backends: support absolute/relative paths to nsswitch modules

diff --git a/backends/nss.c b/backends/nss.c
index 421ed95149af5446e81ced0bbc2fd7a907ac2c62..2ac46eedffb89fd89ad4f7cc4a9d2501dc157b25 100644 (file)
--- a/backends/nss.c
+++ b/backends/nss.c
@@ -31,8 +31,8 @@
 
 struct priv_nss {
        char *name;
-       char filename[1024];
-       char *api;
+       char *filename;
+       const char *api;
        void *dl_handle;
        /* gethostbyname:
         *
@@ -94,74 +94,112 @@ combine_statuses(int s4, int s6)
 static void
 try_symbol_pattern(netresolve_query_t query, struct priv_nss *priv, void **f, const char *pattern, const char *api)
 {
-       char symbol[1024];
+       char symbol[1024] = { 0 };
 
-       if (priv->api && strcmp(priv->api, api)) {
-               debug("%s API ignored: environment setting\n", api);
+       if (priv->api && strcmp(priv->api, api))
                return;
-       }
 
        snprintf(symbol, sizeof symbol, pattern, priv->name);
-
        *f = dlsym(priv->dl_handle, symbol);
 
-       if (!*f) {
-               debug("%s API not loaded: %s\n", api, dlerror());
-       }
+       if (*f)
+               debug("loaded %s (%s)\n", symbol, api);
+       else
+               debug("not loaded %s (%s): %s\n", symbol, api, dlerror());
 }
 
-void
-start(netresolve_query_t query, char **settings)
+static void
+initialize(struct priv_nss *priv, netresolve_query_t query, char **settings)
 {
-       struct priv_nss *priv = netresolve_backend_new_priv(query, sizeof *priv);
-       const char *node = netresolve_backend_get_nodename(query);
-       int family = netresolve_backend_get_family(query);
-       int status = NSS_STATUS_UNAVAIL;
+       char *p;
 
-       if (!priv || !settings || !*settings) {
-               netresolve_backend_failed(query);
+       if (!settings || !*settings) {
+               error("missing argument");
                return;
        }
 
-       /* Load nsswitch backend: */
-       priv->name = strdup(*settings);
-       priv->api = secure_getenv("NETRESOLVE_NSS_API");
-       snprintf(priv->filename, sizeof priv->filename, "libnss_%s.so.2", priv->name);
+       /* parse settings */
+       priv->name = strdup(*settings++);
+       if (*settings)
+               priv->api = *settings++;
+       if ((p = strrchr(priv->name, '/'))) {
+               priv->filename = strdup(priv->name);
+               p++;
+               if (!strncmp(p, "libnss_", 7)) {
+                       p += 7;
+                       memmove(priv->name, p, strlen(p));
+               }
+               if ((p = strchr(priv->name, '.')))
+                       *p = '\0';
+       } else
+               if (asprintf(&priv->filename, "libnss_%s.so.2", priv->name) == -1)
+                       priv->filename = NULL;
+
+       /* load nsswitch module */
+       debug("loading NSS module: %s\n", priv->filename);
        priv->dl_handle = dlopen(priv->filename, RTLD_LAZY);
        if (!priv->dl_handle) {
                error("%s\n", dlerror());
-               netresolve_backend_failed(query);
                return;
        }
+
+       /* find nsswitch entry points */
        try_symbol_pattern(query, priv, (void *) &priv->gethostbyname_r, "_nss_%s_gethostbyname_r", "gethostbyname");
        try_symbol_pattern(query, priv, (void *) &priv->gethostbyname2_r, "_nss_%s_gethostbyname2_r", "gethostbyname2");
        try_symbol_pattern(query, priv, (void *) &priv->gethostbyname3_r, "_nss_%s_gethostbyname3_r", "gethostbyname3");
        try_symbol_pattern(query, priv, (void *) &priv->gethostbyname4_r, "_nss_%s_gethostbyname4_r", "gethostbyname4");
 
+       free(priv->name);
+       priv->name = NULL;
+       free(priv->filename);
+       priv->filename = NULL;
+}
+
+static void
+finalize(struct priv_nss *priv)
+{
+       dlclose(priv->dl_handle);
+}
+
+void
+start(netresolve_query_t query, char **settings)
+{
+       const char *node = netresolve_backend_get_nodename(query);
+       int family = netresolve_backend_get_family(query);
+       struct priv_nss priv = { 0 };
+       enum nss_status status = NSS_STATUS_UNAVAIL;
+
+       initialize(&priv, query, settings);
+
+       if (!priv.dl_handle) {
+               netresolve_backend_failed(query);
+               return;
+       }
+
        /*if (priv->gethostbyname4_r) {
                TODO
-       } else*/ if (node && (priv->gethostbyname3_r || priv->gethostbyname2_r)) {
+       } else*/ if (node && (priv.gethostbyname3_r || priv.gethostbyname2_r)) {
                char buffer4[SIZE], buffer6[SIZE];
                int status4 = NSS_STATUS_NOTFOUND, status6 = NSS_STATUS_NOTFOUND;
                struct hostent he4, he6;
                int errnop, h_errnop;
 
-               if (priv->gethostbyname3_r) {
+               if (priv.gethostbyname3_r) {
                        int32_t ttl;
                        char *canonname = NULL;
 
                        if (family == AF_INET || family == AF_UNSPEC)
-                               status4 = DL_CALL_FCT(priv->gethostbyname3_r, (node, AF_INET,
+                               status4 = DL_CALL_FCT(priv.gethostbyname3_r, (node, AF_INET,
                                        &he4, buffer4, sizeof buffer4, &errnop, &h_errnop, &ttl, &canonname));
                        if (family == AF_INET6 || family == AF_UNSPEC)
-                               status6 = DL_CALL_FCT(priv->gethostbyname3_r, (node, AF_INET6,
+                               status6 = DL_CALL_FCT(priv.gethostbyname3_r, (node, AF_INET6,
                                        &he6, buffer6, sizeof buffer6, &errnop, &h_errnop, &ttl, &canonname));
                } else {
                        if (family == AF_INET || family == AF_UNSPEC)
-                               status4 = DL_CALL_FCT(priv->gethostbyname2_r, (node, AF_INET,
+                               status4 = DL_CALL_FCT(priv.gethostbyname2_r, (node, AF_INET,
                                        &he4, buffer4, sizeof buffer4, &errnop, &h_errnop));
                        if (family == AF_INET6 || family == AF_UNSPEC)
-                               status6 = DL_CALL_FCT(priv->gethostbyname2_r, (node, AF_INET6,
+                               status6 = DL_CALL_FCT(priv.gethostbyname2_r, (node, AF_INET6,
                                        &he6, buffer6, sizeof buffer6, &errnop, &h_errnop));
                }
 
@@ -172,12 +210,12 @@ start(netresolve_query_t query, char **settings)
                        if (status6 == NSS_STATUS_SUCCESS)
                                netresolve_backend_apply_hostent(query, &he6, 0, 0, 0, 0, 0, 0);
                }
-       } else if (node && priv->gethostbyname_r) {
+       } else if (node && priv.gethostbyname_r) {
                char buffer[SIZE];
                int errnop, h_errnop;
                struct hostent he;
 
-               status = DL_CALL_FCT(priv->gethostbyname_r, (node,
+               status = DL_CALL_FCT(priv.gethostbyname_r, (node,
                        &he, buffer, sizeof buffer, &errnop, &h_errnop));
 
                if (status == NSS_STATUS_SUCCESS) {
@@ -185,6 +223,8 @@ start(netresolve_query_t query, char **settings)
                }
        }
 
+       finalize(&priv);
+
        if (status == NSS_STATUS_SUCCESS)
                netresolve_backend_finished(query);
        else