[PATCH v4] erofs-utils: support 128-bit filesystem UUID

[Gao Xiang]

Complete filesystem UUID feature on userspace side.

Cc: Chao Yu <yuchao0 at huawei.com>
Cc: Li Guifu <bluce.liguifu at huawei.com>
Signed-off-by: Gao Xiang <hsiangkao at aol.com>
---
changes since v3:
 - fix configure.ac script and fully passed travis CI
   https://travis-ci.org/erofs/erofs-utils-ci/builds/611213382

 configure.ac             | 41 ++++++++++++++++++++++++++++++++++++++++
 include/erofs/internal.h |  1 +
 mkfs/Makefile.am         |  3 ++-
 mkfs/main.c              | 20 ++++++++++++++++++++
 4 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index a93767f..c7dbe0e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -20,6 +20,15 @@ AC_PROG_INSTALL
 
 LT_INIT
 
+# Test presence of pkg-config
+AC_MSG_CHECKING([pkg-config m4 macros])
+if test m4_ifdef([PKG_CHECK_MODULES], [yes], [no]) = "yes"; then
+  AC_MSG_RESULT([yes]);
+else
+  AC_MSG_RESULT([no]);
+  AC_MSG_ERROR([pkg-config is required. See pkg-config.freedesktop.org])
+fi
+
 dnl EROFS_UTILS_PARSE_DIRECTORY
 dnl Input:  $1 = a string to a relative or absolute directory
 dnl Output: $2 = the variable to set with the absolute directory
@@ -54,6 +63,10 @@ AC_ARG_ENABLE(lz4,
    [AS_HELP_STRING([--disable-lz4], [disable LZ4 compression support @<:@default=enabled@:>@])],
    [enable_lz4="$enableval"], [enable_lz4="yes"])
 
+AC_ARG_WITH(uuid,
+   [AS_HELP_STRING([--without-uuid],
+      [Ignore presence of libuuid and disable uuid support @<:@default=enabled@:>@])])
+
 # Checks for libraries.
 # Use customized LZ4 library path when specified.
 AC_ARG_WITH(lz4-incdir,
@@ -123,6 +136,30 @@ AC_CHECK_DECL(lseek64,[AC_DEFINE(HAVE_LSEEK64_PROTOTYPE, 1,
 # Checks for library functions.
 AC_CHECK_FUNCS([fallocate gettimeofday memset realpath strdup strerror strrchr strtoull])
 
+# Configure libuuid
+AS_IF([test "x$with_uuid" != "xno"], [
+  PKG_CHECK_MODULES([libuuid], [uuid])
+  # Paranoia: don't trust the result reported by pkgconfig before trying out
+  saved_LIBS="$LIBS"
+  saved_CPPFLAGS=${CPPFLAGS}
+  CPPFLAGS="${libuuid_CFLAGS} ${CPPFLAGS}"
+  LIBS="${libuuid_LIBS} $LIBS"
+  AC_MSG_CHECKING([libuuid usability])
+  AC_TRY_LINK([
+#include <uuid.h>
+], [
+uuid_t tmp;
+
+uuid_generate(tmp);
+return 0;
+], [have_uuid="yes"
+    AC_MSG_RESULT([yes])], [
+    have_uuid="no"
+    AC_MSG_RESULT([no])
+    AC_MSG_ERROR([libuuid doesn't work properly])])
+  LIBS="${saved_LIBS}"
+  CPPFLAGS="${saved_CPPFLAGS}"], [have_uuid="no"])
+
 # Configure lz4
 test -z $LZ4_LIBS && LZ4_LIBS='-llz4'
 
@@ -169,6 +206,10 @@ if test "x$enable_lz4" = "xyes"; then
   CFLAGS=${saved_CPPFLAGS}
 fi
 
+if test "x$have_uuid" = "xyes"; then
+  AC_DEFINE([HAVE_LIBUUID], 1, [Define to 1 if libuuid is found])
+fi
+
 AM_CONDITIONAL([ENABLE_LZ4], [test "x${have_lz4}" = "xyes"])
 AM_CONDITIONAL([ENABLE_LZ4HC], [test "x${have_lz4hc}" = "xyes"])
 
diff --git a/include/erofs/internal.h b/include/erofs/internal.h
index 9e2bb9c..e13adda 100644
--- a/include/erofs/internal.h
+++ b/include/erofs/internal.h
@@ -56,6 +56,7 @@ struct erofs_sb_info {
 	u32 feature_incompat;
 	u64 build_time;
 	u32 build_time_nsec;
+	u8 uuid[16];
 };
 
 /* global sbi */
diff --git a/mkfs/Makefile.am b/mkfs/Makefile.am
index 257f864..9ce06d6 100644
--- a/mkfs/Makefile.am
+++ b/mkfs/Makefile.am
@@ -3,7 +3,8 @@
 
 AUTOMAKE_OPTIONS = foreign
 bin_PROGRAMS     = mkfs.erofs
+AM_CPPFLAGS = ${libuuid_CFLAGS}
 mkfs_erofs_SOURCES = main.c
 mkfs_erofs_CFLAGS = -Wall -Werror -I$(top_srcdir)/include
-mkfs_erofs_LDADD = $(top_builddir)/lib/liberofs.la
+mkfs_erofs_LDADD = $(top_builddir)/lib/liberofs.la ${libuuid_LIBS}
 
diff --git a/mkfs/main.c b/mkfs/main.c
index 9187c43..7493a48 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -22,6 +22,10 @@
 #include "erofs/compress.h"
 #include "erofs/xattr.h"
 
+#ifdef HAVE_LIBUUID
+#include <uuid/uuid.h>
+#endif
+
 #define EROFS_SUPER_END (EROFS_SUPER_OFFSET + sizeof(struct erofs_super_block))
 
 static struct option long_options[] = {
@@ -234,6 +238,7 @@ int erofs_mkfs_update_super_block(struct erofs_buffer_head *bh,
 	*blocks         = erofs_mapbh(NULL, true);
 	sb.blocks       = cpu_to_le32(*blocks);
 	sb.root_nid     = cpu_to_le16(root_nid);
+	memcpy(sb.uuid, sbi.uuid, sizeof(sb.uuid));
 
 	buf = calloc(sb_blksize, 1);
 	if (!buf) {
@@ -305,6 +310,20 @@ static int erofs_mkfs_superblock_csum_set(void)
 	return 0;
 }
 
+static void erofs_mkfs_generate_uuid(void)
+{
+	char uuid_str[37] = "not available";
+
+#ifdef HAVE_LIBUUID
+	do {
+		uuid_generate(sbi.uuid);
+	} while (uuid_is_null(sbi.uuid));
+
+	uuid_unparse_lower(sbi.uuid, uuid_str);
+#endif
+	erofs_info("filesystem UUID: %s", uuid_str);
+}
+
 int main(int argc, char **argv)
 {
 	int err = 0;
@@ -376,6 +395,7 @@ int main(int argc, char **argv)
 		goto exit;
 	}
 
+	erofs_mkfs_generate_uuid();
 	erofs_inode_manager_init();
 
 	err = erofs_build_shared_xattrs_from_path(cfg.c_src_path);
-- 
2.17.1