ChorusOS man pages section 3STDC: Standard C Library Functions

getpwent(3STDC)

NAME

getpwent, getpwnam, getpwuid, setpassent, setpwent, endpwent- password database operations

SYNOPSIS

$(OS_DIR)/lib/libc.a
#include <sys/types.h>
#include <pwd.h>

login

uid

stayopen

API RESTRICTIONS

The function or functions documented here may not be used safely in all application contexts with all APIs provided in the ChorusOS 5.0 product.

See API(5FEA) for details.

DESCRIPTION

These functions operate on the password database file which is described in passwd(4CC) . Each entry in the database is defined by the structure passwd found in the include file <pwd.h> as follows:

struct passwd {
    char    *pw_name;  /* user name */
    char    *pw_passwd;/* encrypted password */
    uid_t   pw_uid;    /* user uid */
    gid_t   pw_gid;    /* user gid */
    time_t  pw_change; /* password change time */
    char    *pw_class; /* user access class */
    char    *pw_gecos; /* general login information */
    char    *pw_dir;   /* home directory */
    char    *pw_shell; /* default shell */
    time_t  pw_expire; /* account expiration */
    intpw_fields; /* internal: fields filled in */
 };

The functions getpwnam() and getpwuid() search the password database for the given login name or user uid , respectively, always returning the first one encountered.

The getpwent() function sequentially reads the password database and is intended for programs that wish to process the complete list of users.

The setpassent() function accomplishes two purposes. First, it causes getpwent() to rewind to the beginning of the database. Additionally, if stayopen is non-zero, file descriptors are left open, significantly speeding up subsequent accesses for all of the routines. (This latter functionality is unnecessary for getpwent() as it doesn't close its file descriptors by default.)

It is dangerous for long-running programs to keep the file descriptors open as the database will become out of date if it is updated while the program is running.

The setpwent() function is identical to setpassent() with an argument of zero.

The endpwent() function closes any open files.

These routines have been written to shadow the password file. for example, allow only certain programs to have access to the encrypted password. If the process which calls them has an effective uid of 0, the encrypted password will be returned, otherwise, the password field of the returned structure will point to the string `*'.

RETURN VALUES

The functions getpwent() , getpwnam() , and getpwuid() , return a valid pointer to a password structure on success and a null pointer if end-of- file is reached or an error occurs. The setpassent() function returns 0 on failure and 1 on success. The endpwent() and setpwent() functions have no return value.

FILES

/etc/pwd.db: The insecure password database file
/etc/spwd.db: The secure password database file
/etc/master.passwd: The current password file
/etc/passwd: A Version 7 format password file

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPE	ATTRIBUTE VALUE
Interface Stability	Evolving

BUGS

The functions getpwent() , getpwnam() , and getpwuid() leave their results in an internal static object and return a pointer to that object. Subsequent calls to the same function will modify the same object.

ChorusOS 5.0 Last Revised December 2001