NAME
pw_init, pw_edit,
pw_prompt, pw_copy,
pw_copyx, pw_scan,
pw_error —
utility functions for interactive
passwd file updates
LIBRARY
library “libutil”
SYNOPSIS
#include <pwd.h>
#include <util.h>
void
pw_init(void);
void
pw_edit(int
notsetuid, const char
*filename);
void
pw_prompt(void);
void
pw_copy(int
ffd, int tfd,
struct passwd *pw,
struct passwd
*old_pw);
int
pw_copyx(int
ffd, int tfd,
struct passwd *pw,
struct passwd *old_pw,
char *errbuf,
size_t errbufsz);
int
pw_scan(char
*bp, struct passwd
*pw, int
*flags);
void
pw_error(const
char *name, int
err, int eval);
DESCRIPTION
These functions are designed as conveniences for interactive programs which update the passwd file and do nothing else. They generally handle errors by printing out a message to the standard error stream and possibly aborting the process.The
pw_init()
function prepares for a passwd update by unlimiting all resource
constraints, disabling core dumps (thus preventing dumping the contents of
the passwd database into a world-readable file), and disabling most
signals.
The
pw_edit()
function runs an editor (named by the environment variable EDITOR, or
/usr/bin/vi if EDITOR is not set) on the file
filename (or /etc/ptmp if
filename is NULL). If
notsetuid is nonzero,
pw_edit() will set the effective user and group ID
to the real user and group ID before running the editor.
The
pw_prompt()
function asks the user whether he or she wants to re-edit the password file;
if the answer is no, pw_prompt() deletes the lock
file and exits the process.
The
pw_copy()
function reads a passwd file from ffd and writes it to
tfd, updating the entry corresponding to
pw->pw_name with the information in pw. If
old_pw is not NULL, it checks
to make sure the old entry is the same as the one described in
old_pw or the process is aborted. If an entry is not
found to match pw, a new entry is appended to the
passwd file only if the real user ID is 0. If an error occurs,
pw_copy() will display a message on
stderr and call
pw_error().
The
pw_copyx()
function performs the same operation as pw_copy()
with the exception of error handling. Upon an error,
pw_copyx() will write an error message into the
buffer pointed to by errbuf which has the size
errbufsz.
The
pw_scan()
function accepts in bp a passwd entry as it would be
represented in /etc/master.passwd and fills in
pw with corresponding values; string fields in
pw will be pointers into bp.
Some characters in bp will be overwritten with 0s in
order to terminate the strings pointed to by pw. If
flags is non-null, it should be cleared and the
following options enabled if required:
_PASSWORD_NOWARN- Don't print warnings.
_PASSWORD_OLDFMT- Parse bp as an old format entry as found in /etc/passwd.
Upon return it is cleared, and filled in with the following flags:
_PASSWORD_NOUID- The uid field of bp is empty.
_PASSWORD_NOGID- The gid field of bp is empty.
_PASSWORD_NOCHG- The change field of bp is empty.
_PASSWORD_NOEXP- The expire field of bp is empty.
The
pw_error()
function displays an error message, aborts the current passwd update, and
exits the current process. If err is non-zero, a
warning message beginning with name is printed for the
current value of errno. The process exits with status
eval.
RETURN VALUES
The pw_copyx() function returns 1 if the
new password entry was successfully written to the destination file, and 0
otherwise.
The pw_scan() function prints a warning
message and returns 0 if the string in the bp argument
is not a valid passwd string. Otherwise, pw_scan()
returns 1.
FILES
- /etc/master.passwd
- /etc/ptmp