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#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <assert.h>
#if EMSCRIPTEN
#include <emscripten.h>
#endif
#define EXPECTED_BYTES 5
int sockfd;
int not_always_data = 0;
void finish(int result) {
close(sockfd);
#if EMSCRIPTEN
REPORT_RESULT();
#endif
exit(result);
}
unsigned int get_all_buf(int sock, char* output, unsigned int maxsize) {
// select check for IO
fd_set sett;
FD_ZERO(&sett);
assert(select(64, &sett, NULL, NULL, NULL) == 0); // empty set
FD_SET(sock, &sett);
assert(select(0, &sett, NULL, NULL, NULL) == 0); // max FD to check is 0
assert(FD_ISSET(sock, &sett) == 0);
FD_SET(sock, &sett);
int select_says_yes = select(64, &sett, NULL, NULL, NULL);
// ioctl check for IO
int bytes;
if (ioctl(sock, FIONREAD, &bytes) || bytes == 0) {
not_always_data = 1;
printf("ioctl says 0, FD_ISSET says %ld\n", FD_ISSET(sock, &sett));
assert(FD_ISSET(sock, &sett) == 0);
return 0;
}
assert(FD_ISSET(sock, &sett));
assert(select_says_yes); // ioctl must agree with select
char buffer[1024];
int n;
unsigned int offset = 0;
while((errno = 0, (n = recv(sock, buffer, sizeof(buffer), 0))>0) ||
errno == EINTR) {
if(n > 0) {
if (((unsigned int) n)+offset > maxsize) {
fprintf(stderr, "too much data!");
finish(EXIT_FAILURE);
}
memcpy(output+offset, buffer, n);
offset += n;
}
}
if (n < 0 && errno != EAGAIN && errno != EWOULDBLOCK) {
fprintf(stderr, "error in get_all_buf! %d", errno);
finish(EXIT_FAILURE);
}
return offset;
}
void iter(void *arg) {
static char out[1024*2];
static int pos = 0;
fd_set fdr;
int res;
// make sure that sockfd is ready to read
FD_ZERO(&fdr);
FD_SET(sockfd, &fdr);
res = select(64, &fdr, NULL, NULL, NULL);
if (res == -1) {
perror("select failed");
finish(EXIT_FAILURE);
} else if (!FD_ISSET(sockfd, &fdr)) {
return;
}
// perform read write operations ...
int n = get_all_buf(sockfd, out+pos, 1024-pos);
if (n) printf("read! %d\n", n);
pos += n;
if (pos >= EXPECTED_BYTES) {
int i, sum = 0;
for (i=0; i < pos; i++) {
printf("%x\n", out[i]);
sum += out[i];
}
shutdown(sockfd, SHUT_RDWR);
close(sockfd);
printf("sum: %d\n", sum);
finish(sum);
}
}
void main() {
struct sockaddr_in addr;
int res;
sockfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sockfd == -1) {
perror("cannot create socket");
finish(EXIT_FAILURE);
}
fcntl(sockfd, F_SETFL, O_NONBLOCK);
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_port = htons(SOCKK);
if (inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr) != 1) {
perror("inet_pton failed");
finish(EXIT_FAILURE);
}
res = connect(sockfd, (struct sockaddr *)&addr, sizeof(addr));
if (res == -1 && errno != EINPROGRESS) {
perror("connect failed");
finish(EXIT_FAILURE);
}
#if EMSCRIPTEN
emscripten_set_main_loop(iter, 0, 0);
#else
while (1) iter(NULL);
#endif
}
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