sysdeps/unix/sysv/linux/prlimit.c

   1 /* Copyright (C) 2010-2017 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.  But what shall we do if the syscall
  54          succeeds but the old values do not fit into a rlimit
  55          structure?  We cannot return an error because the operation
  56          itself worked.  Best is perhaps to return RLIM_INFINITY.  */
  57       old_rlimit->rlim_cur = old_rlimit64_mem.rlim_cur;
  58       if (old_rlimit->rlim_cur != old_rlimit64_mem.rlim_cur)
  59         {
  60           if (new_rlimit == NULL)
  61             return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
  62           old_rlimit->rlim_cur = RLIM_INFINITY;
  63         }
  64       old_rlimit->rlim_max = old_rlimit64_mem.rlim_max;
  65       if (old_rlimit->rlim_max != old_rlimit64_mem.rlim_max)
  66         {
  67           if (new_rlimit == NULL)
  68             return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
  69           old_rlimit->rlim_max = RLIM_INFINITY;
  70         }
  71     }
  72
  73   return res;
  74 }