projects / unix-history / blame
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|---|---|---|
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1 | .\" Copyright (c) 1989 The Regents of the University of California. |
| 2 | .\" All rights reserved. | |
| 3 | .\" | |
| d79c3924 | 4 | .\" %sccs.include.redist.man% |
| 1cde5d8e | 5 | .\" |
| 554c3e4b | 6 | .\" @(#)getlogin.2 6.1 (Berkeley) %G% |
| 1cde5d8e | 7 | .\" |
| d79c3924 | 8 | .TH GETLOGIN 2 "" |
| 1cde5d8e KF |
9 | .UC 5 |
| 10 | .SH NAME | |
| d79c3924 | 11 | getlogin, setlogin \- get/set login name |
| 1cde5d8e KF |
12 | .SH SYNOPSIS |
| 13 | .nf | |
| 14 | .ft B | |
| d79c3924 | 15 | char *getlogin() |
| 1cde5d8e KF |
16 | .PP |
| 17 | .ft B | |
| d79c3924 | 18 | setlogin(name) |
| 1cde5d8e | 19 | char *name; |
| 1cde5d8e KF |
20 | .fi |
| 21 | .SH DESCRIPTION | |
| d79c3924 MK |
22 | The |
| 23 | .I getlogin | |
| 24 | routine | |
| 25 | returns the login name of the user associated with the current session, | |
| 26 | as previously set by | |
| 27 | .IR setlogin . | |
| 28 | The name is normally associated with a login shell | |
| 29 | at the time a session is created, | |
| 30 | and is inherited by all processes descended from the login shell. | |
| 31 | (This is true even if some of those processes assume another user ID, | |
| 32 | for example when | |
| 33 | .IR su (1) | |
| 34 | is used.) | |
| 1cde5d8e | 35 | .PP |
| d79c3924 MK |
36 | .I Setlogin |
| 37 | sets the login name of the user associated with the current session to | |
| 38 | .IR name . | |
| 39 | This call is restricted to the super-user, and | |
| 40 | is normally used only when a new session is being created on behalf | |
| 41 | of the named user | |
| 42 | (for example, at login time, or when a remote shell is invoked). | |
| 1cde5d8e | 43 | .SH "RETURN VALUE |
| d79c3924 MK |
44 | If a call to |
| 45 | .I getlogin | |
| 46 | succeeds, it returns a pointer to a null-terminated string in a static buffer. | |
| 47 | If the name has not been set, it returns NULL. | |
| 48 | If a call to | |
| 49 | .I setlogin | |
| 50 | succeeds, a value of 0 is returned. If | |
| 51 | .I setlogin | |
| 1cde5d8e KF |
52 | fails, then a value of \-1 is returned and an error code is |
| 53 | placed in the global location \fIerrno\fP. | |
| 54 | .SH "ERRORS | |
| 55 | The following errors may be returned by these calls: | |
| 56 | .TP 15 | |
| 57 | [EFAULT] | |
| d79c3924 | 58 | The \fIname\fP parameter gave an |
| 1cde5d8e KF |
59 | invalid address. |
| 60 | .TP 15 | |
| d79c3924 MK |
61 | [EINVAL] |
| 62 | The \fIname\fP parameter | |
| 63 | pointed to a string that was too long. | |
| 64 | Login names are limited to MAXLOGNAME (from | |
| 65 | .IR <sys/param.h> ) | |
| 66 | characters, currently 12. | |
| 67 | .TP 15 | |
| 1cde5d8e | 68 | [EPERM] |
| d79c3924 | 69 | The caller tried to set the login name and was not the super-user. |
| 1cde5d8e | 70 | .SH SEE ALSO |
| d79c3924 | 71 | setsid(2) |
| 1cde5d8e | 72 | .SH BUGS |
| d79c3924 MK |
73 | Login names are limited in length by |
| 74 | .IR setlogin . | |
| 75 | However, lower limits are placed on login names elsewhere in the system | |
| 76 | (UT_NAMESIZE in | |
| 77 | .IR <utmp.h> ). | |
| 78 | .PP | |
| 79 | In earlier versions of the system, | |
| 80 | .I getlogin | |
| 81 | failed unless the process was associated with a login terminal. | |
| 82 | The current implementation (using | |
| 83 | .IR setlogin ) | |
| 84 | allows getlogin to succeed even when the process has no controlling terminal. | |
| 85 | In earlier versions of the system, the value returned by | |
| 86 | .I getlogin | |
| 87 | could not be trusted without checking the user ID. | |
| 88 | Portable programs should probably still make this check. |