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* [glibc] hurd: add getrandom and getentropy implementations
@ 2019-12-13 2:24 Samuel Thibault
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From: Samuel Thibault @ 2019-12-13 2:24 UTC (permalink / raw)
To: glibc-cvs
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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