X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=lib%2Fsystem.h;h=e7f531c8836eccbf9705866ca3a24220c9b636ac;hb=HEAD;hp=2deb585b41baf7b16b27d79cfe8f7a8b5912995e;hpb=138fc7e67e3d9845cd7d81aad0e9c7724784f9b9;p=debian%2Ftar

diff --git a/lib/system.h b/lib/system.h
index 2deb585b..e7f531c8 100644
--- a/lib/system.h
+++ b/lib/system.h
@@ -389,9 +389,16 @@ extern int errno;
 # define ST_NBLOCKSIZE 512
 #endif
 
+/* Network Appliance file systems store small files directly in the
+   inode if st_size <= 64; in this case the number of blocks can be
+   zero.  Perhaps other file systems have similar problems; so,
+   somewhat arbitrarily, do not consider a file to be sparse if
+   it has no blocks but st_size < ST_NBLOCKSIZE.  */
 #define ST_IS_SPARSE(st)                                  \
   (ST_NBLOCKS (st)                                        \
-    < ((st).st_size / ST_NBLOCKSIZE + ((st).st_size % ST_NBLOCKSIZE != 0)))
+   < ((st).st_size / ST_NBLOCKSIZE			  \
+      + ((st).st_size % ST_NBLOCKSIZE != 0		  \
+	 && (st).st_size / ST_NBLOCKSIZE != 0)))
 
 /* Declare standard functions.  */
 
@@ -471,8 +478,11 @@ char *getenv ();
 # define SET_BINARY_MODE(arc)
 # define ERRNO_IS_EACCES 0
 # define TTY_NAME "/dev/tty"
-# define sys_reset_uid_gid() \
- do { setuid (getuid ()); setgid (getgid ()); } while (0)
+# define sys_reset_uid_gid()					\
+  do {								\
+    if (! (setuid (getuid ()) == 0 && setgid (getgid ()) == 0)) \
+      abort ();							\
+  } while (0)
 #endif
 
 #if XENIX