diff --git a/rust/chg/build.rs b/rust/chg/build.rs new file mode 100644 --- /dev/null +++ b/rust/chg/build.rs @@ -0,0 +1,8 @@ +extern crate cc; + +fn main() { + cc::Build::new() + .warnings(true) + .file("src/sendfds.c") + .compile("procutil"); +} diff --git a/rust/chg/src/sendfds.c b/rust/chg/src/sendfds.c new file mode 100644 --- /dev/null +++ b/rust/chg/src/sendfds.c @@ -0,0 +1,51 @@ +/* + * Utility to send fds via Unix domain socket + * + * Copyright 2011, 2018 Yuya Nishihara + * + * This software may be used and distributed according to the terms of the + * GNU General Public License version 2 or any later version. + */ + +#include +#include +#include +#include +#include + +#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); +}