It's established enough in non-legacy code that this is a terrible idea.
Even if we add getentropy it's not a comparable API (not a userspace RNG
capable of streaming large numbers of bytes, doesn't have _uniform, etc).
"Feel free to remove that line!" - riastradh
it aliased with. Assert that the alignment actually used reflects the
alignment required by existing implementation and for newly build
modules assert that it is at most the guaranteed alignment.
This is intended for 68060:
- GCC does not emit __muldi3() for 68020-40, that have 32 * 32 --> 64 mulul
- mulsl (and moveml), used in this code, are not implemented for 68010
In comparison with that from compiler_rt, this version saves:
- 12% of processing time
- 12 bytes of stack
- 50 bytes of code size
Also, slightly faster, memory saving, and smaller than libgcc version.
By examining with evcnt(9), __muldi3() is invoked more than 1000 times per
sec by kernel, which should justify to introduce assembler version of this
function.
This ldexp stub will shadow the ldexp weak alias for scalbn in libm,
which is unfortunate but hard to fix properly without chasing the
mythical libc bump beast. With the change here, we should raise all
the same exceptions that libm's scalbn does -- overflow, underflow,
inexact-result, and (for signalling NaN only) invalid-operation.
This in turn should correct the missing overflow/underflow exceptions
of our portable C fma, and perhaps other routines.
XXX pullup
- lock all relevant mutexes just before fork
- unlock all mutexes just after fork in the parent
- full reinit non-spinlocks in the child
This is not using the normal pthread_atfork interface to ensure order of
operation, malloc is used as implementation detail too often.
They deliver the logic of bypassing selected signals directly to the
debuggee, without informing the debugger.
This can be used to implement the QPassSignals GDB/LLDB protocol.
This call can be useful to avoid signal races in ATF ptrace tests.
CLONE_PID was removed in Linux 2.5.15 and recycled for
CLONE_PIDFD since Linux 5.2.
CLONE_STOPPED was removed in Linux 2.6.38 and recycled
for CLONE_NEWCGROUP since Linux 4.6.
the environment rather than simply turning into posix_spawn() in that case.
Also, we cannot use strtok() to parse PATH, the semantics don't fit the API.
Borrow the guts of execvp for the PATH search.
We still simply check for a file with 'x' permission, and assume that one
will do, whatever it is, which isn't really correct, but ...
Still being discussed in tech-userlevel. If we wait any longer someone
is going to try the excuse that the discussion is entirely pointless, since
removing symbols is too hard.
Posted to tech-userlevel@ a week ago and reviewed by riastradh@.
GETENTROPY(3) Library Functions Manual GETENTROPY(3)
NAME
getentropy - fill a buffer with high quality random data
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
int
getentropy(void *buf, size_t buflen);
DESCRIPTION
The getentropy() function fills a buffer with high quality random data,
suitable for seeding cryptographically secure psuedorandom number
generators.
getentropy() is only intended for seeding random number generators and is
not intended for use by regular code which simply needs secure random
data. For this purpose, please use arc4random(3).
The maximum value for buflen is 256 bytes.
IMPLEMENTATION NOTES
getentropy() reads from the sysctl(7) variable kern.arandom.
RETURN VALUES
The getentropy() function returns 0 on success, and -1 if an error
occurred.
ERRORS
getentropy() will succeed unless:
[EFAULT] The buf argument points to an invalid memory address.
[EIO] Too many bytes were requested.
SEE ALSO
arc4random(3), rnd(4)
STANDARDS
The getentropy() function is non-standard.
HISTORY
The getentropy() function first appeared in OpenBSD 5.6, then in
FreeBSD 12.0, and NetBSD 10.
kernel and bootloader for 68010.
They requires a special calling convention to udivsi3, and cannot to be
mixed up in normal routines provided by libgcc or compiler_rt. Although,
there's no problem for using them in a controlled situation, i.e., kernel
and standalone programs.
Note that this does not affect at all m68k ports other than sun2, since
codes generated by gcc do not call these routines.
Assembler files are moved from common/lib/libc/arch/m68k/gen to
sys/lib/libkern/arch/m68k in order not to be compiled in libc.
Revert hack introduced to lib/libc/compiler_rt/Makefile.inc rev 1.37:
http://cvsweb.netbsd.org/bsdweb.cgi/src/lib/libc/compiler_rt/Makefile.inc#rev1.37
Proposed on port-sun2@ with no response...
(Again, this does not affect m68k ports other than sun2.)
http://mail-index.netbsd.org/port-sun2/2020/03/10/msg000102.html
rtld and libc use different storage, so the initial version would
incorrectly report the failure reason for fork().
There is still a small race condition inside ld.elf_so as it doesn't use
thread-safe errno internally, but that's a more contained internal
issue.
in a consistent state. This most importantly avoids races between dlopen
and friends and fork, potentially resulting in dead locks in the child
when it itself tries to acquire locks.
nia