svn commit: r334440 - stable/10/lib/libc/sys

[Brooks Davis]

Author: brooks
Date: Thu May 31 16:10:44 2018
New Revision: 334440
URL: https://svnweb.freebsd.org/changeset/base/334440

Log:
  MFC r292268, r334176
  
  r292268:
  Remove sys/types.h due to STANDARDS and unistd.h also includes
  sys/types.h.
  
  r334176:
  Indicate the brk/sbrk are deprecated and not portable.
  
  More firmly suggest mmap(2) instead.
  
  Include the history of arm64 and riscv shipping without brk/sbrk.
  
  Mention that sbrk(0) produces unreliable results.
  
  Reviewed by:	emaste, Marcin Cieślak
  Sponsored by:	DARPA, AFRL
  Differential Revision:	https://reviews.freebsd.org/D15535

Modified:
  stable/10/lib/libc/sys/brk.2
  stable/10/lib/libc/sys/getgid.2
  stable/10/lib/libc/sys/getpid.2
  stable/10/lib/libc/sys/read.2
  stable/10/lib/libc/sys/write.2
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/lib/libc/sys/brk.2
==============================================================================
--- stable/10/lib/libc/sys/brk.2	Thu May 31 16:01:10 2018	(r334439)
+++ stable/10/lib/libc/sys/brk.2	Thu May 31 16:10:44 2018	(r334440)
@@ -28,7 +28,7 @@
 .\"     @(#)brk.2	8.4 (Berkeley) 5/1/95
 .\" $FreeBSD$
 .\"
-.Dd July 12, 1999
+.Dd May 24, 2018
 .Dt BRK 2
 .Os
 .Sh NAME
@@ -38,7 +38,6 @@
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
-.In sys/types.h
 .In unistd.h
 .Ft int
 .Fn brk "const void *addr"
@@ -52,6 +51,10 @@ and
 .Fn sbrk
 functions are legacy interfaces from before the
 advent of modern virtual memory management.
+They are deprecated and not present on the arm64 or riscv architectures.
+The
+.Xr mmap 2
+interface should be used to allocate pages instead.
 .Ef
 .Pp
 The
@@ -153,6 +156,11 @@ The
 .Fn brk
 function appeared in
 .At v7 .
+.Fx 11.0
+introduced the arm64 and riscv architectures which do not support
+.Fn brk
+or
+.Fn sbrk .
 .Sh BUGS
 Mixing
 .Fn brk
@@ -169,3 +177,9 @@ It is not possible to distinguish this
 from a failure caused by exceeding the maximum size of
 the data segment without consulting
 .Xr getrlimit 2 .
+.Pp
+.Fn sbrk
+is sometimes used to monitor heap use by calling with an argument of 0.
+The result is unlikely to reflect actual utilization in combination with an
+.Xr mmap 2
+based malloc.

Modified: stable/10/lib/libc/sys/getgid.2
==============================================================================
--- stable/10/lib/libc/sys/getgid.2	Thu May 31 16:01:10 2018	(r334439)
+++ stable/10/lib/libc/sys/getgid.2	Thu May 31 16:10:44 2018	(r334440)
@@ -28,7 +28,7 @@
 .\"     @(#)getgid.2	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd June 4, 1993
+.Dd December 15, 2015
 .Dt GETGID 2
 .Os
 .Sh NAME
@@ -38,7 +38,6 @@
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
-.In sys/types.h
 .In unistd.h
 .Ft gid_t
 .Fn getgid void

Modified: stable/10/lib/libc/sys/getpid.2
==============================================================================
--- stable/10/lib/libc/sys/getpid.2	Thu May 31 16:01:10 2018	(r334439)
+++ stable/10/lib/libc/sys/getpid.2	Thu May 31 16:10:44 2018	(r334440)
@@ -28,7 +28,7 @@
 .\"     @(#)getpid.2	8.1 (Berkeley) 6/4/93
 .\" $FreeBSD$
 .\"
-.Dd November 2, 2006
+.Dd December 15, 2015
 .Dt GETPID 2
 .Os
 .Sh NAME
@@ -38,7 +38,6 @@
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
-.In sys/types.h
 .In unistd.h
 .Ft pid_t
 .Fn getpid void

Modified: stable/10/lib/libc/sys/read.2
==============================================================================
--- stable/10/lib/libc/sys/read.2	Thu May 31 16:01:10 2018	(r334439)
+++ stable/10/lib/libc/sys/read.2	Thu May 31 16:10:44 2018	(r334440)
@@ -28,7 +28,7 @@
 .\"     @(#)read.2	8.4 (Berkeley) 2/26/94
 .\" $FreeBSD$
 .\"
-.Dd September 11, 2013
+.Dd December 15, 2015
 .Dt READ 2
 .Os
 .Sh NAME
@@ -40,7 +40,6 @@
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
-.In sys/types.h
 .In unistd.h
 .Ft ssize_t
 .Fn read "int fd" "void *buf" "size_t nbytes"

Modified: stable/10/lib/libc/sys/write.2
==============================================================================
--- stable/10/lib/libc/sys/write.2	Thu May 31 16:01:10 2018	(r334439)
+++ stable/10/lib/libc/sys/write.2	Thu May 31 16:10:44 2018	(r334440)
@@ -28,7 +28,7 @@
 .\"     @(#)write.2	8.5 (Berkeley) 4/2/94
 .\" $FreeBSD$
 .\"
-.Dd September 11, 2013
+.Dd December 15, 2015
 .Dt WRITE 2
 .Os
 .Sh NAME
@@ -40,7 +40,6 @@
 .Sh LIBRARY
 .Lb libc
 .Sh SYNOPSIS
-.In sys/types.h
 .In unistd.h
 .Ft ssize_t
 .Fn write "int fd" "const void *buf" "size_t nbytes"