Add selftests verifying the EOF and ECONNRESET behaviour of UNIX domain sockets (SOCK_STREAM and SOCK_DGRAM). The tests document Linux's semantics and clarify the long-standing differences with BSD.
Suggested-by: Kuniyuki Iwashima <[email protected]> Signed-off-by: Sunday Adelodun <[email protected]> --- tools/testing/selftests/net/unix/Makefile | 5 + .../selftests/net/unix/test_unix_connreset.c | 147 ++++++++++++++++++ 2 files changed, 152 insertions(+) create mode 100644 tools/testing/selftests/net/unix/Makefile create mode 100644 tools/testing/selftests/net/unix/test_unix_connreset.c diff --git a/tools/testing/selftests/net/unix/Makefile b/tools/testing/selftests/net/unix/Makefile new file mode 100644 index 000000000000..a52992ba23d9 --- /dev/null +++ b/tools/testing/selftests/net/unix/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 +TEST_GEN_PROGS := test_unix_connreset + +include ../../lib.mk + diff --git a/tools/testing/selftests/net/unix/test_unix_connreset.c b/tools/testing/selftests/net/unix/test_unix_connreset.c new file mode 100644 index 000000000000..a8720c7565cb --- /dev/null +++ b/tools/testing/selftests/net/unix/test_unix_connreset.c @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Selftest for UNIX socket close and ECONNRESET behaviour. + * + * This test verifies that: + * 1. SOCK_STREAM sockets return EOF when peer closes normally. + * 2. SOCK_STREAM sockets return ECONNRESET if peer closes with unread data. + * 3. SOCK_DGRAM sockets do not return ECONNRESET when peer closes, + * unlike BSD where this error is observed. + * + * These tests document the intended Linux behaviour, distinguishing it from BSD. + * + */ + +#define _GNU_SOURCE +#include <stdlib.h> +#include <string.h> +#include <fcntl.h> +#include <unistd.h> +#include <errno.h> +#include <sys/socket.h> +#include <sys/un.h> +#include "../../kselftest_harness.h" + +#define SOCK_PATH "/tmp/test_unix_connreset.sock" + +static void remove_socket_file(void) +{ + unlink(SOCK_PATH); +} + +/* Test 1: peer closes normally */ +TEST(stream_eof) +{ + int server, client, child; + struct sockaddr_un addr = {0}; + char buf[16] = {0}; + ssize_t n; + + server = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_GE(server, 0); + + addr.sun_family = AF_UNIX; + strcpy(addr.sun_path, SOCK_PATH); + remove_socket_file(); + + ASSERT_EQ(bind(server, (struct sockaddr *)&addr, sizeof(addr)), 0); + ASSERT_EQ(listen(server, 1), 0); + + client = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_GE(client, 0); + ASSERT_EQ(connect(client, (struct sockaddr *)&addr, sizeof(addr)), 0); + + child = accept(server, NULL, NULL); + ASSERT_GE(child, 0); + + /* Peer closes normally */ + close(child); + + n = recv(client, buf, sizeof(buf), 0); + EXPECT_EQ(n, 0); + TH_LOG("recv=%zd errno=%d (%s)", n, errno, strerror(errno)); + + close(client); + close(server); + remove_socket_file(); +} + +/* Test 2: peer closes with unread data */ +TEST(stream_reset_unread) +{ + int server, client, child; + struct sockaddr_un addr = {0}; + char buf[16] = {0}; + ssize_t n; + + server = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_GE(server, 0); + + addr.sun_family = AF_UNIX; + strcpy(addr.sun_path, SOCK_PATH); + remove_socket_file(); + + ASSERT_EQ(bind(server, (struct sockaddr *)&addr, sizeof(addr)), 0); + ASSERT_EQ(listen(server, 1), 0); + + client = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_GE(client, 0); + ASSERT_EQ(connect(client, (struct sockaddr *)&addr, sizeof(addr)), 0); + + child = accept(server, NULL, NULL); + ASSERT_GE(child, 0); + + /* Send data that will remain unread by client */ + send(client, "hello", 5, 0); + close(child); + + n = recv(client, buf, sizeof(buf), 0); + EXPECT_LT(n, 0); + EXPECT_EQ(errno, ECONNRESET); + TH_LOG("recv=%zd errno=%d (%s)", n, errno, strerror(errno)); + + close(client); + close(server); + remove_socket_file(); +} + +/* Test 3: SOCK_DGRAM peer close */ +TEST(dgram_reset) +{ + int server, client; + int flags; + struct sockaddr_un addr = {0}; + char buf[16] = {0}; + ssize_t n; + + server = socket(AF_UNIX, SOCK_DGRAM, 0); + ASSERT_GE(server, 0); + + addr.sun_family = AF_UNIX; + strcpy(addr.sun_path, SOCK_PATH); + remove_socket_file(); + + ASSERT_EQ(bind(server, (struct sockaddr *)&addr, sizeof(addr)), 0); + + client = socket(AF_UNIX, SOCK_DGRAM, 0); + ASSERT_GE(client, 0); + ASSERT_EQ(connect(client, (struct sockaddr *)&addr, sizeof(addr)), 0); + + send(client, "hello", 5, 0); + close(server); + + flags = fcntl(client, F_GETFL, 0); + fcntl(client, F_SETFL, flags | O_NONBLOCK); + + n = recv(client, buf, sizeof(buf), 0); + TH_LOG("recv=%zd errno=%d (%s)", n, errno, strerror(errno)); + /* Expect EAGAIN or EWOULDBLOCK because there is no datagram and peer is closed. */ + EXPECT_LT(n, 0); + EXPECT_TRUE(errno == EAGAIN); + + close(client); + remove_socket_file(); +} + +TEST_HARNESS_MAIN + -- 2.43.0
