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https://github.com/NVIDIA/cuda-samples.git
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5443602d89
Release 13.4 of the CUDA Samples supported by CUDA Toolkit 13.4. See Changelog for more information.
111 lines
4.0 KiB
C
111 lines
4.0 KiB
C
/* Copyright (c) 2026, NVIDIA CORPORATION. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of NVIDIA CORPORATION nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
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* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* POSIX helpers used by the cross-process demos in dmabufInterop.cu:
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* - sendFd / recvFd: transport a file descriptor between two processes
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* over a UNIX domain socket via the SCM_RIGHTS control message.
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* - reapCrossProcessChild: waitpid() wrapper that returns 0 iff the child
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* exited cleanly with status 0.
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*
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* These are POSIX-only (no CUDA code) and are separated out so that
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* dmabufInterop.cu stays focused on the CUDA dma-buf export/import flow.
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*/
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#ifndef DMABUF_INTEROP_HELPERS_H
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#define DMABUF_INTEROP_HELPERS_H
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#include <stdio.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <sys/un.h>
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#include <sys/wait.h>
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#include <unistd.h>
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/* Send a file descriptor over a UNIX domain socket using SCM_RIGHTS. */
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static inline void sendFd(int sock, int fd)
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{
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struct msghdr msg = {};
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char dummy = 'F';
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struct iovec iov = { &dummy, 1 };
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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char cbuf[CMSG_SPACE(sizeof(int))] = {};
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msg.msg_control = cbuf;
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msg.msg_controllen = sizeof(cbuf);
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struct cmsghdr *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));
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memcpy(CMSG_DATA(cmsg), &fd, sizeof(int));
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(void)sendmsg(sock, &msg, 0);
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}
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/* Receive a file descriptor from a UNIX domain socket. Returns -1 if no
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* valid single-fd SCM_RIGHTS control message was received. */
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static inline int recvFd(int sock)
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{
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struct msghdr msg = {};
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char dummy = 0;
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struct iovec iov = { &dummy, 1 };
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msg.msg_iov = &iov;
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msg.msg_iovlen = 1;
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char cbuf[CMSG_SPACE(sizeof(int))] = {};
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msg.msg_control = cbuf;
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msg.msg_controllen = sizeof(cbuf);
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(void)recvmsg(sock, &msg, 0);
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struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
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/* Validate that recvmsg actually delivered a single-fd SCM_RIGHTS control
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* message before dereferencing -- a truncated or absent ancillary buffer
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* would otherwise crash on the memcpy below. */
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if (cmsg == NULL || cmsg->cmsg_len != CMSG_LEN(sizeof(int))) return -1;
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int fd = -1;
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memcpy(&fd, CMSG_DATA(cmsg), sizeof(int));
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return fd;
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}
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/* Wait for a child process to exit and return 0 iff it exited cleanly with
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* status 0. */
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static inline int reapCrossProcessChild(pid_t pid)
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{
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int status = 0;
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if (waitpid(pid, &status, 0) < 0) {
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perror("waitpid");
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return -1;
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}
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return (WIFEXITED(status) && WEXITSTATUS(status) == 0) ? 0 : -1;
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}
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#endif /* DMABUF_INTEROP_HELPERS_H */
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