1 files changed, 22 insertions, 3 deletions

diff --git a/tools/idevicebackup.c b/tools/idevicebackup.c
index 76ae1a0..867eaad 100644
--- a/tools/idevicebackup.c
+++ b/tools/idevicebackup.c
@@ -38,6 +38,9 @@
 #define MOBILEBACKUP_SERVICE_NAME "com.apple.mobilebackup"
 #define NP_SERVICE_NAME "com.apple.mobile.notification_proxy"
 
+#define LOCK_ATTEMPTS 50
+#define LOCK_WAIT 200000
+
 static mobilebackup_client_t mobilebackup = NULL;
 static lockdownd_client_t client = NULL;
 static idevice_t phone = NULL;
@@ -873,12 +876,28 @@ int main(int argc, char *argv[])
                         afc_file_open(afc, "/com.apple.itunes.lock_sync", AFC_FOPEN_RW, &lockfile);
                 }
                 if (lockfile) {
+                        afc_error_t aerr;
                         do_post_notification(NP_SYNC_LOCK_REQUEST);
-                        if (afc_file_lock(afc, lockfile, AFC_LOCK_EX) == AFC_E_SUCCESS) {
-                                do_post_notification(NP_SYNC_DID_START);
-                        } else {
+                        for (i = 0; i < LOCK_ATTEMPTS; i++) {
+                                aerr = afc_file_lock(afc, lockfile, AFC_LOCK_EX);
+                                if (aerr == AFC_E_SUCCESS) {
+                                        do_post_notification(NP_SYNC_DID_START);
+                                        break;
+                                } else if (aerr == AFC_E_OP_WOULD_BLOCK) {
+                                        usleep(LOCK_WAIT);
+                                        continue;
+                                } else {
+                                        fprintf(stderr, "ERROR: could not lock file! error code: %d\n", aerr);
+                                        afc_file_close(afc, lockfile);
+                                        lockfile = 0;
+                                        cmd = CMD_LEAVE;
+                                }
+                        }
+                        if (i == LOCK_ATTEMPTS) {
+                                fprintf(stderr, "ERROR: timeout while locking for sync\n");
                                 afc_file_close(afc, lockfile);
                                 lockfile = 0;
+                                cmd = CMD_LEAVE;
                         }
                 }