From: Stefan Beller <sbeller@google.com>
Date: Wed, 30 Mar 2016 16:41:38 GMT
Subject: Re: [PATCH 1/6] path.c: allocate enough memory for string
Message-ID: <CAGZ79kb6dsaSxQ+HaYODBurnFz3MbsisSNkdrckFZLvSCvS-JQ@mail.gmail.com>
In-Reply-To: <CAPig+cSqC1muy+vcmpkp9uM9T3CC4pa5jWGUot_FtrVshEAUEw@mail.gmail.com>

On Tue, Mar 29, 2016 at 5:57 PM, Eric Sunshine <sunshine@sunshineco.com> wrote:
> On Tue, Mar 29, 2016 at 8:38 PM, Stefan Beller <sbeller@google.com> wrote:
>> `strlen` returns the length of a string without the terminating null byte.
>> To make sure enough memory is allocated we need to pass `strlen(..) + 1`
>> to the allocation function.
>>
>> Signed-off-by: Stefan Beller <sbeller@google.com>
>> ---
>> diff --git a/path.c b/path.c
>> @@ -155,7 +155,7 @@ static struct trie *make_trie_node(const char *key, void *value)
>>         struct trie *new_node = xcalloc(1, sizeof(*new_node));
>>         new_node->len = strlen(key);
>>         if (new_node->len) {
>> -               new_node->contents = xmalloc(new_node->len);
>> +               new_node->contents = xmalloc(new_node->len + 1);
>>                 memcpy(new_node->contents, key, new_node->len);
>
> Huh? This is a trie. It never accesses 'contents' as a NUL-terminated
> string. Plus, no NUL is ever even copied, thus this is just
> overallocating. How is this an improvement?

By using strlen, I assumed it was a standard C string.
I missed that, though.

>
>>         }
>>         new_node->value = value;
>> --