2004-11-03 13:51:07 +00:00
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.\" Copyright (c) 1997 John S. Kallal (kallal@voicenet.com)
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.\"
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MB_CUR_MAX.3, MB_LEN_MAX.3, btowc.3, fgetwc.3, fgetws.3, fputwc.3, fputws.3, fwide.3, getwchar.3, iconv.3, iconv_close.3, iconv_open.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, nl_langinfo.3, putwchar.3, stpncpy.3, strnlen.3, towctrans.3, towlower.3, towupper.3, ungetwc.3, wcpcpy.3, wcpncpy.3, wcrtomb.3, wcscasecmp.3, wcscat.3, wcschr.3, wcscmp.3, wcscpy.3, wcscspn.3, wcsdup.3, wcslen.3, wcsncasecmp.3, wcsncat.3, wcsncmp.3, wcsncpy.3, wcsnlen.3, wcsnrtombs.3, wcspbrk.3, wcsrchr.3, wcsrtombs.3, wcsspn.3, wcsstr.3, wcstok.3, wcstombs.3, wcswidth.3, wctob.3, wctomb.3, wctrans.3, wctype.3, wcwidth.3, wmemchr.3, wmemcmp.3, wmemcpy.3, wmemmove.3, wmemset.3, wprintf.3, console.4, console_codes.4, random.4, charsets.7: s/GPLv2+_ONEPARA_DOC/GPLv2+_DOC_ONEPARA/
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-03-10 09:29:44 +00:00
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.\" %%%LICENSE_START(GPLv2+_DOC_ONEPARA)
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2004-11-03 13:51:07 +00:00
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.\" This is free documentation; you can redistribute it and/or
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.\" modify it under the terms of the GNU General Public License as
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.\" published by the Free Software Foundation; either version 2 of
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.\" the License, or (at your option) any later version.
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2013-03-10 09:28:56 +00:00
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.\" %%%LICENSE_END
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2004-11-03 13:51:07 +00:00
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.\"
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.\" Some changes by tytso and aeb.
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.\"
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2004-12-16 14:24:00 +00:00
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.\" 2004-12-16, John V. Belmonte/mtk, Updated init and quit scripts
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2005-04-18 13:35:29 +00:00
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.\" 2004-04-08, AEB, Improved description of read from /dev/urandom
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2008-06-18 10:26:36 +00:00
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.\" 2008-06-20, George Spelvin <linux@horizon.com>,
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.\" Matt Mackall <mpm@selenic.com>
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2004-12-16 14:24:00 +00:00
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.\"
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getent.1, ldd.1, locale.1, localedef.1, memusage.1, memusagestat.1, mtrace.1, _exit.2, _syscall.2, accept.2, access.2, acct.2, add_key.2, adjtimex.2, alloc_hugepages.2, arch_prctl.2, bdflush.2, bind.2, bpf.2, brk.2, cacheflush.2, capget.2, chdir.2, chmod.2, chown.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, close_range.2, connect.2, copy_file_range.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, fanotify_init.2, fanotify_mark.2, fcntl.2, flock.2, fork.2, fsync.2, futex.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpid.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, getxattr.2, idle.2, init_module.2, inotify_add_watch.2, inotify_rm_watch.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl.2, ioctl_console.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_fslabel.2, ioctl_getfsmap.2, ioctl_ns.2, ioctl_tty.2, ioctl_userfaultfd.2, ioperm.2, iopl.2, ipc.2, kcmp.2, kexec_load.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, mount.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open.2, open_by_handle_at.2, openat2.2, pause.2, pciconfig_read.2, perf_event_open.2, perfmonctl.2, personality.2, pidfd_getfd.2, pidfd_open.2, pidfd_send_signal.2, pipe.2, pivot_root.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readlink.2, readv.2, reboot.2, recv.2, remap_file_pages.2, removexattr.2, rename.2, request_key.2, restart_syscall.2, rmdir.2, rt_sigqueueinfo.2, s390_guarded_storage.2, s390_pci_mmio_write.2, s390_runtime_instr.2, s390_sthyi.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setattr.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, seccomp.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, set_thread_area.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, setup.2, setxattr.2, sgetmask.2, shmctl.2, shmget.2, shmop.2, shutdown.2, sigaction.2, sigaltstack.2, signal.2, signalfd.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, spu_create.2, spu_run.2, stat.2, statfs.2, statx.2, stime.2, subpage_prot.2, swapon.2, symlink.2, sync.2, sync_file_range.2, syscall.2, syscalls.2, sysctl.2, sysfs.2, sysinfo.2, syslog.2, time.2, timer_create.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, uname.2, unimplemented.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, ustat.2, utime.2, utimensat.2, vfork.2, vhangup.2, vm86.2, vmsplice.2, wait.2, wait4.2, write.2, CPU_SET.3, __ppc_get_timebase.3, __ppc_set_ppr_med.3, __ppc_yield.3, __setfpucw.3, a64l.3, abort.3, abs.3, acos.3, acosh.3, addseverity.3, adjtime.3, aio_cancel.3, aio_error.3, aio_fsync.3, aio_read.3, aio_return.3, aio_suspend.3, aio_write.3, alloca.3, argz_add.3, asin.3, asinh.3, asprintf.3, assert.3, assert_perror.3, atan.3, atan2.3, atanh.3, atexit.3, atof.3, atoi.3, backtrace.3, basename.3, bcmp.3, bcopy.3, bindresvport.3, bsd_signal.3, bsearch.3, bstring.3, btowc.3, byteorder.3, bzero.3, cabs.3, cacos.3, cacosh.3, canonicalize_file_name.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, catgets.3, catopen.3, cbrt.3, ccos.3, ccosh.3, ceil.3, cexp.3, cexp2.3, cfree.3, cimag.3, circleq.3, clearenv.3, clock.3, clock_getcpuclockid.3, clog.3, clog10.3, clog2.3, closedir.3, cmsg.3, confstr.3, conj.3, copysign.3, cos.3, cosh.3, cpow.3, cproj.3, creal.3, crypt.3, csin.3, csinh.3, csqrt.3, ctan.3, ctanh.3, ctermid.3, ctime.3, daemon.3, des_crypt.3, difftime.3, dirfd.3, div.3, dl_iterate_phdr.3, dladdr.3, dlerror.3, dlinfo.3, dlopen.3, dlsym.3, drand48.3, drand48_r.3, duplocale.3, dysize.3, ecvt.3, ecvt_r.3, encrypt.3, endian.3, envz_add.3, erf.3, erfc.3, err.3, errno.3, error.3, ether_aton.3, euidaccess.3, exec.3, exit.3, exp.3, exp10.3, exp2.3, expm1.3, fabs.3, fclose.3, fcloseall.3, fdim.3, fenv.3, ferror.3, fexecve.3, fflush.3, ffs.3, fgetc.3, fgetgrent.3, fgetpwent.3, fgetwc.3, fgetws.3, fileno.3, finite.3, flockfile.3, floor.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmod.3, fmtmsg.3, fnmatch.3, fopen.3, fopencookie.3, fpathconf.3, fpclassify.3, fpurge.3, fputwc.3, fputws.3, fread.3, frexp.3, fseek.3, fseeko.3, ftime.3, ftok.3, fts.3, ftw.3, futimes.3, fwide.3, gamma.3, gcvt.3, get_nprocs_conf.3, get_phys_pages.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getentropy.3, getenv.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getifaddrs.3, getipnodebyname.3, getline.3, getloadavg.3, getlogin.3, getmntent.3, getnameinfo.3, getnetent.3, getnetent_r.3, getopt.3, getpass.3, getprotoent.3, getprotoent_r.3, getpt.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent.3, getrpcent_r.3, getrpcport.3, gets.3, getservent.3, getservent_r.3, getspnam.3, getsubopt.3, getttyent.3, getumask.3, getusershell.3, getutent.3, getutmp.3, getw.3, getwchar.3, glob.3, gnu_get_libc_version.3, grantpt.3, group_member.3, gsignal.3, hsearch.3, hypot.3, iconv.3, iconv_close.3, iconv_open.3, if_nameindex.3, if_nametoindex.3, ilogb.3, index.3, inet.3, inet_net_pton.3, inet_ntop.3, inet_pton.3, initgroups.3, insque.3, isalpha.3, isatty.3, isfdtype.3, isgreater.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, j0.3, key_setsecret.3, killpg.3, ldexp.3, lgamma.3, lio_listio.3, list.3, localeconv.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, login.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, makedev.3, mallinfo.3, malloc.3, malloc_get_state.3, malloc_hook.3, malloc_info.3, malloc_stats.3, malloc_trim.3, malloc_usable_size.3, mallopt.3, matherr.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, mcheck.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, mempcpy.3, memset.3, mkdtemp.3, mkfifo.3, mkstemp.3, mktemp.3, modf.3, mpool.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_open.3, mq_receive.3, mq_send.3, mq_unlink.3, mtrace.3, nan.3, newlocale.3, nextafter.3, nextup.3, nl_langinfo.3, ntp_gettime.3, on_exit.3, open_memstream.3, opendir.3, openpty.3, perror.3, popen.3, posix_fallocate.3, posix_madvise.3, posix_memalign.3, posix_openpt.3, posix_spawn.3, pow.3, pow10.3, printf.3, profil.3, psignal.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setsigmask_np.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_detach.3, pthread_equal.3, pthread_exit.3, pthread_getattr_default_np.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_join.3, pthread_kill.3, pthread_kill_other_threads_np.3, pthread_mutex_consistent.3, pthread_mutexattr_getpshared.3, pthread_mutexattr_setrobust.3, pthread_rwlockattr_setkind_np.3, pthread_self.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_setschedprio.3, pthread_sigmask.3, pthread_sigqueue.3, pthread_spin_init.3, pthread_spin_lock.3, pthread_testcancel.3, pthread_tryjoin_np.3, pthread_yield.3, ptsname.3, putenv.3, putgrent.3, putpwent.3, puts.3, putwchar.3, qecvt.3, qsort.3, raise.3, rand.3, random.3, random_r.3, rcmd.3, re_comp.3, readdir.3, readdir_r.3, realpath.3, regex.3, remainder.3, remove.3, remquo.3, resolver.3, rewinddir.3, rexec.3, rint.3, round.3, rpc.3, rpmatch.3, rtime.3, rtnetlink.3, scalb.3, scalbln.3, scandir.3, scanf.3, sched_getcpu.3, seekdir.3, sem_close.3, sem_destroy.3, sem_getvalue.3, sem_init.3, sem_open.3, sem_post.3, sem_unlink.3, sem_wait.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, setlocale.3, setlogmask.3, setnetgrent.3, shm_open.3, siginterrupt.3, signbit.3, significand.3, sigpause.3, sigqueue.3, sigset.3, sigsetops.3, sigvec.3, sigwait.3, sin.3, sincos.3, sinh.3, sleep.3, slist.3, sockatmark.3, sqrt.3, stailq.3, statvfs.3, stdarg.3, stdio.3, stdio_ext.3, stpcpy.3, stpncpy.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strdup.3, strerror.3, strfmon.3, strfromd.3, strfry.3, strftime.3, string.3, strlen.3, strnlen.3, strpbrk.3, strptime.3, strsep.3, strsignal.3, strspn.3, strstr.3, strtod.3, strtoimax.3, strtok.3, strtol.3, strtoul.3, strverscmp.3, strxfrm.3, swab.3, sysconf.3, syslog.3, system.3, sysv_signal.3, tailq.3, tan.3, tanh.3, tcgetpgrp.3, tcgetsid.3, telldir.3, tempnam.3, termios.3, tgamma.3, timegm.3, timeradd.3, tmpfile.3, tmpnam.3, toascii.3, toupper.3, towctrans.3, towlower.3, towupper.3, trunc.3, tsearch.3, ttyname.3, ttyslot.3, tzset.3, ualarm.3, ulimit.3, undocumented.3, ungetwc.3, unlocked_stdio.3, unlockpt.3, updwtmp.3, uselocale.3, usleep.3, wcpcpy.3, wcpncpy.3, wcrtomb.3, wcscasecmp.3, wcscat.3, wcschr.3, wcscmp.3, wcscpy.3, wcscspn.3, wcsdup.3, wcslen.3, wcsncasecmp.3, wcsncat.3, wcsncmp.3, wcsncpy.3, wcsnlen.3, wcsnrtombs.3, wcspbrk.3, wcsrchr.3, wcsrtombs.3, wcsspn.3, wcsstr.3, wcstoimax.3, wcstok.3, wcstombs.3, wcswidth.3, wctob.3, wctomb.3, wctrans.3, wctype.3, wcwidth.3, wmemchr.3, wmemcmp.3, wmemcpy.3, wmemmove.3, wmemset.3, wordexp.3, wprintf.3, xcrypt.3, xdr.3, y0.3, cciss.4, console_codes.4, dsp56k.4, hpsa.4, initrd.4, loop.4, lp.4, msr.4, random.4, rtc.4, smartpqi.4, veth.4, wavelan.4, acct.5, core.5, elf.5, hosts.5, locale.5, proc.5, resolv.conf.5, rpc.5, slabinfo.5, sysfs.5, tmpfs.5, utmp.5, address_families.7, aio.7, attributes.7, bootparam.7, capabilities.7, cgroups.7, complex.7, ddp.7, environ.7, epoll.7, fanotify.7, feature_test_macros.7, hier.7, inode.7, inotify.7, ip.7, ipv6.7, keyrings.7, locale.7, man-pages.7, man.7, math_error.7, mount_namespaces.7, namespaces.7, netdevice.7, netlink.7, numa.7, packet.7, pkeys.7, pthreads.7, queue.7, raw.7, rtnetlink.7, sched.7, session-keyring.7, shm_overview.7, sigevent.7, signal-safety.7, signal.7, sock_diag.7, socket.7, spufs.7, symlink.7, system_data_types.7, tcp.7, time_namespaces.7, udp.7, udplite.7, unicode.7, unix.7, uri.7, user_namespaces.7, vdso.7, vsock.7, x25.7, iconvconfig.8, ld.so.8, ldconfig.8, sln.8, tzselect.8: tstamp
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2021-03-21 23:15:34 +00:00
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.TH RANDOM 4 2021-03-22 "Linux" "Linux Programmer's Manual"
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2004-11-03 13:51:07 +00:00
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.SH NAME
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random, urandom \- kernel random number source devices
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2013-03-14 10:20:18 +00:00
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.SH SYNOPSIS
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2021-01-03 11:49:03 +00:00
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.nf
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2013-03-14 10:20:18 +00:00
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#include <linux/random.h>
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_exit.2, bpf.2, cacheflush.2, capget.2, chdir.2, chmod.2, chroot.2, clock_getres.2, clock_nanosleep.2, close.2, connect.2, create_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, execveat.2, exit_group.2, fanotify_mark.2, flock.2, fork.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_mempolicy.2, get_robust_list.2, getcpu.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpid.2, getpriority.2, getrandom.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, getxattr.2, idle.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, ioctl.2, ioctl_fat.2, ioctl_ficlonerange.2, ioctl_fideduperange.2, ioctl_getfsmap.2, ioctl_tty.2, ioperm.2, iopl.2, keyctl.2, kill.2, link.2, listen.2, listxattr.2, llseek.2, lseek.2, madvise.2, mbind.2, membarrier.2, memfd_create.2, migrate_pages.2, mincore.2, mkdir.2, mknod.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, mount.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, pause.2, pciconfig_read.2, perf_event_open.2, perfmonctl.2, personality.2, pkey_alloc.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, read.2, readahead.2, readdir.2, readv.2, reboot.2, recv.2, remap_file_pages.2, removexattr.2, rename.2, request_key.2, rmdir.2, rt_sigqueueinfo.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, select.2, select_tut.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, set_mempolicy.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setns.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, setup.2, setxattr.2, sgetmask.2, shmctl.2, shmget.2, shutdown.2, sigaction.2, sigaltstack.2, sigpending.2, sigprocmask.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, stat.2, statfs.2, stime.2, swapon.2, symlink.2, sync.2, sysctl.2, sysinfo.2, syslog.2, time.2, timer_create.2, timer_delete.2, timer_getoverrun.2, timer_settime.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, uname.2, unlink.2, unshare.2, uselib.2, userfaultfd.2, ustat.2, utime.2, utimensat.2, vfork.2, vhangup.2, vm86.2, wait.2, wait4.2, write.2, CPU_SET.3, INFINITY.3, __ppc_get_timebase.3, __ppc_set_ppr_med.3, __ppc_yield.3, __setfpucw.3, a64l.3, abort.3, abs.3, acos.3, acosh.3, addseverity.3, adjtime.3, aio_cancel.3, aio_error.3, aio_fsync.3, aio_init.3, aio_read.3, aio_return.3, aio_suspend.3, aio_write.3, alloca.3, argz_add.3, asin.3, asinh.3, asprintf.3, assert.3, assert_perror.3, atan.3, atan2.3, atanh.3, atexit.3, atof.3, atoi.3, basename.3, bcmp.3, bcopy.3, bsd_signal.3, bsearch.3, bstring.3, btowc.3, byteorder.3, cabs.3, cacos.3, cacosh.3, canonicalize_file_name.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, catopen.3, cbrt.3, ccos.3, ccosh.3, ceil.3, cexp.3, cexp2.3, cfree.3, cimag.3, clearenv.3, clock.3, clock_getcpuclockid.3, clog.3, clog10.3, clog2.3, closedir.3, cmsg.3, confstr.3, conj.3, copysign.3, cos.3, cosh.3, cpow.3, cproj.3, creal.3, crypt.3, csin.3, csinh.3, csqrt.3, ctan.3, ctanh.3, ctermid.3, ctime.3, daemon.3, difftime.3, dirfd.3, div.3, dlerror.3, dlopen.3, dlsym.3, drand48.3, drand48_r.3, duplocale.3, dysize.3, ecvt.3, ecvt_r.3, encrypt.3, endian.3, erf.3, erfc.3, err.3, errno.3, ether_aton.3, euidaccess.3, exec.3, exit.3, exp.3, exp10.3, exp2.3, expm1.3, fabs.3, fclose.3, fcloseall.3, fdim.3, fenv.3, ferror.3, fexecve.3, fflush.3, ffs.3, fgetc.3, fgetgrent.3, fgetpwent.3, fgetwc.3, fgetws.3, finite.3, flockfile.3, floor.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmod.3, fmtmsg.3, fnmatch.3, fopen.3, fpathconf.3, fpclassify.3, fpurge.3, fputwc.3, fputws.3, fread.3, frexp.3, fseek.3, fseeko.3, ftime.3, ftok.3, fts.3, ftw.3, futimes.3, fwide.3, gamma.3, gcvt.3, get_nprocs_conf.3, get_phys_pages.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getentropy.3, getenv.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getifaddrs.3, getipnodebyname.3, getline.3, getloadavg.3, getlogin.3, getmntent.3, getnameinfo.3, getnetent.3, getnetent_r.3, getopt.3, getpass.3, getprotoent.3, getprotoent_r.3, getpt.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent_r.3, getrpcport.3, gets.3, getservent.3, getservent_r.3, getspnam.3, getsubopt.3, getttyent.3, getumask.3, getusershell.3, getutent.3, getw.3, getwchar.3, glob.3, grantpt.3, group_member.3, gsignal.3, hsearch.3, hypot.3, iconv.3, iconv_close.3, iconv_open.3, if_nameindex.3, if_nametoindex.3, ilogb.3, index.3, inet.3, inet_net_pton.3, inet_ntop.3, infnan.3, initgroups.3, insque.3, isalpha.3, isatty.3, isfdtype.3, isgreater.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, j0.3, key_setsecret.3, killpg.3, ldexp.3, lgamma.3, localeconv.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, login.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, malloc.3, malloc_get_state.3, malloc_hook.3, malloc_info.3, matherr.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, mcheck.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, mempcpy.3, memset.3, mkdtemp.3, mkfifo.3, mkstemp.3, mktemp.3, modf.3, mpool.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_open.3, mq_receive.3, mq_send.3, mq_unlink.3, mtrace.3, nan.3, netlink.3, newlocale.3, nextafter.3, nl_langinfo.3, offsetof.3, on_exit.3, open_memstream.3, opendir.3, openpty.3, perror.3, popen.3, posix_fallocate.3, posix_madvise.3, posix_memalign.3, posix_openpt.3, pow.3, pow10.3, printf.3, profil.3, psignal.3, pthread_atfork.3, pthread_attr_init.3, pthread_attr_setaffinity_np.3, pthread_attr_setdetachstate.3, pthread_attr_setguardsize.3, pthread_attr_setinheritsched.3, pthread_attr_setschedparam.3, pthread_attr_setschedpolicy.3, pthread_attr_setscope.3, pthread_attr_setstack.3, pthread_attr_setstackaddr.3, pthread_attr_setstacksize.3, pthread_cancel.3, pthread_cleanup_push.3, pthread_cleanup_push_defer_np.3, pthread_create.3, pthread_detach.3, pthread_equal.3, pthread_exit.3, pthread_getattr_default_np.3, pthread_getattr_np.3, pthread_getcpuclockid.3, pthread_join.3, pthread_kill.3, pthread_rwlockattr_setkind_np.3, pthread_self.3, pthread_setaffinity_np.3, pthread_setcancelstate.3, pthread_setconcurrency.3, pthread_setname_np.3, pthread_setschedparam.3, pthread_setschedprio.3, pthread_sigmask.3, pthread_sigqueue.3, pthread_testcancel.3, pthread_tryjoin_np.3, pthread_yield.3, ptsname.3, putenv.3, putgrent.3, putpwent.3, puts.3, putwchar.3, qecvt.3, qsort.3, raise.3, rand.3, random.3, random_r.3, rcmd.3, re_comp.3, readdir.3, realpath.3, remainder.3, remove.3, remquo.3, resolver.3, rewinddir.3, rexec.3, rint.3, round.3, rpmatch.3, rtime.3, rtnetlink.3, scalb.3, scalbln.3, scandir.3, scanf.3, sched_getcpu.3, seekdir.3, sem_close.3, sem_destroy.3, sem_getvalue.3, sem_init.3, sem_open.3, sem_post.3, sem_unlink.3, sem_wait.3, setaliasent.3, setbuf.3, setenv.3, setlocale.3, setlogmask.3, setnetgrent.3, shm_open.3, siginterrupt.3, signbit.3, significand.3, sigpause.3, sigqueue.3, sigset.3, sigvec.3, sigwait.3, sin.3, sincos.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stdarg.3, stdio.3, stdio_ext.3, stpcpy.3, stpncpy.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strdup.3, strerror.3, strfmon.3, strfromd.3, strfry.3, strftime.3, strlen.3, strnlen.3, strpbrk.3, strptime.3, strsep.3, strsignal.3, strspn.3, strstr.3, strtod.3, strtoimax.3, strtok.3, strtol.3, strtoul.3, strverscmp.3, strxfrm.3, swab.3, sysconf.3, syslog.3, system.3, sysv_signal.3, tan.3, tanh.3, tcgetpgrp.3, tcgetsid.3, telldir.3, tempnam.3, termios.3, tgamma.3, timegm.3, timeradd.3, tmpfile.3, tmpnam.3, toascii.3, toupper.3, towctrans.3, towlower.3, towupper.3, trunc.3, tsearch.3, ttyname.3, ttyslot.3, tzset.3, ualarm.3, ulimit.3, ungetwc.3, unlocked_stdio.3, unlockpt.3, updwtmp.3, uselocale.3, usleep.3, wcpcpy.3, wcpncpy.3, wcrtomb.3, wcscasecmp.3, wcscat.3, wcschr.3, wcscmp.3, wcscpy.3, wcscspn.3, wcsdup.3, wcslen.3, wcsncasecmp.3, wcsncat.3, wcsncmp.3, wcsncpy.3, wcsnlen.3, wcsnrtombs.3, wcspbrk.3, wcsrchr.3, wcsrtombs.3, wcsspn.3, wcsstr.3, wcstoimax.3, wcstok.3, wcstombs.3, wcswidth.3, wctob.3, wctomb.3, wctrans.3, wctype.3, wcwidth.3, wmemchr.3, wmemcmp.3, wmemcpy.3, wmemmove.3, wmemset.3, wordexp.3, wprintf.3, xcrypt.3, y0.3, dsp56k.4, random.4, rtc.4, st.4, ddp.7, ip.7, ipv6.7, packet.7, rtnetlink.7, socket.7, tcp.7, udp.7, udplite.7, x25.7: ffix
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-15 15:16:29 +00:00
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.PP
|
2013-03-14 10:20:18 +00:00
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|
.BI "int ioctl(" fd ", RND" request ", " param ");"
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2021-01-03 11:49:03 +00:00
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.fi
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2004-11-03 13:51:07 +00:00
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.SH DESCRIPTION
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2007-04-12 22:42:49 +00:00
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The character special files \fI/dev/random\fP and
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2005-11-02 13:55:25 +00:00
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\fI/dev/urandom\fP (present since Linux 1.3.30)
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2007-04-12 22:42:49 +00:00
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provide an interface to the kernel's random number generator.
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2016-11-10 11:40:39 +00:00
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The file
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2017-08-12 20:42:34 +00:00
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.I /dev/random
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2016-11-10 11:40:39 +00:00
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has major device number 1 and minor device number 8.
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The file
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.I /dev/urandom
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has major device number 1 and minor device number 9.
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getent.1, intro.1, time.1, _exit.2, alloc_hugepages.2, arch_prctl.2, clock_getres.2, getitimer.2, getrusage.2, intro.2, ioctl_console.2, ioctl_list.2, ioctl_tty.2, kill.2, madvise.2, mlock.2, mmap.2, mount.2, open.2, outb.2, perf_event_open.2, ptrace.2, quotactl.2, reboot.2, recv.2, remap_file_pages.2, select.2, semctl.2, send.2, set_tid_address.2, seteuid.2, shmop.2, statfs.2, times.2, truncate.2, uname.2, uselib.2, vm86.2, wait.2, a64l.3, aio_cancel.3, aio_fsync.3, aio_read.3, aio_return.3, aio_suspend.3, aio_write.3, alloca.3, argz_add.3, atexit.3, basename.3, bindresvport.3, cacos.3, cacosh.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, catgets.3, catopen.3, cexp.3, cfree.3, cimag.3, clog.3, conj.3, creal.3, ctime.3, des_crypt.3, dirfd.3, div.3, dlopen.3, envz_add.3, exit.3, fenv.3, flockfile.3, fmtmsg.3, fpclassify.3, fpurge.3, fseeko.3, ftime.3, ftok.3, ftw.3, getcontext.3, getcwd.3, getdate.3, getfsent.3, getgrent.3, getgrnam.3, gethostbyname.3, getipnodebyname.3, getlogin.3, getpwnam.3, getrpcent.3, getspnam.3, getutent.3, gsignal.3, hsearch.3, lockf.3, logb.3, login.3, lseek64.3, makecontext.3, malloc.3, malloc_hook.3, nan.3, nl_langinfo.3, openpty.3, posix_spawn.3, putenv.3, realpath.3, remainder.3, rint.3, rpc.3, rtime.3, scandir.3, setlogmask.3, shm_open.3, sigpause.3, statvfs.3, stdio_ext.3, strfmon.3, strftime.3, strptime.3, strtod.3, strtol.3, strtoul.3, swab.3, sysconf.3, syslog.3, tcgetpgrp.3, tempnam.3, termios.3, tmpfile.3, tmpnam.3, ttyslot.3, tzset.3, ualarm.3, usleep.3, wordexp.3, xcrypt.3, xdr.3, cciss.4, console_codes.4, full.4, hd.4, loop.4, mem.4, null.4, pts.4, ram.4, random.4, tty.4, ttyS.4, vcs.4, networks.5, nsswitch.conf.5, protocols.5, resolv.conf.5, slabinfo.5, termcap.5, ascii.7, boot.7, bootparam.7, charsets.7, icmp.7, inode.7, man.7, netdevice.7, posixoptions.7, ld.so.8: srcfix: use .PP instead of .LP
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-17 23:12:54 +00:00
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.PP
|
2007-04-12 22:42:49 +00:00
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|
The random number generator gathers environmental noise
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|
from device drivers and other sources into an entropy pool.
|
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|
The generator also keeps an estimate of the
|
2004-11-03 13:51:07 +00:00
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number of bits of noise in the entropy pool.
|
2016-11-10 11:39:56 +00:00
|
|
|
From this entropy pool, random numbers are created.
|
getent.1, intro.1, time.1, _exit.2, alloc_hugepages.2, arch_prctl.2, clock_getres.2, getitimer.2, getrusage.2, intro.2, ioctl_console.2, ioctl_list.2, ioctl_tty.2, kill.2, madvise.2, mlock.2, mmap.2, mount.2, open.2, outb.2, perf_event_open.2, ptrace.2, quotactl.2, reboot.2, recv.2, remap_file_pages.2, select.2, semctl.2, send.2, set_tid_address.2, seteuid.2, shmop.2, statfs.2, times.2, truncate.2, uname.2, uselib.2, vm86.2, wait.2, a64l.3, aio_cancel.3, aio_fsync.3, aio_read.3, aio_return.3, aio_suspend.3, aio_write.3, alloca.3, argz_add.3, atexit.3, basename.3, bindresvport.3, cacos.3, cacosh.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, catgets.3, catopen.3, cexp.3, cfree.3, cimag.3, clog.3, conj.3, creal.3, ctime.3, des_crypt.3, dirfd.3, div.3, dlopen.3, envz_add.3, exit.3, fenv.3, flockfile.3, fmtmsg.3, fpclassify.3, fpurge.3, fseeko.3, ftime.3, ftok.3, ftw.3, getcontext.3, getcwd.3, getdate.3, getfsent.3, getgrent.3, getgrnam.3, gethostbyname.3, getipnodebyname.3, getlogin.3, getpwnam.3, getrpcent.3, getspnam.3, getutent.3, gsignal.3, hsearch.3, lockf.3, logb.3, login.3, lseek64.3, makecontext.3, malloc.3, malloc_hook.3, nan.3, nl_langinfo.3, openpty.3, posix_spawn.3, putenv.3, realpath.3, remainder.3, rint.3, rpc.3, rtime.3, scandir.3, setlogmask.3, shm_open.3, sigpause.3, statvfs.3, stdio_ext.3, strfmon.3, strftime.3, strptime.3, strtod.3, strtol.3, strtoul.3, swab.3, sysconf.3, syslog.3, tcgetpgrp.3, tempnam.3, termios.3, tmpfile.3, tmpnam.3, ttyslot.3, tzset.3, ualarm.3, usleep.3, wordexp.3, xcrypt.3, xdr.3, cciss.4, console_codes.4, full.4, hd.4, loop.4, mem.4, null.4, pts.4, ram.4, random.4, tty.4, ttyS.4, vcs.4, networks.5, nsswitch.conf.5, protocols.5, resolv.conf.5, slabinfo.5, termcap.5, ascii.7, boot.7, bootparam.7, charsets.7, icmp.7, inode.7, man.7, netdevice.7, posixoptions.7, ld.so.8: srcfix: use .PP instead of .LP
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-17 23:12:54 +00:00
|
|
|
.PP
|
2016-11-11 09:41:41 +00:00
|
|
|
Linux 3.17 and later provides the simpler and safer
|
2016-11-10 11:38:58 +00:00
|
|
|
.BR getrandom (2)
|
2016-11-11 09:41:41 +00:00
|
|
|
interface which requires no special files;
|
|
|
|
see the
|
|
|
|
.BR getrandom (2)
|
|
|
|
manual page for details.
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2016-11-10 11:38:58 +00:00
|
|
|
When read, the
|
|
|
|
.I /dev/urandom
|
|
|
|
device returns random bytes using a pseudorandom
|
|
|
|
number generator seeded from the entropy pool.
|
2016-11-11 12:26:02 +00:00
|
|
|
Reads from this device do not block (i.e., the CPU is not yielded),
|
2016-11-12 10:51:22 +00:00
|
|
|
but can incur an appreciable delay when requesting large amounts of data.
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2016-11-11 11:46:29 +00:00
|
|
|
When read during early boot time,
|
2016-11-15 06:05:53 +00:00
|
|
|
.IR /dev/urandom
|
2016-11-11 11:46:29 +00:00
|
|
|
may return data prior to the entropy pool being initialized.
|
2016-11-12 10:56:18 +00:00
|
|
|
.\" This is a real problem; see
|
|
|
|
.\" commit 9b4d008787f864f17d008c9c15bbe8a0f7e2fc24
|
2016-11-10 08:54:27 +00:00
|
|
|
If this is of concern in your application, use
|
2016-11-10 11:38:58 +00:00
|
|
|
.BR getrandom (2)
|
2016-11-10 08:54:27 +00:00
|
|
|
or \fI/dev/random\fP instead.
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2016-11-10 08:54:27 +00:00
|
|
|
The \fI/dev/random\fP device is a legacy interface which dates back to
|
|
|
|
a time where the cryptographic primitives used in the implementation
|
2016-11-10 11:38:58 +00:00
|
|
|
of \fI/dev/urandom\fP were not widely trusted.
|
|
|
|
It will return random bytes only within the estimated number of
|
|
|
|
bits of fresh noise in the entropy pool, blocking if necessary.
|
2016-11-12 10:00:12 +00:00
|
|
|
\fI/dev/random\fP is suitable for applications that need
|
2016-11-10 08:54:27 +00:00
|
|
|
high quality randomness, and can afford indeterminate delays.
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2007-04-12 22:42:49 +00:00
|
|
|
When the entropy pool is empty, reads from \fI/dev/random\fP will block
|
2004-11-03 13:51:07 +00:00
|
|
|
until additional environmental noise is gathered.
|
2014-11-26 22:56:05 +00:00
|
|
|
If
|
|
|
|
.BR open (2)
|
|
|
|
is called for
|
|
|
|
.I /dev/random
|
2016-11-11 09:41:41 +00:00
|
|
|
with the
|
|
|
|
.BR O_NONBLOCK
|
|
|
|
flag, a subsequent
|
2014-11-26 22:56:05 +00:00
|
|
|
.BR read (2)
|
|
|
|
will not block if the requested number of bytes is not available.
|
2015-01-10 13:55:57 +00:00
|
|
|
Instead, the available bytes are returned.
|
2015-02-04 08:48:39 +00:00
|
|
|
If no byte is available,
|
2014-11-26 22:56:05 +00:00
|
|
|
.BR read (2)
|
2021-01-09 21:08:50 +00:00
|
|
|
will return \-1 and
|
2014-11-26 22:56:05 +00:00
|
|
|
.I errno
|
|
|
|
will be set to
|
|
|
|
.BR EAGAIN .
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2016-11-11 09:41:41 +00:00
|
|
|
The
|
2014-11-26 22:56:05 +00:00
|
|
|
.B O_NONBLOCK
|
2016-11-11 09:41:41 +00:00
|
|
|
flag has no effect when opening
|
2014-11-26 22:56:05 +00:00
|
|
|
.IR /dev/urandom .
|
|
|
|
When calling
|
|
|
|
.BR read (2)
|
2015-02-04 08:48:39 +00:00
|
|
|
for the device
|
|
|
|
.IR /dev/urandom ,
|
2016-11-10 13:37:33 +00:00
|
|
|
reads of up to 256 bytes will return as many bytes as are requested
|
|
|
|
and will not be interrupted by a signal handler.
|
|
|
|
Reads with a buffer over this limit may return less than the
|
|
|
|
requested number of bytes or fail with the error
|
2016-11-10 19:51:54 +00:00
|
|
|
.BR EINTR ,
|
|
|
|
if interrupted by a signal handler.
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2015-02-04 09:16:43 +00:00
|
|
|
Since Linux 3.16,
|
|
|
|
.\" commit 79a8468747c5f95ed3d5ce8376a3e82e0c5857fc
|
|
|
|
a
|
|
|
|
.BR read (2)
|
|
|
|
from
|
|
|
|
.IR /dev/urandom
|
add_key.2, alloc_hugepages.2, execve.2, fanotify_init.2, getrlimit.2, listxattr.2, mmap.2, shmget.2, malloc.3, random.4, st.4, bootparam.7, epoll.7, keyrings.7, pipe.7, xattr.7: Use non-breaking space for measurement units
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2017-08-18 10:28:20 +00:00
|
|
|
will return at most 32\ MB.
|
2015-02-04 09:25:33 +00:00
|
|
|
A
|
|
|
|
.BR read (2)
|
|
|
|
from
|
|
|
|
.IR /dev/random
|
|
|
|
will return at most 512 bytes
|
|
|
|
.\" SEC_XFER_SIZE in drivers/char/random.c
|
|
|
|
(340 bytes on Linux kernels before version 2.6.12).
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2013-03-14 10:20:18 +00:00
|
|
|
Writing to \fI/dev/random\fP or \fI/dev/urandom\fP will update the
|
|
|
|
entropy pool with the data written, but this will not result in a
|
2013-03-14 10:29:07 +00:00
|
|
|
higher entropy count.
|
|
|
|
This means that it will impact the contents
|
|
|
|
read from both files, but it will not make reads from
|
2013-03-14 10:20:18 +00:00
|
|
|
\fI/dev/random\fP faster.
|
2008-06-18 10:26:36 +00:00
|
|
|
.SS Usage
|
2016-11-10 08:54:27 +00:00
|
|
|
The
|
2008-06-18 10:26:36 +00:00
|
|
|
.IR /dev/random
|
2016-11-10 08:54:27 +00:00
|
|
|
interface is considered a legacy interface, and
|
2016-11-11 09:41:41 +00:00
|
|
|
.IR /dev/urandom
|
2016-11-10 08:54:27 +00:00
|
|
|
is preferred and sufficient in all use cases, with the exception of
|
|
|
|
applications which require randomness during early boot time; for
|
2016-11-10 11:38:58 +00:00
|
|
|
these applications,
|
|
|
|
.BR getrandom (2)
|
|
|
|
must be used instead,
|
|
|
|
because it will block until the entropy pool is initialized.
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2020-04-20 09:51:12 +00:00
|
|
|
If a seed file is saved across reboots as recommended below,
|
|
|
|
the output is
|
2008-06-18 10:26:36 +00:00
|
|
|
cryptographically secure against attackers without local root access as
|
|
|
|
soon as it is reloaded in the boot sequence, and perfectly adequate for
|
|
|
|
network encryption session keys.
|
2020-04-20 09:51:12 +00:00
|
|
|
(All major Linux distributions have saved the seed file across reboots
|
|
|
|
since 2000 at least.)
|
2008-09-18 12:30:45 +00:00
|
|
|
Since reads from
|
2008-06-18 10:26:36 +00:00
|
|
|
.I /dev/random
|
accept.2, connect.2, eventfd.2, flock.2, open.2, posix_fadvise.2, read.2, recv.2, sched_setscheduler.2, select_tut.2, send.2, signalfd.2, splice.2, timerfd_create.2, write.2, flockfile.3, mkfifo.3, mq_notify.3, mq_open.3, pthread_tryjoin_np.3, scanf.3, random.4, ddp.7, epoll.7, fifo.7, ip.7, pipe.7, socket.7, spufs.7: Global fix: s/non-blocking/nonblocking/
The tendency in English, as prescribed in style guides like
Chicago MoS, is towards removing hyphens after prefixes
like "non-" etc.
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2010-01-16 16:43:10 +00:00
|
|
|
may block, users will usually want to open it in nonblocking mode
|
2008-09-18 12:30:45 +00:00
|
|
|
(or perform a read with timeout),
|
|
|
|
and provide some sort of user notification if the desired
|
2008-06-18 10:26:36 +00:00
|
|
|
entropy is not immediately available.
|
2016-11-10 14:10:04 +00:00
|
|
|
.\"
|
2007-06-15 19:35:45 +00:00
|
|
|
.SS Configuration
|
2004-11-03 13:51:07 +00:00
|
|
|
If your system does not have
|
2007-04-12 22:42:49 +00:00
|
|
|
\fI/dev/random\fP and \fI/dev/urandom\fP created already, they
|
2004-11-03 13:51:07 +00:00
|
|
|
can be created with the following commands:
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2017-08-19 08:56:06 +00:00
|
|
|
.in +4n
|
|
|
|
.EX
|
|
|
|
mknod \-m 666 /dev/random c 1 8
|
|
|
|
mknod \-m 666 /dev/urandom c 1 9
|
|
|
|
chown root:root /dev/random /dev/urandom
|
|
|
|
.EE
|
|
|
|
.in
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2007-04-12 22:42:49 +00:00
|
|
|
When a Linux system starts up without much operator interaction,
|
2004-11-03 13:51:07 +00:00
|
|
|
the entropy pool may be in a fairly predictable state.
|
2007-04-12 22:42:49 +00:00
|
|
|
This reduces the actual amount of noise in the entropy pool
|
|
|
|
below the estimate.
|
|
|
|
In order to counteract this effect, it helps to carry
|
|
|
|
entropy pool information across shut-downs and start-ups.
|
2015-12-17 07:47:27 +00:00
|
|
|
To do this, add the lines to an appropriate script
|
2007-04-12 22:42:49 +00:00
|
|
|
which is run during the Linux system start-up sequence:
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2017-08-19 08:56:06 +00:00
|
|
|
.in +4n
|
|
|
|
.EX
|
|
|
|
echo "Initializing random number generator..."
|
2021-01-09 22:21:02 +00:00
|
|
|
random_seed=/var/run/random\-seed
|
|
|
|
# Carry a random seed from start\-up to start\-up
|
2017-08-19 08:56:06 +00:00
|
|
|
# Load and then save the whole entropy pool
|
|
|
|
if [ \-f $random_seed ]; then
|
|
|
|
cat $random_seed >/dev/urandom
|
|
|
|
else
|
|
|
|
touch $random_seed
|
|
|
|
fi
|
|
|
|
chmod 600 $random_seed
|
|
|
|
poolfile=/proc/sys/kernel/random/poolsize
|
|
|
|
[ \-r $poolfile ] && bits=$(cat $poolfile) || bits=4096
|
|
|
|
bytes=$(expr $bits / 8)
|
|
|
|
dd if=/dev/urandom of=$random_seed count=1 bs=$bytes
|
|
|
|
.EE
|
|
|
|
.in
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2007-04-12 22:42:49 +00:00
|
|
|
Also, add the following lines in an appropriate script which is
|
2004-11-03 13:51:07 +00:00
|
|
|
run during the Linux system shutdown:
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2017-08-19 08:56:06 +00:00
|
|
|
.in +4n
|
|
|
|
.EX
|
2021-01-09 22:21:02 +00:00
|
|
|
# Carry a random seed from shut\-down to start\-up
|
2017-08-19 08:56:06 +00:00
|
|
|
# Save the whole entropy pool
|
|
|
|
echo "Saving random seed..."
|
2021-01-09 22:21:02 +00:00
|
|
|
random_seed=/var/run/random\-seed
|
2017-08-19 08:56:06 +00:00
|
|
|
touch $random_seed
|
|
|
|
chmod 600 $random_seed
|
|
|
|
poolfile=/proc/sys/kernel/random/poolsize
|
|
|
|
[ \-r $poolfile ] && bits=$(cat $poolfile) || bits=4096
|
|
|
|
bytes=$(expr $bits / 8)
|
|
|
|
dd if=/dev/urandom of=$random_seed count=1 bs=$bytes
|
|
|
|
.EE
|
|
|
|
.in
|
2017-08-12 20:43:42 +00:00
|
|
|
.PP
|
2015-12-17 07:47:27 +00:00
|
|
|
In the above examples, we assume Linux 2.6.0 or later, where
|
|
|
|
.IR /proc/sys/kernel/random/poolsize
|
|
|
|
returns the size of the entropy pool in bits (see below).
|
2016-11-10 12:31:59 +00:00
|
|
|
.\"
|
|
|
|
.SS /proc interfaces
|
2004-11-03 13:51:07 +00:00
|
|
|
The files in the directory
|
|
|
|
.I /proc/sys/kernel/random
|
2016-11-10 12:31:59 +00:00
|
|
|
(present since 2.3.16) provide additional information about the
|
2005-11-02 13:55:25 +00:00
|
|
|
.I /dev/random
|
2016-11-10 12:31:59 +00:00
|
|
|
device:
|
|
|
|
.TP
|
2004-11-03 13:51:07 +00:00
|
|
|
.I entropy_avail
|
2016-12-13 09:26:45 +00:00
|
|
|
This read-only file gives the available entropy, in bits.
|
|
|
|
This will be a number in the range 0 to 4096.
|
2016-11-10 12:31:59 +00:00
|
|
|
.TP
|
2004-11-03 13:51:07 +00:00
|
|
|
.I poolsize
|
2016-11-10 12:31:59 +00:00
|
|
|
This file
|
2007-04-12 22:42:49 +00:00
|
|
|
gives the size of the entropy pool.
|
2008-01-05 06:04:43 +00:00
|
|
|
The semantics of this file vary across kernel versions:
|
|
|
|
.RS
|
2016-11-10 12:31:59 +00:00
|
|
|
.TP
|
2008-01-05 06:04:43 +00:00
|
|
|
Linux 2.4:
|
|
|
|
This file gives the size of the entropy pool in
|
|
|
|
.IR bytes .
|
|
|
|
Normally, this file will have the value 512, but it is writable,
|
|
|
|
and can be changed to any value for which an algorithm is available.
|
|
|
|
The choices are 32, 64, 128, 256, 512, 1024, or 2048.
|
|
|
|
.TP
|
2017-11-09 08:30:08 +00:00
|
|
|
Linux 2.6 and later:
|
2008-01-05 06:04:43 +00:00
|
|
|
This file is read-only, and gives the size of the entropy pool in
|
|
|
|
.IR bits .
|
|
|
|
It contains the value 4096.
|
|
|
|
.RE
|
2016-11-10 12:31:59 +00:00
|
|
|
.TP
|
2004-11-03 13:51:07 +00:00
|
|
|
.I read_wakeup_threshold
|
2016-11-10 12:31:59 +00:00
|
|
|
This file
|
2004-11-03 13:51:07 +00:00
|
|
|
contains the number of bits of entropy required for waking up processes
|
|
|
|
that sleep waiting for entropy from
|
2005-11-02 11:34:24 +00:00
|
|
|
.IR /dev/random .
|
2004-11-03 13:51:07 +00:00
|
|
|
The default is 64.
|
2016-11-10 12:31:59 +00:00
|
|
|
.TP
|
2004-11-03 13:51:07 +00:00
|
|
|
.I write_wakeup_threshold
|
2016-11-10 12:31:59 +00:00
|
|
|
This file
|
2004-11-03 13:51:07 +00:00
|
|
|
contains the number of bits of entropy below which we wake up
|
|
|
|
processes that do a
|
2007-05-11 23:18:56 +00:00
|
|
|
.BR select (2)
|
2004-11-03 13:51:07 +00:00
|
|
|
or
|
2007-05-11 23:18:56 +00:00
|
|
|
.BR poll (2)
|
2004-11-03 13:51:07 +00:00
|
|
|
for write access to
|
2005-11-02 11:34:24 +00:00
|
|
|
.IR /dev/random .
|
2004-11-03 13:51:07 +00:00
|
|
|
These values can be changed by writing to the files.
|
2016-11-10 12:31:59 +00:00
|
|
|
.TP
|
|
|
|
.IR uuid " and " boot_id
|
|
|
|
These read-only files
|
2004-11-03 13:51:07 +00:00
|
|
|
contain random strings like 6fd5a44b-35f4-4ad4-a9b9-6b9be13e1fe9.
|
|
|
|
The former is generated afresh for each read, the latter was
|
|
|
|
generated once.
|
2016-11-10 12:31:59 +00:00
|
|
|
.\"
|
2013-03-14 10:20:18 +00:00
|
|
|
.SS ioctl(2) interface
|
|
|
|
The following
|
|
|
|
.BR ioctl (2)
|
|
|
|
requests are defined on file descriptors connected to either \fI/dev/random\fP
|
2013-03-14 10:29:07 +00:00
|
|
|
or \fI/dev/urandom\fP.
|
|
|
|
All requests performed will interact with the input
|
2013-03-14 10:20:18 +00:00
|
|
|
entropy pool impacting both \fI/dev/random\fP and \fI/dev/urandom\fP.
|
|
|
|
The
|
|
|
|
.B CAP_SYS_ADMIN
|
|
|
|
capability is required for all requests except
|
2013-03-14 10:29:07 +00:00
|
|
|
.BR RNDGETENTCNT .
|
2013-03-14 10:20:18 +00:00
|
|
|
.TP
|
|
|
|
.BR RNDGETENTCNT
|
|
|
|
Retrieve the entropy count of the input pool, the contents will be the same
|
|
|
|
as the
|
|
|
|
.I entropy_avail
|
|
|
|
file under proc.
|
|
|
|
The result will be stored in the int pointed to by the argument.
|
|
|
|
.TP
|
|
|
|
.BR RNDADDTOENTCNT
|
2013-03-14 10:29:07 +00:00
|
|
|
Increment or decrement the entropy count of the input pool
|
|
|
|
by the value pointed to by the argument.
|
2013-03-14 10:20:18 +00:00
|
|
|
.TP
|
|
|
|
.BR RNDGETPOOL
|
|
|
|
Removed in Linux 2.6.9.
|
|
|
|
.TP
|
|
|
|
.BR RNDADDENTROPY
|
2013-03-14 10:29:07 +00:00
|
|
|
Add some additional entropy to the input pool,
|
|
|
|
incrementing the entropy count.
|
|
|
|
This differs from writing to \fI/dev/random\fP or \fI/dev/urandom\fP,
|
|
|
|
which only adds some
|
|
|
|
data but does not increment the entropy count.
|
|
|
|
The following structure is used:
|
2013-03-14 10:20:18 +00:00
|
|
|
.IP
|
2017-08-19 08:33:24 +00:00
|
|
|
.in +4n
|
|
|
|
.EX
|
|
|
|
struct rand_pool_info {
|
|
|
|
int entropy_count;
|
|
|
|
int buf_size;
|
|
|
|
__u32 buf[0];
|
|
|
|
};
|
|
|
|
.EE
|
|
|
|
.in
|
2013-03-14 10:20:18 +00:00
|
|
|
.IP
|
|
|
|
Here
|
|
|
|
.I entropy_count
|
2013-03-17 07:09:34 +00:00
|
|
|
is the value added to (or subtracted from) the entropy count, and
|
2013-03-14 10:20:18 +00:00
|
|
|
.I buf
|
|
|
|
is the buffer of size
|
|
|
|
.I buf_size
|
|
|
|
which gets added to the entropy pool.
|
|
|
|
.TP
|
|
|
|
.BR RNDZAPENTCNT ", " RNDCLEARPOOL
|
|
|
|
Zero the entropy count of all pools and add some system data (such as
|
|
|
|
wall clock) to the pools.
|
2017-09-06 16:09:19 +00:00
|
|
|
.SH FILES
|
2018-01-06 21:54:02 +00:00
|
|
|
.I /dev/random
|
2017-09-06 16:09:19 +00:00
|
|
|
.br
|
2018-01-06 21:54:02 +00:00
|
|
|
.I /dev/urandom
|
2016-11-11 21:27:05 +00:00
|
|
|
.SH NOTES
|
|
|
|
For an overview and comparison of the various interfaces that
|
|
|
|
can be used to obtain randomness, see
|
|
|
|
.BR random (7).
|
2016-11-10 11:38:58 +00:00
|
|
|
.SH BUGS
|
2016-11-10 12:28:27 +00:00
|
|
|
During early boot time, reads from
|
2016-11-10 11:38:58 +00:00
|
|
|
.I /dev/urandom
|
|
|
|
may return data prior to the entropy pool being initialized.
|
2007-05-16 03:44:47 +00:00
|
|
|
.\" .SH AUTHOR
|
|
|
|
.\" The kernel's random number generator was written by
|
|
|
|
.\" Theodore Ts'o (tytso@athena.mit.edu).
|
getent.1, intro.1, time.1, _exit.2, _syscall.2, accept.2, access.2, acct.2, adjtimex.2, alarm.2, alloc_hugepages.2, arch_prctl.2, bdflush.2, bind.2, brk.2, cacheflush.2, capget.2, chdir.2, chmod.2, chown.2, chroot.2, clock_getres.2, clock_nanosleep.2, clone.2, close.2, connect.2, create_module.2, delete_module.2, dup.2, epoll_create.2, epoll_ctl.2, epoll_wait.2, eventfd.2, execve.2, exit_group.2, faccessat.2, fchmodat.2, fchownat.2, fcntl.2, flock.2, fork.2, fstatat.2, fsync.2, futex.2, futimesat.2, get_kernel_syms.2, get_robust_list.2, get_thread_area.2, getcpu.2, getdents.2, getdomainname.2, getgid.2, getgroups.2, gethostname.2, getitimer.2, getpagesize.2, getpeername.2, getpid.2, getpriority.2, getresuid.2, getrlimit.2, getrusage.2, getsid.2, getsockname.2, getsockopt.2, gettid.2, gettimeofday.2, getuid.2, getunwind.2, getxattr.2, idle.2, init_module.2, inotify_add_watch.2, inotify_init.2, inotify_rm_watch.2, intro.2, io_cancel.2, io_destroy.2, io_getevents.2, io_setup.2, io_submit.2, ioctl.2, ioctl_list.2, ioperm.2, iopl.2, ioprio_set.2, ipc.2, kcmp.2, kill.2, killpg.2, link.2, linkat.2, listen.2, listxattr.2, llseek.2, lookup_dcookie.2, lseek.2, madvise.2, migrate_pages.2, mincore.2, mkdir.2, mkdirat.2, mknod.2, mknodat.2, mlock.2, mmap.2, mmap2.2, modify_ldt.2, mount.2, move_pages.2, mprotect.2, mq_getsetattr.2, mremap.2, msgctl.2, msgget.2, msgop.2, msync.2, nanosleep.2, nfsservctl.2, nice.2, open.2, openat.2, outb.2, pause.2, pciconfig_read.2, perf_event_open.2, perfmonctl.2, personality.2, pipe.2, pivot_root.2, poll.2, posix_fadvise.2, prctl.2, pread.2, process_vm_readv.2, ptrace.2, query_module.2, quotactl.2, read.2, readahead.2, readdir.2, readlink.2, readlinkat.2, readv.2, reboot.2, recv.2, remap_file_pages.2, removexattr.2, rename.2, renameat.2, rmdir.2, rt_sigqueueinfo.2, sched_get_priority_max.2, sched_rr_get_interval.2, sched_setaffinity.2, sched_setparam.2, sched_setscheduler.2, sched_yield.2, select.2, semctl.2, semget.2, semop.2, send.2, sendfile.2, set_thread_area.2, set_tid_address.2, seteuid.2, setfsgid.2, setfsuid.2, setgid.2, setpgid.2, setresuid.2, setreuid.2, setsid.2, setuid.2, setup.2, setxattr.2, shmctl.2, shmget.2, shmop.2, shutdown.2, sigaction.2, sigaltstack.2, signal.2, signalfd.2, sigpending.2, sigprocmask.2, sigreturn.2, sigsuspend.2, sigwaitinfo.2, socket.2, socketcall.2, socketpair.2, splice.2, stat.2, statfs.2, stime.2, swapon.2, symlink.2, symlinkat.2, sync.2, sync_file_range.2, sysctl.2, sysfs.2, sysinfo.2, syslog.2, tee.2, time.2, timerfd_create.2, times.2, tkill.2, truncate.2, umask.2, umount.2, uname.2, unimplemented.2, unlink.2, unlinkat.2, uselib.2, ustat.2, utime.2, utimensat.2, vfork.2, vhangup.2, vm86.2, vmsplice.2, wait.2, wait4.2, write.2, CPU_SET.3, INFINITY.3, MB_CUR_MAX.3, MB_LEN_MAX.3, __setfpucw.3, a64l.3, abort.3, abs.3, acos.3, acosh.3, addseverity.3, adjtime.3, aio_cancel.3, aio_error.3, aio_fsync.3, aio_read.3, aio_return.3, aio_suspend.3, aio_write.3, alloca.3, argz_add.3, asin.3, asinh.3, asprintf.3, assert.3, assert_perror.3, atan.3, atan2.3, atanh.3, atexit.3, atof.3, atoi.3, backtrace.3, basename.3, bcmp.3, bcopy.3, bindresvport.3, bsd_signal.3, bsearch.3, bstring.3, btowc.3, btree.3, byteorder.3, bzero.3, cabs.3, cacos.3, cacosh.3, canonicalize_file_name.3, carg.3, casin.3, casinh.3, catan.3, catanh.3, catgets.3, catopen.3, cbrt.3, ccos.3, ccosh.3, ceil.3, cerf.3, cexp.3, cexp2.3, cfree.3, cimag.3, clearenv.3, clock.3, clock_getcpuclockid.3, clog.3, clog10.3, clog2.3, closedir.3, cmsg.3, confstr.3, conj.3, copysign.3, cos.3, cosh.3, cpow.3, cproj.3, creal.3, crypt.3, csin.3, csinh.3, csqrt.3, ctan.3, ctanh.3, ctermid.3, ctime.3, daemon.3, dbopen.3, des_crypt.3, difftime.3, dirfd.3, div.3, dl_iterate_phdr.3, dlopen.3, dprintf.3, drand48.3, drand48_r.3, dysize.3, ecvt.3, ecvt_r.3, encrypt.3, end.3, endian.3, envz_add.3, erf.3, erfc.3, err.3, errno.3, error.3, ether_aton.3, euidaccess.3, exec.3, exit.3, exp.3, exp10.3, exp2.3, expm1.3, fabs.3, fclose.3, fcloseall.3, fdim.3, fenv.3, ferror.3, fexecve.3, fflush.3, ffs.3, fgetgrent.3, fgetpwent.3, fgetwc.3, fgetws.3, finite.3, flockfile.3, floor.3, fma.3, fmax.3, fmemopen.3, fmin.3, fmod.3, fmtmsg.3, fnmatch.3, fopen.3, fpathconf.3, fpclassify.3, fpurge.3, fputwc.3, fputws.3, fread.3, frexp.3, fseek.3, fseeko.3, ftime.3, ftok.3, fts.3, ftw.3, futimes.3, fwide.3, gamma.3, gcvt.3, getaddrinfo.3, getaddrinfo_a.3, getauxval.3, getcontext.3, getcwd.3, getdate.3, getdirentries.3, getdtablesize.3, getenv.3, getfsent.3, getgrent.3, getgrent_r.3, getgrnam.3, getgrouplist.3, gethostbyname.3, gethostid.3, getipnodebyname.3, getline.3, getloadavg.3, getlogin.3, getmntent.3, getnameinfo.3, getnetent.3, getnetent_r.3, getopt.3, getpass.3, getprotoent.3, getprotoent_r.3, getpt.3, getpw.3, getpwent.3, getpwent_r.3, getpwnam.3, getrpcent.3, getrpcent_r.3, getrpcport.3, gets.3, getservent.3, getservent_r.3, getspnam.3, getttyent.3, getumask.3, getusershell.3, getutent.3, getw.3, getwchar.3, glob.3, grantpt.3, gsignal.3, hash.3, hsearch.3, hypot.3, iconv.3, iconv_close.3, iconv_open.3, ilogb.3, index.3, inet.3, inet_ntop.3, inet_pton.3, infnan.3, initgroups.3, insque.3, intro.3, isalpha.3, isatty.3, isgreater.3, iswalnum.3, iswalpha.3, iswblank.3, iswcntrl.3, iswctype.3, iswdigit.3, iswgraph.3, iswlower.3, iswprint.3, iswpunct.3, iswspace.3, iswupper.3, iswxdigit.3, j0.3, key_setsecret.3, ldexp.3, lgamma.3, lio_listio.3, localeconv.3, lockf.3, log.3, log10.3, log1p.3, log2.3, logb.3, login.3, longjmp.3, lrint.3, lround.3, lsearch.3, lseek64.3, makecontext.3, makedev.3, malloc.3, malloc_hook.3, mblen.3, mbrlen.3, mbrtowc.3, mbsinit.3, mbsnrtowcs.3, mbsrtowcs.3, mbstowcs.3, mbtowc.3, memccpy.3, memchr.3, memcmp.3, memcpy.3, memfrob.3, memmem.3, memmove.3, mempcpy.3, memset.3, mkdtemp.3, mkfifo.3, mkfifoat.3, mkstemp.3, mktemp.3, modf.3, mpool.3, mq_close.3, mq_getattr.3, mq_notify.3, mq_open.3, mq_receive.3, mq_send.3, mq_unlink.3, mtrace.3, nan.3, netlink.3, nextafter.3, nl_langinfo.3, offsetof.3, on_exit.3, opendir.3, openpty.3, perror.3, popen.3, posix_fallocate.3, posix_memalign.3, posix_openpt.3, pow.3, pow10.3, printf.3, profil.3, program_invocation_name.3, psignal.3, pthread_kill_other_threads_np.3, ptsname.3, putenv.3, putgrent.3, putpwent.3, puts.3, putwchar.3, qecvt.3, qsort.3, queue.3, raise.3, rand.3, random.3, random_r.3, rcmd.3, re_comp.3, readdir.3, realpath.3, recno.3, regex.3, remainder.3, remove.3, remquo.3, resolver.3, rewinddir.3, rexec.3, rint.3, round.3, rpc.3, rpmatch.3, rtime.3, rtnetlink.3, scalb.3, scalbln.3, scandir.3, scandirat.3, scanf.3, seekdir.3, sem_close.3, sem_destroy.3, sem_getvalue.3, sem_init.3, sem_open.3, sem_post.3, sem_unlink.3, sem_wait.3, setaliasent.3, setbuf.3, setenv.3, setjmp.3, setlocale.3, setlogmask.3, setnetgrent.3, shm_open.3, siginterrupt.3, signbit.3, significand.3, sigpause.3, sigqueue.3, sigset.3, sigsetops.3, sigvec.3, sin.3, sincos.3, sinh.3, sleep.3, sockatmark.3, sqrt.3, statvfs.3, stdarg.3, stdin.3, stdio.3, stdio_ext.3, stpcpy.3, stpncpy.3, strcasecmp.3, strcat.3, strchr.3, strcmp.3, strcoll.3, strcpy.3, strdup.3, strerror.3, strfmon.3, strfry.3, strftime.3, string.3, strlen.3, strnlen.3, strpbrk.3, strptime.3, strsep.3, strsignal.3, strspn.3, strstr.3, strtod.3, strtoimax.3, strtok.3, strtol.3, strtoul.3, strverscmp.3, strxfrm.3, swab.3, sysconf.3, syslog.3, system.3, sysv_signal.3, tan.3, tanh.3, tcgetpgrp.3, tcgetsid.3, telldir.3, tempnam.3, termios.3, tgamma.3, timegm.3, timeradd.3, tmpfile.3, tmpnam.3, toascii.3, toupper.3, towctrans.3, towlower.3, towupper.3, trunc.3, tsearch.3, ttyname.3, ttyslot.3, tzset.3, ualarm.3, ulimit.3, ungetwc.3, unlocked_stdio.3, unlockpt.3, updwtmp.3, usleep.3, wcpcpy.3, wcpncpy.3, wcrtomb.3, wcscasecmp.3, wcscat.3, wcschr.3, wcscmp.3, wcscpy.3, wcscspn.3, wcsdup.3, wcslen.3, wcsncasecmp.3, wcsncat.3, wcsncmp.3, wcsncpy.3, wcsnlen.3, wcsnrtombs.3, wcspbrk.3, wcsrchr.3, wcsrtombs.3, wcsspn.3, wcsstr.3, wcstoimax.3, wcstok.3, wcstombs.3, wcswidth.3, wctob.3, wctomb.3, wctrans.3, wctype.3, wcwidth.3, wmemchr.3, wmemcmp.3, wmemcpy.3, wmemmove.3, wmemset.3, wordexp.3, wprintf.3, xcrypt.3, xdr.3, y0.3, cciss.4, console.4, console_codes.4, console_ioctl.4, dsp56k.4, fd.4, full.4, hd.4, hpsa.4, initrd.4, intro.4, lp.4, mem.4, mouse.4, null.4, pts.4, ram.4, random.4, rtc.4, sk98lin.4, st.4, tty.4, ttyS.4, tty_ioctl.4, vcs.4, wavelan.4, acct.5, charmap.5, dir_colors.5, filesystems.5, ftpusers.5, group.5, host.conf.5, hosts.5, hosts.equiv.5, intro.5, issue.5, locale.5, motd.5, networks.5, nologin.5, nscd.conf.5, passwd.5, proc.5, protocols.5, resolv.conf.5, rpc.5, securetty.5, services.5, shells.5, termcap.5, ttytype.5, utmp.5, armscii-8.7, arp.7, ascii.7, bootparam.7, capabilities.7, charsets.7, complex.7, cp1251.7, credentials.7, ddp.7, environ.7, epoll.7, fifo.7, futex.7, glob.7, hier.7, icmp.7, inotify.7, intro.7, ip.7, ipv6.7, iso_8859-1.7, iso_8859-10.7, iso_8859-11.7, iso_8859-13.7, iso_8859-14.7, iso_8859-15.7, iso_8859-16.7, iso_8859-2.7, iso_8859-3.7, iso_8859-4.7, iso_8859-5.7, iso_8859-6.7, iso_8859-7.7, iso_8859-8.7, iso_8859-9.7, koi8-r.7, koi8-u.7, locale.7, mailaddr.7, man.7, mq_overview.7, netdevice.7, netlink.7, numa.7, packet.7, path_resolution.7, pipe.7, posixoptions.7, pthreads.7, pty.7, raw.7, regex.7, rtld-audit.7, rtnetlink.7, sem_overview.7, shm_overview.7, sigevent.7, signal.7, socket.7, standards.7, suffixes.7, svipc.7, tcp.7, termio.7, time.7, udp.7, udplite.7, unicode.7, unix.7, uri.7, utf-8.7, x25.7, nscd.8, sync.8, tzselect.8, zdump.8, zic.8: Global fix: remove unneeded double quotes in .SH headings
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
2013-02-24 18:01:36 +00:00
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.SH SEE ALSO
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2016-08-07 18:37:26 +00:00
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.BR mknod (1),
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2016-11-11 21:27:05 +00:00
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.BR getrandom (2),
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.BR random (7)
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2017-08-12 20:43:42 +00:00
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.PP
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2005-07-20 07:50:45 +00:00
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RFC\ 1750, "Randomness Recommendations for Security"
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