uid.pl -- User and group management on Unix systems
This module provides and interface to user and group information on
Posix systems. In addition, it allows for changing user and group ids.
When changing user and group settings for the calling process, bear in
mind that:
- Changing user and groups of the calling process requires permission.
- The functions
setgroups() and initgroups() are not part of the
POSIX standard and therefore the derived predicates may not be
present.
- See also
- - Please check the documentation of your OS for details on the
semantics of this predicates.
- getuid(-UID) is det
- UID is the real user ID of the calling process.
- getgid(-GID) is det
- GID is the real group ID of the calling process.
- geteuid(-UID) is det
- UID is the effective user ID of the calling process.
- getegid(-GID) is det
- GID is the effective group ID of the calling process.
- getgroups(-GroupsIDs:list(integer)) is det
- GroupsIDs is the set of supplementary group IDs of the calling
process. Note that these are numeric identifiers. Use
group_info/2 to obtain details on the returned group
identifiers.
- user_info(+User, -UserData) is det
- UserData represent the passwd information for User. User is
either a numeric UID or a user name. The predicate user_data/3
can be used to extract information from UserData.
- user_data(?Field, ?UserData, ?Value)
- Value is the value for Field in UserData. Defined fields are:
- name
- Name of the user
- password
- Password hash of the user (or
x if this is not accessible)
- uid
- Numeric user id of the user
- gid
- Numeric primary group id of the user
- comment
- The gecos field
- home
- Home directory of the user
- shell
- Default (login) shell of the user.
- group_info(+Group, -GroupData) is det
- GroupData represent the group information for Group. Group is
either a numeric GID or a group name. The predicate group_data/3
can be used to extract information from GroupData.
- group_data(?Field, ?GroupData, ?Value)
- Value is the value for Field GroupData. Defined fields are:
- name
- Name of the user
- password
- Password hash of the user (or
x if this is not accessible)
- gid
- Numeric group id of the group
- members
- List of user-names that are member of this group.
- setuid(+UID)
- Set the user id of the calling process.
- seteuid(+UID)
- Set the effective user id of the calling process.
- setgid(+GID)
- Set the group id of the calling process.
- setegid(+GID)
- Set the effective group id of the calling process.
- initgroups(+User, +Group) is det
- Initialise the group access list of the calling process to the
registered groups for User and the group Group. This predicate
is only available if the underlying OS provides it.
- setgroups(+Groups:list(integer)) is det
- Set the group access list of the caling process to the indicated
groups. This predicate is only available if the underlying OS
provides it.
- set_user_and_group(+User) is det
- set_user_and_group(+User, +Group) is det
- Set the UID and GID to the User. User is either a UID or a user
name. If Group is not specified, the primary group of User is
used. If initgroups/2 is available, the resulting group access
list of the calling process consists of the registered groups
for User and the specified Group.