sysdeps/unix/sysv/linux/prlimit.c

   1 /* Copyright (C) 2010-2016 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 #ifdef __NR_prlimit64
  24 int
  25 prlimit (__pid_t pid, enum __rlimit_resource resource,
  26          const struct rlimit *new_rlimit, struct rlimit *old_rlimit)
  27 {
  28   struct rlimit64 new_rlimit64_mem;
  29   struct rlimit64 *new_rlimit64 = NULL;
  30   struct rlimit64 old_rlimit64_mem;
  31   struct rlimit64 *old_rlimit64 = (old_rlimit != NULL
  32                                    ? &old_rlimit64_mem : NULL);
  33
  34   if (new_rlimit != NULL)
  35     {
  36       if (new_rlimit->rlim_cur == RLIM_INFINITY)
  37         new_rlimit64_mem.rlim_cur = RLIM64_INFINITY;
  38       else
  39         new_rlimit64_mem.rlim_cur = new_rlimit->rlim_cur;
  40       if (new_rlimit->rlim_max == RLIM_INFINITY)
  41         new_rlimit64_mem.rlim_max = RLIM64_INFINITY;
  42       else
  43         new_rlimit64_mem.rlim_max = new_rlimit->rlim_max;
  44       new_rlimit64 = &new_rlimit64_mem;
  45     }
  46
  47   int res = INLINE_SYSCALL (prlimit64, 4, pid, resource, new_rlimit64,
  48                             old_rlimit64);
  49
  50   if (res == 0 && old_rlimit != NULL)
  51     {
  52       /* The prlimit64 syscall is ill-designed for 32-bit machines.
  53          We have to provide a 32-bit variant since otherwise the LFS
  54          system would not work.  But what shall we do if the syscall
  55          succeeds but the old values do not fit into a rlimit
  56          structure?  We cannot return an error because the operation
  57          itself worked.  Best is perhaps 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             return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
  63           old_rlimit->rlim_cur = RLIM_INFINITY;
  64         }
  65       old_rlimit->rlim_max = old_rlimit64_mem.rlim_max;
  66       if (old_rlimit->rlim_max != old_rlimit64_mem.rlim_max)
  67         {
  68           if (new_rlimit == NULL)
  69             return INLINE_SYSCALL_ERROR_RETURN_VALUE (EOVERFLOW);
  70           old_rlimit->rlim_max = RLIM_INFINITY;
  71         }
  72     }
  73
  74   return res;
  75 }
  76 #else
  77 int
  78 prlimit (__pid_t pid, enum __rlimit_resource resource,
  79          const struct rlimit *new_rlimit, struct rlimit *old_rlimit)
  80 {
  81   return INLINE_SYSCALL_ERROR_RETURN_VALUE (ENOSYS);
  82 }
  83 stub_warning (prlimit)
  84 #endif