io/tst-fcntl-lock.c

   1 /* Test for advisory record locking.
   2    Copyright (C) 2023 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU General Public License
   6    as published by the Free Software Foundation; either version 2
   7    of the License, or (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, see <https://www.gnu.org/licenses/>.
  16 */
  17
  18 #include <fcntl.h>
  19 #include <errno.h>
  20 #include <unistd.h>
  21
  22 /* This is essentially the POSIX lockf.  */
  23
  24 static int
  25 fcntl_lockf (int fd, int cmd, off_t len)
  26 {
  27   struct flock fl = {
  28     .l_type = F_WRLCK,
  29     .l_whence = SEEK_CUR,
  30     .l_len = len
  31   };
  32
  33   switch (cmd)
  34     {
  35     case F_TEST:
  36       fl.l_type = F_RDLCK;
  37       if (fcntl (fd, F_GETLK, &fl) < 0)
  38         return -1;
  39       if (fl.l_type == F_UNLCK || fl.l_pid == getpid ())
  40         return 0;
  41       errno = EACCES;
  42       return -1;
  43
  44     case F_ULOCK:
  45       fl.l_type = F_UNLCK;
  46       return fcntl (fd, F_SETLK, &fl);
  47
  48     case F_LOCK:
  49       return fcntl (fd, F_SETLKW, &fl);
  50
  51     case F_TLOCK:
  52       return fcntl (fd, F_SETLK, &fl);
  53     }
  54
  55   errno = EINVAL;
  56   return -1;
  57 }
  58
  59 static int
  60 fcntl64_lockf (int fd, int cmd, off64_t len64)
  61   {
  62   struct flock64 fl64 = {
  63     .l_type = F_WRLCK,
  64     .l_whence = SEEK_CUR,
  65     .l_len = len64
  66   };
  67
  68   switch (cmd)
  69     {
  70     case F_TEST:
  71       fl64.l_type = F_RDLCK;
  72       if (fcntl64 (fd, F_GETLK64, &fl64) < 0)
  73         return -1;
  74       if (fl64.l_type == F_UNLCK || fl64.l_pid == getpid ())
  75         return 0;
  76       errno = EACCES;
  77       return -1;
  78
  79     case F_ULOCK:
  80       fl64.l_type = F_UNLCK;
  81       return fcntl64 (fd, F_SETLK64, &fl64);
  82
  83     case F_LOCK:
  84       return fcntl64 (fd, F_SETLKW64, &fl64);
  85
  86     case F_TLOCK:
  87       return fcntl64 (fd, F_SETLK64, &fl64);
  88     }
  89
  90   errno = EINVAL;
  91   return -1;
  92 }
  93
  94 #define TST_LOCKFD  "tst-fcntl-lock."
  95 #define LOCKF       fcntl_lockf
  96 #define LOCKF64     fcntl64_lockf
  97 #include "tst-lockf.c"