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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:43:11 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:43:11 +0000 |
commit | fc22b3d6507c6745911b9dfcc68f1e665ae13dbc (patch) | |
tree | ce1e3bce06471410239a6f41282e328770aa404a /upstream/mageia-cauldron/man3/getentropy.3 | |
parent | Initial commit. (diff) | |
download | manpages-l10n-fc22b3d6507c6745911b9dfcc68f1e665ae13dbc.tar.xz manpages-l10n-fc22b3d6507c6745911b9dfcc68f1e665ae13dbc.zip |
Adding upstream version 4.22.0.upstream/4.22.0
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'upstream/mageia-cauldron/man3/getentropy.3')
-rw-r--r-- | upstream/mageia-cauldron/man3/getentropy.3 | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/upstream/mageia-cauldron/man3/getentropy.3 b/upstream/mageia-cauldron/man3/getentropy.3 new file mode 100644 index 00000000..7d6c5aba --- /dev/null +++ b/upstream/mageia-cauldron/man3/getentropy.3 @@ -0,0 +1,103 @@ +.\" Copyright (C) 2017, Michael Kerrisk <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH getentropy 3 2023-10-31 "Linux man-pages 6.06" +.SH NAME +getentropy \- fill a buffer with random bytes +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <unistd.h> +.P +.BI "int getentropy(void " buffer [. length "], size_t " length ); +.fi +.P +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.P +.BR getentropy (): +.nf + _DEFAULT_SOURCE +.fi +.SH DESCRIPTION +The +.BR getentropy () +function writes +.I length +bytes of high-quality random data to the buffer starting +at the location pointed to by +.IR buffer . +The maximum permitted value for the +.I length +argument is 256. +.P +A successful call to +.BR getentropy () +always provides the requested number of bytes of entropy. +.SH RETURN VALUE +On success, this function returns zero. +On error, \-1 is returned, and +.I errno +is set to indicate the error. +.SH ERRORS +.TP +.B EFAULT +Part or all of the buffer specified by +.I buffer +and +.I length +is not in valid addressable memory. +.TP +.B EIO +.I length +is greater than 256. +.TP +.B EIO +An unspecified error occurred while trying to overwrite +.I buffer +with random data. +.TP +.B ENOSYS +This kernel version does not implement the +.BR getrandom (2) +system call required to implement this function. +.SH STANDARDS +None. +.SH HISTORY +glibc 2.25. +OpenBSD. +.SH NOTES +The +.BR getentropy () +function is implemented using +.BR getrandom (2). +.P +Whereas the glibc wrapper makes +.BR getrandom (2) +a cancelation point, +.BR getentropy () +is not a cancelation point. +.P +.BR getentropy () +is also declared in +.BR <sys/random.h> . +(No feature test macro need be defined to obtain the declaration from +that header file.) +.P +A call to +.BR getentropy () +may block if the system has just booted and the kernel has +not yet collected enough randomness to initialize the entropy pool. +In this case, +.BR getentropy () +will keep blocking even if a signal is handled, +and will return only once the entropy pool has been initialized. +.SH SEE ALSO +.BR getrandom (2), +.BR urandom (4), +.BR random (7) |