generic: test invalid swap file activation

Swap files cannot have holes, and they must at least two pages.
swapon(8) and mkswap(8) have stricter restrictions, so add versions
of those commands without any restrictions.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>

.gitignore

@@ -92,6 +92,7 @@
 /src/lstat64
 /src/makeextents
 /src/metaperf
+/src/mkswap
 /src/mmapcat
 /src/multi_open_unlink
 /src/nametest
@@ -111,6 +112,7 @@
 /src/seek_sanity_test
 /src/stale_handle
 /src/stat_test
+/src/swapon
 /src/t_access_root
 /src/t_dir_offset
 /src/t_dir_offset2

src/Makefile

@@ -26,7 +26,7 @@ LINUX_TARGETS = xfsctl bstat t_mtab getdevicesize preallo_rw_pattern_reader \
 	renameat2 t_getcwd e4compact test-nextquota punch-alternating \
 	attr-list-by-handle-cursor-test listxattr dio-interleaved t_dir_type \
 	dio-invalidate-cache stat_test t_encrypted_d_revalidate \
-	attr_replace_test
+	attr_replace_test swapon mkswap
 
 SUBDIRS = log-writes perf
 

src/mkswap.c

@@ -0,0 +1,83 @@
+/* mkswap(8) without any sanity checks */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+struct swap_header {
+	char		bootbits[1024];
+	uint32_t	version;
+	uint32_t	last_page;
+	uint32_t	nr_badpages;
+	unsigned char	sws_uuid[16];
+	unsigned char	sws_volume[16];
+	uint32_t	padding[117];
+	uint32_t	badpages[1];
+};
+
+int main(int argc, char **argv)
+{
+	struct swap_header *hdr;
+	FILE *file;
+	struct stat st;
+	long page_size;
+	int ret;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s PATH\n", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	page_size = sysconf(_SC_PAGESIZE);
+	if (page_size == -1) {
+		perror("sysconf");
+		return EXIT_FAILURE;
+	}
+
+	hdr = calloc(1, page_size);
+	if (!hdr) {
+		perror("calloc");
+		return EXIT_FAILURE;
+	}
+
+	file = fopen(argv[1], "r+");
+	if (!file) {
+		perror("fopen");
+		free(hdr);
+		return EXIT_FAILURE;
+	}
+
+	ret = fstat(fileno(file), &st);
+	if (ret) {
+		perror("fstat");
+		free(hdr);
+		fclose(file);
+		return EXIT_FAILURE;
+	}
+
+	hdr->version = 1;
+	hdr->last_page = st.st_size / page_size - 1;
+	memset(&hdr->sws_uuid, 0x99, sizeof(hdr->sws_uuid));
+	memcpy((char *)hdr + page_size - 10, "SWAPSPACE2", 10);
+
+	if (fwrite(hdr, page_size, 1, file) != 1) {
+		perror("fwrite");
+		free(hdr);
+		fclose(file);
+		return EXIT_FAILURE;
+	}
+
+	if (fclose(file) == EOF) {
+		perror("fwrite");
+		free(hdr);
+		return EXIT_FAILURE;
+	}
+
+	free(hdr);
+
+	return EXIT_SUCCESS;
+}

src/swapon.c

@@ -0,0 +1,24 @@
+/* swapon(8) without any sanity checks; simply calls swapon(2) directly. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/swap.h>
+
+int main(int argc, char **argv)
+{
+	int ret;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s PATH\n", argv[0]);
+		return EXIT_FAILURE;
+	}
+
+	ret = swapon(argv[1], 0);
+	if (ret) {
+		perror("swapon");
+		return EXIT_FAILURE;
+	}
+
+	return EXIT_SUCCESS;
+}

tests/generic/495

@@ -0,0 +1,77 @@
+#! /bin/bash
+# FS QA Test 495
+#
+# Test invalid swap files.
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2018 Facebook.  All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#-----------------------------------------------------------------------
+#
+
+seq=`basename $0`
+seqres=$RESULT_DIR/$seq
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+_cleanup()
+{
+	cd /
+	rm -f $tmp.*
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+_supported_fs generic
+_supported_os Linux
+_require_scratch_swapfile
+_require_test_program mkswap
+_require_test_program swapon
+
+_scratch_mkfs >> $seqres.full 2>&1
+_scratch_mount
+
+echo "File with holes"
+# We can't use _format_swapfile because we're using our custom mkswap and
+# swapon.
+touch "$SCRATCH_MNT/swap"
+$CHATTR_PROG +C "$SCRATCH_MNT/swap" >> $seqres.full 2>&1
+chmod 0600 "$SCRATCH_MNT/swap"
+$XFS_IO_PROG -c "truncate $(($(get_page_size) * 10))" "$SCRATCH_MNT/swap"
+"$here/src/mkswap" "$SCRATCH_MNT/swap"
+"$here/src/swapon" "$SCRATCH_MNT/swap"
+swapoff "$SCRATCH_MNT/swap" >/dev/null 2>&1
+
+echo "Empty swap file (only swap header)"
+rm -f "$SCRATCH_MNT/swap"
+touch "$SCRATCH_MNT/swap"
+$CHATTR_PROG +C "$SCRATCH_MNT/swap" >> $seqres.full 2>&1
+chmod 0600 "$SCRATCH_MNT/swap"
+_pwrite_byte 0x61 0 $(get_page_size) "$SCRATCH_MNT/swap" >> $seqres.full
+"$here/src/mkswap" "$SCRATCH_MNT/swap"
+"$here/src/swapon" "$SCRATCH_MNT/swap"
+swapoff "$SCRATCH_MNT/swap" >/dev/null 2>&1
+
+status=0
+exit

tests/generic/495.out

@@ -0,0 +1,5 @@
+QA output created by 495
+File with holes
+swapon: Invalid argument
+Empty swap file (only swap header)
+swapon: Invalid argument

tests/generic/group

@@ -496,3 +496,4 @@
 492 auto quick
 493 auto quick swap
 494 auto quick swap
+495 auto quick swap