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

[Andrew Gregory]

On 05/09/17 at 11:38am, 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 <allan at archlinux.org>
> ---
>  lib/libalpm/be_sync.c | 3 +++
>  lib/libalpm/util.c    | 1 +
>  2 files changed, 4 insertions(+)
> 
> diff --git a/lib/libalpm/be_sync.c b/lib/libalpm/be_sync.c
> index 06f509a6..46959298 100644
> --- a/lib/libalpm/be_sync.c
> +++ b/lib/libalpm/be_sync.c
> @@ -486,6 +486,9 @@ static int sync_db_populate(alpm_db_t *db)
>  	fd = _alpm_open_archive(db->handle, dbpath, &buf,
>  			&archive, ALPM_ERR_DB_OPEN);
>  	if(fd < 0) {
> +		if(db->handle->pm_errno == ALPM_ERR_DB_INVALID) {
> +			db->status &= DB_STATUS_INVALID;
> +		}

ACK

>  		return -1;
>  	}
>  	est_count = estimate_package_count(&buf, archive);
> diff --git a/lib/libalpm/util.c b/lib/libalpm/util.c
> index 35fc7f41..0fb9bb6d 100644
> --- a/lib/libalpm/util.c
> +++ b/lib/libalpm/util.c
> @@ -268,6 +268,7 @@ int _alpm_open_archive(alpm_handle_t *handle, const char *path,
>  	if(archive_read_open_fd(*archive, fd, bufsize) != ARCHIVE_OK) {
>  		_alpm_log(handle, ALPM_LOG_ERROR, _("could not open file %s: %s\n"),
>  				path, archive_error_string(*archive));
> +		error = ALPM_ERR_DB_INVALID;

We shouldn't be using a db-specific error here.  _alpm_open_archive is
used for packages as well.  If we want to differentiate between open
and format failures we'll either have to take a second error code or
set return values and let the caller set the handle error based on
that.  I think the ALPM_ERR_*_OPEN codes we're using for this function
now are fine, though.

>  		goto error;
>  	}
>  
> -- 
> 2.12.2