ipref3 dll for windows - windows

Question

I try to build ipref3.dll for windows
I found How to compile iperf3 for Windows
Built it but i got only iperf3.exe and libiperf.a
I found, how create dll manual
gcc -s -shared -o iperf3.dll units.o timer.o tcp_window_size.o tcp_info.o net.o iperf_util.o iperf_sctp.o iperf_udp.o iperf_tcp.o iperf_server_api.o iperf_locale.o iperf_client_api.o iperf_error.o iperf_api.o cjson.o -Wl,--enable-auto-import,--export-all-symbols,--subsystem,windows
after i found how need to initialize
HMODULE h = LoadLibrary(TEXT("cygwin1.dll"));
PFN_CYGWIN_DLL_INIT init = (PFN_CYGWIN_DLL_INIT)GetProcAddress(h, "cygwin_dll_init");
init();
Now i can load dll and make initialization but when i start test iperf_run_client application is crashed
Unhandled exception at 0x611537C0 (cygwin1.dll) in iprerf-server.exe:
0xC0000005: Access violation reading location 0x00740000.
How can solve this problem?
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <WinSock2.h>
//#include <unistd.h>
#include <string.h>
//#include <sysexits.h>
#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif
#include "iperf_api.h"
#ifdef WIN64
#pragma comment(lib, "iperf3_64.lib")
#else
#pragma comment(lib, "iperf3.lib")
#endif
#pragma comment(lib, "ws2_32.lib")
typedef void *register_frame();
typedef int *hello_f();
typedef int(*PFN_HELLO)();
typedef void(*PFN_CYGWIN_DLL_INIT)();
#pragma pack(push, 1)
int main(int argc, char** argv)
{
WSADATA wsaData;
int wsaErr = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (wsaErr != 0) {
printf("WSAStartup failed with error: %d\n", wsaErr);
return 1;
}
//PFN_HELLO fnHello;
HMODULE /*hLib, */h = LoadLibrary(TEXT("cygwin1.dll"));
PFN_CYGWIN_DLL_INIT init = (PFN_CYGWIN_DLL_INIT)GetProcAddress(h, "cygwin_dll_init");
init();
char* argv0;
char* host;
int port;
struct iperf_test *test;
argv0 = strrchr(argv[0], '/');
if (argv0 != (char*)0)
++argv0;
else
argv0 = argv[0];
if (argc != 3) {
fprintf(stderr, "usage: %s [host] [port]\n", argv0);
exit(EXIT_FAILURE);
}
host = argv[1];
port = atoi(argv[2]);
test = iperf_new_test();
if (test == NULL) {
fprintf(stderr, "%s: failed to create test\n", argv0);
exit(EXIT_FAILURE);
}
iperf_defaults(test);
iperf_set_verbose(test, 1);
iperf_set_test_role(test, 'c');
iperf_set_test_server_hostname(test, host);
iperf_set_test_server_port(test, port);
/* iperf_set_test_reverse( test, 1 ); */
iperf_set_test_omit(test, 3);
iperf_set_test_duration(test, 5);
iperf_set_test_reporter_interval(test, 1);
iperf_set_test_stats_interval(test, 1);
/* iperf_set_test_json_output( test, 1 ); */
if (iperf_run_client(test) < 0) {
fprintf(stderr, "%s: error - %s\n", argv0, iperf_strerror(i_errno));
exit(EXIT_FAILURE);
}
if (iperf_get_test_json_output_string(test)) {
fprintf(iperf_get_test_outfile(test), "%zd bytes of JSON emitted\n",
strlen(iperf_get_test_json_output_string(test)));
}
iperf_free_test(test);
exit(EXIT_SUCCESS);
}

Answer 1

The reason why the shared lib is not built is:
libtool: warning: undefined symbols not allowed in x86_64-unknown-cygwin
shared libraries; building static only
the easy way to bypass it, in a clean build is to use:
$ make libiperf_la_LIBADD="-no-undefined"
The build will include the shared libray and the import library
$ find . -name "*dll*"
./src/.libs/cygiperf-0.dll
./src/.libs/libiperf.dll.a
For what I see to make a build on cygwin is also needed to remove a definition
in src/iperf_config.h after running configure
/* #define HAVE_SETPROCESSAFFINITYMASK 1 */
PS #1: iperf-2.0.5-1 is available as cygwin package
PS #2: your code is Windows-like while Cygwin is a Unix-like system, you can not mix them

Answer 2

I found solution
1) It need to create addition dll: my_crt0.dll
#include <sys/cygwin.h>
#include <stdlib.h>
typedef int (*MainFunc) (int argc, char *argv[], char **env);
void my_crt0 (MainFunc f)
{
cygwin_crt0(f);
}
gcc -c my_crt0.c
gcc -o my_crt0.dll my_crt0.o -s -shared -Wl,--subsystem,windows,--enable-auto-import,--export-all-symbols,--out-implib,my_crt0.lib
2) Modify main code
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <WinSock2.h>
#include <string.h>
#include "iperf_api.h"
#pragma comment(lib, "iperf3.lib")
#pragma comment(lib, "ws2_32.lib")
typedef int(*MainFunc) (int argc, char *argv[], char **env);
typedef void(*my_crt0)(MainFunc f);
int main2(int argc, char** argv, char **env)
{
char* argv0;
char* host;
int port;
struct iperf_test *test;
host = (char*)"127.0.0.1";
port = 4000;
test = iperf_new_test();
if (test == NULL) {
exit(EXIT_FAILURE);
}
iperf_defaults(test);
iperf_set_verbose(test, 1);
iperf_set_test_role(test, 'c');
iperf_set_test_server_hostname(test, host);
iperf_set_test_server_port(test, port);
/* iperf_set_test_reverse( test, 1 ); */
iperf_set_test_omit(test, 3);
iperf_set_test_duration(test, 5);
iperf_set_test_reporter_interval(test, 1);
iperf_set_test_stats_interval(test, 1);
/* iperf_set_test_json_output( test, 1 ); */
iperf_strerror(0);
if (iperf_run_client(test) < 0) {
fprintf(stderr, "%s: error - %s\n", argv0, iperf_strerror(i_errno));
exit(EXIT_FAILURE);
}
if (iperf_get_test_json_output_string(test)) {
fprintf(iperf_get_test_outfile(test), "%zd bytes of JSON emitted\n",
strlen(iperf_get_test_json_output_string(test)));
}
iperf_free_test(test);
exit(EXIT_SUCCESS);
return 1;
}
int main(int argc, char** argv)
{
WSADATA wsaData;
int wsaErr = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (wsaErr != 0) {
printf("WSAStartup failed with error: %d\n", wsaErr);
return 1;
}
{
HMODULE /*hLib, */h = LoadLibrary(TEXT("my_crt0.dll"));
my_crt0 init = (my_crt0)GetProcAddress(h, "my_crt0");
init(main2);
}
exit(EXIT_SUCCESS);
}
Now it compiled and worked to VS 2015