squashfs-tools-ng.git/lib/sqfs, branch v0.9.1

Fix: use 0644 as default permissions when creating files

2020-05-02T23:43:11+00:00

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

Import and use Mesa's hash table

2020-04-22T12:48:46+00:00

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

Fix destruction of NULL pointer in xattr reader cleanup

2020-03-19T22:06:24+00:00

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

Fix pthread_join check for valid thread handles

2020-03-19T01:04:28+00:00

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

Fix build of lz4 compressor with older versions of liblz4

2020-03-18T21:30:17+00:00

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

Cleanup: Move xxhash32 code to libutil

2020-03-18T12:33:47+00:00

Signed-off-by: David Oberhollenzer

Get rid of sqfs_compressor_exists

2020-03-05T21:55:09+00:00

Signed-off-by: David Oberhollenzer

Change the signature of sqfs_compressor_create to return an error code

2020-03-05T21:41:04+00:00

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

Cleanup: Remove the E_ prefix from all libsquashfs enumerators

2020-03-05T14:17:45+00:00

Avoid namespace polution. Make sure all exportet symbols are prefixed with either sqfs_ or SQFS_. Signed-off-by: David Oberhollenzer

Fix block writer inheritance of sqfs_object_t

2020-03-04T14:00:12+00:00

Signed-off-by: David Oberhollenzer