Format signals, signal masks in strace

Sample:

I1205 16:51:49.869701    2492 x:0] [   1] ioctl_test E rt_sigaction(SIGIO, 0x7e0e5b5e8500, 0x7e0e5b5e85a0)
I1205 16:51:49.869766    2492 x:0] [   1] ioctl_test X rt_sigaction(SIGIO, 0x7e0e5b5e8500, 0x7e0e5b5e85a0) = 0x0 (44.336?s)
I1205 16:51:49.869831    2492 x:0] [   1] ioctl_test E rt_sigprocmask(SIG_UNBLOCK, 0x7e0e5b5e8878 [SIGIO], 0x7e0e5b5e87c0, 0x8)
I1205 16:51:49.869866    2492 x:0] [   1] ioctl_test X rt_sigprocmask(SIG_UNBLOCK, 0x7e0e5b5e8878 [SIGIO], 0x7e0e5b5e87c0 [SIGIO 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64], 0x8) = 0x0 (2.575?s)

PiperOrigin-RevId: 224422404
Change-Id: I3ed3f2ec6b1a639baa9cacd37ce7ee325c3703e4

1 files changed, 86 insertions, 0 deletions

diff --git a/pkg/sentry/strace/signal.go b/pkg/sentry/strace/signal.go
new file mode 100644
index 000000000..00ed02a3c
--- /dev/null
+++ b/pkg/sentry/strace/signal.go
@@ -0,0 +1,86 @@
+// Copyright 2018 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package strace
+
+import (
+	"fmt"
+	"strings"
+
+	"gvisor.googlesource.com/gvisor/pkg/abi"
+	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/usermem"
+)
+
+// signalNames contains the names of all named signals.
+var signalNames = abi.ValueSet{
+	uint64(linux.SIGABRT):   "SIGABRT",
+	uint64(linux.SIGALRM):   "SIGALRM",
+	uint64(linux.SIGBUS):    "SIGBUS",
+	uint64(linux.SIGCHLD):   "SIGCHLD",
+	uint64(linux.SIGCONT):   "SIGCONT",
+	uint64(linux.SIGFPE):    "SIGFPE",
+	uint64(linux.SIGHUP):    "SIGHUP",
+	uint64(linux.SIGILL):    "SIGILL",
+	uint64(linux.SIGINT):    "SIGINT",
+	uint64(linux.SIGIO):     "SIGIO",
+	uint64(linux.SIGKILL):   "SIGKILL",
+	uint64(linux.SIGPIPE):   "SIGPIPE",
+	uint64(linux.SIGPROF):   "SIGPROF",
+	uint64(linux.SIGPWR):    "SIGPWR",
+	uint64(linux.SIGQUIT):   "SIGQUIT",
+	uint64(linux.SIGSEGV):   "SIGSEGV",
+	uint64(linux.SIGSTKFLT): "SIGSTKFLT",
+	uint64(linux.SIGSTOP):   "SIGSTOP",
+	uint64(linux.SIGSYS):    "SIGSYS",
+	uint64(linux.SIGTERM):   "SIGTERM",
+	uint64(linux.SIGTRAP):   "SIGTRAP",
+	uint64(linux.SIGTSTP):   "SIGTSTP",
+	uint64(linux.SIGTTIN):   "SIGTTIN",
+	uint64(linux.SIGTTOU):   "SIGTTOU",
+	uint64(linux.SIGURG):    "SIGURG",
+	uint64(linux.SIGUSR1):   "SIGUSR1",
+	uint64(linux.SIGUSR2):   "SIGUSR2",
+	uint64(linux.SIGVTALRM): "SIGVTALRM",
+	uint64(linux.SIGWINCH):  "SIGWINCH",
+	uint64(linux.SIGXCPU):   "SIGXCPU",
+	uint64(linux.SIGXFSZ):   "SIGXFSZ",
+}
+
+var signalMaskActions = abi.ValueSet{
+	linux.SIG_BLOCK:   "SIG_BLOCK",
+	linux.SIG_UNBLOCK: "SIG_UNBLOCK",
+	linux.SIG_SETMASK: "SIG_SETMASK",
+}
+
+func sigSet(t *kernel.Task, addr usermem.Addr) string {
+	if addr == 0 {
+		return "null"
+	}
+
+	var b [linux.SignalSetSize]byte
+	if _, err := t.CopyInBytes(addr, b[:]); err != nil {
+		return fmt.Sprintf("%#x (error copying sigset: %v)", addr, err)
+	}
+
+	set := linux.SignalSet(usermem.ByteOrder.Uint64(b[:]))
+
+	var signals []string
+	linux.ForEachSignal(set, func(sig linux.Signal) {
+		signals = append(signals, signalNames.ParseDecimal(uint64(sig)))
+	})
+
+	return fmt.Sprintf("%#x [%v]", addr, strings.Join(signals, " "))
+}