pw_scan(3) - NetBSD Manual Pages

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PW_INIT(3)              NetBSD Library Functions Manual             PW_INIT(3)


NAME

     pw_init, pw_edit, pw_prompt, pw_copy, pw_copyx, pw_scan, pw_error --
     utility functions for interactive passwd file updates


LIBRARY

     System Utilities Library (libutil, -lutil)


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 possi-
     bly 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 dis-
     abling 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 repre-
     sented 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 success-
     fully 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


SEE ALSO

     pw_lock(3), passwd(5)

NetBSD 10.1                     August 1, 2004                     NetBSD 10.1