summaryrefslogtreecommitdiffstats
path: root/libc/bionic/sysconf.cpp
blob: 8309f087acafb38f946e4a48f42d26aa3cb7ca13 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
/*
 * Copyright (C) 2008 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <ctype.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <pthread.h>
#include <stdio.h>  // For FOPEN_MAX.
#include <string.h>
#include <sys/sysconf.h>
#include <time.h>
#include <unistd.h>

#include "private/bionic_tls.h"
#include "private/ScopedReaddir.h"

/* seems to be the default on Linux, per the GLibc sources and my own digging */

#define  SYSTEM_CLK_TCK         100
#define  SYSTEM_IOV_MAX         1024
#define  SYSTEM_DELAYTIMER_MAX  2147483647
#define  SYSTEM_MQ_OPEN_MAX     8
#define  SYSTEM_MQ_PRIO_MAX     32768
#define  SYSTEM_SEM_NSEMS_MAX   256
#define  SYSTEM_SEM_VALUE_MAX   0x3fffffff  /* see bionic/semaphore.c */
#define  SYSTEM_SIGQUEUE_MAX    32
#define  SYSTEM_TIMER_MAX       32
#define  SYSTEM_LOGIN_NAME_MAX  256
#define  SYSTEM_TTY_NAME_MAX    32

/* the following depends on our implementation */
#define  SYSTEM_ATEXIT_MAX          65536    /* our implementation is unlimited */
#define  SYSTEM_THREAD_THREADS_MAX  2048     /* really unlimited */

#define  SYSTEM_2_C_BIND     _POSIX_VERSION  /* Posix C binding version */
#define  SYSTEM_2_C_VER      _POSIX2_C_VERSION
#define  SYSTEM_2_C_DEV      -1       /* Posix C development tools unsupported on the device */
#define  SYSTEM_2_FORT_DEV   -1       /* Fortran development unsupported */
#define  SYSTEM_2_FORT_RUN   -1       /* Fortran runtime unsupported */
#define  SYSTEM_2_SW_DEV     -1       /* posix software dev utilities unsupported */
#define  SYSTEM_2_LOCALEDEF  -1       /* localedef() unimplemented */
#define  SYSTEM_2_UPE        -1       /* No UPE for you ! (User Portability Utilities) */
#define  SYSTEM_2_VERSION    -1       /* No posix command-line tools */

static bool __matches_cpuN(const char* s) {
  // The %c trick is to ensure that we have the anchored match "^cpu[0-9]+$".
  unsigned cpu;
  char dummy;
  return (sscanf(s, "cpu%u%c", &cpu, &dummy) == 1);
}

static int __sysconf_nprocessors_conf() {
  // On x86 kernels you can use /proc/cpuinfo for this, but on ARM kernels offline CPUs disappear
  // from there. This method works on both.
  ScopedReaddir reader("/sys/devices/system/cpu");
  if (reader.IsBad()) {
    return 1;
  }

  int result = 0;
  dirent* entry;
  while ((entry = reader.ReadEntry()) != NULL) {
    if (entry->d_type == DT_DIR && __matches_cpuN(entry->d_name)) {
      ++result;
    }
  }
  return result;
}

static int __sysconf_nprocessors_onln() {
  FILE* fp = fopen("/proc/stat", "r");
  if (fp == NULL) {
    return 1;
  }

  int result = 0;
  char buf[256];
  while (fgets(buf, sizeof(buf), fp) != NULL) {
    // Extract just the first word from the line.
    // 'cpu0 7976751 1364388 3116842 469770388 8629405 0 49047 0 0 0'
    char* p = strchr(buf, ' ');
    if (p != NULL) {
      *p = 0;
    }
    if (__matches_cpuN(buf)) {
      ++result;
    }
  }
  fclose(fp);
  return result;
}

static int __get_meminfo(const char* pattern) {
  FILE* fp = fopen("/proc/meminfo", "r");
  if (fp == NULL) {
    return -1;
  }

  int result = -1;
  char buf[256];
  while (fgets(buf, sizeof(buf), fp) != NULL) {
    long total;
    if (sscanf(buf, pattern, &total) == 1) {
      result = (int) (total / (PAGE_SIZE/1024));
      break;
    }
  }
  fclose(fp);
  return result;
}

static int __sysconf_phys_pages() {
  return __get_meminfo("MemTotal: %ld kB");
}

static int __sysconf_avphys_pages() {
  return __get_meminfo("MemFree: %ld kB");
}

static int __sysconf_monotonic_clock() {
  timespec t;
  int rc = clock_getres(CLOCK_MONOTONIC, &t);
  return (rc == -1) ? -1 : _POSIX_VERSION;
}

int sysconf(int name) {
    switch (name) {
#ifdef _POSIX_ARG_MAX
    case _SC_ARG_MAX:           return _POSIX_ARG_MAX;
#endif
#ifdef _POSIX2_BC_BASE_MAX
    case _SC_BC_BASE_MAX:       return _POSIX2_BC_BASE_MAX;
#endif
#ifdef _POSIX2_BC_DIM_MAX
    case _SC_BC_DIM_MAX:        return _POSIX2_BC_DIM_MAX;
#endif
#ifdef _POSIX2_BC_SCALE_MAX
    case _SC_BC_SCALE_MAX:      return _POSIX2_BC_SCALE_MAX;
#endif
#ifdef _POSIX2_BC_STRING_MAX
    case _SC_BC_STRING_MAX:     return _POSIX2_BC_STRING_MAX;
#endif
    case _SC_CHILD_MAX:         return CHILD_MAX;
    case _SC_CLK_TCK:           return SYSTEM_CLK_TCK;
#ifdef _POSIX2_COLL_WEIGHTS_MASK
    case _SC_COLL_WEIGHTS_MAX:  return _POSIX2_COLL_WEIGHTS_MASK;
#endif
#ifdef _POSIX2_EXPR_NEST_MAX
    case _SC_EXPR_NEST_MAX:    return _POSIX2_EXPR_NEST_MAX;
#endif
#ifdef _POSIX2_LINE_MAX
    case _SC_LINE_MAX:          return _POSIX2_LINE_MAX;
#endif
    case _SC_NGROUPS_MAX:       return NGROUPS_MAX;
    case _SC_OPEN_MAX:          return OPEN_MAX;
    //case _SC_PASS_MAX:          return PASS_MAX;
    case _SC_2_C_BIND:          return SYSTEM_2_C_BIND;
    case _SC_2_C_DEV:           return SYSTEM_2_C_DEV;
    case _SC_2_C_VERSION:       return SYSTEM_2_C_VER;
    //case _SC_2_CHAR_TERM:         return ;
    case _SC_2_FORT_DEV:        return SYSTEM_2_FORT_DEV;
    case _SC_2_FORT_RUN:        return SYSTEM_2_FORT_RUN;
    case _SC_2_LOCALEDEF:       return SYSTEM_2_LOCALEDEF;
    case _SC_2_SW_DEV:          return SYSTEM_2_SW_DEV;
    case _SC_2_UPE:             return SYSTEM_2_UPE;
    case _SC_2_VERSION:         return SYSTEM_2_VERSION;
#ifdef _POSIX_JOB_CONTROL
    case _SC_JOB_CONTROL:       return _POSIX_JOB_CONTROL;
#endif
#ifdef _POSIX_SAVED_IDS
    case _SC_SAVED_IDS:         return _POSIX_SAVED_IDS;
#endif
#ifdef _POSIX_VERSION
    case _SC_VERSION:           return _POSIX_VERSION;
#endif
    //case _SC_RE_DUP_<AX:        return ;
    case _SC_STREAM_MAX:        return FOPEN_MAX;
    //case _SC_TZNAME_MAX:        return ;
#if _XOPEN_CRYPT
    case _SC_XOPEN_CRYPT:       return _XOPEN_CRYPT;
#endif
#ifdef _XOPEN_ENH_I18N
    case _SC_XOPEN_ENH_I18N:    return _XOPEN_ENH_I18N;
#endif
#ifdef _XOPEN_SHM
    case _SC_XOPEN_SHM:         return _XOPEN_SHM;
#endif
#ifdef _XOPEN_VERSION
    case _SC_XOPEN_VERSION:     return _XOPEN_VERSION;
#endif
#ifdef _XOPEN_XCU_VERSION
    case _SC_XOPEN_XCU_VERSION: return _XOPEN_XCU_VERSION;
#endif
#ifdef _XOPEN_REALTIME
    case _SC_XOPEN_REALTIME:    return _XOPEN_REALTIME;
#endif
#ifdef _XOPEN_REALTIME_THREADS
    case _SC_XOPEN_REALTIME_THREADS: return _XOPEN_REALTIME_THREADS;
#endif
#ifdef _XOPEN_LEGACY
    case _SC_XOPEN_LEGACY:      return _XOPEN_LEGACY;
#endif
    case _SC_ATEXIT_MAX:        return SYSTEM_ATEXIT_MAX;
    case _SC_IOV_MAX:           return SYSTEM_IOV_MAX;

    case _SC_PAGESIZE:
    case _SC_PAGE_SIZE:
        return PAGE_SIZE;

#ifdef _XOPEN_UNIX
    case _SC_XOPEN_UNIX:        return _XOPEN_UNIX;
#endif

    // XXX: TODO: XBS5 nonsense

#ifdef AIO_LISTIO_MAX
    case _SC_AIO_LISTIO_MAX:       return AIO_LISTIO_MAX;
#endif
#ifdef AIO_MAX
    case _SC_AIO_MAX:              return AIO_MAX;
#endif
#ifdef AIO_PRIO_DELTA_MAX
    case _SC_AIO_PRIO_DELTA_MAX:   return AIO_PRIO_DELTA_MAX;
#endif
    case _SC_DELAYTIMER_MAX:    return SYSTEM_DELAYTIMER_MAX;
    case _SC_MQ_OPEN_MAX:       return SYSTEM_MQ_OPEN_MAX;
    case _SC_MQ_PRIO_MAX:       return SYSTEM_MQ_PRIO_MAX;
    case _SC_RTSIG_MAX:         return RTSIG_MAX;
    case _SC_SEM_NSEMS_MAX:     return SYSTEM_SEM_NSEMS_MAX;
    case _SC_SEM_VALUE_MAX:     return SYSTEM_SEM_VALUE_MAX;
    case _SC_SIGQUEUE_MAX:      return SYSTEM_SIGQUEUE_MAX;
    case _SC_TIMER_MAX:         return SYSTEM_TIMER_MAX;
#ifdef _POSIX_ASYNCHRONOUS_IO
    case _SC_ASYNCHRONOUS_IO:   return _POSIX_ASYNCHRONOUS_IO;
#endif
#ifdef _POSIX_FSYNC
    case _SC_FSYNC:             return _POSIX_FSYNC;
#endif
#ifdef _POSIX_MAPPED_FILES
    case _SC_MAPPED_FILES:      return _POSIX_MAPPED_FILES;
#endif
#ifdef _POSIX_MEMLOCK
    case _SC_MEMLOCK:           return _POSIX_MEMLOCK;
#endif
#ifdef _POSIX_MEMLOCK_RANGE
    case _SC_MEMLOCK_RANGE:     return _POSIX_MEMLOCK_RANGE
#endif
#ifdef _POSIX_MEMORY_PROTECTION
    case _SC_MEMORY_PROTECTION: return _POSIX_MEMORY_PROTECTION;
#endif
#ifdef _POSIX_MESSAGE_PASSING
    case _SC_MESSAGE_PASSING:   return _POSIX_MESSAGE_PASSING;
#endif
#ifdef _POSIX_PRIORITIZED_IO
    case _SC_PRIORITIZED_IO:    return _POSIX_PRIORITIZED_IO;
#endif
#ifdef _POSIX_PRIORITY_SCHEDULING
    case _SC_PRIORITY_SCHEDULING:  return _POSIX_PRIORITY_SCHEDULING;
#endif
#ifdef _POSIX_REALTIME_SIGNALS
    case _SC_REALTIME_SIGNALS:  return _POSIX_REALTIME_SIGNALS;
#endif
#ifdef _POSIX_SEMAPHORES
    case _SC_SEMAPHORES:        return _POSIX_SEMAPHORES;
#endif
#ifdef _POSIX_SHARED_MEMORY_OBJECTS
    case _SC_SHARED_MEMORY_OBJECTS:  return _POSIX_SHARED_MEMORY_OBJECTS;
#endif
#ifdef _POSIX_SYNCHRONIZED_IO
    case _SC_SYNCHRONIZED_IO:   return _POSIX_SYNCHRONIZED_IO;
#endif
#ifdef _POSIX_TIMERS
    case _SC_TIMERS:            return _POSIX_TIMERS;
#endif

    case _SC_GETGR_R_SIZE_MAX: return 1024;
    case _SC_GETPW_R_SIZE_MAX: return 1024;

    case _SC_LOGIN_NAME_MAX:    return SYSTEM_LOGIN_NAME_MAX;

    case _SC_THREAD_DESTRUCTOR_ITERATIONS:
      return _POSIX_THREAD_DESTRUCTOR_ITERATIONS;

    case _SC_THREAD_KEYS_MAX:
      return (BIONIC_TLS_SLOTS - TLS_SLOT_FIRST_USER_SLOT - BIONIC_TLS_RESERVED_SLOTS);

    case _SC_THREAD_STACK_MIN:    return PTHREAD_STACK_MIN;
    case _SC_THREAD_THREADS_MAX:  return SYSTEM_THREAD_THREADS_MAX;
    case _SC_TTY_NAME_MAX:        return SYSTEM_TTY_NAME_MAX;
#ifdef _POSIX_THREADS
    case _SC_THREADS:             return _POSIX_THREADS;
#endif

    case _SC_THREAD_ATTR_STACKADDR:   return -1; // Removed in POSIX 2008
    case _SC_THREAD_ATTR_STACKSIZE:   return -1; // Removed in POSIX 2008

#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
    case _SC_THREAD_PRIORITY_SCHEDULING:  return _POSIX_THREAD_PRIORITY_SCHEDULING;
#endif
#ifdef _POSIX_THREAD_PRIO_INHERIT
    case _SC_THREAD_PRIO_INHERIT:         return _POSIX_THREAD_PRIO_INHERIT;
#endif
#ifdef _POSIX_THREAD_PRIO_PROTECT
    case _SC_THREAD_PRIO_PROTECT: return _POSIX_THREAD_PRIO_PROTECT;
#endif
#ifdef _POSIX_THREAD_SAFE_FUNCTIONS
    case _SC_THREAD_SAFE_FUNCTIONS:  return _POSIX_THREAD_SAFE_FUNCTIONS
#endif

    case _SC_MONOTONIC_CLOCK:   return __sysconf_monotonic_clock();
    case _SC_NPROCESSORS_CONF:  return __sysconf_nprocessors_conf();
    case _SC_NPROCESSORS_ONLN:  return __sysconf_nprocessors_onln();
    case _SC_PHYS_PAGES:        return __sysconf_phys_pages();
    case _SC_AVPHYS_PAGES:      return __sysconf_avphys_pages();

    default:
       /* Posix says EINVAL is the only error that shall be returned,
        * but GLibc uses ENOSYS */
        errno = ENOSYS;
        return -1;
    }
}