From da4e70cf9ab3e05f67d77de37a7c6c335a5f7e4b Mon Sep 17 00:00:00 2001
From: brooks <brooks@FreeBSD.org>
Date: Fri, 19 Jun 2009 15:58:24 +0000
Subject: In preparation for raising NGROUPS and NGROUPS_MAX, change base
 system callers of getgroups(), getgrouplist(), and setgroups() to allocate
 buffers dynamically.  Specifically, allocate a buffer of size
 sysconf(_SC_NGROUPS_MAX)+1 (+2 in a few cases to allow for overflow).

This (or similar gymnastics) is required for the code to actually follow
the POSIX.1-2008 specification where {NGROUPS_MAX} may differ at runtime
and where getgroups may return {NGROUPS_MAX}+1 results on systems like
FreeBSD which include the primary group.

In id(1), don't pointlessly add the primary group to the list of all
groups, it is always the first result from getgroups().  In principle
the old code was more portable, but this was only done in one of the two
places where getgroups() was called to the overall effect was pointless.

Document the actual POSIX requirements in the getgroups(2) and
setgroups(2) manpages.  We do not yet support a dynamic NGROUPS, but we
may in the future.

MFC after:	2 weeks
---
 lib/libc/sys/getgroups.2 | 10 ++++++----
 lib/libc/sys/setgroups.2 |  6 ++----
 2 files changed, 8 insertions(+), 8 deletions(-)

(limited to 'lib/libc/sys')

diff --git a/lib/libc/sys/getgroups.2 b/lib/libc/sys/getgroups.2
index 5eadfe1..4fd8fee 100644
--- a/lib/libc/sys/getgroups.2
+++ b/lib/libc/sys/getgroups.2
@@ -58,10 +58,7 @@ The
 system call
 returns the actual number of groups returned in
 .Fa gidset .
-No more than
-.Dv NGROUPS_MAX
-will ever
-be returned.
+At least one and as many as {NGROUPS_MAX}+1 values may be returned.
 If
 .Fa gidsetlen
 is zero,
@@ -92,6 +89,11 @@ an invalid address.
 .Sh SEE ALSO
 .Xr setgroups 2 ,
 .Xr initgroups 3
+.Sh STANDARDS
+The
+.Fn getgroups
+system call conforms to
+.St -p1003.1-2008 .
 .Sh HISTORY
 The
 .Fn getgroups
diff --git a/lib/libc/sys/setgroups.2 b/lib/libc/sys/setgroups.2
index e56e95f..ef4c34c 100644
--- a/lib/libc/sys/setgroups.2
+++ b/lib/libc/sys/setgroups.2
@@ -53,9 +53,7 @@ The
 argument
 indicates the number of entries in the array and must be no
 more than
-.Dv NGROUPS ,
-as defined in
-.In sys/param.h .
+.Dv {NGROUPS_MAX}+1 .
 .Pp
 Only the super-user may set a new group list.
 .Sh RETURN VALUES
@@ -71,7 +69,7 @@ The caller is not the super-user.
 The number specified in the
 .Fa ngroups
 argument is larger than the
-.Dv NGROUPS
+.Dv {NGROUPS_MAX}+1
 limit.
 .It Bq Er EFAULT
 The address specified for
-- 
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