On 09/28/2012 12:48 AM, Junio C Hamano wrote:
> Michael Haggerty <mhag...@alum.mit.edu> writes:
>> -    for (colon = ceil = prefix_list; *colon; ceil = colon+1) {
>> -            for (colon = ceil; *colon && *colon != PATH_SEP; colon++);
>> -            len = colon - ceil;
>> +    string_list_split(&prefixes, prefix_list, PATH_SEP, -1);
>> +
>> +    for (i = 0; i < prefixes.nr; i++) {
>> +            const char *ceil = prefixes.items[i].string;
>> +            int len = strlen(ceil);
>> +
> Much nicer than the yucky original ;-)

If your winky-smiley implies irony, then I would like to object.  Even
though the original is not difficult to understand, it is more difficult
to review than the new version because one has to think about off-by-one
errors etc.  The new version has a bit more boilerplate, but a quick
read suffices both to understand it and to see that it is correct.
Though of course I admit that the improvement is small.

But the main point of this change is to move towards using more testable
parts, so it is a step forward regardless of whether it is more readable.

>>              if (len == 0 || len > PATH_MAX || !is_absolute_path(ceil))
>>                      continue;
>> -            strlcpy(buf, ceil, len+1);
>> +            memcpy(buf, ceil, len+1);
>>              if (normalize_path_copy(buf, buf) < 0)
>>                      continue;
> Why do you need this memcpy in the first place?  Isn't ceil already
> a NUL terminated string unlike the original code that points into a
> part of the prefix_list string?  IOW, why not
>       normalize_path_copy(buf, ceil);
> or something?

Good point.  I will fix this in v2.

> Can normalize_path_copy() overflow buf[PATH_MAX+1] here (before or
> after this patch)?

normalize_path_copy() can only shrink paths, not grow them.  So the
length check on ceil guarantees that the result of normalize_path_copy()
will fit in buf.


Michael Haggerty
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