Handle tmpfs with 5 fields in /proc/mounts parsing.

PiperOrigin-RevId: 370565903

test/syscalls/linux/mount.cc

@@ -45,6 +45,7 @@ namespace testing {
 
 namespace {
 
+using ::testing::AnyOf;
 using ::testing::Contains;
 using ::testing::Pair;
 
@@ -360,7 +361,8 @@ TEST(MountTest, MountInfo) {
     if (e.mount_point == dir.path()) {
       EXPECT_EQ(e.fstype, "tmpfs");
       auto mopts = ParseMountOptions(e.mount_opts);
-      EXPECT_THAT(mopts, Contains(Pair("mode", "0123")));
+      EXPECT_THAT(mopts, AnyOf(Contains(Pair("mode", "0123")),
+                               Contains(Pair("mode", "123"))));
     }
   }
 
@@ -371,7 +373,8 @@ TEST(MountTest, MountInfo) {
     if (e.mount_point == dir.path()) {
       EXPECT_EQ(e.fstype, "tmpfs");
       auto mopts = ParseMountOptions(e.super_opts);
-      EXPECT_THAT(mopts, Contains(Pair("mode", "0123")));
+      EXPECT_THAT(mopts, AnyOf(Contains(Pair("mode", "0123")),
+                               Contains(Pair("mode", "123"))));
     }
   }
 }

test/util/BUILD

@@ -149,6 +149,18 @@ cc_library(
     ],
 )
 
+cc_test(
+    name = "mount_util_test",
+    size = "small",
+    srcs = ["mount_util_test.cc"],
+    deps = [
+        ":mount_util",
+        ":test_main",
+        ":test_util",
+        gtest,
+    ],
+)
+
 cc_library(
     name = "save_util",
     testonly = 1,

test/util/mount_util.cc

@@ -26,9 +26,14 @@ namespace testing {
 PosixErrorOr<std::vector<ProcMountsEntry>> ProcSelfMountsEntries() {
   std::string content;
   RETURN_IF_ERRNO(GetContents("/proc/self/mounts", &content));
+  return ProcSelfMountsEntriesFrom(content);
+}
 
+PosixErrorOr<std::vector<ProcMountsEntry>> ProcSelfMountsEntriesFrom(
+    const std::string& content) {
   std::vector<ProcMountsEntry> entries;
-  std::vector<std::string> lines = absl::StrSplit(content, '\n');
+  std::vector<std::string> lines =
+      absl::StrSplit(content, absl::ByChar('\n'), absl::AllowEmpty());
   std::cerr << "<contents of /proc/self/mounts>" << std::endl;
   for (const std::string& line : lines) {
     std::cerr << line << std::endl;
@@ -47,11 +52,11 @@ PosixErrorOr<std::vector<ProcMountsEntry>> ProcSelfMountsEntries() {
 
     ProcMountsEntry entry;
     std::vector<std::string> fields =
-        absl::StrSplit(line, absl::ByChar(' '), absl::SkipEmpty());
+        absl::StrSplit(line, absl::ByChar(' '), absl::AllowEmpty());
     if (fields.size() != 6) {
-      return PosixError(EINVAL,
-                        absl::StrFormat("Not enough tokens, got %d, line: %s",
-                                        fields.size(), line));
+      return PosixError(
+          EINVAL, absl::StrFormat("Not enough tokens, got %d, content: <<%s>>",
+                                  fields.size(), content));
     }
 
     entry.spec = fields[0];
@@ -71,9 +76,14 @@ PosixErrorOr<std::vector<ProcMountsEntry>> ProcSelfMountsEntries() {
 PosixErrorOr<std::vector<ProcMountInfoEntry>> ProcSelfMountInfoEntries() {
   std::string content;
   RETURN_IF_ERRNO(GetContents("/proc/self/mountinfo", &content));
+  return ProcSelfMountInfoEntriesFrom(content);
+}
 
+PosixErrorOr<std::vector<ProcMountInfoEntry>> ProcSelfMountInfoEntriesFrom(
+    const std::string& content) {
   std::vector<ProcMountInfoEntry> entries;
-  std::vector<std::string> lines = absl::StrSplit(content, '\n');
+  std::vector<std::string> lines =
+      absl::StrSplit(content, absl::ByChar('\n'), absl::AllowEmpty());
   std::cerr << "<contents of /proc/self/mountinfo>" << std::endl;
   for (const std::string& line : lines) {
     std::cerr << line << std::endl;
@@ -92,12 +102,12 @@ PosixErrorOr<std::vector<ProcMountInfoEntry>> ProcSelfMountInfoEntries() {
 
     ProcMountInfoEntry entry;
     std::vector<std::string> fields =
-        absl::StrSplit(line, absl::ByChar(' '), absl::SkipEmpty());
+        absl::StrSplit(line, absl::ByChar(' '), absl::AllowEmpty());
     if (fields.size() < 10 || fields.size() > 11) {
       return PosixError(
-          EINVAL,
-          absl::StrFormat("Unexpected number of tokens, got %d, line: %s",
-                          fields.size(), line));
+          EINVAL, absl::StrFormat(
+                      "Unexpected number of tokens, got %d, content: <<%s>>",
+                      fields.size(), content));
     }
 
     ASSIGN_OR_RETURN_ERRNO(entry.id, Atoi<uint64_t>(fields[0]));
@@ -142,7 +152,7 @@ absl::flat_hash_map<std::string, std::string> ParseMountOptions(
     std::string mopts) {
   absl::flat_hash_map<std::string, std::string> entries;
   const std::vector<std::string> tokens =
-      absl::StrSplit(mopts, absl::ByChar(','), absl::SkipEmpty());
+      absl::StrSplit(mopts, absl::ByChar(','), absl::AllowEmpty());
   for (const auto& token : tokens) {
     std::vector<std::string> kv =
         absl::StrSplit(token, absl::MaxSplits('=', 1));

test/util/mount_util.h

@@ -58,6 +58,11 @@ struct ProcMountsEntry {
 // ProcSelfMountsEntries returns a parsed representation of /proc/self/mounts.
 PosixErrorOr<std::vector<ProcMountsEntry>> ProcSelfMountsEntries();
 
+// ProcSelfMountsEntries returns a parsed representation of mounts from the
+// provided content.
+PosixErrorOr<std::vector<ProcMountsEntry>> ProcSelfMountsEntriesFrom(
+    const std::string& content);
+
 struct ProcMountInfoEntry {
   uint64_t id;
   uint64_t parent_id;
@@ -76,6 +81,11 @@ struct ProcMountInfoEntry {
 // /proc/self/mountinfo.
 PosixErrorOr<std::vector<ProcMountInfoEntry>> ProcSelfMountInfoEntries();
 
+// ProcSelfMountInfoEntriesFrom returns a parsed representation of
+// mountinfo from the provided content.
+PosixErrorOr<std::vector<ProcMountInfoEntry>> ProcSelfMountInfoEntriesFrom(
+    const std::string&);
+
 // Interprets the input string mopts as a comma separated list of mount
 // options. A mount option can either be just a value, or a key=value pair. For
 // example, the string "rw,relatime,fd=7" will be parsed into a map like { "rw":

test/util/mount_util_test.cc

@@ -0,0 +1,47 @@
+// Copyright 2018 The gVisor Authors.
+//
+// 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.
+
+#include "test/util/mount_util.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+TEST(ParseMounts, Mounts) {
+  auto entries = ASSERT_NO_ERRNO_AND_VALUE(ProcSelfMountsEntriesFrom(
+      R"proc(sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
+proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
+ /mnt tmpfs rw,noexec 0 0
+)proc"));
+  EXPECT_EQ(entries.size(), 3);
+}
+
+TEST(ParseMounts, MountInfo) {
+  auto entries = ASSERT_NO_ERRNO_AND_VALUE(ProcSelfMountInfoEntriesFrom(
+      R"proc(22 28 0:20 / /sys rw,relatime shared:7 - sysfs sysfs rw
+23 28 0:21 / /proc rw,relatime shared:14 - proc proc rw
+2007 8844 0:278 / /mnt rw,noexec - tmpfs  rw,mode=123,uid=268601820,gid=5000
+)proc"));
+  EXPECT_EQ(entries.size(), 3);
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor