Re: [PATCH 3/3] builtin/help.c: fix memory leak

From: Stefan Beller <sbeller@google.com>
Date: Mar 10, 2015, 23:50 UTC
Message-ID: <CAGZ79kYSBsfbR_gH1Ur12vMpcK5S0K6wrOpMhNVvgffAb683Bw@mail.gmail.com>
In-Reply-To: <xmqqwq2oxyli.fsf@gitster.dls.corp.google.com>

On Tue, Mar 10, 2015 at 3:43 PM, Junio C Hamano <gitster@pobox.com> wrote:

Show 28 quoted lines

> Stefan Beller <sbeller@google.com> writes:
>
>> Signed-off-by: Stefan Beller <sbeller@google.com>
>> ---
>>  builtin/help.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/builtin/help.c b/builtin/help.c
>> index 6133fe4..a1f5a0a 100644
>> --- a/builtin/help.c
>> +++ b/builtin/help.c
>> @@ -456,7 +456,7 @@ static void list_common_guides_help(void)
>>  int cmd_help(int argc, const char **argv, const char *prefix)
>>  {
>>       int nongit;
>> -     const char *alias;
>> +     char *alias;
>>       enum help_format parsed_help_format;
>>
>>       argc = parse_options(argc, argv, prefix, builtin_help_options,
>> @@ -499,6 +499,7 @@ int cmd_help(int argc, const char **argv, const char *prefix)
>>       alias = alias_lookup(argv[0]);
>>       if (alias && !is_git_command(argv[0])) {
>>               printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
>> +             free(alias);
>
> Hmph, does this memory belong to us, or are we peeking into the
> cached data in the config cache layer?

So alias_lookup(..) is a wrapper around git_config_string essentially (some more git_config_functions are involved, but we eventually reach git_config_string), where we have

    *dest = xstrdup(value);

so I think we need to free that memory, as the config cache layer doesn't care any more.