From 6765e6d9e6a32bb4fc666d744cb57e2d55d4e13b Mon Sep 17 00:00:00 2001 From: Romain Fliedel Date: Mon, 5 Nov 2018 11:01:19 +0100 Subject: ares: remove fd from multi fd set when ares is about to close the fd When using c-ares for asyn dns, the dns socket fd was silently closed by c-ares without curl being aware. curl would then 'realize' the fd has been removed at next call of Curl_resolver_getsock, and only then notify the CURLMOPT_SOCKETFUNCTION to remove fd from its poll set with CURL_POLL_REMOVE. At this point the fd is already closed. By using ares socket state callback (ARES_OPT_SOCK_STATE_CB), this patch allows curl to be notified that the fd is not longer needed for neither for write nor read. At this point by calling Curl_multi_closed we are able to notify multi with CURL_POLL_REMOVE before the fd is actually closed by ares. In asyn-ares.c Curl_resolver_duphandle we can't use ares_dup anymore since it does not allow passing a different sock_state_cb_data Closes #3238 --- lib/asyn-ares.c | 33 ++++++++++++++++++++++++++------- lib/asyn-thread.c | 7 ++++--- lib/asyn.h | 9 +++++---- lib/connect.c | 4 ++-- lib/easy.c | 3 ++- lib/multi.c | 8 ++++---- lib/multiif.h | 2 +- lib/url.c | 2 +- 8 files changed, 45 insertions(+), 23 deletions(-) diff --git a/lib/asyn-ares.c b/lib/asyn-ares.c index 5cfb2602d..6a49566c8 100644 --- a/lib/asyn-ares.c +++ b/lib/asyn-ares.c @@ -119,6 +119,17 @@ void Curl_resolver_global_cleanup(void) #endif } + +static void Curl_ares_sock_state_cb(void *data, ares_socket_t socket_fd, + int readable, int writable) +{ + struct Curl_easy *easy = data; + if(!readable && !writable) { + DEBUGASSERT(easy); + Curl_multi_closed(easy, socket_fd); + } +} + /* * Curl_resolver_init() * @@ -126,9 +137,14 @@ void Curl_resolver_global_cleanup(void) * URL-state specific environment ('resolver' member of the UrlState * structure). Fills the passed pointer by the initialized ares_channel. */ -CURLcode Curl_resolver_init(void **resolver) +CURLcode Curl_resolver_init(struct Curl_easy *easy, void **resolver) { - int status = ares_init((ares_channel*)resolver); + int status; + struct ares_options options; + int optmask = ARES_OPT_SOCK_STATE_CB; + options.sock_state_cb = Curl_ares_sock_state_cb; + options.sock_state_cb_data = easy; + status = ares_init_options((ares_channel*)resolver, &options, optmask); if(status != ARES_SUCCESS) { if(status == ARES_ENOMEM) return CURLE_OUT_OF_MEMORY; @@ -159,12 +175,15 @@ void Curl_resolver_cleanup(void *resolver) * environment ('resolver' member of the UrlState structure). Duplicates the * 'from' ares channel and passes the resulting channel to the 'to' pointer. */ -int Curl_resolver_duphandle(void **to, void *from) +CURLcode Curl_resolver_duphandle(struct Curl_easy *easy, void **to, void *from) { - /* Clone the ares channel for the new handle */ - if(ARES_SUCCESS != ares_dup((ares_channel*)to, (ares_channel)from)) - return CURLE_FAILED_INIT; - return CURLE_OK; + (void)from; + /* + * it would be better to call ares_dup instead, but right now + * it is not possible to set 'sock_state_cb_data' outside of + * ares_init_options + */ + return Curl_resolver_init(easy, to); } static void destroy_async_data(struct Curl_async *async); diff --git a/lib/asyn-thread.c b/lib/asyn-thread.c index 2a59294e5..4c8f88b14 100644 --- a/lib/asyn-thread.c +++ b/lib/asyn-thread.c @@ -108,8 +108,9 @@ void Curl_resolver_global_cleanup(void) * URL-state specific environment ('resolver' member of the UrlState * structure). */ -CURLcode Curl_resolver_init(void **resolver) +CURLcode Curl_resolver_init(struct Curl_easy *easy, void **resolver) { + (void)easy; *resolver = calloc(1, sizeof(struct resdata)); if(!*resolver) return CURLE_OUT_OF_MEMORY; @@ -132,10 +133,10 @@ void Curl_resolver_cleanup(void *resolver) * Called from curl_easy_duphandle() to duplicate resolver URL state-specific * environment ('resolver' member of the UrlState structure). */ -int Curl_resolver_duphandle(void **to, void *from) +CURLcode Curl_resolver_duphandle(struct Curl_easy *easy, void **to, void *from) { (void)from; - return Curl_resolver_init(to); + return Curl_resolver_init(easy, to); } static void destroy_async_data(struct Curl_async *); diff --git a/lib/asyn.h b/lib/asyn.h index 3adc3664a..43625bc3b 100644 --- a/lib/asyn.h +++ b/lib/asyn.h @@ -60,7 +60,7 @@ void Curl_resolver_global_cleanup(void); * Returning anything else than CURLE_OK fails curl_easy_init() with the * correspondent code. */ -CURLcode Curl_resolver_init(void **resolver); +CURLcode Curl_resolver_init(struct Curl_easy *easy, void **resolver); /* * Curl_resolver_cleanup() @@ -79,7 +79,8 @@ void Curl_resolver_cleanup(void *resolver); * pointer. Returning anything else than CURLE_OK causes failed * curl_easy_duphandle() call. */ -int Curl_resolver_duphandle(void **to, void *from); +CURLcode Curl_resolver_duphandle(struct Curl_easy *easy, void **to, + void *from); /* * Curl_resolver_cancel(). @@ -150,8 +151,8 @@ Curl_addrinfo *Curl_resolver_getaddrinfo(struct connectdata *conn, #define Curl_resolver_is_resolved(x,y) CURLE_COULDNT_RESOLVE_HOST #define Curl_resolver_wait_resolv(x,y) CURLE_COULDNT_RESOLVE_HOST #define Curl_resolver_getsock(x,y,z) 0 -#define Curl_resolver_duphandle(x,y) CURLE_OK -#define Curl_resolver_init(x) CURLE_OK +#define Curl_resolver_duphandle(x,y,z) CURLE_OK +#define Curl_resolver_init(x,y) CURLE_OK #define Curl_resolver_global_init() CURLE_OK #define Curl_resolver_global_cleanup() Curl_nop_stmt #define Curl_resolver_cleanup(x) Curl_nop_stmt diff --git a/lib/connect.c b/lib/connect.c index 41f220268..18645b9b7 100644 --- a/lib/connect.c +++ b/lib/connect.c @@ -1314,7 +1314,7 @@ int Curl_closesocket(struct connectdata *conn, conn->sock_accepted[SECONDARYSOCKET] = FALSE; else { int rc; - Curl_multi_closed(conn, sock); + Curl_multi_closed(conn->data, sock); Curl_set_in_callback(conn->data, true); rc = conn->fclosesocket(conn->closesocket_client, sock); Curl_set_in_callback(conn->data, false); @@ -1324,7 +1324,7 @@ int Curl_closesocket(struct connectdata *conn, if(conn) /* tell the multi-socket code about this */ - Curl_multi_closed(conn, sock); + Curl_multi_closed(conn->data, sock); sclose(sock); diff --git a/lib/easy.c b/lib/easy.c index 4de4e6522..d940b5d3e 100644 --- a/lib/easy.c +++ b/lib/easy.c @@ -966,7 +966,8 @@ struct Curl_easy *curl_easy_duphandle(struct Curl_easy *data) } /* Clone the resolver handle, if present, for the new handle */ - if(Curl_resolver_duphandle(&outcurl->state.resolver, + if(Curl_resolver_duphandle(outcurl, + &outcurl->state.resolver, data->state.resolver)) goto fail; diff --git a/lib/multi.c b/lib/multi.c index 0db2a9730..fbd389716 100644 --- a/lib/multi.c +++ b/lib/multi.c @@ -2466,11 +2466,11 @@ void Curl_updatesocket(struct Curl_easy *data) * socket again and it gets the same file descriptor number. */ -void Curl_multi_closed(struct connectdata *conn, curl_socket_t s) +void Curl_multi_closed(struct Curl_easy *data, curl_socket_t s) { - if(conn->data) { + if(data) { /* if there's still an easy handle associated with this connection */ - struct Curl_multi *multi = conn->data->multi; + struct Curl_multi *multi = data->multi; if(multi) { /* this is set if this connection is part of a handle that is added to a multi handle, and only then this is necessary */ @@ -2478,7 +2478,7 @@ void Curl_multi_closed(struct connectdata *conn, curl_socket_t s) if(entry) { if(multi->socket_cb) - multi->socket_cb(conn->data, s, CURL_POLL_REMOVE, + multi->socket_cb(data, s, CURL_POLL_REMOVE, multi->socket_userp, entry->socketp); diff --git a/lib/multiif.h b/lib/multiif.h index c8fb5ca0d..c50063dae 100644 --- a/lib/multiif.h +++ b/lib/multiif.h @@ -89,7 +89,7 @@ void Curl_multi_connchanged(struct Curl_multi *multi); * socket again and it gets the same file descriptor number. */ -void Curl_multi_closed(struct connectdata *conn, curl_socket_t s); +void Curl_multi_closed(struct Curl_easy *data, curl_socket_t s); /* * Add a handle and move it into PERFORM state at once. For pushed streams. diff --git a/lib/url.c b/lib/url.c index 6118177d6..0ebf0a07a 100644 --- a/lib/url.c +++ b/lib/url.c @@ -570,7 +570,7 @@ CURLcode Curl_open(struct Curl_easy **curl) data->magic = CURLEASY_MAGIC_NUMBER; - result = Curl_resolver_init(&data->state.resolver); + result = Curl_resolver_init(data, &data->state.resolver); if(result) { DEBUGF(fprintf(stderr, "Error: resolver_init failed\n")); free(data); -- cgit v1.2.1