getspent(3C) COMPATIBILITY FUNCTIONS getspent(3C)
NAME
getspent, getspnam, setspent, endspent, fgetspent, lckpwdf,
ulckpwdf - manipulate shadow password file entry
SYNOPSIS
#include <shadow.h>
struct spwd *getspent (void);
struct spwd *getspnam (const char *name);
int lckpwdf (void);
int ulckpwdf (void);
void setspent (void);
void endspent (void);
struct spwd *fgetspent (FILE *fp);
DESCRIPTION
The getspent and getspnam routines each return a pointer to
an object with the following structure containing the
broken-out fields of a line in the /etc/shadow file. Each
line in the file contains a ``shadow password'' structure,
declared in the shadow.h header file:
struct spwd{
char *sp_namp;
char *sp_pwdp;
long sp_lstchg;
long sp_min;
long sp_max;
long sp_warn;
long sp_inact;
long sp_expire;
unsigned long sp_flag;
};
The getspent routine when first called returns a pointer to
the first spwd structure in the file; thereafter, it returns
a pointer to the next spwd structure in the file; so succes-
sive calls can be used to search the entire file. The
getspnam routine searches from the beginning of the file
until a login name matching name is found, and returns a
pointer to the particular structure in which it was found.
The getspent and getspnam routines populate the sp_min,
sp_max, sp_lstchg, sp_warn, sp_inact, sp_expire, or sp_flag
field with -1 if the corresponding field in /etc/shadow is
empty. If an end-of-file or an error is encountered on read-
ing, or there is a format error in the file, these functions
Last change: 1
getspent(3C) COMPATIBILITY FUNCTIONS getspent(3C)
return a null pointer and set errno to EINVAL.
/etc/.pwd.lock is the lock file. It is used to coordinate
modification access to the password files /etc/passwd and
/etc/shadow. lckpwdf and ulckpwdf are routines that are
used to gain modification access to the password files,
through the lock file. A process first uses lckpwdf to lock
the lock file, thereby gaining exclusive rights to modify
the /etc/passwd or /etc/shadow password file. Upon complet-
ing modifications, a process should release the lock on the
lock file via ulckpwdf. This mechanism prevents simultane-
ous modification of the password files.
lckpwdf attempts to lock the file /etc/.pwd.lock within 15
seconds. If unsuccessful, e.g., /etc/.pwd.lock is already
locked, it returns -1. If successful, a return code other
than -1 is returned.
ulckpwdf attempts to unlock the file /etc/.pwd.lock. If
unsuccessful, e.g., /etc/.pwd.lock is already unlocked, it
returns -1. If successful, it returns 0.
A call to the setspent routine has the effect of rewinding
the shadow password file to allow repeated searches. The
endspent routine may be called to close the shadow password
file when processing is complete.
The fgetspent routine returns a pointer to the next spwd
structure in the stream fp, which matches the format of
/etc/shadow.
FILES
/etc/shadow
/etc/passwd
/etc/.pwd.lock
SEE ALSO
getpwent(3C), putpwent(3C), putspent(3C).
DIAGNOSTICS
getspent, getspnam, lckpwdf, ulckpwdf, and fgetspent return
a null pointer on EOF or error.
NOTES
This routine is for internal use only; compatibility is not
guaranteed. All information is contained in a static area,
so it must be copied if it is to be saved.
Last change: 2