#include "transfd_shm.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <stddef.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <errno.h>
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int sendfd(int conn, int fd[], int fds){
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if (fds <= 0) return -1;
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struct msghdr msg = {};
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static char dummy = 'x';
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struct iovec iov = {&dummy, sizeof(dummy)};
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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struct cmsghdr* cmsg;
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const unsigned control_len = CMSG_SPACE(sizeof(int) * fds);
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char* control_buffer = (char*)malloc(control_len);
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msg.msg_control = control_buffer;
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msg.msg_controllen = control_len;
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cmsg = CMSG_FIRSTHDR(&msg);
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cmsg->cmsg_level = SOL_SOCKET;
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cmsg->cmsg_type = SCM_RIGHTS;
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cmsg->cmsg_len = CMSG_LEN(sizeof(int) * fds);
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memcpy(CMSG_DATA(cmsg), fd, sizeof(int) * fds);
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int ret = sendmsg(conn, &msg, MSG_NOSIGNAL);
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free(control_buffer);
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if (ret == -1){
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printf("sendmsg error %d -> %s\n", errno, strerror(errno));
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if (errno == EPIPE || errno == ECONNRESET || errno == ENOTCONN)
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return 0;
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return -1;
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}
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return ret;
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}
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int recvfd(int conn, int fd[], int fds){
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char data;
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struct msghdr msg = {};
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struct iovec iov = {&data, 1};
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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struct cmsghdr *cmsgp;
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const size_t control_len = CMSG_SPACE(sizeof(int) * 16);
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char control_buffer[control_len];
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msg.msg_control = control_buffer;
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msg.msg_controllen = sizeof(control_buffer);
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int ret = recvmsg(conn, &msg, MSG_CMSG_CLOEXEC);
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if (ret == -1){
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printf("recvmsg failed %d -> %s\n", errno, strerror(errno));
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if (errno == ECONNRESET)
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return 0;
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return -1;
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} else if (ret == 0){
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return 0;
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}
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int* wire_fds = NULL;
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unsigned wire_fds_len = 0;
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if (msg.msg_controllen > 0){
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struct cmsghdr* cmsg;
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for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
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const unsigned payload_len = cmsg->cmsg_len - CMSG_LEN(0);
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if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
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wire_fds = (int*)CMSG_DATA(cmsg);
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wire_fds_len = payload_len / sizeof(int);
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}
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}
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}
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const unsigned count = wire_fds_len > fds ? fds : wire_fds_len;
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for (unsigned i = 0; i < count; i++){
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fd[i] = wire_fds[i];
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}
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return wire_fds_len;
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}
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