src/basic/inotify-util.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "fd-util.h"
   4 #include "inotify-util.h"
   5 #include "stat-util.h"
   6
   7 bool inotify_event_next(
   8                 union inotify_event_buffer *buffer,
   9                 size_t size,
  10                 struct inotify_event **iterator,
  11                 int log_level) {
  12
  13         struct inotify_event *e;
  14         size_t offset = 0;
  15
  16         assert(buffer);
  17         assert(iterator);
  18
  19         if (*iterator) {
  20                 assert((uint8_t*) *iterator >= buffer->raw);
  21                 offset = (uint8_t*) *iterator - buffer->raw;
  22                 offset += offsetof(struct inotify_event, name) + (*iterator)->len;
  23         }
  24
  25         if (size == offset)
  26                 return false; /* reached end of list */
  27
  28         if (size < offset ||
  29             size - offset < offsetof(struct inotify_event, name)) {
  30                 log_full(log_level, "Received invalid inotify event, ignoring.");
  31                 return false;
  32         }
  33
  34         e = CAST_ALIGN_PTR(struct inotify_event, buffer->raw + offset);
  35         if (size - offset - offsetof(struct inotify_event, name) < e->len) {
  36                 log_full(log_level, "Received invalid inotify event, ignoring.");
  37                 return false;
  38         }
  39
  40         *iterator = e;
  41         return true;
  42 }
  43
  44 int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
  45         int wd, r;
  46
  47         /* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */
  48         wd = inotify_add_watch(fd, FORMAT_PROC_FD_PATH(what), mask);
  49         if (wd < 0) {
  50                 if (errno != ENOENT)
  51                         return -errno;
  52
  53                 /* Didn't work with ENOENT? If so, then either /proc/ isn't mounted, or the fd is bad */
  54                 r = proc_mounted();
  55                 if (r == 0)
  56                         return -ENOSYS;
  57                 if (r > 0)
  58                         return -EBADF;
  59
  60                 return -ENOENT; /* OK, no clue, let's propagate the original error */
  61         }
  62
  63         return wd;
  64 }
  65
  66 int inotify_add_watch_and_warn(int fd, const char *pathname, uint32_t mask) {
  67         int wd;
  68
  69         wd = inotify_add_watch(fd, pathname, mask);
  70         if (wd < 0) {
  71                 if (errno == ENOSPC)
  72                         return log_error_errno(errno, "Failed to add a watch for %s: inotify watch limit reached", pathname);
  73
  74                 return log_error_errno(errno, "Failed to add a watch for %s: %m", pathname);
  75         }
  76
  77         return wd;
  78 }