procmaps.cxx

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/*
  Copyright (C) 2002-2022 CERN for the benefit of the ATLAS collaboration
*/
 
#include <algorithm>
#include <cstdlib>
#include <cstring>
#include <cstdint>
#include <fstream>
#include "CxxUtils/procmaps.h"
procmaps::Entry::Entry(const char* procMapsLine) :
  begAddress(0),endAddress(0),
  readable(false), writable(false), executable(false), isPrivate(false),
  offset(0), inode(0)
{
  dev[0]=0; dev[1]=0;
  char pageProts[5];
  memset(pageProts,' ', 4);
  uint64_t inode_tmp;
  char path[2048] = "";
  sscanf(procMapsLine,
     "%80lx-%80lx %4s %80x %4x:%4x %80lu %2047s",
     &this->begAddress,
     &this->endAddress,
     pageProts,
     &this->offset,
     &this->dev[0],
     &this->dev[1],
     &inode_tmp,
     path
     );
  this->inode = inode_tmp;
  this->pathname = std::string (path);
  //printf("pageProts %s pathname <%s> \n", pageProts, pathname);
  this->readable = (pageProts[0] == 'r');
  this->writable = (pageProts[1] == 'w');
  this->executable = (pageProts[2] == 'x');
  this->isPrivate  = (pageProts[3] == 'p');
}
 
procmaps::procmaps(size_t entries) {
  m_pmaps.reserve(entries);
  loadMaps(false);
}
 
void 
procmaps::loadMaps(bool dump) {
  m_pmaps.clear();
  std::ifstream f("/proc/self/maps");
  const int LMAX=256;
  char line[LMAX];
  while ( f.getline(line,LMAX) ) {
    if (dump) printf("%s",line);
   m_pmaps.emplace_back(line);
  }
}
 
const procmaps::Entry*
procmaps::getEntry(const void * address, bool refreshMaps) {
  unsigned long toMatch = reinterpret_cast<unsigned long>(address);
  auto i = std::upper_bound (this->begin(), this->end(),
                             toMatch,
                             [] (unsigned long addr, const Entry& ent)
                             { return addr < ent.begAddress; });
 
  if (i > this->begin()) {
    --i;
    if (toMatch >= i->begAddress && toMatch < i->endAddress) {
      return &*i;
    }
  }
 
  if (refreshMaps) {
    //if ! found recurse once by calling getEntry with refreshMaps false
    loadMaps();
    return getEntry(address,false);
  }
 
  return nullptr;
}