Useful for debugging problems caused by the host kernel. In
particular we were looking at a problem with passt creating a user
namespace but didn't know what exact kernel was being used.
Consider the following inverted call tree (effectively a dependency tree
-- callees are at the top and near the left margin):
lazy_make_tmpdir() [lib/tmpdirs.c]
guestfs_int_lazy_make_tmpdir() [lib/tmpdirs.c]
guestfs_int_make_temp_path() [lib/tmpdirs.c]
guestfs_int_lazy_make_sockdir() [lib/tmpdirs.c]
guestfs_int_create_socketname() [lib/launch.c]
lazy_make_tmpdir() is our common workhorse / helper function that
centralizes the mkdtemp() function call.
guestfs_int_lazy_make_tmpdir() and guestfs_int_lazy_make_sockdir() are the
next level functions, both calling lazy_make_tmpdir(), just feeding it
different dirname generator functions, and different "is_runtime_dir"
qualifications. These functions create temp dirs for various, more
specific, purposes (see the manual and "lib/guestfs-internal.h" for more
details).
On a yet higher level are guestfs_int_make_temp_path() and
guestfs_int_create_socketname() -- they serve for creating *entries* in
those specific temp directories.
The discrepancy here is that, although all the other functions live in
"lib/tmpdirs.c", guestfs_int_create_socketname() is defined in
"lib/launch.c". That makes for a confusing code reading; move the function
to "lib/tmpdirs.c", just below its sibling function
guestfs_int_make_temp_path().
While at it, correct the leading comment on
guestfs_int_create_socketname() -- the socket pathname is created in the
socket directory, not in the temporary directory.
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2184967
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
Message-Id: <20230714132213.96616-6-lersek@redhat.com>
We generate the <interface type="user"> element on libvirt 3.8.0+ already.
For selecting passt rather than SLIRP, we only need to insert the child
element <backend type='passt'>. Make that child element conditional on
libvirt 9.0.0+, plus "passt --help" being executable.
For the latter, place the new helper function guestfs_int_passt_runnable()
in "lib/launch.c" -- we're going to use the same function for the direct
backend as well.
This change exposes a number of (perceived) shortcomings in libvirt; I've
filed <https://bugzilla.redhat.com/show_bug.cgi?id=2222766> about those.
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2184967
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
Message-Id: <20230714132213.96616-3-lersek@redhat.com>
We require libvirt >= 0.10.2, and we included code to check this at
configure-, compile- and run-time. Remove the checks at compile and
run time (keep the ./configure check). Libvirt 0.10.2 was released
over 10 years ago so it's safe to assume that everyone has it by now.
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').
launch.c:191:3: error: implicit declaration of function 'sigemptyset' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
sigemptyset (&sigset);
^
launch.c:192:3: error: implicit declaration of function 'sigaddset' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
sigaddset (&sigset, SIGTERM);
^
launch.c:193:3: error: implicit declaration of function 'sigprocmask' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
sigprocmask (SIG_UNBLOCK, &sigset, NULL);
^
3 errors generated.
These were added in libguestfs 1.14, but never really used. Only a
handful of probes were available. When I was benchmarking libguestfs
in 2016 I didn't even use these probes because better/simpler
techniques were available.
User-Mode Linux was an alternative hypervisor that could run the
appliance, instead of using qemu. It had many limitations including
lack of network, and UML support in Linux has been semi-broken for a
long time. It was also slower than KVM on baremeal in general and had
various corner cases which were much slower including the emulated
serial port which made bulk uploads and downloads painful. Also of
course it lacked qemu-specific features like qcow2 or any
network-backed disk, so many disk images could not be opened this way.
This was never supported in RHEL.
See-also: https://bugzilla.redhat.com/1144197
This experimental feature allowed you (in theory) to connect to an
existing instance of the libguestfs daemon. (Again, in theory) it
allowed you to attach to running guests. This didn't work well in
practice. If you want to do this, install qemu-guest-agent inside
your guest instead.
This also disables the --live options in guestfish and guestmount.
(The option now prints an error).
This was never supported in RHEL.
The daemon tests relied on this connection method to perform tests on
a bare daemon, so this removes those tests. They were not especially
valuable.
See-also: https://bugzilla.redhat.com/798980
GCC 12 gives a warning about our previous attempt to check the length
of the socket path. In the ensuing discussion it was pointed out that
it is easier to get snprintf to do the hard work. snprintf will
return an int >= UNIX_PATH_MAX if the path is too long, or < 0 if
there are other errors such as locale/encoding problems. So we should
just check for those two cases instead.
https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/NPKWMTSJ2A2ABNJJEH6WTZIAEFTX6CQY/
Thanks: Martin Sebor and Laszlo Ersek
In particular the virt-rescue --scratch option makes it very easy to
add huge numbers of drives. Since the per-backend max_disks limit was
never checked anywhere you could get peculiar failures. Now you'll
get a clear error message:
$ virt-rescue --scratch=256
libguestfs: error: too many drives have been added, the current backend only supports 255 drives
Only in end-user messages and documentation. This change was done
mostly mechanically using the Perl script attached below.
I also changed don't -> don’t etc and made some other simple fixes.
See also: https://www.cl.cam.ac.uk/~mgk25/ucs/quotes.html
----------
#!/usr/bin/perl -w
use strict;
use Locale::PO;
my $re = qr{'([-\w%.,=?*/]+)'};
my %files = ();
foreach my $filename ("po/libguestfs.pot", "po-docs/libguestfs-docs.pot") {
my $poref = Locale::PO->load_file_asarray($filename);
foreach my $po (@$poref) {
if ($po->msgid =~ $re) {
my @refs = split /\s+/, $po->reference;
foreach my $ref (@refs) {
my ($file, $lineno) = split /:/, $ref, 2;
$file =~ s{^\.\./}{};
if (exists $files{$file}) {
push @{$files{$file}}, $lineno;
} else {
$files{$file} = [$lineno];
}
}
}
}
}
foreach my $file (sort keys %files) {
unless (-w $file) {
warn "warning: $file is probably generated\n"; # have to edit generator
next;
}
my @lines = sort { $a <=> $b } @{$files{$file}};
#print "editing $file at lines ", join (", ", @lines), " ...\n";
open FILE, "<$file" or die "$file: $!";
my @all = ();
push @all, $_ while <FILE>;
close FILE;
my $ext = $file;
$ext =~ s/^.*\.//;
foreach (@lines) {
# Don't mess with verbatim sections in POD files.
next if $ext eq "pod" && $all[$_-1] =~ m/^ /;
unless ($all[$_-1] =~ $re) {
# this can happen for multi-line strings, have to edit it
# by hand
warn "warning: $file:$_ does not contain expected content\n";
next;
}
$all[$_-1] =~ s/$re/‘$1’/g;
}
rename "$file", "$file.bak";
open FILE, ">$file" or die "$file: $!";
print FILE $_ for @all;
close FILE;
my $mode = (stat ("$file.bak"))[2];
chmod ($mode & 0777, "$file");
}
