runuser: new command (derived from su(1))

 This command is based on su(1), the differences:

 - based on Fedora runuser su(1) patch
 - not installed with suid rights
 - allowed for root users only
 - don't ask for password
 - uses PAM session, for example:

$ cat /etc/pam.d/runuser
auth		sufficient	pam_rootok.so
session		optional	pam_keyinit.so revoke
session		required	pam_limits.so
session		required	pam_unix.so

$ cat /etc/pam.d/runuser-l
auth		include		runuser
session		optional	pam_keyinit.so force revoke
session		include		runuser

Signed-off-by: Karel Zak <kzak@redhat.com>

1 files changed, 230 insertions, 0 deletions

diff --git a/login-utils/runuser.1 b/login-utils/runuser.1
new file mode 100644
index 000000000..66ad1c48f
--- /dev/null
+++ b/login-utils/runuser.1
@@ -0,0 +1,230 @@
+.TH RUNUSER "1" "August 2012" "util-linux" "User Commands"
+.SH NAME
+runuser \- run a command with substitute user and group ID
+.SH SYNOPSIS
+.B runuser
+[options...] [\-] [user [args...]]
+.SH DESCRIPTION
+.B runuser
+allows to run commands with substitute user and group ID.
+The difference between the commands
+.B runuser
+and
+.B su
+is that
+.B runuser
+does not ask for password, because it may be executed by root user only.
+The command
+.B runuser
+does not have to be installed with suid permissions.
+.PP
+When called without arguments
+.B runuser
+defaults to running an interactive shell as
+.IR root .
+.PP
+For backward compatibility
+.B runuser
+defaults to not change the current directory and to only set the
+environment variables
+.B HOME
+and
+.B SHELL
+(plus
+.B USER
+and
+.B LOGNAME
+if the target
+.I user
+is not root).  It is recommended to always use the
+.B \-\-login
+option (instead it's shortcut
+.BR \- )
+to avoid side effects caused by mixing environments.
+.PP
+This version of
+.B runuser
+uses PAM for session management.
+.SH OPTIONS
+.TP
+\fB\-c\fR \fIcommand\fR, \fB\-\-command\fR=\fIcommand\fR
+Pass
+.I command
+to the shell with the
+.B \-c
+option.
+.TP
+\fB\-\-session\-command\fR=\fIcommand\fR
+Same as
+.B \-c
+but do not create a new session (discouraged).
+.TP
+\fB\-f\fR, \fB\-\-fast\fR
+Pass
+.B \-f
+to the shell which may or may not be useful depending on the
+shell.
+.TP
+\fB\-g\fR, \fB\-\-group\fR=\fIgroup\fR\fR
+specify the primary group, this option is allowed for root user only
+.TP
+\fB\-G\fR, \fB\-\-supp-group\fR=\fIgroup\fR\fR
+specify a supplemental group, this option is allowed for root user only
+.TP
+\fB\-\fR, \fB\-l\fR, \fB\-\-login\fR
+Starts the shell as login shell with an environment similar to a real
+login:
+.RS 10
+.TP
+o
+clears all environment variables except for
+.B TERM
+.TP
+o
+initializes the environment variables
+.BR HOME ,
+.BR SHELL ,
+.BR USER ,
+.BR LOGNAME ,
+.B PATH
+.TP
+o
+changes to the target user's home directory
+.TP
+o
+sets argv[0] of the shell to
+.RB ' \- '
+in order to make the shell a login shell
+.RE
+.TP
+\fB\-m\fR, \fB\-p\fR, \fB\-\-preserve-environment\fR
+Preserves the whole environment, ie does not set
+.BR HOME ,
+.BR SHELL ,
+.B USER
+nor
+.BR LOGNAME .
+.TP
+\fB\-s\fR \fISHELL\fR, \fB\-\-shell\fR=\fISHELL\fR
+Runs the specified shell instead of the default.  The shell to run is
+selected according to the following rules in order:
+.RS 10
+.TP
+o
+the shell specified with
+.B \-\-shell
+.TP
+o
+The shell specified in the environment variable
+.B SHELL
+if the
+.B \-\-preserve-environment
+option is used.
+.TP
+o
+the shell listed in the passwd entry of the target user
+.TP
+o
+/bin/sh
+.RE
+.IP
+If the target user has a restricted shell (i.e. not listed in
+/etc/shells) the
+.B \-\-shell
+option and the
+.B SHELL
+environment variables are ignored unless the calling user is root.
+.TP
+\fB\-\-help\fR
+Display help text and exit.
+.TP
+\fB\-\-version\fR
+Display version information and exit.
+.SH CONFIG FILES
+.B runuser
+reads the
+.I /etc/default/runuser
+and
+.I /etc/login.defs
+configuration files.  The following configuration items are relevant
+for
+.BR runuser :
+.PP
+.B ENV_PATH
+(string)
+.RS 4
+Defines the PATH environment variable for a regular user.  The
+default value is
+.IR /usr/local/bin:\:/bin:\:/usr/bin .
+.RE
+.PP
+.B ENV_ROOTPATH
+(string)
+.br
+.B ENV_SUPATH
+(string)
+.RS 4
+Defines the PATH environment variable for root. The default value is
+.IR /usr/local/sbin:\:/usr/local/bin:\:/sbin:\:/bin:\:/usr/sbin:\:/usr/bin .
+.RE
+.PP
+.B ALWAYS_SET_PATH
+(boolean)
+.RS 4
+If set to
+.I yes
+and \-\-login and \-\-preserve\-environment were not specified
+.B runuser
+initializes
+.BR PATH .
+.RE
+.SH EXIT STATUS
+.B runuser
+normally returns the exit status of the command it executed.  If the
+command was killed by a signal,
+.B runuser
+returns the number of the signal plus 128.
+.PP
+Exit status generated by
+.B runuser
+itself:
+.RS 10
+.TP
+1
+Generic error before executing the requested command
+.TP
+126
+The requested command could not be executed
+.TP
+127
+The requested command could was not found
+.RE
+.SH FILES
+.PD 0
+.TP 17
+/etc/pam.d/runuser
+default PAM configuration file
+.TP
+/etc/pam.d/runuser-l
+PAM configuration file if \-\-login is specified
+.TP
+/etc/default/runuser
+runuser specific logindef config file
+.TP
+/etc/login.defs
+global logindef config file
+.PD 1
+.SH "SEE ALSO"
+.BR pam (8),
+.BR shells (5),
+.BR login.defs (5),
+.BR su (1)
+.SH AUTHOR
+Derived from coreutils' su which was based on an implemenation from
+David MacKenzie and Fedora runuser command from Dan Walsh.
+.SH AVAILABILITY
+The runuser command is part of the util-linux package and is
+available from
+.UR ftp://\:ftp.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
+Linux Kernel Archive
+.UE .