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'\" t
.\" Title: shadow
.\" Author: Julianne Frances Haugh
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\" Date: 01/23/2020
.\" Manual: Library Calls
.\" Source: shadow-utils 4.8.1
.\" Language: English
.\"
.TH "SHADOW" "3" "01/23/2020" "shadow\-utils 4\&.8\&.1" "Library Calls"
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
shadow, getspnam \- encrypted password file routines
.SH "SYNTAX"
.PP
\fI#include <shadow\&.h>\fR
.PP
\fIstruct spwd *getspent();\fR
.PP
\fIstruct spwd *getspnam(char\fR
\fI*name\fR\fI);\fR
.PP
\fIvoid setspent();\fR
.PP
\fIvoid endspent();\fR
.PP
\fIstruct spwd *fgetspent(FILE\fR
\fI*fp\fR\fI);\fR
.PP
\fIstruct spwd *sgetspent(char\fR
\fI*cp\fR\fI);\fR
.PP
\fIint putspent(struct spwd\fR
\fI*p,\fR
\fIFILE\fR
\fI*fp\fR\fI);\fR
.PP
\fIint lckpwdf();\fR
.PP
\fIint ulckpwdf();\fR
.SH "DESCRIPTION"
.PP
\fIshadow\fR
manipulates the contents of the shadow password file,
/etc/shadow\&. The structure in the
\fI#include\fR
file is:
.sp
.if n \{\
.RS 4
.\}
.nf
struct spwd {
char *sp_namp; /* user login name */
char *sp_pwdp; /* encrypted password */
long int sp_lstchg; /* last password change */
long int sp_min; /* days until change allowed\&. */
long int sp_max; /* days before change required */
long int sp_warn; /* days warning for expiration */
long int sp_inact; /* days before account inactive */
long int sp_expire; /* date when account expires */
unsigned long int sp_flag; /* reserved for future use */
}
.fi
.if n \{\
.RE
.\}
.PP
The meanings of each field are:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
sp_namp \- pointer to null\-terminated user name
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
sp_pwdp \- pointer to null\-terminated password
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
sp_lstchg \- days since Jan 1, 1970 password was last changed
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
sp_min \- days before which password may not be changed
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
sp_max \- days after which password must be changed
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
sp_warn \- days before password is to expire that user is warned of pending password expiration
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
sp_inact \- days after password expires that account is considered inactive and disabled
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
sp_expire \- days since Jan 1, 1970 when account will be disabled
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
sp_flag \- reserved for future use
.RE
.SH "DESCRIPTION"
.PP
\fIgetspent\fR,
\fIgetspname\fR,
\fIfgetspent\fR, and
\fIsgetspent\fR
each return a pointer to a
\fIstruct spwd\fR\&.
\fIgetspent\fR
returns the next entry from the file, and
\fIfgetspent\fR
returns the next entry from the given stream, which is assumed to be a file of the proper format\&.
\fIsgetspent\fR
returns a pointer to a
\fIstruct spwd\fR
using the provided string as input\&.
\fIgetspnam\fR
searches from the current position in the file for an entry matching
\fIname\fR\&.
.PP
\fIsetspent\fR
and
\fIendspent\fR
may be used to begin and end, respectively, access to the shadow password file\&.
.PP
The
\fIlckpwdf\fR
and
\fIulckpwdf\fR
routines should be used to insure exclusive access to the
/etc/shadow
file\&.
\fIlckpwdf\fR
attempts to acquire a lock using
\fIpw_lock\fR
for up to 15 seconds\&. It continues by attempting to acquire a second lock using
\fIspw_lock\fR
for the remainder of the initial 15 seconds\&. Should either attempt fail after a total of 15 seconds,
\fIlckpwdf\fR
returns \-1\&. When both locks are acquired 0 is returned\&.
.SH "DIAGNOSTICS"
.PP
Routines return NULL if no more entries are available or if an error occurs during processing\&. Routines which have
\fIint\fR
as the return value return 0 for success and \-1 for failure\&.
.SH "CAVEATS"
.PP
These routines may only be used by the superuser as access to the shadow password file is restricted\&.
.SH "FILES"
.PP
/etc/shadow
.RS 4
Secure user account information\&.
.RE
.SH "SEE ALSO"
.PP
\fBgetpwent\fR(3),
\fBshadow\fR(5)\&.
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