Commit Graph

1047 Commits

Author SHA1 Message Date
Jia Tan fd90e2f4c2 liblzma: Remove note from lzma_options_bcj about the ARM64 exception.
This was left in by mistake since an early version of the ARM64 filter
used a different struct for its options.
2023-03-17 01:42:28 +08:00
Jia Tan 55ba6e9300 liblzma: Add set lzma.h as the main page for Doxygen documentation.
The \mainpage command is used in the first block of comments in lzma.h.
This changes the previously nearly empty index.html to use the first
comment block in lzma.h for its contents.

lzma.h is no longer documented separately, but this is for the better
since lzma.h only defined a few macros that users do not need to use.
The individual API header files all have a disclaimer that they should
not be #included directly, so there should be no confusion on the fact
that lzma.h should be the only header used by applications.

Additionally, the note "See ../lzma.h for information about liblzma as
a whole." was removed since lzma.h is now the main page of the
generated HTML and does not have its own page anymore. So it would be
confusing in the HTML version and was only a "nice to have" when
browsing the source files.
2023-03-17 01:42:28 +08:00
Jia Tan af55191102 liblzma: Defines masks for return values from lzma_index_checks(). 2023-03-13 20:49:53 +08:00
Lasse Collin 717aa3651c xz: Simplify the error-label in Capsicum sandbox code.
Also remove unneeded "sandbox_allowed = false;" as this code
will never be run more than once (making it work with multiple
input files isn't trivial).
2023-03-11 18:46:45 +02:00
Lasse Collin a0eecc235d xz: Make Capsicum sandbox more strict with stdin and stdout. 2023-03-08 23:22:15 +08:00
Jia Tan 916448d624 Revert: "Add warning if Capsicum sandbox system calls are unsupported."
The warning causes the exit status to be 2, so this will cause problems
for many scripted use cases for xz. The sandbox usage is already very
limited already, so silently disabling this allows it to be more usable.
2023-03-08 23:22:11 +08:00
Jia Tan 01587dda2a xz: Fix -Wunused-label in io_sandbox_enter().
Thanks to Xin Li for recommending the fix.
2023-03-07 20:02:22 +08:00
Jia Tan 5fb9367866 xz: Add warning if Capsicum sandbox system calls are unsupported.
The warning is only used when errno == ENOSYS. Otherwise, xz still
issues a fatal error.
2023-03-06 21:37:45 +08:00
Jia Tan 61ee82cb12 xz: Skip Capsicum sandbox system calls when they are unsupported.
If a system has the Capsicum header files but does not actually
implement the system calls, then this would render xz unusable. Instead,
we can check if errno == ENOSYS and not issue a fatal error.
2023-03-06 21:27:53 +08:00
Jia Tan f070722b57 xz: Reorder cap_enter() to beginning of capsicum sandbox code.
cap_enter() puts the process into the sandbox. If later calls to
cap_rights_limit() fail, then the process can still have some extra
protections.
2023-03-06 21:08:26 +08:00
Jia Tan f1ab1f6b33 liblzma: Clarify lzma_lzma_preset() documentation in lzma12.h.
lzma_lzma_preset() does not guarentee that the lzma_options_lzma are
usable in an encoder even if it returns false (success). If liblzma
is built with default configurations, then the options will always be
usable. However if the match finders hc3, hc4, or bt4 are disabled, then
the options may not be usable depending on the preset level requested.

The documentation was updated to reflect this complexity, since this
behavior was unclear before.
2023-03-01 21:42:31 +08:00
Jia Tan 3cf72c4bcb liblzma: Replace '\n' -> newline in filter.h documentation.
The '\n' renders as a newline when the comments are converted to html
by Doxygen.
2023-02-24 21:09:39 +08:00
Jia Tan 002006be62 liblzma: Shorten return description for two functions in filter.h.
Shorten the description for lzma_raw_encoder_memusage() and
lzma_raw_decoder_memusage().
2023-02-24 21:09:39 +08:00
Jia Tan 463d9359b8 liblzma: Reword a few lines in filter.h 2023-02-24 21:09:39 +08:00
Jia Tan 01441df92c liblzma: Improve documentation in filter.h.
All functions now explicitly specify parameter and return values.
The notes and code annotations were moved before the parameter and
return value descriptions for consistency.

Also, the description above lzma_filter_encoder_is_supported() about
not being able to list available filters was removed since
lzma_str_list_filters() will do this.
2023-02-24 21:09:39 +08:00
Lasse Collin 30e95bb44c liblzma: Avoid null pointer + 0 (undefined behavior in C).
In the C99 and C17 standards, section 6.5.6 paragraph 8 means that
adding 0 to a null pointer is undefined behavior. As of writing,
"clang -fsanitize=undefined" (Clang 15) diagnoses this. However,
I'm not aware of any compiler that would take advantage of this
when optimizing (Clang 15 included). It's good to avoid this anyway
since compilers might some day infer that pointer arithmetic implies
that the pointer is not NULL. That is, the following foo() would then
unconditionally return 0, even for foo(NULL, 0):

    void bar(char *a, char *b);

    int foo(char *a, size_t n)
    {
        bar(a, a + n);
        return a == NULL;
    }

In contrast to C, C++ explicitly allows null pointer + 0. So if
the above is compiled as C++ then there is no undefined behavior
in the foo(NULL, 0) call.

To me it seems that changing the C standard would be the sane
thing to do (just add one sentence) as it would ensure that a huge
amount of old code won't break in the future. Based on web searches
it seems that a large number of codebases (where null pointer + 0
occurs) are being fixed instead to be future-proof in case compilers
will some day optimize based on it (like making the above foo(NULL, 0)
return 0) which in the worst case will cause security bugs.

Some projects don't plan to change it. For example, gnulib and thus
many GNU tools currently require that null pointer + 0 is defined:

    https://lists.gnu.org/archive/html/bug-gnulib/2021-11/msg00000.html

    https://www.gnu.org/software/gnulib/manual/html_node/Other-portability-assumptions.html

In XZ Utils null pointer + 0 issue should be fixed after this
commit. This adds a few if-statements and thus branches to avoid
null pointer + 0. These check for size > 0 instead of ptr != NULL
because this way bugs where size > 0 && ptr == NULL will likely
get caught quickly. None of them are in hot spots so it shouldn't
matter for performance.

A little less readable version would be replacing

    ptr + offset

with

    offset != 0 ? ptr + offset : ptr

or creating a macro for it:

    #define my_ptr_add(ptr, offset) \
            ((offset) != 0 ? ((ptr) + (offset)) : (ptr))

Checking for offset != 0 instead of ptr != NULL allows GCC >= 8.1,
Clang >= 7, and Clang-based ICX to optimize it to the very same code
as ptr + offset. That is, it won't create a branch. So for hot code
this could be a good solution to avoid null pointer + 0. Unfortunately
other compilers like ICC 2021 or MSVC 19.33 (VS2022) will create a
branch from my_ptr_add().

Thanks to Marcin Kowalczyk for reporting the problem:
https://github.com/tukaani-project/xz/issues/36
2023-02-23 20:41:22 +02:00
Jia Tan fa9065fac5 liblzma: Adjust container.h for consistency with filter.h. 2023-02-23 20:27:59 +08:00
Jia Tan 00a721b63d liblzma: Fix small typos and reword a few things in filter.h. 2023-02-23 20:27:59 +08:00
Jia Tan 5b1c171d4f liblzma: Convert list of flags in lzma_mt to bulleted list. 2023-02-23 20:27:59 +08:00
Jia Tan dbd47622eb liblzma: Fix typo in documentation in container.h
lzma_microlzma_decoder -> lzma_microlzma_encoder
2023-02-23 20:27:59 +08:00
Jia Tan 14cd30806d liblzma: Improve documentation for container.h
Standardizing each function to always specify parameters and return
values. Also moved the parameters and return values to the end of each
function description.
2023-02-23 20:27:59 +08:00
Lasse Collin d831072cce liblzma: Very minor API doc tweaks.
Use "member" to refer to struct members as that's the term used
by the C standard.

Use lzma_options_delta.dist and such in docs so that in Doxygen's
HTML output they will link to the doc of the struct member.

Clean up a few trailing white spaces too.
2023-02-16 21:09:00 +02:00
Jia Tan f029daea39 liblzma: Adjust spacing in doc headers in bcj.h. 2023-02-17 00:54:33 +08:00
Jia Tan a5de68bac2 liblzma: Adjust documentation in bcj.h for consistent style. 2023-02-17 00:49:47 +08:00
Jia Tan efa498c13b liblzma: Rename field => member in documentation.
Also adjusted preset value => preset level.
2023-02-17 00:49:47 +08:00
Lasse Collin 718b22a6c5 liblzma: Silence a warning from MSVC.
It gives C4146 here since unary minus with unsigned integer
is still unsigned (which is the intention here). Doing it
with substraction makes it clearer and avoids the warning.

Thanks to Nathan Moinvaziri for reporting this.
2023-02-16 17:59:50 +02:00
Jia Tan 87c53553fa liblzma: Improve documentation for stream_flags.h
Standardizing each function to always specify parameters and return
values. Also moved the parameters and return values to the end of each
function description.

A few small things were reworded and long sentences broken up.
2023-02-16 21:04:54 +08:00
Jia Tan 13d99e75a5 liblzma: Improve documentation in lzma12.h.
All functions now explicitly specify parameter and return values.
2023-02-15 22:21:44 +08:00
Jia Tan 43ec344c86 liblzma: Improve documentation in check.h.
All functions now explicitly specify parameter and return values.
Also moved the note about SHA-256 functions not being exported to the
top of the file.
2023-02-15 00:59:16 +08:00
Jia Tan 9c71db4e88 liblzma: Improve documentation in index.h
All functions now explicitly specify parameter and return values.
2023-02-15 00:20:44 +08:00
Jia Tan 421f2f2e16 liblzma: Reword a comment in index.h. 2023-02-15 00:20:44 +08:00
Jia Tan b675394849 liblzma: Omit lzma_index_iter's internal field from Doxygen docs.
Add \private above this field and its sub-fields since it is not meant
to be modified by users.
2023-02-15 00:20:44 +08:00
Jia Tan 0c9e4fc2ad liblzma: Fix documentation for LZMA_MEMLIMIT_ERROR.
LZMA_MEMLIMIT_ERROR was missing the "<" character needed to put
documentation after a member.
2023-02-14 20:41:05 +08:00
Jia Tan 816fec125a liblzma: Improve documentation for base.h.
Standardizing each function to always specify params and return values.
Also fixed a small grammar mistake.
2023-02-14 20:41:05 +08:00
Jia Tan 862dacef1a liblzma: Add one more missing [out] annotation in vli.h 2023-02-14 00:12:34 +08:00
Jia Tan 867b08ae42 liblzma: Minor improvements to vli.h.
Added [out] annotations to parameters that are pointers and can have
their value changed. Also added a clarification to lzma_vli_is_valid.
2023-02-14 00:08:33 +08:00
Jia Tan 90d0e628ff liblzma: Add comments for macros in delta.h.
Document LZMA_DELTA_DIST_MIN and LZMA_DELTA_DIST_MAX for completeness
and to avoid Doxygen warnings.
2023-02-10 21:38:25 +08:00
Jia Tan 9255fffdb1 liblzma: Improve documentation in index_hash.h.
All functions now explicitly specify parameter and return values.
Also reworded the description of lzma_index_hash_init() for readability.
2023-02-10 21:35:23 +08:00
Lasse Collin 1dbe12b90c xz: Improve the comment about start_time in mytime.c.
start_time is relative to an arbitary point in time, it's not
time of day, so using it for anything else than time differences
wouldn't make sense.
2023-02-07 19:07:45 +02:00
Jia Tan b8bce89be7 xz: Add a comment clarifying the use of start_time in mytime.c. 2023-02-04 20:11:51 +08:00
Jia Tan 912af91b10 liblzma: Improve documentation for version.h.
Specified parameter and return values for API functions and documented
a few more of the macros.
2023-02-04 20:11:36 +08:00
Jia Tan 2c78a83c6f liblzma: Fix bug in lzma_str_from_filters() not checking filters[] length.
The bug is only a problem in applications that do not properly terminate
the filters[] array with LZMA_VLI_UNKNOWN or have more than
LZMA_FILTERS_MAX filters. This bug does not affect xz.
2023-02-03 00:42:27 +08:00
Jia Tan 8dfc029e7a liblzma: Fix typos in comments in string_conversion.c. 2023-02-03 00:42:27 +08:00
Jia Tan 54ad83c1ae liblzma: Clarify block encoder and decoder documentation.
Added a few sentences to the description for lzma_block_encoder() and
lzma_block_decoder() to highlight that the Block Header must be coded
before calling these functions.
2023-02-03 00:22:53 +08:00
Jia Tan f680e771b3 Update lzma_block documentation for lzma_block_uncomp_encode(). 2023-02-03 00:22:53 +08:00
Jia Tan 504cf4af89 liblzma: Minor edits to lzma_block header_size documentation. 2023-02-03 00:22:53 +08:00
Jia Tan 115b720fb5 liblzma: Enumerate functions that read version in lzma_block. 2023-02-03 00:22:53 +08:00
Jia Tan 85ea0979ad liblzma: Clarify comment in block.h. 2023-02-03 00:22:53 +08:00
Jia Tan 1f7ab90d9c liblzma: Improve documentation for block.h.
Standardizing each function to always specify params and return values.
Output pointer parameters are also marked with doxygen style [out] to
make it clear. Any note sections were also moved above the parameter and
return sections for consistency.
2023-02-03 00:22:53 +08:00
Jia Tan c563a4bc55 liblzma: Clarify a comment about LZMA_STR_NO_VALIDATION.
The flag description for LZMA_STR_NO_VALIDATION was previously confusing
about the treatment for filters than cannot be used with .xz format
(lzma1) without using LZMA_STR_ALL_FILTERS. Now, it is clear that
LZMA_STR_NO_VALIDATION is not a super set of LZMA_STR_ALL_FILTERS.
2023-02-01 23:39:45 +08:00