Re: [PATCH v4 2/5] t5000: test tar files that overflow ustar headers

Jeff King [off-list ref] writes:

quoted

+#if ULONG_MAX == 0x7FFFFFFF
+#define USTAR_MAX_SIZE ULONG_MAX
+#define USTAR_MAX_MTIME ULONG_MAX
+#else
 #define USTAR_MAX_SIZE 077777777777UL
 #define USTAR_MAX_MTIME 077777777777UL
+#endif
 
 /* writes out the whole block, but only if it is full */
 static void write_if_needed(void)

If for some reason we are wrong that objects cannot be larger than
ULONG_MAX (e.g., later on we convert everything to size_t, and 64-bit
LLP platforms handle large objects just fine), then we would prematurely
switch to extended headers on those platforms.

I think that's OK. This would just need cleaned up as part of the
conversion from "unsigned long" to "size_t" (the correct check would
then be against the max size_t).

Also, shouldn't it be checking against 0xFFFFFFFF?

Correct.  Somehow I thought I was checking with LONG_MAX.  Will correct.

An easier check would be "sizeof()", but I guess we can't use that in a
preprocessor directive.

Yes, I tried it and failed ;-)

quoted

-test_expect_success TAR_HUGE 'system tar can read our huge size' '
+test_expect_success TAR_HUGE,64BIT 'system tar can read our huge size' '

The 64BIT prereq is really "unsigned long is 64-bit". I wonder if we
should call it UL64 or something like that to make it more clear.

That makes it unnecessarily tied-in with the implementation, but it does
make it more clear what we care about; the distinction matters for
things like LP64 vs LLP64.

I do not think any platform is weird enough to have different sizes
for long and ulong, so I am not sure you need UL64.

But pointer size can legitimately be different, so it has a value to
differentiate between LP64 and LLP64, if we start doing things like
"does this platform have large virtual address space?"

LONG_IS_64BIT perhaps to be more readable?