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freebsd-dev/lib/libc/sys/getgroups.2

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BSD 4.4 Lite Lib Sources
1994-05-27 05:00:24 +00:00
.\" Copyright (c) 1983, 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" @(#)getgroups.2 8.2 (Berkeley) 4/16/94
$Id$ -> $FreeBSD$
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.\" $FreeBSD$
BSD 4.4 Lite Lib Sources
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.\"
getgroups(2): Remove mention of <sys/param.h> and refer to sysconf(3). Because {NGROUPS_MAX} may become variable, its value should be obtained using sysconf(3). If a #define is used anyway, it should be obtained by including <limits.h> as that is in POSIX like getgroups(2) itself is. <sys/param.h> is not in POSIX. MFC after: 1 week
2011-01-21 22:15:17 +00:00
.Dd January 21, 2011
BSD 4.4 Lite Lib Sources
1994-05-27 05:00:24 +00:00
.Dt GETGROUPS 2
mdoc(7) police: removed HISTORY info from the .Os call.
2001-07-10 13:41:46 +00:00
.Os
BSD 4.4 Lite Lib Sources
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.Sh NAME
.Nm getgroups
.Nd get group access list
Introduce ".Lb" macro to libc manpages. More libraries manpages updates following.
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.Sh LIBRARY
.Lb libc
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.Sh SYNOPSIS
mdoc(7) police: Use the new .In macro for #include statements.
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.In unistd.h
BSD 4.4 Lite Lib Sources
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.Ft int
.Fn getgroups "int gidsetlen" "gid_t *gidset"
.Sh DESCRIPTION
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe.
2002-12-18 09:22:32 +00:00
The
.Fn getgroups
system call
BSD 4.4 Lite Lib Sources
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gets the current group access list of the user process
Remove whitespace at EOL.
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and stores it in the array
BSD 4.4 Lite Lib Sources
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.Fa gidset .
mdoc(7) police: "The .Fa argument.".
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The
BSD 4.4 Lite Lib Sources
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.Fa gidsetlen
mdoc(7) police: "The .Fa argument.".
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argument
Remove whitespace at EOL.
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indicates the number of entries that may be placed in
BSD 4.4 Lite Lib Sources
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.Fa gidset .
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe.
2002-12-18 09:22:32 +00:00
The
.Fn getgroups
system call
BSD 4.4 Lite Lib Sources
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returns the actual number of groups returned in
Backed out most of rev.1.4. I didn't submit it; I only submitted a request for it something like it. It was poorly worded and too far from both POSIX wording and normal (mal)practice by referring to sysconf(_SC_NGROUPS_MAX) instead of {NGROUPS_MAX} or NGROUPS. POSIX.1 uses curly braces to mark up "symbolic constants or limits [that may be] defined in certain headers". Since we don't document this markup, don't use it. Just use NGROUPS_MAX.
1999-03-05 10:29:34 +00:00
.Fa gidset .
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
2009-06-19 15:58:24 +00:00
At least one and as many as {NGROUPS_MAX}+1 values may be returned.
Replace sys/param.h with sys/types.h as per POSIX. Document the special case of gidsetlen == 0. Partially obtained from: OpenBSD
1998-01-11 22:01:20 +00:00
If
.Fa gidsetlen
is zero,
.Fn getgroups
returns the number of supplementary group IDs associated with
the calling process without modifying the array pointed to by
.Fa gidset .
getgroups(2): Remove mention of <sys/param.h> and refer to sysconf(3). Because {NGROUPS_MAX} may become variable, its value should be obtained using sysconf(3). If a #define is used anyway, it should be obtained by including <limits.h> as that is in POSIX like getgroups(2) itself is. <sys/param.h> is not in POSIX. MFC after: 1 week
2011-01-21 22:15:17 +00:00
.Pp
The value of
.Dv {NGROUPS_MAX}
should be obtained using
.Xr sysconf 3
to avoid hard-coding it into the executable.
BSD 4.4 Lite Lib Sources
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.Sh RETURN VALUES
A successful call returns the number of groups in the group set.
A value of -1 indicates that an error occurred, and the error
code is stored in the global variable
.Va errno .
.Sh ERRORS
The possible errors for
.Fn getgroups
are:
.Bl -tag -width Er
.It Bq Er EINVAL
The argument
.Fa gidsetlen
is smaller than the number of groups in the group set.
.It Bq Er EFAULT
The argument
.Fa gidset
specifies
an invalid address.
.El
.Sh SEE ALSO
.Xr setgroups 2 ,
getgroups(2): Remove mention of <sys/param.h> and refer to sysconf(3). Because {NGROUPS_MAX} may become variable, its value should be obtained using sysconf(3). If a #define is used anyway, it should be obtained by including <limits.h> as that is in POSIX like getgroups(2) itself is. <sys/param.h> is not in POSIX. MFC after: 1 week
2011-01-21 22:15:17 +00:00
.Xr initgroups 3 ,
.Xr sysconf 3
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
2009-06-19 15:58:24 +00:00
.Sh STANDARDS
The
.Fn getgroups
system call conforms to
.St -p1003.1-2008 .
BSD 4.4 Lite Lib Sources
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.Sh HISTORY
The
Correctly use .Fn instead of .Nm to reference function names in a bunch of man pages. Use the correct .Bx (BSD UNIX) or .At (AT&T UNIX) macros instead of explicitly specifying the version in the text in a bunch of man pages.
1996-08-22 23:31:07 +00:00
.Fn getgroups
mdoc(7) police: Tidy up the syscall language. Stop calling system calls "function calls". Use "The .Fn system call" a-la "The .Nm utility". When referring to a non-BSD implementation in the HISTORY section, call syscall a function, to be safe.
2002-12-18 09:22:32 +00:00
system call appeared in
BSD 4.4 Lite Lib Sources
1994-05-27 05:00:24 +00:00
.Bx 4.2 .
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