getpwuid

GETPWNAM(3)		  Linux Programmer’s Manual		  GETPWNAM(3)



NAME
       getpwnam, getpwnam_r, getpwuid, getpwuid_r - get password file entry

SYNOPSIS
       #include <sys/types.h>
       #include <pwd.h>

       struct passwd *getpwnam(const char *name);

       struct passwd *getpwuid(uid_t uid);

       int getpwnam_r(const char *name, struct passwd *pwbuf,
	       char *buf, size_t buflen, struct passwd **pwbufp);

       int getpwuid_r(uid_t uid, struct passwd *pwbuf,
	       char *buf, size_t buflen, struct passwd **pwbufp);

DESCRIPTION
       The  getpwnam()	function  returns a pointer to a structure containing
       the broken out fields of a line from /etc/passwd for  the  entry	 that
       matches the user name name.

       The  getpwuid()	function  returns a pointer to a structure containing
       the broken out fields of a line from /etc/passwd for  the  entry	 that
       matches the user uid uid.

       The getpwnam_r() and getpwuid_r() functions find the same information,
       but store the retrieved passwd structure in the space  pointed  to  by
       pwbuf.	This passwd 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 *pwbufp.

       The passwd structure is defined in <pwd.h> as follows:

	      struct passwd {
		    char    *pw_name;	   /* user name */
		    char    *pw_passwd;	   /* user password */
		    uid_t   pw_uid;	   /* user id */
		    gid_t   pw_gid;	   /* group id */
		    char    *pw_gecos;	   /* real name */
		    char    *pw_dir;	   /* home directory */
		    char    *pw_shell;	   /* shell program */
	      };

       The maximum needed size for buf can be found using sysconf(3) with the
       _SC_GETPW_R_SIZE_MAX parameter.

RETURN VALUE
       The getpwnam() and getpwuid() functions return a pointer to the passwd
       structure, or NULL if the matching entry is  not	 found	or  an	error
       occurs.	If  an error occurs, errno is set appropriately. If one wants
       to check errno after the call, it should be set	to  zero  before  the
       call.

       The  return  value may point to static area, and may be overwritten by
       subsequent calls to getpwent(), getpwnam(), or getpwuid().

       The  getpwnam_r() and getpwuid_r() functions return zero	 on  success.
       In case of error, an error value is returned.

ERRORS
       0 or ENOENT or ESRCH or EBADF or EPERM or ...
	      The given name or uid was not found.

       ENOMEM Insufficient memory to allocate passwd structure.

       EIO    I/O error.

       EINTR  A signal was caught.

       EMFILE The  maximum number (OPEN_MAX) of files was open already in the
	      calling process.

       ENFILE The maximum number of files was open already in the system.

       ERANGE Insufficient buffer space supplied.

FILES
       /etc/passwd
	      password database file

CONFORMING TO
       SVID 3, BSD 4.3, POSIX 1003.1-2003

NOTES
       The formulation	given  above  under  "RETURN  VALUE"  is  from	POSIX
       1003.1-2001.   It  does	not call "not found" an error, hence does not
       specify what value errno might have in this situation. But that	makes
       it  impossible  to recognize errors. One might argue that according to
       POSIX errno should be left unchanged if an entry is not found. Experi-
       ments on various Unix-like systems shows that lots of different values
       occur in this situation: 0, ENOENT, EBADF, ESRCH,  EWOULDBLOCK,	EPERM
       and probably others.

SEE ALSO
       fgetpwent(3),   getgrnam(3),  getpwent(3),  setpwent(3),	 endpwent(3),
       getpw(3), putpwent(3), passwd(5)



GNU				  1996-05-27			  GETPWNAM(3)