From decd9992044001d623fd41905900579c7939570f Mon Sep 17 00:00:00 2001
From: brooks <brooks@ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f>
Date: Thu, 31 May 2018 16:10:44 +0000
Subject: [PATCH] MFC r292268, r334176
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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


git-svn-id: svn://svn.freebsd.org/base/stable/10@334440 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
---
 lib/libc/sys/brk.2    | 18 ++++++++++++++++--
 lib/libc/sys/getgid.2 |  3 +--
 lib/libc/sys/getpid.2 |  3 +--
 lib/libc/sys/read.2   |  3 +--
 lib/libc/sys/write.2  |  3 +--
 5 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/lib/libc/sys/brk.2 b/lib/libc/sys/brk.2
index 31dea32a0..0eb61d582 100644
--- a/lib/libc/sys/brk.2
+++ b/lib/libc/sys/brk.2
@@ -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.
diff --git a/lib/libc/sys/getgid.2 b/lib/libc/sys/getgid.2
index b03040bdf..5bd2a94b9 100644
--- a/lib/libc/sys/getgid.2
+++ b/lib/libc/sys/getgid.2
@@ -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
diff --git a/lib/libc/sys/getpid.2 b/lib/libc/sys/getpid.2
index aefa7708e..ab69f7117 100644
--- a/lib/libc/sys/getpid.2
+++ b/lib/libc/sys/getpid.2
@@ -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
diff --git a/lib/libc/sys/read.2 b/lib/libc/sys/read.2
index e99665fa6..a0a7be838 100644
--- a/lib/libc/sys/read.2
+++ b/lib/libc/sys/read.2
@@ -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"
diff --git a/lib/libc/sys/write.2 b/lib/libc/sys/write.2
index a06e7c9d8..0bfe56530 100644
--- a/lib/libc/sys/write.2
+++ b/lib/libc/sys/write.2
@@ -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"
-- 
2.42.0