On 20 May 2016 at 19:13, Hao Lee <mixt...@gmail.com> wrote: > > Hi all, > > Today, I am do some works on adding some customized featues to PostgreSQL 9.6 > beta1. But, when i do some output to psql using the fuction > "do_text_output_multiline" with the string just like mentioned in mail tilte, > such as "this is a\ntest for\nnew blank.". the PostgreSQL may lead to > corruption in this function, and i debugged it that found this function can > not dealt with the boundaries properly. The original function code as : > > do_text_output_multiline(TupOutputState *tstate, char *text) > { > Datum values[1]; > bool isnull[1] = {false}; > > while (*text) > { > char *eol; > int len; > > eol = strchr(text, '\n'); > if (eol) > { > len = eol - text; > > eol++; > } > else > { > len = strlen(text); > eol += len; > } > > values[0] = PointerGetDatum(cstring_to_text_with_len(text, len)); > do_tup_output(tstate, values, isnull); > pfree(DatumGetPointer(values[0])); > text = eol; > } > } >
Thanks for reporting this. It does seem pretty broken. I guess we've only gotten away with this due to EXPLAIN output lines always having a \n at the end of them, but we should fix this. Your proposed fix looks a little bit confused. You could have just removed the eol += len; as testing if (eol) in the else will never be true as that else is only being hit because eol is NULL. I shuffled things around in there a bit and came up with the attached fix. -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
do_text_output_multiline_fix.patch
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