68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <string.h>
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#include <arpa/inet.h>
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#include <stdio.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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typedef struct sockaddr_in SockAddr_in;
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typedef struct sockaddr SockAddr;
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SockAddr_in addr;
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socklen_t addr_size;
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int socket_fd;
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void handle_error(char *txt)
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{
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perror(txt);
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exit(-1);
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}
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void receive_urgent()
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{
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double dd;
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if (recvfrom(socket_fd, &dd, sizeof(double), MSG_OOB, (SockAddr *)&addr, &addr_size) == -1)
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handle_error("recvfrom urgent");
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printf("dd: %f\n", dd);
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signal(SIGURG, receive_urgent);
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}
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int main()
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{
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if ((socket_fd = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
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handle_error("socket");
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addr_size = sizeof(SockAddr_in);
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memset(&addr, 0, addr_size);
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addr.sin_port = htons(4040);
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addr.sin_family = PF_INET;
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addr.sin_addr.s_addr = htonl(INADDR_ANY);
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// inet_pton(AF_INET, "127.0.0.1", &(addr.sin_addr.s_addr));
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if (bind(socket_fd, (SockAddr *)&addr, addr_size) == -1)
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handle_error("bind");
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double dd;
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for (;;)
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{
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fcntl(socket_fd, F_SETOWN, getpid());
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signal(SIGURG, receive_urgent);
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int bytes = recvfrom(socket_fd, &dd, sizeof(double), 0, (SockAddr *)&addr, &addr_size);
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if (bytes == -1)
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handle_error("recvfrom");
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if (bytes == 0)
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{
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printf("EOF\n");
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}
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printf("dd: %f\n", dd);
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}
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if (close(socket_fd) == -1)
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handle_error("close");
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return 0;
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}
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