From baf7b6b55dd4674aa92c47a52c52e60d63072569 Mon Sep 17 00:00:00 2001 From: Thomas Braun Date: Thu, 8 May 2014 21:43:24 +0200 Subject: [PATCH] Config option to disable side-band-64k for transport Since commit 0c499ea60f the send-pack builtin 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. The detailed reasons for this breakage are (by courtesy of Jeff Preshing, quoted from ttps://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. Other transportation methods like ssh and http/https still benefit from the sideband channel, therefore the default value of "sendpack.sideband" is still true. [jes: split out the documentation into Documentation/config/] Signed-off-by: Thomas Braun Signed-off-by: Johannes Schindelin --- 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 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;