| Current File : //root/postfix-3.2.0/src/util/dict_cdb.c |
/*++
/* NAME
/* dict_cdb 3
/* SUMMARY
/* dictionary manager interface to CDB files
/* SYNOPSIS
/* #include <dict_cdb.h>
/*
/* DICT *dict_cdb_open(path, open_flags, dict_flags)
/* const char *path;
/* int open_flags;
/* int dict_flags;
/*
/* DESCRIPTION
/* dict_cdb_open() opens the specified CDB database. The result is
/* a pointer to a structure that can be used to access the dictionary
/* using the generic methods documented in dict_open(3).
/*
/* Arguments:
/* .IP path
/* The database pathname, not including the ".cdb" suffix.
/* .IP open_flags
/* Flags passed to open(). Specify O_RDONLY or O_WRONLY|O_CREAT|O_TRUNC.
/* .IP dict_flags
/* Flags used by the dictionary interface.
/* SEE ALSO
/* dict(3) generic dictionary manager
/* DIAGNOSTICS
/* Fatal errors: cannot open file, write error, out of memory.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Michael Tokarev <mjt@tls.msk.ru> based on dict_db.c by
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*--*/
#include "sys_defs.h"
/* System library. */
#include <sys/stat.h>
#include <limits.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
/* Utility library. */
#include "msg.h"
#include "mymalloc.h"
#include "vstring.h"
#include "stringops.h"
#include "iostuff.h"
#include "myflock.h"
#include "stringops.h"
#include "dict.h"
#include "dict_cdb.h"
#include "warn_stat.h"
#ifdef HAS_CDB
#include <cdb.h>
#ifndef TINYCDB_VERSION
#include <cdb_make.h>
#endif
#ifndef cdb_fileno
#define cdb_fileno(c) ((c)->fd)
#endif
#ifndef CDB_SUFFIX
#define CDB_SUFFIX ".cdb"
#endif
#ifndef CDB_TMP_SUFFIX
#define CDB_TMP_SUFFIX CDB_SUFFIX ".tmp"
#endif
/* Application-specific. */
typedef struct {
DICT dict; /* generic members */
struct cdb cdb; /* cdb structure */
} DICT_CDBQ; /* query interface */
typedef struct {
DICT dict; /* generic members */
struct cdb_make cdbm; /* cdb_make structure */
char *cdb_path; /* cdb pathname (.cdb) */
char *tmp_path; /* temporary pathname (.tmp) */
} DICT_CDBM; /* rebuild interface */
/* dict_cdbq_lookup - find database entry, query mode */
static const char *dict_cdbq_lookup(DICT *dict, const char *name)
{
DICT_CDBQ *dict_cdbq = (DICT_CDBQ *) dict;
unsigned vlen;
int status = 0;
static char *buf;
static unsigned len;
const char *result = 0;
dict->error = 0;
/* CDB is constant, so do not try to acquire a lock. */
/*
* Optionally fold the key.
*/
if (dict->flags & DICT_FLAG_FOLD_FIX) {
if (dict->fold_buf == 0)
dict->fold_buf = vstring_alloc(10);
vstring_strcpy(dict->fold_buf, name);
name = lowercase(vstring_str(dict->fold_buf));
}
/*
* See if this CDB file was written with one null byte appended to key
* and value.
*/
if (dict->flags & DICT_FLAG_TRY1NULL) {
status = cdb_find(&dict_cdbq->cdb, name, strlen(name) + 1);
if (status > 0)
dict->flags &= ~DICT_FLAG_TRY0NULL;
}
/*
* See if this CDB file was written with no null byte appended to key and
* value.
*/
if (status == 0 && (dict->flags & DICT_FLAG_TRY0NULL)) {
status = cdb_find(&dict_cdbq->cdb, name, strlen(name));
if (status > 0)
dict->flags &= ~DICT_FLAG_TRY1NULL;
}
if (status < 0)
msg_fatal("error reading %s: %m", dict->name);
if (status) {
vlen = cdb_datalen(&dict_cdbq->cdb);
if (len < vlen) {
if (buf == 0)
buf = mymalloc(vlen + 1);
else
buf = myrealloc(buf, vlen + 1);
len = vlen;
}
if (cdb_read(&dict_cdbq->cdb, buf, vlen,
cdb_datapos(&dict_cdbq->cdb)) < 0)
msg_fatal("error reading %s: %m", dict->name);
buf[vlen] = '\0';
result = buf;
}
/* No locking so not release the lock. */
return (result);
}
/* dict_cdbq_close - close data base, query mode */
static void dict_cdbq_close(DICT *dict)
{
DICT_CDBQ *dict_cdbq = (DICT_CDBQ *) dict;
cdb_free(&dict_cdbq->cdb);
close(dict->stat_fd);
if (dict->fold_buf)
vstring_free(dict->fold_buf);
dict_free(dict);
}
/* dict_cdbq_open - open data base, query mode */
static DICT *dict_cdbq_open(const char *path, int dict_flags)
{
DICT_CDBQ *dict_cdbq;
struct stat st;
char *cdb_path;
int fd;
/*
* Let the optimizer worry about eliminating redundant code.
*/
#define DICT_CDBQ_OPEN_RETURN(d) do { \
DICT *__d = (d); \
myfree(cdb_path); \
return (__d); \
} while (0)
cdb_path = concatenate(path, CDB_SUFFIX, (char *) 0);
if ((fd = open(cdb_path, O_RDONLY)) < 0)
DICT_CDBQ_OPEN_RETURN(dict_surrogate(DICT_TYPE_CDB, path,
O_RDONLY, dict_flags,
"open database %s: %m", cdb_path));
dict_cdbq = (DICT_CDBQ *) dict_alloc(DICT_TYPE_CDB,
cdb_path, sizeof(*dict_cdbq));
#if defined(TINYCDB_VERSION)
if (cdb_init(&(dict_cdbq->cdb), fd) != 0)
msg_fatal("dict_cdbq_open: unable to init %s: %m", cdb_path);
#else
cdb_init(&(dict_cdbq->cdb), fd);
#endif
dict_cdbq->dict.lookup = dict_cdbq_lookup;
dict_cdbq->dict.close = dict_cdbq_close;
dict_cdbq->dict.stat_fd = fd;
if (fstat(fd, &st) < 0)
msg_fatal("dict_dbq_open: fstat: %m");
dict_cdbq->dict.mtime = st.st_mtime;
dict_cdbq->dict.owner.uid = st.st_uid;
dict_cdbq->dict.owner.status = (st.st_uid != 0);
close_on_exec(fd, CLOSE_ON_EXEC);
/*
* Warn if the source file is newer than the indexed file, except when
* the source file changed only seconds ago.
*/
if (stat(path, &st) == 0
&& st.st_mtime > dict_cdbq->dict.mtime
&& st.st_mtime < time((time_t *) 0) - 100)
msg_warn("database %s is older than source file %s", cdb_path, path);
/*
* If undecided about appending a null byte to key and value, choose to
* try both in query mode.
*/
if ((dict_flags & (DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL)) == 0)
dict_flags |= DICT_FLAG_TRY0NULL | DICT_FLAG_TRY1NULL;
dict_cdbq->dict.flags = dict_flags | DICT_FLAG_FIXED;
if (dict_flags & DICT_FLAG_FOLD_FIX)
dict_cdbq->dict.fold_buf = vstring_alloc(10);
DICT_CDBQ_OPEN_RETURN(DICT_DEBUG (&dict_cdbq->dict));
}
/* dict_cdbm_update - add database entry, create mode */
static int dict_cdbm_update(DICT *dict, const char *name, const char *value)
{
DICT_CDBM *dict_cdbm = (DICT_CDBM *) dict;
unsigned ksize, vsize;
int r;
dict->error = 0;
/*
* Optionally fold the key.
*/
if (dict->flags & DICT_FLAG_FOLD_FIX) {
if (dict->fold_buf == 0)
dict->fold_buf = vstring_alloc(10);
vstring_strcpy(dict->fold_buf, name);
name = lowercase(vstring_str(dict->fold_buf));
}
ksize = strlen(name);
vsize = strlen(value);
/*
* Optionally append a null byte to key and value.
*/
if (dict->flags & DICT_FLAG_TRY1NULL) {
ksize++;
vsize++;
}
/*
* Do the add operation. No locking is done.
*/
#ifdef TINYCDB_VERSION
#ifndef CDB_PUT_ADD
#error please upgrate tinycdb to at least 0.5 version
#endif
if (dict->flags & DICT_FLAG_DUP_IGNORE)
r = CDB_PUT_ADD;
else if (dict->flags & DICT_FLAG_DUP_REPLACE)
r = CDB_PUT_REPLACE;
else
r = CDB_PUT_INSERT;
r = cdb_make_put(&dict_cdbm->cdbm, name, ksize, value, vsize, r);
if (r < 0)
msg_fatal("error writing %s: %m", dict_cdbm->tmp_path);
else if (r > 0) {
if (dict->flags & (DICT_FLAG_DUP_IGNORE | DICT_FLAG_DUP_REPLACE))
/* void */ ;
else if (dict->flags & DICT_FLAG_DUP_WARN)
msg_warn("%s: duplicate entry: \"%s\"",
dict_cdbm->dict.name, name);
else
msg_fatal("%s: duplicate entry: \"%s\"",
dict_cdbm->dict.name, name);
}
return (r);
#else
if (cdb_make_add(&dict_cdbm->cdbm, name, ksize, value, vsize) < 0)
msg_fatal("error writing %s: %m", dict_cdbm->tmp_path);
return (0);
#endif
}
/* dict_cdbm_close - close data base and rename file.tmp to file.cdb */
static void dict_cdbm_close(DICT *dict)
{
DICT_CDBM *dict_cdbm = (DICT_CDBM *) dict;
int fd = cdb_fileno(&dict_cdbm->cdbm);
/*
* Note: if FCNTL locking is used, closing any file descriptor on a
* locked file cancels all locks that the process may have on that file.
* CDB is FCNTL locking safe, because it uses the same file descriptor
* for database I/O and locking.
*/
if (cdb_make_finish(&dict_cdbm->cdbm) < 0)
msg_fatal("finish database %s: %m", dict_cdbm->tmp_path);
if (rename(dict_cdbm->tmp_path, dict_cdbm->cdb_path) < 0)
msg_fatal("rename database from %s to %s: %m",
dict_cdbm->tmp_path, dict_cdbm->cdb_path);
if (close(fd) < 0) /* releases a lock */
msg_fatal("close database %s: %m", dict_cdbm->cdb_path);
myfree(dict_cdbm->cdb_path);
myfree(dict_cdbm->tmp_path);
if (dict->fold_buf)
vstring_free(dict->fold_buf);
dict_free(dict);
}
/* dict_cdbm_open - create database as file.tmp */
static DICT *dict_cdbm_open(const char *path, int dict_flags)
{
DICT_CDBM *dict_cdbm;
char *cdb_path;
char *tmp_path;
int fd;
struct stat st0, st1;
/*
* Let the optimizer worry about eliminating redundant code.
*/
#define DICT_CDBM_OPEN_RETURN(d) do { \
DICT *__d = (d); \
if (cdb_path) \
myfree(cdb_path); \
if (tmp_path) \
myfree(tmp_path); \
return (__d); \
} while (0)
cdb_path = concatenate(path, CDB_SUFFIX, (char *) 0);
tmp_path = concatenate(path, CDB_TMP_SUFFIX, (char *) 0);
/*
* Repeat until we have opened *and* locked *existing* file. Since the
* new (tmp) file will be renamed to be .cdb file, locking here is
* somewhat funny to work around possible race conditions. Note that we
* can't open a file with O_TRUNC as we can't know if another process
* isn't creating it at the same time.
*/
for (;;) {
if ((fd = open(tmp_path, O_RDWR | O_CREAT, 0644)) < 0)
DICT_CDBM_OPEN_RETURN(dict_surrogate(DICT_TYPE_CDB, path,
O_RDWR, dict_flags,
"open database %s: %m",
tmp_path));
if (fstat(fd, &st0) < 0)
msg_fatal("fstat(%s): %m", tmp_path);
/*
* Get an exclusive lock - we're going to change the database so we
* can't have any spectators.
*/
if (myflock(fd, INTERNAL_LOCK, MYFLOCK_OP_EXCLUSIVE) < 0)
msg_fatal("lock %s: %m", tmp_path);
if (stat(tmp_path, &st1) < 0)
msg_fatal("stat(%s): %m", tmp_path);
/*
* Compare file's state before and after lock: should be the same,
* and nlinks should be >0, or else we opened non-existing file...
*/
if (st0.st_ino == st1.st_ino && st0.st_dev == st1.st_dev
&& st0.st_rdev == st1.st_rdev && st0.st_nlink == st1.st_nlink
&& st0.st_nlink > 0)
break; /* successefully opened */
close(fd);
}
#ifndef NO_FTRUNCATE
if (st0.st_size)
ftruncate(fd, 0);
#endif
dict_cdbm = (DICT_CDBM *) dict_alloc(DICT_TYPE_CDB, path,
sizeof(*dict_cdbm));
if (cdb_make_start(&dict_cdbm->cdbm, fd) < 0)
msg_fatal("initialize database %s: %m", tmp_path);
dict_cdbm->dict.close = dict_cdbm_close;
dict_cdbm->dict.update = dict_cdbm_update;
dict_cdbm->cdb_path = cdb_path;
dict_cdbm->tmp_path = tmp_path;
cdb_path = tmp_path = 0; /* DICT_CDBM_OPEN_RETURN() */
dict_cdbm->dict.owner.uid = st1.st_uid;
dict_cdbm->dict.owner.status = (st1.st_uid != 0);
close_on_exec(fd, CLOSE_ON_EXEC);
/*
* If undecided about appending a null byte to key and value, choose a
* default to not append a null byte when creating a cdb.
*/
if ((dict_flags & (DICT_FLAG_TRY1NULL | DICT_FLAG_TRY0NULL)) == 0)
dict_flags |= DICT_FLAG_TRY0NULL;
else if ((dict_flags & DICT_FLAG_TRY1NULL)
&& (dict_flags & DICT_FLAG_TRY0NULL))
dict_flags &= ~DICT_FLAG_TRY0NULL;
dict_cdbm->dict.flags = dict_flags | DICT_FLAG_FIXED;
if (dict_flags & DICT_FLAG_FOLD_FIX)
dict_cdbm->dict.fold_buf = vstring_alloc(10);
DICT_CDBM_OPEN_RETURN(DICT_DEBUG (&dict_cdbm->dict));
}
/* dict_cdb_open - open data base for query mode or create mode */
DICT *dict_cdb_open(const char *path, int open_flags, int dict_flags)
{
switch (open_flags & (O_RDONLY | O_RDWR | O_WRONLY | O_CREAT | O_TRUNC)) {
case O_RDONLY: /* query mode */
return dict_cdbq_open(path, dict_flags);
case O_WRONLY | O_CREAT | O_TRUNC: /* create mode */
case O_RDWR | O_CREAT | O_TRUNC: /* sloppiness */
return dict_cdbm_open(path, dict_flags);
default:
msg_fatal("dict_cdb_open: inappropriate open flags for cdb database"
" - specify O_RDONLY or O_WRONLY|O_CREAT|O_TRUNC");
}
}
#endif /* HAS_CDB */