Re: Release of version 4.14.2 of sharutils

On 12/22/2014 11:25 AM, Eric Blake wrote:
> 
> You still have a bug that needs fixing:
> 
> shar.c: In function 'walktree':
> shar.c:577:5: warning: implicit declaration of function 'basename'
> [-Wimplicit-function-declaration]
>      restore_name = basename (local_name_copy);
>      ^
> shar.c:577:18: warning: assignment makes pointer from integer without a
> cast [enabled by default]
>      restore_name = basename (local_name_copy);
>                   ^
> 
> On 32-bit cygwin, 'int' and 'void*' are the same width, so the correct
> thing happens in spite of the bad coding, and the testsuite passes; but
> on 64-bit cygwin, since 'int' is truncated, and the memory layout
> intentionally sticks heap pointers outside the first 4G, you are
> corrupting the value returned by basename by integer truncation before
> re-expansion back to a pointer, and this causes a testsuite failure:

Sure enough, this patch was sufficient to avoid the testsuite failure on
64-bit cygwin:

diff --git i/src/shar.c w/src/shar.c
index fd7cf41..47ad514 100644
--- i/src/shar.c
+++ w/src/shar.c
@@ -50,6 +50,7 @@ static const char cright_years_z[] =
 # include <limits.h>
 #endif
 #include <time.h>
+#include <libgen.h>

 #include "inttostr.h"
 #include "liballoca.h"


That said,

> basename() is non-portable, and not thread-safe; it's better to use
> gnulib's base_name() function.

I still stand by this advice; gnulib intentionally does not guarantee
<libgen.h> (and it is missing on at least mingw), because basename() is
not the right function to be using if you care about systems with drive
letters.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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