iochannel: don't use variable length array in union

Clang didn't like the variable length array:

pulsecore/iochannel.c:358:17: error: fields must have a constant size:
'variable length array in structure' extension will never be supported
        uint8_t data[CMSG_SPACE(sizeof(int) * nfd)];
                ^

Commit 451d1d6762 introduced the variable length array in order to have
the correct value in msg_controllen. This patch reverts that commit and
uses a different way to achieve the same goal.

BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=99458
This commit is contained in:
Tanu Kaskinen 2017-02-04 14:19:01 +02:00
parent 0cb72beace
commit 18ec0fe53e

View file

@ -355,7 +355,7 @@ ssize_t pa_iochannel_write_with_fds(pa_iochannel*io, const void*data, size_t l,
struct iovec iov;
union {
struct cmsghdr hdr;
uint8_t data[CMSG_SPACE(sizeof(int) * nfd)];
uint8_t data[CMSG_SPACE(sizeof(int) * MAX_ANCIL_DATA_FDS)];
} cmsg;
pa_assert(io);
@ -382,7 +382,13 @@ ssize_t pa_iochannel_write_with_fds(pa_iochannel*io, const void*data, size_t l,
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
mh.msg_control = &cmsg;
mh.msg_controllen = sizeof(cmsg);
/* If we followed the example on the cmsg man page, we'd use
* sizeof(cmsg.data) here, but if nfd < MAX_ANCIL_DATA_FDS, then the data
* buffer is larger than needed, and the kernel doesn't like it if we set
* msg_controllen to a larger than necessary value. The commit message for
* commit 451d1d6762 contains a longer explanation. */
mh.msg_controllen = CMSG_SPACE(sizeof(int) * nfd);
if ((r = sendmsg(io->ofd, &mh, MSG_NOSIGNAL)) >= 0) {
io->writable = io->hungup = false;