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GETSPNAM(3)                Linux Programmer's Manual               GETSPNAM(3)



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

SYNOPSIS
       /* General shadow password file API */
       #include <&lt;shadow.h>&gt;

       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 */
       #include <&lt;shadow.h>&gt;

       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

DESCRIPTION
       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
       root.

       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
       spwd.

       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.

   Structure
       The shadow password structure is defined in &lt;shadow.h&gt; 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 */
           };

RETURN VALUE
       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.

ERRORS
       ERANGE Supplied buffer is too small.

FILES
       /etc/shadow
              local shadow password database file

       /etc/.pwd.lock
              lock file

       The include file &lt;paths.h&gt; defines the  constant  _PATH_SHADOW  to  the
       pathname of the shadow password file.

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

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

COLOPHON
       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)