1 files changed, 106 insertions, 0 deletions

diff --git a/libprocinfo/include/procinfo/process.h b/libprocinfo/include/procinfo/process.h
new file mode 100644
index 000000000..fb140ff3d
--- /dev/null
+++ b/libprocinfo/include/procinfo/process.h
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <memory>
+#include <string>
+#include <type_traits>
+
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
+#include <android-base/unique_fd.h>
+
+namespace android {
+namespace procinfo {
+
+#if defined(__linux__)
+
+struct ProcessInfo {
+  std::string name;
+  pid_t tid;
+  pid_t pid;
+  pid_t ppid;
+  pid_t tracer;
+  uid_t uid;
+  uid_t gid;
+};
+
+// Parse the contents of /proc/<tid>/status into |process_info|.
+bool GetProcessInfo(pid_t tid, ProcessInfo* process_info);
+
+// Parse the contents of <fd>/status into |process_info|.
+// |fd| should be an fd pointing at a /proc/<pid> directory.
+bool GetProcessInfoFromProcPidFd(int fd, ProcessInfo* process_info);
+
+// Fetch the list of threads from a given process's /proc/<pid> directory.
+// |fd| should be an fd pointing at a /proc/<pid> directory.
+template <typename Collection>
+auto GetProcessTidsFromProcPidFd(int fd, Collection* out) ->
+    typename std::enable_if<sizeof(typename Collection::value_type) >= sizeof(pid_t), bool>::type {
+  out->clear();
+
+  int task_fd = openat(fd, "task", O_DIRECTORY | O_RDONLY | O_CLOEXEC);
+  std::unique_ptr<DIR, int (*)(DIR*)> dir(fdopendir(task_fd), closedir);
+  if (!dir) {
+    PLOG(ERROR) << "failed to open task directory";
+    return false;
+  }
+
+  struct dirent* dent;
+  while ((dent = readdir(dir.get()))) {
+    if (strcmp(dent->d_name, ".") != 0 && strcmp(dent->d_name, "..") != 0) {
+      pid_t tid;
+      if (!android::base::ParseInt(dent->d_name, &tid, 1, std::numeric_limits<pid_t>::max())) {
+        LOG(ERROR) << "failed to parse task id: " << dent->d_name;
+        return false;
+      }
+
+      out->insert(out->end(), tid);
+    }
+  }
+
+  return true;
+}
+
+template <typename Collection>
+auto GetProcessTids(pid_t pid, Collection* out) ->
+    typename std::enable_if<sizeof(typename Collection::value_type) >= sizeof(pid_t), bool>::type {
+  char task_path[PATH_MAX];
+  if (snprintf(task_path, PATH_MAX, "/proc/%d", pid) >= PATH_MAX) {
+    LOG(ERROR) << "task path overflow (pid = " << pid << ")";
+    return false;
+  }
+
+  android::base::unique_fd fd(open(task_path, O_DIRECTORY | O_RDONLY | O_CLOEXEC));
+  if (fd == -1) {
+    PLOG(ERROR) << "failed to open " << task_path;
+    return false;
+  }
+
+  return GetProcessTidsFromProcPidFd(fd.get(), out);
+}
+
+#endif
+
+} /* namespace procinfo */
+} /* namespace android */