fdset.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <dirent.h>
  24 #include <fcntl.h>
  25 #include <unistd.h>
  26
  27 #include "set.h"
  28 #include "util.h"
  29 #include "macro.h"
  30 #include "fdset.h"
  31
  32 #define MAKE_SET(s) ((Set*) s)
  33 #define MAKE_FDSET(s) ((FDSet*) s)
  34
  35 /* Make sure we can distuingish fd 0 and NULL */
  36 #define FD_TO_PTR(fd) INT_TO_PTR((fd)+1)
  37 #define PTR_TO_FD(p) (PTR_TO_INT(p)-1)
  38
  39 FDSet *fdset_new(void) {
  40         return MAKE_FDSET(set_new(trivial_hash_func, trivial_compare_func));
  41 }
  42
  43 void fdset_free(FDSet *s) {
  44         void *p;
  45
  46         while ((p = set_steal_first(MAKE_SET(s)))) {
  47                 /* Valgrind's fd might have ended up in this set here,
  48                  * due to fdset_new_fill(). We'll ignore all failures
  49                  * here, so that the EBADFD that valgrind will return
  50                  * us on close() doesn't influence us */
  51
  52                 log_warning("Closing left-over fd %i", PTR_TO_FD(p));
  53                 close_nointr(PTR_TO_FD(p));
  54         }
  55
  56         set_free(MAKE_SET(s));
  57 }
  58
  59 int fdset_put(FDSet *s, int fd) {
  60         assert(s);
  61         assert(fd >= 0);
  62
  63         return set_put(MAKE_SET(s), FD_TO_PTR(fd));
  64 }
  65
  66 int fdset_put_dup(FDSet *s, int fd) {
  67         int copy, r;
  68
  69         assert(s);
  70         assert(fd >= 0);
  71
  72         if ((copy = fcntl(fd, F_DUPFD_CLOEXEC, 3)) < 0)
  73                 return -errno;
  74
  75         if ((r = fdset_put(s, copy)) < 0) {
  76                 close_nointr_nofail(copy);
  77                 return r;
  78         }
  79
  80         return copy;
  81 }
  82
  83 bool fdset_contains(FDSet *s, int fd) {
  84         assert(s);
  85         assert(fd >= 0);
  86
  87         return !!set_get(MAKE_SET(s), FD_TO_PTR(fd));
  88 }
  89
  90 int fdset_remove(FDSet *s, int fd) {
  91         assert(s);
  92         assert(fd >= 0);
  93
  94         return set_remove(MAKE_SET(s), FD_TO_PTR(fd)) ? fd : -ENOENT;
  95 }
  96
  97 int fdset_new_fill(FDSet **_s) {
  98         DIR *d;
  99         struct dirent *de;
 100         int r = 0;
 101         FDSet *s;
 102
 103         assert(_s);
 104
 105         /* Creates an fdsets and fills in all currently open file
 106          * descriptors. */
 107
 108         if (!(d = opendir("/proc/self/fd")))
 109                 return -errno;
 110
 111         if (!(s = fdset_new())) {
 112                 r = -ENOMEM;
 113                 goto finish;
 114         }
 115
 116         while ((de = readdir(d))) {
 117                 int fd = -1;
 118
 119                 if (ignore_file(de->d_name))
 120                         continue;
 121
 122                 if ((r = safe_atoi(de->d_name, &fd)) < 0)
 123                         goto finish;
 124
 125                 if (fd < 3)
 126                         continue;
 127
 128                 if (fd == dirfd(d))
 129                         continue;
 130
 131                 if ((r = fdset_put(s, fd)) < 0)
 132                         goto finish;
 133         }
 134
 135         r = 0;
 136         *_s = s;
 137         s = NULL;
 138
 139 finish:
 140         closedir(d);
 141
 142         /* We won't close the fds here! */
 143         if (s)
 144                 set_free(MAKE_SET(s));
 145
 146         return r;
 147
 148 }
 149
 150 int fdset_cloexec(FDSet *fds, bool b) {
 151         Iterator i;
 152         void *p;
 153         int r;
 154
 155         assert(fds);
 156
 157         SET_FOREACH(p, MAKE_SET(fds), i)
 158                 if ((r = fd_cloexec(PTR_TO_FD(p), b)) < 0)
 159                         return r;
 160
 161         return 0;
 162 }