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Diffstat (limited to 'login-utils/login.1')
| -rw-r--r-- | login-utils/login.1 | 160 |
1 files changed, 86 insertions, 74 deletions
diff --git a/login-utils/login.1 b/login-utils/login.1 index 0e1f5eff8..92a082c67 100644 --- a/login-utils/login.1 +++ b/login-utils/login.1 @@ -1,6 +1,6 @@ .\" Copyright 1993 Rickard E. Faith (faith@cs.unc.edu) .\" May be distributed under the GNU General Public License -.TH LOGIN 1 "1 February 1993" "Linux 0.99" "Linux Programmer's Manual" +.TH LOGIN 1 "4 November 1996" "Util-linux 1.6" "Linux Programmer's Manual" .SH NAME login \- sign on .SH SYNOPSIS @@ -42,8 +42,8 @@ Failures will be logged with the facility. After these conditions are checked, the password will be requested and -checks (if a password is required for this username). Ten attempts are -allowed before +checks (if a password is required for this username). Ten attempts +are allowed before .B login dies, but after the first three, the response starts to get very slow. Login failures are reported via the @@ -52,27 +52,29 @@ facility. This facility is also used to report any successful root logins. If the file .I .hushlogin -exists, then a "quiet" login is performed (this disables the checking of -the checking of mail and the printing of the last login time and message of -the day). Otherwise, if +exists, then a "quiet" login is performed (this disables the checking +of the checking of mail and the printing of the last login time and +message of the day). Otherwise, if .I /var/log/lastlog -exists, the last login time is printed (and the current login is recorded). +exists, the last login time is printed (and the current login is +recorded). -Random administrative things, such as setting the UID and GID of the tty -are performed. The TERM environment variable is preserved, if it exists -(other environment variables are preserved if the +Random administrative things, such as setting the UID and GID of the +tty are performed. The TERM environment variable is preserved, if it +exists (other environment variables are preserved if the .B \-p option is used). Then the HOME, PATH, SHELL, TERM, MAIL, and LOGNAME environment variables are set. PATH defaults to .I /usr/local/bin:/bin:/usr/bin:. for normal users, and to .I /sbin:/bin:/usr/sbin:/usr/bin -for root. Last, if this is not a "quiet" login, the message of the day is -printed and the file with the user's name in +for root. Last, if this is not a "quiet" login, the message of the +day is printed and the file with the user's name in .I /usr/spool/mail will be checked, and a message printed if it has non-zero length. -The user's shell is then started. If no shell is specified for the user in +The user's shell is then started. If no shell is specified for the +user in .BR /etc/passwd , then .B /bin/sh @@ -102,41 +104,43 @@ Used by other servers (i.e., .BR telnetd (8)) to pass the name of the remote host to .B login -so that it may be placed in utmp and wtmp. Only the superuser may use this -option. +so that it may be placed in utmp and wtmp. Only the superuser may use +this option. .SH "SPECIAL ACCESS RESTRICTIONS" The file .I /etc/securetty -lists the names of the ttys where root is allowed to log in. One name of -a tty device without the /dev/ prefix must be specified on each line. -If the file does not exist, root is allowed to log in on any tty. +lists the names of the ttys where root is allowed to log in. One name +of a tty device without the /dev/ prefix must be specified on each +line. If the file does not exist, root is allowed to log in on any +tty. .PP The file .I /etc/usertty -specifies additional access restrictions for specific users. If this file -does not exist, no additional access restrictions are imposed. The file -consists of a sequence of sections. There are three possible section -types: CLASSES, GROUPS and USERS. A CLASSES section defines classes of -ttys and hostname patterns, A GROUPS section defines allowed ttys and -hosts on a per group basis, and a USERS section defines allowed ttys -and hosts on a per user basis. +specifies additional access restrictions for specific users. If this +file does not exist, no additional access restrictions are +imposed. The file consists of a sequence of sections. There are three +possible section types: CLASSES, GROUPS and USERS. A CLASSES section +defines classes of ttys and hostname patterns, A GROUPS section +defines allowed ttys and hosts on a per group basis, and a USERS +section defines allowed ttys and hosts on a per user basis. .PP -Each line in this file in may be no longer than 255 characters. Comments -start with # character and extend to the end of the line. +Each line in this file in may be no longer than 255 +characters. Comments start with # character and extend to the end of +the line. .PP .SS "The CLASSES Section" -A CLASSES section begins with the word CLASSES at the start of a line in all -upper case. Each following line until the start of a new section or the -end of the file consists of a sequence of words separated by tabs or -spaces. Each line defines a class of ttys and host patterns. +A CLASSES section begins with the word CLASSES at the start of a line +in all upper case. Each following line until the start of a new +section or the end of the file consists of a sequence of words +separated by tabs or spaces. Each line defines a class of ttys and +host patterns. .PP -The word at -the beginning of a line becomes defined as a collective name for the -ttys and host patterns specified at the rest of the line. This collective -name can be used in any subsequent GROUPS or USERS section. No such class -name must occur as part of the definition of a class in order to avoid -problems with recursive classes. +The word at the beginning of a line becomes defined as a collective +name for the ttys and host patterns specified at the rest of the +line. This collective name can be used in any subsequent GROUPS or +USERS section. No such class name must occur as part of the definition +of a class in order to avoid problems with recursive classes. .PP An example CLASSES section: .PP @@ -155,7 +159,7 @@ and as the corresponding right hand sides. .PP -.SS "The GROUPS Section +.SS "The GROUPS Section" A GROUPS section defines allowed ttys and hosts on a per Unix group basis. If a user is a member of a Unix group according to .I /etc/passwd @@ -184,9 +188,11 @@ stud myclass1 tty4 .PP This example specifies that members of group .I sys -may log in on tty1 and from hosts in the bar.edu domain. Users in group +may log in on tty1 and from hosts in the bar.edu domain. Users in +group .I stud -may log in from hosts/ttys specified in the class myclass1 or from tty4. +may log in from hosts/ttys specified in the class myclass1 or from +tty4. .PP .SS "The USERS Section" @@ -209,44 +215,48 @@ blue tty3 myclass2 .in -0.5 .fi .PP -This lets the user zacho login only on tty1 and from hosts with IP addreses -in the range 130.225.16.0 \- 130.225.16.255, and user blue is allowed to -log in from tty3 and whatever is specified in the class myclass2. +This lets the user zacho login only on tty1 and from hosts with IP +addreses in the range 130.225.16.0 \- 130.225.16.255, and user blue is +allowed to log in from tty3 and whatever is specified in the class +myclass2. .PP -There may be a line in a USERS section starting with a username of *. This -is a default rule and it will be applied to any user not matching any other -line. +There may be a line in a USERS section starting with a username of +*. This is a default rule and it will be applied to any user not +matching any other line. .PP -If both a USERS line and GROUPS line match a user then the user is allowed -access from the union of all the ttys/hosts mentioned in these specifications. +If both a USERS line and GROUPS line match a user then the user is +allowed access from the union of all the ttys/hosts mentioned in these +specifications. .SS Origins -The tty and host pattern specifications used in the specification of classes, -group and user access are called origins. An origin string may have -one of these formats: +The tty and host pattern specifications used in the specification of +classes, group and user access are called origins. An origin string +may have one of these formats: .IP o The name of a tty device without the /dev/ prefix, for example tty1 or ttyS0. .PP .IP o -The string @localhost, meaning that the user is allowed to telnet/rlogin -from the local host to the same host. This also allows the user to for -example run the command: xterm -e /bin/login. +The string @localhost, meaning that the user is allowed to +telnet/rlogin from the local host to the same host. This also allows +the user to for example run the command: xterm -e /bin/login. .PP .IP o A domain name suffix such as @.some.dom, meaning that the user may -rlogin/telnet from any host whose domain name has the suffix .some.dom. +rlogin/telnet from any host whose domain name has the suffix +.some.dom. .PP .IP o -A range of IPv4 addresses, written @x.x.x.x/y.y.y.y where x.x.x.x -is the IP address in the usual dotted quad decimal notation, and -y.y.y.y is a bitmask in the same notation specifying which bits in the -address to compare with the IP address of the remote host. For example +A range of IPv4 addresses, written @x.x.x.x/y.y.y.y where x.x.x.x is +the IP address in the usual dotted quad decimal notation, and y.y.y.y +is a bitmask in the same notation specifying which bits in the address +to compare with the IP address of the remote host. For example @130.225.16.0/255.255.254.0 means that the user may rlogin/telnet from -any host whose IP address is in the range 130.225.16.0 \- 130.225.17.255. +any host whose IP address is in the range 130.225.16.0 \- +130.225.17.255. .PP -Any of the above origins may be prefixed by a time specification according -to the syntax: +Any of the above origins may be prefixed by a time specification +according to the syntax: .PP .nf timespec ::= '[' <day-or-hour> [':' <day-or-hour>]* ']' @@ -256,16 +266,16 @@ hourspec ::= <hour> | <hour> '\-' <hour> day-or-hour ::= <day> | <hourspec> .fi .PP -For example, the origin [mon:tue:wed:thu:fri:8\-17]tty3 means that log in is -allowed on mondays through fridays between 8:00 and 17:59 (5:59 pm) on tty3. -This also shows that an hour range a\-b includes all moments between a:00 and -b:59. A single hour specification (such as 10) means the time span between -10:00 and 10:59. +For example, the origin [mon:tue:wed:thu:fri:8\-17]tty3 means that log +in is allowed on mondays through fridays between 8:00 and 17:59 (5:59 +pm) on tty3. This also shows that an hour range a\-b includes all +moments between a:00 and b:59. A single hour specification (such as +10) means the time span between 10:00 and 10:59. .PP -Not specifying any time prefix for a tty or host means log in from that origin -is allowed any time. If you give a time prefix be sure to specify both a set -of days and one or more hours or hour ranges. A time specification may -not include any white space. +Not specifying any time prefix for a tty or host means log in from +that origin is allowed any time. If you give a time prefix be sure to +specify both a set of days and one or more hours or hour ranges. A +time specification may not include any white space. .PP If no default rule is given then users not matching any line .I /etc/usertty @@ -292,7 +302,9 @@ are allowed to log in from anywhere as is standard behavior. .BR environ (7), .BR shutdown (8) .SH BUGS -Linux, unlike other draconian operating systems, does not check quotas. + +Linux, unlike other draconian operating systems, does not check +quotas. The undocumented BSD .B \-r @@ -300,7 +312,7 @@ option is not supported. This may be required by some .BR rlogind (8) programs. .SH AUTHOR -Derived from BSD login 5.40 (5/9/89) by Michael Glad (glad@daimi.dk) for HP-UX +Derived from BSD login 5.40 (5/9/89) by Michael Glad (glad@daimi.dk) +for HP-UX .br Ported to Linux 0.12: Peter Orbaek (poe@daimi.aau.dk) - |