PW_INIT(3) | 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 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

# SEE ALSO

pw_lock(3), passwd(5)

August 1, 2004 | NetBSD 11.0