Add test case for >65535 segment coredumps

A long-belated follow-up to r303099.

With feedback from:	jmmv, ngie
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D7264

tests/sys/kern/Makefile

@@ -14,6 +14,11 @@ ATF_TESTS_C+=	unix_passfd_test
 TEST_METADATA.unix_seqpacket_test+=	timeout="15"
 ATF_TESTS_C+=	waitpid_nohang
 
+ATF_TESTS_SH+=	coredump_phnum_test
+
+BINDIR=		${TESTSDIR}
+PROGS+=		coredump_phnum_helper
+
 LIBADD.ptrace_test+=			pthread
 LIBADD.unix_seqpacket_test+=		pthread
 

tests/sys/kern/coredump_phnum_helper.c

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2016, Conrad Meyer
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/mman.h>
+
+#include <err.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+/*
+ * This program is intended to create a bunch of segment mappings, then dump
+ * core.
+ */
+int
+main(int argc __unused, char **argv __unused)
+{
+	void *v;
+	unsigned i;
+
+	for (i = 0; i < UINT16_MAX + 1000; i++) {
+		/*
+		 * Alternate protections; otherwise the kernel will just extend
+		 * the adjacent same-protection previous mapping.
+		 */
+		v = mmap(NULL, PAGE_SIZE,
+		    (((i % 2) == 0) ? PROT_READ : 0) | PROT_WRITE,
+		    MAP_ANON | MAP_PRIVATE, -1, 0);
+		if (v == MAP_FAILED)
+			err(1, "mmap");
+	}
+
+	/* Dump core. */
+	abort();
+}

tests/sys/kern/coredump_phnum_test.sh

@@ -0,0 +1,90 @@
+#
+#  Copyright (c) 2016 Dell EMC Isilon
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions
+#  are met:
+#  1. Redistributions of source code must retain the above copyright
+#     notice, this list of conditions, and the following disclaimer,
+#     without modification.
+#  2. Redistributions in binary form must reproduce at minimum a disclaimer
+#     substantially similar to the "NO WARRANTY" disclaimer below
+#     ("Disclaimer") and any redistribution must be conditioned upon
+#     including a substantially similar Disclaimer requirement for further
+#     binary redistribution.
+#
+#  NO WARRANTY
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+#  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+#  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
+#  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+#  HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+#  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+#  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+#  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+#  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+#  IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+#  POSSIBILITY OF SUCH DAMAGES.
+#
+# $FreeBSD$
+
+atf_test_case coredump_phnum cleanup
+coredump_phnum_head()
+{
+	atf_set "allow_sysctl_side_effects" "1"
+	atf_set "descr" "More than 65534 segments"
+	atf_set "require.progs" "readelf procstat"
+	atf_set "require.user" "root"
+}
+coredump_phnum_body()
+{
+	# Set up core dumping
+	cat > coredump_phnum_restore_state.sh <<-EOF
+	#!/bin/sh
+	ulimit -c '$(ulimit -c)'
+	sysctl kern.coredump=$(sysctl -n kern.coredump)
+	sysctl kern.corefile='$(sysctl -n kern.corefile)'
+EOF
+	chmod +x coredump_phnum_restore_state.sh
+
+	ulimit -c unlimited
+	sysctl kern.coredump=1
+	sysctl kern.corefile="$(pwd)/coredump_phnum_helper.core"
+
+	atf_check -s signal:sigabrt "$(atf_get_srcdir)/coredump_phnum_helper"
+
+	# Check that core looks good
+	if [ ! -f coredump_phnum_helper.core ]; then
+	    atf_fail "Helper program did not dump core"
+	fi
+
+	# These magic numbers don't have any real significance.  They are just
+	# the result of running the helper program and dumping core.  The only
+	# important bit is that they're larger than 65535 (UINT16_MAX).
+	readelf -h coredump_phnum_helper.core | \
+	    atf_check -o "match:65535 \(66169\)" \
+	    grep "Number of program headers:"
+	readelf -l coredump_phnum_helper.core | \
+	    atf_check -o "match:There are 66169 program headers" \
+	    grep -1 "program headers"
+	readelf -S coredump_phnum_helper.core | \
+	    atf_check -o "match: 0000000000000001 .* 66169 " \
+	    grep -A1 "^  \[ 0\] "
+
+	procstat -v coredump_phnum_helper.core | \
+	    atf_check -o "match:66545" wc -l
+}
+coredump_phnum_cleanup()
+{
+	rm -f coredump_phnum_helper.core
+	if [ -x coredump_phnum_restore_state.sh ]; then
+		./coredump_phnum_restore_state.sh
+	fi
+	rm -f coredump_phnum_restore_state.sh
+}
+
+atf_init_test_cases()
+{
+	atf_add_test_case coredump_phnum
+}