Use volume UUIDs on macOS

Author: hatzka-nezumi

Makefile.am

@@ -3,6 +3,12 @@ check_PROGRAMS = mktest mkstream
 
 AM_CPPFLAGS = -DSYSCONFDIR="\"${sysconfdir}\""
 
+if HAVE_DISK_ARBITRATION
+snapraid_LDFLAGS = -framework CoreFoundation -framework DiskArbitration
+mktest_LDFLAGS = -framework CoreFoundation -framework DiskArbitration
+mkstream_LDFLAGS = -framework CoreFoundation -framework DiskArbitration
+endif
+
 snapraid_SOURCES = \
 	raid/raid.c \
 	raid/check.c \

cmdline/mingw.c

@@ -1693,8 +1693,10 @@ int windows_readlink(const char* file, char* buffer, size_t size)
 	return len;
 }
 
-int devuuid(uint64_t device, char* uuid, size_t uuid_size)
+int devuuid(uint64_t device, const char* path, char* uuid, size_t uuid_size)
 {
+	(void)path;
+
 	/* just use the volume serial number returned in the device parameter */
 	snprintf(uuid, uuid_size, "%08x", (unsigned)device);
 

cmdline/portable.h

@@ -238,6 +238,11 @@
 #include <execinfo.h>
 #endif
 
+#ifdef __APPLE__
+#include <CoreFoundation/CoreFoundation.h>
+#include <DiskArbitration/DiskArbitration.h>
+#endif
+
 /**
  * Enable thread use.
  */
@@ -338,7 +343,7 @@ static inline int hardlink(const char* a, const char* b)
  * Get the device UUID.
  * Return 0 on success.
  */
-int devuuid(uint64_t device, char* uuid, size_t size);
+int devuuid(uint64_t device, const char* path, char* uuid, size_t size);
 
 /**
  * Physical offset not yet read.

cmdline/state.c

@@ -948,7 +948,7 @@ void state_config(struct snapraid_state* state, const char* path, const char* co
 					dev = st.st_dev;
 
 					/* read the uuid, if unsupported use an empty one */
-					if (devuuid(dev, uuid, sizeof(uuid)) != 0) {
+					if (devuuid(dev, dir, uuid, sizeof(uuid)) != 0) {
 						*uuid = 0;
 					}
 
@@ -1450,7 +1450,8 @@ static void state_map(struct snapraid_state* state)
 				char uuid[UUID_MAX];
 				int ret;
 
-				ret = devuuid(state->parity[l].split_map[s].device, uuid, sizeof(uuid));
+				ret = devuuid(state->parity[l].split_map[s].device, state->parity[l].split_map[s].path, uuid, sizeof(uuid));
+
 				if (ret != 0) {
 					/* uuid not available, just ignore */
 					continue;

cmdline/unix.c

@@ -512,8 +512,54 @@ static int devuuid_blkid(uint64_t device, char* uuid, size_t uuid_size)
 }
 #endif
 
-int devuuid(uint64_t device, char* uuid, size_t uuid_size)
+#ifdef __APPLE__
+static int devuuid_darwin(const char* path, char* uuid, size_t uuid_size) 
 {
+	CFStringRef path_apple = CFStringCreateWithCString(kCFAllocatorDefault, path, kCFStringEncodingUTF8);
+	DASessionRef session = DASessionCreate(kCFAllocatorDefault);
+
+	CFURLRef path_appler = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, path_apple, kCFURLPOSIXPathStyle, false);
+	DADiskRef disk;
+	do {
+		disk = DADiskCreateFromVolumePath(kCFAllocatorDefault, session, path_appler);
+		if (disk) {
+			CFRelease(path_appler);
+			break;
+		} else {
+			CFURLRef parent_path_appler = CFURLCreateCopyDeletingLastPathComponent(kCFAllocatorDefault, path_appler);
+			CFRelease(path_appler);
+			path_appler = parent_path_appler;
+		}
+	} while (true); // This is guaranteed to succeed eventually because it'll hit `/`.
+	
+	CFDictionaryRef description = DADiskCopyDescription(disk);
+	CFUUIDRef uuid_apple = CFDictionaryGetValue(description, kDADiskDescriptionVolumeUUIDKey);
+	CFStringRef uuid_string = CFUUIDCreateString(kCFAllocatorDefault, uuid_apple);
+	bool success = CFStringGetCString(uuid_string, uuid, uuid_size, kCFStringEncodingUTF8);
+	CFRelease(uuid_string);
+	CFRelease(description);
+	CFRelease(disk);
+	CFRelease(session);
+	CFRelease(path_apple);
+
+	if (success) {
+		return 0;
+	} else {
+		return 1;
+	}
+}
+#endif
+
+int devuuid(uint64_t device, const char* path, char* uuid, size_t uuid_size)
+{
+	(void)path;
+	(void)device;
+
+#ifdef __APPLE__
+	if (devuuid_darwin(path, uuid, uuid_size) == 0)
+		return 0;
+#endif
+
 #if HAVE_LINUX_DEVICE
 	/* if the major is the null device */
 	if (major(device) == 0) {

configure.ac

@@ -241,6 +241,7 @@ AS_CASE([$host],
 	[POSIX=1]
 )
 AM_CONDITIONAL(HAVE_POSIX, [test x"$POSIX" != x])
+AM_CONDITIONAL(HAVE_DISK_ARBITRATION, [test "$(uname)" == Darwin])
 
 AC_ARG_ENABLE([profiler],
 	[AS_HELP_STRING([--enable-profiler],[enable the use of gprof for code coverage])],