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Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write()
From: |
Chen Gang |
Subject: |
Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file() |
Date: |
Sat, 21 Jun 2014 10:25:31 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 |
On 06/21/2014 05:53 AM, Chet Ramey wrote:
> On 6/20/14, 4:57 AM, Chen Gang wrote:
>> On 06/19/2014 09:31 AM, Chen Gang wrote:
>>>
>>>
>>> On 06/19/2014 04:33 AM, Chet Ramey wrote:
>>>> On 6/10/14, 10:35 PM, Chen Gang wrote:
>>>>> For regular file, write() operation may also fail, so check it too. If
>>>>> write() return 0, can simply wait and try again, it should not suspend
>>>>> infinitely if environments have no critical issues.
>>>>
>>>> Readline-6.3 checks the return value from write() and returns a non-zero
>>>> value to the history_truncate_file caller. I really don't think that
>>>> waiting forever if write continues to return 0 is a great idea; an error
>>>> return is enough to let the caller deal with it.
>>>>
>>
>> Oh, sorry, after think of again, for me, we have to waiting forever if
>> write() continues to return 0.
>
> There aren't really any plausible conditions under which write(2) returns
> 0 instead of -1 when writing a non-zero number of bytes to a regular file.
>
Hmm... for me, what you said is acceptable. And the function comment need be
changed:
"Returns 0 on success, errno or -1 on failure"
>>
>> When this case happens, the file is already truncated, and the left data
>> which is writing to file will be free after return from
>> history_truncate_file().
>>
>> If return an error code in this case, the caller can not deal with it --
>> the log data which should be remained, have been lost, can not get them
>> back again.
>
> However, you're right about the data being lost if write fails and returns
> -1. Since the sequence of operations is open-read-close-open-write-close, I
> think I will change the code for the next version to use a scheme similar
> to history_do_write() and restore the original version of the file if the
> write fails.
>
OK, thanks.
And since you will work for it next, is it still necessary to send patch v2 for
the temporary fix, at present?
Thanks
--
Open share and attitude like air warter and life which God blessed
- [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(), Chen Gang, 2014/06/11
- Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(), Chet Ramey, 2014/06/18
- Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(), Chen Gang, 2014/06/18
- Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(), Chen Gang, 2014/06/20
- Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(), Chet Ramey, 2014/06/20
- Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(),
Chen Gang <=
- Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(), Chet Ramey, 2014/06/21
- Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(), Chen Gang, 2014/06/21
- Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(), Chet Ramey, 2014/06/23
- Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(), Chen Gang, 2014/06/23
- Re: [Bug-readline] [PATCH] readline/histfile.c: Check and retry write() operation in history_truncate_file(), Chen Gang, 2014/06/25