From 4f99efb192590ec7263d1f88de99a03dbe469970 Mon Sep 17 00:00:00 2001 From: Jay Satiro Date: Wed, 15 Jan 2025 03:56:11 -0500 Subject: [PATCH] easy: allow connect-only handle reuse with easy_perform - Detach and disconnect an attached connection before performing. Prior to this change it was not possible to safely reuse an easy handle with an attached connection in a second call to curl_easy_perform. The only known case of this is a connect-only type handle where the connection was detached when curl_easy_perform returned, only to be reattached by either curl_easy_send/recv. This commit effectively reverts 2f8ecd5d and be82a360, the latter of which treated the reuse as an error. Prior to that change undefined behavior may occur in such a case. Bug: https://curl.se/mail/lib-2025-01/0044.html Reported-by: Aleksander Mazur Closes https://github.com/curl/curl/pull/16008 --- docs/libcurl/opts/CURLOPT_CONNECT_ONLY.md | 13 +++++------- lib/easy.c | 18 ++++++++++++----- tests/data/test696 | 24 ++++++++++++++++++++--- tests/libtest/lib556.c | 23 +++++++++++++++------- 4 files changed, 55 insertions(+), 23 deletions(-) diff --git a/docs/libcurl/opts/CURLOPT_CONNECT_ONLY.md b/docs/libcurl/opts/CURLOPT_CONNECT_ONLY.md index 90d17c7e9d..61cf2b802c 100644 --- a/docs/libcurl/opts/CURLOPT_CONNECT_ONLY.md +++ b/docs/libcurl/opts/CURLOPT_CONNECT_ONLY.md @@ -34,8 +34,8 @@ and then return. The option can be used to simply test a connection to a server, but is more useful when used with the CURLINFO_ACTIVESOCKET(3) option to -curl_easy_getinfo(3) as the library can set up the connection and then the -application can obtain the most recently used socket for special data +curl_easy_getinfo(3) as the library can set up the connection and then +the application can obtain the most recently used socket for special data transfers. Since 7.86.0, this option can be set to '2' and if HTTP or WebSocket are used, @@ -43,16 +43,13 @@ libcurl performs the request and reads all response headers before handing over control to the application. Transfers marked connect only do not reuse any existing connections and -connections marked connect only are not allowed to get reused. For this -reason, an easy handle cannot be reused for a second transfer when -CURLOPT_CONNECT_ONLY(3) is set, it must be closed with curl_easy_cleanup(3) -once the application is done with it. +connections marked connect only are not allowed to get reused. If the connect only transfer is done using the multi interface, the particular easy handle must remain added to the multi handle for as long as the application wants to use it. Once it has been removed with -curl_multi_remove_handle(3), curl_easy_send(3) and curl_easy_recv(3) do not -function. +curl_multi_remove_handle(3), curl_easy_send(3) and +curl_easy_recv(3) do not function. # DEFAULT diff --git a/lib/easy.c b/lib/easy.c index 657e007a94..1573a9d929 100644 --- a/lib/easy.c +++ b/lib/easy.c @@ -751,11 +751,6 @@ static CURLcode easy_perform(struct Curl_easy *data, bool events) if(!data) return CURLE_BAD_FUNCTION_ARGUMENT; - if(data->conn) { - failf(data, "cannot use again while associated with a connection"); - return CURLE_BAD_FUNCTION_ARGUMENT; - } - if(data->set.errorbuffer) /* clear this as early as possible */ data->set.errorbuffer[0] = 0; @@ -767,6 +762,19 @@ static CURLcode easy_perform(struct Curl_easy *data, bool events) return CURLE_FAILED_INIT; } + /* if the handle has a connection still attached (it is/was a connect-only + handle) then disconnect before performing */ + if(data->conn) { + struct connectdata *c; + curl_socket_t s; + Curl_detach_connection(data); + s = Curl_getconnectinfo(data, &c); + if((s != CURL_SOCKET_BAD) && c) { + Curl_cpool_disconnect(data, c, TRUE); + } + DEBUGASSERT(!data->conn); + } + if(data->multi_easy) multi = data->multi_easy; else { diff --git a/tests/data/test696 b/tests/data/test696 index 8b0bfd4309..1af5fc7a84 100644 --- a/tests/data/test696 +++ b/tests/data/test696 @@ -7,7 +7,7 @@ HTTP GET - + HTTP/1.1 200 OK swsclose Server: test-server/fake Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT @@ -38,15 +38,33 @@ http://%HOSTIP:%HTTPPORT # # Verify data after the test has been "shot" + +HTTP/1.1 200 OK swsclose +Server: test-server/fake +Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT +Content-Length: 6 +Connection: close + +-foo- +HTTP/1.1 200 OK swsclose +Server: test-server/fake +Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT +Content-Length: 6 +Connection: close + +-foo- + GET /556 HTTP/1.1 Host: ninja +GET /556 HTTP/1.1 +Host: ninja + -# 43 == CURLE_BAD_FUNCTION_ARGUMENT -43 +0 diff --git a/tests/libtest/lib556.c b/tests/libtest/lib556.c index 31818dc8a2..da9aea091e 100644 --- a/tests/libtest/lib556.c +++ b/tests/libtest/lib556.c @@ -41,6 +41,9 @@ CURLcode test(char *URL) { CURLcode res; CURL *curl; +#ifdef LIB696 + int transfers = 0; +#endif if(curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK) { fprintf(stderr, "curl_global_init() failed\n"); @@ -58,6 +61,10 @@ CURLcode test(char *URL) test_setopt(curl, CURLOPT_CONNECT_ONLY, 1L); test_setopt(curl, CURLOPT_VERBOSE, 1L); +#ifdef LIB696 +again: +#endif + res = curl_easy_perform(curl); if(!res) { @@ -87,8 +94,12 @@ CURLcode test(char *URL) if(nread) { /* send received stuff to stdout */ - if(!write(STDOUT_FILENO, buf, nread)) + if((size_t)write(STDOUT_FILENO, buf, nread) != nread) { + fprintf(stderr, "write() failed: errno %d (%s)\n", + errno, strerror(errno)); + res = TEST_ERR_FAILURE; break; + } } } while((res == CURLE_OK && nread) || (res == CURLE_AGAIN)); @@ -98,12 +109,10 @@ CURLcode test(char *URL) } #ifdef LIB696 - /* attempt to use the handle again */ - test_setopt(curl, CURLOPT_URL, URL); - test_setopt(curl, CURLOPT_CONNECT_ONLY, 1L); - test_setopt(curl, CURLOPT_VERBOSE, 1L); - - res = curl_easy_perform(curl); + ++transfers; + /* perform the transfer a second time */ + if(!res && transfers == 1) + goto again; #endif test_cleanup: -- 2.47.3