Most of the callers of packet_read_line just read into a
static 1000-byte buffer (callers which handle arbitrary
binary data already use LARGE_PACKET_MAX). This works fine
in practice, because:
1. The only variable-sized data in these lines is a ref
name, and refs tend to be a lot shorter than 1000
characters.
2. When sending ref lines, git-core always limits itself
to 1000 byte packets.
However, the only limit given in the protocol specification
in Documentation/technical/protocol-common.txt is
LARGE_PACKET_MAX; the 1000 byte limit is mentioned only in
pack-protocol.txt, and then only describing what we write,
not as a specific limit for readers.
This patch lets us bump the 1000-byte limit to
LARGE_PACKET_MAX. Even though git-core will never write a
packet where this makes a difference, there are two good
reasons to do this:
1. Other git implementations may have followed
protocol-common.txt and used a larger maximum size. We
don't bump into it in practice because it would involve
very long ref names.
2. We may want to increase the 1000-byte limit one day.
Since packets are transferred before any capabilities,
it's difficult to do this in a backwards-compatible
way. But if we bump the size of buffer the readers can
handle, eventually older versions of git will be
obsolete enough that we can justify bumping the
writers, as well. We don't have plans to do this
anytime soon, but there is no reason not to start the
clock ticking now.
Just bumping all of the reading bufs to LARGE_PACKET_MAX
would waste memory. Instead, since most readers just read
into a temporary buffer anyway, let's provide a single
static buffer that all callers can use. We can further wrap
this detail away by having the packet_read_line wrapper just
use the buffer transparently and return a pointer to the
static storage. That covers most of the cases, and the
remaining ones already read into their own LARGE_PACKET_MAX
buffers.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The packets sent during ref negotiation are all terminated
by newline; even though the code to chomp these newlines is
short, we end up doing it in a lot of places.
This patch teaches packet_read_line to auto-chomp the
trailing newline; this lets us get rid of a lot of inline
chomping code.
As a result, some call-sites which are not reading
line-oriented data (e.g., when reading chunks of packfiles
alongside sideband) transition away from packet_read_line to
the generic packet_read interface. This patch converts all
of the existing callsites.
Since the function signature of packet_read_line does not
change (but its behavior does), there is a possibility of
new callsites being introduced in later commits, silently
introducing an incompatibility. However, since a later
patch in this series will change the signature, such a
commit would have to be merged directly into this commit,
not to the tip of the series; we can therefore ignore the
issue.
This is an internal cleanup and should produce no change of
behavior in the normal case. However, there is one corner
case to note. Callers of packet_read_line have never been
able to tell the difference between a flush packet ("0000")
and an empty packet ("0004"), as both cause packet_read_line
to return a length of 0. Readers treat them identically,
even though Documentation/technical/protocol-common.txt says
we must not; it also says that implementations should not
send an empty pkt-line.
By stripping out the newline before the result gets to the
caller, we will now treat the newline-only packet ("0005\n")
the same as an empty packet, which in turn gets treated like
a flush packet. In practice this doesn't matter, as neither
empty nor newline-only packets are part of git's protocols
(at least not for the line-oriented bits, and readers who
are not expecting line-oriented packets will be calling
packet_read directly, anyway). But even if we do decide to
care about the distinction later, it is orthogonal to this
patch. The right place to tighten would be to stop treating
empty packets as flush packets, and this change does not
make doing so any harder.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The current parsing scheme for upload-archive is to pack
arguments into a fixed-size buffer, separated by NULs, and
put a pointer to each argument in the buffer into a
fixed-size argv array.
This works fine, and the limits are high enough that nobody
reasonable is going to hit them, but it makes the code hard
to follow. Instead, let's just stuff the arguments into an
argv_array, which is much simpler. That lifts the "all
arguments must fit inside 4K together" limit.
We could also trivially lift the MAX_ARGS limitation (in
fact, we have to keep extra code to enforce it). But that
would mean a client could force us to allocate an arbitrary
amount of memory simply by sending us "argument" lines. By
limiting the MAX_ARGS, we limit an attacker to about 4
megabytes (64 times a maximum 64K packet buffer). That may
sound like a lot compared to the 4K limit, but it's not a
big deal compared to what git-archive will actually allocate
while working (e.g., to load blobs into memory). The
important thing is that it is bounded.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
According to the comment, enter_repo will modify its input.
However, this has not been the case since 1c64b48
(enter_repo: do not modify input, 2011-10-04). Drop the
now-useless copy.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The POSIX-function fork is not supported on Windows. Use our
start_command API instead, respawning ourselves in a special
"writer" mode to follow the alternate code path.
Remove the NOT_MINGW-prereq for t5000, as git-archive --remote
now works.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The POSIX-function fork is not supported on Windows. Use our
start_command API instead.
As this is the last call-site that depends on the fork-stub in
compat/mingw.h, remove that as well.
Add an undocumented flag to git-archive that tells it that the
action originated from a remote, so features can be disabled.
Thanks to Jeff King for work on this part.
Remove the NOT_MINGW-prereq for t5000, as git-archive --remote
now works.
Signed-off-by: Erik Faye-Lund <kusmabite@gmail.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Some tar filters may be very expensive to run, so sites do
not want to expose them via upload-archive. This patch lets
users configure tar.<filter>.remote to turn them off.
By default, gzip filters are left on, as they are about as
expensive as creating zip archives.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The process for guessing an archive output format based on
the filename is something like this:
a. parse --output in cmd_archive; check the filename
against a static set of mapping heuristics (right now
it just matches ".zip" for zip files).
b. if found, stick a fake "--format=zip" at the beginning
of the arguments list (if the user did specify a
--format manually, the later option will override our
fake one)
c. if it's a remote call, ship the arguments to the remote
(including the fake), which will call write_archive on
their end
d. if it's local, ship the arguments to write_archive
locally
There are two problems:
1. The set of mappings is static and at too high a level.
The write_archive level is going to check config for
user-defined formats, some of which will specify
extensions. We need to delay lookup until those are
parsed, so we can match against them.
2. For a remote archive call, our set of mappings (or
formats) may not match the remote side's. This is OK in
practice right now, because all versions of git
understand "zip" and "tar". But as new formats are
added, there is going to be a mismatch between what the
client can do and what the remote server can do.
To fix (1), this patch refactors the location guessing to
happen at the write_archive level, instead of the
cmd_archive level. So instead of sticking a fake --format
field in the argv list, we actually pass a "name hint" down
the callchain; this hint is used at the appropriate time to
guess the format (if one hasn't been given already).
This patch leaves (2) unfixed. The name_hint is converted to
a "--format" option as before, and passed to the remote.
This means the local side's idea of how extensions map to
formats will take precedence.
Another option would be to pass the name hint to the remote
side and let the remote choose. This isn't a good idea for
two reasons:
1. There's no room in the protocol for passing that
information. We can pass a new argument, but older
versions of git on the server will choke on it.
2. Letting the remote side decide creates a silent
inconsistency in user experience. Consider the case
that the locally installed git knows about the "tar.gz"
format, but a remote server doesn't.
Running "git archive -o foo.tar.gz" will use the tar.gz
format. If we use --remote, and the local side chooses
the format, then we send "--format=tar.gz" to the
remote, which will complain about the unknown format.
But if we let the remote side choose the format, then
it will realize that it doesn't know about "tar.gz" and
output uncompressed tar without even issuing a warning.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This shrinks the top-level directory a bit, and makes it much more
pleasant to use auto-completion on the thing. Instead of
[torvalds@nehalem git]$ em buil<tab>
Display all 180 possibilities? (y or n)
[torvalds@nehalem git]$ em builtin-sh
builtin-shortlog.c builtin-show-branch.c builtin-show-ref.c
builtin-shortlog.o builtin-show-branch.o builtin-show-ref.o
[torvalds@nehalem git]$ em builtin-shor<tab>
builtin-shortlog.c builtin-shortlog.o
[torvalds@nehalem git]$ em builtin-shortlog.c
you get
[torvalds@nehalem git]$ em buil<tab> [type]
builtin/ builtin.h
[torvalds@nehalem git]$ em builtin [auto-completes to]
[torvalds@nehalem git]$ em builtin/sh<tab> [type]
shortlog.c shortlog.o show-branch.c show-branch.o show-ref.c show-ref.o
[torvalds@nehalem git]$ em builtin/sho [auto-completes to]
[torvalds@nehalem git]$ em builtin/shor<tab> [type]
shortlog.c shortlog.o
[torvalds@nehalem git]$ em builtin/shortlog.c
which doesn't seem all that different, but not having that annoying
break in "Display all 180 possibilities?" is quite a relief.
NOTE! If you do this in a clean tree (no object files etc), or using an
editor that has auto-completion rules that ignores '*.o' files, you
won't see that annoying 'Display all 180 possibilities?' message - it
will just show the choices instead. I think bash has some cut-off
around 100 choices or something.
So the reason I see this is that I'm using an odd editory, and thus
don't have the rules to cut down on auto-completion. But you can
simulate that by using 'ls' instead, or something similar.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
