I am a bit concerned. The description is trying too hard to be overly precise, and may be cumbersome for the typical reader of this page.
> Index: lib/libc/stdlib/malloc.3 > =================================================================== > RCS file: /cvs/src/lib/libc/stdlib/malloc.3,v > retrieving revision 1.78 > diff -u -p -d -r1.78 malloc.3 > --- lib/libc/stdlib/malloc.3 1 May 2014 18:41:59 -0000 1.78 > +++ lib/libc/stdlib/malloc.3 11 Jul 2014 07:19:27 -0000 > @@ -220,10 +220,23 @@ Malloc will first look for a symbolic li > .Pa /etc/malloc.conf > and next check the environment for a variable called > .Ev MALLOC_OPTIONS > +(if not > +.Xr issetugid 2 ) > and finally for the global variable > .Va malloc_options > and scan them for flags in that order. > Flags are single letters, uppercase means on, lowercase means off. > +.Pp > +The default flags are > +.Cm A > +and > +.Cm P , > +small chunks are always junked, and the first > +part of the pages is junked after free. > +The default junk behavior does not correspond to > +.Cm j > +or > +.Cm J . > .Bl -tag -width indent > .It Cm A > .Dq Abort . > @@ -271,6 +284,7 @@ Currently junk is bytes of 0xd0 when all > .Dq Duh . > \&:-) > Freed chunks are filled with 0xdf. > +This performs more junking than by default. > .It Cm j > .Dq Don't Junk . > By default, small chunks are always junked, and the first part of pages > @@ -297,6 +311,11 @@ This can substantially aid in compacting > .\"Consult the source for this one. > .It Cm S > Enable all options suitable for security auditing. > +This currently enables flags > +.Cm U , > +.Cm J , > +.Cm G > +and sets the free cache page size to 0. > .It Cm U > .Dq Free unmap . > Enable use after free protection for larger allocations. >
