Hi,
My code is launching a server with a port 0, so that it finds
any free port. Then after that, it records the port number used and a client is
launched that attaches to it. However, in restore, instead of recording the
actual port it landed on and used, it appears to basically do the bind again
with the port # of 0. As a result, my server is now on a different port, and my
client cannot connect properly. Here's some code that approximates the problem:
/* Includes */
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ipc.h>
#include <netinet/in.h>
#include <netdb.h>
int main() {
struct sockaddr_in server_addr;
int i, socket_fd;
unsigned int sockaddr_len = sizeof(struct sockaddr_in);
/* Typical socket setup */
socket_fd = socket(AF_INET, SOCK_STREAM, 0);
if (socket_fd < 0) {
fprintf(stderr, "ERROR: Unable to open socket\n");
return 1;
}
/* Setup for finding any free port */
memset(&server_addr, 0, sizeof(server_addr));
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(0);
/* Bind and listen for a new connection, return the connection through
* output parameter final_fd.
*/
server_addr.sin_addr.s_addr = INADDR_ANY;
if (bind(socket_fd, (struct sockaddr *)&server_addr,
sizeof(server_addr)) < 0) {
fprintf(stderr, "ERROR: Unable to bind socket\n");
return 1;
}
for (i = 0; i < 100; i++) {
/* Print the socket it is bound to. */
getsockname(socket_fd, (struct sockaddr *) &server_addr,
&sockaddr_len);
printf("Real socket is %u\n", ntohs(server_addr.sin_port));
sleep(3);
}
close(socket_fd);
} /* END main */
When it gets to the part about printing the "Real socket is %u", make a
checkpoint. You'll see that when you restart from that checkpoint you keep
getting different numbers.
Joshua Louie
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