On Fri, Sep 10, 2021 at 07:40:58PM +0200, Alexander Bluhm wrote:
> Hi,
>
> After converting syslogd messages to iov, UDP can use sendmsg(2)
> instead of snprintf().
>
> ok?
>
I have one question below, but the diff is ok by mvs@ if it is not
significant.
It is expected we could drop iov[6].iov_len bytes more from `msg' but
keep newline stuff when message size exceeds MAX_UDPMSG? The original
code has the different behaviour.
> bluhm
>
> Index: usr.sbin/syslogd/syslogd.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/syslogd/syslogd.c,v
> retrieving revision 1.269
> diff -u -p -r1.269 syslogd.c
> --- usr.sbin/syslogd/syslogd.c 10 Sep 2021 15:18:36 -0000 1.269
> +++ usr.sbin/syslogd/syslogd.c 10 Sep 2021 17:36:45 -0000
> @@ -1897,6 +1897,7 @@ void
> fprintlog(struct filed *f, int flags, char *msg)
> {
> struct iovec iov[IOVCNT], *v;
> + struct msghdr msghdr;
> int l, retryonce;
> char line[LOG_MAXLINE + 1], pribuf[13], greetings[500], repbuf[80];
> char ebuf[ERRBUFSIZE];
> @@ -2037,20 +2038,22 @@ fprintlog(struct filed *f, int flags, ch
>
> case F_FORWUDP:
> log_debug(" %s", f->f_un.f_forw.f_loghost);
> - l = snprintf(line, MINIMUM(MAX_UDPMSG + 1, sizeof(line)),
> - "%s%s%s%s%s%s%s", (char *)iov[0].iov_base,
> - (char *)iov[1].iov_base, (char *)iov[2].iov_base,
> - (char *)iov[3].iov_base, (char *)iov[4].iov_base,
> - (char *)iov[5].iov_base, (char *)iov[6].iov_base);
> - if (l < 0)
> - l = strlcpy(line, iov[5].iov_base, sizeof(line));
> - if (l >= sizeof(line))
> - l = sizeof(line) - 1;
> - if (l >= MAX_UDPMSG + 1)
> - l = MAX_UDPMSG;
> - if (sendto(f->f_file, line, l, 0,
> - (struct sockaddr *)&f->f_un.f_forw.f_addr,
> - f->f_un.f_forw.f_addr.ss_len) != l) {
> + l = iov[0].iov_len + iov[1].iov_len + iov[2].iov_len +
> + iov[3].iov_len + iov[4].iov_len + iov[5].iov_len +
> + iov[6].iov_len;
> + if (l > MAX_UDPMSG) {
> + l -= MAX_UDPMSG;
> + if (iov[5].iov_len > l)
> + iov[5].iov_len -= l;
> + else
> + iov[5].iov_len = 0;
> + }
> + memset(&msghdr, 0, sizeof(msghdr));
> + msghdr.msg_name = &f->f_un.f_forw.f_addr;
> + msghdr.msg_namelen = f->f_un.f_forw.f_addr.ss_len;
> + msghdr.msg_iov = iov;
> + msghdr.msg_iovlen = IOVCNT;
> + if (sendmsg(f->f_file, &msghdr, 0) == -1) {
> switch (errno) {
> case EADDRNOTAVAIL:
> case EHOSTDOWN:
> @@ -2063,7 +2066,7 @@ fprintlog(struct filed *f, int flags, ch
> break;
> default:
> f->f_type = F_UNUSED;
> - log_warn("sendto \"%s\"",
> + log_warn("sendmsg to \"%s\"",
> f->f_un.f_forw.f_loghost);
> break;
> }
>
