On invocation of a helper a new pipe is opened.
To close the other end after fork, the prexec_cb feature
of the run_command api is used.
If the helper is not used with fast-import later the pipe
is unused.
The FD is passed to the remote-helper via it's environment,
helpers that don't use fast-import can simply ignore it.
fast-import has an argv for that.
Signed-off-by: Florian Achleitner <florian.achleitner.2.6.31@xxxxxxxxx>
---
transport-helper.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
vcs-svn/svndump.c | 9 ++++++++-
2 files changed, 56 insertions(+), 1 deletion(-)
diff --git a/transport-helper.c b/transport-helper.c
index 61c928f..b438040 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -17,6 +17,7 @@ struct helper_data {
const char *name;
struct child_process *helper;
FILE *out;
+ int fast_import_backchannel_pipe[2];
unsigned fetch : 1,
import : 1,
export : 1,
@@ -98,19 +99,30 @@ static void do_take_over(struct transport *transport)
free(data);
}
+static int fd_to_close;
+void close_fd_prexec_cb(void)
+{
+ if(debug)
+ fprintf(stderr, "close_fd_prexec_cb closing %d\n", fd_to_close);
+ close(fd_to_close);
+}
+
static struct child_process *get_helper(struct transport *transport)
{
struct helper_data *data = transport->data;
struct strbuf buf = STRBUF_INIT;
+ struct strbuf envbuf = STRBUF_INIT;
struct child_process *helper;
const char **refspecs = NULL;
int refspec_nr = 0;
int refspec_alloc = 0;
int duped;
int code;
+ int err;
char git_dir_buf[sizeof(GIT_DIR_ENVIRONMENT) + PATH_MAX + 1];
const char *helper_env[] = {
git_dir_buf,
+ NULL, /* placeholder */
NULL
};
@@ -133,6 +145,24 @@ static struct child_process *get_helper(struct transport *transport)
snprintf(git_dir_buf, sizeof(git_dir_buf), "%s=%s", GIT_DIR_ENVIRONMENT, get_git_dir());
helper->env = helper_env;
+
+ /* create an additional pipe from fast-import to the helper */
+ err = pipe(data->fast_import_backchannel_pipe);
+ if(err)
+ die("cannot create fast_import_backchannel_pipe: %s", strerror(errno));
+
+ if(debug)
+ fprintf(stderr, "Remote helper created fast_import_backchannel_pipe { %d, %d }\n",
+ data->fast_import_backchannel_pipe[0], data->fast_import_backchannel_pipe[1]);
+
+ strbuf_addf(&envbuf, "GIT_REPORT_FILENO=%d", data->fast_import_backchannel_pipe[0]);
+ helper_env[1] = strbuf_detach(&envbuf, NULL);
+
+ /* after the fork, we need to close the write end in the helper */
+ fd_to_close = data->fast_import_backchannel_pipe[1];
+ /* the prexec callback is run just before exec */
+ helper->preexec_cb = close_fd_prexec_cb;
+
code = start_command(helper);
if (code < 0 && errno == ENOENT)
die("Unable to find remote helper for '%s'", data->name);
@@ -141,6 +171,7 @@ static struct child_process *get_helper(struct transport *transport)
data->helper = helper;
data->no_disconnect_req = 0;
+ free((void*)helper_env[1]);
/*
* Open the output as FILE* so strbuf_getline() can be used.
@@ -237,6 +268,10 @@ static int disconnect_helper(struct transport *transport)
xwrite(data->helper->in, "\n", 1);
sigchain_pop(SIGPIPE);
}
+ /* close the pipe, it is still open if it wasn't used for fast-import. */
+ close(data->fast_import_backchannel_pipe[0]);
+ close(data->fast_import_backchannel_pipe[1]);
+
close(data->helper->in);
close(data->helper->out);
fclose(data->out);
@@ -376,13 +411,20 @@ static int fetch_with_fetch(struct transport *transport,
static int get_importer(struct transport *transport, struct child_process *fastimport)
{
struct child_process *helper = get_helper(transport);
+ struct helper_data *data = transport->data;
+ struct strbuf buf = STRBUF_INIT;
memset(fastimport, 0, sizeof(*fastimport));
fastimport->in = helper->out;
fastimport->argv = xcalloc(5, sizeof(*fastimport->argv));
fastimport->argv[0] = "fast-import";
fastimport->argv[1] = "--quiet";
+ strbuf_addf(&buf, "--cat-blob-fd=%d", data->fast_import_backchannel_pipe[1]);
+ fastimport->argv[2] = strbuf_detach(&buf, NULL);
fastimport->git_cmd = 1;
+
+ fd_to_close = data->fast_import_backchannel_pipe[0];
+ fastimport->preexec_cb = close_fd_prexec_cb;
return start_command(fastimport);
}
@@ -427,6 +469,11 @@ static int fetch_with_import(struct transport *transport,
if (get_importer(transport, &fastimport))
die("Couldn't run fast-import");
+
+ /* in the parent process we close both pipe ends. */
+ close(data->fast_import_backchannel_pipe[0]);
+ close(data->fast_import_backchannel_pipe[1]);
+
for (i = 0; i < nr_heads; i++) {
posn = to_fetch[i];
if (posn->status & REF_STATUS_UPTODATE)
@@ -441,6 +488,7 @@ static int fetch_with_import(struct transport *transport,
if (finish_command(&fastimport))
die("Error while running fast-import");
+ free((void*)fastimport.argv[2]);
free(fastimport.argv);
fastimport.argv = NULL;
diff --git a/vcs-svn/svndump.c b/vcs-svn/svndump.c
index 2f0089f..b1fe03f 100644
--- a/vcs-svn/svndump.c
+++ b/vcs-svn/svndump.c
@@ -467,7 +467,14 @@ void svndump_read(const char *url)
static void init()
{
- fast_export_init(REPORT_FILENO);
+ int report_fd;
+ char* back_fd_env = getenv("GIT_REPORT_FILENO");
+ if(!back_fd_env || sscanf(back_fd_env, "%d", &report_fd) != 1) {
+ warning("Cannot get cat-blob fd from environment, using default!");
+ report_fd = REPORT_FILENO;
+ }
+
+ fast_export_init(report_fd);
strbuf_init(&dump_ctx.uuid, 4096);
strbuf_init(&dump_ctx.url, 4096);
strbuf_init(&rev_ctx.log, 4096);
--
1.7.9.5
--
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