mapc.c

早期freebsd实现

/*-
 * Copyright (c) 1989 Jan-Simon Pendry
 * Copyright (c) 1989 Imperial College of Science, Technology & Medicine
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Jan-Simon Pendry at Imperial College, London.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $Id: mapc.c,v 5.2.2.1 1992/02/09 15:08:38 jsp beta $
 */

#ifndef lint
static char sccsid[] = "@(#)mapc.c	8.1 (Berkeley) 6/6/93";
#endif /* not lint */

/*
 * Mount map cache
 */

#include "am.h"
#ifdef HAS_REGEXP
#include RE_HDR
#endif

/*
 * Hash table size
 */
#define	NKVHASH	(1 << 2)		/* Power of two */

/*
 * Wildcard key
 */
static char wildcard[] = "*";

/*
 * Map cache types
 * default, none, incremental, all, regexp
 * MAPC_RE implies MAPC_ALL and must be numerically
 * greater.
 */
#define	MAPC_DFLT	0x000
#define	MAPC_NONE	0x001
#define	MAPC_INC	0x002
#define	MAPC_ROOT	0x004
#define	MAPC_ALL	0x010
#ifdef HAS_REGEXP
#define MAPC_RE		0x020
#define	MAPC_ISRE(m) ((m)->alloc == MAPC_RE)
#else
#define MAPC_ISRE(m) FALSE
#endif
#define	MAPC_CACHE_MASK	0x0ff
#define	MAPC_SYNC	0x100

static struct opt_tab mapc_opt[] = {
	{ "all", MAPC_ALL },
	{ "default", MAPC_DFLT },
	{ "inc", MAPC_INC },
	{ "mapdefault", MAPC_DFLT },
	{ "none", MAPC_NONE },
#ifdef HAS_REGEXP
	{ "re", MAPC_RE },
	{ "regexp", MAPC_RE },
#endif
	{ "sync", MAPC_SYNC },
	{ 0, 0 }
};

/*
 * Lookup recursion
 */
#define	MREC_FULL	2
#define	MREC_PART	1
#define	MREC_NONE	0

/*
 * Cache map operations
 */
typedef void add_fn P((mnt_map*, char*, char*));
typedef int init_fn P((char*, time_t*));
typedef int search_fn P((mnt_map*, char*, char*, char**, time_t*));
typedef int reload_fn P((mnt_map*, char*, add_fn*));
typedef int mtime_fn P((char*, time_t*));

static void mapc_sync P((mnt_map*));

/*
 * Map type
 */
typedef struct map_type map_type;
struct map_type {
	char *name;			/* Name of this map type */
	init_fn *init;			/* Initialisation */
	reload_fn *reload;		/* Reload or fill */
	search_fn *search;		/* Search for new entry */
	mtime_fn *mtime;		/* Find modify time */
	int def_alloc;			/* Default allocation mode */
};

/*
 * Key-value pair
 */
typedef struct kv kv;
struct kv {
	kv *next;
	char *key;
	char *val;
};

struct mnt_map {
	qelem hdr;
	int refc;			/* Reference count */
	short flags;			/* Allocation flags */
	short alloc;			/* Allocation mode */
	time_t modify;			/* Modify time of map */
	char *map_name;			/* Name of this map */
	char *wildcard;			/* Wildcard value */
	reload_fn *reload;		/* Function to be used for reloads */
	search_fn *search;		/* Function to be used for searching */
	mtime_fn *mtime;		/* Modify time function */
	kv *kvhash[NKVHASH];		/* Cached data */
};

/*
 * Map for root node
 */
static mnt_map *root_map;

/*
 * List of known maps
 */
extern qelem map_list_head;
qelem map_list_head = { &map_list_head, &map_list_head };

/*
 * Configuration
 */
 
/* ROOT MAP */
static int root_init P((char*, time_t*));

/* FILE MAPS */
#ifdef HAS_FILE_MAPS
extern int file_init P((char*, time_t*));
extern int file_reload P((mnt_map*, char*, add_fn*));
extern int file_search P((mnt_map*, char*, char*, char**, time_t*));
extern int file_mtime P((char*, time_t*));
#endif /* HAS_FILE_MAPS */

/* Network Information Service (NIS) MAPS */
#ifdef HAS_NIS_MAPS
extern int nis_init P((char*, time_t*));
#ifdef HAS_NIS_RELOAD
extern int nis_reload P((mnt_map*, char*, add_fn*));
#else
#define nis_reload error_reload
#endif
extern int nis_search P((mnt_map*, char*, char*, char**, time_t*));
#define nis_mtime nis_init
#endif /* HAS_NIS_MAPS */

/* NDBM MAPS */
#ifdef HAS_NDBM_MAPS
#ifdef OS_HAS_NDBM
extern int ndbm_init P((char*, time_t*));
extern int ndbm_search P((mnt_map*, char*, char*, char**, time_t*));
#define ndbm_mtime ndbm_init
#endif /* OS_HAS_NDBM */
#endif /* HAS_NDBM_MAPS */

/* PASSWD MAPS */
#ifdef HAS_PASSWD_MAPS
extern int passwd_init P((char*, time_t*));
extern int passwd_search P((mnt_map*, char*, char*, char**, time_t*));
#endif /* HAS_PASSWD_MAPS */

/* HESIOD MAPS */
#ifdef HAS_HESIOD_MAPS
extern int hesiod_init P((char*, time_t*));
#ifdef HAS_HESIOD_RELOAD
extern int hesiod_reload P((mnt_map*, char*, add_fn*));
#else
#define hesiod_reload error_reload
#endif
extern int hesiod_search P((mnt_map*, char*, char*, char**, time_t*));
#endif /* HAS_HESIOD_MAPS */

/* UNION MAPS */
#ifdef HAS_UNION_MAPS
extern int union_init P((char*, time_t*));
extern int union_search P((mnt_map*, char*, char*, char**, time_t*));
extern int union_reload P((mnt_map*, char*, add_fn*));
#endif /* HAS_UNION_MAPS */

/* ERROR MAP */
static int error_init P((char*, time_t*));
static int error_reload P((mnt_map*, char*, add_fn*));
static int error_search P((mnt_map*, char*, char*, char**, time_t*));
static int error_mtime P((char*, time_t*));

static map_type maptypes[] = {
	{ "root", root_init, error_reload, error_search, error_mtime, MAPC_ROOT },

#ifdef HAS_PASSWD_MAPS
	{ "passwd", passwd_init, error_reload, passwd_search, error_mtime, MAPC_INC },
#endif

#ifdef HAS_HESIOD_MAPS
	{ "hesiod", hesiod_init, hesiod_reload, hesiod_search, error_mtime, MAPC_ALL },
#endif

#ifdef HAS_UNION_MAPS
	{ "union", union_init, union_reload, union_search, error_mtime, MAPC_ALL },
#endif

#ifdef HAS_NIS_MAPS
	{ "nis", nis_init, nis_reload, nis_search, nis_mtime, MAPC_INC },
#endif

#ifdef HAS_NDBM_MAPS
	{ "ndbm", ndbm_init, error_reload, ndbm_search, ndbm_mtime, MAPC_INC },
#endif

#ifdef HAS_FILE_MAPS
	{ "file", file_init, file_reload, file_search, file_mtime, MAPC_ALL },
#endif

	{ "error", error_init, error_reload, error_search, error_mtime, MAPC_NONE },
};

/*
 * Hash function
 */
static unsigned int kvhash_of P((char *key));
static unsigned int kvhash_of(key)
char *key;
{
	unsigned int i, j;

	for (i = 0; j = *key++; i += j)
		;

	return i % NKVHASH;
}

void mapc_showtypes P((FILE *fp));
void mapc_showtypes(fp)
FILE *fp;
{
	map_type *mt;
	char *sep = "";
	for (mt = maptypes; mt < maptypes+sizeof(maptypes)/sizeof(maptypes[0]); mt++) {
		fprintf(fp, "%s%s", sep, mt->name);
		sep = ", ";
	}
}

static Const char *reg_error = "?";
void regerror P((Const char *m));
void regerror(m)
Const char *m;
{
	reg_error = m;
}

/*
 * Add key and val to the map m.
 * key and val are assumed to be safe copies
 */
void mapc_add_kv P((mnt_map *m, char *key, char *val));
void mapc_add_kv(m, key, val)
mnt_map *m;
char *key;
char *val;
{
	kv **h;
	kv *n;
	int hash = kvhash_of(key);

#ifdef DEBUG
	dlog("add_kv: %s -> %s", key, val);
#endif

#ifdef HAS_REGEXP
	if (MAPC_ISRE(m)) {
		char keyb[MAXPATHLEN];
		regexp *re;
		/*
		 * Make sure the string is bound to the start and end
		 */
		sprintf(keyb, "^%s$", key);
		re = regcomp(keyb);
		if (re == 0) {
			plog(XLOG_USER, "error compiling RE \"%s\": %s", keyb, reg_error);
			return;
		} else {
			free(key);
			key = (char *) re;
		}
	}
#endif

	h = &m->kvhash[hash];
	n = ALLOC(kv);
	n->key = key;
	n->val = val;
	n->next = *h;
	*h = n;
}

void mapc_repl_kv P((mnt_map *m, char *key, char *val));
void mapc_repl_kv(m, key, val)
mnt_map *m;
char *key;
char *val;
{
	kv *k;

	/*
	 * Compute the hash table offset
	 */
	k = m->kvhash[kvhash_of(key)];

	/*
	 * Scan the linked list for the key
	 */
	while (k && !FSTREQ(k->key, key))
		k = k->next;

	if (k) {
		free(k->val);
		k->val = val;
	} else {
		mapc_add_kv(m, key, val);
	}

}

/*
 * Search a map for a key.
 * Calls map specific search routine.
 * While map is out of date, keep re-syncing.
 */
static int search_map P((mnt_map *m, char *key, char **valp));
static int search_map(m, key, valp)
mnt_map *m;
char *key;
char **valp;
{
	int rc;
	do {
		rc = (*m->search)(m, m->map_name, key, valp, &m->modify);
		if (rc < 0) {
			plog(XLOG_MAP, "Re-synchronizing cache for map %s", m->map_name);
			mapc_sync(m);
		}
	} while (rc < 0);

	return rc;
}

/*
 * Do a wildcard lookup in the map and
 * save the result.
 */
static void mapc_find_wildcard P((mnt_map *m));
static void mapc_find_wildcard(m)
mnt_map *m;
{
	/*
	 * Attempt to find the wildcard entry
	 */
	int rc = search_map(m, wildcard, &m->wildcard);

	if (rc != 0)
		m->wildcard = 0;
}

/*
 * Make a duplicate reference to an existing map
 */
#define mapc_dup(m) ((m)->refc++, (m))

/*
 * Do a map reload
 */
static int mapc_reload_map(m)
mnt_map *m;
{
	int error;
#ifdef DEBUG
	dlog("calling map reload on %s", m->map_name);
#endif
	error = (*m->reload)(m, m->map_name, mapc_add_kv);
	if (error)
		return error;
	m->wildcard = 0;
#ifdef DEBUG
	dlog("calling mapc_search for wildcard");
#endif
	error = mapc_search(m, wildcard, &m->wildcard);
	if (error)
		m->wildcard = 0;
	return 0;
}

/*
 * Create a new map
 */
static mnt_map *mapc_create P((char *map, char *opt));
static mnt_map *mapc_create(map, opt)
char *map;
char *opt;
{
	mnt_map *m = ALLOC(mnt_map);
	map_type *mt;
	time_t modify;
	int alloc = 0;

	(void) cmdoption(opt, mapc_opt, &alloc);

	for (mt = maptypes; mt < maptypes+sizeof(maptypes)/sizeof(maptypes[0]); mt++)
		if ((*mt->init)(map, &modify) == 0)
			break;
	/* assert: mt in maptypes */

	m->flags = alloc & ~MAPC_CACHE_MASK;
	alloc &= MAPC_CACHE_MASK;