xapian-core/tests/harness/fdtracker.cc

   1 /** @file fdtracker.cc
   2  * @brief Track leaked file descriptors.
   3  */
   4 /* Copyright (C) 2010,2014,2015,2018 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of the
   9  * License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #include <config.h>
  22
  23 #include "fdtracker.h"
  24
  25 #ifdef XAPIAN_TESTSUITE_TRACK_FDS
  26
  27 #include "safeunistd.h"
  28 #include "safedirent.h"
  29 #include "safeerrno.h"
  30
  31 #include <iostream>
  32 #include <cstdlib>
  33 #include <cstring> // For strerror().
  34 #include <set>
  35
  36 #include "str.h"
  37 #include "stringutils.h"
  38
  39 using namespace std;
  40
  41 // Directory to try to read open fds from.  If this directory doesn't exist
  42 // then fd tracking will just be disabled.  It seems "/dev/fd" is the more
  43 // common name for this.  On Linux and Cygwin, "/dev/fd" is usually a symlink
  44 // to "/proc/self/fd", but that symlink can sometimes be missing so prefer
  45 // the latter on these platforms.
  46 #if defined __linux__ || defined __CYGWIN__
  47 # define FD_DIRECTORY "/proc/self/fd"
  48 #else
  49 # define FD_DIRECTORY "/dev/fd"
  50 #endif
  51
  52 FDTracker::~FDTracker()
  53 {
  54     if (dir_void) {
  55         DIR * dir = static_cast<DIR*>(dir_void);
  56         closedir(dir);
  57     }
  58 }
  59
  60 void
  61 FDTracker::init()
  62 {
  63     DIR * dir = opendir(FD_DIRECTORY);
  64     // Not all platforms have such a directory.
  65     if (!dir) return;
  66     dir_void = static_cast<void*>(dir);
  67
  68     while (true) {
  69         errno = 0;
  70         struct dirent * entry = readdir(dir);
  71         if (!entry) {
  72             if (errno == 0)
  73                 break;
  74             cout << "readdir failed: " << strerror(errno) << endl;
  75             exit(1);
  76         }
  77
  78         const char * name = entry->d_name;
  79
  80         // Ignore at least '.' and '..'.
  81         if (name[0] < '0' || name[0] > '9')
  82             continue;
  83
  84         int fd = atoi(name);
  85         fds.insert(fd);
  86     }
  87 }
  88
  89 bool
  90 FDTracker::check()
  91 {
  92     bool ok = true;
  93     DIR * dir = static_cast<DIR*>(dir_void);
  94     if (!dir) return true;
  95     rewinddir(dir);
  96
  97     message.resize(0);
  98
  99     while (true) {
 100         errno = 0;
 101         struct dirent * entry = readdir(dir);
 102         if (!entry) {
 103             if (errno == 0)
 104                 break;
 105             cout << "readdir failed: " << strerror(errno) << endl;
 106             exit(1);
 107         }
 108
 109         const char * name = entry->d_name;
 110
 111         // Ignore at least '.' and '..'.
 112         if (name[0] < '0' || name[0] > '9')
 113             continue;
 114
 115         int fd = atoi(name);
 116         if (fds.find(fd) != fds.end()) continue;
 117
 118         string proc_symlink = FD_DIRECTORY "/";
 119         proc_symlink += name;
 120
 121         char buf[1024];
 122         // On some systems (Solaris, AIX) the entries aren't symlinks, so
 123         // don't complain if readlink() fails.
 124         int res = readlink(proc_symlink.c_str(), buf, sizeof(buf));
 125         if (res == CONST_STRLEN("/dev/urandom") &&
 126             memcmp(buf, "/dev/urandom", CONST_STRLEN("/dev/urandom")) == 0) {
 127             // /dev/urandom isn't a real leak - something in the C library
 128             // opens it lazily (at least on Linux).
 129             fds.insert(fd);
 130             continue;
 131         }
 132
 133         message += ' ';
 134         message += str(fd);
 135         if (res > 0) {
 136             message += " -> ";
 137             message.append(buf, res);
 138         }
 139
 140         // Insert the leaked fd so we don't report it for future tests.
 141         fds.insert(fd);
 142         ok = false;
 143     }
 144     return ok;
 145 }
 146
 147 #endif // XAPIAN_TESTSUITE_TRACK_FDS