1/* Part of SWI-Prolog 2 3 Author: Jan Wielemaker 4 E-mail: J.Wielemaker@vu.nl 5 WWW: http://www.swi-prolog.org 6 Copyright (c) 2011-2013, VU University Amsterdam 7 All rights reserved. 8 9 Redistribution and use in source and binary forms, with or without 10 modification, are permitted provided that the following conditions 11 are met: 12 13 1. Redistributions of source code must retain the above copyright 14 notice, this list of conditions and the following disclaimer. 15 16 2. Redistributions in binary form must reproduce the above copyright 17 notice, this list of conditions and the following disclaimer in 18 the documentation and/or other materials provided with the 19 distribution. 20 21 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 29 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 31 ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 32 POSSIBILITY OF SUCH DAMAGE. 33*/ 34 35:- module(uid, 36 [ getuid/1, % -UID 37 getgid/1, % -GID 38 geteuid/1, % -UID 39 getegid/1, % -GID 40 getgroups/1, % -GIDs 41 user_info/2, % +User, -UserInfo 42 group_info/2, % +Group, -GroupInfo 43 user_data/3, % +Field, +UserInfo, -Value 44 group_data/3, % +Field, +GroupInfo, -Value 45 setuid/1, % +UID 46 setgid/1, % +GID 47 seteuid/1, % +UID 48 setegid/1, % +GID 49 50 set_user_and_group/1, % +User 51 set_user_and_group/2 % +User, +Group 52 ]). 53 54:- use_foreign_library(foreign(uid)). 55 56:- if(predicate_property(initgroups(_,_), defined)). 57:- export(initgroups/2). 58:- else. 59initgroups(_,_). 60:- endif. 61 62:- if(predicate_property(setgroups(_), defined)). 63:- export(setgroups/1). 64:- endif. 65 66/** <module> User and group management on Unix systems 67 68This module provides and interface to user and group information on 69Posix systems. In addition, it allows for changing user and group ids. 70When changing user and group settings for the calling process, bear in 71mind that: 72 73 - Changing user and groups of the calling process requires permission. 74 - The functions setgroups() and initgroups() are not part of the 75 POSIX standard and therefore the derived predicates may not be 76 present. 77 78@see Please check the documentation of your OS for details on the 79 semantics of this predicates. 80*/ 81 82%! getuid(-UID) is det. 83% 84% UID is the real user ID of the calling process. 85 86%! getgid(-GID) is det. 87% 88% GID is the real group ID of the calling process. 89 90%! geteuid(-UID) is det. 91% 92% UID is the effective user ID of the calling process. 93 94%! getegid(-GID) is det. 95% 96% GID is the effective group ID of the calling process. 97 98%! getgroups(-GroupsIDs:list(integer)) is det. 99% 100% GroupsIDs is the set of supplementary group IDs of the calling 101% process. Note that these are numeric identifiers. Use 102% group_info/2 to obtain details on the returned group 103% identifiers. 104 105%! user_info(+User, -UserData) is det. 106% 107% UserData represent the passwd information for User. User is 108% either a numeric UID or a user name. The predicate user_data/3 109% can be used to extract information from UserData. 110 111%! user_data(?Field, ?UserData, ?Value) 112% 113% Value is the value for Field in UserData. Defined fields are: 114% 115% * name 116% Name of the user 117% * password 118% Password hash of the user (or =x= if this is not accessible) 119% * uid 120% Numeric user id of the user 121% * gid 122% Numeric primary group id of the user 123% * comment 124% The _gecos_ field 125% * home 126% Home directory of the user 127% * shell 128% Default (login) shell of the user. 129 130user_data(name, user_info(Nam, _, _, _, _, _, _), Nam). 131user_data(password, user_info(_, PWD, _, _, _, _, _), PWD). 132user_data(uid, user_info(_, _, UID, _, _, _, _), UID). 133user_data(gid, user_info(_, _, _, GID, _, _, _), GID). 134user_data(comment, user_info(_, _, _, _, GEC, _, _), GEC). 135user_data(home, user_info(_, _, _, _, _, HOM, _), HOM). 136user_data(shell, user_info(_, _, _, _, _, _, SHE), SHE). 137 138%! group_info(+Group, -GroupData) is det. 139% 140% GroupData represent the group information for Group. Group is 141% either a numeric GID or a group name. The predicate group_data/3 142% can be used to extract information from GroupData. 143 144%! group_data(?Field, ?GroupData, ?Value) 145% 146% Value is the value for Field GroupData. Defined fields are: 147% 148% * name 149% Name of the user 150% * password 151% Password hash of the user (or =x= if this is not accessible) 152% * gid 153% Numeric group id of the group 154% * members 155% List of user-names that are member of this group. 156 157group_data(name, group_info(Nam, _, _, _), Nam). 158group_data(password, group_info(_, PWD, _, _), PWD). 159group_data(gid, group_info(_, _, GID, _), GID). 160group_data(members, group_info(_, _, _, MBR), MBR). 161 162 /******************************* 163 * SETTING * 164 *******************************/ 165 166%! setuid(+UID) 167% 168% Set the user id of the calling process. 169 170%! seteuid(+UID) 171% 172% Set the effective user id of the calling process. 173 174 175%! setgid(+GID) 176% 177% Set the group id of the calling process. 178 179%! setegid(+GID) 180% 181% Set the effective group id of the calling process. 182 183%! initgroups(+User, +Group) is det. 184% 185% Initialise the group access list of the calling process to the 186% registered groups for User and the group Group. This predicate 187% is only available if the underlying OS provides it. 188 189%! setgroups(+Groups:list(integer)) is det. 190% 191% Set the group access list of the caling process to the indicated 192% groups. This predicate is only available if the underlying OS 193% provides it. 194 195%! set_user_and_group(+User) is det. 196%! set_user_and_group(+User, +Group) is det. 197% 198% Set the UID and GID to the User. User is either a UID or a user 199% name. If Group is not specified, the primary group of User is 200% used. If initgroups/2 is available, the resulting group access 201% list of the calling process consists of the registered groups 202% for User and the specified Group. 203 204set_user_and_group(User) :- 205 user_info(User, Data), 206 user_data(uid, Data, UID), 207 user_data(gid, Data, GID), 208 initgroups(User, GID), 209 setgid(GID), 210 setuid(UID). 211 212set_user_and_group(User, Group) :- 213 user_info(User, Data), 214 group_info(Group, GData), 215 user_data(uid, Data, UID), 216 user_data(gid, Data, UGID), 217 group_data(gid, GData, GID), 218 initgroups(User, UGID), 219 setgid(GID), 220 setuid(UID).