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 <errno.h>
30 #include <fcntl.h>
31 #include <limits.h>
32 #include <pthread.h>
33 #include <stdio.h> // For FOPEN_MAX.
34 #include <sys/auxv.h>
35 #include <sys/param.h>
36 #include <sys/resource.h>
37 #include <sys/sysinfo.h>
38 #include <time.h>
39 #include <unistd.h>
40
41 #include "platform/bionic/page.h"
42 #include "private/bionic_tls.h"
43
44 struct sysconf_cache {
45 long size, assoc, linesize;
46
from_size_and_geometrysysconf_cache47 static sysconf_cache from_size_and_geometry(int size_id, int geometry_id) {
48 sysconf_cache result;
49 result.size = getauxval(size_id);
50 unsigned long geometry = getauxval(geometry_id);
51 result.assoc = geometry >> 16;
52 result.linesize = geometry & 0xffff;
53 return result;
54 }
55 };
56
57 struct sysconf_caches {
58 sysconf_cache l1_i, l1_d, l2, l3, l4;
59 };
60
61 #if defined(__riscv)
62
__sysconf_caches()63 static sysconf_caches* __sysconf_caches() {
64 static sysconf_caches cached = []{
65 sysconf_caches info = {};
66 // riscv64 kernels conveniently hand us all this information.
67 info.l1_i = sysconf_cache::from_size_and_geometry(AT_L1I_CACHESIZE, AT_L1I_CACHEGEOMETRY);
68 info.l1_d = sysconf_cache::from_size_and_geometry(AT_L1D_CACHESIZE, AT_L1D_CACHEGEOMETRY);
69 info.l2 = sysconf_cache::from_size_and_geometry(AT_L2_CACHESIZE, AT_L2_CACHEGEOMETRY);
70 info.l3 = sysconf_cache::from_size_and_geometry(AT_L3_CACHESIZE, AT_L3_CACHEGEOMETRY);
71 return info;
72 }();
73 return &cached;
74 }
75
76 #elif defined(__aarch64__)
77
__sysconf_caches()78 static sysconf_caches* __sysconf_caches() {
79 static sysconf_caches cached = []{
80 sysconf_caches info = {};
81 // arm64 is especially limited. We can infer the L1 line sizes, but that's it.
82 uint64_t ctr_el0;
83 __asm__ __volatile__("mrs %0, ctr_el0" : "=r"(ctr_el0));
84 info.l1_i.linesize = 4 << (ctr_el0 & 0xf);
85 info.l1_d.linesize = 4 << ((ctr_el0 >> 16) & 0xf);
86 return info;
87 }();
88 return &cached;
89 }
90
91 #else
92
__sysconf_fread_long(const char * path)93 static long __sysconf_fread_long(const char* path) {
94 long result = 0;
95 FILE* fp = fopen(path, "re");
96 if (fp != nullptr) {
97 fscanf(fp, "%ld", &result);
98 fclose(fp);
99 }
100 return result;
101 }
102
__sysconf_caches()103 static sysconf_caches* __sysconf_caches() {
104 static sysconf_caches cached = []{
105 sysconf_caches info = {};
106 char path[64];
107 for (int i = 0; i < 4; i++) {
108 sysconf_cache c;
109
110 snprintf(path, sizeof(path), "/sys/devices/system/cpu/cpu0/cache/index%d/size", i);
111 c.size = __sysconf_fread_long(path) * 1024;
112 if (c.size == 0) break;
113
114 snprintf(path, sizeof(path), "/sys/devices/system/cpu/cpu0/cache/index%d/ways_of_associativity", i);
115 c.assoc = __sysconf_fread_long(path);
116
117 snprintf(path, sizeof(path), "/sys/devices/system/cpu/cpu0/cache/index%d/coherency_line_size", i);
118 c.linesize = __sysconf_fread_long(path);
119
120 snprintf(path, sizeof(path), "/sys/devices/system/cpu/cpu0/cache/index%d/level", i);
121 int level = __sysconf_fread_long(path);
122 if (level == 1) {
123 snprintf(path, sizeof(path), "/sys/devices/system/cpu/cpu0/cache/index%d/type", i);
124 FILE* fp = fopen(path, "re");
125 char type = fgetc(fp);
126 fclose(fp);
127 if (type == 'D') {
128 info.l1_d = c;
129 } else if (type == 'I') {
130 info.l1_i = c;
131 }
132 } else if (level == 2) {
133 info.l2 = c;
134 } else if (level == 3) {
135 info.l3 = c;
136 }
137 }
138 return info;
139 }();
140 return &cached;
141 }
142
143 #endif
144
__sysconf_rlimit(int resource)145 static long __sysconf_rlimit(int resource) {
146 rlimit rl;
147 getrlimit(resource, &rl);
148 return rl.rlim_cur;
149 }
150
sysconf(int name)151 long sysconf(int name) {
152 switch (name) {
153 //
154 // Things we actually have to calculate...
155 //
156 case _SC_ARG_MAX:
157 // You might think that just returning a constant 128KiB (ARG_MAX) would
158 // make sense, as this guy did:
159 //
160 // https://lkml.org/lkml/2017/11/15/813...
161 //
162 // I suspect a 128kB sysconf(_SC_ARG_MAX) is the sanest bet, simply
163 // because of that "conservative is better than aggressive".
164 //
165 // Especially since _technically_ we're still limiting things to that
166 // 128kB due to the single-string limit.
167 //
168 // Linus
169 //
170 // In practice that caused us trouble with toybox tests for xargs edge
171 // cases. The tests assume that they can at least reach the kernel's
172 // "minimum maximum" of 128KiB, but if we report 128KiB for _SC_ARG_MAX
173 // and xargs starts subtracting the environment space and so on from that,
174 // then xargs will think it's run out of space when given 128KiB of data,
175 // which should always work. See this thread for more:
176 //
177 // http://lists.landley.net/pipermail/toybox-landley.net/2019-November/011229.html
178 //
179 // So let's resign ourselves to tracking what the kernel actually does.
180 // Right now (2019, Linux 5.3) that amounts to:
181 return MAX(MIN(__sysconf_rlimit(RLIMIT_STACK) / 4, 3 * _STK_LIM / 4), ARG_MAX);
182
183 case _SC_AVPHYS_PAGES: return get_avphys_pages();
184 case _SC_CHILD_MAX: return __sysconf_rlimit(RLIMIT_NPROC);
185 case _SC_CLK_TCK:
186 return static_cast<long>(getauxval(AT_CLKTCK));
187 case _SC_NPROCESSORS_CONF: return get_nprocs_conf();
188 case _SC_NPROCESSORS_ONLN: return get_nprocs();
189 case _SC_OPEN_MAX: return __sysconf_rlimit(RLIMIT_NOFILE);
190
191 case _SC_PAGESIZE:
192 case _SC_PAGE_SIZE:
193 // _SC_PAGESIZE and _SC_PAGE_SIZE are distinct, but return the same value.
194 return getpagesize();
195
196 case _SC_PHYS_PAGES: return get_phys_pages();
197
198 //
199 // Constants...
200 //
201 case _SC_BC_BASE_MAX: return _POSIX2_BC_BASE_MAX; // Minimum requirement.
202 case _SC_BC_DIM_MAX: return _POSIX2_BC_DIM_MAX; // Minimum requirement.
203 case _SC_BC_SCALE_MAX: return _POSIX2_BC_SCALE_MAX; // Minimum requirement.
204 case _SC_BC_STRING_MAX: return _POSIX2_BC_STRING_MAX; // Minimum requirement.
205 case _SC_COLL_WEIGHTS_MAX: return _POSIX2_COLL_WEIGHTS_MAX; // Minimum requirement.
206 case _SC_EXPR_NEST_MAX: return _POSIX2_EXPR_NEST_MAX; // Minimum requirement.
207 case _SC_LINE_MAX: return _POSIX2_LINE_MAX; // Minimum requirement.
208 case _SC_NGROUPS_MAX:
209 // Only root can read /proc/sys/kernel/ngroups_max on Android, and groups
210 // are vestigial anyway, so the "maximum maximum" of NGROUPS_MAX is a good
211 // enough answer for _SC_NGROUPS_MAX...
212 return NGROUPS_MAX;
213 case _SC_PASS_MAX: return PASS_MAX;
214 case _SC_2_C_BIND: return _POSIX2_C_BIND;
215 case _SC_2_C_DEV: return _POSIX2_C_DEV;
216 case _SC_2_CHAR_TERM: return _POSIX2_CHAR_TERM;
217 case _SC_2_FORT_DEV: return -1;
218 case _SC_2_FORT_RUN: return -1;
219 case _SC_2_LOCALEDEF: return _POSIX2_LOCALEDEF;
220 case _SC_2_SW_DEV: return _POSIX2_SW_DEV;
221 case _SC_2_UPE: return _POSIX2_UPE;
222 case _SC_2_VERSION: return _POSIX2_VERSION;
223 case _SC_JOB_CONTROL: return _POSIX_JOB_CONTROL;
224 case _SC_SAVED_IDS: return _POSIX_SAVED_IDS;
225 case _SC_VERSION: return _POSIX_VERSION;
226 case _SC_RE_DUP_MAX: return _POSIX_RE_DUP_MAX; // Minimum requirement.
227 case _SC_STREAM_MAX: return FOPEN_MAX;
228 case _SC_TZNAME_MAX: return _POSIX_TZNAME_MAX; // Minimum requirement.
229 case _SC_XOPEN_CRYPT: return _XOPEN_CRYPT;
230 case _SC_XOPEN_ENH_I18N: return _XOPEN_ENH_I18N;
231 case _SC_XOPEN_SHM: return _XOPEN_SHM;
232 case _SC_XOPEN_VERSION: return _XOPEN_VERSION;
233 case _SC_XOPEN_REALTIME: return _XOPEN_REALTIME;
234 case _SC_XOPEN_REALTIME_THREADS: return _XOPEN_REALTIME_THREADS;
235 case _SC_XOPEN_LEGACY: return _XOPEN_LEGACY;
236 case _SC_ATEXIT_MAX: return LONG_MAX; // Unlimited.
237 case _SC_IOV_MAX: return IOV_MAX;
238
239 case _SC_XOPEN_UNIX: return _XOPEN_UNIX;
240 case _SC_AIO_LISTIO_MAX: return _POSIX_AIO_LISTIO_MAX; // Minimum requirement.
241 case _SC_AIO_MAX: return _POSIX_AIO_MAX; // Minimum requirement.
242 case _SC_AIO_PRIO_DELTA_MAX:return 0; // Minimum requirement.
243 case _SC_DELAYTIMER_MAX: return _POSIX_DELAYTIMER_MAX;
244 case _SC_MQ_OPEN_MAX: return _POSIX_MQ_OPEN_MAX; // Minimum requirement.
245 case _SC_MQ_PRIO_MAX: return _POSIX_MQ_PRIO_MAX; // Minimum requirement.
246 case _SC_RTSIG_MAX: return RTSIG_MAX;
247 case _SC_SEM_NSEMS_MAX: return _POSIX_SEM_NSEMS_MAX; // Minimum requirement.
248 case _SC_SEM_VALUE_MAX: return SEM_VALUE_MAX;
249 case _SC_SIGQUEUE_MAX: return _POSIX_SIGQUEUE_MAX; // Minimum requirement.
250 case _SC_TIMER_MAX: return _POSIX_TIMER_MAX; // Minimum requirement.
251 case _SC_ASYNCHRONOUS_IO: return _POSIX_ASYNCHRONOUS_IO;
252 case _SC_FSYNC: return _POSIX_FSYNC;
253 case _SC_MAPPED_FILES: return _POSIX_MAPPED_FILES;
254 case _SC_MEMLOCK: return _POSIX_MEMLOCK;
255 case _SC_MEMLOCK_RANGE: return _POSIX_MEMLOCK_RANGE;
256 case _SC_MEMORY_PROTECTION: return _POSIX_MEMORY_PROTECTION;
257 case _SC_MESSAGE_PASSING: return _POSIX_MESSAGE_PASSING;
258 case _SC_PRIORITIZED_IO: return _POSIX_PRIORITIZED_IO;
259 case _SC_PRIORITY_SCHEDULING: return _POSIX_PRIORITY_SCHEDULING;
260 case _SC_REALTIME_SIGNALS: return _POSIX_REALTIME_SIGNALS;
261 case _SC_SEMAPHORES: return _POSIX_SEMAPHORES;
262 case _SC_SHARED_MEMORY_OBJECTS: return _POSIX_SHARED_MEMORY_OBJECTS;
263 case _SC_SYNCHRONIZED_IO: return _POSIX_SYNCHRONIZED_IO;
264 case _SC_TIMERS: return _POSIX_TIMERS;
265 case _SC_GETGR_R_SIZE_MAX: return 1024;
266 case _SC_GETPW_R_SIZE_MAX: return 1024;
267 case _SC_LOGIN_NAME_MAX: return LOGIN_NAME_MAX;
268 case _SC_THREAD_DESTRUCTOR_ITERATIONS: return PTHREAD_DESTRUCTOR_ITERATIONS;
269 case _SC_THREAD_KEYS_MAX: return PTHREAD_KEYS_MAX;
270 case _SC_THREAD_STACK_MIN: return PTHREAD_STACK_MIN;
271 case _SC_THREAD_THREADS_MAX: return -1; // No specific limit.
272 case _SC_TTY_NAME_MAX: return TTY_NAME_MAX;
273 case _SC_THREADS: return _POSIX_THREADS;
274 case _SC_THREAD_ATTR_STACKADDR: return _POSIX_THREAD_ATTR_STACKADDR;
275 case _SC_THREAD_ATTR_STACKSIZE: return _POSIX_THREAD_ATTR_STACKSIZE;
276 case _SC_THREAD_PRIORITY_SCHEDULING: return _POSIX_THREAD_PRIORITY_SCHEDULING;
277 case _SC_THREAD_PRIO_INHERIT: return _POSIX_THREAD_PRIO_INHERIT;
278 case _SC_THREAD_PRIO_PROTECT: return _POSIX_THREAD_PRIO_PROTECT;
279 case _SC_THREAD_SAFE_FUNCTIONS: return _POSIX_THREAD_SAFE_FUNCTIONS;
280 case _SC_MONOTONIC_CLOCK: return _POSIX_MONOTONIC_CLOCK;
281
282 case _SC_2_PBS: return -1; // Obsolescent in POSIX.1-2008.
283 case _SC_2_PBS_ACCOUNTING: return -1; // Obsolescent in POSIX.1-2008.
284 case _SC_2_PBS_CHECKPOINT: return -1; // Obsolescent in POSIX.1-2008.
285 case _SC_2_PBS_LOCATE: return -1; // Obsolescent in POSIX.1-2008.
286 case _SC_2_PBS_MESSAGE: return -1; // Obsolescent in POSIX.1-2008.
287 case _SC_2_PBS_TRACK: return -1; // Obsolescent in POSIX.1-2008.
288 case _SC_ADVISORY_INFO: return _POSIX_ADVISORY_INFO;
289 case _SC_BARRIERS: return _POSIX_BARRIERS;
290 case _SC_CLOCK_SELECTION: return _POSIX_CLOCK_SELECTION;
291 case _SC_CPUTIME: return _POSIX_CPUTIME;
292
293 case _SC_HOST_NAME_MAX: return _POSIX_HOST_NAME_MAX; // Minimum requirement.
294 case _SC_IPV6: return _POSIX_IPV6;
295 case _SC_RAW_SOCKETS: return _POSIX_RAW_SOCKETS;
296 case _SC_READER_WRITER_LOCKS: return _POSIX_READER_WRITER_LOCKS;
297 case _SC_REGEXP: return _POSIX_REGEXP;
298 case _SC_SHELL: return _POSIX_SHELL;
299 case _SC_SPAWN: return _POSIX_SPAWN;
300 case _SC_SPIN_LOCKS: return _POSIX_SPIN_LOCKS;
301 case _SC_SPORADIC_SERVER: return _POSIX_SPORADIC_SERVER;
302 case _SC_SS_REPL_MAX: return -1;
303 case _SC_SYMLOOP_MAX: return _POSIX_SYMLOOP_MAX; // Minimum requirement.
304 case _SC_THREAD_CPUTIME: return _POSIX_THREAD_CPUTIME;
305
306 case _SC_THREAD_PROCESS_SHARED: return _POSIX_THREAD_PROCESS_SHARED;
307 case _SC_THREAD_ROBUST_PRIO_INHERIT: return _POSIX_THREAD_ROBUST_PRIO_INHERIT;
308 case _SC_THREAD_ROBUST_PRIO_PROTECT: return _POSIX_THREAD_ROBUST_PRIO_PROTECT;
309 case _SC_THREAD_SPORADIC_SERVER: return _POSIX_THREAD_SPORADIC_SERVER;
310 case _SC_TIMEOUTS: return _POSIX_TIMEOUTS;
311 case _SC_TRACE: return -1;
312 case _SC_TRACE_EVENT_FILTER: return -1;
313 case _SC_TRACE_EVENT_NAME_MAX: return -1;
314 case _SC_TRACE_INHERIT: return -1;
315 case _SC_TRACE_LOG: return -1;
316 case _SC_TRACE_NAME_MAX: return -1;
317 case _SC_TRACE_SYS_MAX: return -1;
318 case _SC_TRACE_USER_EVENT_MAX: return -1;
319 case _SC_TYPED_MEMORY_OBJECTS: return _POSIX_TYPED_MEMORY_OBJECTS;
320 case _SC_V7_ILP32_OFF32: return _POSIX_V7_ILP32_OFF32;
321 case _SC_V7_ILP32_OFFBIG: return _POSIX_V7_ILP32_OFFBIG;
322 case _SC_V7_LP64_OFF64: return _POSIX_V7_LP64_OFF64;
323 case _SC_V7_LPBIG_OFFBIG: return _POSIX_V7_LPBIG_OFFBIG;
324 case _SC_XOPEN_STREAMS: return -1;
325 case _SC_XOPEN_UUCP: return -1;
326
327 case _SC_LEVEL1_ICACHE_SIZE: return __sysconf_caches()->l1_i.size;
328 case _SC_LEVEL1_ICACHE_ASSOC: return __sysconf_caches()->l1_i.assoc;
329 case _SC_LEVEL1_ICACHE_LINESIZE: return __sysconf_caches()->l1_i.linesize;
330 case _SC_LEVEL1_DCACHE_SIZE: return __sysconf_caches()->l1_d.size;
331 case _SC_LEVEL1_DCACHE_ASSOC: return __sysconf_caches()->l1_d.assoc;
332 case _SC_LEVEL1_DCACHE_LINESIZE: return __sysconf_caches()->l1_d.linesize;
333 case _SC_LEVEL2_CACHE_SIZE: return __sysconf_caches()->l2.size;
334 case _SC_LEVEL2_CACHE_ASSOC: return __sysconf_caches()->l2.assoc;
335 case _SC_LEVEL2_CACHE_LINESIZE: return __sysconf_caches()->l2.linesize;
336 case _SC_LEVEL3_CACHE_SIZE: return __sysconf_caches()->l3.size;
337 case _SC_LEVEL3_CACHE_ASSOC: return __sysconf_caches()->l3.assoc;
338 case _SC_LEVEL3_CACHE_LINESIZE: return __sysconf_caches()->l3.linesize;
339 case _SC_LEVEL4_CACHE_SIZE: return __sysconf_caches()->l4.size;
340 case _SC_LEVEL4_CACHE_ASSOC: return __sysconf_caches()->l4.assoc;
341 case _SC_LEVEL4_CACHE_LINESIZE: return __sysconf_caches()->l4.linesize;
342
343 default:
344 errno = EINVAL;
345 return -1;
346 }
347 }
348