sysdeps/unix/sysv/linux/prlimit.c

   1 /* Copyright (C) 2010-2018 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library 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 GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <sys/resource.h>
  20 #include <sys/syscall.h>
  21
  22
  23 int
  24 prlimit (__pid_t pid, enum __rlimit_resource resource,
  25          const struct rlimit *new_rlimit, struct rlimit *old_rlimit)
  26 {
  27   struct rlimit64 new_rlimit64_mem;
  28   struct rlimit64 *new_rlimit64 = NULL;
  29   struct rlimit64 old_rlimit64_mem;
  30   struct rlimit64 *old_rlimit64 = (old_rlimit != NULL
  31                                    ? &old_rlimit64_mem : NULL);
  32
  33   if (new_rlimit != NULL)
  34     {
  35       if (new_rlimit->rlim_cur == RLIM_INFINITY)
  36         new_rlimit64_mem.rlim_cur = RLIM64_INFINITY;
  37       else
  38         new_rlimit64_mem.rlim_cur = new_rlimit->rlim_cur;
  39       if (new_rlimit->rlim_max == RLIM_INFINITY)
  40         new_rlimit64_mem.rlim_max = RLIM64_INFINITY;
  41       else
  42         new_rlimit64_mem.rlim_max = new_rlimit->rlim_max;
  43       new_rlimit64 = &new_rlimit64_mem;
  44     }
  45
  46   int res = INLINE_SYSCALL (prlimit64, 4, pid, resource, new_rlimit64,
  47                             old_rlimit64);
  48
  49   if (res == 0 && old_rlimit != NULL)
  50     {
  51       /* The prlimit64 syscall is ill-designed for 32-bit machines.
  52          We have to provide a 32-bit variant since otherwise the LFS
  53          system would not work.  The infinity value can be translated,
  54          but otherwise what shall we do if the syscall succeeds but the
  55          old values do not fit into a rlimit structure?  We cannot return
  56          an error because the operation itself worked.  Best is perhaps
  57          to return RLIM_INFINITY.  */
  58       old_rlimit->rlim_cur = old_rlimit64_mem.rlim_cur;
  59       if (old_rlimit->rlim_cur != old_rlimit64_mem.rlim_cur)
  60         {
  61           if ((new_rlimit == NULL)
  62               && (old_rlimit64_mem.rlim_cur != RLIM64_INFINITY))
  63             return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
  64           old_rlimit->rlim_cur = RLIM_INFINITY;
  65         }
  66       old_rlimit->rlim_max = old_rlimit64_mem.rlim_max;
  67       if (old_rlimit->rlim_max != old_rlimit64_mem.rlim_max)
  68         {
  69           if ((new_rlimit == NULL)
  70               && (old_rlimit64_mem.rlim_max != RLIM64_INFINITY))
  71             return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
  72           old_rlimit->rlim_max = RLIM_INFINITY;
  73         }
  74     }
  75
  76   return res;
  77 }