sendfds.c
51 lines
| 1.3 KiB
| text/x-c
|
CLexer
Yuya Nishihara
|
r40005 | /* | ||
| * Utility to send fds via Unix domain socket | ||||
| * | ||||
| * Copyright 2011, 2018 Yuya Nishihara <yuya@tcha.org> | ||||
| * | ||||
| * This software may be used and distributed according to the terms of the | ||||
| * GNU General Public License version 2 or any later version. | ||||
| */ | ||||
| #include <errno.h> | ||||
| #include <stdlib.h> | ||||
| #include <string.h> | ||||
| #include <sys/socket.h> | ||||
| #include <sys/types.h> | ||||
| #define MAX_FD_LEN 10 | ||||
| /* | ||||
| * Sends the given fds with 1-byte dummy payload. | ||||
| * | ||||
| * Returns the number of bytes sent on success, -1 on error and errno is set | ||||
| * appropriately. | ||||
| */ | ||||
| ssize_t sendfds(int sockfd, const int *fds, size_t fdlen) | ||||
| { | ||||
| char dummy[1] = {0}; | ||||
| struct iovec iov = {dummy, sizeof(dummy)}; | ||||
| char fdbuf[CMSG_SPACE(sizeof(fds[0]) * MAX_FD_LEN)]; | ||||
| struct msghdr msgh; | ||||
| struct cmsghdr *cmsg; | ||||
| /* just use a fixed-size buffer since we'll never send tons of fds */ | ||||
| if (fdlen > MAX_FD_LEN) { | ||||
| errno = EINVAL; | ||||
| return -1; | ||||
| } | ||||
| memset(&msgh, 0, sizeof(msgh)); | ||||
| msgh.msg_iov = &iov; | ||||
| msgh.msg_iovlen = 1; | ||||
| msgh.msg_control = fdbuf; | ||||
| msgh.msg_controllen = CMSG_SPACE(sizeof(fds[0]) * fdlen); | ||||
| cmsg = CMSG_FIRSTHDR(&msgh); | ||||
| cmsg->cmsg_level = SOL_SOCKET; | ||||
| cmsg->cmsg_type = SCM_RIGHTS; | ||||
| cmsg->cmsg_len = CMSG_LEN(sizeof(fds[0]) * fdlen); | ||||
| memcpy(CMSG_DATA(cmsg), fds, sizeof(fds[0]) * fdlen); | ||||
| msgh.msg_controllen = cmsg->cmsg_len; | ||||
| return sendmsg(sockfd, &msgh, 0); | ||||
| } | ||||