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gvisor/test/syscalls/linux/proc_pid_smaps.cc

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// Copyright 2019 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.
#include <stddef.h>
#include <stdint.h>
#include <algorithm>
#include <string>
#include <utility>
#include <vector>
#include "absl/container/flat_hash_set.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_format.h"
#include "absl/strings/str_split.h"
#include "absl/strings/string_view.h"
#include "absl/types/optional.h"
#include "test/util/file_descriptor.h"
#include "test/util/fs_util.h"
#include "test/util/memory_util.h"
#include "test/util/posix_error.h"
#include "test/util/proc_util.h"
#include "test/util/temp_path.h"
#include "test/util/test_util.h"
using ::testing::Contains;
using ::testing::ElementsAreArray;
using ::testing::IsSupersetOf;
using ::testing::Not;
using ::testing::Optional;
namespace gvisor {
namespace testing {
namespace {
struct ProcPidSmapsEntry {
ProcMapsEntry maps_entry;
// These fields should always exist, as they were included in e070ad49f311
// "[PATCH] add /proc/pid/smaps".
size_t size_kb;
size_t rss_kb;
size_t shared_clean_kb;
size_t shared_dirty_kb;
size_t private_clean_kb;
size_t private_dirty_kb;
// These fields were added later and may not be present.
absl::optional<size_t> pss_kb;
absl::optional<size_t> referenced_kb;
absl::optional<size_t> anonymous_kb;
absl::optional<size_t> anon_huge_pages_kb;
absl::optional<size_t> shared_hugetlb_kb;
absl::optional<size_t> private_hugetlb_kb;
absl::optional<size_t> swap_kb;
absl::optional<size_t> swap_pss_kb;
absl::optional<size_t> kernel_page_size_kb;
absl::optional<size_t> mmu_page_size_kb;
absl::optional<size_t> locked_kb;
// Caution: "Note that there is no guarantee that every flag and associated
// mnemonic will be present in all further kernel releases. Things get
// changed, the flags may be vanished or the reverse -- new added." - Linux
// Documentation/filesystems/proc.txt, on VmFlags. Avoid checking for any
// flags that are not extremely well-established.
absl::optional<std::vector<std::string>> vm_flags;
};
// Given the value part of a /proc/[pid]/smaps field containing a value in kB
// (for example, " 4 kB", returns the value in kB (in this example, 4).
PosixErrorOr<size_t> SmapsValueKb(absl::string_view value) {
// TODO: let us use RE2 or <regex>
std::pair<absl::string_view, absl::string_view> parts =
absl::StrSplit(value, ' ', absl::SkipEmpty());
if (parts.second != "kB") {
return PosixError(EINVAL,
absl::StrCat("invalid smaps field value: ", value));
}
ASSIGN_OR_RETURN_ERRNO(auto val_kb, Atoi<size_t>(parts.first));
return val_kb;
}
PosixErrorOr<std::vector<ProcPidSmapsEntry>> ParseProcPidSmaps(
absl::string_view contents) {
std::vector<ProcPidSmapsEntry> entries;
absl::optional<ProcPidSmapsEntry> entry;
bool have_size_kb = false;
bool have_rss_kb = false;
bool have_shared_clean_kb = false;
bool have_shared_dirty_kb = false;
bool have_private_clean_kb = false;
bool have_private_dirty_kb = false;
auto const finish_entry = [&] {
if (entry) {
if (!have_size_kb) {
return PosixError(EINVAL, "smaps entry is missing Size");
}
if (!have_rss_kb) {
return PosixError(EINVAL, "smaps entry is missing Rss");
}
if (!have_shared_clean_kb) {
return PosixError(EINVAL, "smaps entry is missing Shared_Clean");
}
if (!have_shared_dirty_kb) {
return PosixError(EINVAL, "smaps entry is missing Shared_Dirty");
}
if (!have_private_clean_kb) {
return PosixError(EINVAL, "smaps entry is missing Private_Clean");
}
if (!have_private_dirty_kb) {
return PosixError(EINVAL, "smaps entry is missing Private_Dirty");
}
// std::move(entry.value()) instead of std::move(entry).value(), because
// otherwise tools may report a "use-after-move" warning, which is
// spurious because entry.emplace() below resets entry to a new
// ProcPidSmapsEntry.
entries.emplace_back(std::move(entry.value()));
}
entry.emplace();
have_size_kb = false;
have_rss_kb = false;
have_shared_clean_kb = false;
have_shared_dirty_kb = false;
have_private_clean_kb = false;
have_private_dirty_kb = false;
return NoError();
};
// Holds key/value pairs from smaps field lines. Declared here so it can be
// captured by reference by the following lambdas.
std::vector<absl::string_view> key_value;
auto const on_required_field_kb = [&](size_t* field, bool* have_field) {
if (*have_field) {
return PosixError(
EINVAL,
absl::StrFormat("smaps entry has duplicate %s line", key_value[0]));
}
ASSIGN_OR_RETURN_ERRNO(*field, SmapsValueKb(key_value[1]));
*have_field = true;
return NoError();
};
auto const on_optional_field_kb = [&](absl::optional<size_t>* field) {
if (*field) {
return PosixError(
EINVAL,
absl::StrFormat("smaps entry has duplicate %s line", key_value[0]));
}
ASSIGN_OR_RETURN_ERRNO(*field, SmapsValueKb(key_value[1]));
return NoError();
};
absl::flat_hash_set<std::string> unknown_fields;
auto const on_unknown_field = [&] {
absl::string_view key = key_value[0];
// Don't mention unknown fields more than once.
if (unknown_fields.count(key)) {
return;
}
unknown_fields.insert(std::string(key));
LOG(INFO) << "skipping unknown smaps field " << key;
};
auto lines = absl::StrSplit(contents, '\n', absl::SkipEmpty());
for (absl::string_view l : lines) {
// Is this line a valid /proc/[pid]/maps entry?
auto maybe_maps_entry = ParseProcMapsLine(l);
if (maybe_maps_entry.ok()) {
// This marks the beginning of a new /proc/[pid]/smaps entry.
RETURN_IF_ERRNO(finish_entry());
entry->maps_entry = std::move(maybe_maps_entry).ValueOrDie();
continue;
}
// Otherwise it's a field in an existing /proc/[pid]/smaps entry of the form
// "key:value" (where value in practice will be preceded by a variable
// amount of whitespace).
if (!entry) {
LOG(WARNING) << "smaps line not considered a maps line: "
<< maybe_maps_entry.error_message();
return PosixError(
EINVAL,
absl::StrCat("smaps field line without preceding maps line: ", l));
}
key_value = absl::StrSplit(l, absl::MaxSplits(':', 1));
if (key_value.size() != 2) {
return PosixError(EINVAL, absl::StrCat("invalid smaps field line: ", l));
}
absl::string_view const key = key_value[0];
if (key == "Size") {
RETURN_IF_ERRNO(on_required_field_kb(&entry->size_kb, &have_size_kb));
} else if (key == "Rss") {
RETURN_IF_ERRNO(on_required_field_kb(&entry->rss_kb, &have_rss_kb));
} else if (key == "Shared_Clean") {
RETURN_IF_ERRNO(
on_required_field_kb(&entry->shared_clean_kb, &have_shared_clean_kb));
} else if (key == "Shared_Dirty") {
RETURN_IF_ERRNO(
on_required_field_kb(&entry->shared_dirty_kb, &have_shared_dirty_kb));
} else if (key == "Private_Clean") {
RETURN_IF_ERRNO(on_required_field_kb(&entry->private_clean_kb,
&have_private_clean_kb));
} else if (key == "Private_Dirty") {
RETURN_IF_ERRNO(on_required_field_kb(&entry->private_dirty_kb,
&have_private_dirty_kb));
} else if (key == "Pss") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->pss_kb));
} else if (key == "Referenced") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->referenced_kb));
} else if (key == "Anonymous") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->anonymous_kb));
} else if (key == "AnonHugePages") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->anon_huge_pages_kb));
} else if (key == "Shared_Hugetlb") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->shared_hugetlb_kb));
} else if (key == "Private_Hugetlb") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->private_hugetlb_kb));
} else if (key == "Swap") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->swap_kb));
} else if (key == "SwapPss") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->swap_pss_kb));
} else if (key == "KernelPageSize") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->kernel_page_size_kb));
} else if (key == "MMUPageSize") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->mmu_page_size_kb));
} else if (key == "Locked") {
RETURN_IF_ERRNO(on_optional_field_kb(&entry->locked_kb));
} else if (key == "VmFlags") {
if (entry->vm_flags) {
return PosixError(EINVAL, "duplicate VmFlags line");
}
entry->vm_flags = absl::StrSplit(key_value[1], ' ', absl::SkipEmpty());
} else {
on_unknown_field();
}
}
RETURN_IF_ERRNO(finish_entry());
return entries;
};
TEST(ParseProcPidSmapsTest, Correctness) {
auto entries = ASSERT_NO_ERRNO_AND_VALUE(
ParseProcPidSmaps("0-10000 rw-s 00000000 00:00 0 "
" /dev/zero (deleted)\n"
"Size: 0 kB\n"
"Rss: 1 kB\n"
"Pss: 2 kB\n"
"Shared_Clean: 3 kB\n"
"Shared_Dirty: 4 kB\n"
"Private_Clean: 5 kB\n"
"Private_Dirty: 6 kB\n"
"Referenced: 7 kB\n"
"Anonymous: 8 kB\n"
"AnonHugePages: 9 kB\n"
"Shared_Hugetlb: 10 kB\n"
"Private_Hugetlb: 11 kB\n"
"Swap: 12 kB\n"
"SwapPss: 13 kB\n"
"KernelPageSize: 14 kB\n"
"MMUPageSize: 15 kB\n"
"Locked: 16 kB\n"
"FutureUnknownKey: 17 kB\n"
"VmFlags: rd wr sh mr mw me ms lo ?? sd \n"));
ASSERT_EQ(entries.size(), 1);
auto& entry = entries[0];
EXPECT_EQ(entry.maps_entry.filename, "/dev/zero (deleted)");
EXPECT_EQ(entry.size_kb, 0);
EXPECT_EQ(entry.rss_kb, 1);
EXPECT_THAT(entry.pss_kb, Optional(2));
EXPECT_EQ(entry.shared_clean_kb, 3);
EXPECT_EQ(entry.shared_dirty_kb, 4);
EXPECT_EQ(entry.private_clean_kb, 5);
EXPECT_EQ(entry.private_dirty_kb, 6);
EXPECT_THAT(entry.referenced_kb, Optional(7));
EXPECT_THAT(entry.anonymous_kb, Optional(8));
EXPECT_THAT(entry.anon_huge_pages_kb, Optional(9));
EXPECT_THAT(entry.shared_hugetlb_kb, Optional(10));
EXPECT_THAT(entry.private_hugetlb_kb, Optional(11));
EXPECT_THAT(entry.swap_kb, Optional(12));
EXPECT_THAT(entry.swap_pss_kb, Optional(13));
EXPECT_THAT(entry.kernel_page_size_kb, Optional(14));
EXPECT_THAT(entry.mmu_page_size_kb, Optional(15));
EXPECT_THAT(entry.locked_kb, Optional(16));
EXPECT_THAT(entry.vm_flags,
Optional(ElementsAreArray({"rd", "wr", "sh", "mr", "mw", "me",
"ms", "lo", "??", "sd"})));
}
// Returns the unique entry in entries containing the given address.
PosixErrorOr<ProcPidSmapsEntry> FindUniqueSmapsEntry(
std::vector<ProcPidSmapsEntry> const& entries, uintptr_t addr) {
auto const pred = [&](ProcPidSmapsEntry const& entry) {
return entry.maps_entry.start <= addr && addr < entry.maps_entry.end;
};
auto const it = std::find_if(entries.begin(), entries.end(), pred);
if (it == entries.end()) {
return PosixError(EINVAL,
absl::StrFormat("no entry contains address %#x", addr));
}
auto const it2 = std::find_if(it + 1, entries.end(), pred);
if (it2 != entries.end()) {
return PosixError(
EINVAL,
absl::StrFormat("overlapping entries [%#x-%#x) and [%#x-%#x) both "
"contain address %#x",
it->maps_entry.start, it->maps_entry.end,
it2->maps_entry.start, it2->maps_entry.end, addr));
}
return *it;
}
PosixErrorOr<std::vector<ProcPidSmapsEntry>> ReadProcSelfSmaps() {
ASSIGN_OR_RETURN_ERRNO(std::string contents, GetContents("/proc/self/smaps"));
return ParseProcPidSmaps(contents);
}
TEST(ProcPidSmapsTest, SharedAnon) {
// Map with MAP_POPULATE so we get some RSS.
Mapping const m = ASSERT_NO_ERRNO_AND_VALUE(MmapAnon(
2 * kPageSize, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE));
auto const entries = ASSERT_NO_ERRNO_AND_VALUE(ReadProcSelfSmaps());
auto const entry =
ASSERT_NO_ERRNO_AND_VALUE(FindUniqueSmapsEntry(entries, m.addr()));
EXPECT_EQ(entry.size_kb, m.len() / 1024);
// It's possible that populated pages have been swapped out, so RSS might be
// less than size.
EXPECT_LE(entry.rss_kb, entry.size_kb);
if (entry.pss_kb) {
// PSS should be exactly equal to RSS since no other address spaces should
// be sharing our new mapping.
EXPECT_EQ(entry.pss_kb.value(), entry.rss_kb);
}
// "Shared" and "private" in smaps refers to whether or not *physical pages*
// are shared; thus all pages in our MAP_SHARED mapping should nevertheless
// be private.
EXPECT_EQ(entry.shared_clean_kb, 0);
EXPECT_EQ(entry.shared_dirty_kb, 0);
EXPECT_EQ(entry.private_clean_kb + entry.private_dirty_kb, entry.rss_kb)
<< "Private_Clean = " << entry.private_clean_kb
<< " kB, Private_Dirty = " << entry.private_dirty_kb << " kB";
// Shared anonymous mappings are implemented as a shmem file, so their pages
// are not PageAnon.
if (entry.anonymous_kb) {
EXPECT_EQ(entry.anonymous_kb.value(), 0);
}
if (entry.vm_flags) {
EXPECT_THAT(entry.vm_flags.value(),
IsSupersetOf({"rd", "wr", "sh", "mr", "mw", "me", "ms"}));
EXPECT_THAT(entry.vm_flags.value(), Not(Contains("ex")));
}
}
TEST(ProcPidSmapsTest, PrivateAnon) {
// Map with MAP_POPULATE so we get some RSS.
Mapping const m = ASSERT_NO_ERRNO_AND_VALUE(
MmapAnon(2 * kPageSize, PROT_WRITE, MAP_PRIVATE | MAP_POPULATE));
auto const entries = ASSERT_NO_ERRNO_AND_VALUE(ReadProcSelfSmaps());
auto const entry =
ASSERT_NO_ERRNO_AND_VALUE(FindUniqueSmapsEntry(entries, m.addr()));
// It's possible that our mapping was merged with another vma, so the smaps
// entry might be bigger than our original mapping.
EXPECT_GE(entry.size_kb, m.len() / 1024);
EXPECT_LE(entry.rss_kb, entry.size_kb);
if (entry.pss_kb) {
EXPECT_LE(entry.pss_kb.value(), entry.rss_kb);
}
if (entry.anonymous_kb) {
EXPECT_EQ(entry.anonymous_kb.value(), entry.rss_kb);
}
if (entry.vm_flags) {
EXPECT_THAT(entry.vm_flags.value(), IsSupersetOf({"wr", "mr", "mw", "me"}));
// We passed PROT_WRITE to mmap. On at least x86, the mapping is in
// practice readable because there is no way to configure the MMU to make
// pages writable but not readable. However, VmFlags should reflect the
// flags set on the VMA, so "rd" (VM_READ) should not appear in VmFlags.
EXPECT_THAT(entry.vm_flags.value(), Not(Contains("rd")));
EXPECT_THAT(entry.vm_flags.value(), Not(Contains("ex")));
EXPECT_THAT(entry.vm_flags.value(), Not(Contains("sh")));
EXPECT_THAT(entry.vm_flags.value(), Not(Contains("ms")));
}
}
TEST(ProcPidSmapsTest, SharedReadOnlyFile) {
size_t const kFileSize = kPageSize;
auto const temp_file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
ASSERT_THAT(truncate(temp_file.path().c_str(), kFileSize), SyscallSucceeds());
auto const fd = ASSERT_NO_ERRNO_AND_VALUE(Open(temp_file.path(), O_RDONLY));
auto const m = ASSERT_NO_ERRNO_AND_VALUE(Mmap(
nullptr, kFileSize, PROT_READ, MAP_SHARED | MAP_POPULATE, fd.get(), 0));
auto const entries = ASSERT_NO_ERRNO_AND_VALUE(ReadProcSelfSmaps());
auto const entry =
ASSERT_NO_ERRNO_AND_VALUE(FindUniqueSmapsEntry(entries, m.addr()));
// Most of the same logic as the SharedAnon case applies.
EXPECT_EQ(entry.size_kb, kFileSize / 1024);
EXPECT_LE(entry.rss_kb, entry.size_kb);
if (entry.pss_kb) {
EXPECT_EQ(entry.pss_kb.value(), entry.rss_kb);
}
EXPECT_EQ(entry.shared_clean_kb, 0);
EXPECT_EQ(entry.shared_dirty_kb, 0);
EXPECT_EQ(entry.private_clean_kb + entry.private_dirty_kb, entry.rss_kb)
<< "Private_Clean = " << entry.private_clean_kb
<< " kB, Private_Dirty = " << entry.private_dirty_kb << " kB";
if (entry.anonymous_kb) {
EXPECT_EQ(entry.anonymous_kb.value(), 0);
}
if (entry.vm_flags) {
EXPECT_THAT(entry.vm_flags.value(), IsSupersetOf({"rd", "mr", "me", "ms"}));
EXPECT_THAT(entry.vm_flags.value(), Not(Contains("wr")));
EXPECT_THAT(entry.vm_flags.value(), Not(Contains("ex")));
// Because the mapped file was opened O_RDONLY, the VMA is !VM_MAYWRITE and
// also !VM_SHARED.
EXPECT_THAT(entry.vm_flags.value(), Not(Contains("sh")));
EXPECT_THAT(entry.vm_flags.value(), Not(Contains("mw")));
}
}
// Tests that gVisor's /proc/[pid]/smaps provides all of the fields we expect it
// to, which as of this writing is all fields provided by Linux 4.4.
TEST(ProcPidSmapsTest, GvisorFields) {
SKIP_IF(!IsRunningOnGvisor());
auto const entries = ASSERT_NO_ERRNO_AND_VALUE(ReadProcSelfSmaps());
for (auto const& entry : entries) {
EXPECT_TRUE(entry.pss_kb);
EXPECT_TRUE(entry.referenced_kb);
EXPECT_TRUE(entry.anonymous_kb);
EXPECT_TRUE(entry.anon_huge_pages_kb);
EXPECT_TRUE(entry.shared_hugetlb_kb);
EXPECT_TRUE(entry.private_hugetlb_kb);
EXPECT_TRUE(entry.swap_kb);
EXPECT_TRUE(entry.swap_pss_kb);
EXPECT_THAT(entry.kernel_page_size_kb, Optional(kPageSize / 1024));
EXPECT_THAT(entry.mmu_page_size_kb, Optional(kPageSize / 1024));
EXPECT_TRUE(entry.locked_kb);
EXPECT_TRUE(entry.vm_flags);
}
}
} // namespace
} // namespace testing
} // namespace gvisor
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