Make res_init() work again.
Change 75830fb836621ebbcf68155e466983eb231f9ca1 to fix _nres
initialization to be thread safe accidentally introduced a behavior
change whereby res_init() became a no-op. It also failed to remove all
direct accesses to _nres.
Move the file over to C++ so we can let RAII ensure we're always holding
a lock while using the global state, make all callers access the global
state via this class, and restore the previous behavior of res_init().
Test: atest DnsResolverTest
Bug: 166235340
Change-Id: Ib390a7eac063bc0ff5eeba755e8c74ef1383004e
diff --git a/libc/dns/resolv/res_data.c b/libc/dns/resolv/res_data.c
deleted file mode 100644
index 4f8df69..0000000
--- a/libc/dns/resolv/res_data.c
+++ /dev/null
@@ -1,295 +0,0 @@
-/* $NetBSD: res_data.c,v 1.8 2004/06/09 18:07:03 christos Exp $ */
-
-/*
- * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
- * Copyright (c) 1995-1999 by Internet Software Consortium.
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
- * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
-
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#ifdef notdef
-static const char rcsid[] = "Id: res_data.c,v 1.1.206.2 2004/03/16 12:34:18 marka Exp";
-#else
-__RCSID("$NetBSD: res_data.c,v 1.8 2004/06/09 18:07:03 christos Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
-
-
-
-#include <sys/types.h>
-#include <sys/param.h>
-#include <sys/socket.h>
-#include <sys/time.h>
-
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#include <arpa/nameser.h>
-
-#include <ctype.h>
-#include <netdb.h>
-#include "resolv_private.h"
-#include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
-
-__LIBC_HIDDEN__
-const char * const _res_opcodes[] = {
- "QUERY",
- "IQUERY",
- "CQUERYM",
- "CQUERYU", /* experimental */
- "NOTIFY", /* experimental */
- "UPDATE",
- "6",
- "7",
- "8",
- "9",
- "10",
- "11",
- "12",
- "13",
- "ZONEINIT",
- "ZONEREF",
-};
-
-#ifdef BIND_UPDATE
-const char * const _res_sectioncodes[] = {
- "ZONE",
- "PREREQUISITES",
- "UPDATE",
- "ADDITIONAL",
-};
-#endif
-
-#ifndef __BIND_NOSTATIC
-extern struct __res_state _nres;
-
-/* Proto. */
-
-int res_ourserver_p(const res_state, const struct sockaddr *);
-
-static pthread_once_t once_control = PTHREAD_ONCE_INIT;
-
-static void init_once(void) {
- extern int __res_vinit(res_state, int);
-#ifdef COMPAT__RES
- /*
- * Compatibility with program that were accessing _res directly
- * to set options. We keep another struct res that is the same
- * size as the original res structure, and then copy fields to
- * it so that we achieve the same initialization
- */
- extern void *__res_get_old_state(void);
- extern void __res_put_old_state(void *);
- res_state ores = __res_get_old_state();
-
- if (ores->options != 0)
- _nres.options = ores->options;
- if (ores->retrans != 0)
- _nres.retrans = ores->retrans;
- if (ores->retry != 0)
- _nres.retry = ores->retry;
-#endif
-
- /*
- * These three fields used to be statically initialized. This made
- * it hard to use this code in a shared library. It is necessary,
- * now that we're doing dynamic initialization here, that we preserve
- * the old semantics: if an application modifies one of these three
- * fields of _res before res_init() is called, res_init() will not
- * alter them. Of course, if an application is setting them to
- * _zero_ before calling res_init(), hoping to override what used
- * to be the static default, we can't detect it and unexpected results
- * will follow. Zero for any of these fields would make no sense,
- * so one can safely assume that the applications were already getting
- * unexpected results.
- *
- * _nres.options is tricky since some apps were known to diddle the bits
- * before res_init() was first called. We can't replicate that semantic
- * with dynamic initialization (they may have turned bits off that are
- * set in RES_DEFAULT). Our solution is to declare such applications
- * "broken". They could fool us by setting RES_INIT but none do (yet).
- */
- if (!_nres.retrans)
- _nres.retrans = RES_TIMEOUT;
- if (!_nres.retry)
- _nres.retry = 4;
- if (!(_nres.options & RES_INIT))
- _nres.options = RES_DEFAULT;
-
- /*
- * This one used to initialize implicitly to zero, so unless the app
- * has set it to something in particular, we can randomize it now.
- */
- if (!_nres.id)
- _nres.id = res_randomid();
-
- __res_vinit(&_nres, 1);
-#ifdef COMPAT__RES
- __res_put_old_state(&_nres);
-#endif
-}
-
-int
-res_init(void) {
- pthread_once(&once_control, init_once);
- return 0;
-}
-
-static res_state get_static_res_state() {
- pthread_once(&once_control, init_once);
- return &_nres;
-}
-
-void
-p_query(const u_char *msg) {
- fp_query(msg, stdout);
-}
-
-void
-fp_query(const u_char *msg, FILE *file) {
- fp_nquery(msg, PACKETSZ, file);
-}
-
-void
-fp_nquery(const u_char *msg, int len, FILE *file) {
- res_pquery(get_static_res_state(), msg, len, file);
-}
-
-int
-res_mkquery(int op, /* opcode of query */
- const char *dname, /* domain name */
- int class, int type, /* class and type of query */
- const u_char *data, /* resource record data */
- int datalen, /* length of data */
- const u_char *newrr_in, /* new rr for modify or append */
- u_char *buf, /* buffer to put query */
- int buflen) /* size of buffer */
-{
- return (res_nmkquery(get_static_res_state(), op, dname, class, type,
- data, datalen,
- newrr_in, buf, buflen));
-}
-
-#ifdef _LIBRESOLV
-int
-res_mkupdate(ns_updrec *rrecp_in, u_char *buf, int buflen) {
- return (res_nmkupdate(get_static_res_state(), rrecp_in, buf, buflen));
-}
-#endif
-
-int
-res_query(const char *name, /* domain name */
- int class, int type, /* class and type of query */
- u_char *answer, /* buffer to put answer */
- int anslen) /* size of answer buffer */
-{
- return (res_nquery(get_static_res_state(), name, class, type, answer, anslen));
-}
-
-void
-res_send_setqhook(res_send_qhook hook) {
- _nres.qhook = hook;
-}
-
-void
-res_send_setrhook(res_send_rhook hook) {
- _nres.rhook = hook;
-}
-
-int
-res_isourserver(const struct sockaddr_in *inp) {
- return (res_ourserver_p(&_nres, (const struct sockaddr *)(const void *)inp));
-}
-
-int
-res_send(const u_char *buf, int buflen, u_char *ans, int anssiz) {
- return (res_nsend(get_static_res_state(), buf, buflen, ans, anssiz));
-}
-
-#ifdef _LIBRESOLV
-int
-res_sendsigned(const u_char *buf, int buflen, ns_tsig_key *key,
- u_char *ans, int anssiz)
-{
- return (res_nsendsigned(get_static_res_state(), buf, buflen, key, ans, anssiz));
-}
-#endif
-
-void
-res_close(void) {
- res_nclose(&_nres);
-}
-
-#ifdef _LIBRESOLV
-int
-res_update(ns_updrec *rrecp_in) {
- return (res_nupdate(get_static_res_state(), rrecp_in, NULL));
-}
-#endif
-
-int
-res_search(const char *name, /* domain name */
- int class, int type, /* class and type of query */
- u_char *answer, /* buffer to put answer */
- int anslen) /* size of answer */
-{
- return (res_nsearch(get_static_res_state(), name, class, type, answer, anslen));
-}
-
-int
-res_querydomain(const char *name,
- const char *domain,
- int class, int type, /* class and type of query */
- u_char *answer, /* buffer to put answer */
- int anslen) /* size of answer */
-{
- return (res_nquerydomain(get_static_res_state(), name, domain,
- class, type,
- answer, anslen));
-}
-
-int
-res_opt(int a, u_char *b, int c, int d)
-{
- return res_nopt(&_nres, a, b, c, d);
-}
-
-const char *
-hostalias(const char *name) {
- return NULL;
-}
-
-#ifdef ultrix
-int
-local_hostname_length(const char *hostname) {
- int len_host, len_domain;
-
- if (!*_nres.defdname)
- res_init();
- len_host = strlen(hostname);
- len_domain = strlen(_nres.defdname);
- if (len_host > len_domain &&
- !strcasecmp(hostname + len_host - len_domain, _nres.defdname) &&
- hostname[len_host - len_domain - 1] == '.')
- return (len_host - len_domain - 1);
- return (0);
-}
-#endif /*ultrix*/
-
-#endif
diff --git a/libc/dns/resolv/res_data.cpp b/libc/dns/resolv/res_data.cpp
new file mode 100644
index 0000000..22d9f7b
--- /dev/null
+++ b/libc/dns/resolv/res_data.cpp
@@ -0,0 +1,157 @@
+/* $NetBSD: res_data.c,v 1.8 2004/06/09 18:07:03 christos Exp $ */
+
+/*
+ * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (c) 1995-1999 by Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
+ * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "resolv_private.h"
+
+#include <pthread.h>
+
+extern "C" int res_ourserver_p(const res_state, const struct sockaddr*);
+extern "C" int __res_vinit(res_state, int);
+
+class GlobalStateAccessor {
+ public:
+ GlobalStateAccessor() {
+ pthread_mutex_lock(&mutex);
+ if (!initialized) {
+ init();
+ initialized = true;
+ }
+ }
+
+ ~GlobalStateAccessor() {
+ pthread_mutex_unlock(&mutex);
+ }
+
+ __res_state* get() {
+ return &state;
+ }
+
+ int init();
+
+ private:
+ static __res_state state;
+ static bool initialized;
+ static pthread_mutex_t mutex;
+};
+__res_state GlobalStateAccessor::state;
+bool GlobalStateAccessor::initialized = false;
+pthread_mutex_t GlobalStateAccessor::mutex = PTHREAD_MUTEX_INITIALIZER;
+
+int GlobalStateAccessor::init() {
+ // These three fields used to be statically initialized. This made
+ // it hard to use this code in a shared library. It is necessary,
+ // now that we're doing dynamic initialization here, that we preserve
+ // the old semantics: if an application modifies one of these three
+ // fields of _res before res_init() is called, res_init() will not
+ // alter them. Of course, if an application is setting them to
+ // _zero_ before calling res_init(), hoping to override what used
+ // to be the static default, we can't detect it and unexpected results
+ // will follow. Zero for any of these fields would make no sense,
+ // so one can safely assume that the applications were already getting
+ // unexpected results.
+ // g_nres.options is tricky since some apps were known to diddle the bits
+ // before res_init() was first called. We can't replicate that semantic
+ // with dynamic initialization (they may have turned bits off that are
+ // set in RES_DEFAULT). Our solution is to declare such applications
+ // "broken". They could fool us by setting RES_INIT but none do (yet).
+ if (!state.retrans) state.retrans = RES_TIMEOUT;
+ if (!state.retry) state.retry = 4;
+ if (!(state.options & RES_INIT)) state.options = RES_DEFAULT;
+
+ // This one used to initialize implicitly to zero, so unless the app
+ // has set it to something in particular, we can randomize it now.
+ if (!state.id) state.id = res_randomid();
+
+ return __res_vinit(&state, 1);
+}
+
+int res_init(void) {
+ GlobalStateAccessor gsa;
+ return gsa.init();
+}
+
+void p_query(const u_char* msg) {
+ fp_query(msg, stdout);
+}
+
+void fp_query(const u_char* msg, FILE* file) {
+ fp_nquery(msg, PACKETSZ, file);
+}
+
+void fp_nquery(const u_char* msg, int len, FILE* file) {
+ GlobalStateAccessor gsa;
+ res_pquery(gsa.get(), msg, len, file);
+}
+
+int
+res_mkquery(int op, const char* dname, int klass, int type, const u_char* data,
+ int datalen, const u_char* newrr_in, u_char* buf, int buflen) {
+ GlobalStateAccessor gsa;
+ return res_nmkquery(gsa.get(), op, dname, klass, type, data, datalen, newrr_in, buf, buflen);
+}
+
+int res_query(const char* name, int klass, int type, u_char* answer, int anslen) {
+ GlobalStateAccessor gsa;
+ return res_nquery(gsa.get(), name, klass, type, answer, anslen);
+}
+
+void res_send_setqhook(res_send_qhook hook) {
+ GlobalStateAccessor gsa;
+ gsa.get()->qhook = hook;
+}
+
+void res_send_setrhook(res_send_rhook hook) {
+ GlobalStateAccessor gsa;
+ gsa.get()->rhook = hook;
+}
+
+int res_isourserver(const struct sockaddr_in* inp) {
+ GlobalStateAccessor gsa;
+ return res_ourserver_p(gsa.get(), reinterpret_cast<const sockaddr*>(inp));
+}
+
+int res_send(const u_char* buf, int buflen, u_char* ans, int anssiz) {
+ GlobalStateAccessor gsa;
+ return res_nsend(gsa.get(), buf, buflen, ans, anssiz);
+}
+
+void res_close(void) {
+ GlobalStateAccessor gsa;
+ res_nclose(gsa.get());
+}
+
+int res_search(const char* name, int klass, int type, u_char* answer, int anslen) {
+ GlobalStateAccessor gsa;
+ return res_nsearch(gsa.get(), name, klass, type, answer, anslen);
+}
+
+int res_querydomain(const char* name, const char* domain, int klass, int type, u_char* answer,
+ int anslen) {
+ GlobalStateAccessor gsa;
+ return res_nquerydomain(gsa.get(), name, domain, klass, type, answer, anslen);
+}
+
+int res_opt(int a, u_char* b, int c, int d) {
+ GlobalStateAccessor gsa;
+ return res_nopt(gsa.get(), a, b, c, d);
+}
+
+const char* hostalias(const char* name) {
+ return NULL;
+}
diff --git a/libc/dns/resolv/res_debug.c b/libc/dns/resolv/res_debug.c
index 5f889cb..4fe7553 100644
--- a/libc/dns/resolv/res_debug.c
+++ b/libc/dns/resolv/res_debug.c
@@ -126,9 +126,27 @@
#include <strings.h>
#include <time.h>
-extern const char * const _res_opcodes[];
extern const char * const _res_sectioncodes[];
+__LIBC_HIDDEN__ const char* const _res_opcodes[] = {
+ "QUERY",
+ "IQUERY",
+ "CQUERYM",
+ "CQUERYU", /* experimental */
+ "NOTIFY", /* experimental */
+ "UPDATE",
+ "6",
+ "7",
+ "8",
+ "9",
+ "10",
+ "11",
+ "12",
+ "13",
+ "ZONEINIT",
+ "ZONEREF",
+};
+
#ifndef _LIBC
/*
* Print the current options.
diff --git a/libc/dns/resolv/res_state.c b/libc/dns/resolv/res_state.c
index 94124ff..d1f5c24 100644
--- a/libc/dns/resolv/res_state.c
+++ b/libc/dns/resolv/res_state.c
@@ -68,7 +68,7 @@
}
static void
-_res_static_done( res_static rs )
+_res_static_done(struct res_static* rs)
{
/* fortunately, there is nothing to do here, since the
* points in h_addr_ptrs and host_aliases should all
@@ -135,25 +135,6 @@
return rt;
}
-__LIBC_HIDDEN__
-struct __res_state _nres;
-
-#if 0
-struct resolv_cache*
-__get_res_cache(void)
-{
- _res_thread* rt = _res_thread_get();
-
- if (!rt)
- return NULL;
-
- if (!rt->_cache) {
- rt->_cache = _resolv_cache_create();
- }
- return rt->_cache;
-}
-#endif
-
int*
__get_h_errno(void)
{
@@ -177,9 +158,7 @@
/* nothing to do */
}
-res_static
-__res_get_static(void)
-{
+struct res_static* __res_get_static(void) {
_res_thread* rt = _res_thread_get();
return rt ? rt->_rstatic : NULL;