Re: Review: psql include file using relative path - Mailing list pgsql-hackers

On Fri, May 20, 2011 at 2:35 PM, Gurjeet Singh <singh.gurjeet@gmail.com> wrote:
> On Sat, May 14, 2011 at 5:03 PM, Josh Kupershmidt <schmiddy@gmail.com>
> wrote:
> Thanks a lot for the review. My responses are inline below.

Thanks for the fixes. Your updated patch is sent as a
patch-upon-a-patch, it'll probably be easier for everyone
(particularly the final committer) if you send inclusive patches
instead.

>> == Documentation ==
>> The patch includes the standard psql help output description for the
>> new \ir command. I think ./doc/src/sgml/ref/psql-ref.sgml needs to be
>> patched as well, though.
>
> Done.

This is a decent description from a technical standpoint:
       <para>       When used within a script, if the <replaceable
class="parameter">filename</replaceable>       uses relative path notation, then the file will be looked up
relative to currently       executing file's location.
       If the <replaceable class="parameter">filename</replaceable>
uses an absolute path       notation, or if this command is being used in interactive
mode, then it behaves the       same as <literal>\i</> command.       </para>

but I think these paragraphs could be made a little more clear, by
making a suggestion about why someone would be interested in \ir. How
about this:
       <para>       The <literal>\ir</> command is similar to <literal>\i</>, but
is useful for files which       load in other files.
       When used within a file loaded via <literal>\i</literal>,
<literal>\ir</literal>, or       <option>-f</option>, if the <replaceable
class="parameter">filename</replaceable>       is specified with a relative path, then the location of the
file will be determined       relative to the currently executing file's location.       </para>
       <para>       If <replaceable class="parameter">filename</replaceable> is given as an       absolute path, or if
thiscommand is used in interactive mode, then       <literal>\ir</> behaves the same as the <literal>\i</> command.
 </para>
 

The sentence "When used within a file ..." is now a little
clunky/verbose, but I was trying to avoid potential confusion from
someone trying \ir via 'cat ../filename.sql | psql', which would be
"used within a script", but \ir wouldn't know that.


>> == Code ==
>> 1.) I have some doubts about whether the memory allocated here:
>>    char *relative_file = pg_malloc(dir_len + 1 + file_len + 1);
>> is always free()'d, particularly if this condition is hit:
>>
>>    if (!fd)
>>    {
>>        psql_error("%s: %s\n", filename, strerror(errno));
>>        return EXIT_FAILURE;
>>    }
>
> Fixed.

Well, this fix:
    if (!fd)    {
+        if (relative_path != NULL)
+            free(relative_path);
+        psql_error("%s: %s\n", filename, strerror(errno));

uses the wrong variable name (relative_path instead of relative_file),
and the subsequent psql_error() call will then reference freed memory,
since relative_file was assigned to filename.

But even after fixing this snippet to get it to compile, like so:
   if (!fd)   {       psql_error("%s: %s\n", filename, strerror(errno));       if (relative_file != NULL)
free(relative_file);
       return EXIT_FAILURE;   }

I was still seeing memory leaks in valgrind growing with the number of
\ir calls between files (see valgrind_bad_report.txt attached). I
think that relative_file needs to be freed even in the non-error case,
like so:

error:   if (fd != stdin)       fclose(fd);
   if (relative_file != NULL)       free(relative_file);
   pset.inputfile = oldfilename;   return result;

At least, that fix seemed to get rid of the ballooning valgrind
reports for me. I then see a constant-sized < 500 byte leak complaint
from valgrind, the same as with unpatched psql.

>> 4.) I think the changes to process_file() merit another comment or
>> two, e.g. describing what relative_file is supposed to be.

> Added.

Some cleanup for this comment:

+        /*
+         * If the currently processing file uses \ir command, and the parameter
+         * to the command is a relative file path, then we resolve this path
+         * relative to currently processing file.

suggested tweak:
   If the currently processing file uses the \ir command, and the filename   parameter is given as a relative path,
thenwe resolve this path relative   to the currently processing file (pset.inputfile).
 

+         *
+         * If the \ir command was executed in interactive mode (i.e. not in a
+         * script) the we treat it the same as \i command.
+         */

suggested tweak:
   If the \ir command was executed in interactive mode (i.e. not in a   script, and pset.inputfile will be NULL) then
wetreat the filename   the same as the \i command does.
 

[snip]
The rest looks good.

Josh