Implement /proc/self/maps/ parsing code.

base/debug/proc_maps_linux.cc

Index: base/debug/proc_maps_linux.cc
diff --git a/base/debug/proc_maps_linux.cc b/base/debug/proc_maps_linux.cc
new file mode 100644
index 0000000000000000000000000000000000000000..cb2a0fdb29d4380bf8cdc51b6a24115c0310ea7c
--- /dev/null
+++ b/base/debug/proc_maps_linux.cc
@@ -0,0 +1,99 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/debug/proc_maps_linux.h"
+
+#if defined(OS_LINUX)
+#include <inttypes.h>
+#endif
+
+#if defined(OS_ANDROID)
+// Bionic's inttypes.h defines PRI/SCNxPTR as an unsigned long int, which
+// is incompatible with Bionic's stdint.h defining uintptr_t as a unsigned int:
+// https://code.google.com/p/android/issues/detail?id=57218
+#define SCNxPTR "x"

[Mark Mentovai, 2013/07/02 22:21:36]

You might want to #undef SCNxPTR before this, in case something else #includes
the bum <inttypes.h> before reaching here.

If you do that, you should move this OS_ANDROID block below all of the other
#includes.

[scherkus (not reviewing), 2013/07/02 23:07:47]

Done.

+#endif
+
+#include "base/file_util.h"
+#include "base/strings/string_split.h"
+
+namespace base {
+namespace debug {
+
+bool ReadProcMaps(std::string* proc_maps) {
+  FilePath proc_maps_path("/proc/self/maps");
+  return file_util::ReadFileToString(proc_maps_path, proc_maps);
+}
+
+bool ParseProcMaps(const std::string& input,
+                   std::vector<MappedMemoryRegion>* regions_out) {
+  std::vector<MappedMemoryRegion> regions;
+
+  // This isn't async safe nor terribly efficient, but it doesn't need to be at
+  // this point in time.
+  std::vector<std::string> lines;
+  SplitString(input, '\n', &lines);
+
+  for (size_t i = 0; i < lines.size(); ++i) {
+    // Due to splitting on '\n' the last line should be empty.
+    if (i == lines.size() - 1) {
+      if (!lines[i].empty())
+        return false;
+      break;
+    }
+
+    MappedMemoryRegion region;
+    const char* line = lines[i].c_str();
+    char permissions[5] = {'\0'};  // Ensure NUL-terminated string.
+    uint8 dev_major = 0;
+    uint8 dev_minor = 0;
+    long inode = 0;
+    int path_index = 0;
+
+    // Sample format from man 5 proc:
+    //
+    // address           perms offset  dev   inode   pathname
+    // 08048000-08056000 r-xp 00000000 03:0c 64593   /usr/sbin/gpm
+    //
+    // The final %n term captures the offset in the input string, which is used
+    // to determine the path name. It *does not* increment the return value.
+    // Refer to man 3 sscanf for details.
+    if (sscanf(line, "%" SCNxPTR "-%" SCNxPTR " %4c %llx %hhx:%hhx %ld %n",
+               &region.start, &region.end, permissions, &region.offset,
+               &dev_major, &dev_minor, &inode, &path_index) < 7) {
+      return false;
+    }
+
+    region.permissions = 0;
+
+    if (permissions[0] == 'r')
+      region.permissions |= MappedMemoryRegion::READ;
+    else if (permissions[0] != '-')
+      return false;
+
+    if (permissions[1] == 'w')
+      region.permissions |= MappedMemoryRegion::WRITE;
+    else if (permissions[1] != '-')
+      return false;
+
+    if (permissions[2] == 'x')
+      region.permissions |= MappedMemoryRegion::EXECUTE;
+    else if (permissions[2] != '-')
+      return false;
+
+    if (permissions[3] == 'p')
+      region.permissions |= MappedMemoryRegion::PRIVATE;
+    else if (permissions[3] != 's' && permissions[3] != 'S')  // Shared memory.
+      return false;
+
+    regions.push_back(region);
+    regions.back().path.assign(line + path_index);

[Mark Mentovai, 2013/07/02 22:21:36]

Comment “this weird thing saves a string copy?”

[scherkus (not reviewing), 2013/07/02 23:07:47]

Done.

+  }
+
+  regions_out->swap(regions);
+  return true;
+}
+
+}  // namespace debug
+}  // namespace base