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+// 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.
+
+#include <elf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <sched.h>
+#include <signal.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <sys/stat.h>
+#include <sys/utsname.h>
+#include <syscall.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <atomic>
+#include <functional>
+#include <map>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/strings/ascii.h"
+#include "absl/strings/match.h"
+#include "absl/strings/numbers.h"
+#include "absl/strings/str_cat.h"
+#include "absl/strings/str_split.h"
+#include "absl/strings/string_view.h"
+#include "absl/synchronization/mutex.h"
+#include "absl/time/clock.h"
+#include "absl/time/time.h"
+#include "test/util/capability_util.h"
+#include "test/util/cleanup.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/temp_path.h"
+#include "test/util/test_util.h"
+#include "test/util/thread_util.h"
+#include "test/util/timer_util.h"
+
+// NOTE: No, this isn't really a syscall but this is a really simple
+// way to get it tested on both gVisor, PTrace and Linux.
+
+using ::testing::AllOf;
+using ::testing::ContainerEq;
+using ::testing::Contains;
+using ::testing::ContainsRegex;
+using ::testing::Gt;
+using ::testing::HasSubstr;
+using ::testing::IsSupersetOf;
+using ::testing::Pair;
+using ::testing::UnorderedElementsAre;
+using ::testing::UnorderedElementsAreArray;
+
+// Exported by glibc.
+extern char** environ;
+
+namespace gvisor {
+namespace testing {
+namespace {
+
+// O_LARGEFILE as defined by Linux. glibc tries to be clever by setting it to 0
+// because "it isn't needed", even though Linux can return it via F_GETFL.
+constexpr int kOLargeFile = 00100000;
+
+// Takes the subprocess command line and pid.
+// If it returns !OK, WithSubprocess returns immediately.
+using SubprocessCallback = std::function<PosixError(int)>;
+
+std::vector<std::string> saved_argv; // NOLINT
+
+// Helper function to dump /proc/{pid}/status and check the
+// state data. State should = "Z" for zombied or "RSD" for
+// running, interruptible sleeping (S), or uninterruptible sleep
+// (D).
+void CompareProcessState(absl::string_view state, int pid) {
+ auto status_file = ASSERT_NO_ERRNO_AND_VALUE(
+ GetContents(absl::StrCat("/proc/", pid, "/status")));
+ EXPECT_THAT(status_file, ContainsRegex(absl::StrCat("State:.[", state,
+ "]\\s+\\(\\w+\\)")));
+}
+
+// Run callbacks while a subprocess is running, zombied, and/or exited.
+PosixError WithSubprocess(SubprocessCallback const& running,
+ SubprocessCallback const& zombied,
+ SubprocessCallback const& exited) {
+ int pipe_fds[2] = {};
+ if (pipe(pipe_fds) < 0) {
+ return PosixError(errno, "pipe");
+ }
+
+ int child_pid = fork();
+ if (child_pid < 0) {
+ return PosixError(errno, "fork");
+ }
+
+ if (child_pid == 0) {
+ close(pipe_fds[0]); // Close the read end.
+ const DisableSave ds; // Timing issues.
+
+ // Write to the pipe to tell it we're ready.
+ char buf = 'a';
+ int res = 0;
+ res = WriteFd(pipe_fds[1], &buf, sizeof(buf));
+ TEST_CHECK_MSG(res == sizeof(buf), "Write failure in subprocess");
+
+ while (true) {
+ SleepSafe(absl::Milliseconds(100));
+ }
+ __builtin_unreachable();
+ }
+
+ close(pipe_fds[1]); // Close the write end.
+
+ int status = 0;
+ auto wait_cleanup = Cleanup([child_pid, &status] {
+ EXPECT_THAT(waitpid(child_pid, &status, 0), SyscallSucceeds());
+ });
+ auto kill_cleanup = Cleanup([child_pid] {
+ EXPECT_THAT(kill(child_pid, SIGKILL), SyscallSucceeds());
+ });
+
+ // Wait for the child.
+ char buf = 0;
+ int res = ReadFd(pipe_fds[0], &buf, sizeof(buf));
+ if (res < 0) {
+ return PosixError(errno, "Read from pipe");
+ } else if (res == 0) {
+ return PosixError(EPIPE, "Unable to read from pipe: EOF");
+ }
+
+ if (running) {
+ // The first arg, RSD, refers to a "running process", or a process with a
+ // state of Running (R), Interruptable Sleep (S) or Uninterruptable
+ // Sleep (D).
+ CompareProcessState("RSD", child_pid);
+ RETURN_IF_ERRNO(running(child_pid));
+ }
+
+ // Kill the process.
+ kill_cleanup.Release()();
+ siginfo_t info;
+ // Wait until the child process has exited (WEXITED flag) but don't
+ // reap the child (WNOWAIT flag).
+ waitid(P_PID, child_pid, &info, WNOWAIT | WEXITED);
+
+ if (zombied) {
+ // Arg of "Z" refers to a Zombied Process.
+ CompareProcessState("Z", child_pid);
+ RETURN_IF_ERRNO(zombied(child_pid));
+ }
+
+ // Wait on the process.
+ wait_cleanup.Release()();
+ // If the process is reaped, then then this should return
+ // with ECHILD.
+ EXPECT_THAT(waitpid(child_pid, &status, WNOHANG),
+ SyscallFailsWithErrno(ECHILD));
+
+ if (exited) {
+ RETURN_IF_ERRNO(exited(child_pid));
+ }
+
+ return NoError();
+}
+
+// Access the file returned by name when a subprocess is running.
+PosixError AccessWhileRunning(std::function<std::string(int pid)> name, int flags,
+ std::function<void(int fd)> access) {
+ FileDescriptor fd;
+ return WithSubprocess(
+ [&](int pid) -> PosixError {
+ // Running.
+ ASSIGN_OR_RETURN_ERRNO(fd, Open(name(pid), flags));
+
+ access(fd.get());
+ return NoError();
+ },
+ nullptr, nullptr);
+}
+
+// Access the file returned by name when the a subprocess is zombied.
+PosixError AccessWhileZombied(std::function<std::string(int pid)> name, int flags,
+ std::function<void(int fd)> access) {
+ FileDescriptor fd;
+ return WithSubprocess(
+ [&](int pid) -> PosixError {
+ // Running.
+ ASSIGN_OR_RETURN_ERRNO(fd, Open(name(pid), flags));
+ return NoError();
+ },
+ [&](int pid) -> PosixError {
+ // Zombied.
+ access(fd.get());
+ return NoError();
+ },
+ nullptr);
+}
+
+// Access the file returned by name when the a subprocess is exited.
+PosixError AccessWhileExited(std::function<std::string(int pid)> name, int flags,
+ std::function<void(int fd)> access) {
+ FileDescriptor fd;
+ return WithSubprocess(
+ [&](int pid) -> PosixError {
+ // Running.
+ ASSIGN_OR_RETURN_ERRNO(fd, Open(name(pid), flags));
+ return NoError();
+ },
+ nullptr,
+ [&](int pid) -> PosixError {
+ // Exited.
+ access(fd.get());
+ return NoError();
+ });
+}
+
+// ReadFd(fd=/proc/PID/basename) while PID is running.
+int ReadWhileRunning(std::string const& basename, void* buf, size_t count) {
+ int ret = 0;
+ int err = 0;
+ EXPECT_NO_ERRNO(AccessWhileRunning(
+ [&](int pid) -> std::string {
+ return absl::StrCat("/proc/", pid, "/", basename);
+ },
+ O_RDONLY,
+ [&](int fd) {
+ ret = ReadFd(fd, buf, count);
+ err = errno;
+ }));
+ errno = err;
+ return ret;
+}
+
+// ReadFd(fd=/proc/PID/basename) while PID is zombied.
+int ReadWhileZombied(std::string const& basename, void* buf, size_t count) {
+ int ret = 0;
+ int err = 0;
+ EXPECT_NO_ERRNO(AccessWhileZombied(
+ [&](int pid) -> std::string {
+ return absl::StrCat("/proc/", pid, "/", basename);
+ },
+ O_RDONLY,
+ [&](int fd) {
+ ret = ReadFd(fd, buf, count);
+ err = errno;
+ }));
+ errno = err;
+ return ret;
+}
+
+// ReadFd(fd=/proc/PID/basename) while PID is exited.
+int ReadWhileExited(std::string const& basename, void* buf, size_t count) {
+ int ret = 0;
+ int err = 0;
+ EXPECT_NO_ERRNO(AccessWhileExited(
+ [&](int pid) -> std::string {
+ return absl::StrCat("/proc/", pid, "/", basename);
+ },
+ O_RDONLY,
+ [&](int fd) {
+ ret = ReadFd(fd, buf, count);
+ err = errno;
+ }));
+ errno = err;
+ return ret;
+}
+
+// readlinkat(fd=/proc/PID/, basename) while PID is running.
+int ReadlinkWhileRunning(std::string const& basename, char* buf, size_t count) {
+ int ret = 0;
+ int err = 0;
+ EXPECT_NO_ERRNO(AccessWhileRunning(
+ [&](int pid) -> std::string { return absl::StrCat("/proc/", pid, "/"); },
+ O_DIRECTORY,
+ [&](int fd) {
+ ret = readlinkat(fd, basename.c_str(), buf, count);
+ err = errno;
+ }));
+ errno = err;
+ return ret;
+}
+
+// readlinkat(fd=/proc/PID/, basename) while PID is zombied.
+int ReadlinkWhileZombied(std::string const& basename, char* buf, size_t count) {
+ int ret = 0;
+ int err = 0;
+ EXPECT_NO_ERRNO(AccessWhileZombied(
+ [&](int pid) -> std::string { return absl::StrCat("/proc/", pid, "/"); },
+ O_DIRECTORY,
+ [&](int fd) {
+ ret = readlinkat(fd, basename.c_str(), buf, count);
+ err = errno;
+ }));
+ errno = err;
+ return ret;
+}
+
+// readlinkat(fd=/proc/PID/, basename) while PID is exited.
+int ReadlinkWhileExited(std::string const& basename, char* buf, size_t count) {
+ int ret = 0;
+ int err = 0;
+ EXPECT_NO_ERRNO(AccessWhileExited(
+ [&](int pid) -> std::string { return absl::StrCat("/proc/", pid, "/"); },
+ O_DIRECTORY,
+ [&](int fd) {
+ ret = readlinkat(fd, basename.c_str(), buf, count);
+ err = errno;
+ }));
+ errno = err;
+ return ret;
+}
+
+TEST(ProcSelfTest, IsThreadGroupLeader) {
+ ScopedThread([] {
+ const pid_t tgid = getpid();
+ const pid_t tid = syscall(SYS_gettid);
+ EXPECT_NE(tgid, tid);
+ auto link = ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/self"));
+ EXPECT_EQ(link, absl::StrCat(tgid));
+ });
+}
+
+TEST(ProcThreadSelfTest, Basic) {
+ const pid_t tgid = getpid();
+ const pid_t tid = syscall(SYS_gettid);
+ EXPECT_EQ(tgid, tid);
+ auto link_threadself =
+ ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/thread-self"));
+ EXPECT_EQ(link_threadself, absl::StrCat(tgid, "/task/", tid));
+ // Just read one file inside thread-self to ensure that the link is valid.
+ auto link_threadself_exe =
+ ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/thread-self/exe"));
+ auto link_procself_exe =
+ ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/self/exe"));
+ EXPECT_EQ(link_threadself_exe, link_procself_exe);
+}
+
+TEST(ProcThreadSelfTest, Thread) {
+ ScopedThread([] {
+ const pid_t tgid = getpid();
+ const pid_t tid = syscall(SYS_gettid);
+ EXPECT_NE(tgid, tid);
+ auto link_threadself =
+ ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/thread-self"));
+
+ EXPECT_EQ(link_threadself, absl::StrCat(tgid, "/task/", tid));
+ // Just read one file inside thread-self to ensure that the link is valid.
+ auto link_threadself_exe =
+ ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/thread-self/exe"));
+ auto link_procself_exe =
+ ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/self/exe"));
+ EXPECT_EQ(link_threadself_exe, link_procself_exe);
+ // A thread should not have "/proc/<tid>/task".
+ struct stat s;
+ EXPECT_THAT(stat("/proc/thread-self/task", &s),
+ SyscallFailsWithErrno(ENOENT));
+ });
+}
+
+// Returns the /proc/PID/maps entry for the MAP_PRIVATE | MAP_ANONYMOUS mapping
+// m with start address addr and length len.
+std::string AnonymousMapsEntry(uintptr_t addr, size_t len, int prot) {
+ return absl::StrCat(absl::Hex(addr, absl::PadSpec::kZeroPad8), "-",
+ absl::Hex(addr + len, absl::PadSpec::kZeroPad8), " ",
+ prot & PROT_READ ? "r" : "-",
+ prot & PROT_WRITE ? "w" : "-",
+ prot & PROT_EXEC ? "x" : "-", "p 00000000 00:00 0 ");
+}
+
+std::string AnonymousMapsEntryForMapping(const Mapping& m, int prot) {
+ return AnonymousMapsEntry(m.addr(), m.len(), prot);
+}
+
+PosixErrorOr<std::map<uint64_t, uint64_t>> ReadProcSelfAuxv() {
+ std::string auxv_file;
+ RETURN_IF_ERRNO(GetContents("/proc/self/auxv", &auxv_file));
+ const Elf64_auxv_t* auxv_data =
+ reinterpret_cast<const Elf64_auxv_t*>(auxv_file.data());
+ std::map<uint64_t, uint64_t> auxv_entries;
+ for (int i = 0; auxv_data[i].a_type != AT_NULL; i++) {
+ auto a_type = auxv_data[i].a_type;
+ EXPECT_EQ(0, auxv_entries.count(a_type)) << "a_type: " << a_type;
+ auxv_entries.emplace(a_type, auxv_data[i].a_un.a_val);
+ }
+ return auxv_entries;
+}
+
+TEST(ProcSelfAuxv, EntryPresence) {
+ auto auxv_entries = ASSERT_NO_ERRNO_AND_VALUE(ReadProcSelfAuxv());
+
+ EXPECT_EQ(auxv_entries.count(AT_ENTRY), 1);
+ EXPECT_EQ(auxv_entries.count(AT_PHDR), 1);
+ EXPECT_EQ(auxv_entries.count(AT_PHENT), 1);
+ EXPECT_EQ(auxv_entries.count(AT_PHNUM), 1);
+ EXPECT_EQ(auxv_entries.count(AT_BASE), 1);
+ EXPECT_EQ(auxv_entries.count(AT_CLKTCK), 1);
+ EXPECT_EQ(auxv_entries.count(AT_RANDOM), 1);
+ EXPECT_EQ(auxv_entries.count(AT_EXECFN), 1);
+ EXPECT_EQ(auxv_entries.count(AT_PAGESZ), 1);
+ EXPECT_EQ(auxv_entries.count(AT_SYSINFO_EHDR), 1);
+}
+
+TEST(ProcSelfAuxv, EntryValues) {
+ auto proc_auxv = ASSERT_NO_ERRNO_AND_VALUE(ReadProcSelfAuxv());
+
+ // We need to find the ELF auxiliary vector. The section of memory pointed to
+ // by envp contains some pointers to non-null pointers, followed by a single
+ // pointer to a null pointer, followed by the auxiliary vector.
+ char** envpi = environ;
+ while (*envpi) {
+ ++envpi;
+ }
+
+ const Elf64_auxv_t* envp_auxv =
+ reinterpret_cast<const Elf64_auxv_t*>(envpi + 1);
+ int i;
+ for (i = 0; envp_auxv[i].a_type != AT_NULL; i++) {
+ auto a_type = envp_auxv[i].a_type;
+ EXPECT_EQ(proc_auxv.count(a_type), 1);
+ EXPECT_EQ(proc_auxv[a_type], envp_auxv[i].a_un.a_val)
+ << "a_type: " << a_type;
+ }
+ EXPECT_EQ(i, proc_auxv.size());
+}
+
+// Just open and read /proc/self/maps, check that we can find [stack]
+TEST(ProcSelfMaps, Basic) {
+ auto proc_self_maps =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/maps"));
+
+ std::vector<std::string> strings = absl::StrSplit(proc_self_maps, '\n');
+ std::vector<std::string> stacks;
+ // Make sure there's a stack in there.
+ for (const auto& str : strings) {
+ if (str.find("[stack]") != std::string::npos) {
+ stacks.push_back(str);
+ }
+ }
+ ASSERT_EQ(1, stacks.size()) << "[stack] not found in: " << proc_self_maps;
+ // Linux pads to 73 characters then we add 7.
+ EXPECT_EQ(80, stacks[0].length());
+}
+
+TEST(ProcSelfMaps, Map1) {
+ Mapping mapping =
+ ASSERT_NO_ERRNO_AND_VALUE(MmapAnon(kPageSize, PROT_READ, MAP_PRIVATE));
+ auto proc_self_maps =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/maps"));
+ std::vector<std::string> strings = absl::StrSplit(proc_self_maps, '\n');
+ std::vector<std::string> addrs;
+ // Make sure if is listed.
+ for (const auto& str : strings) {
+ if (str == AnonymousMapsEntryForMapping(mapping, PROT_READ)) {
+ addrs.push_back(str);
+ }
+ }
+ ASSERT_EQ(1, addrs.size());
+}
+
+TEST(ProcSelfMaps, Map2) {
+ // NOTE: The permissions must be different or the pages will get merged.
+ Mapping map1 = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_EXEC, MAP_PRIVATE));
+ Mapping map2 =
+ ASSERT_NO_ERRNO_AND_VALUE(MmapAnon(kPageSize, PROT_WRITE, MAP_PRIVATE));
+
+ auto proc_self_maps =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/maps"));
+ std::vector<std::string> strings = absl::StrSplit(proc_self_maps, '\n');
+ std::vector<std::string> addrs;
+ // Make sure if is listed.
+ for (const auto& str : strings) {
+ if (str == AnonymousMapsEntryForMapping(map1, PROT_READ | PROT_EXEC)) {
+ addrs.push_back(str);
+ }
+ }
+ ASSERT_EQ(1, addrs.size());
+ addrs.clear();
+ for (const auto& str : strings) {
+ if (str == AnonymousMapsEntryForMapping(map2, PROT_WRITE)) {
+ addrs.push_back(str);
+ }
+ }
+ ASSERT_EQ(1, addrs.size());
+}
+
+TEST(ProcSelfMaps, MapUnmap) {
+ Mapping map1 = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kPageSize, PROT_READ | PROT_EXEC, MAP_PRIVATE));
+ Mapping map2 =
+ ASSERT_NO_ERRNO_AND_VALUE(MmapAnon(kPageSize, PROT_WRITE, MAP_PRIVATE));
+
+ auto proc_self_maps =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/maps"));
+ std::vector<std::string> strings = absl::StrSplit(proc_self_maps, '\n');
+ std::vector<std::string> addrs;
+ // Make sure if is listed.
+ for (const auto& str : strings) {
+ if (str == AnonymousMapsEntryForMapping(map1, PROT_READ | PROT_EXEC)) {
+ addrs.push_back(str);
+ }
+ }
+ ASSERT_EQ(1, addrs.size()) << proc_self_maps;
+ addrs.clear();
+ for (const auto& str : strings) {
+ if (str == AnonymousMapsEntryForMapping(map2, PROT_WRITE)) {
+ addrs.push_back(str);
+ }
+ }
+ ASSERT_EQ(1, addrs.size());
+
+ map2.reset();
+
+ // Read it again.
+ proc_self_maps = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/maps"));
+ strings = absl::StrSplit(proc_self_maps, '\n');
+ // First entry should be there.
+ addrs.clear();
+ for (const auto& str : strings) {
+ if (str == AnonymousMapsEntryForMapping(map1, PROT_READ | PROT_EXEC)) {
+ addrs.push_back(str);
+ }
+ }
+ ASSERT_EQ(1, addrs.size());
+ addrs.clear();
+ // But not the second.
+ for (const auto& str : strings) {
+ if (str == AnonymousMapsEntryForMapping(map2, PROT_WRITE)) {
+ addrs.push_back(str);
+ }
+ }
+ ASSERT_EQ(0, addrs.size());
+}
+
+TEST(ProcSelfMaps, Mprotect) {
+ if (!IsRunningOnGvisor()) {
+ // FIXME: Linux's mprotect() sometimes fails to merge VMAs in this
+ // case.
+ LOG(WARNING) << "Skipping test on Linux";
+ return;
+ }
+
+ // Reserve 5 pages of address space.
+ Mapping m = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(5 * kPageSize, PROT_NONE, MAP_PRIVATE));
+
+ // Change the permissions on the middle 3 pages. (The first and last pages may
+ // be merged with other vmas on either side, so they aren't tested directly;
+ // they just ensure that the middle 3 pages are bracketed by VMAs with
+ // incompatible permissions.)
+ ASSERT_THAT(mprotect(reinterpret_cast<void*>(m.addr() + kPageSize),
+ 3 * kPageSize, PROT_READ),
+ SyscallSucceeds());
+
+ // Check that the middle 3 pages make up a single VMA.
+ auto proc_self_maps =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/maps"));
+ std::vector<std::string> strings = absl::StrSplit(proc_self_maps, '\n');
+ EXPECT_THAT(strings, Contains(AnonymousMapsEntry(m.addr() + kPageSize,
+ 3 * kPageSize, PROT_READ)));
+
+ // Change the permissions on the middle page only.
+ ASSERT_THAT(mprotect(reinterpret_cast<void*>(m.addr() + 2 * kPageSize),
+ kPageSize, PROT_READ | PROT_WRITE),
+ SyscallSucceeds());
+
+ // Check that the single VMA has been split into 3 VMAs.
+ proc_self_maps = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/maps"));
+ strings = absl::StrSplit(proc_self_maps, '\n');
+ EXPECT_THAT(
+ strings,
+ IsSupersetOf(
+ {AnonymousMapsEntry(m.addr() + kPageSize, kPageSize, PROT_READ),
+ AnonymousMapsEntry(m.addr() + 2 * kPageSize, kPageSize,
+ PROT_READ | PROT_WRITE),
+ AnonymousMapsEntry(m.addr() + 3 * kPageSize, kPageSize,
+ PROT_READ)}));
+
+ // Change the permissions on the middle page back.
+ ASSERT_THAT(mprotect(reinterpret_cast<void*>(m.addr() + 2 * kPageSize),
+ kPageSize, PROT_READ),
+ SyscallSucceeds());
+
+ // Check that the 3 VMAs have been merged back into a single VMA.
+ proc_self_maps = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/maps"));
+ strings = absl::StrSplit(proc_self_maps, '\n');
+ EXPECT_THAT(strings, Contains(AnonymousMapsEntry(m.addr() + kPageSize,
+ 3 * kPageSize, PROT_READ)));
+}
+
+TEST(ProcSelfFd, OpenFd) {
+ int pipe_fds[2];
+ ASSERT_THAT(pipe2(pipe_fds, O_CLOEXEC), SyscallSucceeds());
+
+ // Reopen the write end.
+ const std::string path = absl::StrCat("/proc/self/fd/", pipe_fds[1]);
+ const FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(path, O_WRONLY));
+
+ // Ensure that a read/write works.
+ const std::string data = "hello";
+ std::unique_ptr<char[]> buffer(new char[data.size()]);
+ EXPECT_THAT(write(fd.get(), data.c_str(), data.size()),
+ SyscallSucceedsWithValue(5));
+ EXPECT_THAT(read(pipe_fds[0], buffer.get(), data.size()),
+ SyscallSucceedsWithValue(5));
+ EXPECT_EQ(strncmp(buffer.get(), data.c_str(), data.size()), 0);
+
+ // Cleanup.
+ ASSERT_THAT(close(pipe_fds[0]), SyscallSucceeds());
+ ASSERT_THAT(close(pipe_fds[1]), SyscallSucceeds());
+}
+
+TEST(ProcSelfFdInfo, CorrectFds) {
+ // Make sure there is at least one open file.
+ auto f = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
+ const FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(f.path(), O_RDONLY));
+
+ // Get files in /proc/self/fd.
+ auto fd_files = ASSERT_NO_ERRNO_AND_VALUE(ListDir("/proc/self/fd", false));
+
+ // Get files in /proc/self/fdinfo.
+ auto fdinfo_files =
+ ASSERT_NO_ERRNO_AND_VALUE(ListDir("/proc/self/fdinfo", false));
+
+ // They should contain the same fds.
+ EXPECT_THAT(fd_files, UnorderedElementsAreArray(fdinfo_files));
+
+ // Both should contain fd.
+ auto fd_s = absl::StrCat(fd.get());
+ EXPECT_THAT(fd_files, Contains(fd_s));
+}
+
+TEST(ProcSelfFdInfo, Flags) {
+ std::string path = NewTempAbsPath();
+
+ // Create file here with O_CREAT to test that O_CREAT does not appear in
+ // fdinfo flags.
+ int flags = O_CREAT | O_RDWR | O_APPEND | O_CLOEXEC;
+ const FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(path, flags, 0644));
+
+ // Automatically delete path.
+ TempPath temp_path(path);
+
+ // O_CREAT does not appear in fdinfo flags.
+ flags &= ~O_CREAT;
+
+ // O_LARGEFILE always appears (on x86_64).
+ flags |= kOLargeFile;
+
+ auto fd_info = ASSERT_NO_ERRNO_AND_VALUE(
+ GetContents(absl::StrCat("/proc/self/fdinfo/", fd.get())));
+ EXPECT_THAT(fd_info, HasSubstr(absl::StrFormat("flags:\t%#o", flags)));
+}
+
+TEST(ProcSelfExe, Absolute) {
+ auto exe = ASSERT_NO_ERRNO_AND_VALUE(
+ ReadLink(absl::StrCat("/proc/", getpid(), "/exe")));
+ EXPECT_EQ(exe[0], '/');
+}
+
+// Sanity check for /proc/cpuinfo fields that must be present.
+TEST(ProcCpuinfo, RequiredFieldsArePresent) {
+ std::string proc_cpuinfo = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/cpuinfo"));
+ ASSERT_FALSE(proc_cpuinfo.empty());
+ std::vector<std::string> cpuinfo_fields = absl::StrSplit(proc_cpuinfo, '\n');
+
+ // This list of "required" fields is taken from reading the file
+ // arch/x86/kernel/cpu/proc.c and seeing which fields will be unconditionally
+ // printed by the kernel.
+ static const char* required_fields[] = {
+ "processor",
+ "vendor_id",
+ "cpu family",
+ "model\t\t:",
+ "model name",
+ "stepping",
+ "cpu MHz",
+ "fpu\t\t:",
+ "fpu_exception",
+ "cpuid level",
+ "wp",
+ "bogomips",
+ "clflush size",
+ "cache_alignment",
+ "address sizes",
+ "power management",
+ };
+
+ // Check that the usual fields are there. We don't really care about the
+ // contents.
+ for (const std::string& field : required_fields) {
+ EXPECT_THAT(proc_cpuinfo, HasSubstr(field));
+ }
+}
+
+// Sanity checks that uptime is present.
+TEST(ProcUptime, IsPresent) {
+ std::string proc_uptime = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/uptime"));
+ ASSERT_FALSE(proc_uptime.empty());
+ std::vector<std::string> uptime_parts = absl::StrSplit(proc_uptime, ' ');
+
+ // Parse once.
+ double uptime0, uptime1, idletime0, idletime1;
+ ASSERT_TRUE(absl::SimpleAtod(uptime_parts[0], &uptime0));
+ ASSERT_TRUE(absl::SimpleAtod(uptime_parts[1], &idletime0));
+
+ // Sleep for one second.
+ absl::SleepFor(absl::Seconds(1));
+
+ // Parse again.
+ proc_uptime = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/uptime"));
+ ASSERT_FALSE(proc_uptime.empty());
+ uptime_parts = absl::StrSplit(proc_uptime, ' ');
+ ASSERT_TRUE(absl::SimpleAtod(uptime_parts[0], &uptime1));
+ ASSERT_TRUE(absl::SimpleAtod(uptime_parts[1], &idletime1));
+
+ // Sanity check.
+ //
+ // We assert that between 0.99 and 59.99 seconds have passed. If more than a
+ // minute has passed, then we must be executing really, really slowly.
+ EXPECT_GE(uptime0, 0.0);
+ EXPECT_GE(idletime0, 0.0);
+ EXPECT_GT(uptime1, uptime0);
+ EXPECT_GE(uptime1, uptime0 + 0.99);
+ EXPECT_LE(uptime1, uptime0 + 59.99);
+ EXPECT_GE(idletime1, idletime0);
+}
+
+TEST(ProcMeminfo, ContainsBasicFields) {
+ std::string proc_meminfo = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/meminfo"));
+ EXPECT_THAT(proc_meminfo, AllOf(ContainsRegex(R"(MemTotal:\s+[0-9]+ kB)"),
+ ContainsRegex(R"(MemFree:\s+[0-9]+ kB)")));
+}
+
+TEST(ProcStat, ContainsBasicFields) {
+ std::string proc_stat = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/stat"));
+
+ std::vector<std::string> names;
+ for (auto const& line : absl::StrSplit(proc_stat, '\n')) {
+ std::vector<std::string> fields =
+ absl::StrSplit(line, ' ', absl::SkipWhitespace());
+ if (fields.empty()) {
+ continue;
+ }
+ names.push_back(fields[0]);
+ }
+
+ EXPECT_THAT(names,
+ IsSupersetOf({"cpu", "intr", "ctxt", "btime", "processes",
+ "procs_running", "procs_blocked", "softirq"}));
+}
+
+TEST(ProcStat, EndsWithNewline) {
+ std::string proc_stat = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/stat"));
+ EXPECT_EQ(proc_stat.back(), '\n');
+}
+
+TEST(ProcStat, Fields) {
+ std::string proc_stat = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/stat"));
+
+ std::vector<std::string> names;
+ for (auto const& line : absl::StrSplit(proc_stat, '\n')) {
+ std::vector<std::string> fields =
+ absl::StrSplit(line, ' ', absl::SkipWhitespace());
+ if (fields.empty()) {
+ continue;
+ }
+
+ if (absl::StartsWith(fields[0], "cpu")) {
+ // As of Linux 3.11, each CPU entry has 10 fields, plus the name.
+ EXPECT_GE(fields.size(), 11) << proc_stat;
+ } else if (fields[0] == "ctxt") {
+ // Single field.
+ EXPECT_EQ(fields.size(), 2) << proc_stat;
+ } else if (fields[0] == "btime") {
+ // Single field.
+ EXPECT_EQ(fields.size(), 2) << proc_stat;
+ } else if (fields[0] == "itime") {
+ // Single field.
+ ASSERT_EQ(fields.size(), 2) << proc_stat;
+ // This is the only floating point field.
+ double val;
+ EXPECT_TRUE(absl::SimpleAtod(fields[1], &val)) << proc_stat;
+ continue;
+ } else if (fields[0] == "processes") {
+ // Single field.
+ EXPECT_EQ(fields.size(), 2) << proc_stat;
+ } else if (fields[0] == "procs_running") {
+ // Single field.
+ EXPECT_EQ(fields.size(), 2) << proc_stat;
+ } else if (fields[0] == "procs_blocked") {
+ // Single field.
+ EXPECT_EQ(fields.size(), 2) << proc_stat;
+ } else if (fields[0] == "softirq") {
+ // As of Linux 3.11, there are 10 softirqs. 12 fields for name + total.
+ EXPECT_GE(fields.size(), 12) << proc_stat;
+ }
+
+ // All fields besides itime are valid base 10 numbers.
+ for (size_t i = 1; i < fields.size(); i++) {
+ uint64_t val;
+ EXPECT_TRUE(absl::SimpleAtoi(fields[i], &val)) << proc_stat;
+ }
+ }
+}
+
+TEST(ProcLoadavg, EndsWithNewline) {
+ std::string proc_loadvg = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/loadavg"));
+ EXPECT_EQ(proc_loadvg.back(), '\n');
+}
+
+TEST(ProcLoadavg, Fields) {
+ std::string proc_loadvg = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/loadavg"));
+ std::vector<std::string> lines = absl::StrSplit(proc_loadvg, '\n');
+
+ // Single line.
+ EXPECT_EQ(lines.size(), 2) << proc_loadvg;
+
+ std::vector<std::string> fields =
+ absl::StrSplit(lines[0], absl::ByAnyChar(" /"), absl::SkipWhitespace());
+
+ // Six fields.
+ EXPECT_EQ(fields.size(), 6) << proc_loadvg;
+
+ double val;
+ uint64_t val2;
+ // First three fields are floating point numbers.
+ EXPECT_TRUE(absl::SimpleAtod(fields[0], &val)) << proc_loadvg;
+ EXPECT_TRUE(absl::SimpleAtod(fields[1], &val)) << proc_loadvg;
+ EXPECT_TRUE(absl::SimpleAtod(fields[2], &val)) << proc_loadvg;
+ // Rest of the fields are valid base 10 numbers.
+ EXPECT_TRUE(absl::SimpleAtoi(fields[3], &val2)) << proc_loadvg;
+ EXPECT_TRUE(absl::SimpleAtoi(fields[4], &val2)) << proc_loadvg;
+ EXPECT_TRUE(absl::SimpleAtoi(fields[5], &val2)) << proc_loadvg;
+}
+
+// NOTE: Tests in priority.cc also check certain priority related fields in
+// /proc/self/stat.
+
+class ProcPidStatTest : public ::testing::TestWithParam<std::string> {};
+
+TEST_P(ProcPidStatTest, HasBasicFields) {
+ std::string proc_pid_stat = ASSERT_NO_ERRNO_AND_VALUE(
+ GetContents(absl::StrCat("/proc/", GetParam(), "/stat")));
+
+ ASSERT_FALSE(proc_pid_stat.empty());
+ std::vector<std::string> fields = absl::StrSplit(proc_pid_stat, ' ');
+ ASSERT_GE(fields.size(), 24);
+ EXPECT_EQ(absl::StrCat(getpid()), fields[0]);
+ // fields[1] is the thread name.
+ EXPECT_EQ("R", fields[2]); // task state
+ EXPECT_EQ(absl::StrCat(getppid()), fields[3]);
+
+ uint64_t vss;
+ ASSERT_TRUE(absl::SimpleAtoi(fields[22], &vss));
+ EXPECT_GT(vss, 0);
+
+ uint64_t rss;
+ ASSERT_TRUE(absl::SimpleAtoi(fields[23], &rss));
+ EXPECT_GT(rss, 0);
+}
+
+INSTANTIATE_TEST_CASE_P(SelfAndNumericPid, ProcPidStatTest,
+ ::testing::Values("self", absl::StrCat(getpid())));
+
+using ProcPidStatmTest = ::testing::TestWithParam<std::string>;
+
+TEST_P(ProcPidStatmTest, HasBasicFields) {
+ std::string proc_pid_statm = ASSERT_NO_ERRNO_AND_VALUE(
+ GetContents(absl::StrCat("/proc/", GetParam(), "/statm")));
+ ASSERT_FALSE(proc_pid_statm.empty());
+ std::vector<std::string> fields = absl::StrSplit(proc_pid_statm, ' ');
+ ASSERT_GE(fields.size(), 7);
+
+ uint64_t vss;
+ ASSERT_TRUE(absl::SimpleAtoi(fields[0], &vss));
+ EXPECT_GT(vss, 0);
+
+ uint64_t rss;
+ ASSERT_TRUE(absl::SimpleAtoi(fields[1], &rss));
+ EXPECT_GT(rss, 0);
+}
+
+INSTANTIATE_TEST_CASE_P(SelfAndNumericPid, ProcPidStatmTest,
+ ::testing::Values("self", absl::StrCat(getpid())));
+
+PosixErrorOr<uint64_t> CurrentRSS() {
+ ASSIGN_OR_RETURN_ERRNO(auto proc_self_stat, GetContents("/proc/self/stat"));
+ if (proc_self_stat.empty()) {
+ return PosixError(EINVAL, "empty /proc/self/stat");
+ }
+
+ std::vector<std::string> fields = absl::StrSplit(proc_self_stat, ' ');
+ if (fields.size() < 24) {
+ return PosixError(
+ EINVAL,
+ absl::StrCat("/proc/self/stat has too few fields: ", proc_self_stat));
+ }
+
+ uint64_t rss;
+ if (!absl::SimpleAtoi(fields[23], &rss)) {
+ return PosixError(
+ EINVAL, absl::StrCat("/proc/self/stat RSS field is not a number: ",
+ fields[23]));
+ }
+
+ // RSS is given in number of pages.
+ return rss * kPageSize;
+}
+
+// The size of mapping created by MapPopulateRSS.
+constexpr uint64_t kMappingSize = 100 << 20;
+
+// Tolerance on RSS comparisons to account for background thread mappings,
+// reclaimed pages, newly faulted pages, etc.
+constexpr uint64_t kRSSTolerance = 5 << 20;
+
+// Capture RSS before and after an anonymous mapping with passed prot.
+void MapPopulateRSS(int prot, uint64_t* before, uint64_t* after) {
+ *before = ASSERT_NO_ERRNO_AND_VALUE(CurrentRSS());
+
+ // N.B. The kernel asynchronously accumulates per-task RSS counters into the
+ // mm RSS, which is exposed by /proc/PID/stat. Task exit is a synchronization
+ // point (kernel/exit.c:do_exit -> sync_mm_rss), so perform the mapping on
+ // another thread to ensure it is reflected in RSS after the thread exits.
+ Mapping mapping;
+ ScopedThread t([&mapping, prot] {
+ mapping = ASSERT_NO_ERRNO_AND_VALUE(
+ MmapAnon(kMappingSize, prot, MAP_PRIVATE | MAP_POPULATE));
+ });
+ t.Join();
+
+ *after = ASSERT_NO_ERRNO_AND_VALUE(CurrentRSS());
+}
+
+// TODO: Test for PROT_READ + MAP_POPULATE anonymous mappings. Their
+// semantics are more subtle:
+//
+// Small pages -> Zero page mapped, not counted in RSS
+// (mm/memory.c:do_anonymous_page).
+//
+// Huge pages (THP enabled, use_zero_page=0) -> Pages committed
+// (mm/memory.c:__handle_mm_fault -> create_huge_pmd).
+//
+// Huge pages (THP enabled, use_zero_page=1) -> Zero page mapped, not counted in
+// RSS (mm/huge_memory.c:do_huge_pmd_anonymous_page).
+
+// PROT_WRITE + MAP_POPULATE anonymous mappings are always committed.
+TEST(ProcSelfStat, PopulateWriteRSS) {
+ uint64_t before, after;
+ MapPopulateRSS(PROT_READ | PROT_WRITE, &before, &after);
+
+ // Mapping is committed.
+ EXPECT_NEAR(before + kMappingSize, after, kRSSTolerance);
+}
+
+// PROT_NONE + MAP_POPULATE anonymous mappings are never committed.
+TEST(ProcSelfStat, PopulateNoneRSS) {
+ uint64_t before, after;
+ MapPopulateRSS(PROT_NONE, &before, &after);
+
+ // Mapping not committed.
+ EXPECT_NEAR(before, after, kRSSTolerance);
+}
+
+// Returns the calling thread's name.
+PosixErrorOr<std::string> ThreadName() {
+ // "The buffer should allow space for up to 16 bytes; the returned std::string
+ // will be null-terminated if it is shorter than that." - prctl(2). But we
+ // always want the thread name to be null-terminated.
+ char thread_name[17];
+ int rc = prctl(PR_GET_NAME, thread_name, 0, 0, 0);
+ MaybeSave();
+ if (rc < 0) {
+ return PosixError(errno, "prctl(PR_GET_NAME)");
+ }
+ thread_name[16] = '\0';
+ return std::string(thread_name);
+}
+
+// Parses the contents of a /proc/[pid]/status file into a collection of
+// key-value pairs.
+PosixErrorOr<std::map<std::string, std::string>> ParseProcStatus(
+ absl::string_view status_str) {
+ std::map<std::string, std::string> fields;
+ for (absl::string_view const line :
+ absl::StrSplit(status_str, '\n', absl::SkipWhitespace())) {
+ const std::pair<absl::string_view, absl::string_view> kv =
+ absl::StrSplit(line, absl::MaxSplits(":\t", 1));
+ if (kv.first.empty()) {
+ return PosixError(
+ EINVAL, absl::StrCat("failed to parse key in line \"", line, "\""));
+ }
+ std::string key(kv.first);
+ if (fields.count(key)) {
+ return PosixError(EINVAL,
+ absl::StrCat("duplicate key \"", kv.first, "\""));
+ }
+ std::string value(kv.second);
+ absl::StripLeadingAsciiWhitespace(&value);
+ fields.emplace(std::move(key), std::move(value));
+ }
+ return fields;
+}
+
+TEST(ParseProcStatusTest, ParsesSimpleStatusFileWithMixedWhitespaceCorrectly) {
+ EXPECT_THAT(
+ ParseProcStatus(
+ "Name:\tinit\nState:\tS (sleeping)\nCapEff:\t 0000001fffffffff\n"),
+ IsPosixErrorOkAndHolds(UnorderedElementsAre(
+ Pair("Name", "init"), Pair("State", "S (sleeping)"),
+ Pair("CapEff", "0000001fffffffff"))));
+}
+
+TEST(ParseProcStatusTest, DetectsDuplicateKeys) {
+ auto proc_status_or = ParseProcStatus("Name:\tfoo\nName:\tfoo\n");
+ EXPECT_THAT(proc_status_or,
+ PosixErrorIs(EINVAL, ::testing::StrEq("duplicate key \"Name\"")));
+}
+
+TEST(ParseProcStatusTest, DetectsMissingTabs) {
+ EXPECT_THAT(ParseProcStatus("Name:foo\nPid: 1\n"),
+ IsPosixErrorOkAndHolds(UnorderedElementsAre(Pair("Name:foo", ""),
+ Pair("Pid: 1", ""))));
+}
+
+TEST(ProcPidStatusTest, HasBasicFields) {
+ // Do this on a separate thread since we want tgid != tid.
+ ScopedThread([] {
+ const pid_t tgid = getpid();
+ const pid_t tid = syscall(SYS_gettid);
+ EXPECT_NE(tgid, tid);
+ const auto thread_name = ASSERT_NO_ERRNO_AND_VALUE(ThreadName());
+
+ std::string status_str = ASSERT_NO_ERRNO_AND_VALUE(
+ GetContents(absl::StrCat("/proc/", tid, "/status")));
+
+ ASSERT_FALSE(status_str.empty());
+ const auto status = ASSERT_NO_ERRNO_AND_VALUE(ParseProcStatus(status_str));
+ EXPECT_THAT(status, IsSupersetOf({Pair("Name", thread_name),
+ Pair("Tgid", absl::StrCat(tgid)),
+ Pair("Pid", absl::StrCat(tid)),
+ Pair("PPid", absl::StrCat(getppid()))}));
+ });
+}
+
+TEST(ProcPidStatusTest, StateRunning) {
+ // Task must be running when reading the file.
+ const pid_t tid = syscall(SYS_gettid);
+ std::string status_str = ASSERT_NO_ERRNO_AND_VALUE(
+ GetContents(absl::StrCat("/proc/", tid, "/status")));
+
+ EXPECT_THAT(ParseProcStatus(status_str),
+ IsPosixErrorOkAndHolds(Contains(Pair("State", "R (running)"))));
+}
+
+TEST(ProcPidStatusTest, StateSleeping_NoRandomSave) {
+ // Starts a child process that blocks and checks that State is sleeping.
+ auto res = WithSubprocess(
+ [&](int pid) -> PosixError {
+ // Because this test is timing based we will disable cooperative saving
+ // and the test itself also has random saving disabled.
+ const DisableSave ds;
+ // Try multiple times in case the child isn't sleeping when status file
+ // is read.
+ MonotonicTimer timer;
+ timer.Start();
+ for (;;) {
+ ASSIGN_OR_RETURN_ERRNO(
+ std::string status_str,
+ GetContents(absl::StrCat("/proc/", pid, "/status")));
+ ASSIGN_OR_RETURN_ERRNO(auto map, ParseProcStatus(status_str));
+ if (map["State"] == std::string("S (sleeping)")) {
+ // Test passed!
+ return NoError();
+ }
+ if (timer.Duration() > absl::Seconds(10)) {
+ return PosixError(ETIMEDOUT, "Timeout waiting for child to sleep");
+ }
+ absl::SleepFor(absl::Milliseconds(10));
+ }
+ },
+ nullptr, nullptr);
+ ASSERT_NO_ERRNO(res);
+}
+
+TEST(ProcPidStatusTest, ValuesAreTabDelimited) {
+ std::string status_str =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/status"));
+ ASSERT_FALSE(status_str.empty());
+ for (absl::string_view const line :
+ absl::StrSplit(status_str, '\n', absl::SkipWhitespace())) {
+ EXPECT_NE(std::string::npos, line.find(":\t"));
+ }
+}
+
+// Threads properly counts running threads.
+//
+// TODO: Test zombied threads while the thread group leader is still
+// running with generalized fork and clone children from the wait test.
+TEST(ProcPidStatusTest, Threads) {
+ char buf[4096] = {};
+ EXPECT_THAT(ReadWhileRunning("status", buf, sizeof(buf) - 1),
+ SyscallSucceedsWithValue(Gt(0)));
+
+ auto status = ASSERT_NO_ERRNO_AND_VALUE(ParseProcStatus(buf));
+ auto it = status.find("Threads");
+ ASSERT_NE(it, status.end());
+ int threads = -1;
+ EXPECT_TRUE(absl::SimpleAtoi(it->second, &threads))
+ << "Threads value " << it->second << " is not a number";
+ // Don't make assumptions about the exact number of threads, as it may not be
+ // constant.
+ EXPECT_GE(threads, 1);
+
+ memset(buf, 0, sizeof(buf));
+ EXPECT_THAT(ReadWhileZombied("status", buf, sizeof(buf) - 1),
+ SyscallSucceedsWithValue(Gt(0)));
+
+ status = ASSERT_NO_ERRNO_AND_VALUE(ParseProcStatus(buf));
+ it = status.find("Threads");
+ ASSERT_NE(it, status.end());
+ threads = -1;
+ EXPECT_TRUE(absl::SimpleAtoi(it->second, &threads))
+ << "Threads value " << it->second << " is not a number";
+ // There must be only the thread group leader remaining, zombied.
+ EXPECT_EQ(threads, 1);
+}
+
+// Returns true if all characters in s are digits.
+bool IsDigits(absl::string_view s) {
+ return std::all_of(s.begin(), s.end(), absl::ascii_isdigit);
+}
+
+TEST(ProcPidStatTest, VSSRSS) {
+ std::string status_str =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/status"));
+ ASSERT_FALSE(status_str.empty());
+ auto status = ASSERT_NO_ERRNO_AND_VALUE(ParseProcStatus(status_str));
+
+ const auto vss_it = status.find("VmSize");
+ ASSERT_NE(vss_it, status.end());
+
+ absl::string_view vss_str(vss_it->second);
+
+ // Room for the " kB" suffix plus at least one digit.
+ ASSERT_GT(vss_str.length(), 3);
+ EXPECT_TRUE(absl::EndsWith(vss_str, " kB"));
+ // Everything else is part of a number.
+ EXPECT_TRUE(IsDigits(vss_str.substr(0, vss_str.length() - 3))) << vss_str;
+ // ... which is not 0.
+ EXPECT_NE('0', vss_str[0]);
+
+ const auto rss_it = status.find("VmRSS");
+ ASSERT_NE(rss_it, status.end());
+
+ absl::string_view rss_str(rss_it->second);
+
+ // Room for the " kB" suffix plus at least one digit.
+ ASSERT_GT(rss_str.length(), 3);
+ EXPECT_TRUE(absl::EndsWith(rss_str, " kB"));
+ // Everything else is part of a number.
+ EXPECT_TRUE(IsDigits(rss_str.substr(0, rss_str.length() - 3))) << rss_str;
+ // ... which is not 0.
+ EXPECT_NE('0', rss_str[0]);
+}
+
+// Parse an array of NUL-terminated char* arrays, returning a vector of strings.
+std::vector<std::string> ParseNulTerminatedStrings(std::string contents) {
+ EXPECT_EQ('\0', contents.back());
+ // The split will leave an empty std::string if the NUL-byte remains, so pop it.
+ contents.pop_back();
+
+ return absl::StrSplit(contents, '\0');
+}
+
+TEST(ProcPidCmdline, MatchesArgv) {
+ std::vector<std::string> proc_cmdline = ParseNulTerminatedStrings(
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/cmdline")));
+ EXPECT_THAT(saved_argv, ContainerEq(proc_cmdline));
+}
+
+TEST(ProcPidEnviron, MatchesEnviron) {
+ std::vector<std::string> proc_environ = ParseNulTerminatedStrings(
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/environ")));
+ // Get the environment from the environ variable, which we will compare with
+ // /proc/self/environ.
+ std::vector<std::string> env;
+ for (char** v = environ; *v; v++) {
+ env.push_back(*v);
+ }
+ EXPECT_THAT(env, ContainerEq(proc_environ));
+}
+
+TEST(ProcPidCmdline, SubprocessForkSameCmdline) {
+ std::vector<std::string> proc_cmdline_parent;
+ std::vector<std::string> proc_cmdline;
+ proc_cmdline_parent = ParseNulTerminatedStrings(
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/cmdline")));
+ auto res = WithSubprocess(
+ [&](int pid) -> PosixError {
+ ASSIGN_OR_RETURN_ERRNO(
+ auto raw_cmdline,
+ GetContents(absl::StrCat("/proc/", pid, "/cmdline")));
+ proc_cmdline = ParseNulTerminatedStrings(raw_cmdline);
+ return NoError();
+ },
+ nullptr, nullptr);
+ ASSERT_NO_ERRNO(res);
+
+ for (size_t i = 0; i < proc_cmdline_parent.size(); i++) {
+ EXPECT_EQ(proc_cmdline_parent[i], proc_cmdline[i]);
+ }
+}
+
+// Test whether /proc/PID/ symlinks can be read for a running process.
+TEST(ProcPidSymlink, SubprocessRunning) {
+ char buf[1];
+
+ EXPECT_THAT(ReadlinkWhileRunning("exe", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadlinkWhileRunning("ns/net", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadlinkWhileRunning("ns/pid", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadlinkWhileRunning("ns/user", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+}
+// FIXME: Inconsistent behavior between gVisor and linux
+// on proc files.
+TEST(ProcPidSymlink, SubprocessZombied) {
+ ASSERT_NO_ERRNO(SetCapability(CAP_DAC_OVERRIDE, false));
+ ASSERT_NO_ERRNO(SetCapability(CAP_DAC_READ_SEARCH, false));
+
+ char buf[1];
+
+ int want = EACCES;
+ if (!IsRunningOnGvisor()) {
+ auto version = ASSERT_NO_ERRNO_AND_VALUE(GetKernelVersion());
+ if (version.major == 4 && version.minor > 3) {
+ want = ENOENT;
+ }
+ }
+
+ EXPECT_THAT(ReadlinkWhileZombied("exe", buf, sizeof(buf)),
+ SyscallFailsWithErrno(want));
+
+ if (!IsRunningOnGvisor()) {
+ EXPECT_THAT(ReadlinkWhileZombied("ns/net", buf, sizeof(buf)),
+ SyscallFailsWithErrno(want));
+ }
+
+ // FIXME: Inconsistent behavior between gVisor and linux
+ // on proc files.
+ // 4.17 & gVisor: Syscall succeeds and returns 1
+ // EXPECT_THAT(ReadlinkWhileZombied("ns/pid", buf, sizeof(buf)),
+ // SyscallFailsWithErrno(EACCES));
+
+ // FIXME: Inconsistent behavior between gVisor and linux
+ // on proc files.
+ // 4.17 & gVisor: Syscall succeeds and returns 1.
+ // EXPECT_THAT(ReadlinkWhileZombied("ns/user", buf, sizeof(buf)),
+ // SyscallFailsWithErrno(EACCES));
+}
+
+// Test whether /proc/PID/ symlinks can be read for an exited process.
+TEST(ProcPidSymlink, SubprocessExited) {
+ // FIXME: These all succeed on gVisor.
+ SKIP_IF(IsRunningOnGvisor());
+
+ char buf[1];
+
+ EXPECT_THAT(ReadlinkWhileExited("exe", buf, sizeof(buf)),
+ SyscallFailsWithErrno(ESRCH));
+
+ EXPECT_THAT(ReadlinkWhileExited("ns/net", buf, sizeof(buf)),
+ SyscallFailsWithErrno(ESRCH));
+
+ EXPECT_THAT(ReadlinkWhileExited("ns/pid", buf, sizeof(buf)),
+ SyscallFailsWithErrno(ESRCH));
+
+ EXPECT_THAT(ReadlinkWhileExited("ns/user", buf, sizeof(buf)),
+ SyscallFailsWithErrno(ESRCH));
+}
+
+// /proc/PID/exe points to the correct binary.
+TEST(ProcPidExe, Subprocess) {
+ auto link = ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/self/exe"));
+ auto expected_absolute_path =
+ ASSERT_NO_ERRNO_AND_VALUE(MakeAbsolute(link, ""));
+
+ char actual[PATH_MAX + 1] = {};
+ ASSERT_THAT(ReadlinkWhileRunning("exe", actual, sizeof(actual)),
+ SyscallSucceedsWithValue(Gt(0)));
+ EXPECT_EQ(actual, expected_absolute_path);
+}
+
+// Test whether /proc/PID/ files can be read for a running process.
+TEST(ProcPidFile, SubprocessRunning) {
+ char buf[1];
+
+ EXPECT_THAT(ReadWhileRunning("auxv", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileRunning("cmdline", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileRunning("comm", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileRunning("gid_map", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileRunning("io", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileRunning("maps", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileRunning("stat", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileRunning("status", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileRunning("uid_map", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+}
+
+// Test whether /proc/PID/ files can be read for a zombie process.
+TEST(ProcPidFile, SubprocessZombie) {
+ char buf[1];
+ // 4.17: Succeeds and returns 1
+ // gVisor: Succeds and returns 0
+ EXPECT_THAT(ReadWhileZombied("auxv", buf, sizeof(buf)), SyscallSucceeds());
+
+ EXPECT_THAT(ReadWhileZombied("cmdline", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(0));
+
+ EXPECT_THAT(ReadWhileZombied("comm", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileZombied("gid_map", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileZombied("maps", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(0));
+
+ EXPECT_THAT(ReadWhileZombied("stat", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileZombied("status", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ EXPECT_THAT(ReadWhileZombied("uid_map", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ // FIXME: Inconsistent behavior between gVisor and linux
+ // on proc files.
+ // gVisor & 4.17: Succeeds and returns 1.
+ // EXPECT_THAT(ReadWhileZombied("io", buf, sizeof(buf)),
+ // SyscallFailsWithErrno(EACCES));
+}
+
+// Test whether /proc/PID/ files can be read for an exited process.
+TEST(ProcPidFile, SubprocessExited) {
+ char buf[1];
+
+ // FIXME: Inconsistent behavior between kernels
+ // gVisor: Fails with ESRCH.
+ // 4.17: Succeeds and returns 1.
+ // EXPECT_THAT(ReadWhileExited("auxv", buf, sizeof(buf)),
+ // SyscallFailsWithErrno(ESRCH));
+
+ EXPECT_THAT(ReadWhileExited("cmdline", buf, sizeof(buf)),
+ SyscallFailsWithErrno(ESRCH));
+
+ if (!IsRunningOnGvisor()) {
+ // FIXME: Succeeds on gVisor.
+ EXPECT_THAT(ReadWhileExited("comm", buf, sizeof(buf)),
+ SyscallFailsWithErrno(ESRCH));
+ }
+
+ EXPECT_THAT(ReadWhileExited("gid_map", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+
+ if (!IsRunningOnGvisor()) {
+ // FIXME: Succeeds on gVisor.
+ EXPECT_THAT(ReadWhileExited("io", buf, sizeof(buf)),
+ SyscallFailsWithErrno(ESRCH));
+ }
+
+ if (!IsRunningOnGvisor()) {
+ // FIXME: Returns EOF on gVisor.
+ EXPECT_THAT(ReadWhileExited("maps", buf, sizeof(buf)),
+ SyscallFailsWithErrno(ESRCH));
+ }
+
+ if (!IsRunningOnGvisor()) {
+ // FIXME: Succeeds on gVisor.
+ EXPECT_THAT(ReadWhileExited("stat", buf, sizeof(buf)),
+ SyscallFailsWithErrno(ESRCH));
+ }
+
+ if (!IsRunningOnGvisor()) {
+ // FIXME: Succeeds on gVisor.
+ EXPECT_THAT(ReadWhileExited("status", buf, sizeof(buf)),
+ SyscallFailsWithErrno(ESRCH));
+ }
+
+ EXPECT_THAT(ReadWhileExited("uid_map", buf, sizeof(buf)),
+ SyscallSucceedsWithValue(sizeof(buf)));
+}
+
+PosixError DirContainsImpl(absl::string_view path,
+ const std::vector<std::string>& targets, bool strict) {
+ ASSIGN_OR_RETURN_ERRNO(auto listing, ListDir(path, false));
+ bool success = true;
+
+ for (auto& expected_entry : targets) {
+ auto cursor = std::find(listing.begin(), listing.end(), expected_entry);
+ if (cursor == listing.end()) {
+ success = false;
+ }
+ }
+
+ if (!success) {
+ return PosixError(
+ ENOENT,
+ absl::StrCat("Failed to find one or more paths in '", path, "'"));
+ }
+
+ if (strict) {
+ if (targets.size() != listing.size()) {
+ return PosixError(
+ EINVAL,
+ absl::StrCat("Expected to find ", targets.size(), " elements in '",
+ path, "', but found ", listing.size()));
+ }
+ }
+
+ return NoError();
+}
+
+PosixError DirContains(absl::string_view path,
+ const std::vector<std::string>& targets) {
+ return DirContainsImpl(path, targets, false);
+}
+
+PosixError DirContainsExactly(absl::string_view path,
+ const std::vector<std::string>& targets) {
+ return DirContainsImpl(path, targets, true);
+}
+
+PosixError EventuallyDirContainsExactly(absl::string_view path,
+ const std::vector<std::string>& targets) {
+ constexpr int kRetryCount = 100;
+ const absl::Duration kRetryDelay = absl::Milliseconds(100);
+
+ for (int i = 0; i < kRetryCount; ++i) {
+ auto res = DirContainsExactly(path, targets);
+ if (res.ok()) {
+ return res;
+ } else if (i < kRetryCount - 1) {
+ // Sleep if this isn't the final iteration.
+ absl::SleepFor(kRetryDelay);
+ }
+ }
+ return PosixError(ETIMEDOUT,
+ "Timed out while waiting for directory to contain files ");
+}
+
+TEST(ProcTask, Basic) {
+ EXPECT_NO_ERRNO(
+ DirContains("/proc/self/task", {".", "..", absl::StrCat(getpid())}));
+}
+
+std::vector<std::string> TaskFiles(const std::vector<std::string>& initial_contents,
+ const std::vector<pid_t>& pids) {
+ return VecCat<std::string>(
+ initial_contents,
+ ApplyVec<std::string>([](const pid_t p) { return absl::StrCat(p); }, pids));
+}
+
+std::vector<std::string> TaskFiles(const std::vector<pid_t>& pids) {
+ return TaskFiles({".", "..", absl::StrCat(getpid())}, pids);
+}
+
+// Helper class for creating a new task in the current thread group.
+class BlockingChild {
+ public:
+ BlockingChild() : thread_([=] { Start(); }) {}
+ ~BlockingChild() { Join(); }
+
+ pid_t Tid() const {
+ absl::MutexLock ml(&mu_);
+ mu_.Await(absl::Condition(&tid_ready_));
+ return tid_;
+ }
+
+ void Join() { Stop(); }
+
+ private:
+ void Start() {
+ absl::MutexLock ml(&mu_);
+ tid_ = syscall(__NR_gettid);
+ tid_ready_ = true;
+ mu_.Await(absl::Condition(&stop_));
+ }
+
+ void Stop() {
+ absl::MutexLock ml(&mu_);
+ stop_ = true;
+ }
+
+ mutable absl::Mutex mu_;
+ bool stop_ GUARDED_BY(mu_) = false;
+ pid_t tid_;
+ bool tid_ready_ GUARDED_BY(mu_) = false;
+
+ // Must be last to ensure that the destructor for the thread is run before
+ // any other member of the object is destroyed.
+ ScopedThread thread_;
+};
+
+TEST(ProcTask, NewThreadAppears) {
+ auto initial = ASSERT_NO_ERRNO_AND_VALUE(ListDir("/proc/self/task", false));
+ BlockingChild child1;
+ EXPECT_NO_ERRNO(DirContainsExactly("/proc/self/task",
+ TaskFiles(initial, {child1.Tid()})));
+}
+
+TEST(ProcTask, KilledThreadsDisappear) {
+ auto initial = ASSERT_NO_ERRNO_AND_VALUE(ListDir("/proc/self/task/", false));
+
+ BlockingChild child1;
+ EXPECT_NO_ERRNO(DirContainsExactly("/proc/self/task",
+ TaskFiles(initial, {child1.Tid()})));
+
+ // Stat child1's task file.
+ struct stat statbuf;
+ const std::string child1_task_file =
+ absl::StrCat("/proc/self/task/", child1.Tid());
+ EXPECT_THAT(stat(child1_task_file.c_str(), &statbuf), SyscallSucceeds());
+
+ BlockingChild child2;
+ EXPECT_NO_ERRNO(DirContainsExactly(
+ "/proc/self/task", TaskFiles(initial, {child1.Tid(), child2.Tid()})));
+
+ BlockingChild child3;
+ BlockingChild child4;
+ BlockingChild child5;
+ EXPECT_NO_ERRNO(DirContainsExactly(
+ "/proc/self/task",
+ TaskFiles(initial, {child1.Tid(), child2.Tid(), child3.Tid(),
+ child4.Tid(), child5.Tid()})));
+
+ child2.Join();
+ EXPECT_NO_ERRNO(EventuallyDirContainsExactly(
+ "/proc/self/task", TaskFiles(initial, {child1.Tid(), child3.Tid(),
+ child4.Tid(), child5.Tid()})));
+
+ child1.Join();
+ child4.Join();
+ EXPECT_NO_ERRNO(EventuallyDirContainsExactly(
+ "/proc/self/task", TaskFiles(initial, {child3.Tid(), child5.Tid()})));
+
+ // Stat child1's task file again. This time it should fail.
+ EXPECT_THAT(stat(child1_task_file.c_str(), &statbuf),
+ SyscallFailsWithErrno(ENOENT));
+
+ child3.Join();
+ child5.Join();
+ EXPECT_NO_ERRNO(EventuallyDirContainsExactly("/proc/self/task", initial));
+}
+
+TEST(ProcTask, ChildTaskDir) {
+ BlockingChild child1;
+ EXPECT_NO_ERRNO(DirContains("/proc/self/task", TaskFiles({child1.Tid()})));
+ EXPECT_NO_ERRNO(DirContains(absl::StrCat("/proc/", child1.Tid(), "/task"),
+ TaskFiles({child1.Tid()})));
+}
+
+PosixError VerifyPidDir(std::string path) {
+ return DirContains(path, {"exe", "fd", "io", "maps", "ns", "stat", "status"});
+}
+
+TEST(ProcTask, VerifyTaskDir) {
+ EXPECT_NO_ERRNO(VerifyPidDir("/proc/self"));
+
+ EXPECT_NO_ERRNO(VerifyPidDir(absl::StrCat("/proc/self/task/", getpid())));
+ BlockingChild child1;
+ EXPECT_NO_ERRNO(VerifyPidDir(absl::StrCat("/proc/self/task/", child1.Tid())));
+
+ // Only the first level of task directories should contain the 'task'
+ // directory. That is:
+ //
+ // /proc/1234/task <- should exist
+ // /proc/1234/task/1234/task <- should not exist
+ // /proc/1234/task/1235/task <- should not exist (where 1235 is in the same
+ // thread group as 1234).
+ EXPECT_FALSE(
+ DirContains(absl::StrCat("/proc/self/task/", getpid()), {"task"}).ok())
+ << "Found 'task' directory in an inner directory.";
+}
+
+TEST(ProcTask, TaskDirCannotBeDeleted) {
+ // Drop capabilities that allow us to override file and directory permissions.
+ ASSERT_NO_ERRNO(SetCapability(CAP_DAC_OVERRIDE, false));
+
+ EXPECT_THAT(rmdir("/proc/self/task"), SyscallFails());
+ EXPECT_THAT(rmdir(absl::StrCat("/proc/self/task/", getpid()).c_str()),
+ SyscallFailsWithErrno(EACCES));
+}
+
+TEST(ProcTask, TaskDirHasCorrectMetadata) {
+ struct stat st;
+ EXPECT_THAT(stat("/proc/self/task", &st), SyscallSucceeds());
+ EXPECT_TRUE(S_ISDIR(st.st_mode));
+
+ // Verify file is readable and executable by everyone.
+ mode_t expected_permissions =
+ S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
+ mode_t permissions = st.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO);
+ EXPECT_EQ(expected_permissions, permissions);
+}
+
+TEST(ProcTask, TaskDirCanSeekToEnd) {
+ const FileDescriptor dirfd =
+ ASSERT_NO_ERRNO_AND_VALUE(Open("/proc/self/task", O_RDONLY));
+ EXPECT_THAT(lseek(dirfd.get(), 0, SEEK_END), SyscallSucceeds());
+}
+
+TEST(ProcTask, VerifyTaskDirNlinks) {
+ // A task directory will have 3 links if the taskgroup has a single
+ // thread. For example, the following shows where the links to
+ // '/proc/12345/task comes' from for a single threaded process with pid 12345:
+ //
+ // /proc/12345/task <-- 1 link for the directory itself
+ // . <-- link from "."
+ // ..
+ // 12345
+ // .
+ // .. <-- link from ".." to parent.
+ // <other contents of a task dir>
+ //
+ // We can't assert an absolute number of links since we don't control how many
+ // threads the test framework spawns. Instead, we'll ensure creating a new
+ // thread increases the number of links as expected.
+
+ // Once we reach the test body, we can count on the thread count being stable
+ // unless we spawn a new one.
+ uint64_t initial_links = ASSERT_NO_ERRNO_AND_VALUE(Links("/proc/self/task"));
+ ASSERT_GE(initial_links, 3);
+
+ // For each new subtask, we should gain a new link.
+ BlockingChild child1;
+ EXPECT_THAT(Links("/proc/self/task"),
+ IsPosixErrorOkAndHolds(initial_links + 1));
+ BlockingChild child2;
+ EXPECT_THAT(Links("/proc/self/task"),
+ IsPosixErrorOkAndHolds(initial_links + 2));
+}
+
+TEST(ProcTask, CommContainsThreadNameAndTrailingNewline) {
+ constexpr char kThreadName[] = "TestThread12345";
+ ASSERT_THAT(prctl(PR_SET_NAME, kThreadName), SyscallSucceeds());
+
+ auto thread_name = ASSERT_NO_ERRNO_AND_VALUE(
+ GetContents(JoinPath("/proc", absl::StrCat(getpid()), "task",
+ absl::StrCat(syscall(SYS_gettid)), "comm")));
+ EXPECT_EQ(absl::StrCat(kThreadName, "\n"), thread_name);
+}
+
+TEST(ProcTaskNs, NsDirExistsAndHasCorrectMetadata) {
+ EXPECT_NO_ERRNO(DirContains("/proc/self/ns", {"net", "pid", "user"}));
+
+ // Let's just test the 'pid' entry, all of them are very similar.
+ struct stat st;
+ EXPECT_THAT(lstat("/proc/self/ns/pid", &st), SyscallSucceeds());
+ EXPECT_TRUE(S_ISLNK(st.st_mode));
+
+ auto link = ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/self/ns/pid"));
+ EXPECT_THAT(link, ::testing::StartsWith("pid:["));
+}
+
+TEST(ProcTaskNs, AccessOnNsNodeSucceeds) {
+ EXPECT_THAT(access("/proc/self/ns/pid", F_OK), SyscallSucceeds());
+}
+
+TEST(ProcSysKernelHostname, Exists) {
+ EXPECT_THAT(open("/proc/sys/kernel/hostname", O_RDONLY), SyscallSucceeds());
+}
+
+TEST(ProcSysKernelHostname, MatchesUname) {
+ struct utsname buf;
+ EXPECT_THAT(uname(&buf), SyscallSucceeds());
+ const std::string hostname = absl::StrCat(buf.nodename, "\n");
+ auto procfs_hostname =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/sys/kernel/hostname"));
+ EXPECT_EQ(procfs_hostname, hostname);
+}
+
+TEST(ProcSysVmMmapMinAddr, HasNumericValue) {
+ const std::string mmap_min_addr_str =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/sys/vm/mmap_min_addr"));
+ uintptr_t mmap_min_addr;
+ EXPECT_TRUE(absl::SimpleAtoi(mmap_min_addr_str, &mmap_min_addr))
+ << "/proc/sys/vm/mmap_min_addr does not contain a numeric value: "
+ << mmap_min_addr_str;
+}
+
+TEST(ProcSysVmOvercommitMemory, HasNumericValue) {
+ const std::string overcommit_memory_str =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/sys/vm/overcommit_memory"));
+ uintptr_t overcommit_memory;
+ EXPECT_TRUE(absl::SimpleAtoi(overcommit_memory_str, &overcommit_memory))
+ << "/proc/sys/vm/overcommit_memory does not contain a numeric value: "
+ << overcommit_memory;
+}
+
+// Check that link for proc fd entries point the target node, not the
+// symlink itself.
+TEST(ProcTaskFd, FstatatFollowsSymlink) {
+ const TempPath file = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateFile());
+ const FileDescriptor fd =
+ ASSERT_NO_ERRNO_AND_VALUE(Open(file.path(), O_RDONLY));
+
+ struct stat sproc = {};
+ EXPECT_THAT(
+ fstatat(-1, absl::StrCat("/proc/self/fd/", fd.get()).c_str(), &sproc, 0),
+ SyscallSucceeds());
+
+ struct stat sfile = {};
+ EXPECT_THAT(fstatat(-1, file.path().c_str(), &sfile, 0), SyscallSucceeds());
+
+ // If fstatat follows the fd symlink, the device and inode numbers should
+ // match at a minimum.
+ EXPECT_EQ(sproc.st_dev, sfile.st_dev);
+ EXPECT_EQ(sproc.st_ino, sfile.st_ino);
+ EXPECT_EQ(0, memcmp(&sfile, &sproc, sizeof(sfile)));
+}
+
+TEST(ProcFilesystems, Bug65172365) {
+ std::string proc_filesystems =
+ ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/filesystems"));
+ ASSERT_FALSE(proc_filesystems.empty());
+}
+
+TEST(ProcFilesystems, PresenceOfShmMaxMniAll) {
+ uint64_t shmmax = 0;
+ uint64_t shmall = 0;
+ uint64_t shmmni = 0;
+ std::string proc_file;
+ proc_file = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/sys/kernel/shmmax"));
+ ASSERT_FALSE(proc_file.empty());
+ ASSERT_TRUE(absl::SimpleAtoi(proc_file, &shmmax));
+ proc_file = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/sys/kernel/shmall"));
+ ASSERT_FALSE(proc_file.empty());
+ ASSERT_TRUE(absl::SimpleAtoi(proc_file, &shmall));
+ proc_file = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/sys/kernel/shmmni"));
+ ASSERT_FALSE(proc_file.empty());
+ ASSERT_TRUE(absl::SimpleAtoi(proc_file, &shmmni));
+
+ ASSERT_GT(shmmax, 0);
+ ASSERT_GT(shmall, 0);
+ ASSERT_GT(shmmni, 0);
+ ASSERT_LE(shmall, shmmax);
+
+ // These values should never be higher than this by default, for more
+ // information see uapi/linux/shm.h
+ ASSERT_LE(shmmax, ULONG_MAX - (1UL << 24));
+ ASSERT_LE(shmall, ULONG_MAX - (1UL << 24));
+}
+
+// Check that /proc/mounts is a symlink to self/mounts.
+TEST(ProcMounts, IsSymlink) {
+ auto link = ASSERT_NO_ERRNO_AND_VALUE(ReadLink("/proc/mounts"));
+ EXPECT_EQ(link, "self/mounts");
+}
+
+// Check that /proc/self/mounts looks something like a real mounts file.
+TEST(ProcSelfMounts, RequiredFieldsArePresent) {
+ auto mounts = ASSERT_NO_ERRNO_AND_VALUE(GetContents("/proc/self/mounts"));
+ EXPECT_THAT(mounts,
+ AllOf(
+ // Root mount.
+ ContainsRegex(R"(\S+ / \S+ (rw|ro)\S* [0-9]+ [0-9]+\s)"),
+ // Root mount.
+ ContainsRegex(R"(\S+ /proc \S+ rw\S* [0-9]+ [0-9]+\s)")));
+}
+} // namespace
+} // namespace testing
+} // namespace gvisor
+
+int main(int argc, char** argv) {
+ for (int i = 0; i < argc; ++i) {
+ gvisor::testing::saved_argv.emplace_back(std::string(argv[i]));
+ }
+
+ gvisor::testing::TestInit(&argc, &argv);
+ return RUN_ALL_TESTS();
+}