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931b8415 | 1 | .\" Copyright (c) 1989, 1991 The Regents of the University of California. |
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2 | .\" All rights reserved. |
3 | .\" | |
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4 | .\" Redistribution and use in source and binary forms, with or without |
5 | .\" modification, are permitted provided that the following conditions | |
6 | .\" are met: | |
7 | .\" 1. Redistributions of source code must retain the above copyright | |
8 | .\" notice, this list of conditions and the following disclaimer. | |
9 | .\" 2. Redistributions in binary form must reproduce the above copyright | |
10 | .\" notice, this list of conditions and the following disclaimer in the | |
11 | .\" documentation and/or other materials provided with the distribution. | |
12 | .\" 3. All advertising materials mentioning features or use of this software | |
13 | .\" must display the following acknowledgement: | |
14 | .\" This product includes software developed by the University of | |
15 | .\" California, Berkeley and its contributors. | |
16 | .\" 4. Neither the name of the University nor the names of its contributors | |
17 | .\" may be used to endorse or promote products derived from this software | |
18 | .\" without specific prior written permission. | |
1cde5d8e | 19 | .\" |
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20 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
21 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
22 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
23 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
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1cde5d8e | 31 | .\" |
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32 | .\" @(#)getlogin.2 6.3 (Berkeley) 7/23/91 |
33 | .\" | |
34 | .Dd July 23, 1991 | |
931b8415 CL |
35 | .Dt GETLOGIN 2 |
36 | .Os BSD 4.2 | |
37 | .Sh NAME | |
38 | .Nm getlogin , | |
39 | .Nm setlogin | |
40 | .Nd get/set login name | |
41 | .Sh SYNOPSIS | |
42 | .Fd #include <unistd.h> | |
43 | .Ft char * | |
44 | .Fn getlogin void | |
45 | .Ft int | |
46 | .Fn setlogin "const char *name" | |
47 | .Sh DESCRIPTION | |
d79c3924 | 48 | The |
931b8415 | 49 | .Fn getlogin |
d79c3924 MK |
50 | routine |
51 | returns the login name of the user associated with the current session, | |
52 | as previously set by | |
931b8415 | 53 | .Fn setlogin . |
d79c3924 MK |
54 | The name is normally associated with a login shell |
55 | at the time a session is created, | |
56 | and is inherited by all processes descended from the login shell. | |
57 | (This is true even if some of those processes assume another user ID, | |
58 | for example when | |
931b8415 | 59 | .Xr su 1 |
d79c3924 | 60 | is used.) |
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61 | .Pp |
62 | .Fn Setlogin | |
d79c3924 | 63 | sets the login name of the user associated with the current session to |
931b8415 | 64 | .Fa name . |
d79c3924 MK |
65 | This call is restricted to the super-user, and |
66 | is normally used only when a new session is being created on behalf | |
67 | of the named user | |
68 | (for example, at login time, or when a remote shell is invoked). | |
931b8415 | 69 | .Sh RETURN VALUES |
d79c3924 | 70 | If a call to |
931b8415 | 71 | .Fn getlogin |
d79c3924 | 72 | succeeds, it returns a pointer to a null-terminated string in a static buffer. |
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73 | If the name has not been set, it returns |
74 | .Dv NULL . | |
d79c3924 | 75 | If a call to |
931b8415 | 76 | .Fn setlogin |
d79c3924 | 77 | succeeds, a value of 0 is returned. If |
931b8415 CL |
78 | .Fn setlogin |
79 | fails, a value of -1 is returned and an error code is | |
80 | placed in the global location | |
81 | .Va errno . | |
82 | .Sh ERRORS | |
1cde5d8e | 83 | The following errors may be returned by these calls: |
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84 | .Bl -tag -width Er |
85 | .It Bq Er EFAULT | |
86 | The | |
87 | .Fa name | |
88 | parameter gave an | |
1cde5d8e | 89 | invalid address. |
931b8415 CL |
90 | .It Bq Er EINVAL |
91 | The | |
92 | .Fa name | |
93 | parameter | |
d79c3924 | 94 | pointed to a string that was too long. |
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95 | Login names are limited to |
96 | .Dv MAXLOGNAME | |
97 | (from | |
98 | .Ao Pa sys/param.h Ac ) | |
d79c3924 | 99 | characters, currently 12. |
931b8415 | 100 | .It Bq Er EPERM |
d79c3924 | 101 | The caller tried to set the login name and was not the super-user. |
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102 | .El |
103 | .Sh SEE ALSO | |
104 | .Xr setsid 2 | |
105 | .Sh BUGS | |
d79c3924 | 106 | Login names are limited in length by |
931b8415 | 107 | .Fn setlogin . |
d79c3924 | 108 | However, lower limits are placed on login names elsewhere in the system |
931b8415 CL |
109 | .Pf ( Dv UT_NAMESIZE |
110 | in | |
111 | .Ao Pa utmp.h Ac ) . | |
112 | .Pp | |
d79c3924 | 113 | In earlier versions of the system, |
931b8415 | 114 | .Fn getlogin |
d79c3924 MK |
115 | failed unless the process was associated with a login terminal. |
116 | The current implementation (using | |
931b8415 | 117 | .Fn setlogin ) |
d79c3924 MK |
118 | allows getlogin to succeed even when the process has no controlling terminal. |
119 | In earlier versions of the system, the value returned by | |
931b8415 | 120 | .Fn getlogin |
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121 | could not be trusted without checking the user ID. |
122 | Portable programs should probably still make this check. | |
931b8415 CL |
123 | .Sh HISTORY |
124 | The | |
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125 | .Nm getlogin |
126 | function call is | |
127 | .Ud . |