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PiperOrigin-RevId: 194583126
Change-Id: Ica1d8821a90f74e7e745962d71801c598c652463

1 files changed, 100 insertions, 0 deletions

diff --git a/pkg/sentry/kernel/syslog.go b/pkg/sentry/kernel/syslog.go
new file mode 100644
index 000000000..31541749e
--- /dev/null
+++ b/pkg/sentry/kernel/syslog.go
@@ -0,0 +1,100 @@
+// Copyright 2018 Google Inc.
+//
+// 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 kernel
+
+import (
+	"fmt"
+	"math/rand"
+	"sync"
+)
+
+// syslog represents a sentry-global kernel log.
+//
+// Currently, it contains only fun messages for a dmesg easter egg.
+type syslog struct {
+	// mu protects the below.
+	mu sync.Mutex `state:"nosave"`
+
+	// msg is the syslog message buffer. It is lazily initialized.
+	msg []byte
+}
+
+// Log returns a copy of the syslog.
+func (s *syslog) Log() []byte {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if s.msg != nil {
+		// Already initialized, just return a copy.
+		o := make([]byte, len(s.msg))
+		copy(o, s.msg)
+		return o
+	}
+
+	// Not initialized, create message.
+	allMessages := []string{
+		"Synthesizing system calls...",
+		"Mounting deweydecimalfs...",
+		"Moving files to filing cabinet...",
+		"Digging up root...",
+		"Constructing home...",
+		"Segmenting fault lines...",
+		"Creating bureaucratic processes...",
+		"Searching for needles in stacks...",
+		"Preparing for the zombie uprising...",
+		"Feeding the init monster...",
+		"Creating cloned children...",
+		"Daemonizing children...",
+		"Waiting for children...",
+		"Gathering forks...",
+		"Committing treasure map to memory...",
+		"Reading process obituaries...",
+		"Searching for socket adapter...",
+		"Creating process schedule...",
+		"Generating random numbers by fair dice roll...",
+		"Rewriting operating system in Javascript...",
+		"Consulting tar man page...",
+		"Forking spaghetti code...",
+		"Checking naughty and nice process list...",
+		"Checking naughty and nice process list...", // Check it up to twice.
+		"Granting licence to kill(2)...",            // British spelling for British movie.
+		"Letting the watchdogs out...",
+	}
+
+	selectMessage := func() string {
+		i := rand.Intn(len(allMessages))
+		m := allMessages[i]
+
+		// Delete the selected message.
+		allMessages[i] = allMessages[len(allMessages)-1]
+		allMessages = allMessages[:len(allMessages)-1]
+
+		return m
+	}
+
+	time := 0.0
+	for i := 0; i < 10; i++ {
+		time += rand.Float64() / 2
+		s.msg = append(s.msg, []byte(fmt.Sprintf("<6>[%11.6f] %s\n", time, selectMessage()))...)
+	}
+
+	time += rand.Float64() / 2
+	s.msg = append(s.msg, []byte(fmt.Sprintf("<6>[%11.6f] Ready!\n", time))...)
+
+	// Return a copy.
+	o := make([]byte, len(s.msg))
+	copy(o, s.msg)
+	return o
+}