src/basic/fdset.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   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 Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 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   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser 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
  26 #include "sd-daemon.h"
  27
  28 #include "fd-util.h"
  29 #include "fdset.h"
  30 #include "macro.h"
  31 #include "set.h"
  32 #include "util.h"
  33
  34 #define MAKE_SET(s) ((Set*) s)
  35 #define MAKE_FDSET(s) ((FDSet*) s)
  36
  37 /* Make sure we can distinguish fd 0 and NULL */
  38 #define FD_TO_PTR(fd) INT_TO_PTR((fd)+1)
  39 #define PTR_TO_FD(p) (PTR_TO_INT(p)-1)
  40
  41 FDSet *fdset_new(void) {
  42         return MAKE_FDSET(set_new(NULL));
  43 }
  44
  45 int fdset_new_array(FDSet **ret, int *fds, unsigned n_fds) {
  46         unsigned i;
  47         FDSet *s;
  48         int r;
  49
  50         assert(ret);
  51
  52         s = fdset_new();
  53         if (!s)
  54                 return -ENOMEM;
  55
  56         for (i = 0; i < n_fds; i++) {
  57
  58                 r = fdset_put(s, fds[i]);
  59                 if (r < 0) {
  60                         set_free(MAKE_SET(s));
  61                         return r;
  62                 }
  63         }
  64
  65         *ret = s;
  66         return 0;
  67 }
  68
  69 FDSet* fdset_free(FDSet *s) {
  70         void *p;
  71
  72         while ((p = set_steal_first(MAKE_SET(s)))) {
  73                 /* Valgrind's fd might have ended up in this set here,
  74                  * due to fdset_new_fill(). We'll ignore all failures
  75                  * here, so that the EBADFD that valgrind will return
  76                  * us on close() doesn't influence us */
  77
  78                 /* When reloading duplicates of the private bus
  79                  * connection fds and suchlike are closed here, which
  80                  * has no effect at all, since they are only
  81                  * duplicates. So don't be surprised about these log
  82                  * messages. */
  83
  84                 log_debug("Closing left-over fd %i", PTR_TO_FD(p));
  85                 close_nointr(PTR_TO_FD(p));
  86         }
  87
  88         set_free(MAKE_SET(s));
  89         return NULL;
  90 }
  91
  92 int fdset_put(FDSet *s, int fd) {
  93         assert(s);
  94         assert(fd >= 0);
  95
  96         return set_put(MAKE_SET(s), FD_TO_PTR(fd));
  97 }
  98
  99 int fdset_consume(FDSet *s, int fd) {
 100         int r;
 101
 102         assert(s);
 103         assert(fd >= 0);
 104
 105         r = fdset_put(s, fd);
 106         if (r <= 0)
 107                 safe_close(fd);
 108
 109         return r;
 110 }
 111
 112 int fdset_put_dup(FDSet *s, int fd) {
 113         int copy, r;
 114
 115         assert(s);
 116         assert(fd >= 0);
 117
 118         copy = fcntl(fd, F_DUPFD_CLOEXEC, 3);
 119         if (copy < 0)
 120                 return -errno;
 121
 122         r = fdset_put(s, copy);
 123         if (r < 0) {
 124                 safe_close(copy);
 125                 return r;
 126         }
 127
 128         return copy;
 129 }
 130
 131 bool fdset_contains(FDSet *s, int fd) {
 132         assert(s);
 133         assert(fd >= 0);
 134
 135         return !!set_get(MAKE_SET(s), FD_TO_PTR(fd));
 136 }
 137
 138 int fdset_remove(FDSet *s, int fd) {
 139         assert(s);
 140         assert(fd >= 0);
 141
 142         return set_remove(MAKE_SET(s), FD_TO_PTR(fd)) ? fd : -ENOENT;
 143 }
 144
 145 int fdset_new_fill(FDSet **_s) {
 146         _cleanup_closedir_ DIR *d = NULL;
 147         struct dirent *de;
 148         int r = 0;
 149         FDSet *s;
 150
 151         assert(_s);
 152
 153         /* Creates an fdset and fills in all currently open file
 154          * descriptors. */
 155
 156         d = opendir("/proc/self/fd");
 157         if (!d)
 158                 return -errno;
 159
 160         s = fdset_new();
 161         if (!s) {
 162                 r = -ENOMEM;
 163                 goto finish;
 164         }
 165
 166         while ((de = readdir(d))) {
 167                 int fd = -1;
 168
 169                 if (hidden_file(de->d_name))
 170                         continue;
 171
 172                 r = safe_atoi(de->d_name, &fd);
 173                 if (r < 0)
 174                         goto finish;
 175
 176                 if (fd < 3)
 177                         continue;
 178
 179                 if (fd == dirfd(d))
 180                         continue;
 181
 182                 r = fdset_put(s, fd);
 183                 if (r < 0)
 184                         goto finish;
 185         }
 186
 187         r = 0;
 188         *_s = s;
 189         s = NULL;
 190
 191 finish:
 192         /* We won't close the fds here! */
 193         if (s)
 194                 set_free(MAKE_SET(s));
 195
 196         return r;
 197 }
 198
 199 int fdset_cloexec(FDSet *fds, bool b) {
 200         Iterator i;
 201         void *p;
 202         int r;
 203
 204         assert(fds);
 205
 206         SET_FOREACH(p, MAKE_SET(fds), i) {
 207                 r = fd_cloexec(PTR_TO_FD(p), b);
 208                 if (r < 0)
 209                         return r;
 210         }
 211
 212         return 0;
 213 }
 214
 215 int fdset_new_listen_fds(FDSet **_s, bool unset) {
 216         int n, fd, r;
 217         FDSet *s;
 218
 219         assert(_s);
 220
 221         /* Creates an fdset and fills in all passed file descriptors */
 222
 223         s = fdset_new();
 224         if (!s) {
 225                 r = -ENOMEM;
 226                 goto fail;
 227         }
 228
 229         n = sd_listen_fds(unset);
 230         for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd ++) {
 231                 r = fdset_put(s, fd);
 232                 if (r < 0)
 233                         goto fail;
 234         }
 235
 236         *_s = s;
 237         return 0;
 238
 239
 240 fail:
 241         if (s)
 242                 set_free(MAKE_SET(s));
 243
 244         return r;
 245 }
 246
 247 int fdset_close_others(FDSet *fds) {
 248         void *e;
 249         Iterator i;
 250         int *a;
 251         unsigned j, m;
 252
 253         j = 0, m = fdset_size(fds);
 254         a = alloca(sizeof(int) * m);
 255         SET_FOREACH(e, MAKE_SET(fds), i)
 256                 a[j++] = PTR_TO_FD(e);
 257
 258         assert(j == m);
 259
 260         return close_all_fds(a, j);
 261 }
 262
 263 unsigned fdset_size(FDSet *fds) {
 264         return set_size(MAKE_SET(fds));
 265 }
 266
 267 bool fdset_isempty(FDSet *fds) {
 268         return set_isempty(MAKE_SET(fds));
 269 }
 270
 271 int fdset_iterate(FDSet *s, Iterator *i) {
 272         void *p;
 273
 274         if (!set_iterate(MAKE_SET(s), i, &p))
 275                 return -ENOENT;
 276
 277         return PTR_TO_FD(p);
 278 }
 279
 280 int fdset_steal_first(FDSet *fds) {
 281         void *p;
 282
 283         p = set_steal_first(MAKE_SET(fds));
 284         if (!p)
 285                 return -ENOENT;
 286
 287         return PTR_TO_FD(p);
 288 }