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Use getentropy() for seeding PRNG 

The getentropy function, found on Linux, OpenBSD, and recently also
FreeBSD, can be used to get random bytes to initialize the PRNG.  It
is similar to the traditional way of reading from /dev/urandom, but
being a system call rather than a special file, it doesn't suffer from
problems like running out of file descriptors, or failure when running
in a container where /dev/urandom may not be available.

Regtested on x86_64-pc-linux-gnu, Ok for trunk?

2018-08-13  Janne Blomqvist  <jb@gcc.gnu.org>

	* configure.ac: Check for getentropy.
	* intrinsics/random.c (getosrandom): Use getentropy if available.
	* config.h.in: Regenerated.
	* configure: Regenerated.

From-SVN: r263522
This commit is contained in:
Janne Blomqvist 2018-08-13 23:21:50 +03:00
parent 72217988ca
commit d66d6d15f1
5 changed files with 21 additions and 8 deletions
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7
libgfortran/ChangeLog
View File

@ -1,3 +1,10 @@
2018-08-13 Janne Blomqvist <jb@gcc.gnu.org>
* configure.ac: Check for getentropy.
* intrinsics/random.c (getosrandom): Use getentropy if available.
* config.h.in: Regenerated.
* configure: Regenerated.
2018-07-31 Andre Vieira <andre.simoesdiasvieira@arm.com>
Revert 'AsyncI/O patch committed'

3
libgfortran/config.h.in
View File

@ -453,6 +453,9 @@
/* Define to 1 if you have the `getegid' function. */
#undef HAVE_GETEGID
/* Define to 1 if you have the `getentropy' function. */
#undef HAVE_GETENTROPY
/* Define to 1 if you have the `geteuid' function. */
#undef HAVE_GETEUID

7
libgfortran/configure vendored
View File

@ -2570,6 +2570,7 @@ as_fn_append ac_func_list " snprintf"
as_fn_append ac_func_list " ftruncate"
as_fn_append ac_func_list " chsize"
as_fn_append ac_func_list " chdir"
as_fn_append ac_func_list " getentropy"
as_fn_append ac_func_list " getlogin"
as_fn_append ac_func_list " gethostname"
as_fn_append ac_func_list " kill"
@ -12512,7 +12513,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
#line 12515 "configure"
#line 12516 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@ -12618,7 +12619,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
#line 12621 "configure"
#line 12622 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@ -16775,6 +16776,8 @@ done

3
libgfortran/configure.ac
View File

@ -312,7 +312,8 @@ if test "${hardwire_newlib:-0}" -eq 1; then
fi
else
AC_CHECK_FUNCS_ONCE(getrusage times mkstemp strtof strtold snprintf \
ftruncate chsize chdir getlogin gethostname kill link symlink sleep ttyname \
ftruncate chsize chdir getentropy getlogin gethostname kill link symlink \
sleep ttyname \
alarm access fork setmode fcntl \
gettimeofday stat fstat lstat getpwuid vsnprintf dup \
getcwd localtime_r gmtime_r getpwuid_r ttyname_r clock_gettime \

9
libgfortran/intrinsics/random.c
View File

@ -310,11 +310,10 @@ getosrandom (void *buf, size_t buflen)
rand_s (&b[i]);
return buflen;
#else
/*
TODO: When glibc adds a wrapper for the getrandom() system call
on Linux, one could use that.
TODO: One could use getentropy() on OpenBSD. */
#ifdef HAVE_GETENTROPY
if (getentropy (buf, buflen) == 0)
return 0;
#endif
int flags = O_RDONLY;
#ifdef O_CLOEXEC
flags |= O_CLOEXEC;