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Until now, when packing or unpacking a SquashFS image, files where
created with paranoid permissions (i.e. 0600). The rational behind
this was that otherwise, the tools may inadvertently expose secrets,
e.g. if a root user packs files that that aren't world readable,
such as the /etc/shadows file, but the packed SquashFS image is, we
have accidentally leaked this file to other users that can access
the newly created SquashFS image. The same line of reasoning also
applies when unpacking files.
Unfortunately, this breaks a list of other, more common standard use
cases (e.g. a build server where the an image is built by a deamon
running as user X but then has to be accessed by another deamon
running as Y).
This commit changes to a more standard approach of using permissive
file permissions by default and asking paranoid users to simply use
a paranoid umask.
For tar2sqfs & gensquashfs this simply means chaning the default
permissions in the libsquashfs file implementation.
For rdsquashfs on the other hand there is still the use case where
the unpacked files get the permissions from the [secret] image, so
setting a strict umask is not applicable and changing to permissive
file mode leaks something. For this case a second code path needs to
be added that derives the permissions from the ones in the image.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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I forgot to enable this when I copied it over from Mesa. Mesa's
meson configuration system checks that a C program using the uint128_t
type compiles, but I think this is likely unnecessary. Simply check the
macro that clang and gcc define.
This cuts the .text size of hash_table.o by 160 bytes or about 4% on my
system.
Signed-off-by: Matt Turner <mattst88@gmail.com>
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Not only does this build the hashtable into libutil.a, it also makes
sure the headers end up in the distribution tarball.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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With `perf record`/`perf report` I saw that 30% of the time was spent in
`sqfs_frag_table_find_tail_end` with tar2sqfs for a tarball containing
the Gentoo ebuild repository (many thousands of small files).
The reason was the bucketing hash table in frag_table.c: too many
elements in too few buckets meant lots of walking over the linked lists.
This patch replaces that hash table with the hash table implementation
from Mesa. Its implementation is more complex (is is an open-addressing,
linear-reprobing) hash table, but it is much better suited for the task.
On my 4c/8t Skylake, the time to run tar2sqfs drops from 7.5s to less
than 3s. CPU usage increases from ~207% to ~356%, presumably indicating
an increase in available parallelism due to the removal of the hash
table as a bottleneck. The `perf report` profile with this patch shows
that the time spent in `sqfs_frag_table_find_tail_end` has dropped from
~30% to 0.01%.
Output from ministat:
x before
+ after
N Min Max Median Avg Stddev
x 20 7.476 7.685 7.5725 7.5615 0.051254268
+ 20 2.79 2.901 2.846 2.84475 0.03543842
Difference at 95.0% confidence
-4.71675 +/- 0.0282015
-62.3785% +/- 0.241477%
(Student's t, pooled s = 0.0440618)
I imported only the bits of the hash table implementation that were
needed for frag_table.c. Among the changes I made after importing are
- removed usage of ralloc, Mesa's recursive memory allocator
- Replaced ralloc -> malloc
ralloc_free -> free
rzalloc_array -> calloc
- Removed mem_ctx parameters
- Added free()s to the appropriate places (valgrind confirms there
are no leaks)
- removed _mesa_-prefix from function names
Fixes: #40
Signed-off-by: Matt Turner <mattst88@gmail.com>
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Tar archives can contain set two kinds of PAX headers:
- local headers that modify the attributes of the next file
- global headers that set defaults for all files
The later is used "... not widely used", according to tar(5)
and has been deliberately not implemented.
Some programs (e.g. git-archive) *do* generate them (in the case
of git, it stores the commit hash).
This commit adds a code path that skips a PAX global header entirely
and resumes tar parsing, instead of erroneusly reporting it as an
entry.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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In libtar, the sizeof time_t checked when trying to store a time value.
It is pointless using the preprocessor here, as we can simply do an
if (sizeof(time_t) < ...) check and the compiler will take care
optimizing away one or the other branch.
After changing the libtar check and the corresponding unit tests, the
sizeof check can be removed from configure.ac, along with other unused
sizeof checks.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Simply moving the pax header decoding to a separate file and splitting
out the common helper functions should be a good start.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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This commit changes the tar2sqfs & gensquashfs code to pass the exit
status on to sqfs_writer_cleanup in libcommon.
The function sqfs writer code in libcommon is changed to retain the
output file name and delete it if the status passed to the cleanup
function is anything other than EXIT_SUCCESS.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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lib/common/compress.c: In function 'compressor_get_default':
lib/common/compress.c:39:2: warning: implicit declaration of function 'assert' [-Wimplicit-function-declaration]
39 | assert(0);
| ^~~~~~
lib/common/compress.c:8:1: note: 'assert' is defined in header '<assert.h>'; did you forget to '#include <assert.h>'?
7 | #include "common.h"
+++ |+#include <assert.h>
8 |
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Initialize have_compressor to false before testing, to make
the check work.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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This fixes a copy and paste error in the cleanup path, destroying a
previously destroyed object again instead of the one being tested for.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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On Linux, checking for > 0 worked because pthread_t is internally an
integer type. On other platforms (*caugh* Mac OS X *caugh*), it is
typedefed to an opaque pointer, causing a warning if used in an
integer relational comparison.
The intended use is to allow the generic cleanup function to be used
in the error path of the block processor creation function, while
preventing pthread_join being called on threads that haven't been
created at all. Since they are calloc'ed to 0, testing for non-zero
values should suffice in both cases.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Older versions of liblz4 don't define LZ4HC_CLEVEL_MAX. This commit
adds a definition if liblz4 doesn't provide one.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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The code was originally used inside the block processor, where 32 bit
aligned data could be guaranteed. If it is available in libutil, I
cannot possibly guarantee for alignment in future use elsewhere. Even
for the block processor it was rather risky "remember this detail very
well" buisness.
This commit restores the unaligned read treatment of the original.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Make sure the function has a way of telling the caller *why* it failed.
This way, the function can convey whether it had an internal error, an
allocation failure, whether the arguments are totaly nonsensical, or
simply that the compressor *or specific configuration* is not supported.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Avoid namespace polution. Make sure all exportet symbols are prefixed
with either sqfs_ or SQFS_.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Instead of creating everything in the "create" function, cleanup and
create/initialize stuff in a "load" function. This allows the xattr
reader to be reset/re-used and adds the benefit of not having to
lug around references to the super block, compressor and file (altough
the later two are hidden inside the meta reader).
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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This patch adds a deep-copy callback to sqfs_object_t and removes the
copying mechanism from sqfs_compressor_t. This is also interesting for
other types.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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On 32 bit systems, size_t is a 32 bit integer and doing 64 bit shifts
won't do us any good. So instead, use the existing size_t multiply and
catch overflow macros.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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This commit tries to untangle the logic of parsing and sanitizing the
pax header length field and the associated bounds checks.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Make sure the function throws an error if a given compressor ID or
flag is not known. This way, libsquahfs supports *exactly* and *only*
what the on-disk format specifies.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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This allows getting the compressor configuration back after
creating it, for various purposes.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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With unified payload size counters, copying an inode is now trivial.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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If the block processor allocates and dynamically resizes inodes on
the fly, we can add data indefinitely without knowing the size of
the file ahead of time.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Instead of having seperate counters for blocks, dir index bytes
and having to fiddle out the link target size, simply use a single
value that stores the number of payload bytes used.
A seperate "payload bytes available" is used for dynamically
growing inodes during processing.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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The file has to report the "apparent size" for sparse files, but
internally work with the actual size in the tar ball.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Since the merged destructor checks if the objects it destroys were
actually initialized, the pthread implementation can also replace
its error path cleanup with simply calling the destructor.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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This function waits for all pending blocks to be written to disk, but
doesn't flush the fragment block, so processing can continue afterwards
as if nothing happened.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Instead of doing a linear search, which scales quadratically, use a
red-black tree with inode numbers as key for finding hard links.
To reiterate: we can't just use a flat table, because the SquashFS
file is potentially untrusted and the inode numbers can be anything,
no matter what the super block says.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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This commit removes the allocation helpers and string table functions
out of libsquashfs back into a "libutil.a". The problem of libsquashfs
exporting stuff that it shouldn't is resolved by retaining the internal
attributes and directly adding the source to libsquashfs instead of
trying to somehow link against libutil.la.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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- Merge duplicated code from append_to_work_queue and
sqfs_block_processor_finish
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Implement the io-queue based design as outline in doc/parallelism.txt
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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- Split the worker function up into smaller functions that are
a little more readable.
- Only dequeue one block at a time. Makes the dequeueing a lot
more readable and understandable.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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On the one hand, benchmarking and profiling determined xxhash32 to be
faster than the zlib implementation of crc32, on the other hand
profiling determined that crc32 computation contributed signifficantly
to the overall runtime.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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This commit moves all of the fragment/block accounting in the block
processor over to the writing end of the pipeline. In order to do
this, the sparse blocks are allowed to bubble through the pipeline.
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
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