mintty --log overwrites existing logfile in place

mintty --log overwrites existing logfile in place

[Christian Franke]

The mintty --log option is very useful but opens logfile without O_TRUNC
or O_APPEND:

mintty-1.0.1/child.c:
  // Open log file if any
  if (*cfg.log) {
    log_fd = open(cfg.log, O_WRONLY | O_CREAT, 0600);
    if (log_fd < 0)
      error("open log file");
  } 

Then it is sometimes difficult to determine where the new log output
ends :-)
I would suggest to add O_APPEND.

Thanks,
Christian




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Re: mintty --log overwrites existing logfile in place

[Andy Koppe]

On 4 August 2011 10:57, Christian Franke wrote:
> The mintty --log option is very useful but opens logfile without O_TRUNC
> or O_APPEND:

D'oh!

> mintty-1.0.1/child.c:
>  // Open log file if any
>  if (*cfg.log) {
>    log_fd = open(cfg.log, O_WRONLY | O_CREAT, 0600);
>    if (log_fd < 0)
>      error("open log file");
>  }
>
> Then it is sometimes difficult to determine where the new log output
> ends :-)
>
> I would suggest to add O_APPEND.

I'll ponder that. The original intention was O_TRUNC.

Thanks,
Andy

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Re: mintty --log overwrites existing logfile in place

[Csaba Raduly]

On Fri, Aug 5, 2011 at 10:38 PM, Andy Koppe  wrote:
> On 4 August 2011 10:57, Christian Franke wrote:
>> The mintty --log option is very useful but opens logfile without O_TRUNC
>> or O_APPEND:
(snip)
>> I would suggest to add O_APPEND.
>
> I'll ponder that. The original intention was O_TRUNC.
>

Ideally it could be made user-selectable.
The effect of O_TRUNC can be manually replicated by deleting the
existing log, but I suspect few would bother; resulting in large log
files.
The effect of o_APPEND can be manually replicated by renaming and
concatenating the log files.

Csaba
-- 
GCS a+ e++ d- C++ ULS$ L+$ !E- W++ P+++$ w++$ tv+ b++ DI D++ 5++
The Tao of math: The numbers you can count are not the real numbers.
Life is complex, with real and imaginary parts.
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Re: mintty --log overwrites existing logfile in place

[Christian Franke]

Csaba Raduly wrote:
> On Fri, Aug 5, 2011 at 10:38 PM, Andy Koppe  wrote:
>    
>> On 4 August 2011 10:57, Christian Franke wrote:
>>      
>>> The mintty --log option is very useful but opens logfile without O_TRUNC
>>> or O_APPEND:
>>>        
> (snip)
>    
>>> I would suggest to add O_APPEND.
>>>        
>> I'll ponder that. The original intention was O_TRUNC.
>>
>>      
> Ideally it could be made user-selectable.
>    

Agree, e.g. "--log +FILE" appends to FILE:

client.c:
   // Open log file if any
   if (*cfg.log) {
     if (cfg.log[0] == '+' && cfg.log[1])
       log_fd = open(cfg.log+1, O_WRONLY | O_CREAT | O_APPEND, 0600);
     else
       log_fd = open(cfg.log, O_WRONLY | O_CREAT | O_TRUNC, 0600);
     if (log_fd < 0)
       error("open log file");
   }

Thanks,
Christian


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Re: mintty --log overwrites existing logfile in place

[Csaba Raduly]

On Sat, Aug 6, 2011 at 12:37 PM, Christian Franke  wrote:
> Agree, e.g. "--log +FILE" appends to FILE:
>
> client.c:
>  // Open log file if any
>  if (*cfg.log) {
>    if (cfg.log[0] == '+' && cfg.log[1])
>      log_fd = open(cfg.log+1, O_WRONLY | O_CREAT | O_APPEND, 0600);
>    else
>      log_fd = open(cfg.log, O_WRONLY | O_CREAT | O_TRUNC, 0600);
>    if (log_fd < 0)
>      error("open log file");
>  }

I was thinking along the lines of a user preference. I don't like
magic file names. But it's up to Andy :)

Csaba
-- 
GCS a+ e++ d- C++ ULS$ L+$ !E- W++ P+++$ w++$ tv+ b++ DI D++ 5++
The Tao of math: The numbers you can count are not the real numbers.
Life is complex, with real and imaginary parts.
"Ok, it boots. Which means it must be bug-free and perfect. " -- Linus Torvalds
"People disagree with me. I just ignore them." -- Linus Torvalds

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