Update Crashpad to b47bf6c250c6b825dee1c5fbad9152c2c962e828

third_party/crashpad/crashpad/test/paths_linux.cc

+// Copyright 2016 The Crashpad Authors. All rights reserved.
+//
+// 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 "test/paths.h"
+
+#include <limits.h>
+#include <unistd.h>
+
+#include <algorithm>
+#include <string>
+
+#include "base/logging.h"
+#include "util/misc/implicit_cast.h"
+
+namespace crashpad {
+namespace test {
+
+// static
+base::FilePath Paths::Executable() {
+  // Linux does not provide a straightforward way to size the buffer before
+  // calling readlink(). Normally, the st_size field returned by lstat() could
+  // be used, but this is usually zero for things in /proc.
+  //
+  // The /proc filesystem does not provide any way to read “exe” links for
+  // pathnames longer than a page. See linux-4.4.27/fs/proc/base.c
+  // do_proc_readlink(), which allocates a single page to receive the path
+  // string. Coincidentally, the page size and PATH_MAX are normally the same
+  // value, although neither is strictly a limit on the length of a pathname.
+  //
+  // On Android, the smaller of the page size and PATH_MAX actually does serve
+  // as an effective limit on the length of an executable’s pathname. See
+  // Android 7.0.0 bionic/linker/linker.cpp get_executable_path(), which aborts
+  // via __libc_fatal() if the “exe” link can’t be read into a PATH_MAX-sized
+  // buffer.
+  std::string exe_path(std::max(implicit_cast<size_t>(sysconf(_SC_PAGESIZE)),
+                                implicit_cast<size_t>(PATH_MAX)),
+                       std::string::value_type());
+  ssize_t exe_path_len =
+      readlink("/proc/self/exe", &exe_path[0], exe_path.size());
+  if (exe_path_len < 0) {
+    PLOG(FATAL) << "readlink";
+  } else if (static_cast<size_t>(exe_path_len) >= exe_path.size()) {
+    LOG(FATAL) << "readlink";
+  }
+
+  exe_path.resize(exe_path_len);
+  return base::FilePath(exe_path);
+}
+
+}  // namespace test
+}  // namespace crashpad