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      1 //
      2 // Copyright (C) 2012 The Android Open Source Project
      3 //
      4 // Licensed under the Apache License, Version 2.0 (the "License");
      5 // you may not use this file except in compliance with the License.
      6 // You may obtain a copy of the License at
      7 //
      8 //      http://www.apache.org/licenses/LICENSE-2.0
      9 //
     10 // Unless required by applicable law or agreed to in writing, software
     11 // distributed under the License is distributed on an "AS IS" BASIS,
     12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13 // See the License for the specific language governing permissions and
     14 // limitations under the License.
     15 //
     16 
     17 #include "update_engine/common/subprocess.h"
     18 
     19 #include <fcntl.h>
     20 #include <poll.h>
     21 #include <sys/types.h>
     22 #include <unistd.h>
     23 
     24 #include <set>
     25 #include <string>
     26 #include <vector>
     27 
     28 #include <base/bind.h>
     29 #include <base/files/scoped_temp_dir.h>
     30 #include <base/location.h>
     31 #include <base/message_loop/message_loop.h>
     32 #include <base/strings/string_util.h>
     33 #include <base/strings/stringprintf.h>
     34 #include <base/time/time.h>
     35 #include <brillo/message_loops/base_message_loop.h>
     36 #include <brillo/message_loops/message_loop.h>
     37 #include <brillo/message_loops/message_loop_utils.h>
     38 #include <brillo/strings/string_utils.h>
     39 #include <brillo/unittest_utils.h>
     40 #include <gtest/gtest.h>
     41 
     42 #include "update_engine/common/test_utils.h"
     43 #include "update_engine/common/utils.h"
     44 
     45 using base::TimeDelta;
     46 using brillo::MessageLoop;
     47 using std::string;
     48 using std::vector;
     49 
     50 namespace {
     51 
     52 #ifdef __ANDROID__
     53 #define kBinPath "/system/bin"
     54 #define kUsrBinPath "/system/bin"
     55 #else
     56 #define kBinPath "/bin"
     57 #define kUsrBinPath "/usr/bin"
     58 #endif  // __ANDROID__
     59 
     60 }  // namespace
     61 
     62 namespace chromeos_update_engine {
     63 
     64 class SubprocessTest : public ::testing::Test {
     65  protected:
     66   void SetUp() override {
     67     loop_.SetAsCurrent();
     68     async_signal_handler_.Init();
     69     subprocess_.Init(&async_signal_handler_);
     70   }
     71 
     72   base::MessageLoopForIO base_loop_;
     73   brillo::BaseMessageLoop loop_{&base_loop_};
     74   brillo::AsynchronousSignalHandler async_signal_handler_;
     75   Subprocess subprocess_;
     76 };
     77 
     78 namespace {
     79 
     80 void ExpectedResults(int expected_return_code, const string& expected_output,
     81                      int return_code, const string& output) {
     82   EXPECT_EQ(expected_return_code, return_code);
     83   EXPECT_EQ(expected_output, output);
     84   MessageLoop::current()->BreakLoop();
     85 }
     86 
     87 void ExpectedEnvVars(int return_code, const string& output) {
     88   EXPECT_EQ(0, return_code);
     89   const std::set<string> allowed_envs = {"LD_LIBRARY_PATH", "PATH"};
     90   for (const string& key_value : brillo::string_utils::Split(output, "\n")) {
     91     auto key_value_pair = brillo::string_utils::SplitAtFirst(
     92         key_value, "=", true);
     93     EXPECT_NE(allowed_envs.end(), allowed_envs.find(key_value_pair.first));
     94   }
     95   MessageLoop::current()->BreakLoop();
     96 }
     97 
     98 void ExpectedDataOnPipe(const Subprocess* subprocess,
     99                         pid_t* pid,
    100                         int child_fd,
    101                         const string& child_fd_data,
    102                         int expected_return_code,
    103                         int return_code,
    104                         const string& /* output */) {
    105   EXPECT_EQ(expected_return_code, return_code);
    106 
    107   // Verify that we can read the data from our end of |child_fd|.
    108   int fd = subprocess->GetPipeFd(*pid, child_fd);
    109   EXPECT_NE(-1, fd);
    110   vector<char> buf(child_fd_data.size() + 1);
    111   EXPECT_EQ(static_cast<ssize_t>(child_fd_data.size()),
    112             HANDLE_EINTR(read(fd, buf.data(), buf.size())));
    113   EXPECT_EQ(child_fd_data,
    114             string(buf.begin(), buf.begin() + child_fd_data.size()));
    115 
    116   MessageLoop::current()->BreakLoop();
    117 }
    118 
    119 }  // namespace
    120 
    121 TEST_F(SubprocessTest, IsASingleton) {
    122   EXPECT_EQ(&subprocess_, &Subprocess::Get());
    123 }
    124 
    125 TEST_F(SubprocessTest, InactiveInstancesDontChangeTheSingleton) {
    126   std::unique_ptr<Subprocess> another_subprocess(new Subprocess());
    127   EXPECT_EQ(&subprocess_, &Subprocess::Get());
    128   another_subprocess.reset();
    129   EXPECT_EQ(&subprocess_, &Subprocess::Get());
    130 }
    131 
    132 TEST_F(SubprocessTest, SimpleTest) {
    133   EXPECT_TRUE(subprocess_.Exec({kBinPath "/false"},
    134                                base::Bind(&ExpectedResults, 1, "")));
    135   loop_.Run();
    136 }
    137 
    138 TEST_F(SubprocessTest, EchoTest) {
    139   EXPECT_TRUE(subprocess_.Exec(
    140       {kBinPath "/sh", "-c", "echo this is stdout; echo this is stderr >&2"},
    141       base::Bind(&ExpectedResults, 0, "this is stdout\nthis is stderr\n")));
    142   loop_.Run();
    143 }
    144 
    145 TEST_F(SubprocessTest, StderrNotIncludedInOutputTest) {
    146   EXPECT_TRUE(subprocess_.ExecFlags(
    147       {kBinPath "/sh", "-c", "echo on stdout; echo on stderr >&2"},
    148       0,
    149       {},
    150       base::Bind(&ExpectedResults, 0, "on stdout\n")));
    151   loop_.Run();
    152 }
    153 
    154 TEST_F(SubprocessTest, PipeRedirectFdTest) {
    155   pid_t pid;
    156   pid = subprocess_.ExecFlags(
    157       {kBinPath "/sh", "-c", "echo on pipe >&3"},
    158       0,
    159       {3},
    160       base::Bind(&ExpectedDataOnPipe, &subprocess_, &pid, 3, "on pipe\n", 0));
    161   EXPECT_NE(0, pid);
    162 
    163   // Wrong file descriptor values should return -1.
    164   EXPECT_EQ(-1, subprocess_.GetPipeFd(pid, 123));
    165   loop_.Run();
    166   // Calling GetPipeFd() after the callback runs is invalid.
    167   EXPECT_EQ(-1, subprocess_.GetPipeFd(pid, 3));
    168 }
    169 
    170 // Test that a pipe file descriptor open in the parent is not open in the child.
    171 TEST_F(SubprocessTest, PipeClosedWhenNotRedirectedTest) {
    172   brillo::ScopedPipe pipe;
    173 
    174   // test_subprocess will return with the errno of fstat, which should be EBADF
    175   // if the passed file descriptor is closed in the child.
    176   const vector<string> cmd = {
    177       test_utils::GetBuildArtifactsPath("test_subprocess"),
    178       "fstat",
    179       std::to_string(pipe.writer)};
    180   EXPECT_TRUE(subprocess_.ExecFlags(
    181       cmd, 0, {}, base::Bind(&ExpectedResults, EBADF, "")));
    182   loop_.Run();
    183 }
    184 
    185 TEST_F(SubprocessTest, EnvVarsAreFiltered) {
    186   EXPECT_TRUE(
    187       subprocess_.Exec({kUsrBinPath "/env"}, base::Bind(&ExpectedEnvVars)));
    188   loop_.Run();
    189 }
    190 
    191 TEST_F(SubprocessTest, SynchronousTrueSearchsOnPath) {
    192   int rc = -1;
    193   EXPECT_TRUE(Subprocess::SynchronousExecFlags(
    194       {"true"}, Subprocess::kSearchPath, &rc, nullptr));
    195   EXPECT_EQ(0, rc);
    196 }
    197 
    198 TEST_F(SubprocessTest, SynchronousEchoTest) {
    199   vector<string> cmd = {
    200       kBinPath "/sh",
    201       "-c",
    202       "echo -n stdout-here; echo -n stderr-there >&2"};
    203   int rc = -1;
    204   string stdout;
    205   ASSERT_TRUE(Subprocess::SynchronousExec(cmd, &rc, &stdout));
    206   EXPECT_EQ(0, rc);
    207   EXPECT_EQ("stdout-herestderr-there", stdout);
    208 }
    209 
    210 TEST_F(SubprocessTest, SynchronousEchoNoOutputTest) {
    211   int rc = -1;
    212   ASSERT_TRUE(Subprocess::SynchronousExec(
    213       {kBinPath "/sh", "-c", "echo test"}, &rc, nullptr));
    214   EXPECT_EQ(0, rc);
    215 }
    216 
    217 namespace {
    218 void CallbackBad(int return_code, const string& output) {
    219   ADD_FAILURE() << "should never be called.";
    220 }
    221 }  // namespace
    222 
    223 // Test that you can cancel a program that's already running.
    224 TEST_F(SubprocessTest, CancelTest) {
    225   base::ScopedTempDir tempdir;
    226   ASSERT_TRUE(tempdir.CreateUniqueTempDir());
    227   string fifo_path = tempdir.GetPath().Append("fifo").value();
    228   EXPECT_EQ(0, mkfifo(fifo_path.c_str(), 0666));
    229 
    230   // Start a process, make sure it is running and try to cancel it. We write
    231   // two bytes to the fifo, the first one marks that the program is running and
    232   // the second one marks that the process waited for a timeout and was not
    233   // killed. We should read the first byte but not the second one.
    234   vector<string> cmd = {
    235       kBinPath "/sh",
    236       "-c",
    237       base::StringPrintf(
    238           // The 'sleep' launched below could be left behind as an orphaned
    239           // process when the 'sh' process is terminated by SIGTERM. As a
    240           // remedy, trap SIGTERM and kill the 'sleep' process, which requires
    241           // launching 'sleep' in background and then waiting for it.
    242           "cleanup() { kill \"${sleep_pid}\"; exit 0; }; "
    243           "trap cleanup TERM; "
    244           "sleep 60 & "
    245           "sleep_pid=$!; "
    246           "printf X >\"%s\"; "
    247           "wait; "
    248           "printf Y >\"%s\"; "
    249           "exit 1",
    250           fifo_path.c_str(),
    251           fifo_path.c_str())};
    252   uint32_t tag = Subprocess::Get().Exec(cmd, base::Bind(&CallbackBad));
    253   EXPECT_NE(0U, tag);
    254 
    255   int fifo_fd = HANDLE_EINTR(open(fifo_path.c_str(), O_RDONLY));
    256   EXPECT_GE(fifo_fd, 0);
    257 
    258   loop_.WatchFileDescriptor(FROM_HERE,
    259                             fifo_fd,
    260                             MessageLoop::WatchMode::kWatchRead,
    261                             false,
    262                             base::Bind([](int fifo_fd, uint32_t tag) {
    263                               char c;
    264                               EXPECT_EQ(1, HANDLE_EINTR(read(fifo_fd, &c, 1)));
    265                               EXPECT_EQ('X', c);
    266                               LOG(INFO) << "Killing tag " << tag;
    267                               Subprocess::Get().KillExec(tag);
    268                             }, fifo_fd, tag));
    269 
    270   // This test would leak a callback that runs when the child process exits
    271   // unless we wait for it to run.
    272   brillo::MessageLoopRunUntil(
    273       &loop_,
    274       TimeDelta::FromSeconds(120),
    275       base::Bind([] { return Subprocess::Get().subprocess_records_.empty(); }));
    276   EXPECT_TRUE(Subprocess::Get().subprocess_records_.empty());
    277   // Check that there isn't anything else to read from the pipe.
    278   char c;
    279   EXPECT_EQ(0, HANDLE_EINTR(read(fifo_fd, &c, 1)));
    280   IGNORE_EINTR(close(fifo_fd));
    281 }
    282 
    283 }  // namespace chromeos_update_engine
    284