shadow/lib/commonio.h
ed neville 65470e5c7d changing lock mechanism
Systems can suffer power interruptions whilst .lock files are in /etc,
preventing scripts and other automation tools from updating shadow's
files which persist across boots.

This commit replaces that mechanism with file locking to avoid problems
of power interruption/crashing.

Minor tweak to groupmems man page, requested by 'xx' on IRC.

Signed-off-by: ed neville <ed@s5h.net>
2022-12-29 13:58:49 -06:00

146 lines
3.9 KiB
C

/*
* SPDX-FileCopyrightText: 1990 - 1994, Julianne Frances Haugh
* SPDX-FileCopyrightText: 1996 - 2000, Marek Michałkiewicz
* SPDX-FileCopyrightText: 2001 - 2005, Tomasz Kłoczko
* SPDX-FileCopyrightText: 2007 - 2010, Nicolas François
*
* SPDX-License-Identifier: BSD-3-Clause
*/
/* $Id$ */
#ifndef COMMONIO_H
#define COMMONIO_H
#include "defines.h" /* bool */
/*
* Linked list entry.
*/
struct commonio_entry {
/*@null@*/char *line;
/*@null@*/void *eptr; /* struct passwd, struct spwd, ... */
/*@dependent@*/ /*@null@*/struct commonio_entry *prev;
/*@owned@*/ /*@null@*/struct commonio_entry *next;
bool changed:1;
};
/*
* Operations depending on database type: passwd, group, shadow etc.
*/
struct commonio_ops {
/*
* Make a copy of the object (for example, struct passwd)
* and all strings pointed by it, in malloced memory.
*/
/*@null@*/ /*@only@*/void *(*dup) (const void *);
/*
* free() the object including any strings pointed by it.
*/
void (*free) (/*@out@*/ /*@only@*/void *);
/*
* Return the name of the object (for example, pw_name
* for struct passwd).
*/
const char *(*getname) (const void *);
/*
* Parse a string, return object (in static area -
* should be copied using the dup operation above).
*/
void *(*parse) (const char *);
/*
* Write the object to the file (this calls putpwent()
* for struct passwd, for example).
*/
int (*put) (const void *, FILE *);
/*
* fgets and fputs (can be replaced by versions that
* understand line continuation conventions).
*/
/*@null@*/char *(*fgets) (/*@returned@*/ /*@out@*/char *s, int n, FILE *stream);
int (*fputs) (const char *, FILE *);
/*
* open_hook and close_hook.
* If non NULL, these functions will be called after the database
* is open or before it is closed.
* They return 0 on failure and 1 on success.
*/
/*@null@*/int (*open_hook) (void);
/*@null@*/int (*close_hook) (void);
};
/*
* Database structure.
*/
struct commonio_db {
/*
* Name of the data file.
*/
char filename[1024];
/*
* Operations from above.
*/
/*@observer@*/const struct commonio_ops *ops;
/*
* Currently open file stream.
*/
/*@dependent@*/ /*@null@*/FILE *fp;
#ifdef WITH_SELINUX
/*@null@*/char *scontext;
#endif
/*
* Default permissions and owner for newly created data file.
*/
mode_t st_mode;
uid_t st_uid;
gid_t st_gid;
/*
* Head, tail, current position in linked list.
*/
/*@owned@*/ /*@null@*/struct commonio_entry *head;
/*@dependent@*/ /*@null@*/struct commonio_entry *tail;
/*@dependent@*/ /*@null@*/struct commonio_entry *cursor;
/*
* Various flags.
*/
bool changed:1;
bool isopen:1;
bool locked:1;
bool readonly:1;
bool setname:1;
};
extern int commonio_setname (struct commonio_db *, const char *);
extern bool commonio_present (const struct commonio_db *db);
extern int commonio_lock (struct commonio_db *);
extern int commonio_lock_nowait (struct commonio_db *, bool log);
extern int do_fcntl_lock (const char *file, bool log, short type);
extern int commonio_open (struct commonio_db *, int);
extern /*@observer@*/ /*@null@*/const void *commonio_locate (struct commonio_db *, const char *);
extern int commonio_update (struct commonio_db *, const void *);
#ifdef ENABLE_SUBIDS
extern int commonio_append (struct commonio_db *, const void *);
#endif /* ENABLE_SUBIDS */
extern int commonio_remove (struct commonio_db *, const char *);
extern int commonio_rewind (struct commonio_db *);
extern /*@observer@*/ /*@null@*/const void *commonio_next (struct commonio_db *);
extern int commonio_close (struct commonio_db *);
extern int commonio_unlock (struct commonio_db *);
extern void commonio_del_entry (struct commonio_db *,
const struct commonio_entry *);
extern int commonio_sort_wrt (struct commonio_db *shadow,
const struct commonio_db *passwd);
extern int commonio_sort (struct commonio_db *db,
int (*cmp) (const void *, const void *));
#endif