dict.h

[詳解]

#ifndef _DICT_H_INCLUDED_
#define _DICT_H_INCLUDED_

/*++
/* NAME
/*  dict 3h
/* SUMMARY
/*  dictionary manager
/* SYNOPSIS
/*  #include <dict.h>
/* DESCRIPTION
/* .nf

 /*
  * System library.
  */
#include <fcntl.h>
#include <setjmp.h>

#ifdef NO_SIGSETJMP
#define DICT_JMP_BUF jmp_buf
#else
#define DICT_JMP_BUF sigjmp_buf
#endif

 /*
  * Utility library.
  */
#include <vstream.h>
#include <argv.h>
#include <vstring.h>
#include <myflock.h>

 /*
  * Provenance information.
  */
typedef struct DICT_OWNER {
    int     status;         /* see below */
    uid_t   uid;            /* use only if status == UNTRUSTED */
} DICT_OWNER;

 /*
  * Note that trust levels are not in numerical order.
  */
#define DICT_OWNER_UNKNOWN  (-1)    /* ex: unauthenticated tcp, proxy */
#define DICT_OWNER_TRUSTED  (!1)    /* ex: root-owned config file */
#define DICT_OWNER_UNTRUSTED    (!0)    /* ex: non-root config file */

 /*
  * When combining tables with different provenance, we initialize to the
  * highest trust level, and remember the lowest trust level that we find
  * during aggregation. If we combine tables that are owned by different
  * untrusted users, the resulting provenance is "unknown".
  */
#define DICT_OWNER_AGGREGATE_INIT(dst) { \
    (dst).status = DICT_OWNER_TRUSTED; \
    (dst).uid = 0; \
    } while (0)

 /*
  * The following is derived from the 3x3 transition matrix.
  */
#define DICT_OWNER_AGGREGATE_UPDATE(dst, src) do { \
    if ((dst).status == DICT_OWNER_TRUSTED \
        || (src).status == DICT_OWNER_UNKNOWN) { \
        (dst) = (src); \
    } else if ((dst).status == (src).status \
        && (dst).uid != (src).uid) { \
        (dst).status = DICT_OWNER_UNKNOWN; \
        (dst).uid = ~0; \
    } \
    } while (0)

 /*
  * Generic dictionary interface - in reality, a dictionary extends this
  * structure with private members to maintain internal state.
  */
typedef struct DICT {
    char   *type;           /* for diagnostics */
    char   *name;           /* for diagnostics */
    int     flags;          /* see below */
    const char *(*lookup) (struct DICT *, const char *);
    int     (*update) (struct DICT *, const char *, const char *);
    int     (*delete) (struct DICT *, const char *);
    int     (*sequence) (struct DICT *, int, const char **, const char **);
    int     (*lock) (struct DICT *, int);
    void    (*close) (struct DICT *);
    int     lock_type;          /* for read/write lock */
    int     lock_fd;            /* for read/write lock */
    int     stat_fd;            /* change detection */
    time_t  mtime;          /* mod time at open */
    VSTRING *fold_buf;          /* key folding buffer */
    DICT_OWNER owner;           /* provenance */
    int     error;          /* last operation only */
    DICT_JMP_BUF *jbuf;         /* exception handling */
    struct DICT_UTF8_BACKUP *utf8_backup;   /* see below */
} DICT;

extern DICT *dict_alloc(const char *, const char *, ssize_t);
extern void dict_free(DICT *);

extern DICT *dict_debug(DICT *);

#define DICT_DEBUG(d) ((d)->flags & DICT_FLAG_DEBUG ? dict_debug(d) : (d))

 /*
  * See dict_open.c embedded manpage for flag definitions.
  */
#define DICT_FLAG_NONE      (0)
#define DICT_FLAG_DUP_WARN  (1<<0)  /* warn about dups if not supported */
#define DICT_FLAG_DUP_IGNORE    (1<<1)  /* ignore dups if not supported */
#define DICT_FLAG_TRY0NULL  (1<<2)  /* do not append 0 to key/value */
#define DICT_FLAG_TRY1NULL  (1<<3)  /* append 0 to key/value */
#define DICT_FLAG_FIXED     (1<<4)  /* fixed key map */
#define DICT_FLAG_PATTERN   (1<<5)  /* keys are patterns */
#define DICT_FLAG_LOCK      (1<<6)  /* use temp lock before access */
#define DICT_FLAG_DUP_REPLACE   (1<<7)  /* replace dups if supported */
#define DICT_FLAG_SYNC_UPDATE   (1<<8)  /* sync updates if supported */
#define DICT_FLAG_DEBUG     (1<<9)  /* log access */
/*#define DICT_FLAG_FOLD_KEY    (1<<10) /* lowercase the lookup key */
#define DICT_FLAG_NO_REGSUB (1<<11) /* disallow regexp substitution */
#define DICT_FLAG_NO_PROXY  (1<<12) /* disallow proxy mapping */
#define DICT_FLAG_NO_UNAUTH (1<<13) /* disallow unauthenticated data */
#define DICT_FLAG_FOLD_FIX  (1<<14) /* case-fold key with fixed-case map */
#define DICT_FLAG_FOLD_MUL  (1<<15) /* case-fold key with multi-case map */
#define DICT_FLAG_FOLD_ANY  (DICT_FLAG_FOLD_FIX | DICT_FLAG_FOLD_MUL)
#define DICT_FLAG_OPEN_LOCK (1<<16) /* perm lock if not multi-writer safe */
#define DICT_FLAG_BULK_UPDATE   (1<<17) /* optimize for bulk updates */
#define DICT_FLAG_MULTI_WRITER  (1<<18) /* multi-writer safe map */
#define DICT_FLAG_UTF8_REQUEST  (1<<19) /* activate UTF-8 if possible */
#define DICT_FLAG_UTF8_ACTIVE   (1<<20) /* UTF-8 proxy layer is present */

#define DICT_FLAG_UTF8_MASK (DICT_FLAG_UTF8_REQUEST)

 /* IMPORTANT: Update the dict_mask[] table when the above changes */

 /*
  * The subsets of flags that control how a map is used. These are relevant
  * mainly for proxymap support. Note: some categories overlap.
  * 
  * DICT_FLAG_IMPL_MASK - flags that are set by the map implementation itself.
  * 
  * DICT_FLAG_PARANOID - requestor flags that forbid the use of insecure map
  * types for security-sensitive operations. These flags are checked by the
  * map implementation itself upon open, lookup etc. requests.
  * 
  * DICT_FLAG_RQST_MASK - all requestor flags, including paranoid flags, that
  * the requestor may change between open, lookup etc. requests. These
  * specify requestor properties, not map properties.
  * 
  * DICT_FLAG_INST_MASK - none of the above flags. The requestor may not change
  * these flags between open, lookup, etc. requests (although a map may make
  * changes to its copy of some of these flags). The proxymap server opens
  * only one map instance for all client requests with the same values of
  * these flags, and the proxymap client uses its own saved copy of these
  * flags.
  */
#define DICT_FLAG_PARANOID \
    (DICT_FLAG_NO_REGSUB | DICT_FLAG_NO_PROXY | DICT_FLAG_NO_UNAUTH)
#define DICT_FLAG_IMPL_MASK (DICT_FLAG_FIXED | DICT_FLAG_PATTERN | \
                DICT_FLAG_MULTI_WRITER)
#define DICT_FLAG_RQST_MASK (DICT_FLAG_FOLD_ANY | DICT_FLAG_LOCK | \
                DICT_FLAG_DUP_REPLACE | DICT_FLAG_DUP_WARN | \
                DICT_FLAG_DUP_IGNORE | DICT_FLAG_SYNC_UPDATE | \
                DICT_FLAG_PARANOID | DICT_FLAG_UTF8_MASK)
#define DICT_FLAG_INST_MASK ~(DICT_FLAG_IMPL_MASK | DICT_FLAG_RQST_MASK)

 /*
  * Feature tests.
  */
#define DICT_NEED_UTF8_ACTIVATION(enable, flags) \
    ((enable) && ((flags) & DICT_FLAG_UTF8_MASK))

 /*
  * dict->error values. Errors must be negative; smtpd_check depends on this.
  */
#define DICT_ERR_NONE   0       /* no error */
#define DICT_ERR_RETRY  (-1)        /* soft error */
#define DICT_ERR_CONFIG (-2)        /* configuration error */

 /*
  * Result values for exposed functions except lookup. FAIL/ERROR are
  * suggested values, not for use in comparisons for equality.
  */
#define DICT_STAT_FAIL      1   /* any value > 0: notfound, conflict */
#define DICT_STAT_SUCCESS   0   /* request satisfied */
#define DICT_STAT_ERROR     (-1)    /* any value < 0: database error */

 /*
  * Set an error code and return a result value.
  */
#define DICT_ERR_VAL_RETURN(dict, err, val) do { \
    (dict)->error = (err); \
    return (val); \
    } while (0)

 /*
  * Sequence function types.
  */
#define DICT_SEQ_FUN_FIRST     0    /* set cursor to first record */
#define DICT_SEQ_FUN_NEXT      1    /* set cursor to next record */

 /*
  * Interface for dictionary types.
  */
extern ARGV *dict_mapnames(void);
typedef void (*DICT_MAPNAMES_EXTEND_FN) (ARGV *);
extern DICT_MAPNAMES_EXTEND_FN dict_mapnames_extend(DICT_MAPNAMES_EXTEND_FN);


 /*
  * High-level interface, with logical dictionary names.
  */
extern void dict_register(const char *, DICT *);
extern DICT *dict_handle(const char *);
extern void dict_unregister(const char *);
extern int dict_update(const char *, const char *, const char *);
extern const char *dict_lookup(const char *, const char *);
extern int dict_delete(const char *, const char *);
extern int dict_sequence(const char *, const int, const char **, const char **);
extern int dict_load_file_xt(const char *, const char *);
extern void dict_load_fp(const char *, VSTREAM *);
extern const char *dict_eval(const char *, const char *, int);
extern int dict_error(const char *);

 /*
  * Low-level interface, with physical dictionary handles.
  */
typedef DICT *(*DICT_OPEN_FN) (const char *, int, int);
typedef DICT_OPEN_FN (*DICT_OPEN_EXTEND_FN) (const char *);
extern DICT *dict_open(const char *, int, int);
extern DICT *dict_open3(const char *, const char *, int, int);
extern void dict_open_register(const char *, DICT_OPEN_FN);
extern DICT_OPEN_EXTEND_FN dict_open_extend(DICT_OPEN_EXTEND_FN);

#define dict_get(dp, key)   ((const char *) (dp)->lookup((dp), (key)))
#define dict_put(dp, key, val)  (dp)->update((dp), (key), (val))
#define dict_del(dp, key)   (dp)->delete((dp), (key))
#define dict_seq(dp, f, key, val) (dp)->sequence((dp), (f), (key), (val))
#define dict_close(dp)      (dp)->close(dp)
typedef void (*DICT_WALK_ACTION) (const char *, DICT *, void *);
extern void dict_walk(DICT_WALK_ACTION, void *);
extern int dict_changed(void);
extern const char *dict_changed_name(void);
extern const char *dict_flags_str(int);
extern int dict_flags_mask(const char *);
extern void dict_type_override(DICT *, const char *);

 /*
  * Check and convert UTF-8 keys and values.
  */
typedef struct DICT_UTF8_BACKUP {
    const char *(*lookup) (struct DICT *, const char *);
    int     (*update) (struct DICT *, const char *, const char *);
    int     (*delete) (struct DICT *, const char *);
} DICT_UTF8_BACKUP;

extern DICT *dict_utf8_activate(DICT *);

 /*
  * Driver for interactive or scripted tests.
  */
void    dict_test(int, char **);

 /*
  * Behind-the-scenes support to continue execution with reduced
  * functionality.
  */
extern int dict_allow_surrogate;
extern DICT *PRINTFLIKE(5, 6) dict_surrogate(const char *, const char *, int, int, const char *,...);

 /*
  * This name is reserved for matchlist error handling.
  */
#define DICT_TYPE_NOFILE    "non-existent"
#define DICT_TYPE_NOUTF8    "non-UTF-8"

 /*
  * Duplicated from vstream(3). This should probably be abstracted out.
  * 
  * Exception handling. We use pointer to jmp_buf to avoid a lot of unused
  * baggage for streams that don't need this functionality.
  * 
  * XXX sigsetjmp()/siglongjmp() save and restore the signal mask which can
  * avoid surprises in code that manipulates signals, but unfortunately some
  * systems have bugs in their implementation.
  */
#ifdef NO_SIGSETJMP
#define dict_setjmp(dict)   setjmp((dict)->jbuf[0])
#define dict_longjmp(dict, val) longjmp((dict)->jbuf[0], (val))
#else
#define dict_setjmp(dict)   sigsetjmp((dict)->jbuf[0], 1)
#define dict_longjmp(dict, val) siglongjmp((dict)->jbuf[0], (val))
#endif
#define dict_isjmp(dict)    ((dict)->jbuf != 0)

 /*
  * Temporary API. If exception handling proves to be useful,
  * dict_jmp_alloc() should be integrated into dict_alloc().
  */
extern void dict_jmp_alloc(DICT *);

/* 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
/*--*/

#endif