shadow

SHADOW(3)                                                            SHADOW(3)



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
       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 expiration.
       sp_inact - days after password expires that account is considered inac-
       tive 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 processing.  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 (jockgrrl@ix.netcom.com)



                                                                     SHADOW(3)