lib/getloadavg.c

   1 /* Get the system load averages.
   2
   3    Copyright (C) 1985-1989, 1991-1995, 1997, 1999-2000, 2003-2011 Free Software
   4    Foundation, Inc.
   5
   6    NOTE: The canonical source of this file is maintained with gnulib.
   7    Bugs can be reported to bug-gnulib@gnu.org.
   8
   9    This program is free software: you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 /* Compile-time symbols that this file uses:
  23
  24    HAVE_PSTAT_GETDYNAMIC        Define this if your system has the
  25                                 pstat_getdynamic function.  I think it
  26                                 is unique to HPUX9.  The best way to get the
  27                                 definition is through the AC_FUNC_GETLOADAVG
  28                                 macro that comes with autoconf 2.13 or newer.
  29                                 If that isn't an option, then just put
  30                                 AC_CHECK_FUNCS(pstat_getdynamic) in your
  31                                 configure.in file.
  32    HAVE_LIBPERFSTAT Define this if your system has the
  33                                 perfstat_cpu_total function in libperfstat (AIX).
  34    FIXUP_KERNEL_SYMBOL_ADDR()   Adjust address in returned struct nlist.
  35    KERNEL_FILE                  Name of the kernel file to nlist.
  36    LDAV_CVT()                   Scale the load average from the kernel.
  37                                 Returns a double.
  38    LDAV_SYMBOL                  Name of kernel symbol giving load average.
  39    LOAD_AVE_TYPE                Type of the load average array in the kernel.
  40                                 Must be defined unless one of
  41                                 apollo, DGUX, NeXT, or UMAX is defined;
  42                                 or we have libkstat;
  43                                 otherwise, no load average is available.
  44    HAVE_NLIST_H                 nlist.h is available.  NLIST_STRUCT defaults
  45                                 to this.
  46    NLIST_STRUCT                 Include nlist.h, not a.out.h.
  47    N_NAME_POINTER               The nlist n_name element is a pointer,
  48                                 not an array.
  49    HAVE_STRUCT_NLIST_N_UN_N_NAME `n_un.n_name' is member of `struct nlist'.
  50    LINUX_LDAV_FILE              [__linux__, __CYGWIN__]: File containing
  51                                 load averages.
  52
  53    Specific system predefines this file uses, aside from setting
  54    default values if not emacs:
  55
  56    apollo
  57    BSD                          Real BSD, not just BSD-like.
  58    convex
  59    DGUX
  60    eunice                       UNIX emulator under VMS.
  61    hpux
  62    __MSDOS__                    No-op for MSDOS.
  63    NeXT
  64    sgi
  65    sequent                      Sequent Dynix 3.x.x (BSD)
  66    _SEQUENT_                    Sequent DYNIX/ptx 1.x.x (SYSV)
  67    sony_news                    NEWS-OS (works at least for 4.1C)
  68    UMAX
  69    UMAX4_3
  70    VMS
  71    WINDOWS32                    No-op for Windows95/NT.
  72    __linux__                    Linux: assumes /proc file system mounted.
  73                                 Support from Michael K. Johnson.
  74    __CYGWIN__                   Cygwin emulates linux /proc/loadavg.
  75    __NetBSD__                   NetBSD: assumes /kern file system mounted.
  76
  77    In addition, to avoid nesting many #ifdefs, we internally set
  78    LDAV_DONE to indicate that the load average has been computed.
  79
  80    We also #define LDAV_PRIVILEGED if a program will require
  81    special installation to be able to call getloadavg.  */
  82
  83 /* "configure" defines CONFIGURING_GETLOADAVG to sidestep problems
  84    with partially-configured source directories.  */
  85
  86 #ifndef CONFIGURING_GETLOADAVG
  87 # include <config.h>
  88 # include <stdbool.h>
  89 #endif
  90
  91 /* Specification.  */
  92 #include <stdlib.h>
  93
  94 #include <errno.h>
  95 #include <stdio.h>
  96
  97 # include <sys/types.h>
  98
  99 /* Both the Emacs and non-Emacs sections want this.  Some
 100    configuration files' definitions for the LOAD_AVE_CVT macro (like
 101    sparc.h's) use macros like FSCALE, defined here.  */
 102 # if defined (unix) || defined (__unix)
 103 #  include <sys/param.h>
 104 # endif
 105
 106 # include "intprops.h"
 107
 108 /* The existing Emacs configuration files define a macro called
 109    LOAD_AVE_CVT, which accepts a value of type LOAD_AVE_TYPE, and
 110    returns the load average multiplied by 100.  What we actually want
 111    is a macro called LDAV_CVT, which returns the load average as an
 112    unmultiplied double.
 113
 114    For backwards compatibility, we'll define LDAV_CVT in terms of
 115    LOAD_AVE_CVT, but future machine config files should just define
 116    LDAV_CVT directly.  */
 117
 118 # if !defined (LDAV_CVT) && defined (LOAD_AVE_CVT)
 119 #  define LDAV_CVT(n) (LOAD_AVE_CVT (n) / 100.0)
 120 # endif
 121
 122 # if !defined (BSD) && defined (ultrix)
 123 /* Ultrix behaves like BSD on Vaxen.  */
 124 #  define BSD
 125 # endif
 126
 127 # ifdef NeXT
 128 /* NeXT in the 2.{0,1,2} releases defines BSD in <sys/param.h>, which
 129    conflicts with the definition understood in this file, that this
 130    really is BSD. */
 131 #  undef BSD
 132
 133 /* NeXT defines FSCALE in <sys/param.h>.  However, we take FSCALE being
 134    defined to mean that the nlist method should be used, which is not true.  */
 135 #  undef FSCALE
 136 # endif
 137
 138 /* Same issues as for NeXT apply to the HURD-based GNU system.  */
 139 # ifdef __GNU__
 140 #  undef BSD
 141 #  undef FSCALE
 142 # endif /* __GNU__ */
 143
 144 /* Set values that are different from the defaults, which are
 145    set a little farther down with #ifndef.  */
 146
 147
 148 /* Some shorthands.  */
 149
 150 # if defined (HPUX) && !defined (hpux)
 151 #  define hpux
 152 # endif
 153
 154 # if defined (__hpux) && !defined (hpux)
 155 #  define hpux
 156 # endif
 157
 158 # if defined (__sun) && !defined (sun)
 159 #  define sun
 160 # endif
 161
 162 # if defined (hp300) && !defined (hpux)
 163 #  define MORE_BSD
 164 # endif
 165
 166 # if defined (ultrix) && defined (mips)
 167 #  define decstation
 168 # endif
 169
 170 # if defined (__SVR4) && !defined (SVR4)
 171 #  define SVR4
 172 # endif
 173
 174 # if (defined (sun) && defined (SVR4)) || defined (SOLARIS2)
 175 #  define SUNOS_5
 176 # endif
 177
 178 # if defined (__osf__) && (defined (__alpha) || defined (__alpha__))
 179 #  define OSF_ALPHA
 180 #  include <sys/mbuf.h>
 181 #  include <sys/socket.h>
 182 #  include <net/route.h>
 183 #  include <sys/table.h>
 184 /* Tru64 4.0D's table.h redefines sys */
 185 #  undef sys
 186 # endif
 187
 188 # if defined (__osf__) && (defined (mips) || defined (__mips__))
 189 #  define OSF_MIPS
 190 #  include <sys/table.h>
 191 # endif
 192
 193 /* UTek's /bin/cc on the 4300 has no architecture specific cpp define by
 194    default, but _MACH_IND_SYS_TYPES is defined in <sys/types.h>.  Combine
 195    that with a couple of other things and we'll have a unique match.  */
 196 # if !defined (tek4300) && defined (unix) && defined (m68k) && defined (mc68000) && defined (mc68020) && defined (_MACH_IND_SYS_TYPES)
 197 #  define tek4300                       /* Define by emacs, but not by other users.  */
 198 # endif
 199
 200
 201 /* VAX C can't handle multi-line #ifs, or lines longer than 256 chars.  */
 202 # ifndef LOAD_AVE_TYPE
 203
 204 #  ifdef MORE_BSD
 205 #   define LOAD_AVE_TYPE long
 206 #  endif
 207
 208 #  ifdef sun
 209 #   define LOAD_AVE_TYPE long
 210 #  endif
 211
 212 #  ifdef decstation
 213 #   define LOAD_AVE_TYPE long
 214 #  endif
 215
 216 #  ifdef _SEQUENT_
 217 #   define LOAD_AVE_TYPE long
 218 #  endif
 219
 220 #  ifdef sgi
 221 #   define LOAD_AVE_TYPE long
 222 #  endif
 223
 224 #  ifdef SVR4
 225 #   define LOAD_AVE_TYPE long
 226 #  endif
 227
 228 #  ifdef sony_news
 229 #   define LOAD_AVE_TYPE long
 230 #  endif
 231
 232 #  ifdef sequent
 233 #   define LOAD_AVE_TYPE long
 234 #  endif
 235
 236 #  ifdef OSF_ALPHA
 237 #   define LOAD_AVE_TYPE long
 238 #  endif
 239
 240 #  if defined (ardent) && defined (titan)
 241 #   define LOAD_AVE_TYPE long
 242 #  endif
 243
 244 #  ifdef tek4300
 245 #   define LOAD_AVE_TYPE long
 246 #  endif
 247
 248 #  if defined (alliant) && defined (i860) /* Alliant FX/2800 */
 249 #   define LOAD_AVE_TYPE long
 250 #  endif
 251
 252 #  if defined _AIX && ! defined HAVE_LIBPERFSTAT
 253 #   define LOAD_AVE_TYPE long
 254 #  endif
 255
 256 #  ifdef convex
 257 #   define LOAD_AVE_TYPE double
 258 #   ifndef LDAV_CVT
 259 #    define LDAV_CVT(n) (n)
 260 #   endif
 261 #  endif
 262
 263 # endif /* No LOAD_AVE_TYPE.  */
 264
 265 # ifdef OSF_ALPHA
 266 /* <sys/param.h> defines an incorrect value for FSCALE on Alpha OSF/1,
 267    according to ghazi@noc.rutgers.edu.  */
 268 #  undef FSCALE
 269 #  define FSCALE 1024.0
 270 # endif
 271
 272 # if defined (alliant) && defined (i860) /* Alliant FX/2800 */
 273 /* <sys/param.h> defines an incorrect value for FSCALE on an
 274    Alliant FX/2800 Concentrix 2.2, according to ghazi@noc.rutgers.edu.  */
 275 #  undef FSCALE
 276 #  define FSCALE 100.0
 277 # endif
 278
 279
 280 # ifndef FSCALE
 281
 282 /* SunOS and some others define FSCALE in sys/param.h.  */
 283
 284 #  ifdef MORE_BSD
 285 #   define FSCALE 2048.0
 286 #  endif
 287
 288 #  if defined (MIPS) || defined (SVR4) || defined (decstation)
 289 #   define FSCALE 256
 290 #  endif
 291
 292 #  if defined (sgi) || defined (sequent)
 293 /* Sometimes both MIPS and sgi are defined, so FSCALE was just defined
 294    above under #ifdef MIPS.  But we want the sgi value.  */
 295 #   undef FSCALE
 296 #   define FSCALE 1000.0
 297 #  endif
 298
 299 #  if defined (ardent) && defined (titan)
 300 #   define FSCALE 65536.0
 301 #  endif
 302
 303 #  ifdef tek4300
 304 #   define FSCALE 100.0
 305 #  endif
 306
 307 #  if defined _AIX && !defined HAVE_LIBPERFSTAT
 308 #   define FSCALE 65536.0
 309 #  endif
 310
 311 # endif /* Not FSCALE.  */
 312
 313 # if !defined (LDAV_CVT) && defined (FSCALE)
 314 #  define LDAV_CVT(n) (((double) (n)) / FSCALE)
 315 # endif
 316
 317 # ifndef NLIST_STRUCT
 318 #  if HAVE_NLIST_H
 319 #   define NLIST_STRUCT
 320 #  endif
 321 # endif
 322
 323 # if defined (sgi) || (defined (mips) && !defined (BSD))
 324 #  define FIXUP_KERNEL_SYMBOL_ADDR(nl) ((nl)[0].n_value &= ~(1 << 31))
 325 # endif
 326
 327
 328 # if !defined (KERNEL_FILE) && defined (sequent)
 329 #  define KERNEL_FILE "/dynix"
 330 # endif
 331
 332 # if !defined (KERNEL_FILE) && defined (hpux)
 333 #  define KERNEL_FILE "/hp-ux"
 334 # endif
 335
 336 # if !defined (KERNEL_FILE) && (defined (_SEQUENT_) || defined (MIPS) || defined (SVR4) || defined (ISC) || defined (sgi) || (defined (ardent) && defined (titan)))
 337 #  define KERNEL_FILE "/unix"
 338 # endif
 339
 340
 341 # if !defined (LDAV_SYMBOL) && defined (alliant)
 342 #  define LDAV_SYMBOL "_Loadavg"
 343 # endif
 344
 345 # if !defined (LDAV_SYMBOL) && ((defined (hpux) && !defined (hp9000s300)) || defined (_SEQUENT_) || defined (SVR4) || defined (ISC) || defined (sgi) || (defined (ardent) && defined (titan)) || (defined (_AIX) && !defined(HAVE_LIBPERFSTAT)))
 346 #  define LDAV_SYMBOL "avenrun"
 347 # endif
 348
 349 # include <unistd.h>
 350
 351 /* LOAD_AVE_TYPE should only get defined if we're going to use the
 352    nlist method.  */
 353 # if !defined (LOAD_AVE_TYPE) && (defined (BSD) || defined (LDAV_CVT) || defined (KERNEL_FILE) || defined (LDAV_SYMBOL))
 354 #  define LOAD_AVE_TYPE double
 355 # endif
 356
 357 # ifdef LOAD_AVE_TYPE
 358
 359 #  ifndef __VMS
 360 #   ifndef __linux__
 361 #    ifndef NLIST_STRUCT
 362 #     include <a.out.h>
 363 #    else /* NLIST_STRUCT */
 364 #     include <nlist.h>
 365 #    endif /* NLIST_STRUCT */
 366
 367 #    ifdef SUNOS_5
 368 #     include <kvm.h>
 369 #     include <kstat.h>
 370 #    endif
 371
 372 #    if defined (hpux) && defined (HAVE_PSTAT_GETDYNAMIC)
 373 #     include <sys/pstat.h>
 374 #    endif
 375
 376 #    ifndef KERNEL_FILE
 377 #     define KERNEL_FILE "/vmunix"
 378 #    endif /* KERNEL_FILE */
 379
 380 #    ifndef LDAV_SYMBOL
 381 #     define LDAV_SYMBOL "_avenrun"
 382 #    endif /* LDAV_SYMBOL */
 383 #   endif /* __linux__ */
 384
 385 #  else /* __VMS */
 386
 387 #   ifndef eunice
 388 #    include <iodef.h>
 389 #    include <descrip.h>
 390 #   else /* eunice */
 391 #    include <vms/iodef.h>
 392 #   endif /* eunice */
 393 #  endif /* __VMS */
 394
 395 #  ifndef LDAV_CVT
 396 #   define LDAV_CVT(n) ((double) (n))
 397 #  endif /* !LDAV_CVT */
 398
 399 # endif /* LOAD_AVE_TYPE */
 400
 401 # if defined HAVE_LIBPERFSTAT
 402 #  include <sys/protosw.h>
 403 #  include <libperfstat.h>
 404 #  include <sys/proc.h>
 405 #  ifndef SBITS
 406 #   define SBITS 16
 407 #  endif
 408 # endif
 409
 410 # if defined (__GNU__) && !defined (NeXT)
 411 /* Note that NeXT Openstep defines __GNU__ even though it should not.  */
 412 /* GNU system acts much like NeXT, for load average purposes,
 413    but not exactly.  */
 414 #  define NeXT
 415 #  define host_self mach_host_self
 416 # endif
 417
 418 # ifdef NeXT
 419 #  ifdef HAVE_MACH_MACH_H
 420 #   include <mach/mach.h>
 421 #  else
 422 #   include <mach.h>
 423 #  endif
 424 # endif /* NeXT */
 425
 426 # ifdef sgi
 427 #  include <sys/sysmp.h>
 428 # endif /* sgi */
 429
 430 # ifdef UMAX
 431 #  include <signal.h>
 432 #  include <sys/time.h>
 433 #  include <sys/wait.h>
 434 #  include <sys/syscall.h>
 435
 436 #  ifdef UMAX_43
 437 #   include <machine/cpu.h>
 438 #   include <inq_stats/statistics.h>
 439 #   include <inq_stats/sysstats.h>
 440 #   include <inq_stats/cpustats.h>
 441 #   include <inq_stats/procstats.h>
 442 #  else /* Not UMAX_43.  */
 443 #   include <sys/sysdefs.h>
 444 #   include <sys/statistics.h>
 445 #   include <sys/sysstats.h>
 446 #   include <sys/cpudefs.h>
 447 #   include <sys/cpustats.h>
 448 #   include <sys/procstats.h>
 449 #  endif /* Not UMAX_43.  */
 450 # endif /* UMAX */
 451
 452 # ifdef DGUX
 453 #  include <sys/dg_sys_info.h>
 454 # endif
 455
 456 # if (defined __linux__ || defined __CYGWIN__ || defined SUNOS_5        \
 457       || (defined LOAD_AVE_TYPE && ! defined __VMS))
 458 #  include <fcntl.h>
 459 # endif
 460 \f
 461 /* Avoid static vars inside a function since in HPUX they dump as pure.  */
 462
 463 # ifdef NeXT
 464 static processor_set_t default_set;
 465 static bool getloadavg_initialized;
 466 # endif /* NeXT */
 467
 468 # ifdef UMAX
 469 static unsigned int cpus = 0;
 470 static unsigned int samples;
 471 # endif /* UMAX */
 472
 473 # ifdef DGUX
 474 static struct dg_sys_info_load_info load_info;  /* what-a-mouthful! */
 475 # endif /* DGUX */
 476
 477 # if !defined (HAVE_LIBKSTAT) && defined (LOAD_AVE_TYPE)
 478 /* File descriptor open to /dev/kmem or VMS load ave driver.  */
 479 static int channel;
 480 /* True if channel is valid.  */
 481 static bool getloadavg_initialized;
 482 /* Offset in kmem to seek to read load average, or 0 means invalid.  */
 483 static long offset;
 484
 485 #  if ! defined __VMS && ! defined sgi && ! defined __linux__
 486 static struct nlist name_list[2];
 487 #  endif
 488
 489 #  ifdef SUNOS_5
 490 static kvm_t *kd;
 491 #  endif /* SUNOS_5 */
 492
 493 # endif /* LOAD_AVE_TYPE && !HAVE_LIBKSTAT */
 494 \f
 495 /* Put the 1 minute, 5 minute and 15 minute load averages
 496    into the first NELEM elements of LOADAVG.
 497    Return the number written (never more than 3, but may be less than NELEM),
 498    or -1 (setting errno) if an error occurred.  */
 499
 500 int
 501 getloadavg (double loadavg[], int nelem)
 502 {
 503   int elem = 0;                 /* Return value.  */
 504
 505 # ifdef NO_GET_LOAD_AVG
 506 #  define LDAV_DONE
 507   errno = ENOSYS;
 508   elem = -1;
 509 # endif
 510
 511 # if !defined (LDAV_DONE) && defined (HAVE_LIBKSTAT)       /* Solaris <= 2.6 */
 512 /* Use libkstat because we don't have to be root.  */
 513 #  define LDAV_DONE
 514   kstat_ctl_t *kc;
 515   kstat_t *ksp;
 516   kstat_named_t *kn;
 517   int saved_errno;
 518
 519   kc = kstat_open ();
 520   if (kc == 0)
 521     return -1;
 522   ksp = kstat_lookup (kc, "unix", 0, "system_misc");
 523   if (ksp == 0)
 524     return -1;
 525   if (kstat_read (kc, ksp, 0) == -1)
 526     return -1;
 527
 528
 529   kn = kstat_data_lookup (ksp, "avenrun_1min");
 530   if (kn == 0)
 531     {
 532       /* Return -1 if no load average information is available.  */
 533       nelem = 0;
 534       elem = -1;
 535     }
 536
 537   if (nelem >= 1)
 538     loadavg[elem++] = (double) kn->value.ul / FSCALE;
 539
 540   if (nelem >= 2)
 541     {
 542       kn = kstat_data_lookup (ksp, "avenrun_5min");
 543       if (kn != 0)
 544         {
 545           loadavg[elem++] = (double) kn->value.ul / FSCALE;
 546
 547           if (nelem >= 3)
 548             {
 549               kn = kstat_data_lookup (ksp, "avenrun_15min");
 550               if (kn != 0)
 551                 loadavg[elem++] = (double) kn->value.ul / FSCALE;
 552             }
 553         }
 554     }
 555
 556   saved_errno = errno;
 557   kstat_close (kc);
 558   errno = saved_errno;
 559 # endif /* HAVE_LIBKSTAT */
 560
 561 # if !defined (LDAV_DONE) && defined (hpux) && defined (HAVE_PSTAT_GETDYNAMIC)
 562                                                            /* HP-UX */
 563 /* Use pstat_getdynamic() because we don't have to be root.  */
 564 #  define LDAV_DONE
 565 #  undef LOAD_AVE_TYPE
 566
 567   struct pst_dynamic dyn_info;
 568   if (pstat_getdynamic (&dyn_info, sizeof (dyn_info), 0, 0) < 0)
 569     return -1;
 570   if (nelem > 0)
 571     loadavg[elem++] = dyn_info.psd_avg_1_min;
 572   if (nelem > 1)
 573     loadavg[elem++] = dyn_info.psd_avg_5_min;
 574   if (nelem > 2)
 575     loadavg[elem++] = dyn_info.psd_avg_15_min;
 576
 577 # endif /* hpux && HAVE_PSTAT_GETDYNAMIC */
 578
 579 # if ! defined LDAV_DONE && defined HAVE_LIBPERFSTAT       /* AIX */
 580 #  define LDAV_DONE
 581 #  undef LOAD_AVE_TYPE
 582 /* Use perfstat_cpu_total because we don't have to be root. */
 583   {
 584     perfstat_cpu_total_t cpu_stats;
 585     int result = perfstat_cpu_total (NULL, &cpu_stats, sizeof cpu_stats, 1);
 586     if (result == -1)
 587       return result;
 588     loadavg[0] = cpu_stats.loadavg[0] / (double)(1 << SBITS);
 589     loadavg[1] = cpu_stats.loadavg[1] / (double)(1 << SBITS);
 590     loadavg[2] = cpu_stats.loadavg[2] / (double)(1 << SBITS);
 591     elem = 3;
 592   }
 593 # endif
 594
 595 # if !defined (LDAV_DONE) && (defined (__linux__) || defined (__CYGWIN__))
 596                                               /* Linux without glibc, Cygwin */
 597 #  define LDAV_DONE
 598 #  undef LOAD_AVE_TYPE
 599
 600 #  ifndef LINUX_LDAV_FILE
 601 #   define LINUX_LDAV_FILE "/proc/loadavg"
 602 #  endif
 603
 604   char ldavgbuf[3 * (INT_STRLEN_BOUND (int) + sizeof ".00 ")];
 605   char const *ptr = ldavgbuf;
 606   int fd, count, saved_errno;
 607
 608   fd = open (LINUX_LDAV_FILE, O_RDONLY);
 609   if (fd == -1)
 610     return -1;
 611   count = read (fd, ldavgbuf, sizeof ldavgbuf - 1);
 612   saved_errno = errno;
 613   (void) close (fd);
 614   errno = saved_errno;
 615   if (count <= 0)
 616     return -1;
 617   ldavgbuf[count] = '\0';
 618
 619   for (elem = 0; elem < nelem; elem++)
 620     {
 621       double numerator = 0;
 622       double denominator = 1;
 623
 624       while (*ptr == ' ')
 625         ptr++;
 626
 627       /* Finish if this number is missing, and report an error if all
 628          were missing.  */
 629       if (! ('0' <= *ptr && *ptr <= '9'))
 630         {
 631           if (elem == 0)
 632             {
 633               errno = ENOTSUP;
 634               return -1;
 635             }
 636           break;
 637         }
 638
 639       while ('0' <= *ptr && *ptr <= '9')
 640         numerator = 10 * numerator + (*ptr++ - '0');
 641
 642       if (*ptr == '.')
 643         for (ptr++; '0' <= *ptr && *ptr <= '9'; ptr++)
 644           numerator = 10 * numerator + (*ptr - '0'), denominator *= 10;
 645
 646       loadavg[elem++] = numerator / denominator;
 647     }
 648
 649   return elem;
 650
 651 # endif /* __linux__ || __CYGWIN__ */
 652
 653 # if !defined (LDAV_DONE) && defined (__NetBSD__)          /* NetBSD < 0.9 */
 654 #  define LDAV_DONE
 655 #  undef LOAD_AVE_TYPE
 656
 657 #  ifndef NETBSD_LDAV_FILE
 658 #   define NETBSD_LDAV_FILE "/kern/loadavg"
 659 #  endif
 660
 661   unsigned long int load_ave[3], scale;
 662   int count;
 663   FILE *fp;
 664
 665   fp = fopen (NETBSD_LDAV_FILE, "r");
 666   if (fp == NULL)
 667     return -1;
 668   count = fscanf (fp, "%lu %lu %lu %lu\n",
 669                   &load_ave[0], &load_ave[1], &load_ave[2],
 670                   &scale);
 671   (void) fclose (fp);
 672   if (count != 4)
 673     {
 674       errno = ENOTSUP;
 675       return -1;
 676     }
 677
 678   for (elem = 0; elem < nelem; elem++)
 679     loadavg[elem] = (double) load_ave[elem] / (double) scale;
 680
 681   return elem;
 682
 683 # endif /* __NetBSD__ */
 684
 685 # if !defined (LDAV_DONE) && defined (NeXT)                /* NeXTStep */
 686 #  define LDAV_DONE
 687   /* The NeXT code was adapted from iscreen 3.2.  */
 688
 689   host_t host;
 690   struct processor_set_basic_info info;
 691   unsigned int info_count;
 692
 693   /* We only know how to get the 1-minute average for this system,
 694      so even if the caller asks for more than 1, we only return 1.  */
 695
 696   if (!getloadavg_initialized)
 697     {
 698       if (processor_set_default (host_self (), &default_set) == KERN_SUCCESS)
 699         getloadavg_initialized = true;
 700     }
 701
 702   if (getloadavg_initialized)
 703     {
 704       info_count = PROCESSOR_SET_BASIC_INFO_COUNT;
 705       if (processor_set_info (default_set, PROCESSOR_SET_BASIC_INFO, &host,
 706                               (processor_set_info_t) &info, &info_count)
 707           != KERN_SUCCESS)
 708         getloadavg_initialized = false;
 709       else
 710         {
 711           if (nelem > 0)
 712             loadavg[elem++] = (double) info.load_average / LOAD_SCALE;
 713         }
 714     }
 715
 716   if (!getloadavg_initialized)
 717     {
 718       errno = ENOTSUP;
 719       return -1;
 720     }
 721 # endif /* NeXT */
 722
 723 # if !defined (LDAV_DONE) && defined (UMAX)
 724 #  define LDAV_DONE
 725 /* UMAX 4.2, which runs on the Encore Multimax multiprocessor, does not
 726    have a /dev/kmem.  Information about the workings of the running kernel
 727    can be gathered with inq_stats system calls.
 728    We only know how to get the 1-minute average for this system.  */
 729
 730   struct proc_summary proc_sum_data;
 731   struct stat_descr proc_info;
 732   double load;
 733   register unsigned int i, j;
 734
 735   if (cpus == 0)
 736     {
 737       register unsigned int c, i;
 738       struct cpu_config conf;
 739       struct stat_descr desc;
 740
 741       desc.sd_next = 0;
 742       desc.sd_subsys = SUBSYS_CPU;
 743       desc.sd_type = CPUTYPE_CONFIG;
 744       desc.sd_addr = (char *) &conf;
 745       desc.sd_size = sizeof conf;
 746
 747       if (inq_stats (1, &desc))
 748         return -1;
 749
 750       c = 0;
 751       for (i = 0; i < conf.config_maxclass; ++i)
 752         {
 753           struct class_stats stats;
 754           memset (&stats, 0, sizeof stats);
 755
 756           desc.sd_type = CPUTYPE_CLASS;
 757           desc.sd_objid = i;
 758           desc.sd_addr = (char *) &stats;
 759           desc.sd_size = sizeof stats;
 760
 761           if (inq_stats (1, &desc))
 762             return -1;
 763
 764           c += stats.class_numcpus;
 765         }
 766       cpus = c;
 767       samples = cpus < 2 ? 3 : (2 * cpus / 3);
 768     }
 769
 770   proc_info.sd_next = 0;
 771   proc_info.sd_subsys = SUBSYS_PROC;
 772   proc_info.sd_type = PROCTYPE_SUMMARY;
 773   proc_info.sd_addr = (char *) &proc_sum_data;
 774   proc_info.sd_size = sizeof (struct proc_summary);
 775   proc_info.sd_sizeused = 0;
 776
 777   if (inq_stats (1, &proc_info) != 0)
 778     return -1;
 779
 780   load = proc_sum_data.ps_nrunnable;
 781   j = 0;
 782   for (i = samples - 1; i > 0; --i)
 783     {
 784       load += proc_sum_data.ps_nrun[j];
 785       if (j++ == PS_NRUNSIZE)
 786         j = 0;
 787     }
 788
 789   if (nelem > 0)
 790     loadavg[elem++] = load / samples / cpus;
 791 # endif /* UMAX */
 792
 793 # if !defined (LDAV_DONE) && defined (DGUX)
 794 #  define LDAV_DONE
 795   /* This call can return -1 for an error, but with good args
 796      it's not supposed to fail.  The first argument is for no
 797      apparent reason of type `long int *'.  */
 798   dg_sys_info ((long int *) &load_info,
 799                DG_SYS_INFO_LOAD_INFO_TYPE,
 800                DG_SYS_INFO_LOAD_VERSION_0);
 801
 802   if (nelem > 0)
 803     loadavg[elem++] = load_info.one_minute;
 804   if (nelem > 1)
 805     loadavg[elem++] = load_info.five_minute;
 806   if (nelem > 2)
 807     loadavg[elem++] = load_info.fifteen_minute;
 808 # endif /* DGUX */
 809
 810 # if !defined (LDAV_DONE) && defined (apollo)
 811 #  define LDAV_DONE
 812 /* Apollo code from lisch@mentorg.com (Ray Lischner).
 813
 814    This system call is not documented.  The load average is obtained as
 815    three long integers, for the load average over the past minute,
 816    five minutes, and fifteen minutes.  Each value is a scaled integer,
 817    with 16 bits of integer part and 16 bits of fraction part.
 818
 819    I'm not sure which operating system first supported this system call,
 820    but I know that SR10.2 supports it.  */
 821
 822   extern void proc1_$get_loadav ();
 823   unsigned long load_ave[3];
 824
 825   proc1_$get_loadav (load_ave);
 826
 827   if (nelem > 0)
 828     loadavg[elem++] = load_ave[0] / 65536.0;
 829   if (nelem > 1)
 830     loadavg[elem++] = load_ave[1] / 65536.0;
 831   if (nelem > 2)
 832     loadavg[elem++] = load_ave[2] / 65536.0;
 833 # endif /* apollo */
 834
 835 # if !defined (LDAV_DONE) && defined (OSF_MIPS)
 836 #  define LDAV_DONE
 837
 838   struct tbl_loadavg load_ave;
 839   table (TBL_LOADAVG, 0, &load_ave, 1, sizeof (load_ave));
 840   loadavg[elem++]
 841     = (load_ave.tl_lscale == 0
 842        ? load_ave.tl_avenrun.d[0]
 843        : (load_ave.tl_avenrun.l[0] / (double) load_ave.tl_lscale));
 844 # endif /* OSF_MIPS */
 845
 846 # if !defined (LDAV_DONE) && (defined (__MSDOS__) || defined (WINDOWS32))
 847                                                            /* DJGPP */
 848 #  define LDAV_DONE
 849
 850   /* A faithful emulation is going to have to be saved for a rainy day.  */
 851   for ( ; elem < nelem; elem++)
 852     {
 853       loadavg[elem] = 0.0;
 854     }
 855 # endif  /* __MSDOS__ || WINDOWS32 */
 856
 857 # if !defined (LDAV_DONE) && defined (OSF_ALPHA)           /* OSF/1 */
 858 #  define LDAV_DONE
 859
 860   struct tbl_loadavg load_ave;
 861   table (TBL_LOADAVG, 0, &load_ave, 1, sizeof (load_ave));
 862   for (elem = 0; elem < nelem; elem++)
 863     loadavg[elem]
 864       = (load_ave.tl_lscale == 0
 865          ? load_ave.tl_avenrun.d[elem]
 866          : (load_ave.tl_avenrun.l[elem] / (double) load_ave.tl_lscale));
 867 # endif /* OSF_ALPHA */
 868
 869 # if ! defined LDAV_DONE && defined __VMS                  /* VMS */
 870   /* VMS specific code -- read from the Load Ave driver.  */
 871
 872   LOAD_AVE_TYPE load_ave[3];
 873   static bool getloadavg_initialized;
 874 #  ifdef eunice
 875   struct
 876   {
 877     int dsc$w_length;
 878     char *dsc$a_pointer;
 879   } descriptor;
 880 #  endif
 881
 882   /* Ensure that there is a channel open to the load ave device.  */
 883   if (!getloadavg_initialized)
 884     {
 885       /* Attempt to open the channel.  */
 886 #  ifdef eunice
 887       descriptor.dsc$w_length = 18;
 888       descriptor.dsc$a_pointer = "$$VMS_LOAD_AVERAGE";
 889 #  else
 890       $DESCRIPTOR (descriptor, "LAV0:");
 891 #  endif
 892       if (sys$assign (&descriptor, &channel, 0, 0) & 1)
 893         getloadavg_initialized = true;
 894     }
 895
 896   /* Read the load average vector.  */
 897   if (getloadavg_initialized
 898       && !(sys$qiow (0, channel, IO$_READVBLK, 0, 0, 0,
 899                      load_ave, 12, 0, 0, 0, 0) & 1))
 900     {
 901       sys$dassgn (channel);
 902       getloadavg_initialized = false;
 903     }
 904
 905   if (!getloadavg_initialized)
 906     {
 907       errno = ENOTSUP;
 908       return -1;
 909     }
 910 # endif /* ! defined LDAV_DONE && defined __VMS */
 911
 912 # if ! defined LDAV_DONE && defined LOAD_AVE_TYPE && ! defined __VMS
 913                                                   /* IRIX, other old systems */
 914
 915   /* UNIX-specific code -- read the average from /dev/kmem.  */
 916
 917 #  define LDAV_PRIVILEGED               /* This code requires special installation.  */
 918
 919   LOAD_AVE_TYPE load_ave[3];
 920
 921   /* Get the address of LDAV_SYMBOL.  */
 922   if (offset == 0)
 923     {
 924 #  ifndef sgi
 925 #   if ! defined NLIST_STRUCT || ! defined N_NAME_POINTER
 926       strcpy (name_list[0].n_name, LDAV_SYMBOL);
 927       strcpy (name_list[1].n_name, "");
 928 #   else /* NLIST_STRUCT */
 929 #    ifdef HAVE_STRUCT_NLIST_N_UN_N_NAME
 930       name_list[0].n_un.n_name = LDAV_SYMBOL;
 931       name_list[1].n_un.n_name = 0;
 932 #    else /* not HAVE_STRUCT_NLIST_N_UN_N_NAME */
 933       name_list[0].n_name = LDAV_SYMBOL;
 934       name_list[1].n_name = 0;
 935 #    endif /* not HAVE_STRUCT_NLIST_N_UN_N_NAME */
 936 #   endif /* NLIST_STRUCT */
 937
 938 #   ifndef SUNOS_5
 939       if (
 940 #    if !(defined (_AIX) && !defined (ps2))
 941           nlist (KERNEL_FILE, name_list)
 942 #    else  /* _AIX */
 943           knlist (name_list, 1, sizeof (name_list[0]))
 944 #    endif
 945           >= 0)
 946           /* Omit "&& name_list[0].n_type != 0 " -- it breaks on Sun386i.  */
 947           {
 948 #    ifdef FIXUP_KERNEL_SYMBOL_ADDR
 949             FIXUP_KERNEL_SYMBOL_ADDR (name_list);
 950 #    endif
 951             offset = name_list[0].n_value;
 952           }
 953 #   endif /* !SUNOS_5 */
 954 #  else  /* sgi */
 955       ptrdiff_t ldav_off = sysmp (MP_KERNADDR, MPKA_AVENRUN);
 956       if (ldav_off != -1)
 957         offset = (long int) ldav_off & 0x7fffffff;
 958 #  endif /* sgi */
 959     }
 960
 961   /* Make sure we have /dev/kmem open.  */
 962   if (!getloadavg_initialized)
 963     {
 964 #  ifndef SUNOS_5
 965       /* Set the channel to close on exec, so it does not
 966          litter any child's descriptor table.  */
 967 #   ifndef O_CLOEXEC
 968 #    define O_CLOEXEC 0
 969 #   endif
 970       int fd = open ("/dev/kmem", O_RDONLY | O_CLOEXEC);
 971       if (0 <= fd)
 972         {
 973 #   if F_DUPFD_CLOEXEC
 974           if (fd <= STDERR_FILENO)
 975             {
 976               int fd1 = fcntl (fd, F_DUPFD_CLOEXEC, STDERR_FILENO + 1);
 977               close (fd);
 978               fd = fd1;
 979             }
 980 #   endif
 981           if (0 <= fd)
 982             {
 983               channel = fd;
 984               getloadavg_initialized = true;
 985             }
 986         }
 987 #  else /* SUNOS_5 */
 988       /* We pass 0 for the kernel, corefile, and swapfile names
 989          to use the currently running kernel.  */
 990       kd = kvm_open (0, 0, 0, O_RDONLY, 0);
 991       if (kd != 0)
 992         {
 993           /* nlist the currently running kernel.  */
 994           kvm_nlist (kd, name_list);
 995           offset = name_list[0].n_value;
 996           getloadavg_initialized = true;
 997         }
 998 #  endif /* SUNOS_5 */
 999     }
1000
1001   /* If we can, get the load average values.  */
1002   if (offset && getloadavg_initialized)
1003     {
1004       /* Try to read the load.  */
1005 #  ifndef SUNOS_5
1006       if (lseek (channel, offset, 0) == -1L
1007           || read (channel, (char *) load_ave, sizeof (load_ave))
1008           != sizeof (load_ave))
1009         {
1010           close (channel);
1011           getloadavg_initialized = false;
1012         }
1013 #  else  /* SUNOS_5 */
1014       if (kvm_read (kd, offset, (char *) load_ave, sizeof (load_ave))
1015           != sizeof (load_ave))
1016         {
1017           kvm_close (kd);
1018           getloadavg_initialized = false;
1019         }
1020 #  endif /* SUNOS_5 */
1021     }
1022
1023   if (offset == 0 || !getloadavg_initialized)
1024     {
1025       errno = ENOTSUP;
1026       return -1;
1027     }
1028 # endif /* ! defined LDAV_DONE && defined LOAD_AVE_TYPE && ! defined __VMS */
1029
1030 # if !defined (LDAV_DONE) && defined (LOAD_AVE_TYPE) /* Including VMS.  */
1031   if (nelem > 0)
1032     loadavg[elem++] = LDAV_CVT (load_ave[0]);
1033   if (nelem > 1)
1034     loadavg[elem++] = LDAV_CVT (load_ave[1]);
1035   if (nelem > 2)
1036     loadavg[elem++] = LDAV_CVT (load_ave[2]);
1037
1038 #  define LDAV_DONE
1039 # endif /* !LDAV_DONE && LOAD_AVE_TYPE */
1040
1041 # if !defined LDAV_DONE
1042   errno = ENOSYS;
1043   elem = -1;
1044 # endif
1045   return elem;
1046 }