[FFmpeg-devel] [PATCH] Adding support for OSX bundles to ffmpeg command line

[Chris Marrin]

On Mar 20, 2009, at 3:25 PM, M?ns Rullg?rd wrote:

> Chris Marrin <chris at marrin.com> writes:
>
>> On Mar 20, 2009, at 2:37 PM, M?ns Rullg?rd wrote:
>>
>>> Chris Marrin <chris at marrin.com> writes:
>>>
>>>> On Mar 20, 2009, at 9:50 AM, M?ns Rullg?rd wrote:
>>>>
>>>>> Chris Marrin <chris at marrin.com> writes:
>>>>>
>>>>>> @@ -3915,7 +3930,16 @@
>>>>>> {
>>>>>>   int i;
>>>>>>   int64_t ti;
>>>>>> -
>>>>>> +
>>>>>> +    // get the executable path
>>>>>> +    char* p = strrchr(argv[0], '/');
>>>>>> +    if (p) {
>>>>>> +        int length = p-argv[0];
>>>>>> +        executable_path = av_malloc(length+1);
>>>>>> +        strncpy(executable_path, argv[0], length);
>>>>>> +        executable_path[length] = '\0';
>>>>>> +    }
>>>>>> +
>>>>>
>>>>> There are a million ways in which this can fail.
>>>>
>>>> I can find a few:
>>>>
>>>> 1) executable_path is not set to null if the if test fails (along
>>>> with
>>>> the corresponding check for null where used).
>>>> 2) The malloc can fail.
>>>> 3) In the unimaginably unlikely case that argv[0] contained a  
>>>> string
>>>> of greater than 2GB with a slash at the end, the length would wrap
>>>> 4) The executable_path is leaked (not a failure, but I can fix it)
>>>>
>>>> I can fix all those. Others?
>>>
>>> 5) argv[0] doesn't contain the (expected) path to the executable.
>>> There are a number of ways this can realistically happen.
>>
>> The outcome of which is that a) the string looks nothing like a path
>> and executable_path is empty or b) the string looks something like a
>> path and executable_path contains nonsense. In either case you would
>> not find the preset and fallback to existing behavior. I suppose
>> argv[0] could even be null, so a check for that is needed?
>>
>> Any more dangers?
>
> It could point to a location containing presets, but the wrong ones.
> It could use something other than / as directory separator.
>
> Using argv[0] is generally wrong, period.


Any suggestions on a better way to get the executable path (that are  
not platform specific)? Does ffmpeg have a function to get it?

-----
~Chris
chris at marrin.com