added a wbtest program that shows how to access winbindd extended nss

functionality directly from an application.

This is under a liberal license as we want application vendors to be
able to use the example code
(This used to be commit 8d848de45d75bf6ac69cb921e04abf36a66117c4)

diff --git a/examples/nss/wbtest.c b/examples/nss/wbtest.c
new file mode 100644 (file)
index 0000000..fc8f575
--- /dev/null
+++ b/examples/nss/wbtest.c
@@ -0,0 +1,375 @@
+/* 
+   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.
+*/
+
+/*
+   compile like this:
+
+      cc -o wbtest wbtest.c -ldl
+
+   and run like this:
+
+      ./wbtest /lib/libnss_winbind.so
+*/
+
+#define _GNU_SOURCE
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <nss.h>
+#include <dlfcn.h>
+#include <pwd.h>
+#include <grp.h>
+#include <errno.h>
+#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;
+}
+
+
+static int nss_test_users(struct nss_state *nss)
+{
+       struct passwd pwd;
+
+       if (nss_setpwent(nss) != 0) {
+               perror("setpwent");
+               return -1;
+       }
+
+       /* loop over all users */
+       while ((nss_getpwent(nss, &pwd) == 0)) {
+               char *sid, **group_sids, *name2;
+               int i;
+
+               printf("User %s\n", pwd.pw_name);
+               if (nss_nametosid(nss, pwd.pw_name, &sid) != 0) {
+                       perror("nametosid");
+                       return -1;
+               }
+               printf("\tSID %s\n", sid);
+
+               if (nss_sidtoname(nss, sid, &name2) != 0) {
+                       perror("sidtoname");
+                       return -1;
+               }
+               printf("\tSID->name %s\n", name2);
+
+               if (nss_getusersids(nss, sid, &group_sids) != 0) {
+                       perror("getusersids");
+                       return -1;
+               }
+
+               printf("\tGroups:\n");
+               for (i=0; group_sids[i]; i++) {
+                       printf("\t\t%s\n", group_sids[i]);
+                       free(group_sids[i]);
+               }
+
+               free(sid);
+               free(name2);
+               free(group_sids);
+       }
+
+
+       if (nss_endpwent(nss) != 0) {
+               perror("endpwent");
+               return -1;
+       }
+
+       return 0;
+}
+
+
+/*
+  main program. It lists all users, listing user SIDs for each user
+ */
+int main(int argc, char *argv[])
+{      
+       struct nss_state nss;
+       const char *so_path = "/lib/libnss_winbind.so";
+       int ret;
+
+       if (argc > 1) {
+               so_path = argv[1];
+       }
+
+       if (nss_open(&nss, so_path) != 0) {
+               perror("nss_open");
+               exit(1);
+       }
+
+       ret = nss_test_users(&nss);
+
+       nss_close(&nss);
+
+       return ret;
+}