Re: [pacman-dev] [PATCH v2] Do not continuously try to open an invalid database

[Mar77i via pacman-dev]

> Original Message 
>Subject: Re: [pacman-dev] [PATCH v2] Do not continuously try to open an 
>invalid database
>Local Time: January 9, 2018 2:58 PM
>UTC Time: January 9, 2018 1:58 PM
>From: d...@falconindy.com
>To: Discussion list for pacman development 
>
>On Tue, Jan 09, 2018 at 10:07:13PM +1000, Allan McRae wrote:
>>If you manage to download a bad database (e.g. an html file when
>> behind a proxy or with a badly configured webserver), pacman makes
>> sure you know about it.  Here is some example output:
>>error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>>archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
>> archive format
>>I don't know how many times that gets printed because it goes beyond my 
>>scrollback
>> buffer.
>>Flag a database that we can "open" and "fstat" but not read from as invalid 
>>to avoid
>> this.
>>Signed-off-by: Allan McRae al...@archlinux.org
>>
>>Review of v1:
>>https://lists.archlinux.org/pipermail/pacman-dev/2017-May/022027.html
>>v2 - do much less stuff to achive the same result...
>>lib/libalpm/be_sync.c | 1 +
>> 1 file changed, 1 insertion(+)
>>diff --git a/lib/libalpm/be_sync.c b/lib/libalpm/be_sync.c
>> index 1b7c8b6f..389e964c 100644
>> --- a/lib/libalpm/be_sync.c
>> +++ b/lib/libalpm/be_sync.c
>> @@ -486,6 +486,7 @@ static int sync_db_populate(alpm_db_t *db)
>> fd = _alpm_open_archive(db->handle, dbpath, ,
>> , ALPM_ERR_DB_OPEN);
>> if(fd < 0) {
>> - db->status &= DB_STATUS_INVALID;
>>
>>
> Given that DB_STATUS_INVALID is a single bit, shouldn't this be a simple
> assignment? A bitwise 'and' here will result in the status remaining
> invalid if it's already invalid, or zero'ing it out (DB_STATUS_VALID) if
> it's some other set of bits. That doesn't seem like what we want.
>


He's right. &= SOMETHING seems odd. There are three usual operations for single 
bit assignments: &= ~SOMETHING, |= SOMETHING and ^= SOMETHING.

cheers!
mar77i

​
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Re: [pacman-dev] [PATCH v2] Do not continuously try to open an invalid database

[Dave Reisner]

On Tue, Jan 09, 2018 at 10:07:13PM +1000, Allan McRae wrote:
> If you manage to download a bad database (e.g. an html file when
> behind a proxy or with a badly configured webserver), pacman makes
> sure you know about it.  Here is some example output:
> 
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> error: could not open file /var/lib/pacman/sync/extra.db: Unrecognized 
> archive format
> 
> I don't know how many times that gets printed because it goes beyond my 
> scrollback
> buffer.
> 
> Flag a database that we can "open" and "fstat" but not read from as invalid 
> to avoid
> this.
> 
> Signed-off-by: Allan McRae 
> ---
> 
> Review of v1:
> https://lists.archlinux.org/pipermail/pacman-dev/2017-May/022027.html
> 
> v2 - do much less stuff to achive the same result...
> 
> 
>  lib/libalpm/be_sync.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/lib/libalpm/be_sync.c b/lib/libalpm/be_sync.c
> index 1b7c8b6f..389e964c 100644
> --- a/lib/libalpm/be_sync.c
> +++ b/lib/libalpm/be_sync.c
> @@ -486,6 +486,7 @@ static int sync_db_populate(alpm_db_t *db)
>   fd = _alpm_open_archive(db->handle, dbpath, ,
>   , ALPM_ERR_DB_OPEN);
>   if(fd < 0) {
> + db->status &= DB_STATUS_INVALID;

Given that DB_STATUS_INVALID is a single bit, shouldn't this be a simple
assignment? A bitwise 'and' here will result in the status remaining
invalid if it's already invalid, or zero'ing it out (DB_STATUS_VALID) if
it's some other set of bits. That doesn't seem like what we want.

Semi-related thought: it's a bit odd that we semantically chose "0" as
valid, and "1" as invalid.

>   return -1;
>   }
>   est_count = estimate_package_count(, archive);
> -- 
> 2.15.1