HW12/socket_wrapper.c
ubuntu201711081 d5f1fafd0b add base
2020-12-03 23:06:26 +00:00

71 lines
1.7 KiB
C

#include <signal.h>
#include <assert.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include "socket_wrapper.h"
int getBufferSizeFrom(int sock){
int buffer_sz;
socklen_t len = sizeof(buffer_sz);
if(getsockopt(sock,SOL_SOCKET,SO_SNDBUF,&buffer_sz,&len) < 0){
perror("failed to get sock buffer size: getsockopt");
buffer_sz = DEFAULT_BUF_SIZE;/*set to default*/
}
if(buffer_sz < MINIMUM_BUF_SIZE)
buffer_sz = MINIMUM_BUF_SIZE;
return buffer_sz;
}
static uint64_t timer_ticks = 0;
static void alarm_handler(int signum){
timer_ticks++;
}
void register_alarm(){
struct sigaction sigact;
sigact.sa_flags = SA_INTERRUPT;
sigemptyset(&sigact.sa_mask);
sigaddset(&sigact.sa_mask,SIGALRM);
sigact.sa_handler = alarm_handler;
sigaction(SIGALRM, &sigact ,NULL);
}
ssize_t timeout_recv(int fd,void * buf,size_t n,int timeout)
{
ssize_t ret;
uint64_t cur = timer_ticks;
int die_count = 0;
for(;;){
alarm(timeout);
ret = recv(fd,buf,n,0);
if (ret < 0 && errno == EINTR && cur != timer_ticks)
return -2;
alarm(0);
if (ret == 0){
usleep(100000);
die_count++;
if(die_count > timeout*10){
return -2;
}
}
else break;
}
return ret;
}
ssize_t recv_until_byte(int fd,void * buf, size_t n,int timeout){
ssize_t cur = 0;
uint8_t * b = buf;
while (cur < n)
{
ssize_t r = timeout_recv(fd,&b[cur],n-cur,timeout);
if (r < 0){
return r;
}
cur += r;
}
assert(cur == n);
return cur;
}