commit 895736d49b made these changes
along with fixing a real bug in LOG_MAKEPRI. based on further
information, they do not seem to be well-motivated or in line with
policy.
the result of LOG_FAC is not a meaningful facility value if we shift
it down like before, but apparently the way it is used by applications
is as an index into an array of facility names. moreover, all
historical systems which define it do so with the shift. as it is a
nonstandard interface, there is no justification for providing a macro
by the same name that is incompatible with historical practice.
the value of LOG_FACMASK likewise is 0x3f8 on all historical systems
checked. while only 5 bits are used for existing facility codes, the
convention seems to be that all 7 bits belong to the facility field
and theoretically could be used to expand to having more facilities.
that seems unlikely to happen, but there is no reason to make a
gratuitously incompatible change here.
Per RFC 5952, ties for longest sequence of zero fields must be broken
by choosing the earliest, but the implementation put the leading
sequence of zeros at a disadvantage. That's because for example when
compressing "0:0:0:10:0:0:0:10" the strspn(buf+i, ":0") call returns 6
for the first sequence and 7 for the second one – the second sequence
has the benefit of a leading colon.
Changing the condition to require beating the leading sequence by not
one but two characters resolves the issue.
while commit 53ac44ff4c fixed the temp
buffer being undersized, the use of a temp buffer to begin with was a
mistake. instead, compare the requested symbol name in-place and use
the already-null-terminated copy of the name without "64" present in
lfs64_list[] to look up the real symbol.
add two ioctls to get and set struct epoll_params to allow users to
control epoll based busy polling of network sockets.
added to uapi in commit 18e2bf0edf4dd88d9656ec92395aa47392e85b61 (Linux
kernel 6.9 and newer).
this interface does not have a lot of historical consensus on how it
handles the contents of the /etc/shells file in regard to whitespace
and comments, but the commonality between all checked is that they
ignore lines that are blank or that begin with '#', so that is the
behavior we adopt.
these are nonstandard and unnecessary for using the associated
functionality, but resulted in applications that used them
malfunctioning.
patch based on proposed fix by erny hombre.
This syscall is available since Linux 3.15 and also implemented in
glibc from version 2.28. It is commonly used in filesystem or security
contexts.
Constants RENAME_NOREPLACE, RENAME_EXCHANGE, RENAME_WHITEOUT are
guarded by _GNU_SOURCE as with glibc.
commit 1b0d48517f wrongly copied the
getdents return type of int rather than matching the ssize_t used by
posix_getdents. this was overlooked in testing on 32-bit archs but
obviously broke 64-bit archs.
without explicit alignment directives, whether they end up at the
necessary alignment depends on linker/linking conditions. initially
reported as mold issue 1255.
this interface was added as the outcome of Austin Group tracker issue
697. no error is specified for unsupported flags, which is probably an
oversight. for now, EOPNOTSUPP is used so as not to overload EINVAL.
the bits file is retained, but as a single generic version, to allow
for the unlikely future possibility of letting a new arch define
something differently.
previously, only a few archs defined it here. this change makes the
presence consistent across all archs, and reduces the amount of header
duplication (and potential for future inconsistency) between archs.
this change is purely to document that they are the same in
preparation to remove the arch-specific headers for these archs and
replace them with a generic version that matches riscv32 and can be
shared by these and all future archs.
commit f47a8cdd25 introduced an
alternate mechanism for access to runtime page size for compatibility
with early stages of dynamic linking, but because pthread_impl.h
indirectly includes libc.h, the condition #ifndef PAGE_SIZE was never
satisfied.
rather than depend on order of inclusion, use the (baseline POSIX)
macro PAGESIZE, not the (XSI) macro PAGE_SIZE, to determine whether
page size is dynamic. our internal libc.h only provides a dynamic
definition for PAGE_SIZE, not for PAGESIZE.
the %s conversion is added as the outcome of Austin Group tracker
issue 169 and its unspecified behavior is clarified as the outcome of
issue 1727.
the %F, %g, %G, %u, %V, %z, and %Z conversions are added as the
outcome of Austin Group tracker issue 879 for alignment with strftime
and the behaviors of %u, %z, and %Z are defined as the outcome of
issue 1727.
at this time, the conversions with unspecified effects on struct tm
are all left as parse-only no-ops. this may be changed at a later
time, particularly for %s, if there is reasonable cross-implementation
consensus outside the standards process on what the behavior should
be.
once the remaining value is less than 10, the modulo operation to
produce the final digit and division to prepare for next loop
iteration can be dropped. this may be a meaningful performance
distinction when formatting low-magnitude numbers in bulk, and should
never hurt.
based on patch by Viktor Reznov.
historically linux limited the number of supplementary groups a
process could be in to 32, but this limit was raised to 65536 in linux
2.6.4. proposals to support the new limit, change NGROUPS_MAX, or make
it dynamic have been stalled due to the impact it would have on
initgroups where the groups array exists in automatic storage.
the changes here decouple initgroups from the value of NGROUPS_MAX and
allow it to fall back to allocating a buffer in the case where
getgrouplist indicates the user has more supplementary groups than
could be reported in the buffer. getgrouplist already involves
allocation, so this does not pull in any new link dependency.
likewise, getgrouplist is already using the public malloc (vs internal
libc one), so initgroups does the same. if this turns out not to be
the best choice, both can be changed together later.
the initial buffer size is left at 32, but now as the literal value,
so that any potential future change to NGROUPS_MAX will not affect
initgroups.
commit cfa0a54c08 attempted to fix
rounding on archs where long double is not 80-bit (where LDBL_MANT_DIG
is not zero mod four), but failed to address the edge case where
rounding was skipped because LDBL_MANT_DIG/4 rounded down in the
comparison against the requested precision.
the rounding logic based on hex digit count is difficult to understand
and not well-motivated, so rather than try to fix it, replace it with
an explicit calculation in terms of number of bits to be kept, without
any truncating division operations. based on patch by Peter Ammon, but
with scalbn to apply the rounding exponent since the value will not
generally fit in any integer type. scalbn is used instead of scalbnl
to avoid pulling in the latter unnecessarily, since the value is an
exact power of two whose exponent range is bounded by LDBL_MANT_DIG, a
small integer.
The principal expressions defining acosh and acos are such that
acosh(z) = ±i acos(z)
where the + is only true on the Im(z)>0 half of the complex plane
(and partly on Im(z)==0 depending on number representation).
fix the comment without expanding on the details.
POSIX requires pwrite to honor the explicit file offset where the
write should take place even if the file was opened as O_APPEND.
however, linux historically defined the pwrite syscall family as
honoring O_APPEND. this cannot be changed on the kernel side due to
stability policy, but the addition of the pwritev2 syscall with a
flags argument opened the door to fixing it, and linux commit
73fa7547c70b32cc69685f79be31135797734eb6 adds the RWF_NOAPPEND flag
that lets us request a write honoring the file offset argument.
this patch changes the pwrite function to first attempt using the
pwritev2 syscall with RWF_NOAPPEND, falling back to using the old
pwrite syscall only after checking that O_APPEND is not set for the
open file. if O_APPEND is set, the operation fails with EOPNOTSUPP,
reflecting that the kernel does not support the correct behavior. this
is an extended error case needed to avoid the wrong behavior that
happened before (writing the data at the wrong location), and is
aligned with the spirit of the POSIX requirement that "An attempt to
perform a pwrite() on a file that is incapable of seeking shall result
in an error."
since the pwritev2 syscall interprets the offset of -1 as a request to
write at the current file offset, it is mapped to a different negative
value that will produce the expected error.
pwritev, though not governed by POSIX at this time, is adjusted to
match pwrite in honoring the offset.
added in linux kernel commit 73fa7547c70b32cc69685f79be31135797734eb6.
this is added now as a prerequisite for fixing pwrite/pwritev behavior
for O_APPEND files.
the jis0208 table we use is only 84x94 in size, but the shift_jis
encoding supports a 94x94 grid. attempts to convert sequences outside
of the supported zone resulted in out-of-bounds table reads,
misinterpreting adjacent rodata as part of the character table and
thereby converting these sequences to unexpected characters.
this is not needed, but may act as a hint to the compiler, and also
serves to suppress unused function warnings if enabled (on by default
since commit 86ac0f7947).
this is how it's defined in the cp936 document referenced by the IANA
charset registry as defining GBK, and of the mappings defined there,
was the only one missing.
it is not accepted for GB18030, as GB18030 is a UTF and has its own
unique mapping for the euro symbol.
- add mount_setattr from linux v5.12
- add epoll_pwait2 from linux v5.11
- add process_madvise from linux v5.10
- add __NR_faccessat2 from linux v5.8
- add pidfd_getfd and openat2 syscall numbers from linux v5.6
- add clone3 syscall number from linux v5.3
- add process_mrelease from linux v5.15
- add futex_waitv from linux v5.16
- add set_mempolicy_home_node from linux v5.17
- add cachestat from linux v6.4
- add __NR_fchmodat2 from linux v6.6
despite riscv32 being natively time64, the IPC_TIME64 bit (0x100) is
set in IPC_STAT and derived command macros, differentiating their
values from the raw command values used to interface with the kernel.
this reflects that the kernel ipc structure types are not natively
time64, but have broken-down hi/lo fields that cannot be used in-place
and require translation, and that the userspace struct types differ
from the kernel types (relevant to things like strace).
These are mostly copied from riscv64. _Addr and _Reg had to become int
to match compiler-controlled parts of the ABI (result type of sizeof,
etc.). There is no kernel stat struct; the userspace stat matches
glibc in the sizes and offsets of all fields (including glibc's
__dev_t __pad1). The jump buffer is 12 words larger to account for 12
saved double-precision floats; additionally it should be 64-bit
aligned to save doubles.
The syscall list was significantly revised by deleting all time32 and
pre-statx syscalls, and renaming several syscalls that have different
names depending on __BITS_PER_LONG, notably mmap2 and _llseek.
futex was added as an alias to futex_time64 since it is widely used by
software which does not pass time arguments.
Rich Felker
Jakub Stasiak
Joe Damato
Florian Ziesche
Tony Ambardar
mojyack
Gonzalo Alvarez
Michael Forney
Szabolcs Nagy
wanghongliang
Stefan O'Rear
Khem Raj