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GETSPNAM(3)		   Linux Programmers Manual		  GETSPNAM(3)

       getspnam,  getspnam_r,  getspent, getspent_r, setspent, endspent, fget
       spent, fgetspent_r, sgetspent, sgetspent_r, putspent, lckpwdf, ulckpwdf
       - get shadow password file entry

       /* General shadow password file API */

       struct spwd *getspnam(const char *name);

       struct spwd *getspent(void);

       void setspent(void);

       void endspent(void);

       struct spwd *fgetspent(FILE *fp);

       struct spwd *sgetspent(const char *s);

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

       int lckpwdf(void);

       int ulckpwdf(void);

       /* GNU extension */

       int getspent_r(struct spwd *spbuf,
	       char *buf, size_t buflen, struct spwd **spbufp);

       int getspnam_r(const char *name, struct spwd *spbuf,
	       char *buf, size_t buflen, struct spwd **spbufp);

       int fgetspent_r(FILE *fp, struct spwd *spbuf,
	       char *buf, size_t buflen, struct spwd **spbufp);

       int sgetspent_r(const char *s, struct spwd *spbuf,
	       char *buf, size_t buflen, struct spwd **spbufp);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getspent_r(), getspnam_r(), fgetspent_r(), sgetspent_r(): _BSD_SOURCE
       || _SVID_SOURCE

       Long ago it was considered safe to have encrypted passwords openly vis
       ible  in  the  password file.  When computers got faster and people got
       more security-conscious,  this  was  no	longer	acceptable.   Julianne
       Frances	Haugh  implemented  the  shadow  password suite that keeps the
       encrypted passwords in the shadow password database  (e.g.,  the  local
       shadow  password  file  /etc/shadow,  NIS,  and LDAP), readable only by

       The functions described below resemble those for the traditional  pass
       word database (e.g., see getpwnam(3) and getpwent(3)).

       The getspnam() function returns a pointer to a structure containing the
       broken-out fields of the record in the shadow  password	database  that
       matches the username name.

       The  getspent()	function  returns  a  pointer to the next entry in the
       shadow password database.  The position in the input stream is initial
       ized by setspent().  When done reading, the program may call endspent()
       so that resources can be deallocated.

       The fgetspent() function is similar to getspent() but uses the supplied
       stream instead of the one implicitly opened by setspent().

       The  sgetspent()  function  parses  the supplied string s into a struct

       The putspent() function writes the contents of the supplied struct spwd
       *p  as a text line in the shadow password file format to the stream fp.
       String entries with value NULL and numerical entries with value -1  are
       written as an empty string.

       The lckpwdf() function is intended to protect against multiple simulta
       neous accesses of the shadow password database.	It tries to acquire  a
       lock,  and  returns  0  on success, or -1 on failure (lock not obtained
       within 15 seconds).  The ulckpwdf() function releases the  lock	again.
       Note  that  there  is no protection against direct access of the shadow
       password file.  Only programs that use lckpwdf() will notice the  lock.

       These were the functions that formed the original shadow API.  They are
       widely available.

   Reentrant versions
       Analogous to the reentrant functions for the password  database,  glibc
       also  has  reentrant  functions	for the shadow password database.  The
       getspnam_r() function is  like  getspnam()  but	stores	the  retrieved
       shadow  password  structure  in	the  space  pointed to by spbuf.  This
       shadow password structure  contains  pointers  to  strings,  and  these
       strings	are stored in the buffer buf of size buflen.  A pointer to the
       result (in case of success) or NULL (in case no entry was found	or  an
       error occurred) is stored in *spbufp.

       The  functions getspent_r(), fgetspent_r(), and sgetspent_r() are simi
       larly analogous to their non-reentrant counterparts.

       Some non-glibc systems also have functions with these names, often with
       different prototypes.

       The shadow password structure is defined in  as follows:

	   struct spwd {
	       char *sp_namp;	  /* Login name */
	       char *sp_pwdp;	  /* Encrypted password */
	       long  sp_lstchg;   /* Date of last change (measured
				     in days since 1 Jan 1970) */
	       long  sp_min;	  /* Min # of days between changes */
	       long  sp_max;	  /* Max # of days between changes */
	       long  sp_warn;	  /* # of days before password expires
				     to warn user to change it */
	       long  sp_inact;	  /* # of days after password expires
				     until account is disabled */
	       long  sp_expire;   /* Date when account expires (measured
				     in days since 1 Jan 1970) */
	       unsigned long sp_flag;  /* Reserved */

       The  functions that return a pointer return NULL if no more entries are
       available or if an error occurs during processing.  The functions which
       have int as the return value return 0 for success and -1 for failure.

       For  the  non-reentrant functions, the return value may point to static
       area, and may be overwritten by subsequent calls to these functions.

       The reentrant functions return zero on success.	In case of  error,  an
       error number is returned.

       ERANGE Supplied buffer is too small.

	      local shadow password database file

	      lock file

       The  include  file    defines the constant _PATH_SHADOW to the
       pathname of the shadow password file.

       The shadow password database and its associated API are	not  specified
       in POSIX.1-2001.  However, many other systems provide a similar API.

       getgrnam(3), getpwnam(3), getpwnam_r(3), shadow(5)

       This  page  is  part of release 3.05 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

GNU				  2008-07-09			   GETSPNAM(3)

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