Here v->iov_len has been assigned the return value from snprintf.

Checking if it is > 0 doesn't make sense, because snprintf returns
how much space is needed if the buffer is too small. Instead, check
if the return value was greater than the buffer size, and truncate
the message if it was too long.

It isn't clear if snprintf can return a negative value in the case
of an error - I don't believe it can. If it can, then testing
v->iov_len won't help 'cos it is a size_t, not an ssize_t.

Also, as clang points out, we must always increment v here, because
later code depends on the message being in iov[5].
This commit is contained in:
David Malone 2011-01-19 17:17:37 +00:00
parent 7a93bf9a69
commit 98d1f19ba2
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=217589

View File

@ -1093,8 +1093,9 @@ fprintlog(struct filed *f, int flags, const char *msg)
v->iov_len = snprintf(greetings, sizeof greetings,
"\r\n\7Message from syslogd@%s at %.24s ...\r\n",
f->f_prevhost, f->f_lasttime);
if (v->iov_len > 0)
v++;
if (v->iov_len >= sizeof greetings)
v->iov_len = sizeof greetings - 1;
v++;
v->iov_base = nul;
v->iov_len = 0;
v++;