Bug 16816
| Summary: | vop_stdpoll() in /sys/kern/vfs_default.c does not handle POLLIN/POLLOUT | ||
|---|---|---|---|
| Product: | Base System | Reporter: | kenji.rikitake |
| Component: | kern | Assignee: | freebsd-bugs (Nobody) <bugs> |
| Status: | Closed FIXED | ||
| Severity: | Affects Only Me | ||
| Priority: | Normal | ||
| Version: | 3.4-RELEASE | ||
| Hardware: | Any | ||
| OS: | Any | ||
<<On 19 Feb 2000 03:49:55 -0000, kenji.rikitake@acm.org said: > --- /sys/kern/vfs_default.c Wed Jan 20 23:48:49 1999 > +++ vfs_default.c Sat Feb 19 12:44:43 2000 > @@ -285,7 +285,8 @@ > } */ *ap; > { > if ((ap->a_events & ~POLLSTANDARD) == 0) > - return (ap->a_events & (POLLRDNORM|POLLWRNORM)); > + return (ap->a_events & > + (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); > return (vn_pollrecord(ap->a_vp, ap->a_p, ap->a_events)); > } Looks fine to me. -GAWollman -- Garrett A. Wollman | O Siem / We are all family / O Siem / We're all the same wollman@lcs.mit.edu | O Siem / The fires of freedom Opinions not those of| Dance in the burning flame MIT, LCS, CRS, or NSA| - Susan Aglukark and Chad Irschick State Changed From-To: open->closed fixed. |
When monitoring stdin using poll() with event POLLIN, it works when stdin is redirected to a pipe, but it does not when stdin is redirected to a local system file (vfs). I think this behavior is weird because POLLIN seems to work for all the other devices/socket/pipe/file-systems buf vfs. Fix: This hasn't been tested yet, but I think changing the implementation of vop_stdpoll() in /sys/kern/vfs_default.c will solve this inconsistent behavior, by applying the following patch. I would also like FreeBSD Development Team to clarify the difference of semantics between POLLIN and POLLRDNORM, or POLLOUT and POLLWRNORM, and put the definition clearly on poll(2).--hIL0KlGdPCIXf4ZIcjH05MTyI0fvzvD5bU7a9XNLqUqJ4DGV Content-Type: text/plain; name="file.diff" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="file.diff" --- /sys/kern/vfs_default.c Wed Jan 20 23:48:49 1999 +++ vfs_default.c Sat Feb 19 12:44:43 2000 @@ -285,7 +285,8 @@ } */ *ap; { if ((ap->a_events & ~POLLSTANDARD) == 0) - return (ap->a_events & (POLLRDNORM|POLLWRNORM)); + return (ap->a_events & + (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)); return (vn_pollrecord(ap->a_vp, ap->a_p, ap->a_events)); } How-To-Repeat: cc -o poll-sample poll-sample.c echo "127.0.0.1" > foo cat ./foo | ./poll-sample retval = 1, revents=17 ./poll-sample < ~/.foo retval = 0, revents=0 (after waiting 10 seconds) when using POLLRDNORM for the value of x[0].events, the file redirection works as: retval = 1, revents=64 /* poll-sample.c */ #include <stdio.h> #include <poll.h> #include <sys/types.h> main() { struct pollfd x[1]; int i; x[0].fd = 0; x[0].events = POLLIN; i = poll(x, 1, 10000); printf("retval = %d, revents=%d\n", i, x[0].revents); } /* end of poll-sample.c */