df073671e8
to hide meta-characters in the result when the expansion was in (double) quotes, and so should not be further processed. Most of this has been OK for a long while, but \ needs hiding as well, which complicates things, as \ cannot simply be hidden in the syntax tables as one of the group of random special characters. This was fixed earlier for simple variable expansions, but every variety has its own code path ($var uses different code than $n which is different than $(...), which is different again from ~ expansions, and also from what $'...' produces). This could be fixed by moving them all to a common code path, but that's harder than it seems. The form in which the data is made available differs, so one common routine would need a whole bunch of different "get the next char or indicate end" methods - probably via passing in an accessor function. That's all a lot of churn, and would probably slow the shell. Instead, just make macros for doing the standard tests, and use those instead of open coding (differently) each time. This way some of the code paths don't end up forgetting to handle '\' (which is different than all the others). This removes one optimisation ... when no escaping is needed (like just $var (unquoted) where magic chars (think '*') in the value are intended to remain magic), the code avoided doing two tests for each char ("do we need escapes" and "is this char one that needs escaping") by choosing two different syntax tables (choice made outside the loop) - one of which never returns the magic "needs escaping" result, and the other does when appropriate, and then just avoiding the "do we need escapes" test for each character processed. Then when '\' was fixed, there needed to be another test for it, as it cannot (for other reasons) be the same as all the others for which "this char need escaping" is true. So that added a 2nd test for each char... Not all the code paths were updated. Hence the bugs... nb: this is all rarely seen in the wild, so it is no big surprised that no-one ever noticed. Now the "use two different syntax tables" is gone (the two returned the same for '\' which is why '\' needed special processing) - and in order to avoid two tests for each char (plus the \ test) we duplicate the loops, one of which tests each char to see if it needs an escape, the 2nd just copies them. This should be faster in the "no escapes" code path (though that is not the point) and perhaps also in the "escapes needed" path (no indirect reference to the syntax table - though that would probably be in a register) but makes the code slightly bigger. For /bin/sh the text segment (on amd64) has grown by 48 bytes. But it still uses the same number of 512 byte pages (and hence also any bigger page size). The resulting file size (/bin/sh) is identical before and after. So is /rescue/sh (or /rescue/anything-else). |
||
---|---|---|
.. | ||
cat | ||
chio | ||
chmod | ||
cp | ||
csh | ||
date | ||
dd | ||
df | ||
domainname | ||
echo | ||
ed | ||
expr | ||
hostname | ||
kill | ||
ksh | ||
ln | ||
ls | ||
mkdir | ||
mt | ||
mv | ||
pax | ||
ps | ||
pwd | ||
rcmd | ||
rcp | ||
rm | ||
rmdir | ||
sh | ||
sleep | ||
stty | ||
sync | ||
test | ||
Makefile | ||
Makefile.inc |