summaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorriastradh <riastradh@NetBSD.org>2022-05-31 13:42:58 +0000
committerriastradh <riastradh@NetBSD.org>2022-05-31 13:42:58 +0000
commit5a243ca784b423d6c39f02521029e7151e76908a (patch)
treec52498d34dae03252fb5c2ca710755d15ccadd9a /include
parenta6efbbf4d8ff7f6f492caa04dd41cac9bc4a5f56 (diff)
libc: Reintroduce getentropy.
This was introduced two years ago when the getrandom/getentropy API question was still open, and removed because the discussion was ongoing. Now getentropy is more widely adopted and soon to be in POSIX. So reintroduce the symbol into libc since we'll be keeping it anyway. Discussion of details of the semantics, as interpreted by NetBSD, is ongoing, but the symbol needs to get in before the netbsd-10 branch. The draft POSIX text is (https://www.opengroup.org/austin/docs/austin_1110.pdf): SYNOPSIS #include <unistd.h> int getentropy(void *buffer, size_t length); DESCRIPTION The getentropy() function shall write length bytes of data starting at the location pointed to by buffer. The output shall be unpredictable high quality random data, generated by a cryptographically secure pseudo-random number generator. The maximum permitted value for the length argument is given by the {GETENTROPY_MAX} symbolic constant defined in <limits.h>. RETURN VALUES Upon successful completion, getentropy() shall return 0; otherwise, -1 shall be retunred and errno set to indicate the error. ERRORS The getentropy() function shall fail if: [EINVAL] The value of length is greater than {GETENTROPY_MAX}. The getentropy() function may fail if: [ENOSYS] The system does not provide the necessary source of entropy. RATIONALE The getentropy() function is not a cancellation point. Minor changes from the previous introduction of getentropy into libc: - Return EINVAL, not EIO, on buflen > 256. - Define GETENTROPY_MAX in limits.h. The declaration of getentropy in unistd.h and definition of GETENTROPY_MAX in limits.h are currently conditional on _NETBSD_SOURCE. When the next revision of POSIX is finalized, we can expose them also under _POSIX_C_SOURCE > 20yymmL as usual -- and this can be done as a pullup without breaking existing compiled programs.
Diffstat (limited to 'include')
-rw-r--r--include/limits.h6
-rw-r--r--include/unistd.h3
2 files changed, 7 insertions, 2 deletions
diff --git a/include/limits.h b/include/limits.h
index 12c25c73b24..98591592ad3 100644
--- a/include/limits.h
+++ b/include/limits.h
@@ -1,4 +1,4 @@
-/* $NetBSD: limits.h,v 1.42 2019/09/15 23:52:59 christos Exp $ */
+/* $NetBSD: limits.h,v 1.43 2022/05/31 13:42:59 riastradh Exp $ */
/*
* Copyright (c) 1988, 1993
@@ -144,6 +144,10 @@
#define MB_LEN_MAX 32 /* Allow ISO/IEC 2022 */
+#ifdef _NETBSD_SOURCE
+#define GETENTROPY_MAX 256
+#endif
+
#include <machine/limits.h>
#ifdef __CHAR_UNSIGNED__
diff --git a/include/unistd.h b/include/unistd.h
index ea941acb76a..a4be358a994 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -1,4 +1,4 @@
-/* $NetBSD: unistd.h,v 1.162 2021/10/15 22:32:28 andvar Exp $ */
+/* $NetBSD: unistd.h,v 1.163 2022/05/31 13:42:59 riastradh Exp $ */
/*-
* Copyright (c) 1998, 1999, 2008 The NetBSD Foundation, Inc.
@@ -338,6 +338,7 @@ int fchroot(int);
int fdiscard(int, off_t, off_t);
int fsync_range(int, int, off_t, off_t);
int getdomainname(char *, size_t);
+int getentropy(void *, size_t);
int getgrouplist(const char *, gid_t, gid_t *, int *);
int getgroupmembership(const char *, gid_t, gid_t *, int, int *);
mode_t getmode(const void *, mode_t);