1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <asm/page.h>
30#include <bionic_tls.h>
31#include <ctype.h>
32#include <dirent.h>
33#include <errno.h>
34#include <fcntl.h>
35#include <limits.h>
36#include <stdbool.h>
37#include <stdio.h>  // For FOPEN_MAX.
38#include <string.h>
39#include <sys/sysconf.h>
40#include <unistd.h>
41
42/* seems to be the default on Linux, per the GLibc sources and my own digging */
43
44#define  SYSTEM_CLK_TCK         100
45#define  SYSTEM_IOV_MAX         1024
46#define  SYSTEM_DELAYTIMER_MAX  2147483647
47#define  SYSTEM_MQ_OPEN_MAX     8
48#define  SYSTEM_MQ_PRIO_MAX     32768
49#define  SYSTEM_SEM_NSEMS_MAX   256
50#define  SYSTEM_SEM_VALUE_MAX   0x3fffffff  /* see bionic/semaphore.c */
51#define  SYSTEM_SIGQUEUE_MAX    32
52#define  SYSTEM_TIMER_MAX       32
53#define  SYSTEM_LOGIN_NAME_MAX  256
54#define  SYSTEM_TTY_NAME_MAX    32
55
56/* the following depends on our implementation */
57#define  SYSTEM_ATEXIT_MAX          65536    /* our implementation is unlimited */
58#define  SYSTEM_THREAD_KEYS_MAX     BIONIC_TLS_SLOTS
59#define  SYSTEM_THREAD_STACK_MIN    32768    /* lower values may be possible, but be conservative */
60#define  SYSTEM_THREAD_THREADS_MAX  2048     /* really unlimited */
61
62#define  SYSTEM_2_C_BIND     _POSIX_VERSION  /* Posix C binding version */
63#define  SYSTEM_2_C_VER      _POSIX2_C_VERSION
64#define  SYSTEM_2_C_DEV      -1       /* Posix C development tools unsupported on the device */
65#define  SYSTEM_2_FORT_DEV   -1       /* Fortran development unsupported */
66#define  SYSTEM_2_FORT_RUN   -1       /* Fortran runtime unsupported */
67#define  SYSTEM_2_SW_DEV     -1       /* posix software dev utilities unsupported */
68#define  SYSTEM_2_LOCALEDEF  -1       /* localedef() unimplemented */
69#define  SYSTEM_2_UPE        -1       /* No UPE for you ! (User Portability Utilities) */
70#define  SYSTEM_2_VERSION    -1       /* No posix command-line tools */
71
72static bool __matches_cpuN(const char* s) {
73  // The %c trick is to ensure that we have the anchored match "^cpu[0-9]+$".
74  unsigned cpu;
75  char dummy;
76  return (sscanf(s, "cpu%u%c", &cpu, &dummy) == 1);
77}
78
79static int __get_nproc_conf(void) {
80  // On x86 kernels you can use /proc/cpuinfo for this, but on ARM kernels offline CPUs disappear
81  // from there. This method works on both.
82  DIR* d = opendir("/sys/devices/system/cpu");
83  if (!d) {
84    return 1;
85  }
86
87  int result = 0;
88  struct dirent de;
89  struct dirent* e;
90  while (!readdir_r(d, &de, &e) && e != NULL) {
91    if (e->d_type == DT_DIR && __matches_cpuN(e->d_name)) {
92      ++result;
93    }
94  }
95  closedir(d);
96  return result;
97}
98
99static int __get_nproc_onln(void) {
100  FILE* fp = fopen("/proc/stat", "r");
101  if (fp == NULL) {
102    return 1;
103  }
104
105  int result = 0;
106  char buf[256];
107  while (fgets(buf, sizeof(buf), fp) != NULL) {
108    // Extract just the first word from the line.
109    // 'cpu0 7976751 1364388 3116842 469770388 8629405 0 49047 0 0 0'
110    char* p = strchr(buf, ' ');
111    if (p != NULL) {
112      *p = 0;
113    }
114    if (__matches_cpuN(buf)) {
115      ++result;
116    }
117  }
118  fclose(fp);
119  return result;
120}
121
122static int __get_meminfo(const char* pattern) {
123  FILE* fp = fopen("/proc/meminfo", "r");
124  if (fp == NULL) {
125    return -1;
126  }
127
128  int result = -1;
129  char buf[256];
130  while (fgets(buf, sizeof(buf), fp) != NULL) {
131    long total;
132    if (sscanf(buf, pattern, &total) == 1) {
133      result = (int) (total / (PAGE_SIZE/1024));
134      break;
135    }
136  }
137  fclose(fp);
138  return result;
139}
140
141static int __get_phys_pages(void) {
142  return __get_meminfo("MemTotal: %ld kB");
143}
144
145static int __get_avphys_pages(void) {
146  return __get_meminfo("MemFree: %ld kB");
147}
148
149int sysconf(int name) {
150    switch (name) {
151#ifdef _POSIX_ARG_MAX
152    case _SC_ARG_MAX:           return _POSIX_ARG_MAX;
153#endif
154#ifdef _POSIX2_BC_BASE_MAX
155    case _SC_BC_BASE_MAX:       return _POSIX2_BC_BASE_MAX;
156#endif
157#ifdef _POSIX2_BC_DIM_MAX
158    case _SC_BC_DIM_MAX:        return _POSIX2_BC_DIM_MAX;
159#endif
160#ifdef _POSIX2_BC_SCALE_MAX
161    case _SC_BC_SCALE_MAX:      return _POSIX2_BC_SCALE_MAX;
162#endif
163#ifdef _POSIX2_BC_STRING_MAX
164    case _SC_BC_STRING_MAX:     return _POSIX2_BC_STRING_MAX;
165#endif
166    case _SC_CHILD_MAX:         return CHILD_MAX;
167    case _SC_CLK_TCK:           return SYSTEM_CLK_TCK;
168#ifdef _POSIX2_COLL_WEIGHTS_MASK
169    case _SC_COLL_WEIGHTS_MAX:  return _POSIX2_COLL_WEIGHTS_MASK;
170#endif
171#ifdef _POSIX2_EXPR_NEST_MAX
172    case _SC_EXPR_NEST_MAX:    return _POSIX2_EXPR_NEST_MAX;
173#endif
174#ifdef _POSIX2_LINE_MAX
175    case _SC_LINE_MAX:          return _POSIX2_LINE_MAX;
176#endif
177    case _SC_NGROUPS_MAX:       return NGROUPS_MAX;
178    case _SC_OPEN_MAX:          return OPEN_MAX;
179    //case _SC_PASS_MAX:          return PASS_MAX;
180    case _SC_2_C_BIND:          return SYSTEM_2_C_BIND;
181    case _SC_2_C_DEV:           return SYSTEM_2_C_DEV;
182    case _SC_2_C_VERSION:       return SYSTEM_2_C_VER;
183    //case _SC_2_CHAR_TERM:         return ;
184    case _SC_2_FORT_DEV:        return SYSTEM_2_FORT_DEV;
185    case _SC_2_FORT_RUN:        return SYSTEM_2_FORT_RUN;
186    case _SC_2_LOCALEDEF:       return SYSTEM_2_LOCALEDEF;
187    case _SC_2_SW_DEV:          return SYSTEM_2_SW_DEV;
188    case _SC_2_UPE:             return SYSTEM_2_UPE;
189    case _SC_2_VERSION:         return SYSTEM_2_VERSION;
190#ifdef _POSIX_JOB_CONTROL
191    case _SC_JOB_CONTROL:       return _POSIX_JOB_CONTROL;
192#endif
193#ifdef _POSIX_SAVED_IDS
194    case _SC_SAVED_IDS:         return _POSIX_SAVED_IDS;
195#endif
196#ifdef _POSIX_VERSION
197    case _SC_VERSION:           return _POSIX_VERSION;
198#endif
199    //case _SC_RE_DUP_<AX:        return ;
200    case _SC_STREAM_MAX:        return FOPEN_MAX;
201    //case _SC_TZNAME_MAX:        return ;
202#if _XOPEN_CRYPT
203    case _SC_XOPEN_CRYPT:       return _XOPEN_CRYPT;
204#endif
205#ifdef _XOPEN_ENH_I18N
206    case _SC_XOPEN_ENH_I18N:    return _XOPEN_ENH_I18N;
207#endif
208#ifdef _XOPEN_SHM
209    case _SC_XOPEN_SHM:         return _XOPEN_SHM;
210#endif
211#ifdef _XOPEN_VERSION
212    case _SC_XOPEN_VERSION:     return _XOPEN_VERSION;
213#endif
214#ifdef _XOPEN_XCU_VERSION
215    case _SC_XOPEN_XCU_VERSION: return _XOPEN_XCU_VERSION;
216#endif
217#ifdef _XOPEN_REALTIME
218    case _SC_XOPEN_REALTIME:    return _XOPEN_REALTIME;
219#endif
220#ifdef _XOPEN_REALTIME_THREADS
221    case _SC_XOPEN_REALTIME_THREADS: return _XOPEN_REALTIME_THREADS;
222#endif
223#ifdef _XOPEN_LEGACY
224    case _SC_XOPEN_LEGACY:      return _XOPEN_LEGACY;
225#endif
226    case _SC_ATEXIT_MAX:        return SYSTEM_ATEXIT_MAX;
227    case _SC_IOV_MAX:           return SYSTEM_IOV_MAX;
228    case _SC_PAGESIZE:          return PAGE_SIZE;
229    case _SC_PAGE_SIZE:         return PAGE_SIZE;
230#ifdef _XOPEN_UNIX
231    case _SC_XOPEN_UNIX:        return _XOPEN_UNIX;
232#endif
233
234    // XXX: TODO: XBS5 nonsense
235
236#ifdef AIO_LISTIO_MAX
237    case _SC_AIO_LISTIO_MAX:       return AIO_LISTIO_MAX;
238#endif
239#ifdef AIO_MAX
240    case _SC_AIO_MAX:              return AIO_MAX;
241#endif
242#ifdef AIO_PRIO_DELTA_MAX
243    case _SC_AIO_PRIO_DELTA_MAX:   return AIO_PRIO_DELTA_MAX;
244#endif
245    case _SC_DELAYTIMER_MAX:    return SYSTEM_DELAYTIMER_MAX;
246    case _SC_MQ_OPEN_MAX:       return SYSTEM_MQ_OPEN_MAX;
247    case _SC_MQ_PRIO_MAX:       return SYSTEM_MQ_PRIO_MAX;
248    case _SC_RTSIG_MAX:         return RTSIG_MAX;
249    case _SC_SEM_NSEMS_MAX:     return SYSTEM_SEM_NSEMS_MAX;
250    case _SC_SEM_VALUE_MAX:     return SYSTEM_SEM_VALUE_MAX;
251    case _SC_SIGQUEUE_MAX:      return SYSTEM_SIGQUEUE_MAX;
252    case _SC_TIMER_MAX:         return SYSTEM_TIMER_MAX;
253#ifdef _POSIX_ASYNCHRONOUS_IO
254    case _SC_ASYNCHRONOUS_IO:   return _POSIX_ASYNCHRONOUS_IO;
255#endif
256#ifdef _POSIX_FSYNC
257    case _SC_FSYNC:             return _POSIX_FSYNC;
258#endif
259#ifdef _POSIX_MAPPED_FILES
260    case _SC_MAPPED_FILES:      return _POSIX_MAPPED_FILES;
261#endif
262#ifdef _POSIX_MEMLOCK
263    case _SC_MEMLOCK:           return _POSIX_MEMLOCK;
264#endif
265#ifdef _POSIX_MEMLOCK_RANGE
266    case _SC_MEMLOCK_RANGE:     return _POSIX_MEMLOCK_RANGE
267#endif
268#ifdef _POSIX_MEMORY_PROTECTION
269    case _SC_MEMORY_PROTECTION: return _POSIX_MEMORY_PROTECTION;
270#endif
271#ifdef _POSIX_MESSAGE_PASSING
272    case _SC_MESSAGE_PASSING:   return _POSIX_MESSAGE_PASSING;
273#endif
274#ifdef _POSIX_PRIORITIZED_IO
275    case _SC_PRIORITIZED_IO:    return _POSIX_PRIORITIZED_IO;
276#endif
277#ifdef _POSIX_PRIORITY_SCHEDULING
278    case _SC_PRIORITY_SCHEDULING:  return _POSIX_PRIORITY_SCHEDULING;
279#endif
280#ifdef _POSIX_REALTIME_SIGNALS
281    case _SC_REALTIME_SIGNALS:  return _POSIX_REALTIME_SIGNALS;
282#endif
283#ifdef _POSIX_SEMAPHORES
284    case _SC_SEMAPHORES:        return _POSIX_SEMAPHORES;
285#endif
286#ifdef _POSIX_SHARED_MEMORY_OBJECTS
287    case _SC_SHARED_MEMORY_OBJECTS:  return _POSIX_SHARED_MEMORY_OBJECTS;
288#endif
289#ifdef _POSIX_SYNCHRONIZED_IO
290    case _SC_SYNCHRONIZED_IO:   return _POSIX_SYNCHRONIZED_IO;
291#endif
292#ifdef _POSIX_TIMERS
293    case _SC_TIMERS:            return _POSIX_TIMERS;
294#endif
295
296    // GETGR_R_SIZE_MAX ?
297    // GETPW_R_SIZE_MAX ?
298
299    case _SC_LOGIN_NAME_MAX:    return SYSTEM_LOGIN_NAME_MAX;
300#ifdef _POSIX_THREAD_DESTRUCTOR_ITERATIONS
301    case _SC_THREAD_DESTRUCTOR_ITERATIONS:  return _POSIX_THREAD_DESTRUCTOR_ITERATIONS;
302#endif
303    case _SC_THREAD_KEYS_MAX:     return SYSTEM_THREAD_KEYS_MAX;
304    case _SC_THREAD_STACK_MIN:    return SYSTEM_THREAD_STACK_MIN;
305    case _SC_THREAD_THREADS_MAX:  return SYSTEM_THREAD_THREADS_MAX;
306    case _SC_TTY_NAME_MAX:        return SYSTEM_TTY_NAME_MAX;
307#ifdef _POSIX_THREADS
308    case _SC_THREADS:             return _POSIX_THREADS;
309#endif
310#ifdef _POSIX_THREAD_ATTR_STACKADDR
311    case _SC_THREAD_ATTR_STACKADDR:   return _POSIX_THREAD_ATTR_STACKADDR;
312#endif
313#ifdef _POSIX_THREAD_ATTR_STACKSIZE
314    case _SC_THREAD_ATTR_STACKSIZE:   return _POSIX_THREAD_ATTR_STACKSIZE;
315#endif
316#ifdef _POSIX_THREAD_PRIORITY_SCHEDULING
317    case _SC_THREAD_PRIORITY_SCHEDULING:  return _POSIX_THREAD_PRIORITY_SCHEDULING;
318#endif
319#ifdef _POSIX_THREAD_PRIO_INHERIT
320    case _SC_THREAD_PRIO_INHERIT:         return _POSIX_THREAD_PRIO_INHERIT;
321#endif
322#ifdef _POSIX_THREAD_PRIO_PROTECT
323    case _SC_THREAD_PRIO_PROTECT: return _POSIX_THREAD_PRIO_PROTECT;
324#endif
325#ifdef _POSIX_THREAD_SAFE_FUNCTIONS
326    case _SC_THREAD_SAFE_FUNCTIONS:  return _POSIX_THREAD_SAFE_FUNCTIONS
327#endif
328
329
330    case _SC_NPROCESSORS_CONF:  return __get_nproc_conf();
331    case _SC_NPROCESSORS_ONLN:  return __get_nproc_onln();
332    case _SC_PHYS_PAGES:        return __get_phys_pages();
333    case _SC_AVPHYS_PAGES:      return __get_avphys_pages();
334
335    default:
336       /* Posix says EINVAL is the only error that shall be returned,
337        * but GLibc uses ENOSYS */
338        errno = ENOSYS;
339        return -1;
340    }
341}
342