/afs/cern.ch/work/a/aaltunda/public/www/CMSSW_5_3_14/src/Utilities/StorageFactory/src/LocalFileSystem.cc

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#define _GNU_SOURCE 1
#define _FILE_OFFSET_BITS 64
#include "Utilities/StorageFactory/interface/LocalFileSystem.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <sys/param.h>
#if BSD
# include <sys/statvfs.h>
# include <sys/ucred.h>
# include <sys/mount.h>
#else
# include <mntent.h>
# include <sys/vfs.h>
#endif
#include <sys/stat.h>
#include <unistd.h>
#include <iostream>

#pragma GCC diagnostic ignored "-Wformat" // shut warning on '%z'

struct LocalFileSystem::FSInfo
{
  char          *fsname;        //< file system name
  char          *type;          //< file system type
  char          *dir;           //< mount point directory
  dev_t         dev;            //< device id
  long          fstype;         //< file system id
  double        freespc;        //< free space in megabytes
  unsigned      local : 1;      //< flag for local device
  unsigned      checked : 1;    //< flag for valid dev, fstype
};

int
LocalFileSystem::readFSTypes(void)
{
  int ret = 0;

#if __linux__
  static const char procfs[] = "/proc/filesystems";
  FILE *fs = fopen(procfs, "r");
  if (! fs)
  {
    int nerr = errno;
    edm::LogWarning("LocalFileSystem::readFSTypes()")
      << "Cannot read '" << procfs << "': "
      << strerror(nerr) << " (error " << nerr << ")";
    return -1;
  }

  ssize_t nread;
  int line = 0;
  while (! feof(fs))
  {
    char *type = 0;
    char *fstype = 0;
    size_t len = 0;
    ++line;

    if ((nread = getdelim(&type, &len, '\t', fs)) == -1 && ! feof(fs))
    {
      fprintf(stderr, "%s:%d: %s (%zd; 1)\n",
              procfs, line, strerror(errno), nread);
      free(type);
      ret = -1;
      break;
    }

    if ((nread = getdelim(&fstype, &len, '\n', fs)) == -1 && ! feof(fs))
    {
      fprintf(stderr, "%s:%d: %s (%zd; 2)\n",
              procfs, line, strerror(errno), nread);
      free(type);
      free(fstype);
      ret = -1;
      break;
    }

    if (feof (fs))
    {
      free(type);
      free(fstype);
      break;
    }
    
    if (! strcmp(type, "nodev\t")
        || ! strcmp(fstype, "lustre\n")
        || ! strncmp(fstype, "fuse", 4))
    {
      free(type);
      free(fstype);
      continue;
    }

    assert(nread >= 1);
    fstype[nread-1] = 0;
    fstypes_.push_back(fstype);
    free(fstype);
    free(type);
  }

  fclose(fs);
#endif // __linux__

  return ret;
}

LocalFileSystem::FSInfo *
LocalFileSystem::initFSInfo(void *arg)
{
#if BSD
  struct statfs *m = static_cast<struct statfs *>(arg);
  size_t infolen = sizeof(struct FSInfo);
  size_t fslen = strlen(m->f_mntfromname) + 1;
  size_t dirlen = strlen(m->f_mntonname) + 1;
  size_t typelen = strlen(m->f_fstypename) + 1;
  size_t totlen = infolen + fslen + dirlen + typelen;
  FSInfo *i = (FSInfo *) malloc(totlen);
  char *p = (char *) i;
  i->fsname = strncpy(p += infolen, m->f_mntfromname, fslen);
  i->type = strncpy(p += fslen, m->f_fstypename, typelen);
  i->dir = strncpy(p += typelen, m->f_mntonname, dirlen);
  i->dev = m->f_fsid.val[0];
  i->fstype = m->f_type;
  i->freespc = 0;
  if (m->f_bsize > 0)
  {
    i->freespc = m->f_bavail;
    i->freespc *= m->f_bsize;
    i->freespc /= 1024. * 1024. * 1024.;
  } 
  /* FIXME: This incorrectly says that mounted disk images are local,
     even if it was mounted from a network server. The alternative is
     to walk up the device tree using either a) process IORegistry to
     get the device tree, which lists devices for disk images, and from
     there translate volume uuid to a mount point; b) parse output from
     'hdiutil info -plist' to determine image-path / dev-entry map. */
  i->local = ((m->f_flags & MNT_LOCAL) ? 1 : 0);
  i->checked = 1;
  return i;

#else // ! BSD
  mntent *m = static_cast<mntent *>(arg);
  size_t infolen = sizeof(struct FSInfo);
  size_t fslen = strlen(m->mnt_fsname) + 1;
  size_t dirlen = strlen(m->mnt_dir) + 1;
  size_t typelen = strlen(m->mnt_type) + 1;
  size_t totlen = infolen + fslen + dirlen + typelen;
  FSInfo *i = (FSInfo *) malloc(totlen);
  char *p = (char *) i;
  i->fsname = strncpy(p += infolen, m->mnt_fsname, fslen);
  i->type = strncpy(p += fslen, m->mnt_type, typelen);
  i->dir = strncpy(p += typelen, m->mnt_dir, dirlen);
  i->dev = -1;
  i->fstype = -1;
  i->freespc = 0;
  i->local = 0;
  i->checked = 0;

  for (size_t j = 0; j < fstypes_.size() && ! i->local; ++j)
    if (fstypes_[j] == i->type)
      i->local = 1;
#endif // BSD

  return i;
}

int
LocalFileSystem::initFSList(void)
{
#if BSD
  int rc;
  struct statfs *mtab = 0;
  if ((rc = getmntinfo(&mtab, MNT_NOWAIT)) < 0)
  {
    int nerr = errno;
    edm::LogWarning("LocalFileSystem::initFSList()")
      << "getmntinfo() failed: " << strerror(nerr)
      << " (error " << nerr << ")";
    return -1;
  }

  fs_.reserve(rc);
  for (int ix = 0; ix < rc; ++ix)
    fs_.push_back(initFSInfo(&mtab[ix]));

  free(mtab);
#else
  struct mntent *m;
  FILE *mtab = setmntent(_PATH_MOUNTED, "r");
  if (! mtab)
  {
    int nerr = errno;
    edm::LogWarning("LocalFileSystem::initFSList()")
      << "Cannot read '" << _PATH_MOUNTED << "': "
      << strerror(nerr) << " (error " << nerr << ")";
    return -1;
  }

  fs_.reserve(20);
  while ((m = getmntent(mtab)))
    fs_.push_back(initFSInfo(m));

  endmntent(mtab);
#endif

  return 0;
}

int
LocalFileSystem::statFSInfo(FSInfo *i)
{
  int ret = 0;
  struct stat s;
  struct statfs sfs;

  if (! i->checked)
  {
    i->checked = 1;
    if (lstat(i->dir, &s) < 0)
    {
      int nerr = errno;
      if (nerr != ENOENT && nerr != EACCES)
        edm::LogWarning("LocalFileSystem::statFSInfo()")
          << "Cannot lstat('" << i->dir << "'): "
          << strerror(nerr) << " (error " << nerr << ")";
      return -1;
    }

    if (statfs(i->dir, &sfs) < 0)
    {
      int nerr = errno;
      edm::LogWarning("LocalFileSystem::statFSInfo()")
        << "Cannot statfs('" << i->dir << "'): "
        << strerror(nerr) << " (error " << nerr << ")";
      return -1;
    }

    i->dev = s.st_dev;
    i->fstype = sfs.f_type;
    if (sfs.f_bsize > 0)
    {
      i->freespc = sfs.f_bavail;
      i->freespc *= sfs.f_bsize;
      i->freespc /= 1024. * 1024. * 1024.;
    }
  }
  else if (i->fstype == -1)
  {
    errno = ENOENT;
    ret = -1;
  }

  return ret;
}

LocalFileSystem::FSInfo *
LocalFileSystem::findMount(const char *path, struct statfs *sfs, struct stat *s)
{
  FSInfo *best = 0;
  size_t bestlen = 0;
  size_t len = strlen(path);
  for (size_t i = 0; i < fs_.size(); ++i)
  {
    // First match simply against the file system path.  We don't
    // touch the file system until the path prefix matches.
    size_t fslen = strlen(fs_[i]->dir);
    if (! strncmp(fs_[i]->dir, path, fslen)
        && ((fslen == 1 && fs_[i]->dir[0] == '/')
            || len == fslen || path[fslen] == '/')
        && (! best || fslen > bestlen))
    {
      // Get the file system device and file system ids.
      if (statFSInfo(fs_[i]) < 0)
        return 0;

      // Check the path is on the same device / file system.  If this
      // fails, we found a better prefix match on path, but it's the
      // wrong device, so reset our idea of the best match: it can't
      // be the outer mount any more.  Not sure this is the right
      // thing to do with e.g. loop-back or union mounts.
      if (fs_[i]->dev != s->st_dev || fs_[i]->fstype != sfs->f_type)
      {
        best = 0;
        continue;
      }

      // OK this is better than anything else we found so far.
      best = fs_[i];
      bestlen = fslen;
    }
  }

  return best;
}

bool
LocalFileSystem::isLocalPath(const std::string &path)
{
  struct stat s;
  struct statfs sfs;
  char *fullpath = realpath(path.c_str(), 0);

  if (! fullpath)
    fullpath = strdup(path.c_str());

  if (lstat(fullpath, &s) < 0)
  {
    int nerr = errno;
    edm::LogWarning("LocalFileSystem::isLocalPath()")
      << "Cannot lstat('" << fullpath << "' alias '"
      << path << "'): " << strerror(nerr) << " (error "
      << nerr << ")";
    free(fullpath);
    return false;
  }
    
  if (statfs(fullpath, &sfs) < 0)
  {
    int nerr = errno;
    edm::LogWarning("LocalFileSystem::isLocalPath()")
      << "Cannot statfs('" << fullpath << "' alias '"
      << path << "'): " << strerror(nerr) << " (error "
      << nerr << ")";
    free(fullpath);
    return false;
  }

  FSInfo *m = findMount(fullpath, &sfs, &s);
  free(fullpath);

  return m ? m->local : false;
}

std::string
LocalFileSystem::findCachePath(const std::vector<std::string> &paths,
                               double minFreeSpace)
{
  struct stat s;
  struct statfs sfs;
  for (size_t i = 0, e = paths.size(); i < e; ++i)
  {
    char *fullpath;
    const char *inpath = paths[i].c_str();
    const char *path = inpath;

    if (*path == '$')
    {
      char *p = getenv(path+1);
      if (p && *p)
        path = p;
      else if (! strcmp(path, "$TMPDIR"))
        path = "/tmp";
    }

    if (! (fullpath = realpath(path, 0)))
      fullpath = strdup(path);

#if 0
    std::cerr /* edm::LogInfo("LocalFileSystem") */
      << "Checking if '" << fullpath << "', from '"
      << inpath << "' is valid cache path with "
      << minFreeSpace << " free space" << std::endl;
#endif

    if (lstat(fullpath, &s) < 0)
    {
      int nerr = errno;
      if (nerr != ENOENT && nerr != EACCES)
        edm::LogWarning("LocalFileSystem::findCachePath()")
          << "Cannot lstat('" << fullpath << "', from '"
          << inpath << "'): " << strerror(nerr) << " (error "
          << nerr << ")";
      free(fullpath);
      continue;
    }
    
    if (statfs(fullpath, &sfs) < 0)
    {
      int nerr = errno;
      edm::LogWarning("LocalFileSystem::findCachePath()")
        << "Cannot statfs('" << fullpath << "', from '"
        << inpath << "'): " << strerror(nerr) << " (error "
        << nerr << ")";
      free(fullpath);
      continue;
    }

    FSInfo *m = findMount(fullpath, &sfs, &s);
#if 0
    std::cerr /* edm::LogInfo("LocalFileSystem") */
      << "Candidate '" << fullpath << "': "
      << "found=" << (m ? 1 : 0)
      << " local=" << (m && m->local)
      << " free=" << (m ? m->freespc : 0)
      << " access=" << access(fullpath, W_OK)
      << std::endl;
#endif

    if (m
        && m->local
        && m->freespc >= minFreeSpace
        && access(fullpath, W_OK) == 0)
    {
      std::string result(fullpath);
      free(fullpath);
      return result;
    }

    free(fullpath);
  }

  return std::string();
}

LocalFileSystem::LocalFileSystem(void)
{
  if (readFSTypes() < 0)
    return;

  if (initFSList() < 0)
    return;
}

LocalFileSystem::~LocalFileSystem(void)
{
  for (size_t i = 0, e = fs_.size(); i < e; ++i)
    free(fs_[i]);
}