dict_open.c

[詳解]

/*++
/* NAME
/*  dict_open 3
/* SUMMARY
/*  low-level dictionary interface
/* SYNOPSIS
/*  #include <dict.h>
/*
/*  DICT    *dict_open(dict_spec, open_flags, dict_flags)
/*  const char *dict_spec;
/*  int open_flags;
/*  int dict_flags;
/*
/*  DICT    *dict_open3(dict_type, dict_name, open_flags, dict_flags)
/*  const char *dict_type;
/*  const char *dict_name;
/*  int open_flags;
/*  int dict_flags;
/*
/*  int dict_put(dict, key, value)
/*  DICT    *dict;
/*  const char *key;
/*  const char *value;
/*
/*  const char *dict_get(dict, key)
/*  DICT    *dict;
/*  const char *key;
/*
/*  int dict_del(dict, key)
/*  DICT    *dict;
/*  const char *key;
/*
/*  int dict_seq(dict, func, key, value)
/*  DICT    *dict;
/*  int func;
/*  const char **key;
/*  const char **value;
/*
/*  void    dict_close(dict)
/*  DICT    *dict;
/*
/*  typedef DICT *(*DICT_OPEN_FN) (const char *, int, int);
/*
/*  dict_open_register(type, open)
/*  const char *type;
/*  DICT_OPEN_FN open;
/*
/*  typedef DICT_OPEN_FN (*DICT_OPEN_EXTEND_FN)(const char *type);
/*
/*  DICT_OPEN_EXTEND_FN dict_open_extend(call_back)
/*  DICT_OPEN_EXTEND_FN call_back;
/*
/*  ARGV    *dict_mapnames()
/*
/*  typedef ARGV *(*DICT_MAPNAMES_EXTEND_FN)(ARGV *names);
/*
/*  DICT_MAPNAMES_EXTEND_FN dict_mapnames_extend(call_back)
/*  DICT_MAPNAMES_EXTEND_FN call_back;
/*
/*  int dict_isjmp(dict)
/*  DICT    *dict;
/*
/*  int dict_setjmp(dict)
/*  DICT    *dict;
/*
/*  int dict_longjmp(dict, val)
/*  DICT    *dict;
/*  int val;
/*
/*  void    dict_type_override(dict, type)
/*  DICT    *dict;
/*  const char *type;
/* DESCRIPTION
/*  This module implements a low-level interface to multiple
/*  physical dictionary types.
/*
/*  dict_open() takes a type:name pair that specifies a dictionary type
/*  and dictionary name, opens the dictionary, and returns a dictionary
/*  handle.  The \fIopen_flags\fR arguments are as in open(2). The
/*  \fIdict_flags\fR are the bit-wise OR of zero or more of the following:
/* .IP DICT_FLAG_DUP_WARN
/*  Warn about duplicate keys, if the underlying database does not
/*  support duplicate keys. The default is to terminate with a fatal
/*  error.
/* .IP DICT_FLAG_DUP_IGNORE
/*  Ignore duplicate keys if the underlying database does not
/*  support duplicate keys. The default is to terminate with a fatal
/*  error.
/* .IP DICT_FLAG_DUP_REPLACE
/*  Replace duplicate keys if the underlying database supports such
/*  an operation. The default is to terminate with a fatal error.
/* .IP DICT_FLAG_TRY0NULL
/*  With maps where this is appropriate, append no null byte to
/*  keys and values.
/*  When neither DICT_FLAG_TRY0NULL nor DICT_FLAG_TRY1NULL are
/*  specified, the software guesses what format to use for reading;
/*  and in the absence of definite information, a system-dependent
/*  default is chosen for writing.
/* .IP DICT_FLAG_TRY1NULL
/*  With maps where this is appropriate, append one null byte to
/*  keys and values.
/*  When neither DICT_FLAG_TRY0NULL nor DICT_FLAG_TRY1NULL are
/*  specified, the software guesses what format to use for reading;
/*  and in the absence of definite information, a system-dependent
/*  default is chosen for writing.
/* .IP DICT_FLAG_LOCK
/*  With maps where this is appropriate, acquire an exclusive lock
/*  before writing, and acquire a shared lock before reading.
/*  Release the lock when the operation completes.
/* .IP DICT_FLAG_OPEN_LOCK
/*  The behavior of this flag depends on whether a database
/*  sets the DICT_FLAG_MULTI_WRITER flag to indicate that it
/*  is multi-writer safe.
/*
/*  With databases that are not multi-writer safe, dict_open()
/*  acquires a persistent exclusive lock, or it terminates with
/*  a fatal run-time error.
/*
/*  With databases that are multi-writer safe, dict_open()
/*  downgrades the DICT_FLAG_OPEN_LOCK flag (persistent lock)
/*  to DICT_FLAG_LOCK (temporary lock).
/* .IP DICT_FLAG_FOLD_FIX
/*  With databases whose lookup fields are fixed-case strings,
/*  fold the search string to lower case before accessing the
/*  database.  This includes hash:, cdb:, dbm:. nis:, ldap:,
/*  *sql. WARNING: case folding is supported only for ASCII or
/*  valid UTF-8.
/* .IP DICT_FLAG_FOLD_MUL
/*  With databases where one lookup field can match both upper
/*  and lower case, fold the search key to lower case before
/*  accessing the database. This includes regexp: and pcre:.
/*  WARNING: case folding is supported only for ASCII or valid
/*  UTF-8.
/* .IP DICT_FLAG_FOLD_ANY
/*  Short-hand for (DICT_FLAG_FOLD_FIX | DICT_FLAG_FOLD_MUL).
/* .IP DICT_FLAG_SYNC_UPDATE
/*  With file-based maps, flush I/O buffers to file after each update.
/*  Thus feature is not supported with some file-based dictionaries.
/* .IP DICT_FLAG_NO_REGSUB
/*  Disallow regular expression substitution from the lookup string
/*  into the lookup result, to block data injection attacks.
/* .IP DICT_FLAG_NO_PROXY
/*  Disallow access through the unprivileged \fBproxymap\fR
/*  service, to block privilege escalation attacks.
/* .IP DICT_FLAG_NO_UNAUTH
/*  Disallow lookup mechanisms that lack any form of authentication,
/*  to block privilege escalation attacks (example: tcp_table;
/*  even NIS can be secured to some extent by requiring that
/*  the server binds to a privileged port).
/* .IP DICT_FLAG_PARANOID
/*  A combination of all the paranoia flags: DICT_FLAG_NO_REGSUB,
/*  DICT_FLAG_NO_PROXY and DICT_FLAG_NO_UNAUTH.
/* .IP DICT_FLAG_BULK_UPDATE
/*  Enable preliminary code for bulk-mode database updates.
/*  The caller must create an exception handler with dict_jmp_alloc()
/*  and must trap exceptions from the database client with dict_setjmp().
/* .IP DICT_FLAG_DEBUG
/*  Enable additional logging.
/* .IP DICT_FLAG_UTF8_REQUEST
/*  With util_utf8_enable != 0, require that lookup/update/delete
/*  keys and values are valid UTF-8. Skip a lookup/update/delete
/*  request with a non-UTF-8 key, skip an update request with
/*  a non-UTF-8 value, and fail a lookup request with a non-UTF-8
/*  value.
/* .PP
/*  Specify DICT_FLAG_NONE for no special processing.
/*
/*  The dictionary types are as follows:
/* .IP environ
/*  The process environment array. The \fIdict_name\fR argument is ignored.
/* .IP dbm
/*  DBM file.
/* .IP hash
/*  Berkeley DB file in hash format.
/* .IP btree
/*  Berkeley DB file in btree format.
/* .IP nis
/*  NIS map. Only read access is supported.
/* .IP nisplus
/*  NIS+ map. Only read access is supported.
/* .IP netinfo
/*  NetInfo table. Only read access is supported.
/* .IP ldap
/*  LDAP ("light-weight" directory access protocol) database access.
/* .IP pcre
/*  PERL-compatible regular expressions.
/* .IP regexp
/*  POSIX-compatible regular expressions.
/* .IP texthash
/*  Flat text in postmap(1) input format.
/* .PP
/*  dict_open3() takes separate arguments for dictionary type and
/*  name, but otherwise performs the same functions as dict_open().
/*
/*  The dict_get(), dict_put(), dict_del(), and dict_seq()
/*  macros evaluate their first argument multiple times.
/*  These names should have been in uppercase.
/*
/*  dict_get() retrieves the value stored in the named dictionary
/*  under the given key. A null pointer means the value was not found.
/*  As with dict_lookup(), the result is owned by the lookup table
/*  implementation. Make a copy if the result is to be modified,
/*  or if the result is to survive multiple table lookups.
/*
/*  dict_put() stores the specified key and value into the named
/*  dictionary. A zero (DICT_STAT_SUCCESS) result means the
/*  update was made.
/*
/*  dict_del() removes a dictionary entry, and returns
/*  DICT_STAT_SUCCESS in case of success.
/*
/*  dict_seq() iterates over all members in the named dictionary.
/*  func is define DICT_SEQ_FUN_FIRST (select first member) or
/*  DICT_SEQ_FUN_NEXT (select next member). A zero (DICT_STAT_SUCCESS)
/*  result means that an entry was found.
/*
/*  dict_close() closes the specified dictionary and cleans up the
/*  associated data structures.
/*
/*  dict_open_register() adds support for a new dictionary type.
/*
/*  dict_open_extend() registers a call-back function that looks
/*  up the dictionary open() function for a type that is not
/*  registered, or null in case of error. The result value is
/*  the last previously-registered call-back or null.
/*
/*  dict_mapnames() returns a sorted list with the names of all available
/*  dictionary types.
/*
/*  dict_mapnames_extend() registers a call-back function that
/*  enumerates additional dictionary type names. The result
/*  will be sorted by dict_mapnames().  The result value
/*  is the last previously-registered call-back or null.
/*
/*  dict_setjmp() saves processing context and makes that context
/*  available for use with dict_longjmp().  Normally, dict_setjmp()
/*  returns zero.  A non-zero result means that dict_setjmp()
/*  returned through a dict_longjmp() call; the result is the
/*  \fIval\fR argument given to dict_longjmp(). dict_isjmp()
/*  returns non-zero when dict_setjmp() and dict_longjmp()
/*  are enabled for a given dictionary.
/*
/*  NB: non-local jumps such as dict_longjmp() are not safe for
/*  jumping out of any routine that manipulates DICT data.
/*  longjmp() like calls are best avoided in signal handlers.
/*
/*  dict_type_override() changes the symbolic dictionary type.
/*  This is used by dictionaries whose internals are based on
/*  some other dictionary type.
/* DIAGNOSTICS
/*  Fatal error: open error, unsupported dictionary type, attempt to
/*  update non-writable dictionary.
/*
/*  The lookup routine returns non-null when the request is
/*  satisfied. The update, delete and sequence routines return
/*  zero (DICT_STAT_SUCCESS) when the request is satisfied.
/*  The dict->errno value is non-zero only when the last operation
/*  was not satisfied due to a dictionary access error. This
/*  can have the following values:
/* .IP DICT_ERR_NONE(zero)
/*  There was no dictionary access error. For example, the
/*  request was satisfied, the requested information did not
/*  exist in the dictionary, or the information already existed
/*  when it should not exist (collision).
/* .IP DICT_ERR_RETRY(<0)
/*  The dictionary was temporarily unavailable. This can happen
/*  with network-based services.
/* .IP DICT_ERR_CONFIG(<0)
/*  The dictionary was unavailable due to a configuration error.
/* .PP
/*  Generally, a program is expected to test the function result
/*  value for "success" first. If the operation was not successful,
/*  a program is expected to test for a non-zero dict->error
/*  status to distinguish between a data notfound/collision
/*  condition or a dictionary access error.
/* LICENSE
/* .ad
/* .fi
/*  The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/*  Wietse Venema
/*  IBM T.J. Watson Research
/*  P.O. Box 704
/*  Yorktown Heights, NY 10598, USA
/*
/*  Wietse Venema
/*  Google, Inc.
/*  111 8th Avenue
/*  New York, NY 10011, USA
/*--*/

/* System library. */

#include <sys_defs.h>
#include <string.h>
#include <stdlib.h>

/* Utility library. */

#include <argv.h>
#include <mymalloc.h>
#include <msg.h>
#include <dict.h>
#include <dict_cdb.h>
#include <dict_env.h>
#include <dict_unix.h>
#include <dict_tcp.h>
#include <dict_sdbm.h>
#include <dict_dbm.h>
#include <dict_db.h>
#include <dict_lmdb.h>
#include <dict_nis.h>
#include <dict_nisplus.h>
#include <dict_ni.h>
#include <dict_pcre.h>
#include <dict_regexp.h>
#include <dict_static.h>
#include <dict_cidr.h>
#include <dict_ht.h>
#include <dict_thash.h>
#include <dict_sockmap.h>
#include <dict_fail.h>
#include <dict_pipe.h>
#include <dict_random.h>
#include <dict_union.h>
#include <dict_inline.h>
#include <stringops.h>
#include <split_at.h>
#include <htable.h>
#include <myflock.h>

 /*
  * lookup table for available map types.
  */
typedef struct {
    char   *type;
    DICT_OPEN_FN open;
} DICT_OPEN_INFO;

static const DICT_OPEN_INFO dict_open_info[] = {
    DICT_TYPE_ENVIRON, dict_env_open,
    DICT_TYPE_HT, dict_ht_open,
    DICT_TYPE_UNIX, dict_unix_open,
    DICT_TYPE_TCP, dict_tcp_open,
#ifdef HAS_DBM
    DICT_TYPE_DBM, dict_dbm_open,
#endif
#ifdef HAS_DB
    DICT_TYPE_HASH, dict_hash_open,
    DICT_TYPE_BTREE, dict_btree_open,
#endif
#ifdef HAS_NIS
    DICT_TYPE_NIS, dict_nis_open,
#endif
#ifdef HAS_NISPLUS
    DICT_TYPE_NISPLUS, dict_nisplus_open,
#endif
#ifdef HAS_NETINFO
    DICT_TYPE_NETINFO, dict_ni_open,
#endif
#ifdef HAS_POSIX_REGEXP
    DICT_TYPE_REGEXP, dict_regexp_open,
#endif
    DICT_TYPE_STATIC, dict_static_open,
    DICT_TYPE_CIDR, dict_cidr_open,
    DICT_TYPE_THASH, dict_thash_open,
    DICT_TYPE_SOCKMAP, dict_sockmap_open,
    DICT_TYPE_FAIL, dict_fail_open,
    DICT_TYPE_PIPE, dict_pipe_open,
    DICT_TYPE_RANDOM, dict_random_open,
    DICT_TYPE_UNION, dict_union_open,
    DICT_TYPE_INLINE, dict_inline_open,
#ifndef USE_DYNAMIC_MAPS
#ifdef HAS_PCRE
    DICT_TYPE_PCRE, dict_pcre_open,
#endif
#ifdef HAS_CDB
    DICT_TYPE_CDB, dict_cdb_open,
#endif
#ifdef HAS_SDBM
    DICT_TYPE_SDBM, dict_sdbm_open,
#endif
#ifdef HAS_LMDB
    DICT_TYPE_LMDB, dict_lmdb_open,
#endif
#endif                  /* !USE_DYNAMIC_MAPS */
    0,
};

static HTABLE *dict_open_hash;

 /*
  * Extension hooks.
  */
static DICT_OPEN_EXTEND_FN dict_open_extend_hook;
static DICT_MAPNAMES_EXTEND_FN dict_mapnames_extend_hook;

 /*
  * Workaround.
  */
DEFINE_DICT_LMDB_MAP_SIZE;
DEFINE_DICT_DB_CACHE_SIZE;

/* dict_open_init - one-off initialization */

static void dict_open_init(void)
{
    const char *myname = "dict_open_init";
    const DICT_OPEN_INFO *dp;

    if (dict_open_hash != 0)
    msg_panic("%s: multiple initialization", myname);
    dict_open_hash = htable_create(10);

    for (dp = dict_open_info; dp->type; dp++)
    htable_enter(dict_open_hash, dp->type, (void *) dp);
}

/* dict_open - open dictionary */

DICT   *dict_open(const char *dict_spec, int open_flags, int dict_flags)
{
    char   *saved_dict_spec = mystrdup(dict_spec);
    char   *dict_name;
    DICT   *dict;

    if ((dict_name = split_at(saved_dict_spec, ':')) == 0)
    msg_fatal("open dictionary: expecting \"type:name\" form instead of \"%s\"",
          dict_spec);

    dict = dict_open3(saved_dict_spec, dict_name, open_flags, dict_flags);
    myfree(saved_dict_spec);
    return (dict);
}


/* dict_open3 - open dictionary */

DICT   *dict_open3(const char *dict_type, const char *dict_name,
                   int open_flags, int dict_flags)
{
    const char *myname = "dict_open";
    DICT_OPEN_INFO *dp;
    DICT_OPEN_FN open_fn;
    DICT   *dict;

    if (*dict_type == 0 || *dict_name == 0)
    msg_fatal("open dictionary: expecting \"type:name\" form instead of \"%s:%s\"",
          dict_type, dict_name);
    if (dict_open_hash == 0)
    dict_open_init();
    if ((dp = (DICT_OPEN_INFO *) htable_find(dict_open_hash, dict_type)) == 0) {
    if (dict_open_extend_hook != 0
        && (open_fn = dict_open_extend_hook(dict_type)) != 0) {
        dict_open_register(dict_type, open_fn);
        dp = (DICT_OPEN_INFO *) htable_find(dict_open_hash, dict_type);
    }
    if (dp == 0)
        return (dict_surrogate(dict_type, dict_name, open_flags, dict_flags,
                 "unsupported dictionary type: %s", dict_type));
    }
    if ((dict = dp->open(dict_name, open_flags, dict_flags)) == 0)
    return (dict_surrogate(dict_type, dict_name, open_flags, dict_flags,
                "cannot open %s:%s: %m", dict_type, dict_name));
    if (msg_verbose)
    msg_info("%s: %s:%s", myname, dict_type, dict_name);
    /* XXX The choice between wait-for-lock or no-wait is hard-coded. */
    if (dict->flags & DICT_FLAG_OPEN_LOCK) {
    if (dict->flags & DICT_FLAG_LOCK)
        msg_panic("%s: attempt to open %s:%s with both \"open\" lock and \"access\" lock",
              myname, dict_type, dict_name);
    /* Multi-writer safe map: downgrade persistent lock to temporary. */
    if (dict->flags & DICT_FLAG_MULTI_WRITER) {
        dict->flags &= ~DICT_FLAG_OPEN_LOCK;
        dict->flags |= DICT_FLAG_LOCK;
    }
    /* Multi-writer unsafe map: acquire exclusive lock or bust. */
    else if (dict->lock(dict, MYFLOCK_OP_EXCLUSIVE | MYFLOCK_OP_NOWAIT) < 0)
        msg_fatal("%s:%s: unable to get exclusive lock: %m",
              dict_type, dict_name);
    }
    /* Last step: insert proxy for UTF-8 syntax checks and casefolding. */
    if ((dict->flags & DICT_FLAG_UTF8_ACTIVE) == 0
    && DICT_NEED_UTF8_ACTIVATION(util_utf8_enable, dict_flags))
    dict = dict_utf8_activate(dict);
    return (dict);
}

/* dict_open_register - register dictionary type */

void    dict_open_register(const char *type, DICT_OPEN_FN open)
{
    const char *myname = "dict_open_register";
    DICT_OPEN_INFO *dp;
    HTABLE_INFO *ht;

    if (dict_open_hash == 0)
    dict_open_init();
    if (htable_find(dict_open_hash, type))
    msg_panic("%s: dictionary type exists: %s", myname, type);
    dp = (DICT_OPEN_INFO *) mymalloc(sizeof(*dp));
    dp->open = open;
    ht = htable_enter(dict_open_hash, type, (void *) dp);
    dp->type = ht->key;
}

/* dict_open_extend - register alternate dictionary search routine */

DICT_OPEN_EXTEND_FN dict_open_extend(DICT_OPEN_EXTEND_FN new_cb)
{
    DICT_OPEN_EXTEND_FN old_cb;

    old_cb = dict_open_extend_hook;
    dict_open_extend_hook = new_cb;
    return (old_cb);
}

/* dict_sort_alpha_cpp - qsort() callback */

static int dict_sort_alpha_cpp(const void *a, const void *b)
{
    return (strcmp(((char **) a)[0], ((char **) b)[0]));
}

/* dict_mapnames - return an ARGV of available map_names */

ARGV   *dict_mapnames()
{
    HTABLE_INFO **ht_info;
    HTABLE_INFO **ht;
    DICT_OPEN_INFO *dp;
    ARGV   *mapnames;

    if (dict_open_hash == 0)
    dict_open_init();
    mapnames = argv_alloc(dict_open_hash->used + 1);
    for (ht_info = ht = htable_list(dict_open_hash); *ht; ht++) {
    dp = (DICT_OPEN_INFO *) ht[0]->value;
    argv_add(mapnames, dp->type, ARGV_END);
    }
    if (dict_mapnames_extend_hook != 0)
    (void) dict_mapnames_extend_hook(mapnames);
    qsort((void *) mapnames->argv, mapnames->argc, sizeof(mapnames->argv[0]),
      dict_sort_alpha_cpp);
    myfree((void *) ht_info);
    argv_terminate(mapnames);
    return mapnames;
}

/* dict_mapnames_extend - register alternate dictionary type list routine */

DICT_MAPNAMES_EXTEND_FN dict_mapnames_extend(DICT_MAPNAMES_EXTEND_FN new_cb)
{
    DICT_MAPNAMES_EXTEND_FN old_cb;

    old_cb = dict_mapnames_extend_hook;
    dict_mapnames_extend_hook = new_cb;
    return (old_cb);
}

/* dict_type_override - disguise a dictionary type */

void    dict_type_override(DICT *dict, const char *type)
{
    myfree(dict->type);
    dict->type = mystrdup(type);
}

#ifdef TEST

 /*
  * Proof-of-concept test program.
  */
int     main(int argc, char **argv)
{
    dict_test(argc, argv);
    return (0);
}

#endif