Bug 266224

Summary:	Could some sort of file transfer program be put in /rescue?
Product:	Base System	Reporter:	Dan Mahoney <freebsd>
Component:	bin	Assignee:	Xin LI <delphij>
Status:	Closed FIXED
Severity:	Affects Only Me	CC:	delphij, emaste, grahamperrin, john.grafton
Priority:	---	Keywords:	feature
Version:	12.2-RELEASE
Hardware:	Any
OS:	Any
See Also:	https://reviews.freebsd.org/D38193 https://reviews.freebsd.org/D38304

Description Dan Mahoney 2022-09-04 19:52:25 UTC

Hey there,

I run a network of DNS servers, out there in cold unforgiving data centers in places in the world where remote hands are hard to come by and the only connectivity you get sometimes is a serial console.  Often you'll get clueful techs who will reboot a machine for you but not much more.

Numerous times, I've been bitten by freebsd-update segfaulting and leaving me with an unusable system that won't survive a reboot (either because of a failure to replace ld.so or because of a full /var or / or other partition).

At that point you're logged in to a system over ssh, you cannot ssh in a second time, and you need to recover the system quickly.

The only real fix is to copy binaries (or a base.txz) from another machine using the statically linked binaries in /rescue.  And other than nc (which works, but has no progress indicator and no real checks), there's no easy way to get files onto and off a system.

I get it, scp and ssh have heavy crypto overhead, as does fetch at this point, but a fetch-lite that only spoke HTTP and FTP would be super useful, as would a copy of old school ftp.  Or, you know, maybe just a statically linked scp/ssh *is* the right answer here.  (Busybox is a cool idea but it has the GPL issue).

There's no patch for this, it's more an enhancement request.

Comment 1 John Grafton 2023-01-24 19:05:15 UTC

I think a limited version of fetch in /rescue is a good idea!  I'll take a go at building one.

For stream progress during transfers in rescue mode, I use `dd status=progress`.  It's not something I've had to do very often since the systems I manage I can lay hands on but it works in a pinch.

sending:
# cat base.txz | nc broken-host.example.net 9999

receiving:
# /rescue/nc -l 9999 | /rescue/dd status=progress > /base.txz

Then I use /rescue/md5 to verify the tarball.  :)

Comment 2 John Grafton 2023-01-25 15:58:00 UTC

Review for adding fetch to /rescue:  https://reviews.freebsd.org/D38193

Comment 3 commit-hook freebsd_committer

2023-01-29 23:06:34 UTC

A commit in branch main references this bug:

URL: https://cgit.FreeBSD.org/src/commit/?id=ea34aa4780e5a581732520ea579342af94684882

commit ea34aa4780e5a581732520ea579342af94684882
Author:     John Grafton <john.grafton@runbox.com>
AuthorDate: 2023-01-29 23:05:15 +0000
Commit:     Xin LI <delphij@FreeBSD.org>
CommitDate: 2023-01-29 23:05:15 +0000

    rescue: Add fetch(1) to the rescue tool.

    After a failed upgrade, having fetch(1) on a system that is
    physically unnreachable would be very useful to download files
    required to get the OS back up and functional.

    On my system this adds 589,824 bytes (3.8%) to the binary size.

    PR:             266224
    Reported by:    Dan Mahoney
    MFC after:      2 weeks
    Differential Revision:  https://reviews.freebsd.org/D38193

 rescue/rescue/Makefile | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comment 4 commit-hook freebsd_committer

2023-02-12 07:56:35 UTC

A commit in branch stable/13 references this bug:

URL: https://cgit.FreeBSD.org/src/commit/?id=03abf6cd13bdd97c865f5731688cf72931078729

commit 03abf6cd13bdd97c865f5731688cf72931078729
Author:     John Grafton <john.grafton@runbox.com>
AuthorDate: 2023-01-29 23:05:15 +0000
Commit:     Xin LI <delphij@FreeBSD.org>
CommitDate: 2023-02-12 07:55:02 +0000

    rescue: Add fetch(1) to the rescue tool.

    After a failed upgrade, having fetch(1) on a system that is
    physically unnreachable would be very useful to download files
    required to get the OS back up and functional.

    On my system this adds 589,824 bytes (3.8%) to the binary size.

    PR:             266224
    Reported by:    Dan Mahoney
    Differential Revision:  https://reviews.freebsd.org/D38193

    (cherry picked from commit ea34aa4780e5a581732520ea579342af94684882)

    rescue: Fix link order of SSL libraries and fetch.

    ld.bfd requires libraries to be linked in order.  libssl requires
    libcrypto.  libfetch requires libssl.  To fix the latter, move fetch
    up above tar rather than listing the ssl libraries twice.

    Reviewed by:    delphij
    Fixes:          ea34aa4780e5 rescue: Add fetch(1) to the rescue tool.
    Differential Revision:  https://reviews.freebsd.org/D38304

    (cherry picked from commit 0f031350f32b8760e0843a6476d67aa21116103b)

 rescue/rescue/Makefile | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Comment 5 commit-hook freebsd_committer

2023-02-12 07:59:37 UTC

A commit in branch stable/12 references this bug:

URL: https://cgit.FreeBSD.org/src/commit/?id=ffb598d0953a328b30744ac56e8f1fd0344fd733

commit ffb598d0953a328b30744ac56e8f1fd0344fd733
Author:     John Grafton <john.grafton@runbox.com>
AuthorDate: 2023-01-29 23:05:15 +0000
Commit:     Xin LI <delphij@FreeBSD.org>
CommitDate: 2023-02-12 07:58:55 +0000

    rescue: Add fetch(1) to the rescue tool.

    After a failed upgrade, having fetch(1) on a system that is
    physically unnreachable would be very useful to download files
    required to get the OS back up and functional.

    On my system this adds 589,824 bytes (3.8%) to the binary size.

    PR:             266224
    Reported by:    Dan Mahoney
    Differential Revision:  https://reviews.freebsd.org/D38193

    (cherry picked from commit ea34aa4780e5a581732520ea579342af94684882)

    rescue: Fix link order of SSL libraries and fetch.

    ld.bfd requires libraries to be linked in order.  libssl requires
    libcrypto.  libfetch requires libssl.  To fix the latter, move fetch
    up above tar rather than listing the ssl libraries twice.

    Reviewed by:    delphij
    Fixes:          ea34aa4780e5 rescue: Add fetch(1) to the rescue tool.
    Differential Revision:  https://reviews.freebsd.org/D38304

    (cherry picked from commit 0f031350f32b8760e0843a6476d67aa21116103b)

 rescue/rescue/Makefile | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)