| Commit message (Expand) | Author | Files | Lines |
|---|
| 2015-06-23 | reimplement strverscmp to fix corner cases•••this interface is non-standardized and is a GNU invention, and as
such, our implementation should match the behavior of the GNU
function. one peculiarity the old implementation got wrong was the
handling of all-zero digit sequences: they are supposed to compare
greater than digit sequences of which they are a proper prefix, as in
009 < 00.
in addition, high bytes were treated with char signedness rather than
as unsigned. this was wrong regardless of what the GNU function does
since the resulting order relation varied by arch.
the new strverscmp implementation makes explicit the cases where the
order differs from what strcmp would produce, of which there are only
two.
| Rich Felker | 1 | -32/+25 |
| 2015-06-22 | fix regression/typo that disabled __simple_malloc when calloc is used•••commit ba819787ee93ceae94efd274f7849e317c1bff58 introduced this
regression. since the __malloc0 weak alias was not properly provided
by __simple_malloc, use of calloc forced the full malloc to be linked.
| Rich Felker | 1 | -1/+1 |
| 2015-06-22 | fix calloc when __simple_malloc implementation is used•••previously, calloc's implementation encoded assumptions about the
implementation of malloc, accessing a size_t word just prior to the
allocated memory to determine if it was obtained by mmap to optimize
out the zero-filling. when __simple_malloc is used (static linking a
program with no realloc/free), it doesn't matter if the result of this
check is wrong, since all allocations are zero-initialized anyway. but
the access could be invalid if it crosses a page boundary or if the
pointer is not sufficiently aligned, which can happen for very small
allocations.
this patch fixes the issue by moving the zero-fill logic into malloc.c
with the full malloc, as a new function named __malloc0, which is
provided by a weak alias to __simple_malloc (which always gives
zero-filled memory) when the full malloc is not in use.
| Rich Felker | 3 | -12/+15 |
| 2015-06-20 | provide __stack_chk_fail_local in libc.a•••this symbol is needed only on archs where the PLT call ABI is klunky,
and only for position-independent code compiled with stack protector.
thus references usually only appear in shared libraries or PIE
executables, but they can also appear when linking statically if some
of the object files being linked were built as PIC/PIE.
normally libssp_nonshared.a from the compiler toolchain should provide
__stack_chk_fail_local, but reportedly it appears prior to -lc in the
link order, thus failing to satisfy references from libc itself (which
arise only if libc.a was built as PIC/PIE with stack protector
enabled).
| Rich Felker | 1 | -0/+4 |
| 2015-06-20 | work around mips detached thread exit breakage due to kernel regression•••linux kernel commit 46e12c07b3b9603c60fc1d421ff18618241cb081 caused
the mips syscall mechanism to fail with EFAULT when the userspace
stack pointer is invalid, breaking __unmapself used for detached
thread exit. the workaround is to set $sp to a known-valid, readable
address, and the simplest one to obtain is the address of the current
function, which is available (per o32 calling convention) in $25.
| Rich Felker | 1 | -0/+1 |
| 2015-06-17 | ignore ENOSYS error from mprotect in pthread_create and dynamic linker•••this error simply indicated a system without memory protection (NOMMU)
and should not cause failure in the caller.
| Rich Felker | 2 | -3/+6 |
| 2015-06-16 | switch to using trap number 31 for syscalls on sh•••nominally the low bits of the trap number on sh are the number of
syscall arguments, but they have never been used by the kernel, and
some code making syscalls does not even know the number of arguments
and needs to pass an arbitrary high number anyway.
sh3/sh4 traditionally used the trap range 16-31 for syscalls, but part
of this range overlapped with hardware exceptions/interrupts on sh2
hardware, so an incompatible range 32-47 was chosen for sh2.
using trap number 31 everywhere, since it's in the existing sh3/sh4
range and does not conflict with sh2 hardware, is a proposed
unification of the kernel syscall convention that will allow binaries
to be shared between sh2 and sh3/sh4. if this is not accepted into the
kernel, we can refit the sh2 target with runtime selection mechanisms
for the trap number, but doing so would be invasive and would entail
non-trivial overhead.
| Rich Felker | 8 | -11/+11 |
| 2015-06-16 | switch sh port's __unmapself to generic version when running on sh2/nommu•••due to the way the interrupt and syscall trap mechanism works,
userspace on sh2 must never set the stack pointer to an invalid value.
thus, the approach used on most archs, where __unmapself executes with
no stack for the interval between SYS_munmap and SYS_exit, is not
viable on sh2.
in order not to pessimize sh3/sh4, the sh asm version of __unmapself
is not removed. instead it's renamed and redirected through code that
calls either the generic (safe) __unmapself or the sh3/sh4 asm,
depending on compile-time and run-time conditions.
| Rich Felker | 2 | -3/+22 |
| 2015-06-16 | add support for sh2 interrupt-masking-based atomics to sh port•••the sh2 target is being considered an ISA subset of sh3/sh4, in the
sense that binaries built for sh2 are intended to be usable on later
cpu models/kernels with mmu support. so rather than hard-coding
sh2-specific atomics, the runtime atomic selection mechanisms that was
already in place has been extended to add sh2 atomics.
at this time, the sh2 atomics are not SMP-compatible; since the ISA
lacks actual atomic operations, the new code instead masks interrupts
for the duration of the atomic operation, producing an atomic result
on single-core. this is only possible because the kernel/hardware does
not impose protections against userspace doing so. additional changes
will be needed to support future SMP systems.
care has been taken to avoid producing significant additional code
size in the case where it's known at compile-time that the target is
not sh2 and does not need sh2-specific code.
| Rich Felker | 4 | -14/+113 |
| 2015-06-16 | refactor stdio open file list handling, move it out of global libc struct•••functions which open in-memory FILE stream variants all shared a tail
with __fdopen, adding the FILE structure to stdio's open file list.
replacing this common tail with a function call reduces code size and
duplication of logic. the list is also partially encapsulated now.
function signatures were chosen to facilitate tail call optimization
and reduce the need for additional accessor functions.
with these changes, static linked programs that do not use stdio no
longer have an open file list at all.
| Rich Felker | 12 | -41/+42 |
| 2015-06-16 | byte-based C locale, phase 3: make MB_CUR_MAX variable to activate code•••this patch activates the new byte-based C locale (high bytes treated
as abstract code unit "characters" rather than decoded as multibyte
characters) by making the value of MB_CUR_MAX depend on the active
locale. for the C locale, the LC_CTYPE category pointer is null,
yielding a value of 1. all other locales yield a value of 4.
| Rich Felker | 2 | -1/+5 |
| 2015-06-16 | byte-based C locale, phase 2: stdio and iconv (multibyte callers)•••this patch adjusts libc components which use the multibyte functions
internally, and which depend on them operating in a particular
encoding, to make the appropriate locale changes before calling them
and restore the calling thread's locale afterwards. activating the
byte-based C locale without these changes would cause regressions in
stdio and iconv.
in the case of iconv, the current implementation was simply using the
multibyte functions as UTF-8 conversions. setting a multibyte UTF-8
locale for the duration of the iconv operation allows the code to
continue working.
in the case of stdio, POSIX requires that FILE streams have an
encoding rule bound at the time of setting wide orientation. as long
as all locales, including the C locale, used the same encoding,
treating high bytes as UTF-8, there was no need to store an encoding
rule as part of the stream's state.
a new locale field in the FILE structure points to the locale that
should be made active during fgetwc/fputwc/ungetwc on the stream. it
cannot point to the locale active at the time the stream becomes
oriented, because this locale could be mutable (the global locale) or
could be destroyed (locale_t objects produced by newlocale) before the
stream is closed. instead, a pointer to the static C or C.UTF-8 locale
object added in commit commit aeeac9ca5490d7d90fe061ab72da446c01ddf746
is used. this is valid since categories other than LC_CTYPE will not
affect these functions.
| Rich Felker | 7 | -8/+40 |
| 2015-06-16 | byte-based C locale, phase 1: multibyte character handling functions•••this patch makes the functions which work directly on multibyte
characters treat the high bytes as individual abstract code units
rather than as multibyte sequences when MB_CUR_MAX is 1. since
MB_CUR_MAX is presently defined as a constant 4, all of the new code
added is dead code, and optimizing compilers' code generation should
not be affected at all. a future commit will activate the new code.
as abstract code units, bytes 0x80 to 0xff are represented by wchar_t
values 0xdf80 to 0xdfff, at the end of the surrogates range. this
ensures that they will never be misinterpreted as Unicode characters,
and that all wctype functions return false for these "characters"
without needing locale-specific logic. a high range outside of Unicode
such as 0x7fffff80 to 0x7fffffff was also considered, but since C11's
char16_t also needs to be able to represent conversions of these
bytes, the surrogate range was the natural choice.
| Rich Felker | 10 | -7/+53 |
| 2015-06-16 | fix btowc corner case•••btowc is required to interpret its argument by conversion to unsigned
char, unless the argument is equal to EOF. since the conversion to
produces a non-character value anyway, we can just unconditionally
convert, for now.
| Rich Felker | 1 | -0/+1 |
| 2015-06-14 | arm: add vdso support•••vdso will be available on arm in linux v4.2, the user-space code
for it is in kernel commit 8512287a8165592466cb9cb347ba94892e9c56a5
| Szabolcs Nagy | 1 | -0/+4 |
| 2015-06-14 | refactor malloc's expand_heap to share with __simple_malloc•••this extends the brk/stack collision protection added to full malloc
in commit 276904c2f6bde3a31a24ebfa201482601d18b4f9 to also protect the
__simple_malloc function used in static-linked programs that don't
reference the free function.
it also extends support for using mmap when brk fails, which full
malloc got in commit 5446303328adf4b4e36d9fba21848e6feb55fab4, to
__simple_malloc.
since __simple_malloc may expand the heap by arbitrarily large
increments, the stack collision detection is enhanced to detect
interval overlap rather than just proximity of a single address to the
stack. code size is increased a bit, but this is partly offset by the
sharing of code between the two malloc implementations, which due to
linking semantics, both get linked in a program that needs the full
malloc with realloc/free support.
| Rich Felker | 3 | -81/+126 |
| 2015-06-13 | remove cancellation points in stdio•••commit 58165923890865a6ac042fafce13f440ee986fd9 added these optional
cancellation points on the basis that cancellable stdio could be
useful, to unblock threads stuck on stdio operations that will never
complete. however, the only way to ensure that cancellation can
achieve this is to violate the rules for side effects when
cancellation is acted upon, discarding knowledge of any partial data
transfer already completed. our implementation exhibited this behavior
and was thus non-conforming.
in addition to improving correctness, removing these cancellation
points moderately reduces code size, and should significantly improve
performance on i386, where sysenter/syscall instructions can be used
instead of "int $128" for non-cancellable syscalls.
| Rich Felker | 3 | -24/+3 |
| 2015-06-13 | fix idiom for setting stdio stream orientation to wide•••the old idiom, f->mode |= f->mode+1, was adapted from the idiom for
setting byte orientation, f->mode |= f->mode-1, but the adaptation was
incorrect. unless the stream was alreasdy set byte-oriented, this code
incremented f->mode each time it was executed, which would eventually
lead to overflow. it could be fixed by changing it to f->mode |= 1,
but upcoming changes will require slightly more work at the time of
wide orientation, so it makes sense to just call fwide. as an
optimization in the single-character functions, fwide is only called
if the stream is not already wide-oriented.
| Rich Felker | 6 | -6/+6 |
| 2015-06-13 | add printing of null %s arguments as "(null)" in wide printf•••this is undefined, but supported in our implementation of the normal
printf, so for consistency the wide variant should support it too.
| Rich Felker | 1 | -0/+1 |
| 2015-06-13 | add %m support to wide printf | Rich Felker | 1 | -0/+2 |
