contrib/bind-9.2.4rc7/lib/isc/unix/resource.c

   1 /*
   2  * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000, 2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
  10  * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
  11  * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
  12  * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  13  * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
  14  * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  15  * PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 /* $Id: resource.c,v 1.11.2.1 2004/03/09 06:12:11 marka Exp $ */
  19
  20 #include <config.h>
  21
  22 #include <sys/types.h>
  23 #include <sys/time.h>   /* Required on some systems for <sys/resource.h>. */
  24 #include <sys/resource.h>
  25
  26 #include <isc/platform.h>
  27 #include <isc/resource.h>
  28 #include <isc/result.h>
  29 #include <isc/util.h>
  30
  31 #include "errno2result.h"
  32
  33 static isc_result_t
  34 resource2rlim(isc_resource_t resource, int *rlim_resource) {
  35         isc_result_t result = ISC_R_SUCCESS;
  36
  37         switch (resource) {
  38         case isc_resource_coresize:
  39                 *rlim_resource = RLIMIT_CORE;
  40                 break;
  41         case isc_resource_cputime:
  42                 *rlim_resource = RLIMIT_CPU;
  43                 break;
  44         case isc_resource_datasize:
  45                 *rlim_resource = RLIMIT_DATA;
  46                 break;
  47         case isc_resource_filesize:
  48                 *rlim_resource = RLIMIT_FSIZE;
  49                 break;
  50         case isc_resource_lockedmemory:
  51 #ifdef RLIMIT_MEMLOCK
  52                 *rlim_resource = RLIMIT_MEMLOCK;
  53 #else
  54                 result = ISC_R_NOTIMPLEMENTED;
  55 #endif
  56                 break;
  57         case isc_resource_openfiles:
  58 #ifdef RLIMIT_NOFILE
  59                 *rlim_resource = RLIMIT_NOFILE;
  60 #else
  61                 result = ISC_R_NOTIMPLEMENTED;
  62 #endif
  63                 break;
  64         case isc_resource_processes:
  65 #ifdef RLIMIT_NPROC
  66                 *rlim_resource = RLIMIT_NPROC;
  67 #else
  68                 result = ISC_R_NOTIMPLEMENTED;
  69 #endif
  70                 break;
  71         case isc_resource_residentsize:
  72 #ifdef RLIMIT_RSS
  73                 *rlim_resource = RLIMIT_RSS;
  74 #else
  75                 result = ISC_R_NOTIMPLEMENTED;
  76 #endif
  77                 break;
  78         case isc_resource_stacksize:
  79                 *rlim_resource = RLIMIT_STACK;
  80                 break;
  81         default:
  82                 /*
  83                  * This test is not very robust if isc_resource_t
  84                  * changes, but generates a clear assertion message.
  85                  */
  86                 REQUIRE(resource >= isc_resource_coresize &&
  87                         resource <= isc_resource_stacksize);
  88
  89                 result = ISC_R_RANGE;
  90                 break;
  91         }
  92
  93         return (result);
  94 }
  95
  96 isc_result_t
  97 isc_resource_setlimit(isc_resource_t resource, isc_resourcevalue_t value) {
  98         struct rlimit rl;
  99         ISC_PLATFORM_RLIMITTYPE rlim_value;
 100         int unixresult;
 101         int unixresource;
 102         isc_result_t result;
 103
 104         result = resource2rlim(resource, &unixresource);
 105         if (result != ISC_R_SUCCESS)
 106                 return (result);
 107
 108         if (value == ISC_RESOURCE_UNLIMITED)
 109                 rlim_value = RLIM_INFINITY;
 110
 111         else {
 112                 /*
 113                  * isc_resourcevalue_t was chosen as an unsigned 64 bit
 114                  * integer so that it could contain the maximum range of
 115                  * reasonable values.  Unfortunately, this exceeds the typical
 116                  * range on Unix systems.  Ensure the range of
 117                  * ISC_PLATFORM_RLIMITTYPE is not overflowed.
 118                  */
 119                 isc_resourcevalue_t rlim_max;
 120                 isc_boolean_t rlim_t_is_signed =
 121                         ISC_TF(((double)(ISC_PLATFORM_RLIMITTYPE)-1) < 0);
 122
 123                 if (rlim_t_is_signed)
 124                         rlim_max = ~((ISC_PLATFORM_RLIMITTYPE)1 <<
 125                                      (sizeof(ISC_PLATFORM_RLIMITTYPE) * 8 - 1));
 126                 else
 127                         rlim_max = (ISC_PLATFORM_RLIMITTYPE)-1;
 128
 129                 if (value > rlim_max)
 130                         value = rlim_max;
 131
 132                 rlim_value = value;
 133         }
 134
 135         /*
 136          * The BIND 8 documentation reports:
 137          *
 138          *      Note: on some operating systems the server cannot set an
 139          *      unlimited value and cannot determine the maximum number of
 140          *      open files the kernel can support. On such systems, choosing
 141          *      unlimited will cause the server to use the larger of the
 142          *      rlim_max for RLIMIT_NOFILE and the value returned by
 143          *      sysconf(_SC_OPEN_MAX). If the actual kernel limit is larger
 144          *      than this value, use limit files to specify the limit
 145          *      explicitly.
 146          *
 147          * The CHANGES for 8.1.2-T3A also mention:
 148          *
 149          *      352. [bug] Because of problems with setting an infinite
 150          *      rlim_max for RLIMIT_NOFILE on some systems, previous versions
 151          *      of the server implemented "limit files unlimited" by setting
 152          *      the limit to the value returned by sysconf(_SC_OPEN_MAX).  The
 153          *      server will now use RLIM_INFINITY on systems which allow it.
 154          *
 155          * At some point the BIND 8 server stopped using SC_OPEN_MAX for this
 156          * purpose at all, but it isn't clear to me when or why, as my access
 157          * to the CVS archive is limited at the time of this writing.  What
 158          * BIND 8 *does* do is to set RLIMIT_NOFILE to either RLIMIT_INFINITY
 159          * on a half dozen operating systems or to FD_SETSIZE on the rest,
 160          * the latter of which is probably fewer than the real limit.  (Note
 161          * that libisc's socket module will have problems with any fd over
 162          * FD_SETSIZE.  This should be fixed in the socket module, not a
 163          * limitation here.  BIND 8's eventlib also has a problem, making
 164          * its RLIMIT_INFINITY setting useless, because it closes and ignores
 165          * any fd over FD_SETSIZE.)
 166          *
 167          * More troubling is the reference to some operating systems not being
 168          * able to set an unlimited value for the number of open files.  I'd
 169          * hate to put in code that is really only there to support archaic
 170          * systems that the rest of libisc won't work on anyway.  So what this
 171          * extremely verbose comment is here to say is the following:
 172          *
 173          *   I'm aware there might be an issue with not limiting the value
 174          *   for RLIMIT_NOFILE on some systems, but since I don't know yet
 175          *   what those systems are and what the best workaround is (use
 176          *   sysconf()?  rlim_max from getrlimit()?  FD_SETSIZE?) so nothing
 177          *   is currently being done to clamp the value for open files.
 178          */
 179
 180         rl.rlim_cur = rl.rlim_max = rlim_value;
 181         unixresult = setrlimit(unixresource, &rl);
 182
 183         if (unixresult == 0)
 184                 return (ISC_R_SUCCESS);
 185         else
 186                 return (isc__errno2result(errno));
 187 }
 188
 189 isc_result_t
 190 isc_resource_getlimit(isc_resource_t resource, isc_resourcevalue_t *value) {
 191         int unixresult;
 192         int unixresource;
 193         struct rlimit rl;
 194         isc_result_t result;
 195
 196         result = resource2rlim(resource, &unixresource);
 197         if (result == ISC_R_SUCCESS) {
 198                 unixresult = getrlimit(unixresource, &rl);
 199                 INSIST(unixresult == 0);
 200                 *value = rl.rlim_max;
 201         }
 202
 203         return (result);
 204 }