found using:
pcregrep --buffer-size 10M -M '\bfprintf\b.*\n.*\bexit\b' `git ls-files`
Because of previous automated commits, such as changing 'guestfs___'
-> 'guestfs_int_', several function calls no longer lined up with
their parameters, and some lines were too long.
The bulk of this commit was done using emacs batch mode and the
technique described here:
http://www.cslab.pepperdine.edu/warford/BatchIndentationEmacs.html
The changes suggested by emacs were then reviewed by hand.
The way to set the filter for lvm devices was to open lvm.conf, look
for uncommented "filter =" lines and replace the configuration there.
This had the issue that if there is no uncommented filter line, then the
filter cannot be changed at all; considering newer lvm2 releases ship a
sample configuration with no uncommented filter lines, then the old way
became wrong and not sufficient.
Instead, take a copy of the upstream lvm.aug lens, with a simple change
to allow parsing also negative values in configuration, and install it
in the daemon. When asking to change the lvm filter, use augeas making
sure to use this custom lens for the lvm.conf copy used within the
appliance.
The second parameter passed into getline(3) is the size of the
allocated buffer, *NOT* the length of the returned line. This can be
confusing, so rename this parameter as 'allocsize' consistently
throughout the code.
This is just code motion.
Replace selected calls to 'perror (filename)' with:
fprintf (stderr, "syscall: %s: %m\n", filename);
so that more information is available about precisely which syscall
failed.
Note this is *not* reply_with_perror. These messages are only printed
in verbose output, for the benefit of debugging.
cp will fail if /etc/lvm is an empty directory. Copy the entire
directory and adjust environment variable.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
RWMJ:
- Fixed a couple of whitespace issues.
guestfsd calls many different tools. Keeping track of all of them is
error prone. This patch introduces a new helper macro to put the command
string into its own ELF section:
GUESTFSD_EXT_CMD(C_variable, command_name);
This syntax makes it still possible to grep for used command names.
The actual usage of the collected list could be like this:
objcopy -j .guestfsd_ext_cmds -O binary daemon/guestfsd /dev/stdout |
tr '\0' '\n' | sort -u
The resulting output will be used to tell mkinitrd which programs to
copy into the initrd.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
RWMJ:
- Move str_vgchange at request of author.
- Fix snprintf call in daemon/debug.c
In the libguestfs live case we need to be careful not to modify the
real /etc/lvm/lvm.conf file (when setting the filter rule).
When the daemon starts, make a complete copy of /etc/lvm in a
temporary directory, and adjust LVM_SYSTEM_DIR to point to the copy.
All changes are made in the temporary copy.
Remove some debug messages which were basically left over from when
the code was being developed.
However we leave debug messages where it is printing an external
command that is about to be executed, since those are useful.
These APIs allow you to change the device filter, the list of
block devices that LVM "sees". Either you can set it to a fixed
list of devices / partitions, or you can clear it so that LVM sees
everything.
