From eefa00f4aecc7c72a1866357fbd1bbb58aa6fc5e Mon Sep 17 00:00:00 2001
From: Jing Chen <chjing@google.com>
Date: Thu, 29 Apr 2021 15:19:22 -0700
Subject: Implement epoll_pwait2.

PiperOrigin-RevId: 371216407
---
 pkg/sentry/syscalls/linux/vfs2/epoll.go | 52 ++++++++++++++++++++++++++-------
 pkg/sentry/syscalls/linux/vfs2/vfs2.go  |  2 ++
 2 files changed, 44 insertions(+), 10 deletions(-)

(limited to 'pkg/sentry/syscalls/linux/vfs2')

diff --git a/pkg/sentry/syscalls/linux/vfs2/epoll.go b/pkg/sentry/syscalls/linux/vfs2/epoll.go
index b980aa43e..047d955b6 100644
--- a/pkg/sentry/syscalls/linux/vfs2/epoll.go
+++ b/pkg/sentry/syscalls/linux/vfs2/epoll.go
@@ -19,6 +19,7 @@ import (
 	"time"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/hostarch"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
@@ -118,13 +119,7 @@ func EpollCtl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
 	}
 }
 
-// EpollWait implements Linux syscall epoll_wait(2).
-func EpollWait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
-	epfd := args[0].Int()
-	eventsAddr := args[1].Pointer()
-	maxEvents := int(args[2].Int())
-	timeout := int(args[3].Int())
-
+func waitEpoll(t *kernel.Task, epfd int32, eventsAddr hostarch.Addr, maxEvents int, timeoutInNanos int64) (uintptr, *kernel.SyscallControl, error) {
 	var _EP_MAX_EVENTS = math.MaxInt32 / sizeofEpollEvent // Linux: fs/eventpoll.c:EP_MAX_EVENTS
 	if maxEvents <= 0 || maxEvents > _EP_MAX_EVENTS {
 		return 0, nil, syserror.EINVAL
@@ -158,7 +153,7 @@ func EpollWait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys
 			}
 			return 0, nil, err
 		}
-		if timeout == 0 {
+		if timeoutInNanos == 0 {
 			return 0, nil, nil
 		}
 		// In the first iteration of this loop, register with the epoll
@@ -173,8 +168,8 @@ func EpollWait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys
 			defer epfile.EventUnregister(&w)
 		} else {
 			// Set up the timer if a timeout was specified.
-			if timeout > 0 && !haveDeadline {
-				timeoutDur := time.Duration(timeout) * time.Millisecond
+			if timeoutInNanos > 0 && !haveDeadline {
+				timeoutDur := time.Duration(timeoutInNanos) * time.Nanosecond
 				deadline = t.Kernel().MonotonicClock().Now().Add(timeoutDur)
 				haveDeadline = true
 			}
@@ -186,6 +181,17 @@ func EpollWait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys
 			}
 		}
 	}
+
+}
+
+// EpollWait implements Linux syscall epoll_wait(2).
+func EpollWait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	epfd := args[0].Int()
+	eventsAddr := args[1].Pointer()
+	maxEvents := int(args[2].Int())
+	timeoutInNanos := int64(args[3].Int()) * 1000000
+
+	return waitEpoll(t, epfd, eventsAddr, maxEvents, timeoutInNanos)
 }
 
 // EpollPwait implements Linux syscall epoll_pwait(2).
@@ -199,3 +205,29 @@ func EpollPwait(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sy
 
 	return EpollWait(t, args)
 }
+
+// EpollPwait2 implements Linux syscall epoll_pwait(2).
+func EpollPwait2(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+	epfd := args[0].Int()
+	eventsAddr := args[1].Pointer()
+	maxEvents := int(args[2].Int())
+	timeoutPtr := args[3].Pointer()
+	maskAddr := args[4].Pointer()
+	maskSize := uint(args[5].Uint())
+	haveTimeout := timeoutPtr != 0
+
+	var timeoutInNanos int64 = -1
+	if haveTimeout {
+		var timeout linux.Timespec
+		if _, err := timeout.CopyIn(t, timeoutPtr); err != nil {
+			return 0, nil, err
+		}
+		timeoutInNanos = timeout.ToNsec()
+	}
+
+	if err := setTempSignalSet(t, maskAddr, maskSize); err != nil {
+		return 0, nil, err
+	}
+
+	return waitEpoll(t, epfd, eventsAddr, maxEvents, timeoutInNanos)
+}
diff --git a/pkg/sentry/syscalls/linux/vfs2/vfs2.go b/pkg/sentry/syscalls/linux/vfs2/vfs2.go
index c50fd97eb..0fc81e694 100644
--- a/pkg/sentry/syscalls/linux/vfs2/vfs2.go
+++ b/pkg/sentry/syscalls/linux/vfs2/vfs2.go
@@ -159,6 +159,7 @@ func Override() {
 	s.Table[327] = syscalls.Supported("preadv2", Preadv2)
 	s.Table[328] = syscalls.Supported("pwritev2", Pwritev2)
 	s.Table[332] = syscalls.Supported("statx", Statx)
+	s.Table[441] = syscalls.Supported("epoll_pwait2", EpollPwait2)
 	s.Init()
 
 	// Override ARM64.
@@ -269,6 +270,7 @@ func Override() {
 	s.Table[286] = syscalls.Supported("preadv2", Preadv2)
 	s.Table[287] = syscalls.Supported("pwritev2", Pwritev2)
 	s.Table[291] = syscalls.Supported("statx", Statx)
+	s.Table[441] = syscalls.Supported("epoll_pwait2", EpollPwait2)
 
 	s.Init()
 }
-- 
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