1 /*************************************************************************  2     > File Name: pass_fd.c  3     > Author:Monica  4     > Mail:liling222@126.com   5     > Created Time: Mon 07 Jul 2014 09:52:49 PM CST  6  ************************************************************************/  7   8 #include <stdio.h>  9 #include <sys/types.h> 10 #include <sys/socket.h> 11 #include <strings.h> 12 #include <stdlib.h> 13 #include <unistd.h> 14 #include <signal.h> 15 #include <sys/stat.h> 16 #include <fcntl.h> 17 #include <string.h> 18  19 void my_handler(int signum) 20 { 21     wait(NULL); 22     exit(0); 23 } 24 void send_n(int fd_socket, int fd_to_send); 25 void recv_n(int fd_socket, int* fd_to_recv); 26  27 int main(int argc, char* argv[])    //exe  filename 28 { 29     int fd_socket[2]; 30     int fd_file; 31     if(socketpair(AF_LOCAL, SOCK_STREAM, 0, fd_socket) == -1) 32     { 33         perror("socketpair"); 34         exit(-1); 35     } 36     if(fork()>0)    //parent fd[0] 37     { 38         close(fd_socket[1]); 39         signal(SIGCHLD, my_handler); 40         fd_file = open(argv[1], O_RDONLY); 41         if(fd_file == -1) 42         { 43             perror("open"); 44             close(fd_socket[0]); 45             close(fd_socket[1]); 46             exit(-1); 47         } 48         send_n(fd_socket[0], fd_file); 49         printf("parent fd_file:%d\n", fd_file); 50         close(fd_file); 51         close(fd_socket[0]); 52         return; 53     } 54     else    //child fd[1] 55     { 56         int fd_to_recv; 57         char buf[1024]; 58         close(fd_socket[0]); 59         recv_n(fd_socket[1], &fd_to_recv); 60         printf("child recv fd:%d\n", fd_to_recv); 61         FILE* fp = fdopen(fd_to_recv, "r"); 62         while(bzero(buf, 1024), fgets(buf, 1024, fp) != NULL) 63         { 64             printf("%s", buf); 65         } 66         fclose(fp); 67         close(fd_to_recv); 68         close(fd_socket[1]); 69     } 70     return 0; 71 } 72 void send_n(int fd_socket, int fd_to_send) 73 { 74     struct msghdr send_msg; 75     struct iovec  bufs[1]; 76     struct cmsghdr *pcmsg; 77     char buffer[]="hello world"; 78     int cmsglen = CMSG_LEN(sizeof(int)); 79     send_msg.msg_name = NULL; 80     send_msg.msg_namelen = 0; 81     send_msg.msg_flags = 0; 82     bufs[0].iov_base = buffer; 83     bufs[0].iov_len = strlen(buffer); 84     send_msg.msg_iov = bufs; 85     send_msg.msg_iovlen = 1; 86     pcmsg = (struct cmsghdr*)calloc(1, cmsglen); 87     pcmsg->cmsg_len = cmsglen; 88     pcmsg->cmsg_level = SOL_SOCKET; 89     pcmsg->cmsg_type = SCM_RIGHTS; 90     *(int*)CMSG_DATA(pcmsg) = fd_to_send; 91     send_msg.msg_control = pcmsg; 92     send_msg.msg_controllen = cmsglen; 93     sendmsg(fd_socket, &send_msg, 0); 94 } 95  96 void recv_n(int fd_socket, int* fd_to_recv) 97 { 98     struct msghdr recv_msg; 99     struct iovec  bufs[1];100     struct cmsghdr*  pcmsg;101     char buffer[1024]="";102     int cmsglen = CMSG_LEN(sizeof(int));103     pcmsg = (struct cmsghdr*)calloc(1,cmsglen );104     bufs[0].iov_base = buffer;105     bufs[0].iov_len = 1024;106     recv_msg.msg_iov = bufs;107     recv_msg.msg_iovlen = 1;108     recv_msg.msg_control = pcmsg;109     recv_msg.msg_controllen = cmsglen;110     recvmsg(fd_socket, &recv_msg, 0);111     printf("buf:%s\n", buffer);112     *fd_to_recv = *(int*)CMSG_DATA(pcmsg);113 }