| | 1 | .\" $NetBSD: getlogin.2,v 1.4 1995/02/27 12:33:03 cgd Exp $ |
| | 2 | .\" |
| | 3 | .\" Copyright (c) 1989, 1991, 1993 |
| | 4 | .\" The Regents of the University of California. All rights reserved. |
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| | 8 | .\" are met: |
| | 9 | .\" 1. Redistributions of source code must retain the above copyright |
| | 10 | .\" notice, this list of conditions and the following disclaimer. |
| | 11 | .\" 2. Redistributions in binary form must reproduce the above copyright |
| | 12 | .\" notice, this list of conditions and the following disclaimer in the |
| | 13 | .\" documentation and/or other materials provided with the distribution. |
| | 14 | .\" 3. All advertising materials mentioning features or use of this software |
| | 15 | .\" must display the following acknowledgement: |
| | 16 | .\" This product includes software developed by the University of |
| | 17 | .\" California, Berkeley and its contributors. |
| | 18 | .\" 4. Neither the name of the University nor the names of its contributors |
| | 19 | .\" may be used to endorse or promote products derived from this software |
| | 20 | .\" without specific prior written permission. |
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| | 22 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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| | 24 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| | 34 | .\" @(#)getlogin.2 8.1 (Berkeley) 6/9/93 |
| | 35 | .\" |
| | 36 | .Dd June 9, 1993 |
| | 37 | .Dt GETLOGIN 2 |
| | 38 | .Os BSD 4.2 |
| | 39 | .Sh NAME |
| | 40 | .Nm getlogin , |
| | 41 | .Nm setlogin |
| | 42 | .Nd get/set login name |
| | 43 | .Sh SYNOPSIS |
| | 44 | .Fd #include <unistd.h> |
| | 45 | .Ft char * |
| | 46 | .Fo getlogin |
| | 47 | .Fa void |
| | 48 | .Fc |
| | 49 | .Ft int |
| | 50 | .Fo setlogin |
| | 51 | .Fa "const char *name" |
| | 52 | .Fc |
| | 53 | .Sh DESCRIPTION |
| | 54 | The |
| | 55 | .Fn getlogin |
| | 56 | routine |
| | 57 | returns the login name of the user associated with the current session, |
| | 58 | as previously set by |
| | 59 | .Fn setlogin . |
| | 60 | The name is normally associated with a login shell |
| | 61 | at the time a session is created, |
| | 62 | and is inherited by all processes descended from the login shell. |
| | 63 | (This is true even if some of those processes assume another user ID, |
| | 64 | for example when |
| | 65 | .Xr su 1 |
| | 66 | is used.) |
| | 67 | .Pp |
| | 68 | .Fn setlogin |
| | 69 | sets the login name of the user associated with the current session to |
| | 70 | .Fa name . |
| | 71 | This call is restricted to the super-user, and |
| | 72 | is normally used only when a new session is being created on behalf |
| | 73 | of the named user |
| | 74 | (for example, at login time, or when a remote shell is invoked). |
| | 75 | .Sh RETURN VALUES |
| | 76 | If a call to |
| | 77 | .Fn getlogin |
| | 78 | succeeds, it returns a pointer to a null-terminated string in a static buffer. |
| | 79 | If the name has not been set, it returns |
| | 80 | .Dv NULL . |
| | 81 | If a call to |
| | 82 | .Fn setlogin |
| | 83 | succeeds, a value of 0 is returned. If |
| | 84 | .Fn setlogin |
| | 85 | fails, a value of -1 is returned and an error code is |
| | 86 | placed in the global location |
| | 87 | .Va errno . |
| | 88 | .Sh ERRORS |
| | 89 | The following errors may be returned by these calls: |
| | 90 | .Bl -tag -width Er |
| | 91 | .It Bq Er EFAULT |
| | 92 | The |
| | 93 | .Fa name |
| | 94 | parameter gave an |
| | 95 | invalid address. |
| | 96 | .It Bq Er EINVAL |
| | 97 | The |
| | 98 | .Fa name |
| | 99 | parameter |
| | 100 | pointed to a string that was too long. |
| | 101 | Login names are limited to |
| | 102 | .Dv MAXLOGNAME |
| | 103 | (from |
| | 104 | .Ao Pa sys/param.h Ac ) |
| | 105 | characters, currently 12. |
| | 106 | .It Bq Er EPERM |
| | 107 | The caller tried to set the login name and was not the super-user. |
| | 108 | .El |
| | 109 | .Sh SEE ALSO |
| | 110 | .Xr setsid 2 |
| | 111 | .Sh BUGS |
| | 112 | Login names are limited in length by |
| | 113 | .Fn setlogin . |
| | 114 | However, lower limits are placed on login names elsewhere in the system |
| | 115 | .Pf ( Dv UT_NAMESIZE |
| | 116 | in |
| | 117 | .Ao Pa utmp.h Ac ) . |
| | 118 | .Pp |
| | 119 | In earlier versions of the system, |
| | 120 | .Fn getlogin |
| | 121 | failed unless the process was associated with a login terminal. |
| | 122 | The current implementation (using |
| | 123 | .Fn setlogin ) |
| | 124 | allows getlogin to succeed even when the process has no controlling terminal. |
| | 125 | In earlier versions of the system, the value returned by |
| | 126 | .Fn getlogin |
| | 127 | could not be trusted without checking the user ID. |
| | 128 | Portable programs should probably still make this check. |
| | 129 | .Sh HISTORY |
| | 130 | The |
| | 131 | .Fn getlogin |
| | 132 | function first appeared in 4.4BSD. |
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