[PATCH 1/1] mingw: optionally disable side-band-64k for transport
From: Thomas Braun <thomas.braun@byte-physics.de>
Since commit 0c499ea60f (send-pack: demultiplex a sideband stream with status data, 2010-02-05) the built-in send-pack uses the side-band-64k capability if advertised by the server.
Unfortunately this breaks pushing over the dump git protocol if used over a network connection when using MinGW (but *not* when using mingw-w64).
The detailed reasons for this, are courtesy of Jeff Preshing, quoted from https://groups.google.com/d/msg/msysgit/at8D7J-h7mw/eaLujILGUWoJ:
MinGW wraps Windows sockets in CRT file descriptors in order to
mimic the functionality of POSIX sockets. This causes msvcrt.dll
to treat sockets as Installable File System (IFS) handles,
calling ReadFile, WriteFile, DuplicateHandle and CloseHandle on
them. This approach works well in simple cases on recent
versions of Windows, but does not support all usage patterns.
In particular, using this approach, any attempt to read & write
concurrently on the same socket (from one or more processes)
will deadlock in a scenario where the read waits for a response
from the server which is only invoked after the write. This is
what send_pack currently attempts to do in the use_sideband
codepath.
The new config option "sendpack.sideband" allows to override the side-band-64k capability of the server, and thus makes the dump git protocol work.
As this only affects builds against MinGW, the default is still to use side band.
[jes: split out the documentation into Documentation/config/, touched up the commit message.]
Signed-off-by: Thomas Braun <thomas.braun@byte-physics.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
Documentation/config.txt | 2 ++
Documentation/config/sendpack.txt | 5 +++++
send-pack.c | 14 +++++++++++++-
3 files changed, 20 insertions(+), 1 deletion(-)
create mode 100644 Documentation/config/sendpack.txt
Show changes to 3 files +20 −1
Documentation/config.txt, Documentation/config/sendpack.txt, send-pack.c
diff --git a/Documentation/config.txt b/Documentation/config.txt
index d87846faa6..e9b2d10e99 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -406,6 +406,8 @@ include::config/reset.txt[]
include::config/sendemail.txt[]
+include::config/sendpack.txt[]
+
include::config/sequencer.txt[]
include::config/showbranch.txt[]
diff --git a/Documentation/config/sendpack.txt b/Documentation/config/sendpack.txt
new file mode 100644
index 0000000000..e306f657fb
--- /dev/null
+++ b/Documentation/config/sendpack.txt
@@ -0,0 +1,5 @@
+sendpack.sideband::
+ Allows to disable the side-band-64k capability for send-pack even
+ when it is advertised by the server. Makes it possible to work
+ around a limitation in the git for windows implementation together
+ with the dump git protocol. Defaults to true.
diff --git a/send-pack.c b/send-pack.c
index 6dc16c3211..fa9e8cf1fc 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -38,6 +38,16 @@ int option_parse_push_signed(const struct option *opt,
die("bad %s argument: %s", opt->long_name, arg);
}
+static int config_use_sideband = 1;
+
+static int send_pack_config(const char *var, const char *value, void *unused)
+{
+ if (!strcmp("sendpack.sideband", var))
+ config_use_sideband = git_config_bool(var, value);
+
+ return 0;
+}
+
static void feed_object(const struct object_id *oid, FILE *fh, int negative)
{
if (negative && !has_object_file(oid))
@@ -390,6 +400,8 @@ int send_pack(struct send_pack_args *args,
const char *push_cert_nonce = NULL;
struct packet_reader reader;
+ git_config(send_pack_config, NULL);
+
/* Does the other end support the reporting? */
if (server_supports("report-status"))
status_report = 1;
@@ -397,7 +409,7 @@ int send_pack(struct send_pack_args *args,
allow_deleting_refs = 1;
if (server_supports("ofs-delta"))
args->use_ofs_delta = 1;
- if (server_supports("side-band-64k"))
+ if (config_use_sideband && server_supports("side-band-64k"))
use_sideband = 1;
if (server_supports("quiet"))
quiet_supported = 1;
--
gitgitgadget
Johannes Schindelin via GitGitGadget
