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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <sys/ioctl.h>
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#include <emscripten.h>
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#include "test_sockets_msg.h"
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#define MESSAGE "0123456789"
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void finish(int result) {
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void main_loop(void *arg) {
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static int readPos = 0;
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static int writePos = 0;
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ssize_t transferAmount;
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// writing 10 bytes to the server
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// since the socket in the read file descriptors has no available data,
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// select should tell us 0 handles are ready
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FD_SET(sockfd, &sett);
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selectRes = select(64, &sett, NULL, NULL, NULL);
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printf("case 0: read select != 0 (%d)\n", selectRes);
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// the socket in the write file descriptors has to result in either a 0 or 1
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// the connection either is setting up or is established and writing is possible
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FD_SET(sockfd, &sett);
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selectRes = select(64, NULL, &sett, NULL, NULL);
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if (selectRes == -1) {
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printf("case 0: write select == -1\n");
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} else if (selectRes == 0) {
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transferAmount = do_msg_write(sockfd, &writemsg, writePos, 1, NULL, 0);
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if (transferAmount != -1) writePos += transferAmount;
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// after 10 bytes switch to next state
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if (writePos >= writemsg.length) {
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// wait until we can read one byte to make sure the server
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// has sent the data and then closed the connection
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FD_SET(sockfd, &sett);
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selectRes = select(64, &sett, NULL, NULL, NULL);
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if (selectRes == -1) {
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printf("case 1: read selectRes == -1\n");
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} else if (selectRes == 0) {
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transferAmount = do_msg_read(sockfd, &readmsg, readPos, 1, NULL, NULL);
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if (transferAmount == 0) {
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perror("server closed");
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} else if (transferAmount != -1) {
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readPos += transferAmount;
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// if successfully reading 1 byte, switch to next state
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// calling select with the socket in the write file descriptors should
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// succeed, but the socket should not set in the set.
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FD_SET(sockfd, &sett);
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selectRes = select(64, NULL, &sett, NULL, NULL);
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if (selectRes != 0 || FD_ISSET(sockfd, &sett)) {
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printf("case 2: write selectRes != 0 || FD_ISSET(sockfd, &sett)\n");
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finish(EXIT_FAILURE);
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// calling select with the socket in the read file descriptors
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// has to succeed because there is still data in the inQueue
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FD_SET(sockfd, &sett);
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selectRes = select(64, &sett, NULL, NULL, NULL);
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if (selectRes != 1) {
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printf("case 2: read selectRes != 1\n");
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finish(EXIT_FAILURE);
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} else if (selectRes == 0) {
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// read a single byte
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transferAmount = do_msg_read(sockfd, &readmsg, readPos, 1, NULL, NULL);
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if (transferAmount == 0) {
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perror("server closed");
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finish(EXIT_FAILURE);
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} else if (transferAmount != -1) {
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readPos += transferAmount;
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// with 10 bytes read the inQueue is empty => switch state
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if (readPos >= readmsg.length) {
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// calling select with the socket in the read file descriptors
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FD_SET(sockfd, &sett);
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selectRes = select(64, &sett, NULL, NULL, NULL);
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if (selectRes != 1) {
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printf("case 3: read selectRes != 1\n");
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finish(EXIT_FAILURE);
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// but recv should return 0 signaling the remote
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// end has closed the connection.
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transferAmount = do_msg_read(sockfd, &readmsg, readPos, 0, NULL, NULL);
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if (transferAmount) {
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printf("case 3: read != 0\n");
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finish(EXIT_FAILURE);
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// report back success, the 266 is just an arbitrary value without
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printf("Impossible state!\n");
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finish(EXIT_FAILURE);
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// This test checks for an intended asymmetry in the behavior of the select function.
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// Scenario: the client sends data to the server. After 10 received bytes the
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// server sends 10 bytes on its own and immediately afterwards closes the connection.
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// This mimics a typical connect-request-response-disconnect situation.
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// After the server closed the connection select calls with the socket in the write file
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// descriptors have to fail as the tcp connection is already down and there is no way
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// anymore to send data.
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// Select calls with the socket in the read file descriptor list still have to succeed
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// as there are still 10 bytes to read from the inQueue. So, for the same socket the
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// select call behaves differently depending on whether the socket is listed in the
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// read or write file descriptors.
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struct sockaddr_in addr;
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memset(&readmsg, 0, sizeof(msg_t));
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memset(&writemsg, 0, sizeof(msg_t));
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writemsg.length = strlen(MESSAGE) + 1;
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writemsg.buffer = malloc(writemsg.length);
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strncpy(writemsg.buffer, MESSAGE, writemsg.length);
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sockfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
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perror("cannot create socket");
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finish(EXIT_FAILURE);
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fcntl(sockfd, F_SETFL, O_NONBLOCK);
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memset(&addr, 0, sizeof(addr));
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addr.sin_family = AF_INET;
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addr.sin_port = htons(SOCKK);
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if (inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr) != 1) {
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perror("inet_pton failed");
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finish(EXIT_FAILURE);
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// This call should succeed (even if the server port is closed)
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res = connect(sockfd, (struct sockaddr *)&addr, sizeof(addr));
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if (res == -1 && errno != EINPROGRESS) {
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perror("connect failed");
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finish(EXIT_FAILURE);
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emscripten_set_main_loop(main_loop, 0, 0);
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while (1) main_loop(NULL);
added
removed
tests/sockets/test_sockets_select_server_closes_connection_client_rw.c
