* support extra two arguments to nsdispatch():

const char *method		/* method name for dynamic linking */
	const ns_src defaults[]		/* list of defaults */
* document above, and expand other docco.

lib/libc/net/nsdispatch.3

@@ -1,4 +1,4 @@
-.\"	$NetBSD: nsdispatch.3,v 1.3 1999/01/16 07:55:43 lukem Exp $
+.\"	$NetBSD: nsdispatch.3,v 1.4 1999/01/19 07:58:05 lukem Exp $
 .\"
 .\" Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -34,7 +34,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd January 16, 1999
+.Dd January 19, 1999
 .Dt NSDISPATCH 3
 .Os NetBSD
 .Sh NAME
@@ -43,7 +43,14 @@
 .Sh SYNOPSIS
 .Fd #include <nsswitch.h>
 .Ft int
-.Fn nsdispatch "void *retval" "const ns_dtab dtab[]" "const char *database" "..."
+.Fo nsdispatch
+.Fa "void *retval"
+.Fa "const ns_dtab dtab[]"
+.Fa "const char *database"
+.Fa "const char *method"
+.Fa "const ns_src defaults[]"
+.Fa "..."
+.Fc
 .Sh DESCRIPTION
 The
 .Fn nsdispatch
@@ -55,28 +62,25 @@ for the database
 .Va database
 until a successful entry is found.
 .Pp
-The return value from the last function invoked is stored at
+.Va retval
-the location specified in
+is passed to each callback function to modify as necessary
-.Va retval .
+(to pass back to the caller of
+.Fn nsdispatch )
 .Pp
-The optional extra arguments given in
+.Va dtab
-.Va ...
+is an array of
-are passed to the appropriate callback function as a variable argument
-list of the type
-.Va va_list .
-.Pp
-The format of the
 .Va ns_dtab
-structure is as follows:
+structures, which have the following format:
 .Bd -literal -offset indent
 typedef struct {
 	const char *src;
 	int (*cb)(void *retval, void *cb_data, va_list ap);
 	void *cb_data;
-} ns_dtab [];
+} ns_dtab;
 .Ed
 .Pp
-For each source type that is implemented, and entry with
+.Bd -ragged -offset indent
+For each source type that is implemented, an entry with
 .Va src
 set to the name of the source,
 .Va cb
@@ -92,15 +96,74 @@ values for
 .Va cb ,
 and
 .Va cb_data .
+.Ed
+.Pp
+.Va method
+is usually the name of the function calling
+.Fn nsdispatch .
+When dynamic loading is supported, a symbol constructed from
+.Va database ,
+the current source, and
+.Va method
+will be used as the name to invoke the dynamically loaded function.
+.Pp
+.Va defaults
+contains a list of default sources to try in the case of
+a missing or absent
+.Xr nsswitch.conf 5 ,
+or if there isn't a relevant entry for
+.Va database .
+It is an array of
+.Va ns_src
+structures, which have the following format:
+.Bd -literal -offset indent
+typedef struct {
+	const char *src;
+	u_int32_t flags;
+} ns_src;
+.Ed
+.Pp
+.Bd -ragged -offset indent
+For each default source type, an entry with
+.Va src
+set to the name of the source, and
+.Va flags
+set to the relevant flags
+(usually 
+.Dv NS_SUCCESS ;
+refer to
+.Sx Callback return values
+for more information).
+The last entry in
+.Va defaults
+should have
+.Va src
+set to
+.Dv NULL
+and
+.Va flags
+set to 0.
+.Pp
+For convenience, a global variable defined as:
+.Dl extern const ns_src __nsdefaultsrc[];
+exists which contains a single default entry for
+.Sq files
+for use by callers which don't require complicated default rules.
+.Ed
+.Pp
+.Va Sq ...
+are optional extra arguments, which
+are passed to the appropriate callback function as a variable argument
+list of the type
+.Va va_list .
 .Ss Valid source types
 Whilst there is support for arbitrary sources, the following
 #defines for commonly implementated sources are available:
-.Bl -column NS_NISPLUS NISPLUS -offset indent
+.Bl -column NS_COMPAT COMPAT -offset indent
 .Sy #define	value
 .It NSSRC_FILES	"files"
 .It NSSRC_DNS	"dns"
 .It NSSRC_NIS	"nis"
-.It NSSRC_NISPLUS	"nisplus"
 .It NSSRC_COMPAT	"compat"
 .El
 .Pp

lib/libc/net/nsdispatch.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: nsdispatch.c,v 1.4 1999/01/17 04:49:04 lukem Exp $	*/
+/*	$NetBSD: nsdispatch.c,v 1.5 1999/01/19 07:58:05 lukem Exp $	*/
 
 /*-
  * Copyright (c) 1997, 1998, 1999 The NetBSD Foundation, Inc.
@@ -50,6 +50,15 @@
 #include <unistd.h>
 
 
+/*
+ * default sourcelist: `files'
+ */
+const ns_src __nsdefaultsrc[] = {
+	{ NSSRC_FILES, NS_SUCCESS },
+	{ 0 },
+};
+
+
 static	int			 _nsmapsize = 0;
 static	ns_dbt			*_nsmap = NULL;
 
@@ -121,26 +130,18 @@ _nsdbtget(name)
 	const char	*name;
 {
 	static	time_t	 confmod;
-	static	ns_dbt	 dbt;
 
 	struct stat	 statbuf;
-	ns_dbt		*ndbt;
+	ns_dbt		 dbt;
 
 	extern	FILE 	*_nsyyin;
 	extern	int	 _nsyyparse __P((void));
 
-	if (dbt.srclist == NULL) {	/* construct dummy `files' entry */
-		ns_src	src;
-
-		src.name = NSSRC_FILES;
-		src.flags = NS_SUCCESS;
-		_nsdbtaddsrc(&dbt, &src);
-	}
 	dbt.name = name;
 
 	if (confmod) {
 		if (stat(_PATH_NS_CONF, &statbuf) == -1)
-			return (&dbt);
+			return (NULL);
 		if (confmod < statbuf.st_mtime) {
 			int i, j;
 
@@ -164,19 +165,16 @@ _nsdbtget(name)
 	}
 	if (!confmod) {
 		if (stat(_PATH_NS_CONF, &statbuf) == -1)
-			return (&dbt);
+			return (NULL);
 		_nsyyin = fopen(_PATH_NS_CONF, "r");
 		if (_nsyyin == NULL)
-			return (&dbt);
+			return (NULL);
 		_nsyyparse();
 		(void)fclose(_nsyyin);
 		qsort(_nsmap, _nsmapsize, sizeof(ns_dbt), _nscmp);
 		confmod = statbuf.st_mtime;
 	}
-	ndbt = bsearch(&dbt, _nsmap, _nsmapsize, sizeof(ns_dbt), _nscmp);
+	return (bsearch(&dbt, _nsmap, _nsmapsize, sizeof(ns_dbt), _nscmp));
-	if (ndbt != NULL)
-		return (ndbt);
-	return (&dbt);
 }
 
 
@@ -209,58 +207,55 @@ _nsdbtput(dbt)
 
 int
 #if __STDC__
-nsdispatch(void *retval, const ns_dtab disp_tab[], const char *database, ...)
+nsdispatch(void *retval, const ns_dtab disp_tab[], const char *database,
+	    const char *method, const ns_src defaults[], ...)
 #else
-nsdispatch(retval, disp_tab, database, va_alist)
+nsdispatch(retval, disp_tab, database, method, defaults, va_alist)
 	void		*retval;
 	const ns_dtab	 disp_tab[];
 	const char	*database;
+	const char	*method;
+	const ns_src	 defaults[];
 	va_dcl
 #endif
 {
 	va_list		 ap;
 	int		 i, curdisp, result;
 	const ns_dbt	*dbt;
+	const ns_src	*srclist;
+	int		 srclistsize;
 
 	dbt = _nsdbtget(database);
+	if (dbt != NULL) {
+		srclist = dbt->srclist;
+		srclistsize = dbt->srclistsize;
+	} else {
+		srclist = defaults;
+		srclistsize = 0;
+		while (srclist[srclistsize].name != NULL)
+			srclistsize++;
+	}
 	result = 0;
 
-#if _NS_DEBUG
+	for (i = 0; i < srclistsize; i++) {
-	_nsdumpdbt(dbt);
-	fprintf(stderr, "nsdispatch: %s\n", database);
-#endif
-	for (i = 0; i < dbt->srclistsize; i++) {
-#if _NS_DEBUG
-		fprintf(stderr, "    source=%s", dbt->srclist[i]->source);
-#endif
 		for (curdisp = 0; disp_tab[curdisp].src != NULL; curdisp++)
 			if (strcasecmp(disp_tab[curdisp].src,
-			    dbt->srclist[i].name) == 0)
+			    srclist[i].name) == 0)
 				break;
 		result = 0;
 		if (disp_tab[curdisp].callback) {
 #if __STDC__
-			va_start(ap, database);
+			va_start(ap, defaults);
 #else
 			va_start(ap);
 #endif
 			result = disp_tab[curdisp].callback(retval,
 			    disp_tab[curdisp].cb_data, ap);
 			va_end(ap);
-#if _NS_DEBUG
+			if (result & srclist[i].flags) {
-			fprintf(stderr, " result=%d (%d)", result,
-			    (result & dbt->srclist[i].flags));
-#endif
-			if (result & dbt->srclist[i].flags) {
-#if _NS_DEBUG
-				fprintf(stderr, " MATCH!\n");
-#endif
 				break;
 			}
 		}
-#if _NS_DEBUG
-		fprintf(stderr, "\n");
-#endif
 	}
 	return (result ? result : NS_NOTFOUND);
 }