sysdeps/unix/sysv/linux/prlimit.c

   1 /* Copyright (C) 2010-2015 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   INTERNAL_SYSCALL_DECL (err);
  48   int res = INTERNAL_SYSCALL (prlimit64, err, 4, pid, resource,
  49                               new_rlimit64, old_rlimit64);
  50
  51   if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (res, err)))
  52     return INLINE_SYSCALL_ERROR_RETURN (-INTERNAL_SYSCALL_ERRNO (res,
  53                                                                  err),
  54                                         int, -1);
  55   else if (old_rlimit != NULL)
  56     {
  57       /* The prlimit64 syscall is ill-designed for 32-bit machines.
  58          We have to provide a 32-bit variant since otherwise the LFS
  59          system would not work.  But what shall we do if the syscall
  60          succeeds but the old values do not fit into a rlimit
  61          structure?  We cannot return an error because the operation
  62          itself worked.  Best is perhaps to return RLIM_INFINITY.  */
  63       old_rlimit->rlim_cur = old_rlimit64_mem.rlim_cur;
  64       if (old_rlimit->rlim_cur != old_rlimit64_mem.rlim_cur)
  65         {
  66           if (new_rlimit == NULL)
  67             return INLINE_SYSCALL_ERROR_RETURN (-EOVERFLOW, int, -1);
  68           old_rlimit->rlim_cur = RLIM_INFINITY;
  69         }
  70       old_rlimit->rlim_max = old_rlimit64_mem.rlim_max;
  71       if (old_rlimit->rlim_max != old_rlimit64_mem.rlim_max)
  72         {
  73           if (new_rlimit == NULL)
  74             return INLINE_SYSCALL_ERROR_RETURN (-EOVERFLOW, int, -1);
  75           old_rlimit->rlim_max = RLIM_INFINITY;
  76         }
  77     }
  78
  79   return res;
  80 }
  81 #else
  82 int
  83 prlimit (__pid_t pid, enum __rlimit_resource resource,
  84          const struct rlimit *new_rlimit, struct rlimit *old_rlimit)
  85 {
  86   return INLINE_SYSCALL_ERROR_RETURN (-ENOSYS, int, -1);
  87 }
  88 stub_warning (prlimit)
  89 #endif