Read from socket

Question

I need to read from an AF_UNIX socket to a buffer using the function read from C, but I don\'t know the buffer size.

I think the best way is to read

Answer 1

One way to read an unknown amount from the socket while avoiding blocking could be to poll() a non-blocking socket for data.

E.g.

char buffer[1024];
int ptr = 0;
ssize_t rc;

struct pollfd fd = {
   .fd = sock,
   .events = POLLIN
};

poll(&fd, 1, 0); // Doesn't wait for data to arrive.
while ( fd.revents & POLLIN )
{
   rc = read(sock, buffer + ptr, sizeof(buffer) - ptr);

   if ( rc <= 0 )
      break;

   ptr += rc;
   poll(&fd, 1, 0);
}

printf("Read %d bytes from sock.\n", ptr);