Exporting functions and relying on symbol interposition from libc.so
makes the choice of implementation dependent on DT_NEEDED order, which
is not what some compiler drivers expect.
This commit replaces one magic mechanism (symbol interposition) with
another one (preprocessor-/compiler-based redirection). This makes
the hand-over from the minimal malloc to the full malloc more
explicit.
Removing the ABI symbols is backwards-compatible because libc.so is
always in scope, and the dynamic loader will find the malloc-related
symbols there since commit f0b2132b35
("ld.so: Support moving versioned symbols between sonames
[BZ #24741]").
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
elf/dl-minimal.c provides a definition of free, so the function
pointer is always non-null, even before the final relocation
of the loader.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
The definitions are moved into a new file, elf/dl-sym-post.h, so that
this code can be used by the dynamic loader as well.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This generalizes a mechanism used for stack-protector support, so
that it can be applied to other symbols if required.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
With all Linux ABIs using the expected Linux kABI to indicate
syscalls errors, the INTERNAL_SYSCALL_DECL is an empty declaration
on all ports.
This patch removes the 'err' argument on INTERNAL_SYSCALL* macro
and remove the INTERNAL_SYSCALL_DECL usage.
Checked with a build against all affected ABIs.
With all Linux ABIs using the expected Linux kABI to indicate
syscalls errors, there is no need to replicate the INLINE_SYSCALL.
The generic Linux sysdep.h includes errno.h even for !__ASSEMBLER__,
which is ok now and it allows cleanup some archaic code that assume
otherwise.
Checked with a build against all affected ABIs.
The riscv INTERNAL_SYSCALL macro might clobber the register
parameter if the argument itself might clobber any register (a function
call for instance).
This patch fixes it by using temporary variables for the expressions
between the register assignments (as indicated by GCC documentation,
6.47.5.2 Specifying Registers for Local Variables).
It is similar to the fix done for MIPS (bug 25523).
Checked with riscv64-linux-gnu-rv64imafdc-lp64d build.
The microblaze INTERNAL_SYSCALL macro might clobber the register
parameter if the argument itself might clobber any register (a function
call for instance).
This patch fixes it by using temporary variables for the expressions
between the register assignments (as indicated by GCC documentation,
6.47.5.2 Specifying Registers for Local Variables).
It is similar to the fix done for MIPS (bug 25523).
Checked with microblaze-linux-gnu and microblazeel-linux-gnu build.
It changes the nios INTERNAL_SYSCALL_RAW macro to return a negative
value instead of the 'r2' register value on the 'err' macro argument.
The macro INTERNAL_SYSCALL_DECL is no longer required, and the
INTERNAL_SYSCALL_ERROR_P macro follows the other Linux kABIs.
Checked with a build against nios2-linux-gnu.
It changes the mips INTERNAL_SYSCALL* and internal_syscall* macros
to return a negative value instead of the 'a3' register value on then
'err' macro argument.
The macro INTERNAL_SYSCALL_DECL is no longer required, and the
INTERNAL_SYSCALL_ERROR_P macro follows the other Linux kABIs.
The redefinition of INTERNAL_VSYSCALL_CALL is also no longer
required.
Checked on mips64-linux-gnu, mips64n32-linux-gnu, and mips-linux-gnu.
The mips64 Linux syscall macros only differs argument type and
the requirement of sign-extending values on n32. The headers
are consolidate by parameterizing the arguments with a new type,
__syscall_arg_t, and by defining the ARGIFY for n64.
Also, the generic unix mips64 sysdep is essentially the same,
only the load instruction need to be adjusted depending of the
ABI.
Checked on mips64-linux-gnu and mips64n32-linux-gnu.
It changes the ia64 INTERNAL_SYSCALL_NCS macro to return a negative
value instead of the 'r10' register value on the 'err' macro argument.
The macro INTERNAL_SYSCALL_DECL is no longer required, and the
INTERNAL_SYSCALL_ERROR_P macro follows the other Linux kABIs.
Checked on ia64-linux-gnu.
It highly unlikely that alpha will be ported to anything else than
Linux, so this patch moves the generic unix syscall definition to
Linux and adapt it to Linux kernel ABI.
It changes the internal_syscall* macros to return a negative value
instead of the '$19' register value on the 'err' macro argument.
The macro INTERNAL_SYSCALL_DECL is no longer required, and the
INTERNAL_SYSCALL_ERROR_P macro follows the other Linux kABIs.
Checked on alpha-linux-gnu.
The sparc INTERNAL_SYSCALL macro might clobber the register
parameter if the argument itself might clobber any register (a function
call for instance).
This patch fixes it by using temporary variables for the expressions
between the register assignments (as indicated by GCC documentation,
6.47.5.2 Specifying Registers for Local Variables).
It is similar to the fix done for MIPS (bug 25523).
Checked on sparc64-linux-gnu and sparcv9-linux-gnu.
It changes the sparc internal_syscall* macros to return a negative
value instead of the 'g1' register value in the 'err' macro argument.
The __SYSCALL_STRING macro is also changed to no set the 'g1'
value, since 'o1' already holds all the required information
to check if syscall has failed.
The macro INTERNAL_SYSCALL_DECL is no longer required, and the
INTERNAL_SYSCALL_ERROR_P macro follows the other Linux kABIs.
The redefinition of INTERNAL_VSYSCALL_CALL is also no longer
required.
Checked on sparc64-linux-gnu and sparcv9-linux-gnu. It fixes
the sporadic issues on sparc32 where clock_nanosleep does not
act as cancellation entrypoint.
It changes the powerpc INTERNAL_VSYSCALL_CALL and INTERNAL_SYSCALL_NCS
to return a negative value instead of the returning the CR value in
the 'err' macro argument.
The macro INTERNAL_SYSCALL_DECL is no longer required, and the
INTERNAL_SYSCALL_ERROR_P macro follows the other Linux kABIs.
Checked on powerpc64-linux-gnu, powerpc64le-linux-gnu, and
powerpc-linux-gnu-power4.
The diferences between powerpc64{le} and powerpc32 Linux sysdep.h
are:
1. On both vDSO and syscall macros the volatile registers r9, r10,
r11, and r12 are used as input operands on powerpc32 and as
clobber registers on powerpc64. However the outcome is essentially
the same, it advertise the register might be clobbered by the
kernel (although Linux won't leak register information to userland
in such case).
2. The LOADARGS* macros uses a different size to check for invalid
types.
3. The pointer mangling support guard pointer loading uses ABI
specific instruction and register.
This patch consolidates on only one sysdep by using the the powerpc64
version as default and add the adjustments required for powerpc32.
Checked on powerpc64-linux-gnu, powerpc64le-linux-gnu, and
powerpc-linux-gnu-power4.
1. getcontext and swapcontext are updated to save the caller's shadow
stack pointer and return address.
2. setcontext and swapcontext are updated to restore shadow stack and
jump to new context directly.
3. makecontext is updated to allocate a new shadow stack and set the
caller's return address to the helper code, L(exitcode).
4. Since we no longer save and restore EAX, ECX and EDX in getcontext,
setcontext and swapcontext, we can use them as scratch register slots
to enable CET in ucontext functions.
Since makecontext allocates a new shadow stack when making a new
context and kernel allocates a new shadow stack for clone/fork/vfork
syscalls, we track the current shadow stack base. In setcontext and
swapcontext, if the target shadow stack base is the same as the current
shadow stack base, we unwind the shadow stack. Otherwise it is a stack
switch and we look for a restore token.
We enable shadow stack at run-time only if program and all used shared
objects, including dlopened ones, are shadow stack enabled, which means
that they must be compiled with GCC 8 or above and glibc 2.28 or above.
We need to save and restore shadow stack only if shadow stack is enabled.
When caller of getcontext, setcontext, swapcontext and makecontext is
compiled with smaller ucontext_t, shadow stack won't be enabled at
run-time. We check if shadow stack is enabled before accessing the
extended field in ucontext_t.
Tested on i386 CET/non-CET machines.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
We can't include sysdep.h in the test case (it introduces lots of
strange failures) so __NR_futex isn't redifined to __NR_futex_time64 by
64-bit time_t 32-bit archs (y2038 safe).
To allow the test to pass let's just do the __NR_futex_time64 syscall if
we don't have __NR_futex defined.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The 32-bit protection key behavior is somewhat unclear on 32-bit powerpc,
so this change is restricted to the 64-bit variants.
Flag translation is needed because of hardware differences between the
POWER implementation (read and write flags) and the Intel implementation
(write and read+write flags).
Reuse the template in order to provide the redirect for
scalbl to __scalbieee128, but avoid any extra aliasing
as this is intended to support long double redirects only.
This is a preparatory patch to enable building a _Float128
variant to ease reuse when building a _Float128 variant to
alias this long double only symbol.
Notably, stubs are added where missing to the native _Float128
sysdep dir to prevent building these newly templated variants
created inside the build directories.
Also noteworthy are the changes around LIBM_SVID_COMPAT. These
changes are not intuitive. The templated version is only
enabled when !LIBM_SVID_COMPAT, and the compat version is
predicated entirely on LIBM_SVID_COMPAT. Thus, exactly one is
stubbed out entirely when building. The nldbl scalb compat
files are updated to account for this.
Likewise, fixup the reuse of m68k's e_scalb{f,l}.c to include
it's override of e_scalb.c. Otherwise, the search path finds
the templated copy in the build directory. This could be
futher simplified by providing an overridden template, but I
lack the hardware to verify.
A recent discussion in bug 14469 notes that a threshold in float
Bessel function implementations, used to determine when to use a
simpler implementation approach, results in substantially inaccurate
results.
As I discussed in
<https://sourceware.org/ml/libc-alpha/2013-03/msg00345.html>, a
heuristic argument suggests 2^(S+P) as the right order of magnitude
for a suitable threshold, where S is the number of significand bits in
the floating-point type and P is the number of significant bits in the
representation of the floating-point type, and the float and ldbl-96
implementations use thresholds that are too small. Some threshold
does need using, there or elsewhere in the implementation, to avoid
spurious underflow and overflow for large arguments.
This patch sets the thresholds in the affected implementations to more
heuristically justifiable values. Results will still be inaccurate
close to zeroes of the functions (thus this patch does *not* fix any
of the bugs for Bessel function inaccuracy); fixing that would require
a different implementation approach, likely along the lines described
in <http://www.cl.cam.ac.uk/~jrh13/papers/bessel.ps.gz>.
So the justification for a change such as this would be statistical
rather than based on particular tests that had excessive errors and no
longer do so (no doubt such tests could be found, but would probably
be too fragile to add to the testsuite, as liable to give large errors
again from very small implementation changes or even from compiler
changes). See
<https://sourceware.org/ml/libc-alpha/2020-02/msg00638.html> for such
statistics of the resulting improvements for float functions.
Tested (glibc testsuite) for x86_64.
__resolv_conf_get_current should only record the initial file
change data if after verifying that file just read matches the
original measurement. Fixes commit aef16cc8a4
("resolv: Automatically reload a changed /etc/resolv.conf file
[BZ #984]").
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The data is captured after reading the file. This allows callers
to check the change data against an earlier measurement.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
res_vinit_1 did not close the stream on errors, only on success.
This change moves closing the stream to __resolv_conf_load, for both
the success and error cases.
Fixes commit 89f187a40f ("resolv: Use
getline for configuration file reading in res_vinit_1") and commit
3f853f22c8 ("resolv: Lift domain search
list limits [BZ #19569] [BZ #21475]"), where memory allocation was
introduced into res_vinit_1.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Only minor functional changes (i.e., regarding the handling of
directories, which are now treated as empty files).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This patch adds the new STATX_ATTR_VERITY macro from Linux 5.5 to
glibc's bits/statx-generic.h. (This only does anything if glibc is
being used with old kernel headers.)
Tested for x86_64.
A non-ascii character in the installed headers leads now to:
error: failure to convert ascii to UTF-8
Such a finding in s390 specific fenv.h leads to fails in GCC testsuite.
See glibc commit 08aea89ef6.
Adding this gcc option also to our tests was proposed by Florian Weimer.
This change also found a hit in resource.h where now "microseconds" is used.
I've adjusted all the resource.h files.
I've used the following command to check for further hits in headers.
LC_ALL=C find -name "*.h" -exec grep -PHn "[\x80-\xFF]" {} \;
Tested on s390x and x86_64.
Reviewed-by: Zack Weinberg <zackw@panix.com>
By undef strong_alias on alpha implementation, the
default_symbol_version macro becomes an empty macro on static build.
It fixes the issue introduced at c953219420.
Checked on alpha-linux-gnu with a 'make check run-built-tests=no'.
Bug 25487 reports stack corruption in ldbl-96 sinl on a pseudo-zero
argument (an representation where all the significand bits, including
the explicit high bit, are zero, but the exponent is not zero, which
is not a valid representation for the long double type).
Although this is not a valid long double representation, existing
practice in this area (see bug 4586, originally marked invalid but
subsequently fixed) is that we still seek to avoid invalid memory
accesses as a result, in case of programs that treat arbitrary binary
data as long double representations, although the invalid
representations of the ldbl-96 format do not need to be consistently
handled the same as any particular valid representation.
This patch makes the range reduction detect pseudo-zero and unnormal
representations that would otherwise go to __kernel_rem_pio2, and
returns a NaN for them instead of continuing with the range reduction
process. (Pseudo-zero and unnormal representations whose unbiased
exponent is less than -1 have already been safely returned from the
function before this point without going through the rest of range
reduction.) Pseudo-zero representations would previously result in
the value passed to __kernel_rem_pio2 being all-zero, which is
definitely unsafe; unnormal representations would previously result in
a value passed whose high bit is zero, which might well be unsafe
since that is not a form of input expected by __kernel_rem_pio2.
Tested for x86_64.
According to [gcc documentation][1], temporary variables must be used for
the desired content to not be call-clobbered.
Fix the Linux inline syscall templates by adding temporary variables,
much like what x86 did before
(commit 381a0c26d7).
Tested with gcc 9.2.0, both cross-compiled and natively on Loongson
3A4000.
[1]: https://gcc.gnu.org/onlinedocs/gcc/Local-Register-Variables.html
