We mentioned eventual dropping of libcrypt in the 2.28 NEWS. Actually
put that plan in motion by first disabling building libcrypt by default.
note in NEWS that the library will be dropped completely in a future
release.
Also add a couple of builds into build-many-glibcs.py.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Andreas K. Hüttel <dilfridge@gentoo.org>
Bump autoconf requirement to 2.71 to allow regenerating configure on
more recent distributions. autoconf 2.71 has been in Fedora since F36
and is the current version in Debian stable (bookworm). It appears to
be current in Gentoo as well.
All sysdeps configure and preconfigure scripts have also been
regenerated; all changes are trivial transformations that do not affect
functionality.
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Add --enable-fortify-source option.
It is now possible to enable fortification through a configure option.
The level may be given as parameter, if none is provided, the configure
script will determine what is the highest level possible that can be set
considering GCC built-ins availability and set it.
If level is explicitly set to 3, configure checks if the compiler
supports the built-in function necessary for it or raise an error if it
isn't.
If the configure option isn't explicitly enabled, it _FORTIFY_SOURCE is
forcibly undefined (and therefore disabled).
The result of the configure checks are new variables, ${fortify_source}
and ${no_fortify_source} that can be used to appropriately populate
CFLAGS.
A dedicated patch will follow to make use of this variable in Makefiles
when necessary.
Updated NEWS and INSTALL.
Adding dedicated x86_64 variant that enables the configuration.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
The current implementation of strerror is thread-safe, but this
has implications for the lifetime of the return string.
Describe the strerror_l function. Describe both variants of the
strerror_r function. Mention the lifetime of the returned string
for strerrorname_np and strerrordesc_np. Clarify that perror
output depends on the current locale.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Describe the problems with signed characters, and the glibc extension
to deal with most of them. Mention that the is* functions return
zero for the special argument EOF.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
In documentation, call strings like "CST" time zone abbreviations, not
time zone names. This terminology is more precise, and is what tzdb uses.
A string like "CST" is ambiguous and does not fully name a time zone.
ISO C2x defines scanf %b for input of binary integers (with an
optional 0b or 0B prefix). Implement such support, along with the
corresponding SCNb* macros in <inttypes.h>. Unlike the support for
binary integers with 0b or 0B prefix with scanf %i, this is supported
in all versions of scanf (independent of the standards mode used for
compilation), because there are no backwards compatibility concerns
(%b wasn't previously a supported format) the way there were for %i.
Tested for x86_64 and x86.
ISO C2x defines printf length modifiers wN (for intN_t / int_leastN_t
/ uintN_t / uint_leastN_t) and wfN (for int_fastN_t / uint_fastN_t).
Add support for those length modifiers (such a feature was previously
requested in bug 24466). scanf support is to be added separately.
GCC 13 has format checking support for these modifiers.
When used with the support for registering format specifiers, these
modifiers are translated to existing flags in struct printf_info,
rather than trying to add some way of distinguishing them without
breaking the printf_info ABI. C2x requires an error to be returned
for unsupported values of N; this is implemented for printf-family
functions, but the parse_printf_format interface doesn't support error
returns, so such an error gets discarded by that function.
Tested for x86_64 and x86.
This patch adds the strict checking for power-of-two alignments
in aligned_alloc(), and updates the manual accordingly.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The argument to @deftypefun must be on a single line.
Also add the missing @safety for sem_clockwait.
Reported-by: Nilgün Belma Bugüner <nillguine@gmail.com>
This patch enables libmvec on AArch64. The proposed change is mainly
implementing build infrastructure to add the new routines to ABI,
tests and benchmarks. I have demonstrated how this all fits together
by adding implementations for vector cos, in both single and double
precision, targeting both Advanced SIMD and SVE.
The implementations of the routines themselves are just loops over the
scalar routine from libm for now, as we are more concerned with
getting the plumbing right at this point. We plan to contribute vector
routines from the Arm Optimized Routines repo that are compliant with
requirements described in the libmvec wiki.
Building libmvec requires minimum GCC 10 for SVE ACLE. To avoid raising
the minimum GCC by such a big jump, we allow users to disable libmvec
if their compiler is too old.
Note that at this point users have to manually call the vector math
functions. This seems to be acceptable to some downstream users.
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
In some cases, we do not want to go through the resolver for function
calls. For example, functions with vector arguments will use vector
registers to pass arguments. In the resolver, we do not save/restore the
vector argument registers for lazy binding efficiency. To avoid ruining
the vector arguments, functions with vector arguments will not go
through the resolver.
To achieve the goal, we will annotate the function symbols with
STO_RISCV_VARIANT_CC flag and add DT_RISCV_VARIANT_CC tag in the dynamic
section. In the first pass on PLT relocations, we do not set up to call
_dl_runtime_resolve. Instead, we resolve the functions directly.
Signed-off-by: Hsiangkai Wang <kai.wang@sifive.com>
Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://inbox.sourceware.org/libc-alpha/20230314162512.35802-1-kito.cheng@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
State that getpt is similar to posix_openpt. Use posix_openpt
instead of getpt in example.
Signed-off-by: Gavin Smith <gavinsmith0123@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Created tunable glibc.pthread.stack_hugetlb to control when hugepages
can be used for stack allocation.
In case THP are enabled and glibc.pthread.stack_hugetlb is set to
0, glibc will madvise the kernel not to use allow hugepages for stack
allocations.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* manual/string.texi (Truncating Strings): Update obsolescent
reference and use the more-generic term “AddressSanitizer”.
Mention fortification, too. -fcheck-pointer-bounds is no longer
supported.
* manual/string.texi: Editorial fixes. Do not say “text” when
“string” or “string contents” is meant, as a C string can contain
bytes that are not valid text in the current encoding.
When warning about strcat efficiency, warn similarly about strncat
and wcscat. “coping” → “copying”.
Mention at the start of the two problematic sections that problems
are discussed at section end.
The __warn_unused_result__ attribute is only enabled when fortification
is enabled. Mention that in the document. The rationale for this is
essentially to mitigate against CWE-252:
[1] https://cwe.mitre.org/data/definitions/252.html
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
And make always supported. The configure option was added on glibc 2.25
and some features require it (such as hwcap mask, huge pages support, and
lock elisition tuning). It also simplifies the build permutations.
Changes from v1:
* Remove glibc.rtld.dynamic_sort changes, it is orthogonal and needs
more discussion.
* Cleanup more code.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
It is the default since 2.26 and it has bitrotten over the years,
By using it multiple malloc tests fails:
FAIL: malloc/tst-memalign-2
FAIL: malloc/tst-memalign-2-malloc-hugetlb1
FAIL: malloc/tst-memalign-2-malloc-hugetlb2
FAIL: malloc/tst-memalign-2-mcheck
FAIL: malloc/tst-mxfast-malloc-hugetlb1
FAIL: malloc/tst-mxfast-malloc-hugetlb2
FAIL: malloc/tst-tcfree2
FAIL: malloc/tst-tcfree2-malloc-hugetlb1
FAIL: malloc/tst-tcfree2-malloc-hugetlb2
Checked on x86_64-linux-gnu.
Reviewed-by: DJ Delorie <dj@redhat.com>
Now that there is no need to use a special linker script to hardening
internal data structures, remove the --with-default-link configure
option and associated definitions.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
WG14 recently accepted two additions to the printf/scanf %b/%B
support: there are now PRIb* and SCNb* macros in <inttypes.h>, and
printf %B is now an optional feature defined in normative text,
instead of recommended practice, with corresponding PRIB* macros that
can also be used to test whether that optional feature is supported.
See N3072 items 14 and 15 for details (those changes were accepted,
some other changes in that paper weren't).
Add the corresponding PRI* macros to glibc and update one place in the
manual referring to %B as recommended. (SCNb* should naturally be
added at the same time as the corresponding scanf %b support.)
Tested for x86_64 and x86.
C2x adds binary integer constants starting with 0b or 0B, and supports
those constants for the %i scanf format (in addition to the %b format,
which isn't yet implemented for scanf in glibc). Implement that scanf
support for glibc.
As with the strtol support, this is incompatible with previous C
standard versions, in that such an input string starting with 0b or 0B
was previously required to be parsed as 0 (with the rest of the input
potentially matching subsequent parts of the scanf format string).
Thus this patch adds 12 new __isoc23_* functions per long double
format (12, 24 or 36 depending on how many long double formats the
glibc configuration supports), with appropriate header redirection
support (generally very closely following that for the __isoc99_*
scanf functions - note that __GLIBC_USE (DEPRECATED_SCANF) takes
precedence over __GLIBC_USE (C2X_STRTOL), so the case of GNU
extensions to C89 continues to get old-style GNU %a and does not get
this new feature). The function names would remain as __isoc23_* even
if C2x ends up published in 2024 rather than 2023.
When scanf %b support is added, I think it will be appropriate for all
versions of scanf to follow C2x rules for inputs to the %b format
(given that there are no compatibility concerns for a new format).
Tested for x86_64 (full glibc testsuite). The first version was also
tested for powerpc (32-bit) and powerpc64le (stdio-common/ and wcsmbs/
tests), and with build-many-glibcs.py.
Crossing 2GB boundaries with indirect calls and jumps can use more
branch prediction resources on Intel Golden Cove CPU (see the
"Misprediction for Branches >2GB" section in Intel 64 and IA-32
Architectures Optimization Reference Manual.) There is visible
performance improvement on workloads with many PLT calls when executable
and shared libraries are mmapped below 2GB. Add the Prefer_MAP_32BIT_EXEC
bit so that mmap will try to map executable or denywrite pages in shared
libraries with MAP_32BIT first.
NB: Prefer_MAP_32BIT_EXEC reduces bits available for address space
layout randomization (ASLR), which is always disabled for SUID programs
and can only be enabled by the tunable, glibc.cpu.prefer_map_32bit_exec,
or the environment variable, LD_PREFER_MAP_32BIT_EXEC. This works only
between shared libraries or between shared libraries and executables with
addresses below 2GB. PIEs are usually loaded at a random address above
4GB by the kernel.
