nwrap: Try different backends for gethostbyname[2][_r]

Signed-off-by: Samuel Cabrero <scabrero@suse.de>
Reviewed-by: Andreas Schneider <asn@samba.org>

diff --git a/src/nss_wrapper.c b/src/nss_wrapper.c
index 269701079eb7e7e7d0ea984ca5bc4be286b5ee35..9b3e18087f9eda2df17b15e615875434bf5fa9cb 100644 (file)
--- a/src/nss_wrapper.c
+++ b/src/nss_wrapper.c
@@ -399,6 +399,10 @@ struct nwrap_module_nss_fns {
                                           int af, struct hostent *result,
                                           char *buffer, size_t buflen,
                                           int *errnop, int *h_errnop);
+       NSS_STATUS (*_nss_gethostbyname2_r)(const char *name, int af,
+                                           struct hostent *result,
+                                           char *buffer, size_t buflen,
+                                           int *errnop, int *h_errnop);
 };
 
 struct nwrap_backend {
@@ -409,6 +413,8 @@ struct nwrap_backend {
        struct nwrap_module_nss_fns *fns;
 };
 
+struct nwrap_vector;
+
 struct nwrap_ops {
        struct passwd * (*nw_getpwnam)(struct nwrap_backend *b,
                                       const char *name);
@@ -447,6 +453,15 @@ struct nwrap_ops {
        struct hostent *(*nw_gethostbyaddr)(struct nwrap_backend *b,
                                            const void *addr,
                                            socklen_t len, int type);
+       struct hostent *(*nw_gethostbyname)(struct nwrap_backend *b,
+                                           const char *name);
+       struct hostent *(*nw_gethostbyname2)(struct nwrap_backend *b,
+                                            const char *name, int af);
+       int             (*nw_gethostbyname2_r)(struct nwrap_backend *b,
+                                              const char *name, int af,
+                                              struct hostent *hedst,
+                                              char *buf, size_t buflen,
+                                              struct hostent **hedstp);
 };
 
 /* Public prototypes */
@@ -495,6 +510,15 @@ static void nwrap_files_endgrent(struct nwrap_backend *b);
 static struct hostent *nwrap_files_gethostbyaddr(struct nwrap_backend *b,
                                                 const void *addr,
                                                 socklen_t len, int type);
+static struct hostent *nwrap_files_gethostbyname(struct nwrap_backend *b,
+                                                const char *name);
+static struct hostent *nwrap_files_gethostbyname2(struct nwrap_backend *b,
+                                                 const char *name, int af);
+static int nwrap_files_gethostbyname2_r(struct nwrap_backend *b,
+                                       const char *name, int af,
+                                       struct hostent *hedst,
+                                       char *buf, size_t buflen,
+                                       struct hostent **hedstp);
 
 /* prototypes for module backend */
 
@@ -535,6 +559,15 @@ static int nwrap_module_initgroups(struct nwrap_backend *b,
 static struct hostent *nwrap_module_gethostbyaddr(struct nwrap_backend *b,
                                                  const void *addr,
                                                  socklen_t len, int type);
+static struct hostent *nwrap_module_gethostbyname(struct nwrap_backend *b,
+                                                 const char *name);
+static struct hostent *nwrap_module_gethostbyname2(struct nwrap_backend *b,
+                                                  const char *name, int af);
+static int nwrap_module_gethostbyname2_r(struct nwrap_backend *b,
+                                        const char *name, int af,
+                                        struct hostent *hedst,
+                                        char *buf, size_t buflen,
+                                        struct hostent **hedstp);
 
 struct nwrap_ops nwrap_files_ops = {
        .nw_getpwnam    = nwrap_files_getpwnam,
@@ -555,6 +588,9 @@ struct nwrap_ops nwrap_files_ops = {
        .nw_getgrent_r  = nwrap_files_getgrent_r,
        .nw_endgrent    = nwrap_files_endgrent,
        .nw_gethostbyaddr       = nwrap_files_gethostbyaddr,
+       .nw_gethostbyname       = nwrap_files_gethostbyname,
+       .nw_gethostbyname2      = nwrap_files_gethostbyname2,
+       .nw_gethostbyname2_r    = nwrap_files_gethostbyname2_r,
 };
 
 struct nwrap_ops nwrap_module_ops = {
@@ -576,6 +612,9 @@ struct nwrap_ops nwrap_module_ops = {
        .nw_getgrent_r  = nwrap_module_getgrent_r,
        .nw_endgrent    = nwrap_module_endgrent,
        .nw_gethostbyaddr       = nwrap_module_gethostbyaddr,
+       .nw_gethostbyname       = nwrap_module_gethostbyname,
+       .nw_gethostbyname2      = nwrap_module_gethostbyname2,
+       .nw_gethostbyname2_r    = nwrap_module_gethostbyname2_r,
 };
 
 struct nwrap_libc {
@@ -1492,6 +1531,8 @@ static struct nwrap_module_nss_fns *nwrap_load_module_fns(struct nwrap_backend *
                nwrap_load_module_fn(b, "endgrent");
        *(void **)(&fns->_nss_gethostbyaddr_r) =
                nwrap_load_module_fn(b, "gethostbyaddr_r");
+       *(void **)(&fns->_nss_gethostbyname2_r) =
+               nwrap_load_module_fn(b, "gethostbyname2_r");
 
        return fns;
 }
@@ -3530,9 +3571,9 @@ static void nwrap_files_endgrent(struct nwrap_backend *b)
 }
 
 /* hosts functions */
-static int nwrap_files_gethostbyname(const char *name, int af,
-                                    struct hostent *result,
-                                    struct nwrap_vector *addr_list)
+static int nwrap_files_internal_gethostbyname(const char *name, int af,
+                                             struct hostent *result,
+                                             struct nwrap_vector *addr_list)
 {
        struct nwrap_entlist *el;
        struct hostent *he;
@@ -3628,11 +3669,11 @@ no_ent:
        return -1;
 }
 
-#ifdef HAVE_GETHOSTBYNAME_R
-static int nwrap_gethostbyname_r(const char *name,
-                                struct hostent *ret,
-                                char *buf, size_t buflen,
-                                struct hostent **result, int *h_errnop)
+static int nwrap_files_gethostbyname2_r(struct nwrap_backend *b,
+                                       const char *name, int af,
+                                       struct hostent *hedst,
+                                       char *buf, size_t buflen,
+                                       struct hostent **hedstp)
 {
        struct nwrap_vector *addr_list = malloc(sizeof(struct nwrap_vector));
        union {
@@ -3641,6 +3682,9 @@ static int nwrap_gethostbyname_r(const char *name,
        } g;
        int rc;
 
+       (void) b; /* unused */
+       (void) af; /* unused */
+
        if (addr_list == NULL) {
                NWRAP_LOG(NWRAP_LOG_ERROR,
                          "Unable to allocate memory for address list");
@@ -3650,9 +3694,9 @@ static int nwrap_gethostbyname_r(const char *name,
 
        ZERO_STRUCTP(addr_list);
 
-       rc = nwrap_files_gethostbyname(name, AF_UNSPEC, ret, addr_list);
+       rc = nwrap_files_internal_gethostbyname(name, AF_UNSPEC, hedst,
+                                               addr_list);
        if (rc == -1) {
-               *h_errnop = h_errno;
                if (addr_list->items != NULL) {
                        free(addr_list->items);
                }
@@ -3676,11 +3720,32 @@ static int nwrap_gethostbyname_r(const char *name,
        free(addr_list);
 
        g.ptr = buf;
-       ret->h_addr_list = g.list;
-       *result = ret;
+       hedst->h_addr_list = g.list;
+       *hedstp = hedst;
        return 0;
 }
 
+#ifdef HAVE_GETHOSTBYNAME_R
+static int nwrap_gethostbyname_r(const char *name,
+                                struct hostent *ret,
+                                char *buf, size_t buflen,
+                                struct hostent **result, int *h_errnop)
+{
+       int rc;
+       size_t i;
+
+       for (i=0; i < nwrap_main_global->num_backends; i++) {
+               struct nwrap_backend *b = &nwrap_main_global->backends[i];
+               rc = b->ops->nw_gethostbyname2_r(b, name, AF_UNSPEC, ret,
+                                                buf, buflen, result);
+               if (rc == 0) {
+                       return 0;
+               }
+       }
+       *h_errnop = h_errno;
+       return ENOENT;
+}
+
 int gethostbyname_r(const char *name,
                    struct hostent *ret,
                    char *buf, size_t buflen,
@@ -3699,6 +3764,42 @@ int gethostbyname_r(const char *name,
 }
 #endif
 
+#ifdef HAVE_GETHOSTBYNAME2_R
+static int nwrap_gethostbyname2_r(const char *name, int af,
+                                struct hostent *ret,
+                                char *buf, size_t buflen,
+                                struct hostent **result, int *h_errnop)
+{
+       int rc;
+       size_t i;
+
+       for (i=0; i < nwrap_main_global->num_backends; i++) {
+               struct nwrap_backend *b = &nwrap_main_global->backends[i];
+               rc = b->ops->nw_gethostbyname2_r(b, name, af, ret,
+                                                buf, buflen, result);
+               if (rc == 0) {
+                       return 0;
+               }
+       }
+       *h_errnop = h_errno;
+       return ENOENT;
+}
+
+int gethostbyname2_r(const char *name, int af,
+                    struct hostent *ret,
+                    char *buf, size_t buflen,
+                    struct hostent **result, int *h_errnop)
+{
+       if (!nss_wrapper_hosts_enabled()) {
+               return libc_gethostbyname2_r(name, af, ret, buf, buflen,
+                                            result, h_errnop);
+       }
+
+       return nwrap_gethostbyname2_r(name, af, ret, buf, buflen, result,
+                                     h_errnop);
+}
+#endif
+
 static int nwrap_files_getaddrinfo(const char *name,
                                   unsigned short port,
                                   const struct addrinfo *hints,
@@ -4401,6 +4502,129 @@ again:
                SAFE_FREE(buf);
                return NULL;
        }
+
+       return &he;
+}
+
+static int nwrap_module_gethostbyname2_r(struct nwrap_backend *b,
+                                        const char *name, int af,
+                                        struct hostent *hedst,
+                                        char *buf, size_t buflen,
+                                        struct hostent **hedstp)
+{
+       NSS_STATUS status;
+
+       *hedstp = NULL;
+
+       if (b->fns->_nss_gethostbyname2_r == NULL) {
+               return ENOENT;
+       }
+
+       status = b->fns->_nss_gethostbyname2_r(name, af, hedst,
+                                              buf, buflen, &errno, &h_errno);
+       switch (status) {
+       case NSS_STATUS_SUCCESS:
+               *hedstp = hedst;
+               return 0;
+       case NSS_STATUS_NOTFOUND:
+               if (errno != 0) {
+                       return errno;
+               }
+               return ENOENT;
+       case NSS_STATUS_TRYAGAIN:
+               if (errno != 0) {
+                       return errno;
+               }
+               return ERANGE;
+       default:
+               if (errno != 0) {
+                       return errno;
+               }
+               return status;
+       }
+}
+
+static struct hostent *nwrap_module_gethostbyname(struct nwrap_backend *b,
+                                                 const char *name)
+{
+       static struct hostent he;
+       static char *buf = NULL;
+       static size_t buflen = 1000;
+       NSS_STATUS status;
+
+       if (b->fns->_nss_gethostbyname2_r == NULL) {
+               return NULL;
+       }
+
+       if (buf == NULL) {
+               buf = (char *)malloc(buflen);
+               if (buf == NULL) {
+                       return NULL;
+               }
+       }
+
+again:
+       status = b->fns->_nss_gethostbyname2_r(name, AF_UNSPEC, &he,
+                                              buf, buflen, &errno, &h_errno);
+       if (status == NSS_STATUS_TRYAGAIN) {
+               buflen *= 2;
+               buf = (char *)realloc(buf, buflen);
+               if (buf == NULL) {
+                       return NULL;
+               }
+               goto again;
+       }
+       if (status == NSS_STATUS_NOTFOUND) {
+               SAFE_FREE(buf);
+               return NULL;
+       }
+       if (status != NSS_STATUS_SUCCESS) {
+               SAFE_FREE(buf);
+               return NULL;
+       }
+
+       return &he;
+}
+
+static struct hostent *nwrap_module_gethostbyname2(struct nwrap_backend *b,
+                                                  const char *name, int af)
+{
+       static struct hostent he;
+       static char *buf = NULL;
+       static size_t buflen = 1000;
+       NSS_STATUS status;
+
+       if (b->fns->_nss_gethostbyname2_r == NULL) {
+               return NULL;
+       }
+
+       if (buf == NULL) {
+               buf = (char *)malloc(buflen);
+               if (buf == NULL) {
+                       return NULL;
+               }
+       }
+
+again:
+       status = b->fns->_nss_gethostbyname2_r(name, af, &he,
+                                              buf, buflen, &errno, &h_errno);
+       if (status == NSS_STATUS_TRYAGAIN) {
+               buflen *= 2;
+               buf = (char *)realloc(buf, buflen);
+               if (buf == NULL) {
+                       return NULL;
+               }
+               goto again;
+       }
+       if (status == NSS_STATUS_NOTFOUND) {
+               SAFE_FREE(buf);
+               return NULL;
+       }
+       if (status != NSS_STATUS_SUCCESS) {
+               SAFE_FREE(buf);
+               return NULL;
+       }
+
        return &he;
 }
 
@@ -5197,6 +5421,7 @@ void endhostent(void)
 }
 #endif /* HAVE_SOLARIS_ENDHOSTENT */
 
+
 #ifdef BSD
 /* BSD implementation stores data in thread local storage but GLIBC does not */
 static __thread struct hostent user_he;
@@ -5205,12 +5430,37 @@ static __thread struct nwrap_vector user_addrlist;
 static struct hostent user_he;
 static struct nwrap_vector user_addrlist;
 #endif /* BSD */
+
+static struct hostent *nwrap_files_gethostbyname(struct nwrap_backend *b,
+                                                const char *name)
+{
+       int ret;
+
+       (void) b; /* unused */
+
+       ret = nwrap_files_internal_gethostbyname(name, AF_UNSPEC, &user_he,
+                                                &user_addrlist);
+       if (ret == 0) {
+               return &user_he;
+       }
+
+       return NULL;
+}
+
 static struct hostent *nwrap_gethostbyname(const char *name)
 {
-       if (nwrap_files_gethostbyname(name, AF_UNSPEC, &user_he, &user_addrlist) == -1) {
-               return NULL;
+       size_t i;
+       struct hostent *he = NULL;
+
+       for (i=0; i < nwrap_main_global->num_backends; i++) {
+               struct nwrap_backend *b = &nwrap_main_global->backends[i];
+               he = b->ops->nw_gethostbyname(b, name);
+               if (he != NULL) {
+                       return he;
+               }
        }
-       return &user_he;
+
+       return NULL;
 }
 
 struct hostent *gethostbyname(const char *name)
@@ -5232,12 +5482,37 @@ static __thread struct nwrap_vector user_addrlist2;
 static struct hostent user_he2;
 static struct nwrap_vector user_addrlist2;
 #endif /* BSD */
+
+static struct hostent *nwrap_files_gethostbyname2(struct nwrap_backend *b,
+                                                 const char *name, int af)
+{
+       int ret;
+
+       (void) b; /* unused */
+
+       ret = nwrap_files_internal_gethostbyname(name, af, &user_he2,
+                                                &user_addrlist2);
+       if (ret == 0) {
+               return &user_he2;
+       }
+
+       return NULL;
+}
+
 static struct hostent *nwrap_gethostbyname2(const char *name, int af)
 {
-       if (nwrap_files_gethostbyname(name, af, &user_he2, &user_addrlist2) == -1) {
-               return NULL;
+       size_t i;
+       struct hostent *he = NULL;
+
+       for (i=0; i < nwrap_main_global->num_backends; i++) {
+               struct nwrap_backend *b = &nwrap_main_global->backends[i];
+               he = b->ops->nw_gethostbyname2(b, name, af);
+               if (he != NULL) {
+                       return he;
+               }
        }
-       return &user_he2;
+
+       return NULL;
 }
 
 struct hostent *gethostbyname2(const char *name, int af)