/* * 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 #include #include #include #include // For FOPEN_MAX. #include #include #include #include #include #include #include "private/bionic_tls.h" static long __sysconf_rlimit(int resource) { rlimit rl; getrlimit(resource, &rl); return rl.rlim_cur; } long sysconf(int name) { switch (name) { // // Things we actually have to calculate... // case _SC_ARG_MAX: // You might think that just returning a constant 128KiB (ARG_MAX) would // make sense, as this guy did: // // https://lkml.org/lkml/2017/11/15/813... // // I suspect a 128kB sysconf(_SC_ARG_MAX) is the sanest bet, simply // because of that "conservative is better than aggressive". // // Especially since _technically_ we're still limiting things to that // 128kB due to the single-string limit. // // Linus // // In practice that caused us trouble with toybox tests for xargs edge // cases. The tests assume that they can at least reach the kernel's // "minimum maximum" of 128KiB, but if we report 128KiB for _SC_ARG_MAX // and xargs starts subtracting the environment space and so on from that, // then xargs will think it's run out of space when given 128KiB of data, // which should always work. See this thread for more: // // http://lists.landley.net/pipermail/toybox-landley.net/2019-November/011229.html // // So let's resign ourselves to tracking what the kernel actually does. // Right now (2019, Linux 5.3) that amounts to: return MAX(MIN(__sysconf_rlimit(RLIMIT_STACK) / 4, 3 * _STK_LIM / 4), ARG_MAX); case _SC_AVPHYS_PAGES: return get_avphys_pages(); case _SC_CHILD_MAX: return __sysconf_rlimit(RLIMIT_NPROC); case _SC_CLK_TCK: return static_cast(getauxval(AT_CLKTCK)); case _SC_NPROCESSORS_CONF: return get_nprocs_conf(); case _SC_NPROCESSORS_ONLN: return get_nprocs(); case _SC_OPEN_MAX: return __sysconf_rlimit(RLIMIT_NOFILE); case _SC_PAGESIZE: case _SC_PAGE_SIZE: // _SC_PAGESIZE and _SC_PAGE_SIZE are distinct, but return the same value. return static_cast(getauxval(AT_PAGESZ)); case _SC_PHYS_PAGES: return get_phys_pages(); // // Constants... // case _SC_BC_BASE_MAX: return _POSIX2_BC_BASE_MAX; // Minimum requirement. case _SC_BC_DIM_MAX: return _POSIX2_BC_DIM_MAX; // Minimum requirement. case _SC_BC_SCALE_MAX: return _POSIX2_BC_SCALE_MAX; // Minimum requirement. case _SC_BC_STRING_MAX: return _POSIX2_BC_STRING_MAX; // Minimum requirement. case _SC_COLL_WEIGHTS_MAX: return _POSIX2_COLL_WEIGHTS_MAX; // Minimum requirement. case _SC_EXPR_NEST_MAX: return _POSIX2_EXPR_NEST_MAX; // Minimum requirement. case _SC_LINE_MAX: return _POSIX2_LINE_MAX; // Minimum requirement. case _SC_NGROUPS_MAX: return NGROUPS_MAX; case _SC_PASS_MAX: return PASS_MAX; case _SC_2_C_BIND: return _POSIX2_C_BIND; case _SC_2_C_DEV: return _POSIX2_C_DEV; case _SC_2_CHAR_TERM: return _POSIX2_CHAR_TERM; case _SC_2_FORT_DEV: return -1; case _SC_2_FORT_RUN: return -1; case _SC_2_LOCALEDEF: return _POSIX2_LOCALEDEF; case _SC_2_SW_DEV: return _POSIX2_SW_DEV; case _SC_2_UPE: return _POSIX2_UPE; case _SC_2_VERSION: return _POSIX2_VERSION; case _SC_JOB_CONTROL: return _POSIX_JOB_CONTROL; case _SC_SAVED_IDS: return _POSIX_SAVED_IDS; case _SC_VERSION: return _POSIX_VERSION; case _SC_RE_DUP_MAX: return _POSIX_RE_DUP_MAX; // Minimum requirement. case _SC_STREAM_MAX: return FOPEN_MAX; case _SC_TZNAME_MAX: return _POSIX_TZNAME_MAX; // Minimum requirement. case _SC_XOPEN_CRYPT: return _XOPEN_CRYPT; case _SC_XOPEN_ENH_I18N: return _XOPEN_ENH_I18N; case _SC_XOPEN_SHM: return _XOPEN_SHM; case _SC_XOPEN_VERSION: return _XOPEN_VERSION; case _SC_XOPEN_REALTIME: return _XOPEN_REALTIME; case _SC_XOPEN_REALTIME_THREADS: return _XOPEN_REALTIME_THREADS; case _SC_XOPEN_LEGACY: return _XOPEN_LEGACY; case _SC_ATEXIT_MAX: return LONG_MAX; // Unlimited. case _SC_IOV_MAX: return IOV_MAX; case _SC_XOPEN_UNIX: return _XOPEN_UNIX; case _SC_AIO_LISTIO_MAX: return _POSIX_AIO_LISTIO_MAX; // Minimum requirement. case _SC_AIO_MAX: return _POSIX_AIO_MAX; // Minimum requirement. case _SC_AIO_PRIO_DELTA_MAX:return 0; // Minimum requirement. case _SC_DELAYTIMER_MAX: return INT_MAX; case _SC_MQ_OPEN_MAX: return _POSIX_MQ_OPEN_MAX; // Minimum requirement. case _SC_MQ_PRIO_MAX: return _POSIX_MQ_PRIO_MAX; // Minimum requirement. case _SC_RTSIG_MAX: return RTSIG_MAX; case _SC_SEM_NSEMS_MAX: return _POSIX_SEM_NSEMS_MAX; // Minimum requirement. case _SC_SEM_VALUE_MAX: return SEM_VALUE_MAX; case _SC_SIGQUEUE_MAX: return _POSIX_SIGQUEUE_MAX; // Minimum requirement. case _SC_TIMER_MAX: return _POSIX_TIMER_MAX; // Minimum requirement. case _SC_ASYNCHRONOUS_IO: return _POSIX_ASYNCHRONOUS_IO; case _SC_FSYNC: return _POSIX_FSYNC; case _SC_MAPPED_FILES: return _POSIX_MAPPED_FILES; case _SC_MEMLOCK: return _POSIX_MEMLOCK; case _SC_MEMLOCK_RANGE: return _POSIX_MEMLOCK_RANGE; case _SC_MEMORY_PROTECTION: return _POSIX_MEMORY_PROTECTION; case _SC_MESSAGE_PASSING: return _POSIX_MESSAGE_PASSING; case _SC_PRIORITIZED_IO: return _POSIX_PRIORITIZED_IO; case _SC_PRIORITY_SCHEDULING: return _POSIX_PRIORITY_SCHEDULING; case _SC_REALTIME_SIGNALS: return _POSIX_REALTIME_SIGNALS; case _SC_SEMAPHORES: return _POSIX_SEMAPHORES; case _SC_SHARED_MEMORY_OBJECTS: return _POSIX_SHARED_MEMORY_OBJECTS; case _SC_SYNCHRONIZED_IO: return _POSIX_SYNCHRONIZED_IO; case _SC_TIMERS: return _POSIX_TIMERS; case _SC_GETGR_R_SIZE_MAX: return 1024; case _SC_GETPW_R_SIZE_MAX: return 1024; case _SC_LOGIN_NAME_MAX: return LOGIN_NAME_MAX; case _SC_THREAD_DESTRUCTOR_ITERATIONS: return PTHREAD_DESTRUCTOR_ITERATIONS; case _SC_THREAD_KEYS_MAX: return PTHREAD_KEYS_MAX; case _SC_THREAD_STACK_MIN: return PTHREAD_STACK_MIN; case _SC_THREAD_THREADS_MAX: return -1; // No specific limit. case _SC_TTY_NAME_MAX: return TTY_NAME_MAX; case _SC_THREADS: return _POSIX_THREADS; case _SC_THREAD_ATTR_STACKADDR: return _POSIX_THREAD_ATTR_STACKADDR; case _SC_THREAD_ATTR_STACKSIZE: return _POSIX_THREAD_ATTR_STACKSIZE; case _SC_THREAD_PRIORITY_SCHEDULING: return _POSIX_THREAD_PRIORITY_SCHEDULING; case _SC_THREAD_PRIO_INHERIT: return _POSIX_THREAD_PRIO_INHERIT; case _SC_THREAD_PRIO_PROTECT: return _POSIX_THREAD_PRIO_PROTECT; case _SC_THREAD_SAFE_FUNCTIONS: return _POSIX_THREAD_SAFE_FUNCTIONS; case _SC_MONOTONIC_CLOCK: return _POSIX_MONOTONIC_CLOCK; case _SC_2_PBS: return -1; // Obsolescent in POSIX.1-2008. case _SC_2_PBS_ACCOUNTING: return -1; // Obsolescent in POSIX.1-2008. case _SC_2_PBS_CHECKPOINT: return -1; // Obsolescent in POSIX.1-2008. case _SC_2_PBS_LOCATE: return -1; // Obsolescent in POSIX.1-2008. case _SC_2_PBS_MESSAGE: return -1; // Obsolescent in POSIX.1-2008. case _SC_2_PBS_TRACK: return -1; // Obsolescent in POSIX.1-2008. case _SC_ADVISORY_INFO: return _POSIX_ADVISORY_INFO; case _SC_BARRIERS: return _POSIX_BARRIERS; case _SC_CLOCK_SELECTION: return _POSIX_CLOCK_SELECTION; case _SC_CPUTIME: return _POSIX_CPUTIME; case _SC_HOST_NAME_MAX: return _POSIX_HOST_NAME_MAX; // Minimum requirement. case _SC_IPV6: return _POSIX_IPV6; case _SC_RAW_SOCKETS: return _POSIX_RAW_SOCKETS; case _SC_READER_WRITER_LOCKS: return _POSIX_READER_WRITER_LOCKS; case _SC_REGEXP: return _POSIX_REGEXP; case _SC_SHELL: return _POSIX_SHELL; case _SC_SPAWN: return _POSIX_SPAWN; case _SC_SPIN_LOCKS: return _POSIX_SPIN_LOCKS; case _SC_SPORADIC_SERVER: return _POSIX_SPORADIC_SERVER; case _SC_SS_REPL_MAX: return -1; case _SC_SYMLOOP_MAX: return _POSIX_SYMLOOP_MAX; // Minimum requirement. case _SC_THREAD_CPUTIME: return _POSIX_THREAD_CPUTIME; case _SC_THREAD_PROCESS_SHARED: return _POSIX_THREAD_PROCESS_SHARED; case _SC_THREAD_ROBUST_PRIO_INHERIT: return _POSIX_THREAD_ROBUST_PRIO_INHERIT; case _SC_THREAD_ROBUST_PRIO_PROTECT: return _POSIX_THREAD_ROBUST_PRIO_PROTECT; case _SC_THREAD_SPORADIC_SERVER: return _POSIX_THREAD_SPORADIC_SERVER; case _SC_TIMEOUTS: return _POSIX_TIMEOUTS; case _SC_TRACE: return -1; // Obsolescent in POSIX.1-2008. case _SC_TRACE_EVENT_FILTER: return -1; // Obsolescent in POSIX.1-2008. case _SC_TRACE_EVENT_NAME_MAX: return -1; case _SC_TRACE_INHERIT: return -1; // Obsolescent in POSIX.1-2008. case _SC_TRACE_LOG: return -1; // Obsolescent in POSIX.1-2008. case _SC_TRACE_NAME_MAX: return -1; case _SC_TRACE_SYS_MAX: return -1; case _SC_TRACE_USER_EVENT_MAX: return -1; case _SC_TYPED_MEMORY_OBJECTS: return _POSIX_TYPED_MEMORY_OBJECTS; case _SC_V7_ILP32_OFF32: return _POSIX_V7_ILP32_OFF32; case _SC_V7_ILP32_OFFBIG: return _POSIX_V7_ILP32_OFFBIG; case _SC_V7_LP64_OFF64: return _POSIX_V7_LP64_OFF64; case _SC_V7_LPBIG_OFFBIG: return _POSIX_V7_LPBIG_OFFBIG; case _SC_XOPEN_STREAMS: return -1; // Obsolescent in POSIX.1-2008. case _SC_XOPEN_UUCP: return -1; // We do not have actual implementations for cache queries. // It's valid to return 0 as the result is unknown. case _SC_LEVEL1_ICACHE_SIZE: return 0; case _SC_LEVEL1_ICACHE_ASSOC: return 0; case _SC_LEVEL1_ICACHE_LINESIZE: return 0; case _SC_LEVEL1_DCACHE_SIZE: return 0; case _SC_LEVEL1_DCACHE_ASSOC: return 0; case _SC_LEVEL1_DCACHE_LINESIZE: return 0; case _SC_LEVEL2_CACHE_SIZE: return 0; case _SC_LEVEL2_CACHE_ASSOC: return 0; case _SC_LEVEL2_CACHE_LINESIZE: return 0; case _SC_LEVEL3_CACHE_SIZE: return 0; case _SC_LEVEL3_CACHE_ASSOC: return 0; case _SC_LEVEL3_CACHE_LINESIZE: return 0; case _SC_LEVEL4_CACHE_SIZE: return 0; case _SC_LEVEL4_CACHE_ASSOC: return 0; case _SC_LEVEL4_CACHE_LINESIZE: return 0; default: errno = EINVAL; return -1; } }