3 files changed, 23 insertions, 4 deletions
diff --git a/lib/lib.c b/lib/lib.c
index 2a4cd8c5..2ac5c74c 100644
--- a/lib/lib.c
+++ b/lib/lib.c
@@ -478,14 +478,11 @@ off_t fdlength(int fd)
   if (!fstat(fd, &st) && S_ISREG(st.st_mode)) return st.st_size;
 
   // If the ioctl works for this, return it.
-  if (ioctl(fd, BLKGETSIZE64, &size) >= 0) return size<<9;
+  if (get_block_device_size(fd, &size)) return size<<9;
 
   // If not, do a binary search for the last location we can read.  (Some
   // block devices don't do BLKGETSIZE right.)  This should probably have
   // a CONFIG option...
-
-  // If not, do a binary search for the last location we can read.
-
   old = lseek(fd, 0, SEEK_CUR);
   do {
     char temp;
diff --git a/lib/portability.c b/lib/portability.c
index 28aaf824..145ac474 100644
--- a/lib/portability.c
+++ b/lib/portability.c
@@ -575,3 +575,23 @@ char *fs_type_name(struct statfs *statfs)
   return s;
 #endif
 }
+
+#if defined(__APPLE__)
+#include <sys/disk.h>
+int get_block_device_size(int fd, unsigned long long* size)
+{
+  unsigned long block_size, block_count;
+
+  if (!ioctl(fd, DKIOCGETBLOCKSIZE, &block_size) &&
+      !ioctl(fd, DKIOCGETBLOCKCOUNT, &block_count)) {
+    *size = block_count * block_size;
+    return 1;
+  }
+  return 0;
+}
+#elif defined(__linux__)
+int get_block_device_size(int fd, unsigned long long* size)
+{
+  return (ioctl(fd, BLKGETSIZE64, &size) >= 0);
+}
+#endif
diff --git a/lib/portability.h b/lib/portability.h
index 76790f4d..acc32fd4 100644
--- a/lib/portability.h
+++ b/lib/portability.h
@@ -359,3 +359,5 @@ int dev_major(int dev);
 int dev_makedev(int major, int minor);
 
 char *fs_type_name(struct statfs *statfs);
+
+int get_block_device_size(int fd, unsigned long long *size);