term% cat index.txt GETPWENT(3) Library Functions Manual GETPWENT(3)
NAME
getpwent, getpwuid, getpwnam, setpwent, endpwent - get password file
entry
SYNOPSIS
#include <pwd.h>
struct passwd *getpwent();
struct passwd *getpwuid(uid) int uid;
struct passwd *getpwnam(name) char *name;
int setpwent();
int endpwent();
DESCRIPTION
Getpwent, getpwuid and getpwnam each return a pointer to an object with
the following structure containing the broken-out fields of a line in
the password file.
/* Copyright (C) 1991-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/*
* POSIX Standard: 9.2.2 User Database Access <pwd.h>
*/
#ifndef _PWD_H
#define _PWD_H 1
#include <features.h>
__BEGIN_DECLS
#include <bits/types.h>
#define __need_size_t
#include <stddef.h>
#if defined __USE_XOPEN || defined __USE_XOPEN2K
/* The Single Unix specification says that some more types are
available here. */
# ifndef __gid_t_defined
typedef __gid_t gid_t;
# define __gid_t_defined
# endif
# ifndef __uid_t_defined
typedef __uid_t uid_t;
# define __uid_t_defined
# endif
#endif
/* A record in the user database. */
struct passwd
{
char *pw_name; /* Username. */
char *pw_passwd; /* Hashed passphrase, if shadow database
not in use (see shadow.h). */
__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. */
};
#ifdef __USE_MISC
# include <bits/types/FILE.h>
#endif
#if defined __USE_MISC || defined __USE_XOPEN_EXTENDED
/* Rewind the user database stream.
This function is a possible cancellation point and therefore not
marked with __THROW. */
extern void setpwent (void);
/* Close the user database stream.
This function is a possible cancellation point and therefore not
marked with __THROW. */
extern void endpwent (void);
/* Read an entry from the user database stream, opening it if necessary.
This function is a possible cancellation point and therefore not
marked with __THROW. */
extern struct passwd *getpwent (void);
#endif
#ifdef __USE_MISC
/* Read a user database entry from STREAM.
This function is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
extern struct passwd *fgetpwent (FILE *__stream) __nonnull ((1));
/* Write a given user database entry onto the given stream.
This function is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
extern int putpwent (const struct passwd *__restrict __p,
FILE *__restrict __f);
#endif
/* Retrieve the user database entry for the given user ID.
This function is a possible cancellation point and therefore not
marked with __THROW. */
extern struct passwd *getpwuid (__uid_t __uid);
/* Retrieve the user database entry for the given username.
This function is a possible cancellation point and therefore not
marked with __THROW. */
extern struct passwd *getpwnam (const char *__name) __nonnull ((1));
#ifdef __USE_POSIX
# ifdef __USE_MISC
/* Reasonable value for the buffer sized used in the reentrant
functions below. But better use `sysconf'. */
# define NSS_BUFLEN_PASSWD 1024
# endif
/* Reentrant versions of some of the functions above.
PLEASE NOTE: the `getpwent_r' function is not (yet) standardized.
The interface may change in later versions of this library. But
the interface is designed following the principals used for the
other reentrant functions so the chances are good this is what the
POSIX people would choose. */
# ifdef __USE_MISC
/* This function is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
extern int getpwent_r (struct passwd *__restrict __resultbuf,
char *__restrict __buffer, size_t __buflen,
struct passwd **__restrict __result)
__nonnull ((1, 2, 4))
__attr_access ((__write_only__, 2, 3));
# endif
extern int getpwuid_r (__uid_t __uid,
struct passwd *__restrict __resultbuf,
char *__restrict __buffer, size_t __buflen,
struct passwd **__restrict __result)
__nonnull ((2, 3, 5))
__attr_access ((__write_only__, 3, 4));
extern int getpwnam_r (const char *__restrict __name,
struct passwd *__restrict __resultbuf,
char *__restrict __buffer, size_t __buflen,
struct passwd **__restrict __result)
__nonnull ((1, 2, 3, 5))
__attr_access ((__write_only__, 3, 4));
# ifdef __USE_MISC
/* Read a user database entry from STREAM. This function is not
standardized and probably never will.
This function is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
extern int fgetpwent_r (FILE *__restrict __stream,
struct passwd *__restrict __resultbuf,
char *__restrict __buffer, size_t __buflen,
struct passwd **__restrict __result)
__nonnull ((1, 2, 3, 5))
__attr_access ((__write_only__, 3, 4));
# endif
#endif /* POSIX or reentrant */
#ifdef __USE_GNU
/* Write a traditional /etc/passwd line, based on the user database
entry for the given UID, to BUFFER; space for BUFFER must be
allocated by the caller.
This function is not part of POSIX and therefore no official
cancellation point. But due to similarity with an POSIX interface
or due to the implementation it is a cancellation point and
therefore not marked with __THROW. */
extern int getpw (__uid_t __uid, char *__buffer);
#endif
__END_DECLS
#endif /* pwd.h */
The fields pw_quota and pw_comment are unused; the others have meanings
described in passwd(5).
Getpwent reads the next line (opening the file if necessary); setpwent
rewinds the file; endpwent closes it.
Getpwuid and getpwnam search from the beginning until a matching uid or
name is found (or until EOF is encountered).
FILES
/etc/passwd
SEE ALSO
getlogin(3), getgrent(3), passwd(5)
DIAGNOSTICS
Null pointer (0) returned on EOF or error.
BUGS
All information is contained in a static area so it must be copied if
it is to be saved.
GETPWENT(3)