Optimistically read from /proc for process stats.

b/341774149

base/BUILD.gn

@@ -1065,6 +1065,13 @@ component("base") {
     ]
   }
 
+  if (use_cobalt_customizations) {
+    sources += [
+      "process/internal_linux.cc",
+      "process/internal_linux.h",
+    ]
+  }
+
   if (!use_cobalt_customizations && (is_linux || is_chromeos || is_android)) {
     sources += [
       "files/file_path_watcher_inotify.cc",

base/process/internal_linux.cc

@@ -4,8 +4,10 @@
 
 #include "base/process/internal_linux.h"
 
+#if !defined(STARBOARD)
 #include <limits.h>
 #include <unistd.h>
+#endif  // !defined(STARBOARD)
 
 #include <map>
 #include <string>
@@ -33,6 +35,7 @@ const char kProcDir[] = "/proc";
 
 const char kStatFile[] = "stat";
 
+#if !defined(STARBOARD)
 FilePath GetProcPidDir(pid_t pid) {
   return FilePath(kProcDir).Append(NumberToString(pid));
 }
@@ -56,6 +59,7 @@ pid_t ProcDirSlotToPid(const char* d_name) {
   }
   return pid;
 }
+#endif  // !defined(STARBOARD)
 
 bool ReadProcFile(const FilePath& file, std::string* buffer) {
   DCHECK(FilePath(kProcDir).IsParent(file));
@@ -70,10 +74,12 @@ bool ReadProcFile(const FilePath& file, std::string* buffer) {
   return !buffer->empty();
 }
 
+#if !defined(STARBOARD)
 bool ReadProcStats(pid_t pid, std::string* buffer) {
   FilePath stat_file = internal::GetProcPidDir(pid).Append(kStatFile);
   return ReadProcFile(stat_file, buffer);
 }
+#endif  // !defined(STARBOARD)
 
 bool ParseProcStats(const std::string& stats_data,
                     std::vector<std::string>* proc_stats) {
@@ -86,28 +92,29 @@ bool ParseProcStats(const std::string& stats_data,
   // pid (process name) data1 data2 .... dataN
   // Look for the closing paren by scanning backwards, to avoid being fooled by
   // processes with ')' in the name.
-  size_t open_parens_idx = stats_data.find(" (");
-  size_t close_parens_idx = stats_data.rfind(") ");
-  if (open_parens_idx == std::string::npos ||
-      close_parens_idx == std::string::npos ||
-      open_parens_idx > close_parens_idx) {
+  size_t pid_end = stats_data.find(" (");
+  size_t comm_start = pid_end + 2;
+  size_t comm_end = stats_data.rfind(") ");
+  size_t state_start = comm_end + 2;
+  if (pid_end == std::string::npos ||
+      comm_end == std::string::npos ||
+      pid_end > comm_end) {
     DLOG(WARNING) << "Failed to find matched parens in '" << stats_data << "'";
     NOTREACHED();
     return false;
   }
-  open_parens_idx++;
 
   proc_stats->clear();
   // PID.
-  proc_stats->push_back(stats_data.substr(0, open_parens_idx));
+  proc_stats->push_back(stats_data.substr(0, pid_end));
   // Process name without parentheses.
   proc_stats->push_back(
-      stats_data.substr(open_parens_idx + 1,
-                        close_parens_idx - (open_parens_idx + 1)));
+      stats_data.substr(comm_start,
+                        comm_end - comm_start));
 
   // Split the rest.
   std::vector<std::string> other_stats = SplitString(
-      stats_data.substr(close_parens_idx + 2), " ",
+      stats_data.substr(state_start), " ",
       base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
   for (const auto& i : other_stats)
     proc_stats->push_back(i);
@@ -152,16 +159,19 @@ int64_t ReadStatFileAndGetFieldAsInt64(const FilePath& stat_file,
   return GetProcStatsFieldAsInt64(proc_stats, field_num);
 }
 
+#if !defined(STARBOARD)
 int64_t ReadProcStatsAndGetFieldAsInt64(pid_t pid, ProcStatsFields field_num) {
   FilePath stat_file = internal::GetProcPidDir(pid).Append(kStatFile);
   return ReadStatFileAndGetFieldAsInt64(stat_file, field_num);
 }
+#endif  // !defined(STARBOARD)
 
 int64_t ReadProcSelfStatsAndGetFieldAsInt64(ProcStatsFields field_num) {
   FilePath stat_file = FilePath(kProcDir).Append("self").Append(kStatFile);
   return ReadStatFileAndGetFieldAsInt64(stat_file, field_num);
 }
 
+#if !defined(STARBOARD)
 size_t ReadProcStatsAndGetFieldAsSizeT(pid_t pid,
                                        ProcStatsFields field_num) {
   std::string stats_data;
@@ -172,6 +182,7 @@ size_t ReadProcStatsAndGetFieldAsSizeT(pid_t pid,
     return 0;
   return GetProcStatsFieldAsSizeT(proc_stats, field_num);
 }
+#endif  // !defined(STARBOARD)
 
 Time GetBootTime() {
   FilePath path("/proc/stat");
@@ -189,6 +200,7 @@ Time GetBootTime() {
   return Time::FromTimeT(btime);
 }
 
+#if !defined(STARBOARD)
 TimeDelta GetUserCpuTimeSinceBoot() {
   FilePath path("/proc/stat");
   std::string contents;
@@ -228,6 +240,7 @@ TimeDelta ClockTicksToTimeDelta(int64_t clock_ticks) {
 
   return Microseconds(Time::kMicrosecondsPerSecond * clock_ticks / kHertz);
 }
+#endif  // !defined(STARBOARD)
 
 }  // namespace internal
 }  // namespace base

base/process/internal_linux.h

@@ -8,13 +8,17 @@
 #ifndef BASE_PROCESS_INTERNAL_LINUX_H_
 #define BASE_PROCESS_INTERNAL_LINUX_H_
 
+#if !defined(STARBOARD)
 #include <stddef.h>
 #include <stdint.h>
 #include <unistd.h>
+#endif  // !defined(STARBOARD)
 #include <string>
 #include <vector>
 
+#if !defined(STARBOARD)
 #include "base/files/dir_reader_posix.h"
+#endif  // !defined(STARBOARD)
 #include "base/files/file_path.h"
 #include "base/process/process_handle.h"
 #include "base/strings/string_number_conversions.h"
@@ -33,14 +37,17 @@ extern const char kProcDir[];
 // "stat"
 extern const char kStatFile[];
 
+#if !defined(STARBOARD)
 // Returns a FilePath to "/proc/pid".
 base::FilePath GetProcPidDir(pid_t pid);
+#endif  // !defined(STARBOARD)
 
 // Reads a file from /proc into a string. This is allowed on any thread as
 // reading from /proc does not hit the disk. Returns true if the file can be
 // read and is non-empty.
 bool ReadProcFile(const FilePath& file, std::string* buffer);
 
+#if !defined(STARBOARD)
 // Take a /proc directory entry named |d_name|, and if it is the directory for
 // a process, convert it to a pid_t.
 // Returns 0 on failure.
@@ -50,6 +57,7 @@ pid_t ProcDirSlotToPid(const char* d_name);
 // Reads /proc/<pid>/stat into |buffer|. Returns true if the file can be read
 // and is non-empty.
 bool ReadProcStats(pid_t pid, std::string* buffer);
+#endif  // !defined(STARBOARD)
 
 // Takes |stats_data| and populates |proc_stats| with the values split by
 // spaces. Taking into account the 2nd field may, in itself, contain spaces.
@@ -89,16 +97,21 @@ size_t GetProcStatsFieldAsSizeT(const std::vector<std::string>& proc_stats,
 // ReadProcStats(). See GetProcStatsFieldAsInt64() for details.
 int64_t ReadStatsFilendGetFieldAsInt64(const FilePath& stat_file,
                                        ProcStatsFields field_num);
+#if !defined(STARBOARD)
 int64_t ReadProcStatsAndGetFieldAsInt64(pid_t pid, ProcStatsFields field_num);
+#endif  // !defined(STARBOARD)
 int64_t ReadProcSelfStatsAndGetFieldAsInt64(ProcStatsFields field_num);
 
+#if !defined(STARBOARD)
 // Same as ReadProcStatsAndGetFieldAsInt64() but for size_t values.
 size_t ReadProcStatsAndGetFieldAsSizeT(pid_t pid,
                                        ProcStatsFields field_num);
+#endif  // !defined(STARBOARD)
 
 // Returns the time that the OS started. Clock ticks are relative to this.
 Time GetBootTime();
 
+#if !defined(STARBOARD)
 // Returns the amount of time spent in user space since boot across all CPUs.
 TimeDelta GetUserCpuTimeSinceBoot();
 
@@ -130,6 +143,7 @@ void ForEachProcessTask(base::ProcessHandle process, Lambda&& lambda) {
     lambda(tid, task_path);
   }
 }
+#endif  // !defined(STARBOARD)
 
 }  // namespace internal
 }  // namespace base

cobalt/base/BUILD.gn

@@ -67,6 +67,8 @@ static_library("base") {
     "path_provider.h",
     "polymorphic_downcast.h",
     "polymorphic_equatable.h",
+    "process/process_metrics_helper.cc",
+    "process/process_metrics_helper.h",
     "ref_counted_lock.h",
     "source_location.cc",
     "source_location.h",
@@ -117,6 +119,7 @@ target(gtest_target_type, "base_test") {
     "c_val_time_interval_timer_stats_test.cc",
     "circular_buffer_shell_unittest.cc",
     "fixed_size_lru_cache_test.cc",
+    "process/process_metrics_helper_test.cc",
     "statistics_test.cc",
     "token_test.cc",
   ]