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| author | Robin Burchell <robin+git@viroteck.net> | 2019-05-18 18:55:56 +0200 |
|---|---|---|
| committer | Andreas Kling <awesomekling@gmail.com> | 2019-05-18 19:01:08 +0200 |
| commit | 99dd60611fd9abe5a4c9ef81682c0d7f1d91e5cb (patch) | |
| tree | 5a69f732003704c9dcea70c75f216d484818c2a4 | |
| parent | d2c3749cf3269d28726589b7c077d824dd97b1dd (diff) | |
| download | serenity-99dd60611fd9abe5a4c9ef81682c0d7f1d91e5cb.zip | |
Kernel: Fix select with a 0 timeout
select essentially has 3 modes (which is presumably why we're finding it
so hard to get this right in a reliable way :)).
1. NULL timeout -- no timeout on blocking
2. non-NULL timeout that is not zero'd -- timeout on blocking
3. non-NULL but zero timeout -- no blocking at all (immediate poll)
For cases 1 and 2, we want to block the thread. We have a timeout set
only for case 2, though.
Case 3 should not block the thread, and does not have a timeout set.
| -rw-r--r-- | Kernel/Process.cpp | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp index 274cacd851..3770954931 100644 --- a/Kernel/Process.cpp +++ b/Kernel/Process.cpp @@ -1757,7 +1757,7 @@ int Process::sys$select(const Syscall::SC_select_params* params) // FIXME: Implement exceptfds support. (void)exceptfds; - if (timeout) { + if (timeout && (timeout->tv_sec || timeout->tv_usec)) { struct timeval now; kgettimeofday(now); AK::timeval_add(&now, timeout, ¤t->m_select_timeout); @@ -1802,7 +1802,7 @@ int Process::sys$select(const Syscall::SC_select_params* params) dbgprintf("%s<%u> selecting on (read:%u, write:%u), timeout=%p\n", name().characters(), pid(), current->m_select_read_fds.size(), current->m_select_write_fds.size(), timeout); #endif - if (!timeout || (timeout->tv_sec || timeout->tv_usec)) + if (!timeout || current->m_select_has_timeout) current->block(Thread::State::BlockedSelect); int markedfds = 0; |