the kernel uses long longs in the struct, but the documentation
says they're long. so we need to fixup the mismatch between the
userspace and kernelspace structs.
since the struct offers a mem_unit member, we can avoid truncation
by adjusting that value.
The architecture-specific assembly versions of clone did not set errno on
failure, which is inconsistent with glibc. __clone still returns the error
via its return value, and clone is now a wrapper that sets errno as needed.
The public clone has also been moved to src/linux, as it's not directly
related to the pthreads API.
__clone is called by pthread_create, which does not report errors via
errno. Though not strictly necessary, it's nice to avoid clobbering errno
here.
it's unclear what the historical signature for this function was, but
semantically, the argument should be a pointer to const, and this is
what glibc uses. correct programs should not be using this function
anyway, so it's unlikely to matter.
this was wrong since the original commit adding inotify, and I don't
see any explanation for it. not even the man pages have it wrong. it
was most likely a copy-and-paste error.
the header is included only as a guard to check that the declaration
and definition match, so the typo didn't cause any breakage aside
from omitting this check.
the reasons are the same as for sbrk. unlike sbrk, there is no safe
usage because brk does not return any useful information, so it should
just fail unconditionally.
use of sbrk is never safe; it conflicts with malloc, and malloc may be
used internally by the implementation basically anywhere. prior to
this change, applications attempting to use sbrk to do their own heap
management simply caused untrackable memory corruption; now, they will
fail with ENOMEM allowing the errors to be fixed.
sbrk(0) is still permitted as a way to get the current brk; some
misguided applications use this as a measurement of their memory
usage or for other related purposes, and such usage is harmless.
eventually sbrk may be re-added if/when malloc is changed to avoid
using the brk by using mmap for all allocations.
also include fallback code for broken kernels that don't support the
flags. as usual, the fallback has a race condition that can leak file
descriptors.
the issue at hand is that many syscalls require as an argument the
kernel-ABI size of sigset_t, intended to allow the kernel to switch to
a larger sigset_t in the future. previously, each arch was defining
this size in syscall_arch.h, which was redundant with the definition
of _NSIG in bits/signal.h. as it's used in some not-quite-portable
application code as well, _NSIG is much more likely to be recognized
and understood immediately by someone reading the code, and it's also
shorter and less cluttered.
note that _NSIG is actually 65/129, not 64/128, but the division takes
care of throwing away the off-by-one part.
if there's evidence of any use for it, we can add it back later. as
far as I can tell, glibc has it only for internal use (and musl uses a
direct syscall in that case rather than a function call), not for
exposing it to applications.
based on proposal by Isaac Dunham. nonexistance of bits/io.h will
cause inclusion of sys/io.h to produce an error on archs that are not
supposed to have it. this is probably the desired behavior, but the
error message may be a bit unusual.
something is wrong with the logic for the argument layout, resulting
in compile errors on mips due to too many args to syscall... further
information on how it's supposed to work will be needed before it can
be reactivated.
previously, it was pretty much random which one of these trees a given
function appeared in. they have now been organized into:
src/linux: non-POSIX linux syscalls (possibly shard with other nixen)
src/legacy: various obsolete/legacy functions, mostly wrappers
src/misc: still mostly uncategorized; some misc POSIX, some nonstd
src/crypt: crypt hash functions
further cleanup will be done later.
note that POSIX does not specify these functions as _Noreturn, because
POSIX is aligned with C99, not the new C11 standard. when POSIX is
eventually updated to C11, it will almost surely give these functions
the _Noreturn attribute. for now, the actual _Noreturn keyword is not
used anyway when compiling with a c99 compiler, which is what POSIX
requires; the GCC __attribute__ is used instead if it's available,
however.
in a few places, I've added infinite for loops at the end of _Noreturn
functions to silence compiler warnings. presumably
__buildin_unreachable could achieve the same thing, but it would only
work on newer GCCs and would not be portable. the loops should have
near-zero code size cost anyway.
like the previous _Noreturn commit, this one is based on patches
contributed by philomath.
some minor changes to how hard-coded sets for thread-related purposes
are handled were also needed, since the old object sizes were not
necessarily sufficient. things have gotten a bit ugly in this area,
and i think a cleanup is in order at some point, but for now the goal
is just to get the code working on all supported archs including mips,
which was badly broken by linux rejecting syscalls with the wrong
sigset_t size.
based on patches by orc and Isaac Dunham, with some fixes. sys/io.h
exists and contains prototypes for these functions regardless of
whether the target arch has them; this is a bit unorthodox but I don't
think it will break anything. the function definitions do not exist
unless the appropriate SYS_* syscall number macro is defined, which
should make sure configure scripts looking for these functions don't
find them on other systems.
presently, sys/io.h does not have the inb/outb/etc. port io
macros/functions. I'd be surprised if ioperm/iopl are useful without
them, so they probably need to be added at some point in appropriate
bits/io.h files...
these are not exposed publicly in any header, but the few programs
that use them (modutils/kmod, etc.) are declaring the functions
themselves rather than making the syscalls directly, and it doesn't
really hurt to have them (same as the capset junk).
these were left in glibc for binary compatibility after the public
part of the interface was removed, and libcap kept using them (with
its own copy of the header files) rather than just making the syscalls
directly. might as well add them since they're so small...
- add the rest of the junk traditionally in sys/param.h
- add prototypes for some nonstandard functions
- add _GNU_SOURCE to their source files so the compiler can check proto
