MAN page from RedHat 5.X shadow-utils-980403-3.i386.rpm

SHADOW

Section: C Library Functions (3)
Index

NAME

shadow - encrypted password file routines

SYNTAX

#include <shadow.h>

struct spwd *getspent();

struct spwd *getspnam(char*name);

void setspent();

void endspent();

struct spwd *fgetspent(FILE*fp);

struct spwd *sgetspent(char*cp);

int putspent(struct spwd*p,FILE*fp);

int lckpwdf();

int ulckpwdf();

DESCRIPTION

shadowmanipulates the contents of the shadow password file,/etc/shadow.The structure in the #include file is

struct spwd {
       char    *sp_namp; /* user login name */

       char    *sp_pwdp; /* encrypted password */

       long    sp_lstchg; /* last password change */

       int     sp_min; /* days until change allowed. */

       int     sp_max; /* days before change required */

       int     sp_warn; /* days warning for expiration */

       int     sp_inact; /* days before account inactive */

       int     sp_expire; /* date when account expires */

       int     sp_flag; /* reserved for future use */

}

The meanings of each field are

sp_namp - pointer to null-terminated user name.
sp_pwdp - pointer to null-terminated password.
sp_lstchg - days since Jan 1, 1970 password was last changed.
sp_min - days before which password may not be changed.
sp_max - days after which password must be changed.
sp_warn - days before password is to expire that user is warnedof pending password expiration.
sp_inact - days after password expires that account is consideredinactive and disabled.
sp_expire - days since Jan 1, 1970 when account will be disabled.
sp_flag - reserved for future use.

DESCRIPTION

getspent, getspname, fgetspent, and sgetspenteach return a pointer to a struct spwd.getspent returns thenext entry from the file, and fgetspent returns the nextentry from the given stream, which is assumed to be a file ofthe proper format.sgetspent returns a pointer to a struct spwd using theprovided string as input.getspnam searches from the current position in the file foran entry matching name.

setspent and endspent may be used to begin and end,respectively, access to the shadow password file.

The lckpwdf and ulckpwdf routines should be used toinsure exclusive access to the /etc/shadow file.lckpwdf attempts to acquire a lock using pw_lock forup to 15 seconds.It continues by attempting to acquire a second lock using spw_lockfor the remainder of the initial 15 seconds.Should either attempt fail after a total of 15 seconds, lckpwdfreturns -1.When both locks are acquired 0 is returned.

DIAGNOSTICS

Routines return NULL if no more entries are available or if anerror occurs during processing.Routines which have int as the return value return 0 forsuccess and -1 for failure.

CAVEATS

These routines may only be used by the super user as access tothe shadow password file is restricted.

FILES

/etc/shadow - encrypted user passwords

AUTHOR

Julianne Frances Haugh (jfhAATTtab.com)

This document was created byman2html,using the manual pages.

SHADOW

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