mremap: Update manual entry

Update mremap manual entry:

1. Change mremap to variadic.
2. Document MREMAP_FIXED and MREMAP_DONTUNMAP.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit cb2dee4ecc)
This commit is contained in:
H.J. Lu 2024-07-24 14:05:14 -07:00 committed by Florian Weimer
parent 3433a35842
commit 2eb2d78ca7
2 changed files with 36 additions and 7 deletions

1
NEWS
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@ -10,6 +10,7 @@ Version 2.40.1
The following bugs are resolved with this release:
[30081] resolv: Do not wait for non-existing second DNS response after error
[31968] mremap implementation in C does not handle arguments correctly
[31890] resolv: Allow short error responses to match any DNS query
[31968] mremap implementation in C does not handle arguments correctly

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@ -1892,7 +1892,7 @@ There is no existing mapping in at least part of the given region.
@end deftypefun
@deftypefun {void *} mremap (void *@var{address}, size_t @var{length}, size_t @var{new_length}, int @var{flag})
@deftypefun {void *} mremap (void *@var{address}, size_t @var{length}, size_t @var{new_length}, int @var{flag}, ... /* void *@var{new_address} */)
@standards{GNU, sys/mman.h}
@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
@ -1901,12 +1901,40 @@ area. @var{address} and @var{length} must cover a region entirely mapped
in the same @code{mmap} statement. A new mapping with the same
characteristics will be returned with the length @var{new_length}.
One option is possible, @code{MREMAP_MAYMOVE}. If it is given in
@var{flags}, the system may remove the existing mapping and create a new
one of the desired length in another location.
Possible flags are
The address of the resulting mapping is returned, or @math{-1}. Possible
error codes include:
@table @code
@item MREMAP_MAYMOVE
If it is given in @var{flags}, the system may remove the existing mapping
and create a new one of the desired length in another location.
@item MREMAP_FIXED
If it is given in @var{flags}, @code{mremap} accepts a fifth argument,
@code{void *new_address}, which specifies a page-aligned address to
which the mapping must be moved. Any previous mapping at the address
range specified by @var{new_address} and @var{new_size} is unmapped.
@code{MREMAP_FIXED} must be used together with @code{MREMAP_MAYMOVE}.
@item MREMAP_DONTUNMAP
If it is given in @var{flags}, @code{mremap} accepts a fifth argument,
@code{void *new_address}, which specifies a page-aligned address. Any
previous mapping at the address range specified by @var{new_address} and
@var{new_size} is unmapped. If @var{new_address} is @code{NULL}, the
kernel chooses the page-aligned address at which to create the mapping.
Otherwise, the kernel takes it as a hint about where to place the mapping.
The mapping at the address range specified by @var{old_address} and
@var{old_size} isn't unmapped.
@code{MREMAP_DONTUNMAP} must be used together with @code{MREMAP_MAYMOVE}.
@var{old_size} must be the same as @var{new_size}. This flag bit is
Linux-specific.
@end table
The address of the resulting mapping is returned, or @code{MAP_FAILED}.
Possible error codes include:
@table @code
@ -1915,7 +1943,7 @@ There is no existing mapping in at least part of the original region, or
the region covers two or more distinct mappings.
@item EINVAL
The address given is misaligned or inappropriate.
Any arguments are inappropriate, including unknown @var{flags} values.
@item EAGAIN
The region has pages locked, and if extended it would exceed the