Commit Graph

7 Commits

Author SHA1 Message Date
Brooks Davis
db19a093bb Remove MD __sys_* private symbols.
No references to any of these exist in the tree. The list was also
erratic with different architectures exporting different things
(arm64 and riscv exported none).

Reviewed by:	kib
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D18425
2018-12-05 00:46:09 +00:00
Mark Johnston
9f9c9b22ec Reimplement brk() and sbrk() to avoid the use of _end.
Previously, libc.so would initialize its notion of the break address
using _end, a special symbol emitted by the static linker following
the bss section.  Compatibility issues between lld and ld.bfd could
cause the wrong definition of _end (libc.so's definition rather than
that of the executable) to be used, breaking the brk()/sbrk()
interface.

Avoid this problem and future interoperability issues by simply not
relying on _end.  Instead, modify the break() system call to return
the kernel's view of the current break address, and have libc
initialize its state using an extra syscall upon the first use of the
interface.  As a side effect, this appears to fix brk()/sbrk() usage
in executables run with rtld direct exec, since the kernel and libc.so
no longer maintain separate views of the process' break address.

PR:		228574
Reviewed by:	kib (previous version)
MFC after:	2 months
Differential Revision:	https://reviews.freebsd.org/D15663
2018-06-04 19:35:15 +00:00
Brooks Davis
87385baff6 Replace MD assembly exect() with a portable version.
Originally, on the VAX exect() enable tracing once the new executable
image was loaded.  This was possible because tracing was controllable
through user space code by setting the PSL_T flag.  The following
instruction is a system call that activated tracing (as all
instructions do) by copying PSL_T to PSL_TP (trace pending).  The
first instruction of the new executable image would trigger a trace
fault.

This is not portable to all platforms and the behavior was replaced with
ptrace(PT_TRACE_ME, ...) since FreeBSD forked off of the CSRG repository.
Platforms either incorrectly call execve(), trigger trace faults inside
the original executable, or do contain an implementation of this
function.

The exect() interfaces is deprecated or removed on NetBSD and OpenBSD.

Submitted by:	Ali Mashtizadeh <ali@mashtizadeh.com>
Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D14989
2018-04-12 18:23:14 +00:00
Ed Maste
a38e4f5cc6 libc: stop exporting cerror
i386 stopped exporting .cerror in r240152, and likewise for amd64 in
r240178. It is not used by other libraries on any platform, so apply
the same change to the remaining architectures.

Reviewed by:	jhibbits, jilles
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D5774
2016-03-30 14:42:09 +00:00
Ed Maste
dae2d550d6 libc: stop exporting curbrk and minbrk in the private namespace
They are not used anywhere else in the base system and are an internal
implementation detail that does not need to be exposed.

Reviewed by:	kib
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D5728
2016-03-24 18:47:19 +00:00
David Schultz
6232589aeb Replace a proliferation of buggy MD implementations of modf() with a
working MI one.  The MI one only needs to be overridden on machines
with non-IEEE754 arithmetic.  (The last supported one was the VAX.)
It can also be overridden if someone comes up with a faster one that
actually passes the regression tests -- but this is harder than it sounds.
2011-10-21 06:40:36 +00:00
Nathan Whitehorn
840b91cc52 Provide 64-bit PowerPC support in libc.
Obtained from:	projects/ppc64
2010-07-10 14:45:03 +00:00