Home | History | Annotate | Download | only in quipper 
      1 // Copyright 2016 The Chromium OS Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "dso.h"
      6 
      7 #include <elf.h>
      8 #include <fcntl.h>
      9 #include <string.h>
     10 #include <sys/stat.h>
     11 #include <sys/sysmacros.h>
     12 #include <unistd.h>
     13 
     14 #include <algorithm>
     15 #include <vector>
     16 
     17 #include <build_id.h>
     18 #include <read_elf.h>
     19 
     20 #include "base/logging.h"
     21 #include "compat/string.h"
     22 #include "file_reader.h"
     23 
     24 namespace quipper {
     25 
     26 void InitializeLibelf() {
     27   // Unnecessary.
     28 }
     29 
     30 bool ReadElfBuildId(const string &filename, string *buildid) {
     31   BuildId id;
     32   ElfStatus status = GetBuildIdFromElfFile(filename, &id);
     33   if (status == ElfStatus::NO_ERROR) {
     34     *buildid = id.ToString();
     35     return true;
     36   }
     37   return false;
     38 }
     39 
     40 bool ReadElfBuildId(int fd, string *buildid) {
     41   // TODO: Implement. b/74410255.
     42   return false;
     43 }
     44 
     45 // read /sys/module/<module_name>/notes/.note.gnu.build-id
     46 bool ReadModuleBuildId(const string &module_name, string *buildid) {
     47   string note_filename =
     48       "/sys/module/" + module_name + "/notes/.note.gnu.build-id";
     49 
     50   FileReader file(note_filename);
     51   if (!file.IsOpen()) return false;
     52 
     53   return ReadBuildIdNote(&file, buildid);
     54 }
     55 
     56 bool ReadBuildIdNote(DataReader *data, string *buildid) {
     57   // Non-simpleperf implementation, as a reader is given.
     58   Elf64_Nhdr note_header;
     59 
     60   while (data->ReadData(sizeof(note_header), &note_header)) {
     61     size_t name_size = Align<4>(note_header.n_namesz);
     62     size_t desc_size = Align<4>(note_header.n_descsz);
     63 
     64     string name;
     65     if (!data->ReadString(name_size, &name)) return false;
     66     string desc;
     67     if (!data->ReadDataString(desc_size, &desc)) return false;
     68     if (note_header.n_type == NT_GNU_BUILD_ID && name == ELF_NOTE_GNU) {
     69       *buildid = desc;
     70       return true;
     71     }
     72   }
     73   return false;
     74 }
     75 
     76 bool IsKernelNonModuleName(string name) {
     77   // List from kernel: tools/perf/util/dso.c : __kmod_path__parse()
     78   static const std::vector<string> kKernelNonModuleNames{
     79       "[kernel.kallsyms]",
     80       "[guest.kernel.kallsyms",
     81       "[vdso]",
     82       "[vsyscall]",
     83   };
     84 
     85   for (const auto &n : kKernelNonModuleNames) {
     86     if (name.compare(0, n.size(), n) == 0) return true;
     87   }
     88   return false;
     89 }
     90 
     91 // Do the |DSOInfo| and |struct stat| refer to the same inode?
     92 bool SameInode(const DSOInfo &dso, const struct stat *s) {
     93   return dso.maj == major(s->st_dev) && dso.min == minor(s->st_dev) &&
     94          dso.ino == s->st_ino;
     95 }
     96 
     97 }  // namespace quipper
     98