SHADOW(3)                                                                               SHADOW(3)



NAME
       shadow - encrypted password file routines

SYNTAX
       #include 

       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
       shadow  manipulates  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 warned of pending password  expi-
       ration.
       sp_inact - days after password expires that account is considered inactive 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  sgetspent  each return a pointer to a struct spwd.
       getspent returns the next entry from the file, and fgetspent returns the next  entry  from
       the given stream, which is assumed to be a file of the proper format.  sgetspent returns a
       pointer to a struct spwd using the provided string as input.  getspnam searches  from  the
       current position in the file for an 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  to  insure  exclusive  access  to  the
       /etc/shadow  file.  lckpwdf attempts to acquire a lock using pw_lock for up to 15 seconds.
       It continues by attempting to acquire a second lock using spw_lock for  the  remainder  of
       the  initial  15 seconds.  Should either attempt fail after a total of 15 seconds, lckpwdf
       returns -1.  When both locks are acquired 0 is returned.

DIAGNOSTICS
       Routines return NULL if no more entries are available or if an error  occurs  during  pro-
       cessing.   Routines  which  have  int  as the return value return 0 for success and -1 for
       failure.

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

FILES
       /etc/shadow - encrypted user passwords

SEE ALSO
       getpwent(3), shadow(5)

AUTHOR
       Julianne Frances Haugh ()



                                                                                        SHADOW(3)