Added compiling target Android support

Makefile

@@ -215,6 +215,7 @@ objects = \
 	kernel-shared/uuid-tree.o	\
 	kernel-shared/volumes.o	\
 	kernel-shared/zoned.o	\
+	pthread/btrfs_pthread.o	\
 	common/array.o		\
 	common/cpu-utils.o	\
 	common/device-scan.o	\
@@ -292,7 +293,7 @@ tune_objects = tune/main.o tune/seeding.o tune/change-uuid.o tune/change-metadat
 all_objects = $(objects) $(cmds_objects) $(libbtrfs_objects) $(convert_objects) \
 	      $(mkfs_objects) $(image_objects) $(tune_objects) $(libbtrfsutil_objects)
 
-tags_files = $(addsuffix /*.[ch], . check cmds common convert crypto image include mkfs tune \
+tags_files = $(addsuffix /*.[ch], . check cmds common convert crypto image include mkfs pthread tune \
 	       kernel-lib kernel-shared kernel-shared/uapi \
 	       libbtrfs libbtrfsutil libbtrfsutil/python tests)
 
@@ -928,6 +929,7 @@ clean: $(CLEANDIRS)
 		libbtrfs/*.o libbtrfs/.deps/*.o.d \
 		libbtrfsutil/*.o libbtrfsutil/.deps/*.o.d \
 		mkfs/*.o mkfs/.deps/*.o.d \
+		pthread/*.o pthread/.deps/*.o.d \
 		tune/*.o tune/.deps/*.o.d
 	$(Q)$(RM) -fd -- .deps */.deps */*/.deps
 	@echo "Cleaning test targets"

cmds/rescue-chunk-recover.c

@@ -22,7 +22,7 @@
 #include <stdlib.h>
 #include <fcntl.h>
 #include <unistd.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include <errno.h>
 #include <stddef.h>
 #include <string.h>

cmds/scrub.c

@@ -27,7 +27,7 @@
 #include <poll.h>
 #include <fcntl.h>
 #include <unistd.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include <ctype.h>
 #include <signal.h>
 #include <stdarg.h>

cmds/send.c

@@ -21,7 +21,7 @@
 #include <stdbool.h>
 #include <unistd.h>
 #include <fcntl.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include <getopt.h>
 #include <limits.h>
 #include <errno.h>

common/task-utils.c

@@ -15,7 +15,7 @@
  */
 
 #include <sys/timerfd.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include <stdlib.h>
 #include <unistd.h>
 #include <time.h>

common/task-utils.h

@@ -19,7 +19,7 @@
 
 #include "kerncompat.h"
 #include <time.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 
 struct periodic_info {
 	int timer_fd;

convert/main.c

@@ -88,7 +88,7 @@
 #include <fcntl.h>
 #include <unistd.h>
 #include <getopt.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include <stdbool.h>
 #include <errno.h>
 #include <limits.h>

convert/source-ext2.c

@@ -20,7 +20,7 @@
 #include <sys/stat.h>
 #include <linux/limits.h>
 #include <errno.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>

convert/source-fs.h

@@ -19,7 +19,7 @@
 
 #include "kerncompat.h"
 #include <sys/types.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include "kernel-shared/uapi/btrfs_tree.h"
 #include "convert/common.h"
 

image/image-create.c

@@ -23,7 +23,7 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include <zlib.h>
 #include "kernel-lib/list.h"
 #include "kernel-lib/rbtree.h"

image/image-restore.c

@@ -25,7 +25,7 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include <zlib.h>
 #include "kernel-lib/list.h"
 #include "kernel-lib/rbtree.h"

image/metadump.h

@@ -18,7 +18,7 @@
 #define __BTRFS_IMAGE_METADUMP_H__
 
 #include "kerncompat.h"
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include "kernel-lib/list.h"
 #include "kernel-lib/sizes.h"
 #include "kernel-shared/ctree.h"

mkfs/main.c

@@ -26,7 +26,7 @@
 #include <errno.h>
 #include <stdbool.h>
 #include <string.h>
-#include <pthread.h>
+#include "pthread/btrfs_pthread.h"
 #include <uuid/uuid.h>
 #include <blkid/blkid.h>
 #include "kernel-lib/list.h"

pthread/btrfs_pthread.c

@@ -0,0 +1,40 @@
+#include "include/config.h"
+
+#ifdef __ANDROID__
+
+/* Workaround for `pthread_cancel()` in Android, using `pthread_kill()` instead,
+ * as Android NDK does not support `pthread_cancel()`.
+ */
+
+#include <string.h>
+#include <signal.h>
+#include "btrfs_pthread.h"
+
+int pthread_setcanceltype(int type, int *oldtype) { return 0; }
+int pthread_setcancelstate(int state, int *oldstate) { return 0; }
+int pthread_cancel(pthread_t thread_id) {
+	int status;
+	if ((status = btrfs_set_thread_exit_handler()) == 0) {
+		status = pthread_kill(thread_id, SIGUSR1);
+	}
+	return status;
+}
+
+void btrfs_thread_exit_handler(int sig) {
+	pthread_exit(0);
+}
+
+int btrfs_set_thread_exit_handler() {
+	int rc;
+	struct sigaction actions;
+
+	memset(&actions, 0, sizeof(actions));
+	sigemptyset(&actions.sa_mask);
+	actions.sa_flags = 0;
+	actions.sa_handler = btrfs_thread_exit_handler;
+
+	rc = sigaction(SIGUSR1, &actions, NULL);
+	return rc;
+}
+
+#endif

pthread/btrfs_pthread.h

@@ -0,0 +1,24 @@
+#include "include/config.h"
+
+#include <pthread.h>
+
+#ifdef __ANDROID__
+
+/* Adding missing `pthread` related definitions in Android.
+ */
+
+#define PTHREAD_CANCELED ((void *) -1)
+
+#define PTHREAD_CANCEL_DEFERRED 0
+#define PTHREAD_CANCEL_ASYNCHRONOUS 0
+#define PTHREAD_CANCEL_ENABLE 0
+#define PTHREAD_CANCEL_DISABLE 0
+
+int pthread_setcanceltype(int type, int *oldtype);
+int pthread_setcancelstate(int state, int *oldstate);
+int pthread_cancel(pthread_t thread_id);
+
+int btrfs_set_thread_exit_handler();
+void btrfs_thread_exit_handler(int sig);
+
+#endif

pthread/pthread.sym

@@ -0,0 +1,8 @@
+PTHREAD_0.1 {
+global:
+	pthread_setcanceltype;			/* used */
+	pthread_setcancelstate;			/* used */
+	pthread_cancel;				/* used */
+local:
+	*;
+};