nwrap: Add a hash table to the nwrap structure

The hash table will hold hostnames and ips internally. The new
environment variable which is introduced is NSS_WRAPPER_MAX_HOSTENTS. It
sets the maximum count of hostent (hostnames and ips) structs which the
hash table can hold.

Signed-off-by: Robin Hack <hack.robin@gmail.com>
Reviewed-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Michael Adam <obnox@samba.org>

diff --git a/lib/nss_wrapper/nss_wrapper.c b/lib/nss_wrapper/nss_wrapper.c
index 94cc4cf7e4f9381d1c2f71ba79915f99978a6d5b..ae57e1877d1021fca88d4ce827ef1f4e047ffb5f 100644 (file)
--- a/lib/nss_wrapper/nss_wrapper.c
+++ b/lib/nss_wrapper/nss_wrapper.c
@@ -50,6 +50,7 @@
 #include <unistd.h>
 #include <ctype.h>
 
+#include <search.h>
 #include <assert.h>
 
 /*
@@ -680,15 +681,25 @@ struct nwrap_addrdata {
        char *h_addr_ptrs[2]; /* host_addr pointer + NULL */
 };
 
+static size_t max_hostents = 100;
+
 struct nwrap_entdata {
        struct nwrap_addrdata *addr;
        struct hostent ht;
+
+       struct nwrap_vector nwrap_addrdata;
+
+       ssize_t aliases_count;
+
+       struct nwrap_entdata *ed_next;
+       struct nwrap_entdata *ed_tail;
 };
 
 struct nwrap_he {
        struct nwrap_cache *cache;
 
        struct nwrap_entdata *list;
+       struct nwrap_vector entdata;
        int num;
        int idx;
 };
@@ -1415,10 +1426,36 @@ static void nwrap_backend_init(struct nwrap_main *r)
 static void nwrap_init(void)
 {
        static bool initialized;
+       const char *env;
+       char *endptr;
+       size_t max_hostents_tmp;
 
        if (initialized) return;
        initialized = true;
 
+       env = getenv("NSS_WRAPPER_MAX_HOSTENTS");
+       if (env != NULL) {
+               max_hostents_tmp = (size_t)strtol(env, &endptr, 10);
+               if (((env != '\0') && (endptr == '\0')) ||
+                   (max_hostents_tmp == 0)) {
+                       NWRAP_LOG(NWRAP_LOG_DEBUG,
+                                 "Error parsing NSS_WRAPPER_MAX_HOSTENTS "
+                                 "value or value is too small. "
+                                 "Using default value: %lu.",
+                                 max_hostents);
+               } else {
+                       max_hostents = max_hostents_tmp;
+               }
+       }
+       /* Initialize hash table */
+       NWRAP_LOG(NWRAP_LOG_DEBUG,
+                 "Initializing hash table of size %lu items.", max_hostents);
+       if (hcreate(max_hostents) == 0) {
+               NWRAP_LOG(NWRAP_LOG_ERROR,
+                         "Failed to initialize hash table");
+               return;
+       }
+
        nwrap_main_global = &__nwrap_main_global;
 
        nwrap_libc_init(nwrap_main_global);
@@ -4915,4 +4952,6 @@ void nwrap_destructor(void)
                SAFE_FREE(nwrap_he_global.list);
                nwrap_he_global.num = 0;
        }
+
+       hdestroy();
 }