On 11/26/19 4:29 PM, Ethan Sommer wrote: > Previously, to determine which command we should use to extract an > archive, we would run file and match the output against our list of > possible extraction commands > > Instead, run the archive through each extraction command's -t (--test) > flag, if this succeeds then we know that the command is able to extract > the file and is the one to use
Missing rationale why we care.
> scripts/libmakepkg/source/file.sh.in | 39 ++++++++--------------------
> 1 file changed, 11 insertions(+), 28 deletions(-)
>
> diff --git a/scripts/libmakepkg/source/file.sh.in
> b/scripts/libmakepkg/source/file.sh.in
> index 7297a1c6..faace79b 100644
> --- a/scripts/libmakepkg/source/file.sh.in
> +++ b/scripts/libmakepkg/source/file.sh.in
> @@ -96,35 +96,18 @@ extract_file() {
> fi
>
> # do not rely on extension for file type
> - local file_type=$(@FILECMD@ -bizL -- "$file")
> - local ext=${file##*.}
> local cmd=''
> - case "$file_type" in
> -
> *application/x-tar*|*application/zip*|*application/x-zip*|*application/x-cpio*)
> - cmd="bsdtar" ;;
> - *application/x-gzip*|*application/gzip*)
> - case "$ext" in
> - gz|z|Z) cmd="gzip" ;;
> - *) return;;
> - esac ;;
> - *application/x-bzip*)
> - case "$ext" in
> - bz2|bz) cmd="bzip2" ;;
> - *) return;;
> - esac ;;
> - *application/x-xz*)
> - case "$ext" in
> - xz) cmd="xz" ;;
> - *) return;;
> - esac ;;
> - *)
> - # See if bsdtar can recognize the file
> - if bsdtar -tf "$file" -q '*' &>/dev/null; then
> - cmd="bsdtar"
> - else
> - return 0
> - fi ;;
> - esac
> + if bsdtar -tf "$file" -q '*'; then
> + cmd='bsdtar'
> + elif gzip -t "$file"; then
> + cmd='gzip'
> + elif bzip2 -t "$file"; then
> + cmd='bzip2'
> + elif xz -t "$file"; then
> + cmd='xz'
> + else
> + return 0
> + fi &>/dev/null
I had to look at this three times before I realized you were redirecting
both stdout and stderr of the entire if/elif block.
Because these commands check to see if the file is "uncorrupted", not to
see if they are "formatted in this compression format", I imagine this
would falsely fail files if they have some class of recoverable error,
but I'm not sure if we care.
What we do care about, I think, is that you're silencing stderr due to
the fact that it will noisily print diagnostic messages when the file is
not compressed or is in a different compression format, and bsdtar will
print listed filenames to stdout. So now, if these commands fail for
*any* reason, we treat this as a successful analysis that the file is in
a different format. One reason for it failing might be that xz is not
installed... this is hardly a successful analysis, and printing an
"error: command not found" message during the decompression, then dying
with "Failed to extract %s" is a desirable feature.
> local ret=0
> msg2 "$(gettext "Extracting %s with %s")" "$file" "$cmd"
>
--
Eli Schwartz
Bug Wrangler and Trusted User
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