Add elf_aux_info(3)

Designed to let userland peek at AT_HWCAP and AT_HWCAP2 using an already
existing interface coming from FreeBSD. Headers bits were snatched from
there.  Input & ok kettenis@

libc bump and sets sync will follow soon

3 files changed, 59 insertions, 1 deletions

diff --git a/regress/lib/libc/Makefile b/regress/lib/libc/Makefile
index 8b5e4d45034..3cd970e49d5 100644
--- a/regress/lib/libc/Makefile
+++ b/regress/lib/libc/Makefile
@@ -1,10 +1,11 @@
-#	$OpenBSD: Makefile,v 1.58 2021/08/31 09:58:17 jasper Exp $
+#	$OpenBSD: Makefile,v 1.59 2024/07/14 09:48:48 jca Exp $
 
 SUBDIR+= _setjmp
 SUBDIR+= alloca arc4random-fork atexit
 SUBDIR+= basename
 SUBDIR+= cephes cxa-atexit
 SUBDIR+= db dirname
+SUBDIR+= elf_aux_info
 SUBDIR+= env explicit_bzero
 SUBDIR+= ffs fmemopen fnmatch fpclassify fread
 SUBDIR+= gcvt getaddrinfo getcap getopt getopt_long glob
diff --git a/regress/lib/libc/elf_aux_info/Makefile b/regress/lib/libc/elf_aux_info/Makefile
new file mode 100644
index 00000000000..2885fb18512
--- /dev/null
+++ b/regress/lib/libc/elf_aux_info/Makefile
@@ -0,0 +1,3 @@
+PROG=elf_aux_info
+
+.include <bsd.regress.mk>
diff --git a/regress/lib/libc/elf_aux_info/elf_aux_info.c b/regress/lib/libc/elf_aux_info/elf_aux_info.c
new file mode 100644
index 00000000000..481085d6d97
--- /dev/null
+++ b/regress/lib/libc/elf_aux_info/elf_aux_info.c
@@ -0,0 +1,54 @@
+#include <sys/auxv.h>
+
+#include <errno.h>
+#include <stdio.h>
+
+int
+main(void)
+{
+	int ret = 0;
+	int a;
+	unsigned long b;
+
+
+	/* Should always succeed */
+	if (elf_aux_info(AT_PAGESZ, &a, sizeof(a)))
+		ret |= 1;
+	else
+		fprintf(stderr, "AT_PAGESZ %d\n", a);
+
+	/* Wrong size */
+	if (elf_aux_info(AT_PAGESZ, &b, sizeof(b)) != EINVAL)
+		ret |= 2;
+
+	/* Invalid request */
+	if (elf_aux_info(-1, &a, sizeof(a)) != EINVAL)
+		ret |= 4;
+
+	/* Should either succeed or fail with ENOENT if not supported */
+	switch (elf_aux_info(AT_HWCAP, &b, sizeof(b))) {
+	case 0:
+		fprintf(stderr, "AT_HWCAP %lx\n", b);
+		break;
+	case ENOENT:
+		break;
+	default:
+		ret |= 8;
+	}
+
+	/* Should either succeed or fail with ENOENT if not supported */
+	switch (elf_aux_info(AT_HWCAP2, &b, sizeof(b))) {
+	case 0:
+		fprintf(stderr, "AT_HWCAP2 %lx\n", b);
+		break;
+	case ENOENT:
+		break;
+	default:
+		ret |= 16;
+	}
+
+	if (ret)
+		fprintf(stderr, "FAILED (status %x)\n", ret);
+
+	return ret;
+}