uvms/pkgs/ch-proxy/sendfd.c
2026-01-22 14:29:45 +02:00

38 lines
976 B
C

#include "sendfd.h"
#include "sys/socket.h" /* cmsghdr */
#include "stdio.h" /* perror */
ssize_t send_fd(int dst_fd, int fd, const struct iovec *iov) {
struct msghdr msg = { 0 };
/* openssh expects to receive a dummy length=1 iovec? */
char ch = 0;
struct iovec vecDefault = { 0 };
vecDefault.iov_base = &ch;
vecDefault.iov_len = 1;
msg.msg_iov = iov == NULL ? &vecDefault : iov;
msg.msg_iovlen = 1;
union {
struct cmsghdr align;
char buf[CMSG_SPACE(sizeof(int))];
} u;
msg.msg_control = u.buf;
msg.msg_controllen = sizeof(u.buf);
struct cmsghdr *cmptr;
cmptr = CMSG_FIRSTHDR(&msg);
if (cmptr == NULL) {
perror("ch-proxy/send_fd/CMSG_FIRSTHDR: failed to initialize msg_control\n");
}
cmptr->cmsg_len = CMSG_LEN(sizeof(int));
cmptr->cmsg_level = SOL_SOCKET;
cmptr->cmsg_type = SCM_RIGHTS;
*((int*) CMSG_DATA(cmptr)) = fd;
return (sendmsg(dst_fd, &msg, 0));
}