1/*	$NetBSD$	*/
2
3/*++
4/* NAME
5/*	open_as 3
6/* SUMMARY
7/*	open file as user
8/* SYNOPSIS
9/*	#include <fcntl.h>
10/*	#include <open_as.h>
11/*
12/*	int	open_as(path, flags, mode, euid, egid)
13/*	const char *path;
14/*	int	mode;
15/*	uid_t	euid;
16/*	gid_t	egid;
17/* DESCRIPTION
18/*	open_as() opens the named \fIpath\fR with the named \fIflags\fR
19/*	and \fImode\fR, and with the effective rights specified by \fIeuid\fR
20/*	and \fIegid\fR.  A -1 result means the open failed.
21/* DIAGNOSTICS
22/*	Fatal error: no permission to change privilege level.
23/* SEE ALSO
24/*	set_eugid(3) switch effective rights
25/* LICENSE
26/* .ad
27/* .fi
28/*	The Secure Mailer license must be distributed with this software.
29/* AUTHOR(S)
30/*	Wietse Venema
31/*	IBM T.J. Watson Research
32/*	P.O. Box 704
33/*	Yorktown Heights, NY 10598, USA
34/*--*/
35
36/* System library. */
37
38#include <sys_defs.h>
39#include <fcntl.h>
40#include <unistd.h>
41
42/* Utility library. */
43
44#include "msg.h"
45#include "set_eugid.h"
46#include "open_as.h"
47
48/* open_as - open file as user */
49
50int     open_as(const char *path, int flags, int mode, uid_t euid, gid_t egid)
51{
52    uid_t   saved_euid = geteuid();
53    gid_t   saved_egid = getegid();
54    int     fd;
55
56    /*
57     * Switch to the target user privileges.
58     */
59    set_eugid(euid, egid);
60
61    /*
62     * Open that file.
63     */
64    fd = open(path, flags, mode);
65
66    /*
67     * Restore saved privileges.
68     */
69    set_eugid(saved_euid, saved_egid);
70
71    return (fd);
72}
73