The new wording for standard flags is losely based on the POSIX
description.
Make it clearer that PROT_MAX() is a local extension.
Reviewed by: alc, mckusick, imp, kib, markj
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D31777
This text dates to the BSD 4.4 import and is misleading. The mprotect
syscall acts on page granularity and breaks up mappings as required to
do so.
Note that with the addition of non-transparent superpages (aka
largepages) the size of a page at a given address may vary. This
commit does not attempt to address the lack of documentation of this
feature.
Sponsored by: DARPA
Reviewed by: alc, mckusick, imp, kib, markj
Differential Revision: https://reviews.freebsd.org/D31776
From POSIX,
[ENOTSUP]
The implementation does not support the combination of accesses
requested in the prot argument.
This fits the case that prot contains permissions which are not a subset
of prot_max.
Reviewed by: brooks, cem
Relnotes: Yes
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D23843
In the case of mmap(), add a HISTORY section. Mention that mmap() and
mprotect()'s documentation predates an implementation. The
implementation first saw wide use in 4.3-Reno, but there seems to be no
easy way to express that in mdoc so stick with 4.4BSD.
Reviewed by: emaste
Requested by: cem
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D20713
A new macro PROT_MAX() alters a protection value so it can be OR'd with
a regular protection value to specify the maximum permissions. If
present, these flags specify the maximum permissions.
While these flags are non-portable, they can be used in portable code
with simple ifdefs to expand PROT_MAX() to 0.
This change allows (e.g.) a region that must be writable during run-time
linking or JIT code generation to be made permanently read+execute after
writes are complete. This complements W^X protections allowing more
precise control by the programmer.
This change alters mprotect argument checking and returns an error when
unhandled protection flags are set. This differs from POSIX (in that
POSIX only specifies an error), but is the documented behavior on Linux
and more closely matches historical mmap behavior.
In addition to explicit setting of the maximum permissions, an
experimental sysctl vm.imply_prot_max causes mmap to assume that the
initial permissions requested should be the maximum when the sysctl is
set to 1. PROT_NONE mappings are excluded from this for compatibility
with rtld and other consumers that use such mappings to reserve
address space before mapping contents into part of the reservation. A
final version this is expected to provide per-binary and per-process
opt-in/out options and this sysctl will go away in its current form.
As such it is undocumented.
Reviewed by: emaste, kib (prior version), markj
Additional suggestions from: alc
Obtained from: CheriBSD
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D18880
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.
Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96
Our mprotect() function seems to take a "const void *" address to the
pages whose permissions need to be adjusted. POSIX uses "void *". Simply
stick to the POSIX one to prevent us from writing unportable code.
PR: 211423 (exp-run)
Tested by: antoine@ (Thanks!)
Stop calling system calls "function calls".
Use "The .Fn system call" a-la "The .Nm utility".
When referring to a non-BSD implementation in
the HISTORY section, call syscall a function,
to be safe.
track.
The $Id$ line is normally at the bottom of the main comment block in the
man page, separated from the rest of the manpage by an empty comment,
like so;
.\" $Id$
.\"
If the immediately preceding comment is a @(#) format ID marker than the
the $Id$ will line up underneath it with no intervening blank lines.
Otherwise, an additional blank line is inserted.
Approved by: bde
mlock, mmap, mprotect, msync, munlock, and munmap are defined by
POSIX as taking void *. The const modifier has been added to
mlock, munlock, and mprotect as the standard dictates.
minherit comes from OpenBSD and has been updated to conform with
their recent change to void *.
madvise and mincore are not defined by POSIX, but their arguments
have been modified to be consistent with the POSIX-defined functions.
mincore takes a const pointer, but madvise does not due to the
MADV_FREE case.
Discussed with: bde
in a bunch of man pages.
Use the correct .Bx (BSD UNIX) or .At (AT&T UNIX) macros
instead of explicitly specifying the version in the text
in a bunch of man pages.
