从read(2)开始：

EINTR  The call was interrupted by a signal before any data
          was read; see signal(7).

如果您修改代码使其看起来更像：

cont = 1;
while (1 && cont) {
    ret = read(sockfd, buf, sizeof(buf));
    if (ret < 0 && errno == EINTR)
        cont = arbitrary_function();
}

这让arbitrary_function()决定是否应该重试read(2)。

更新

您需要处理信号，以便从read(2)获得EINTR行为：

# include<unistd.h>

# include<stdio.h>

# include<stdlib.h>

# include<signal.h>

# include<errno.h>

int interrupted;

void handle_int(int num) {
  interrupted = 1;
}

int main(void){
  char buf[9001];
  struct sigaction int_handler = {.sa_handler=handle_int};
  sigaction(SIGINT,&int_handler,0);
  while(!interrupted){
    printf("interrupted: %d\n", interrupted);
    if(read(0,buf,sizeof(buf))<0){
      if(errno==EINTR){
        puts("eintr");
      }else{
        printf("%d\n",errno);
      }
      puts(".");
    }
  }
  puts("end");
  return 0;
}

给出输出：

$ ./foo
interrupted: 0
hello
interrupted: 0
^Ceintr
.
end

当您的进程收到信号时，read()将返回，errno的值将设置为EINTR。