From: Thomas Weißschuh <thomas@t-8ch.de>
Date: Thu, 15 Dec 2022 13:32:31 +0000 (+0000)
Subject: mkswap: create files with specific endianness
X-Git-Tag: v2.39-rc1~364^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2a80192f027eed952c8ecee68ecc9676971f31db;p=thirdparty%2Futil-linux.git

mkswap: create files with specific endianness
---

diff --git a/disk-utils/mkswap.8.adoc b/disk-utils/mkswap.8.adoc
index 0a25a2dbed..904467d772 100644
--- a/disk-utils/mkswap.8.adoc
+++ b/disk-utils/mkswap.8.adoc
@@ -70,6 +70,9 @@ generate a new randomly-generated UUID
 *time*;;
 generate a new time-based UUID
 
+*-e*, *--endianness* _ENDIANNESS_::
+Specify the _ENDIANNESS_ to use, valid arguments are *native*, *little* or *big*. The default is *native*.
+
 *-v*, *--swapversion 1*::
 Specify the swap-space version. (This option is currently pointless, as the old *-v 0* option has become obsolete and now only *-v 1* is supported. The kernel has not supported v0 swap-space format since 2.5.22 (June 2002). The new version v1 is supported since 2.1.117 (August 1998).)
 
diff --git a/disk-utils/mkswap.c b/disk-utils/mkswap.c
index d14f24901c..6f6d3048a3 100644
--- a/disk-utils/mkswap.c
+++ b/disk-utils/mkswap.c
@@ -42,6 +42,7 @@
 #include "closestream.h"
 #include "ismounted.h"
 #include "optutils.h"
+#include "bitops.h"
 
 #ifdef HAVE_LIBUUID
 # include <uuid.h>
@@ -55,6 +56,12 @@
 
 #define SELINUX_SWAPFILE_TYPE	"swapfile_t"
 
+enum ENDIANNESS {
+	ENDIANNESS_NATIVE,
+	ENDIANNESS_LITTLE,
+	ENDIANNESS_BIG,
+};
+
 struct mkswap_control {
 	struct swap_header_v1_2	*hdr;		/* swap header */
 	void			*signature_page;/* buffer with swap header */
@@ -75,12 +82,24 @@ struct mkswap_control {
 
 	size_t			nbad_extents;
 
+	enum ENDIANNESS         endianness;
+
 	unsigned int		check:1,	/* --check */
 				verbose:1,      /* --verbose */
 				quiet:1,        /* --quiet */
 				force:1;	/* --force */
 };
 
+static uint32_t cpu32_to_endianness(uint32_t v, enum ENDIANNESS e)
+{
+	switch (e) {
+		case ENDIANNESS_NATIVE: return v;
+		case ENDIANNESS_LITTLE: return cpu_to_le32(v);
+		case ENDIANNESS_BIG: return cpu_to_be32(v);
+	}
+	abort();
+}
+
 static void init_signature_page(struct mkswap_control *ctl)
 {
 	const int kernel_pagesize = getpagesize();
@@ -172,6 +191,9 @@ static void __attribute__((__noreturn__)) usage(void)
 	fputs(_(" -L, --label LABEL         specify label\n"), out);
 	fputs(_(" -v, --swapversion NUM     specify swap-space version number\n"), out);
 	fputs(_(" -U, --uuid UUID           specify the uuid to use\n"), out);
+	fprintf(out,
+	      _(" -e, --endianness=<value>  specify the endianness to use "
+	                                    "(%s, %s or %s)\n"), "native", "little", "big");
 	fputs(_("     --verbose             verbose output\n"), out);
 
 	fprintf(out,
@@ -458,7 +480,7 @@ static void write_header_to_device(struct mkswap_control *ctl)
 
 int main(int argc, char **argv)
 {
-	struct mkswap_control ctl = { .fd = -1 };
+	struct mkswap_control ctl = { .fd = -1, .endianness = ENDIANNESS_NATIVE };
 	int c, permMask;
 	uint64_t sz;
 	int version = SWAP_VERSION;
@@ -479,6 +501,7 @@ int main(int argc, char **argv)
 		{ "label",       required_argument, NULL, 'L' },
 		{ "swapversion", required_argument, NULL, 'v' },
 		{ "uuid",        required_argument, NULL, 'U' },
+		{ "endianness",  required_argument, NULL, 'e' },
 		{ "version",     no_argument,       NULL, 'V' },
 		{ "help",        no_argument,       NULL, 'h' },
 		{ "lock",        optional_argument, NULL, OPT_LOCK },
@@ -497,7 +520,7 @@ int main(int argc, char **argv)
 	textdomain(PACKAGE);
 	close_stdout_atexit();
 
-	while((c = getopt_long(argc, argv, "cfp:qL:v:U:Vh", longopts, NULL)) != -1) {
+	while((c = getopt_long(argc, argv, "cfp:qL:v:U:e:Vh", longopts, NULL)) != -1) {
 
 		err_exclusive_options(c, longopts, excl, excl_st);
 
@@ -531,6 +554,18 @@ int main(int argc, char **argv)
 				program_invocation_short_name);
 #endif
 			break;
+		case 'e':
+			if (strcmp(optarg, "native") == 0) {
+				ctl.endianness = ENDIANNESS_NATIVE;
+			} else if (strcmp(optarg, "little") == 0) {
+				ctl.endianness = ENDIANNESS_LITTLE;
+			} else if (strcmp(optarg, "big") == 0) {
+				ctl.endianness = ENDIANNESS_BIG;
+			} else {
+				errx(EXIT_FAILURE,
+					_("invalid endianness %s is not supported"), optarg);
+			}
+			break;
 		case 'V':
 			print_version(EXIT_SUCCESS);
 			break;
@@ -637,9 +672,9 @@ int main(int argc, char **argv)
 	wipe_device(&ctl);
 
 	assert(ctl.hdr);
-	ctl.hdr->version = version;
-	ctl.hdr->last_page = ctl.npages - 1;
-	ctl.hdr->nr_badpages = ctl.nbadpages;
+	ctl.hdr->version = cpu32_to_endianness(version, ctl.endianness);
+	ctl.hdr->last_page = cpu32_to_endianness(ctl.npages - 1, ctl.endianness);
+	ctl.hdr->nr_badpages = cpu32_to_endianness(ctl.nbadpages, ctl.endianness);
 
 	if ((ctl.npages - MIN_GOODPAGES) < ctl.nbadpages)
 		errx(EXIT_FAILURE, _("Unable to set up swap-space: unreadable"));
diff --git a/tests/ts/mkswap/mkswap b/tests/ts/mkswap/mkswap
index 2cb999a277..fa4856b719 100755
--- a/tests/ts/mkswap/mkswap
+++ b/tests/ts/mkswap/mkswap
@@ -28,26 +28,38 @@ ts_check_test_command "$TS_HELPER_SYSINFO"
 ts_check_prog "xz"
 ts_check_prog "cmp"
 
-BYTE_ORDER="$("$TS_HELPER_SYSINFO" byte-order)"
 UUID=4c08e1cd-3c82-46bf-a55b-0c3270d6dfeb
 
 for PAGESIZE in 4096 8192; do
-	name="${BYTE_ORDER}-${PAGESIZE}"
-	outimg="$TS_OUTDIR/${name}.img"
-	origimg="$TS_OUTDIR/${name}.img.orig"
+	for ENDIANNESS in native little big; do
+		case "$ENDIANNESS" in 
+			native) BYTE_ORDER="$("$TS_HELPER_SYSINFO" byte-order)";;
+			little) BYTE_ORDER=LE;;
+			big) BYTE_ORDER=BE;;
+		esac
 
-	ts_init_subtest $name
+		if [ "$ENDIANNESS" == "native" ]; then
+			name="NATIVE-${PAGESIZE}"
+		else
+			name="${BYTE_ORDER}-${PAGESIZE}"
+		fi
+		outimg="$TS_OUTDIR/${BYTE_ORDER}-${PAGESIZE}.img"
+		origimg="$TS_OUTDIR/${BYTE_ORDER}-${PAGESIZE}.img.orig"
 
-	rm -f "$outimg"
-	truncate -s $(( PAGESIZE * 10 )) "$outimg" > $TS_ERRLOG 2>&1
+		ts_init_subtest $name
 
-	"$TS_CMD_MKSWAP" -q -L label -U "$UUID" -p "$PAGESIZE" "$outimg" \
-		> "$TS_OUTPUT" 2> "$TS_ERRLOG" || ts_log "mkswap failed"
-	xz -dc "$TS_SELF/${name}.img.xz" > "$origimg"
+		rm -f "$outimg"
+		truncate -s $(( PAGESIZE * 10 )) "$outimg" > $TS_ERRLOG 2>&1
 
-	cmp "$origimg" "$outimg" > "$TS_ERRLOG" 2>&1
+		"$TS_CMD_MKSWAP" -q -L label -U "$UUID" -e "$ENDIANNESS" -p "$PAGESIZE" "$outimg" \
+			> "$TS_OUTPUT" 2>/dev/null \
+			|| ts_log "mkswap failed"
+		xz -dc "$TS_SELF/${BYTE_ORDER}-${PAGESIZE}.img.xz" > "$origimg"
 
-	ts_finalize_subtest
+		cmp "$origimg" "$outimg" > "$TS_ERRLOG" 2>&1
+
+		ts_finalize_subtest
+	done
 done
 
 ts_finalize