Commit sid<->[ug]id extensions to libnss_winbind.so on Linux, as well as a

factored-out nss_winbind.[ch]. I took tridge's public domain license comment
for the nss_winbind.[ch].

This is probably not the last word on that extension, but as it is quite
non-intrusive to the main samba code, I would like to give it a start.

Volker
(This used to be commit da5944129fad39010544b82649dfe5531a504ecf)

4 files changed, 659 insertions, 266 deletions

diff --git a/examples/nss/nss_winbind.c b/examples/nss/nss_winbind.c
new file mode 100644
index 0000000000..968cc7addd
--- /dev/null
+++ b/examples/nss/nss_winbind.c
@@ -0,0 +1,422 @@
+/* 
+   nss sample code for extended winbindd functionality
+
+   Copyright (C) Andrew Tridgell (tridge@samba.org)   
+
+   you are free to use this code in any way you see fit, including
+   without restriction, using this code in your own products. You do
+   not need to give any attribution.
+*/
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <nss.h>
+#include <dlfcn.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/types.h>
+
+#include "nss_winbind.h"
+
+/*
+  find a function in the nss library
+*/
+static void *find_fn(struct nss_state *nss, const char *name)
+{
+	void *res;
+	char *s = NULL;
+
+	asprintf(&s, "_nss_%s_%s", nss->nss_name, name);
+	if (!s) {
+		errno = ENOMEM;
+		return NULL;
+	}
+	res = dlsym(nss->dl_handle, s);
+	free(s);
+	if (!res) {
+		errno = ENOENT;
+		return NULL;
+	}
+	return res;
+}
+
+/*
+  establish a link to the nss library
+  Return 0 on success and -1 on error
+*/
+int nss_open(struct nss_state *nss, const char *nss_path)
+{
+	char *p;
+	p = strrchr(nss_path, '_');
+	if (!p) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	nss->nss_name = strdup(p+1);
+	p = strchr(nss->nss_name, '.');
+	if (p) *p = 0;
+
+	nss->dl_handle = dlopen(nss_path, RTLD_LAZY);
+	if (!nss->dl_handle) {
+		free(nss->nss_name);
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+  close and cleanup a nss state
+*/
+void nss_close(struct nss_state *nss)
+{
+	free(nss->nss_name);
+	dlclose(nss->dl_handle);
+}
+
+/*
+  make a getpwnam call. 
+  Return 0 on success and -1 on error
+*/
+int nss_getpwent(struct nss_state *nss, struct passwd *pwd)
+{
+	enum nss_status (*_nss_getpwent_r)(struct passwd *, char *, 
+					   size_t , int *);
+	enum nss_status status;
+	int nss_errno = 0;
+
+	_nss_getpwent_r = find_fn(nss, "getpwent_r");
+
+	if (!_nss_getpwent_r) {
+		return -1;
+	}
+
+	status = _nss_getpwent_r(pwd, nss->pwnam_buf, sizeof(nss->pwnam_buf),
+				 &nss_errno);
+	if (status == NSS_STATUS_NOTFOUND) {
+		errno = ENOENT;
+		return -1;
+	}
+	if (status != NSS_STATUS_SUCCESS) {
+		errno = nss_errno;
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+  make a setpwent call. 
+  Return 0 on success and -1 on error
+*/
+int nss_setpwent(struct nss_state *nss)
+{
+	enum nss_status (*_nss_setpwent)(void) = find_fn(nss, "setpwent");
+	enum nss_status status;
+	if (!_nss_setpwent) {
+		return -1;
+	}
+	status = _nss_setpwent();
+	if (status != NSS_STATUS_SUCCESS) {
+		errno = EINVAL;
+		return -1;
+	}
+	return 0;
+}
+
+/*
+  make a endpwent call. 
+  Return 0 on success and -1 on error
+*/
+int nss_endpwent(struct nss_state *nss)
+{
+	enum nss_status (*_nss_endpwent)(void) = find_fn(nss, "endpwent");
+	enum nss_status status;
+	if (!_nss_endpwent) {
+		return -1;
+	}
+	status = _nss_endpwent();
+	if (status != NSS_STATUS_SUCCESS) {
+		errno = EINVAL;
+		return -1;
+	}
+	return 0;
+}
+
+
+/*
+  convert a name to a SID
+  caller frees
+  Return 0 on success and -1 on error
+*/
+int nss_nametosid(struct nss_state *nss, const char *name, char **sid)
+{
+	enum nss_status (*_nss_nametosid)(const char *, char **, char *,
+					  size_t, int *);
+	enum nss_status status;
+	int nss_errno = 0;
+	char buf[200];
+
+	_nss_nametosid = find_fn(nss, "nametosid");
+
+	if (!_nss_nametosid) {
+		return -1;
+	}
+
+	status = _nss_nametosid(name, sid, buf, sizeof(buf), &nss_errno);
+	if (status == NSS_STATUS_NOTFOUND) {
+		errno = ENOENT;
+		return -1;
+	}
+	if (status != NSS_STATUS_SUCCESS) {
+		errno = nss_errno;
+		return -1;
+	}
+
+	*sid = strdup(*sid);
+
+	return 0;
+}
+
+/*
+  convert a SID to a name
+  caller frees
+  Return 0 on success and -1 on error
+*/
+int nss_sidtoname(struct nss_state *nss, const char *sid, char **name)
+{
+	enum nss_status (*_nss_sidtoname)(const char *, char **, char *,
+					  size_t, int *);
+	enum nss_status status;
+	int nss_errno = 0;
+	char buf[200];
+
+	_nss_sidtoname = find_fn(nss, "sidtoname");
+
+	if (!_nss_sidtoname) {
+		return -1;
+	}
+
+	status = _nss_sidtoname(sid, name, buf, sizeof(buf), &nss_errno);
+	if (status == NSS_STATUS_NOTFOUND) {
+		errno = ENOENT;
+		return -1;
+	}
+	if (status != NSS_STATUS_SUCCESS) {
+		errno = nss_errno;
+		return -1;
+	}
+
+	*name = strdup(*name);
+
+	return 0;
+}
+
+/*
+  return a list of group SIDs for a user SID
+  the returned list is NULL terminated
+  Return 0 on success and -1 on error
+*/
+int nss_getusersids(struct nss_state *nss, const char *user_sid, char ***sids)
+{
+	enum nss_status (*_nss_getusersids)(const char *, char **, int *,
+					    char *, size_t, int *);
+	enum nss_status status;
+	int nss_errno = 0;
+	char *s;
+	int i, num_groups = 0;
+	unsigned bufsize = 10;
+	char *buf;
+
+	_nss_getusersids = find_fn(nss, "getusersids");
+
+	if (!_nss_getusersids) {
+		return -1;
+	}
+
+again:
+	buf = malloc(bufsize);
+	if (!buf) {
+		errno = ENOMEM;
+		return -1;
+	}
+
+	status = _nss_getusersids(user_sid, &s, &num_groups, buf, bufsize,
+				  &nss_errno);
+
+	if (status == NSS_STATUS_NOTFOUND) {
+		errno = ENOENT;
+		free(buf);
+		return -1;
+	}
+	
+	if (status == NSS_STATUS_TRYAGAIN) {
+		bufsize *= 2;
+		free(buf);
+		goto again;
+	}
+
+	if (status != NSS_STATUS_SUCCESS) {
+		free(buf);
+		errno = nss_errno;
+		return -1;
+	}
+
+	if (num_groups == 0) {
+		free(buf);
+		return 0;
+	}
+
+	*sids = (char **)malloc(sizeof(char *) * (num_groups+1));
+	if (! *sids) {
+		errno = ENOMEM;
+		free(buf);
+		return -1;
+	}
+
+	for (i=0;i<num_groups;i++) {
+		(*sids)[i] = strdup(s);
+		s += strlen(s) + 1;
+	}
+	(*sids)[i] = NULL;
+
+	free(buf);
+
+	return 0;
+}
+
+/*
+  convert a sid to a uid
+  Return 0 on success and -1 on error
+*/
+int nss_sidtouid(struct nss_state *nss, const char *sid, uid_t *uid)
+{
+	enum nss_status (*_nss_sidtouid)(const char*, uid_t *, int*);
+
+	enum nss_status status;
+	int nss_errno = 0;
+
+	_nss_sidtouid = find_fn(nss, "sidtouid");
+
+	if (!_nss_sidtouid) {
+		return -1;
+	}
+
+	status = _nss_sidtouid(sid, uid, &nss_errno);
+
+	if (status == NSS_STATUS_NOTFOUND) {
+		errno = ENOENT;
+		return -1;
+	}
+
+	if (status != NSS_STATUS_SUCCESS) {
+		errno = nss_errno;
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+  convert a sid to a gid
+  Return 0 on success and -1 on error
+*/
+int nss_sidtogid(struct nss_state *nss, const char *sid, gid_t *gid)
+{
+	enum nss_status (*_nss_sidtogid)(const char*, gid_t *, int*);
+
+	enum nss_status status;
+	int nss_errno = 0;
+
+	_nss_sidtogid = find_fn(nss, "sidtogid");
+
+	if (!_nss_sidtogid) {
+		return -1;
+	}
+
+	status = _nss_sidtogid(sid, gid, &nss_errno);
+
+	if (status == NSS_STATUS_NOTFOUND) {
+		errno = ENOENT;
+		return -1;
+	}
+
+	if (status != NSS_STATUS_SUCCESS) {
+		errno = nss_errno;
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+  convert a uid to a sid
+  caller frees
+  Return 0 on success and -1 on error
+*/
+int nss_uidtosid(struct nss_state *nss, uid_t uid, char **sid)
+{
+	enum nss_status (*_nss_uidtosid)(uid_t, char **, char *,
+					 size_t, int *);
+	enum nss_status status;
+	int nss_errno = 0;
+	char buf[200];
+
+	_nss_uidtosid = find_fn(nss, "uidtosid");
+
+	if (!_nss_uidtosid) {
+		return -1;
+	}
+
+	status = _nss_uidtosid(uid, sid, buf, sizeof(buf), &nss_errno);
+	if (status == NSS_STATUS_NOTFOUND) {
+		errno = ENOENT;
+		return -1;
+	}
+	if (status != NSS_STATUS_SUCCESS) {
+		errno = nss_errno;
+		return -1;
+	}
+
+	*sid = strdup(*sid);
+
+	return 0;
+}
+
+/*
+  convert a gid to a sid
+  caller frees
+  Return 0 on success and -1 on error
+*/
+int nss_gidtosid(struct nss_state *nss, gid_t gid, char **sid)
+{
+	enum nss_status (*_nss_gidtosid)(gid_t, char **, char *,
+					 size_t, int *);
+	enum nss_status status;
+	int nss_errno = 0;
+	char buf[200];
+
+	_nss_gidtosid = find_fn(nss, "gidtosid");
+
+	if (!_nss_gidtosid) {
+		return -1;
+	}
+
+	status = _nss_gidtosid(gid, sid, buf, sizeof(buf), &nss_errno);
+	if (status == NSS_STATUS_NOTFOUND) {
+		errno = ENOENT;
+		return -1;
+	}
+	if (status != NSS_STATUS_SUCCESS) {
+		errno = nss_errno;
+		return -1;
+	}
+
+	*sid = strdup(*sid);
+
+	return 0;
+}
+
diff --git a/examples/nss/nss_winbind.h b/examples/nss/nss_winbind.h
new file mode 100644
index 0000000000..5a124a5a8e
--- /dev/null
+++ b/examples/nss/nss_winbind.h
@@ -0,0 +1,97 @@
+/* 
+   nss sample code for extended winbindd functionality
+
+   Copyright (C) Andrew Tridgell (tridge@samba.org)   
+   Copyright (C) Volker Lendecke (vl@samba.org)
+
+   you are free to use this code in any way you see fit, including
+   without restriction, using this code in your own products. You do
+   not need to give any attribution.
+*/
+
+#define _GNU_SOURCE
+
+#include <pwd.h>
+#include <grp.h>
+
+struct nss_state {
+	void *dl_handle;
+	char *nss_name;
+	char pwnam_buf[512];
+};
+
+/*
+  establish a link to the nss library
+  Return 0 on success and -1 on error
+*/
+int nss_open(struct nss_state *nss, const char *nss_path);
+
+/*
+  close and cleanup a nss state
+*/
+void nss_close(struct nss_state *nss);
+
+/*
+  make a getpwnam call. 
+  Return 0 on success and -1 on error
+*/
+int nss_getpwent(struct nss_state *nss, struct passwd *pwd);
+
+/*
+  make a setpwent call. 
+  Return 0 on success and -1 on error
+*/
+int nss_setpwent(struct nss_state *nss);
+
+/*
+  make a endpwent call. 
+  Return 0 on success and -1 on error
+*/
+int nss_endpwent(struct nss_state *nss);
+
+/*
+  convert a name to a SID
+  caller frees
+  Return 0 on success and -1 on error
+*/
+int nss_nametosid(struct nss_state *nss, const char *name, char **sid);
+
+/*
+  convert a SID to a name
+  caller frees
+  Return 0 on success and -1 on error
+*/
+int nss_sidtoname(struct nss_state *nss, const char *sid, char **name);
+
+/*
+  return a list of group SIDs for a user SID
+  the returned list is NULL terminated
+  Return 0 on success and -1 on error
+*/
+int nss_getusersids(struct nss_state *nss, const char *user_sid, char ***sids);
+
+/*
+  convert a sid to a uid
+  Return 0 on success and -1 on error
+*/
+int nss_sidtouid(struct nss_state *nss, const char *sid, uid_t *uid);
+
+/*
+  convert a sid to a gid
+  Return 0 on success and -1 on error
+*/
+int nss_sidtogid(struct nss_state *nss, const char *sid, gid_t *gid);
+
+/*
+  convert a uid to a sid
+  caller frees
+  Return 0 on success and -1 on error
+*/
+int nss_uidtosid(struct nss_state *nss, uid_t uid, char **sid);
+
+/*
+  convert a gid to a sid
+  caller frees
+  Return 0 on success and -1 on error
+*/
+int nss_gidtosid(struct nss_state *nss, gid_t gid, char **sid);
diff --git a/examples/nss/wbtest.c b/examples/nss/wbtest.c
index fc8f575ef0..14265bd54c 100644
--- a/examples/nss/wbtest.c
+++ b/examples/nss/wbtest.c
@@ -11,7 +11,7 @@
 /*
    compile like this:
 
-      cc -o wbtest wbtest.c -ldl
+      cc -o wbtest wbtest.c nss_winbind.c -ldl
 
    and run like this:
 
@@ -30,271 +30,7 @@
 #include <string.h>
 #include <sys/types.h>
 
-typedef enum nss_status NSS_STATUS;
-
-struct nss_state {
-	void *dl_handle;
-	char *nss_name;
-	char pwnam_buf[512];
-};
-
-/*
-  find a function in the nss library
-*/
-static void *find_fn(struct nss_state *nss, const char *name)
-{
-	void *res;
-	char *s = NULL;
-
-	asprintf(&s, "_nss_%s_%s", nss->nss_name, name);
-	if (!s) {
-		errno = ENOMEM;
-		return NULL;
-	}
-	res = dlsym(nss->dl_handle, s);
-	free(s);
-	if (!res) {
-		errno = ENOENT;
-		return NULL;
-	}
-	return res;
-}
-
-/*
-  establish a link to the nss library
-  Return 0 on success and -1 on error
-*/
-int nss_open(struct nss_state *nss, const char *nss_path)
-{
-	char *p;
-	p = strrchr(nss_path, '_');
-	if (!p) {
-		errno = EINVAL;
-		return -1;
-	}
-
-	nss->nss_name = strdup(p+1);
-	p = strchr(nss->nss_name, '.');
-	if (p) *p = 0;
-
-	nss->dl_handle = dlopen(nss_path, RTLD_LAZY);
-	if (!nss->dl_handle) {
-		free(nss->nss_name);
-		return -1;
-	}
-
-	return 0;
-}
-
-/*
-  close and cleanup a nss state
-*/
-void nss_close(struct nss_state *nss)
-{
-	free(nss->nss_name);
-	dlclose(nss->dl_handle);
-}
-
-/*
-  make a getpwnam call. 
-  Return 0 on success and -1 on error
-*/
-int nss_getpwent(struct nss_state *nss, struct passwd *pwd)
-{
-	NSS_STATUS (*_nss_getpwent_r)(struct passwd *, char *, 
-				      size_t , int *) = find_fn(nss, "getpwent_r");
-	NSS_STATUS status;
-	int nss_errno = 0;
-
-	if (!_nss_getpwent_r) {
-		return -1;
-	}
-
-	status = _nss_getpwent_r(pwd, nss->pwnam_buf, sizeof(nss->pwnam_buf), &nss_errno);
-	if (status == NSS_STATUS_NOTFOUND) {
-		errno = ENOENT;
-		return -1;
-	}
-	if (status != NSS_STATUS_SUCCESS) {
-		errno = nss_errno;
-		return -1;
-	}
-
-	return 0;
-}
-
-/*
-  make a setpwent call. 
-  Return 0 on success and -1 on error
-*/
-int nss_setpwent(struct nss_state *nss)
-{
-	NSS_STATUS (*_nss_setpwent)(void) = find_fn(nss, "setpwent");
-	NSS_STATUS status;
-	if (!_nss_setpwent) {
-		return -1;
-	}
-	status = _nss_setpwent();
-	if (status != NSS_STATUS_SUCCESS) {
-		errno = EINVAL;
-		return -1;
-	}
-	return 0;
-}
-
-/*
-  make a endpwent call. 
-  Return 0 on success and -1 on error
-*/
-int nss_endpwent(struct nss_state *nss)
-{
-	NSS_STATUS (*_nss_endpwent)(void) = find_fn(nss, "endpwent");
-	NSS_STATUS status;
-	if (!_nss_endpwent) {
-		return -1;
-	}
-	status = _nss_endpwent();
-	if (status != NSS_STATUS_SUCCESS) {
-		errno = EINVAL;
-		return -1;
-	}
-	return 0;
-}
-
-
-/*
-  convert a name to a SID
-  caller frees
-  Return 0 on success and -1 on error
-*/
-int nss_nametosid(struct nss_state *nss, const char *name, char **sid)
-{
-	NSS_STATUS (*_nss_nametosid)(const char *, char **, char *, size_t, int *) = 
-		find_fn(nss, "nametosid");
-	NSS_STATUS status;
-	int nss_errno = 0;
-	char buf[200];
-
-	if (!_nss_nametosid) {
-		return -1;
-	}
-
-	status = _nss_nametosid(name, sid, buf, sizeof(buf), &nss_errno);
-	if (status == NSS_STATUS_NOTFOUND) {
-		errno = ENOENT;
-		return -1;
-	}
-	if (status != NSS_STATUS_SUCCESS) {
-		errno = nss_errno;
-		return -1;
-	}
-
-	*sid = strdup(*sid);
-
-	return 0;
-}
-
-/*
-  convert a SID to a name
-  caller frees
-  Return 0 on success and -1 on error
-*/
-int nss_sidtoname(struct nss_state *nss, char *sid, char **name)
-{
-	NSS_STATUS (*_nss_sidtoname)(const char *, char **, char *, size_t, int *) = 
-		find_fn(nss, "sidtoname");
-	NSS_STATUS status;
-	int nss_errno = 0;
-	char buf[200];
-
-	if (!_nss_sidtoname) {
-		return -1;
-	}
-
-	status = _nss_sidtoname(sid, name, buf, sizeof(buf), &nss_errno);
-	if (status == NSS_STATUS_NOTFOUND) {
-		errno = ENOENT;
-		return -1;
-	}
-	if (status != NSS_STATUS_SUCCESS) {
-		errno = nss_errno;
-		return -1;
-	}
-
-	*name = strdup(*name);
-
-	return 0;
-}
-
-/*
-  return a list of group SIDs for a user SID
-  the returned list is NULL terminated
-  Return 0 on success and -1 on error
-*/
-int nss_getusersids(struct nss_state *nss, const char *user_sid, char ***sids)
-{
-	NSS_STATUS (*_nss_getusersids)(const char *, char **, int *, char *, size_t, int *) = 
-		find_fn(nss, "getusersids");
-	NSS_STATUS status;
-	int nss_errno = 0;
-	char *s;
-	int i, num_groups = 0;
-	unsigned bufsize = 10;
-	char *buf;
-
-	if (!_nss_getusersids) {
-		return -1;
-	}
-
-again:
-	buf = malloc(bufsize);
-	if (!buf) {
-		errno = ENOMEM;
-		return -1;
-	}
-
-	status = _nss_getusersids(user_sid, &s, &num_groups, buf, bufsize, &nss_errno);
-	if (status == NSS_STATUS_NOTFOUND) {
-		errno = ENOENT;
-		free(buf);
-		return -1;
-	}
-	
-	if (status == NSS_STATUS_TRYAGAIN) {
-		bufsize *= 2;
-		free(buf);
-		goto again;
-	}
-
-	if (status != NSS_STATUS_SUCCESS) {
-		free(buf);
-		errno = nss_errno;
-		return -1;
-	}
-
-	if (num_groups == 0) {
-		free(buf);
-		return 0;
-	}
-
-	*sids = (char **)malloc(sizeof(char *) * (num_groups+1));
-	if (! *sids) {
-		errno = ENOMEM;
-		free(buf);
-		return -1;
-	}
-
-	for (i=0;i<num_groups;i++) {
-		(*sids)[i] = strdup(s);
-		s += strlen(s) + 1;
-	}
-	(*sids)[i] = NULL;
-
-	free(buf);
-
-	return 0;
-}
-
+#include "nss_winbind.h"
 
 static int nss_test_users(struct nss_state *nss)
 {
diff --git a/source3/nsswitch/winbind_nss_linux.c b/source3/nsswitch/winbind_nss_linux.c
index ac4a861ff1..362047f62b 100644
--- a/source3/nsswitch/winbind_nss_linux.c
+++ b/source3/nsswitch/winbind_nss_linux.c
@@ -1009,3 +1009,141 @@ failed:
 	free_response(&response);
 	return ret;
 }
+
+/* map a sid to a uid */
+NSS_STATUS
+_nss_winbind_sidtouid(const char *sid, uid_t *uid, int *errnop)
+{
+	NSS_STATUS ret;
+	struct winbindd_response response;
+	struct winbindd_request request;
+
+#ifdef DEBUG_NSS
+	fprintf(stderr, "[%5d]: sidtouid %s\n", getpid(), sid);
+#endif
+
+	ZERO_STRUCT(request);
+	ZERO_STRUCT(response);
+
+	strncpy(request.data.sid, sid, sizeof(request.data.sid) - 1);
+	request.data.sid[sizeof(request.data.sid) - 1] = '\0';
+
+	ret = winbindd_request(WINBINDD_SID_TO_UID, &request, &response);
+	if (ret != NSS_STATUS_SUCCESS) {
+		*errnop = errno = EINVAL;
+		goto failed;
+	}
+
+	*uid = response.data.uid;
+
+failed:
+	return ret;
+}
+
+/* map a sid to a gid */
+NSS_STATUS
+_nss_winbind_sidtogid(const char *sid, gid_t *gid, int *errnop)
+{
+	NSS_STATUS ret;
+	struct winbindd_response response;
+	struct winbindd_request request;
+
+#ifdef DEBUG_NSS
+	fprintf(stderr, "[%5d]: sidtogid %s\n", getpid(), sid);
+#endif
+
+	ZERO_STRUCT(request);
+	ZERO_STRUCT(response);
+
+	strncpy(request.data.sid, sid, sizeof(request.data.sid) - 1);
+	request.data.sid[sizeof(request.data.sid) - 1] = '\0';
+
+	ret = winbindd_request(WINBINDD_SID_TO_GID, &request, &response);
+	if (ret != NSS_STATUS_SUCCESS) {
+		*errnop = errno = EINVAL;
+		goto failed;
+	}
+
+	*gid = response.data.gid;
+
+failed:
+	return ret;
+}
+
+/* map a uid to a SID string */
+NSS_STATUS
+_nss_winbind_uidtosid(uid_t uid, char **sid, char *buffer,
+		      size_t buflen, int *errnop)
+{
+	NSS_STATUS ret;
+	struct winbindd_response response;
+	struct winbindd_request request;
+
+#ifdef DEBUG_NSS
+	fprintf(stderr, "[%5d]: uidtosid %s\n", getpid(), name);
+#endif
+
+	ZERO_STRUCT(response);
+	ZERO_STRUCT(request);
+
+	request.data.uid = uid;
+
+	ret = winbindd_request(WINBINDD_UID_TO_SID, &request, &response);
+	if (ret != NSS_STATUS_SUCCESS) {
+		*errnop = errno = EINVAL;
+		goto failed;
+	}
+
+	if (buflen < strlen(response.data.sid.sid)+1) {
+		ret = NSS_STATUS_TRYAGAIN;
+		*errnop = errno = ERANGE;
+		goto failed;
+	}
+
+	*errnop = errno = 0;
+	*sid = buffer;
+	strcpy(*sid, response.data.sid.sid);
+
+failed:
+	free_response(&response);
+	return ret;
+}
+
+/* map a gid to a SID string */
+NSS_STATUS
+_nss_winbind_gidtosid(gid_t gid, char **sid, char *buffer,
+		      size_t buflen, int *errnop)
+{
+	NSS_STATUS ret;
+	struct winbindd_response response;
+	struct winbindd_request request;
+
+#ifdef DEBUG_NSS
+	fprintf(stderr, "[%5d]: gidtosid %s\n", getpid(), name);
+#endif
+
+	ZERO_STRUCT(response);
+	ZERO_STRUCT(request);
+
+	request.data.gid = gid;
+
+	ret = winbindd_request(WINBINDD_GID_TO_SID, &request, &response);
+	if (ret != NSS_STATUS_SUCCESS) {
+		*errnop = errno = EINVAL;
+		goto failed;
+	}
+
+	if (buflen < strlen(response.data.sid.sid)+1) {
+		ret = NSS_STATUS_TRYAGAIN;
+		*errnop = errno = ERANGE;
+		goto failed;
+	}
+
+	*errnop = errno = 0;
+	*sid = buffer;
+	strcpy(*sid, response.data.sid.sid);
+
+failed:
+	free_response(&response);
+	return ret;
+}