139 lines
3.2 KiB
Groff
139 lines
3.2 KiB
Groff
.TH GETPWENT 3
|
|
.SH NAME
|
|
getpwent, getpwnam, getpwuid, setpwent, endpwent, setpwfile \- password file routines
|
|
.SH SYNOPSIS
|
|
.ft B
|
|
.nf
|
|
#include <pwd.h>
|
|
|
|
struct passwd *getpwent(void)
|
|
struct passwd *getpwnam(const char *\fIname\fP)
|
|
struct passwd *getpwuid(uid_t \fIuid\fP)
|
|
int setpwent(void)
|
|
void endpwent(void)
|
|
void setpwfile(const char *\fIfile\fP)
|
|
.fi
|
|
.ft P
|
|
.SH DESCRIPTION
|
|
These functions are used to obtain information from the password file. They
|
|
return this information in a
|
|
.B struct passwd
|
|
as defined by <pwd.h>:
|
|
.PP
|
|
.nf
|
|
.ta +4n +6n +15n
|
|
struct passwd {
|
|
char *pw_name; /* login name */
|
|
char *pw_passwd; /* encrypted password */
|
|
uid_t pw_uid; /* numeric user id */
|
|
gid_t pw_gid; /* numeric group id */
|
|
char *pw_gecos; /* user full name and other info */
|
|
char *pw_dir; /* user's home directory */
|
|
char *pw_shell; /* name of the user's shell */
|
|
};
|
|
.fi
|
|
.PP
|
|
.B Getpwent()
|
|
reads the password file entry by entry.
|
|
.B Getpwnam()
|
|
scans the entire password file for the user with the given
|
|
.IR name .
|
|
.B Getpwuid()
|
|
looks for the first user with the given
|
|
.IR uid .
|
|
The
|
|
.B setpwent()
|
|
and
|
|
.B endpwent()
|
|
functions are used to open and later close the password file. With
|
|
.B setpwfile()
|
|
one can specify the file to read other than the normal password file. This
|
|
only sets the name, the next
|
|
.B setpwent()
|
|
call will open the file. Do not touch the file name while it is active.
|
|
Use
|
|
.B setpwfile(NULL)
|
|
to revert back to the normal password file.
|
|
.PP
|
|
The usual way to scan the password file is (error checking omitted):
|
|
.PP
|
|
.RS
|
|
.nf
|
|
.DT
|
|
setpwent();
|
|
while ((pw = getpwent()) != NULL)
|
|
if (appropriate_test(pw)) break;
|
|
endpwent();
|
|
.fi
|
|
.RE
|
|
.PP
|
|
The
|
|
.B pw
|
|
variable contains the entry that is wanted if non-NULL. The
|
|
.B getpwnam()
|
|
and
|
|
.B getpwuid()
|
|
functions are implemented as in this example, with error checking of course.
|
|
.PP
|
|
.B Getpwent()
|
|
calls
|
|
.B setpwent()
|
|
if this has not yet been done.
|
|
.B Setpwent()
|
|
first calls
|
|
.B endpwent()
|
|
if the password file is still open. (Other implementations may simply
|
|
rewind the file.)
|
|
.SH FILES
|
|
.TP 15
|
|
.B /etc/passwd
|
|
The password file database.
|
|
.SH "SEE ALSO"
|
|
.BR cuserid (3),
|
|
.BR getlogin (3),
|
|
.BR getgrent (3),
|
|
.BR passwd (5).
|
|
.SH DIAGNOSTICS
|
|
.B Setpwent()
|
|
has the same return value and error codes as the
|
|
.BR open (2)
|
|
call it uses to open the password file. The
|
|
.BI get xxx ()
|
|
functions return NULL on end of file, entry not found, or error. You can
|
|
set
|
|
.B errno
|
|
to zero before the call and check it after.
|
|
.SH NOTES
|
|
All
|
|
.BI get xxx ()
|
|
routines return a pointer to static storage that is overwritten in each call.
|
|
.PP
|
|
Only
|
|
.B getpwnam()
|
|
and
|
|
.B getpwuid()
|
|
are defined by \s-2POSIX\s+2. The
|
|
.B _MINIX_SOURCE
|
|
macro must be defined before including <pwd.h> to make the other functions
|
|
visible. The
|
|
.B pw_passwd
|
|
and
|
|
.B pw_gecos
|
|
fields are also not defined by \s-2POSIX\s+2, but are always visible.
|
|
Portable code cannot reliably detect errors by setting
|
|
.B errno
|
|
to zero. Under MINIX 3 it is better to make a
|
|
.B getpwent()
|
|
scan if you need to look up several user-id's or names, but portable code
|
|
had better use several
|
|
.B getpwuid()
|
|
or
|
|
.B getpwnam()
|
|
calls. The
|
|
.B getpwent()
|
|
is usually available on other systems, but may be very expensive.
|
|
.SH AUTHOR
|
|
Kees J. Bot (kjb@cs.vu.nl)
|
|
|
|
.\"
|
|
.\" $PchId: getpwent.3,v 1.2 1996/04/11 06:37:43 philip Exp $
|