Bazel client: abstract away mtime handling

Create an IFileMtime class and platform-specific
implementations to deal with mtime handling.

Since epochs and time granularity vary from
platform to platform, and we only care about
setting a file's/directory's mtime to the current
time or to a future time plus querying whether
something is in the future, we can easily create
an interface for these operations and that's
exactly what IFileMtime is.

Implement PosixFileMtime and WindowsFileMtime.

See https://github.com/bazelbuild/bazel/issues/2107

--
PiperOrigin-RevId: 144956966
MOS_MIGRATED_REVID=144956966

1 files changed, 17 insertions, 17 deletions

diff --git a/src/main/cpp/blaze.cc b/src/main/cpp/blaze.cc
index 594e9aedc5..1aaa117721 100644
--- a/src/main/cpp/blaze.cc
+++ b/src/main/cpp/blaze.cc
@@ -35,7 +35,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
 
 #include <grpc/grpc.h>
 #include <grpc/support/log.h>
@@ -844,9 +843,6 @@ static void ActuallyExtractData(const string &argv0,
         globals->options->product_name.c_str(), extractor->GetError());
   }
 
-  const time_t TEN_YEARS_IN_SEC = 3600 * 24 * 365 * 10;
-  time_t future_time = time(NULL) + TEN_YEARS_IN_SEC;
-
   // Set the timestamps of the extracted files to the future and make sure (or
   // at least as sure as we can...) that the files we have written are actually
   // on the disk.
@@ -856,17 +852,19 @@ static void ActuallyExtractData(const string &argv0,
   // Walks the temporary directory recursively and collects full file paths.
   blaze_util::GetAllFilesUnder(embedded_binaries, &extracted_files);
 
+  std::unique_ptr<blaze_util::IFileMtime> mtime(blaze_util::CreateFileMtime());
   set<string> synced_directories;
   for (const auto &it : extracted_files) {
     const char *extracted_path = it.c_str();
 
     // Set the time to a distantly futuristic value so we can observe tampering.
-    // Note that keeping the default timestamp set by unzip (1970-01-01) and
-    // using that to detect tampering is not enough, because we also need the
-    // timestamp to change between Blaze releases so that the metadata cache
-    // knows that the files may have changed. This is important for actions that
-    // use embedded binaries as artifacts.
-    if (!blaze_util::SetMtimeMillisec(it, future_time)) {
+    // Note that keeping a static, deterministic timestamp, such as the default
+    // timestamp set by unzip (1970-01-01) and using that to detect tampering is
+    // not enough, because we also need the timestamp to change between Bazel
+    // releases so that the metadata cache knows that the files may have
+    // changed. This is essential for the correctness of actions that use
+    // embedded binaries as artifacts.
+    if (!mtime.get()->SetToDistantFuture(it)) {
       pdie(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR,
            "failed to set timestamp on '%s'", extracted_path);
     }
@@ -932,7 +930,8 @@ static void ExtractData(const string &self_path) {
           globals->options->install_base.c_str());
     }
 
-    const time_t time_now = time(NULL);
+    std::unique_ptr<blaze_util::IFileMtime> mtime(
+        blaze_util::CreateFileMtime());
     string real_install_dir = blaze_util::JoinPath(
         globals->options->install_base,
         "_embedded_binaries");
@@ -951,13 +950,14 @@ static void ExtractData(const string &self_path) {
       // Check that the timestamp is in the future. A past timestamp would
       // indicate that the file has been tampered with.
       // See ActuallyExtractData().
-      time_t mtime = blaze_util::GetMtimeMillisec(path);
-      if (mtime == -1) {
+      bool is_in_future = false;
+      if (!mtime.get()->GetIfInDistantFuture(path, &is_in_future)) {
         die(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR,
             "Error: could not retrieve mtime of file '%s'. "
             "Please remove '%s' and try again.",
             path.c_str(), globals->options->install_base.c_str());
-      } else if (mtime <= time_now) {
+      }
+      if (!is_in_future) {
         die(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR,
             "Error: corrupt installation: file '%s' "
             "modified.  Please remove '%s' and try again.",
@@ -1070,9 +1070,9 @@ static void EnsureCorrectRunningVersion(BlazeServer* server) {
 
     // Update the mtime of the install base so that cleanup tools can
     // find install bases that haven't been used for a long time
-    const time_t time_now = time(NULL);
-    if (!blaze_util::SetMtimeMillisec(globals->options->install_base,
-                                      time_now)) {
+    std::unique_ptr<blaze_util::IFileMtime> mtime(
+        blaze_util::CreateFileMtime());
+    if (!mtime.get()->SetToNow(globals->options->install_base)) {
       pdie(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR,
            "failed to set timestamp on '%s'",
            globals->options->install_base.c_str());