Add a new optional boolean argument 'keepdirlink' to tar_in that passes
--keep-directory-symlink to tar. This preserves existing symlinks to
directories when extracting, which is important for usrmerge systems
where /lib is a symlink to /usr/lib.
Without this option, extracting a tarball containing lib/modules/...
to / would replace the /lib symlink with a real directory, breaking
the system.
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
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').
We have traditionally used custom printf formatters %Q and %R, where
%Q replaces the argument with a shell-quoted string, and %R replaces
the argument with a sysroot-prefixed shell-quoted string. They are
actually pretty useful, but unfortunately only supported by glibc.
We only used them in about a dozen places in the daemon (much code
having been replaced by OCaml which does not need them).
In every remaining case we were constructing a command using code like
this:
asprintf_nowarn (&cmd,
"cd %Q && find -print0 | %s -0 -o -H %s --quiet", ...);
We can replace this with:
char *cmd;
size_t cmd_size;
fp = open_memstream (&cmd, &cmd_size);
fprintf (fp, "cd ");
shell_quote (dir, fp);
fprintf (fp, " && find -print0 | %s -0 -o -H %s --quiet", ...);
fclose (fp);
Current GNU tar does not restore all extended attributes. In
particular only user.* capabilities are restored (although all
are saved in the tarball).
To restore capabilities, SELinux security attributes, and other things
we need to use --xattrs-include=*
For further information on the tar bug, see:
https://bugzilla.redhat.com/show_bug.cgi?id=771927
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.
It will be useful also for APIs different than tar-out, so move it to
guestfsd.c, and add it a parameter to specify the function name that
invoked it.
This is mostly code motion.
Run the following command over the source:
perl -pi.bak -e 's/(20[01][0-9])-2016/$1-2017/g' `git ls-files`
(Thanks Rich for the perl snippet, as used in past years.)
Wherever we had code which did:
if (something_bad) {
perror (...);
exit (EXIT_FAILURE);
}
replace this with use of the error(3) function:
if (something_bad)
error (EXIT_FAILURE, errno, ...);
The error(3) function is supplied by glibc, or by gnulib on platforms
which don't have it, and is much more flexible than perror(3). Since
we already use error(3), there seems to be no downside to mandating it
everywhere.
Note there is one nasty catch with error(3): error (EXIT_SUCCESS, ...)
does *not* exit! This is also the reason why error(3) cannot be
marked as __attribute__((noreturn)).
Because the examples can't use gnulib, I did not change them.
To search for multiline patterns of the above form, pcregrep -M turns
out to be very useful:
pcregrep --buffer-size 10M -M '\bperror\b.*\n.*\bexit\b' `git ls-files`
GCC has two warnings related to large stack frames. We were already
using the -Wframe-larger-than warning, but this reduces the threshold
from 10000 to 5000 bytes.
However that warning only covers the static part of frames (not
alloca). So this change also enables -Wstack-usage=10000 which covers
both the static and dynamic usage (alloca and variable length arrays).
Multiple changes are made throughout the code to reduce frames to fit
within these new limits.
Note that stack allocation of large strings can be a security issue.
For example, we had code like:
size_t len = strlen (fs->windows_systemroot) + 64;
char software[len];
snprintf (software, len, "%s/system32/config/software",
fs->windows_systemroot);
where fs->windows_systemroot is guest controlled. It's not clear what
the effects might be of allowing the guest to allocate potentially
very large stack frames, but at best it allows the guest to cause
libguestfs to segfault. It turns out we are very lucky that
fs->windows_systemroot cannot be set arbitrarily large (see checks in
is_systemroot).
This commit changes those to large heap allocations instead.
Commit 864ef706a8 (in Aug 2012) broke
the deprecated txz-out API. Because of a thinko during this commit,
instead of producing xz files it produces bzip2 files.
Fix this API again.
Thanks: Bo Fan / Red Hat QA team.
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.
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
The compress flag can be used to control compression, one of: (none),
"compress", "gzip", "bzip2", "xz", "lzop". Thus these calls can now
be used instead of tgz-in/tgz-out/txz-in/txz-out, and also support
more compression types.
Mark these APIs as once_had_no_optargs so that compatibility code is
generated.
When using tar-in or tools built around it such as virt-make-fs, if
the target filesystem is vfat then unpacking the tarball would fail
because tar tries to chown(2) files and fails.
You would see errors such as:
tar: <file>: Cannot change ownership to uid 500, gid 500: Operation not permitted
This change detects whether the target filesystem supports chown(2).
If not, it adds the --no-same-owner flag to tar to stop it from trying
to change the ownership of newly created files.
Although this doesn't matter for the ordinary (appliance) case, it
matters for the libguestfs live case. In that case it could cause the
guest to be exploited by a tmp/symlink attack.
In the case where both ends cancel at the same time (eg. both ends
realize there are errors before or during the transfer), previously we
skipped sending back an error from the daemon, on the spurious basis
that the library would not need it (the library is cancelling because
of its own error).
However this is wrong: we should always send back an error message
from the daemon in order to preserve synchronization of the protocol.
A simple test case is:
$ guestfish -N fs -m /dev/sda1 upload nosuchfile /
libguestfs: error: open: nosuchfile: No such file or directory
libguestfs: error: unexpected procedure number (66/282)
(Notice two things: there are errors at both ends, and the
loss of synchronization).
After applying this commit, the loss of synchronization does not occur
and we just see the library error:
$ guestfish -N fs -m /dev/sda1 upload nosuchfile /
libguestfs: error: open: nosuchfile: No such file or directory
The choice of displaying the library or the daemon error is fairly
arbitrary in this case -- it would be valid to display either or even
to combine them into one error. Displaying the library error only
makes the code considerably simpler.
This commit also (re-)enables a test for this case.
As a previous, incorrect attempt to fix RHBZ#576879 we tried to
prevent the daemon from sending an error reply if the daemon had
cancelled the transfer. This is wrong: the daemon should send an
error reply in these cases.
A simple test case is this:
guestfish -N fs -m /dev/sda1 upload big-file /
(This fails because the target "/" is a directory, not a file.)
Prior to this commit, libguestfs would hang instead of printing an
error. With this commit, libguestfs prints an error.
What is happening is:
(1) Library is uploading
a file (2) In the middle of the long
upload, daemon detects an error.
Daemon cancels.
(3) Library detects cancel,
sends cancel chunk, then waits
for the error reply from the
daemon. (4) Daemon is supposed to send
an error reply message.
Because step (4) wasn't happening, uploads that failed like this would
hang in the library (waiting for the error message, while the daemon
was waiting for the next request).
This also adds a regression test.
This temporarily breaks the "both ends cancel" case (RHBZ#576879c5).
Therefore the test for that is disabled, and this is fixed in the next
patch in the series.
This partially reverts commit dc706a639e.
On Ubuntu <= Karmic, xz-utils was not packaged, and therefore
any xz-related tests would fail. Thus make this an optional
group so that we can test for this and avoid running the tests
if xz utils are not present.
This commit improves the error messages from the tar-in, tgz-in (etc)
commands by capturing the stderr from the tar command in a file and
sending that back in the error message.
The method used for the error file is primitive, and there is a case
for a more generic error file mechanism, but this will do for now.
Sample error messages after this change:
$ virt-tar -u /tmp/test1.img /tmp/not.tar /
tar_in: tar subcommand failed on directory: /: tar: This does not look like a tar archive
tar: Skipping to next header
tar: Exiting with failure status due to previous errors at /home/rjones/d/libguestfs/tools/virt-tar line 247.
$ virt-tar -u /tmp/test1.img /tmp/test.tar /
tar_in: tar subcommand failed on directory: /: tar: access.log: Cannot open: Read-only file system
tar: Exiting with failure status due to previous errors at /home/rjones/d/libguestfs/tools/virt-tar line 247.
During a FileIn command (eg. upload, tar-in) if both sides
experience errors, then both sides could send cancel messages,
the result being lost synchronization.
The reason for the lost synch was because the daemon was ignoring
this case and sending an error message back which the library side
(which had cancelled) was not expecting.
Fix this by checking in the daemon for the case where the library
also cancels during daemon cancellation, and not sending an error
messages.
This also includes an enhanced regression test which checks for this
case.
This extends the original fix in
commit 5922d7084d.
More details can be found here:
https://bugzilla.redhat.com/show_bug.cgi?id=576879#c5
Modify the generator so that it can correctly handle early
cancellation for Pathname|Device|.. parameters. This fixes
the upload command, but consequently we need to fix the
parameters for tar_in and t?z_in commands. This should also
mean that 'win:' can now be used as the second argument of
tar_in and t?z_in commands in guestfish, whereas previously
this wouldn't have worked.
Adds a regression test for the original problem.
