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From: Samuel Thibault <sthibaul@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc] hurd: add getrandom and getentropy implementations Date: Fri, 13 Dec 2019 02:24:00 -0000 [thread overview] Message-ID: <20191213022455.121328.qmail@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=fe75ee0ca65536352fcdaebfbf39aac9bee271f0 commit fe75ee0ca65536352fcdaebfbf39aac9bee271f0 Author: Andrew Eggenberger <andrew.eggenberger@gmail.com> Date: Tue Oct 29 23:19:32 2019 -0500 hurd: add getrandom and getentropy implementations * sysdeps/mach/hurd/getentropy.c: New file. * sysdeps/mach/hurd/getrandom.c: Likewise. Diff: --- sysdeps/mach/hurd/getentropy.c | 64 ++++++++++++++++++++++++++++++++++++++++++ sysdeps/mach/hurd/getrandom.c | 43 ++++++++++++++++++++++++++++ 2 files changed, 107 insertions(+) diff --git a/sysdeps/mach/hurd/getentropy.c b/sysdeps/mach/hurd/getentropy.c new file mode 100644 index 0000000..d55eec8 --- /dev/null +++ b/sysdeps/mach/hurd/getentropy.c @@ -0,0 +1,64 @@ +/* Implementation of getentropy based on getrandom. + Copyright (C) 2016-2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <sys/random.h> +#include <assert.h> +#include <errno.h> +#include <unistd.h> + +/* Write LENGTH bytes of randomness starting at BUFFER. Return 0 on + success and -1 on failure. */ +int +getentropy (void *buffer, size_t length) +{ + /* The interface is documented to return EIO for buffer lengths + longer than 256 bytes. */ + if (length > 256) + { + __set_errno (EIO); + return -1; + } + + /* Try to fill the buffer completely. Even with the 256 byte limit + above, we might still receive an EINTR error (when blocking + during boot). */ + void *end = buffer + length; + while (buffer < end) + { + /* NB: No cancellation point. */ + ssize_t bytes = getrandom (buffer, end - buffer, 0); + if (bytes < 0) + { + if (errno == EINTR) + /* Try again if interrupted by a signal. */ + continue; + else + return -1; + } + if (bytes == 0) + { + /* No more bytes available. This should not happen under + normal circumstances. */ + __set_errno (EIO); + return -1; + } + /* Try again in case of a short read. */ + buffer += bytes; + } + return 0; +} diff --git a/sysdeps/mach/hurd/getrandom.c b/sysdeps/mach/hurd/getrandom.c new file mode 100644 index 0000000..0147aee --- /dev/null +++ b/sysdeps/mach/hurd/getrandom.c @@ -0,0 +1,43 @@ +/* Hurdish implementation of getrandom + Copyright (C) 2016-2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <sys/random.h> +#include <fcntl.h> +#include <unistd.h> +#include <not-cancel.h> + +/* Write up to LENGTH bytes of randomness starting at BUFFER. + Return the number of bytes written, or -1 on error. */ +ssize_t +getrandom (void *buffer, size_t length, unsigned int flags) +{ + const char *random_source = "/dev/urandom"; + size_t amount_read; + int fd; + + if (flags & GRND_RANDOM) + random_source = "/dev/random"; + + fd = __open_nocancel(random_source, O_RDONLY | O_CLOEXEC); + if (fd == -1) + return -1; + + amount_read = __read_nocancel(fd, buffer, length); + __close_nocancel_nostatus(fd); + return amount_read; +}
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