| From patchwork Sat Feb 4 12:19:01 2017 |
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| Subject: [pulseaudio-discuss] iochannel: don't use variable length array in |
| union |
| From: Tanu Kaskinen <tanuk@iki.fi> |
| X-Patchwork-Id: 136885 |
| Message-Id: <20170204121901.17428-1-tanuk@iki.fi> |
| To: pulseaudio-discuss@lists.freedesktop.org |
| Date: Sat, 4 Feb 2017 14:19:01 +0200 |
| |
| 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 |
| --- |
| Upstream-Status: Backport |
| Signed-off-by: Khem Raj <raj.khem@gmail.com> |
| |
| src/pulsecore/iochannel.c | 10 ++++++++-- |
| 1 file changed, 8 insertions(+), 2 deletions(-) |
| |
| diff --git a/src/pulsecore/iochannel.c b/src/pulsecore/iochannel.c |
| index 8ace297ff..897337522 100644 |
| --- a/src/pulsecore/iochannel.c |
| +++ b/src/pulsecore/iochannel.c |
| @@ -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; |