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Linux epoll: Allow passing of any negative timeout value to epoll_wait

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Linux epoll allow passing of any negative timeout value to epoll_wait()
to cause unbound blocking

Reviewed by:	emaste
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D22517
This commit is contained in:
Vladimir Kondratyev 2019-11-24 20:51:09 +00:00
parent 335fe0afb8
commit 71b8e362c5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=355068
1 changed files with 9 additions and 9 deletions
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18
sys/compat/linux/linux_event.c
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@ -557,13 +557,13 @@ linux_epoll_wait_common(struct thread *td, int epfd, struct epoll_event *events,
return (error);
if (epfp->f_type != DTYPE_KQUEUE) {
error = EINVAL;
goto leave1;
goto leave;
}
if (uset != NULL) {
error = kern_sigprocmask(td, SIG_SETMASK, uset,
&omask, 0);
if (error != 0)
goto leave1;
goto leave;
td->td_pflags |= TDP_OLDMASK;
/*
* Make sure that ast() is called on return to
@ -581,11 +581,12 @@ linux_epoll_wait_common(struct thread *td, int epfd, struct epoll_event *events,
coargs.count = 0;
coargs.error = 0;
if (timeout != -1) {
if (timeout < 0) {
error = EINVAL;
goto leave0;
}
/*
* Linux epoll_wait(2) man page states that timeout of -1 causes caller
* to block indefinitely. Real implementation does it if any negative
* timeout value is passed.
*/
if (timeout >= 0) {
/* Convert from milliseconds to timespec. */
ts.tv_sec = timeout / 1000;
ts.tv_nsec = (timeout % 1000) * 1000000;
@ -605,11 +606,10 @@ linux_epoll_wait_common(struct thread *td, int epfd, struct epoll_event *events,
if (error == 0)
td->td_retval[0] = coargs.count;
leave0:
if (uset != NULL)
error = kern_sigprocmask(td, SIG_SETMASK, &omask,
NULL, 0);
leave1:
leave:
fdrop(epfp, td);
return (error);
}