dbz.c

gcc-2.95.3 Linux下最常用的C编译器

	} else
		(void) fclose(f);

	/* and let dbminit do the work */
	return(dbminit(name));
}

/*
 - dbminit - open a database, creating it (using defaults) if necessary
 *
 * We try to leave errno set plausibly, to the extent that underlying
 * functions permit this, since many people consult it if dbminit() fails.
 */
int 				/* 0 success, -1 failure */
dbminit(name)
char *name;
{
	register int i;
	register size_t s;
	register char *dirfname;
	register char *pagfname;

	if (pagf != NULL) {
		DEBUG(("dbminit: dbminit already called once\n"));
		errno = 0;
		return(-1);
	}

	/* open the .dir file */
	dirfname = enstring(name, dir);
	if (dirfname == NULL)
		return(-1);
	dirf = fopen(dirfname, "r+");
	if (dirf == NULL) {
		dirf = fopen(dirfname, "r");
		dirronly = 1;
	} else
		dirronly = 0;
	free(dirfname);
	if (dirf == NULL) {
		DEBUG(("dbminit: can't open .dir file\n"));
		return(-1);
	}

	/* open the .pag file */
	pagfname = enstring(name, pag);
	if (pagfname == NULL) {
		(void) fclose(dirf);
		return(-1);
	}
	pagf = fopen(pagfname, "r+b");
	if (pagf == NULL) {
		pagf = fopen(pagfname, "rb");
		if (pagf == NULL) {
			DEBUG(("dbminit: .pag open failed\n"));
			(void) fclose(dirf);
			free(pagfname);
			return(-1);
		}
		pagronly = 1;
	} else if (dirronly)
		pagronly = 1;
	else
		pagronly = 0;
#ifdef NOBUFFER
	/*
	 * B News does not do adequate locking on its database accesses.
	 * Why it doesn't get into trouble using dbm is a mystery.  In any
	 * case, doing unbuffered i/o does not cure the problem, but does
	 * enormously reduce its incidence.
	 */
	(void) setbuf(pagf, (char *)NULL);
#else
#ifdef _IOFBF
	(void) setvbuf(pagf, (char *)pagbuf, _IOFBF, sizeof(pagbuf));
#endif
#endif
	pagpos = -1;
	/* don't free pagfname, need it below */

	/* open the base file */
	basef = fopen(name, "r");
	if (basef == NULL) {
		DEBUG(("dbminit: basefile open failed\n"));
		basefname = enstring(name, "");
		if (basefname == NULL) {
			(void) fclose(pagf);
			(void) fclose(dirf);
			free(pagfname);
			pagf = NULL;
			return(-1);
		}
	} else
		basefname = NULL;
#ifdef _IOFBF
	if (basef != NULL)
		(void) setvbuf(basef, basebuf, _IOFBF, sizeof(basebuf));
#endif

	/* pick up configuration */
	if (getconf(dirf, pagf, &conf) < 0) {
		DEBUG(("dbminit: getconf failure\n"));
		(void) fclose(basef);
		(void) fclose(pagf);
		(void) fclose(dirf);
		free(pagfname);
		pagf = NULL;
		errno = EDOM;	/* kind of a kludge, but very portable */
		return(-1);
	}
	tagbits = conf.tagmask << conf.tagshift;
	taghere = conf.tagenb << conf.tagshift;
	tagboth = tagbits | taghere;
	mybytemap(mybmap);
	bytesame = 1;
	for (i = 0; i < SOF; i++)
		if (mybmap[i] != conf.bytemap[i])
			bytesame = 0;

	/* get first table into core, if it looks desirable and feasible */
	s = (size_t)conf.tsize * SOF;
	if (incore && (off_t)(s/SOF) == conf.tsize) {
		bufpagf = fopen(pagfname, (pagronly) ? "rb" : "r+b");
		if (bufpagf != NULL)
			corepag = getcore(bufpagf);
	} else {
		bufpagf = NULL;
		corepag = NULL;
	}
	free(pagfname);

	/* misc. setup */
	crcinit();
	written = 0;
	prevp = FRESH;
	DEBUG(("dbminit: succeeded\n"));
	return(0);
}

/*
 - enstring - concatenate two strings into a malloced area
 */
static char *			/* NULL if malloc fails */
enstring(s1, s2)
char *s1;
char *s2;
{
	register char *p;

	p = malloc((size_t)strlen(s1) + (size_t)strlen(s2) + 1);
	if (p != NULL) {
		(void) strcpy(p, s1);
		(void) strcat(p, s2);
	} else {
		DEBUG(("enstring(%s, %s) out of memory\n", s1, s2));
	}
	return(p);
}

/*
 - dbmclose - close a database
 */
int
dbmclose()
{
	register int ret = 0;

	if (pagf == NULL) {
		DEBUG(("dbmclose: not opened!\n"));
		return(-1);
	}

	if (fclose(pagf) == EOF) {
		DEBUG(("dbmclose: fclose(pagf) failed\n"));
		ret = -1;
	}
	pagf = basef;		/* ensure valid pointer; dbzsync checks it */
	if (dbzsync() < 0)
		ret = -1;
	if (bufpagf != NULL && fclose(bufpagf) == EOF) {
		DEBUG(("dbmclose: fclose(bufpagf) failed\n"));
		ret = -1;
	}
	if (corepag != NULL)
		free((char *)corepag);
	corepag = NULL;
	if (fclose(basef) == EOF) {
		DEBUG(("dbmclose: fclose(basef) failed\n"));
		ret = -1;
	}
	if (basefname != NULL)
		free(basefname);
	basef = NULL;
	pagf = NULL;
	if (fclose(dirf) == EOF) {
		DEBUG(("dbmclose: fclose(dirf) failed\n"));
		ret = -1;
	}

	DEBUG(("dbmclose: %s\n", (ret == 0) ? "succeeded" : "failed"));
	return(ret);
}

/*
 - dbzsync - push all in-core data out to disk
 */
int
dbzsync()
{
	register int ret = 0;

	if (pagf == NULL) {
		DEBUG(("dbzsync: not opened!\n"));
		return(-1);
	}
	if (!written)
		return(0);

	if (corepag != NULL) {
		if (putcore(corepag, bufpagf) < 0) {
			DEBUG(("dbzsync: putcore failed\n"));
			ret = -1;
		}
	}
	if (!conf.olddbz)
		if (putconf(dirf, &conf) < 0)
			ret = -1;

	DEBUG(("dbzsync: %s\n", (ret == 0) ? "succeeded" : "failed"));
	return(ret);
}

/*
 - dbzcancel - cancel writing of in-core data
 * Mostly for use from child processes.
 * Note that we don't need to futz around with stdio buffers, because we
 * always fflush them immediately anyway and so they never have stale data.
 */
int
dbzcancel()
{
	if (pagf == NULL) {
		DEBUG(("dbzcancel: not opened!\n"));
		return(-1);
	}

	written = 0;
	return(0);
}

/*
 - dbzfetch - fetch() with case mapping built in
 */
datum
dbzfetch(key)
datum key;
{
	char buffer[DBZMAXKEY + 1];
	datum mappedkey;
	register size_t keysize;

	DEBUG(("dbzfetch: (%s)\n", key.dptr));

	/* Key is supposed to be less than DBZMAXKEY */
	keysize = key.dsize;
	if (keysize >= DBZMAXKEY) {
		keysize = DBZMAXKEY;
		DEBUG(("keysize is %d - truncated to %d\n", key.dsize, DBZMAXKEY));
	}

	mappedkey.dptr = mapcase(buffer, key.dptr, keysize);
	buffer[keysize] = '\0';	/* just a debug aid */
	mappedkey.dsize = keysize;

	return(fetch(mappedkey));
}

/*
 - fetch - get an entry from the database
 *
 * Disgusting fine point, in the name of backward compatibility:  if the
 * last character of "key" is a NUL, that character is (effectively) not
 * part of the comparison against the stored keys.
 */
datum				/* dptr NULL, dsize 0 means failure */
fetch(key)
datum key;
{
	char buffer[DBZMAXKEY + 1];
	static off_t key_ptr;		/* return value points here */
	datum output;
	register size_t keysize;
	register size_t cmplen;
	register char *sepp;

	DEBUG(("fetch: (%s)\n", key.dptr));
	output.dptr = NULL;
	output.dsize = 0;
	prevp = FRESH;

	/* Key is supposed to be less than DBZMAXKEY */
	keysize = key.dsize;
	if (keysize >= DBZMAXKEY) {
		keysize = DBZMAXKEY;
		DEBUG(("keysize is %d - truncated to %d\n", key.dsize, DBZMAXKEY));
	}

	if (pagf == NULL) {
		DEBUG(("fetch: database not open!\n"));
		return(output);
	} else if (basef == NULL) {	/* basef didn't exist yet */
		basef = latebase();
		if (basef == NULL)
			return(output);
	}

	cmplen = keysize;
	sepp = &conf.fieldsep;
	if (key.dptr[keysize-1] == '\0') {
		cmplen--;
		sepp = &buffer[keysize-1];
	}
	start(&srch, &key, FRESH);
	while ((key_ptr = search(&srch)) != NOTFOUND) {
		DEBUG(("got 0x%lx\n", key_ptr));

		/* fetch the key */
		if (fseek(basef, key_ptr, SEEK_SET) != 0) {
			DEBUG(("fetch: seek failed\n"));
			return(output);
		}
		if (fread(buffer, 1, keysize, basef) != keysize) {
			DEBUG(("fetch: read failed\n"));
			return(output);
		}

		/* try it */
		buffer[keysize] = '\0';		/* terminated for DEBUG */
		(void) mapcase(buffer, buffer, keysize);
		DEBUG(("fetch: buffer (%s) looking for (%s) size = %d\n", 
						buffer, key.dptr, keysize));
		if (memcmp(key.dptr, buffer, cmplen) == 0 &&
				(*sepp == conf.fieldsep || *sepp == '\0')) {
			/* we found it */
			output.dptr = (char *)&key_ptr;
			output.dsize = SOF;
			DEBUG(("fetch: successful\n"));
			return(output);
		}
	}

	/* we didn't find it */
	DEBUG(("fetch: failed\n"));
	prevp = &srch;			/* remember where we stopped */
	return(output);
}

/*
 - latebase - try to open a base file that wasn't there at the start
 */
static FILE *
latebase()
{
	register FILE *it;

	if (basefname == NULL) {
		DEBUG(("latebase: name foulup\n"));
		return(NULL);
	}
	it = fopen(basefname, "r");
	if (it == NULL) {
		DEBUG(("latebase: still can't open base\n"));
	} else {
		DEBUG(("latebase: late open succeeded\n"));
		free(basefname);
		basefname = NULL;
#ifdef _IOFBF
		(void) setvbuf(it, basebuf, _IOFBF, sizeof(basebuf));
#endif
	}
	return(it);
}

/*
 - dbzstore - store() with case mapping built in
 */
int
dbzstore(key, data)
datum key;
datum data;
{
	char buffer[DBZMAXKEY + 1];
	datum mappedkey;
	register size_t keysize;

	DEBUG(("dbzstore: (%s)\n", key.dptr));

	/* Key is supposed to be less than DBZMAXKEY */
	keysize = key.dsize;
	if (keysize >= DBZMAXKEY) {
		DEBUG(("dbzstore: key size too big (%d)\n", key.dsize));
		return(-1);
	}

	mappedkey.dptr = mapcase(buffer, key.dptr, keysize);
	buffer[keysize] = '\0';	/* just a debug aid */
	mappedkey.dsize = keysize;

	return(store(mappedkey, data));
}

/*
 - store - add an entry to the database
 */
int				/* 0 success, -1 failure */
store(key, data)
datum key;
datum data;
{
	off_t value;

	if (pagf == NULL) {
		DEBUG(("store: database not open!\n"));
		return(-1);
	} else if (basef == NULL) {	/* basef didn't exist yet */
		basef = latebase();
		if (basef == NULL)
			return(-1);
	}
	if (pagronly) {
		DEBUG(("store: database open read-only\n"));
		return(-1);
	}
	if (data.dsize != SOF) {
		DEBUG(("store: value size wrong (%d)\n", data.dsize));
		return(-1);
	}
	if (key.dsize >= DBZMAXKEY) {
		DEBUG(("store: key size too big (%d)\n", key.dsize));
		return(-1);
	}

	/* copy the value in to ensure alignment */
	(void) memcpy((char *)&value, data.dptr, SOF);
	DEBUG(("store: (%s, %ld)\n", key.dptr, (long)value));
	if (!okayvalue(value)) {
		DEBUG(("store: reserved bit or overflow in 0x%lx\n", value));
		return(-1);
	}

	/* find the place, exploiting previous search if possible */
	start(&srch, &key, prevp);
	while (search(&srch) != NOTFOUND)
		continue;

	prevp = FRESH;
	conf.used[0]++;
	DEBUG(("store: used count %ld\n", conf.used[0]));
	written = 1;
	return(set(&srch, value));
}

/*
 - dbzincore - control attempts to keep .pag file in core
 */
int				/* old setting */
dbzincore(value)
int value;
{
	register int old = incore;

	incore = value;
	return(old);
}

/*
 - getconf - get configuration from .dir file
 */
static int			/* 0 success, -1 failure */
getconf(df, pf, cp)
register FILE *df;		/* NULL means just give me the default */
register FILE *pf;		/* NULL means don't care about .pag */
register struct dbzconfig *cp;
{
	register int c;
	register int i;
	int err = 0;

	c = (df != NULL) ? getc(df) : EOF;
	if (c == EOF) {		/* empty file, no configuration known */
		cp->olddbz = 0;
		if (df != NULL && pf != NULL && getc(pf) != EOF)
			cp->olddbz = 1;
		cp->tsize = DEFSIZE;
		cp->fieldsep = '\t';
		for (i = 0; i < NUSEDS; i++)
			cp->used[i] = 0;
		cp->valuesize = SOF;
		mybytemap(cp->bytemap);
		cp->casemap = DEFCASE;
		cp->tagenb = TAGENB;
		cp->tagmask = TAGMASK;
		cp->tagshift = TAGSHIFT;
		DEBUG(("getconf: defaults (%ld, %c, (0x%lx/0x%lx<<%d))\n",
			cp->tsize, cp->casemap, cp->tagenb, 
			cp->tagmask, cp->tagshift));
		return(0);
	}
	(void) ungetc(c, df);

	/* first line, the vital stuff */
	if (getc(df) != 'd' || getc(df) != 'b' || getc(df) != 'z')
		err = -1;
	if (getno(df, &err) != dbzversion)
		err = -1;
	cp->tsize = getno(df, &err);
	cp->fieldsep = getno(df, &err);
	while ((c = getc(df)) == ' ')
		continue;
	cp->casemap = c;
	cp->tagenb = getno(df, &err);
	cp->tagmask = getno(df, &err);
	cp->tagshift = getno(df, &err);
	cp->valuesize = getno(df, &err);
	if (cp->valuesize != SOF) {
		DEBUG(("getconf: wrong off_t size (%d)\n", cp->valuesize));
		err = -1;
		cp->valuesize = SOF;	/* to protect the loops below */
	}
	for (i = 0; i < cp->valuesize; i++)
		cp->bytemap[i] = getno(df, &err);
	if (getc(df) != '\n')
		err = -1;
	DEBUG(("size %ld, sep %d, cmap %c, tags 0x%lx/0x%lx<<%d, ", cp->tsize,
			cp->fieldsep, cp->casemap, cp->tagenb, cp->tagmask,
			cp->tagshift));
	DEBUG(("bytemap (%d)", cp->valuesize));
	for (i = 0; i < cp->valuesize; i++) {
		DEBUG((" %d", cp->bytemap[i]));
	}
	DEBUG(("\n"));

	/* second line, the usages */
	for (i = 0; i < NUSEDS; i++)
		cp->used[i] = getno(df, &err);
	if (getc(df) != '\n')
		err = -1;
	DEBUG(("used %ld %ld %ld...\n", cp->used[0], cp->used[1], cp->used[2]));

	if (err < 0) {
		DEBUG(("getconf error\n"));
		return(-1);
	}
	return(0);
}

/*
 - getno - get a long
 */
static long
getno(f, ep)
FILE *f;
int *ep;
{
	register char *p;
#	define	MAXN	50
	char getbuf[MAXN];
	register int c;

	while ((c = getc(f)) == ' ')
		continue;
	if (c == EOF || c == '\n') {
		DEBUG(("getno: missing number\n"));
		*ep = -1;
		return(0);
	}
	p = getbuf;
	*p++ = c;
	while ((c = getc(f)) != EOF && c != '\n' && c != ' ')
		if (p < &getbuf[MAXN-1])
			*p++ = c;
	if (c == EOF) {
		DEBUG(("getno: EOF\n"));
		*ep = -1;
	} else
		(void) ungetc(c, f);
	*p = '\0';

	if (strspn(getbuf, "-1234567890") != strlen(getbuf)) {
		DEBUG(("getno: `%s' non-numeric\n", getbuf));