[RFC PATCH v2 0/2] Two new remote helpers

@@ -702,6 +702,7 @@ BUILTIN_OBJS += builtin/read-tree.o
 BUILTIN_OBJS += builtin/receive-pack.o
 BUILTIN_OBJS += builtin/reflog.o
 BUILTIN_OBJS += builtin/remote.o
+BUILTIN_OBJS += builtin/remote-fd.o
 BUILTIN_OBJS += builtin/replace.o
 BUILTIN_OBJS += builtin/rerere.o
 BUILTIN_OBJS += builtin/reset.o

@@ -138,5 +138,6 @@ extern int cmd_verify_pack(int argc, const char **argv, const char *prefix);
 extern int cmd_show_ref(int argc, const char **argv, const char *prefix);
 extern int cmd_pack_refs(int argc, const char **argv, const char *prefix);
 extern int cmd_replace(int argc, const char **argv, const char *prefix);
+extern int cmd_remote_fd(int argc, const char **argv, const char *prefix);
 
 #endif

@@ -0,0 +1,88 @@
+#include "git-compat-util.h"
+#include "transport.h"
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+
+
+/*
+ * URL syntax:
+ *	'fd::<inoutfd>[/<anything>]'		Read/write socket pair
+ *						<inoutfd>.
+ *	'fd::<infd>,<outfd>[/<anything>]'	Read pipe <infd> and write
+ *						pipe <outfd>.
+ *	[foo] indicates 'foo' is optional. <anything> is any string.
+ *
+ * The data output to <outfd>/<inoutfd> should be passed unmolested to
+ * git-receive-pack/git-upload-pack/git-upload-archive and output of
+ * git-receive-pack/git-upload-pack/git-upload-archive should be passed
+ * unmolested to <infd>/<inoutfd>.
+ *
+ */
+
+int input_fd = -1;
+int output_fd = -1;
+
+#define MAXCOMMAND 4096
+
+static int command_loop()
+{
+	char buffer[MAXCOMMAND];
+
+	while (1) {
+		if (!fgets(buffer, MAXCOMMAND - 1, stdin))
+			exit(0);
+		//Strip end of line characters.
+		while (isspace((unsigned char)buffer[strlen(buffer) - 1]))
+			buffer[strlen(buffer) - 1] = 0;
+
+		if (!strcmp(buffer, "capabilities")) {
+			printf("*connect\n\n");
+			fflush(stdout);
+		} else if (!strncmp(buffer, "connect ", 8)) {
+			printf("\n");
+			fflush(stdout);
+			return bidirectional_transfer_loop(input_fd,
+				output_fd);
+		} else {
+			fprintf(stderr, "Bad command");
+			return 1;
+		}
+	}
+}
+
+int cmd_remote_fd(int argc, const char **argv, const char *prefix)
+{
+	char* end;
+	unsigned long r;
+
+	if (argc < 3) {
+		fprintf(stderr, "Error: URL missing");
+		exit(1);
+	}
+
+	r = strtoul(argv[2], &end, 10);
+	input_fd = (int)r;
+
+	if ((*end != ',' && *end !='/' && *end) || end == argv[2]) {
+		fprintf(stderr, "Error: Bad URL syntax");
+		exit(1);
+	}
+
+	if (*end == '/' || !*end) {
+		output_fd = input_fd;
+	} else {
+		char* end2;
+		r = strtoul(end + 1, &end2, 10);
+		output_fd = (int)r;
+
+		if ((*end2 !='/' && *end2) || end2 == end + 1) {
+			fprintf(stderr, "Error: Bad URL syntax");
+			exit(1);
+		}
+	}
+
+	return command_loop();
+}

@@ -368,6 +368,7 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "receive-pack", cmd_receive_pack },
 		{ "reflog", cmd_reflog, RUN_SETUP },
 		{ "remote", cmd_remote, RUN_SETUP },
+		{ "remote-fd", cmd_remote_fd, 0 },
 		{ "replace", cmd_replace, RUN_SETUP },
 		{ "repo-config", cmd_config },
 		{ "rerere", cmd_rerere, RUN_SETUP },

@@ -862,3 +862,133 @@ int transport_helper_init(struct transport *transport, const char *name)
 	transport->smart_options = &(data->transport_options);
 	return 0;
 }
+
+
+#define BUFFERSIZE 4096
+
+/* Copy data from stdin to output and from input to stdout. */
+int bidirectional_transfer_loop(int input, int output)
+{
+	struct pollfd polls[4];
+	char in_buffer[BUFFERSIZE];
+	char out_buffer[BUFFERSIZE];
+	size_t in_buffer_use = 0;
+	size_t out_buffer_use = 0;
+	int in_hup = 0;
+	int out_hup = 0;
+	int socket_mode = 0;
+	int input_index = 2;
+	int output_index = 3;
+	int poll_count = 4;
+
+	if(input == output) {
+		output_index = input_index;
+		poll_count = 3;
+		socket_mode = 1;
+	}
+
+	while(in_buffer_use || out_buffer_use || !in_hup || !out_hup) {
+		int r, i;
+		/* Set up the poll and do it. */
+		polls[0].fd = 0;
+		polls[1].fd = 1;
+		polls[input_index].fd = input;
+		polls[output_index].fd = output;
+		for(i = 0; i < 4; i++)
+			polls[i].events = polls[i].revents = 0;
+
+		if(in_buffer_use > 0)
+			polls[output_index].events |= POLLOUT;
+		if(in_buffer_use < BUFFERSIZE && !in_hup)
+			polls[0].events |= POLLIN;
+		if(out_buffer_use > 0)
+			polls[1].events |= POLLOUT;
+		if(out_buffer_use < BUFFERSIZE && !out_hup)
+			polls[input_index].events |= POLLIN;
+		r = poll(polls, poll_count, -1);
+		if(r < 0) {
+			if(errno == EWOULDBLOCK || errno == EAGAIN ||
+				errno == EINTR)
+				continue;
+			perror("poll failed");
+			return 1;
+		} else if(r == 0)
+			continue;
+
+		/* Something interesting has happened... */
+		if(polls[0].revents & (POLLIN | POLLHUP)) {
+			/* Stdin is readable. */
+			r = read(0, in_buffer + in_buffer_use, BUFFERSIZE -
+				in_buffer_use);
+			if(r < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
+				errno != EINTR) {
+				perror("read(git) failed");
+				return 1;
+			} else if(r == 0) {
+				in_hup = 1;
+				if(!in_buffer_use) {
+					if(socket_mode)
+						shutdown(output, SHUT_WR);
+					else
+						close(output);
+				}
+			} else
+				in_buffer_use += r;
+		}
+
+		if(polls[input_index].revents & (POLLIN | POLLHUP)) {
+			/* Connection is readable. */
+			r = read(input, out_buffer + out_buffer_use,
+				BUFFERSIZE - out_buffer_use);
+			if(r < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
+				errno != EINTR) {
+				perror("read(connection) failed");
+				return 1;
+			} else if(r == 0) {
+				out_hup = 1;
+				if(!out_buffer_use)
+					close(1);
+			} else
+				out_buffer_use += r;
+		}
+
+		if(polls[1].revents & POLLOUT) {
+			/* Stdout is writable. */
+			r = write(1, out_buffer, out_buffer_use);
+			if(r < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
+				errno != EINTR) {
+				perror("write(git) failed");
+				return 1;
+			} else {
+				out_buffer_use -= r;
+				if(out_buffer_use > 0)
+					memmove(out_buffer, out_buffer + r,
+						out_buffer_use);
+				if(out_hup && !out_buffer_use)
+					close(1);
+			}
+		}
+
+		if(polls[output_index].revents & POLLOUT) {
+			/* Connection is writable. */
+			r = write(output, in_buffer, in_buffer_use);
+			if(r < 0 && errno != EWOULDBLOCK && errno != EAGAIN &&
+				errno != EINTR) {
+				perror("write(connection) failed");
+				return 1;
+			} else {
+				in_buffer_use -= r;
+				if(in_buffer_use > 0)
+					memmove(in_buffer, in_buffer + r,
+						in_buffer_use);
+				if(in_hup && !in_buffer_use) {
+					if(socket_mode)
+						shutdown(output, SHUT_WR);
+					else
+						close(output);
+				}
+			}
+		}
+	}
+	return 0;
+}

@@ -154,6 +154,7 @@ int transport_connect(struct transport *transport, const char *name,
 
 /* Transport methods defined outside transport.c */
 int transport_helper_init(struct transport *transport, const char *name);
+int bidirectional_transfer_loop(int input, int output);
 
 /* common methods used by transport.c and builtin-send-pack.c */
 void transport_verify_remote_names(int nr_heads, const char **heads);

@@ -702,6 +702,7 @@ BUILTIN_OBJS += builtin/read-tree.o
 BUILTIN_OBJS += builtin/receive-pack.o
 BUILTIN_OBJS += builtin/reflog.o
 BUILTIN_OBJS += builtin/remote.o
+BUILTIN_OBJS += builtin/remote-ext.o
 BUILTIN_OBJS += builtin/remote-fd.o
 BUILTIN_OBJS += builtin/replace.o
 BUILTIN_OBJS += builtin/rerere.o

@@ -139,5 +139,6 @@ extern int cmd_show_ref(int argc, const char **argv, const char *prefix);
 extern int cmd_pack_refs(int argc, const char **argv, const char *prefix);
 extern int cmd_replace(int argc, const char **argv, const char *prefix);
 extern int cmd_remote_fd(int argc, const char **argv, const char *prefix);
+extern int cmd_remote_ext(int argc, const char **argv, const char *prefix);
 
 #endif

@@ -0,0 +1,300 @@
+#include "git-compat-util.h"
+#include "transport.h"
+#include "run-command.h"
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <unistd.h>
+
+/*
+ * URL syntax:
+ *	'command [arg1 [arg2 [...]]]'	Invoke command with given arguments.
+ *	Special characters:
+ *	'\ ': Literal space in argument.
+ *	'\\': Literal backslash.
+ *	'\S': Name of service (git-upload-pack/git-upload-archive/
+ *		git-receive-pack.
+ *	'\s': Same as \s, but with possible git- prefix stripped.
+ *	'\G': Only allowed as first 'character' of argument. Do not pass this
+ *		Argument to command, instead send this as name of repository
+ *		in in-line git://-style request (also activates sending this
+ *		style of request).
+ *	'\V': Only allowed as first 'character' of argument. Used in
+ *		conjunction with '\G': Do not pass this argument to command,
+ *		instead send this as vhost in git://-style request (note: does
+ *		not activate sending git:// style request).
+ */
+
+char* git_req = NULL;
+char* git_req_vhost = NULL;
+
+static char *strip_escapes(const char *str, const char *service,
+	const char **next)
+{
+	char *ret;
+	size_t rpos = 0;
+	size_t wpos = 0;
+	size_t finallen = 0;
+	int escape = 0;
+	char special = 0;
+	size_t pslen = 0;
+	size_t pSlen = 0;
+	size_t psoff = 0;
+
+	/* Calculate prefix length for \s and lengths for \s and \S */
+	if (!strncmp(service, "git-", 4))
+		psoff = 4;
+	pSlen = strlen(service);
+	pslen = pSlen - psoff;
+
+	/* Calculate output length and start of next argument. */
+	while (str[rpos] && (escape || str[rpos] != ' ')) {
+		if (escape) {
+			switch (str[rpos]) {
+			case ' ':
+			case '\\':
+				finallen++;
+				break;
+			case 's':
+				finallen += pslen;
+				break;
+			case 'S':
+				finallen += pSlen;
+				break;
+			case 'G':
+			case 'V':
+				special = str[rpos];
+				if (rpos == 1)
+					break;
+				/* Fall-through to error. */
+			default:
+				die("Bad remote-ext placeholder '\\%c'.",
+					str[rpos]);
+			}
+			escape = 0;
+		} else
+			switch (str[rpos]) {
+			case '\\':
+				escape = 1;
+				break;
+			default:
+				finallen++;
+				break;
+			}
+		rpos++;
+	}
+	if (escape && !str[rpos])
+		die("remote-ext command has incomplete placeholder");
+	*next = str + rpos;
+	if (**next == ' ')
+		++*next;	/* Skip over space */
+
+	/*
+	 * Do the actual placeholder substitution. The string will be short
+	 * enough not to overflow integers.
+	 */
+	ret = xmalloc(finallen + 1);
+	rpos = special ? 2 : 0;		/* Skip first 2 bytes in specials. */
+	escape = 0;
+	while (str[rpos] && (escape || str[rpos] != ' ')) {
+		if (escape) {
+			switch(str[rpos]) {
+			case ' ':
+			case '\\':
+				ret[wpos++] = str[rpos];
+				break;
+			case 's':
+				strcpy(ret + wpos, service + psoff);
+				wpos += pslen;
+				break;
+			case 'S':
+				strcpy(ret + wpos, service);
+				wpos += pSlen;
+				break;
+			}
+			escape = 0;
+		} else
+			switch(str[rpos]) {
+			case '\\':
+				escape = 1;
+				break;
+			default:
+				ret[wpos++] = str[rpos];
+				break;
+			}
+		rpos++;
+	}
+	ret[wpos] = 0;
+	switch(special) {
+	case 'G':
+		git_req = ret;
+		return NULL;
+	case 'V':
+		git_req_vhost = ret;
+		return NULL;
+	default:
+		return ret;
+	}
+}
+
+/* Should be enough... */
+#define MAXARGUMENTS 256
+
+static const char **parse_argv(const char *arg, const char *service)
+{
+	int arguments = 0;
+	int i;
+	char** ret;
+	char *(temparray[MAXARGUMENTS + 1]);
+
+	while (*arg) {
+		char* ret;
+		if (arguments == MAXARGUMENTS)
+			die("remote-ext command has too many arguments");
+		ret = strip_escapes(arg, service, &arg);
+		if (ret)
+			temparray[arguments++] = ret;
+	}
+
+	ret = xcalloc(arguments + 1, sizeof(char*));
+	for (i = 0; i < arguments; i++)
+		ret[i] = temparray[i];
+
+	return (const char**)ret;
+}
+
+static void send_git_request(int stdin_fd, const char *serv, const char *repo,
+	const char *vhost)
+{
+	size_t bufferspace;
+	size_t wpos = 0;
+	size_t spos = 0;
+	size_t tmp;
+	char* buffer;
+
+	/*
+	 * Request needs 12 bytes extra if there is vhost (xxxx \0host=\0) and
+	 * 6 bytes extra (xxxx \0) if there is no vhost.
+	 */
+	if (vhost)
+		bufferspace = strlen(serv) + strlen(repo) + strlen(vhost) + 12;
+	else
+		bufferspace = strlen(serv) + strlen(repo) + 6;
+
+	if (bufferspace > 0xFFFF)
+		die("Request too large to send");
+	buffer = xmalloc(bufferspace);
+
+	/* Packet length. */
+	sprintf(buffer + wpos, "%04x", (unsigned)bufferspace);
+	wpos += 4;
+
+	/* Service. */
+	tmp = strlen(serv);
+	memcpy(buffer + wpos, serv, tmp);
+	wpos += tmp;
+
+	/* Space. */
+	buffer[wpos++] = ' ';
+
+	/* Repo. */
+	tmp = strlen(repo);
+	memcpy(buffer + wpos, repo, tmp);
+	wpos += tmp;
+
+	/* NUL. */
+	buffer[wpos++] = '\0';
+
+	/* Vhost if any. */
+	if (vhost) {
+		/* Header name. */
+		strcpy(buffer + wpos, "host=");
+		wpos += 5;
+
+		/* Actual vhost */
+		tmp = strlen(vhost);
+		memcpy(buffer + wpos, vhost, tmp);
+		wpos += tmp;
+
+		/* NUL. */
+		buffer[wpos++] = '\0';
+	}
+
+	/* Send the request */
+	while (spos < wpos) {
+		ssize_t r;
+		r = write(stdin_fd, buffer + spos, wpos - spos);
+		if (r < 0 && errno != EINTR && errno != EAGAIN &&
+			errno != EWOULDBLOCK)
+			die_errno("Failed to send request");
+		else if (r < 0)
+			continue;	/* Try again. */
+		else
+			spos += r;
+	}
+
+	free(buffer);
+}
+
+static int run_child(const char *arg, const char *service)
+{
+	int r;
+	struct child_process child;
+
+	memset(&child, 0, sizeof(child));
+	child.in = -1;
+	child.out = -1;
+	child.err = 0;
+	child.argv = parse_argv(arg, service);
+
+	if (start_command(&child) < 0)
+		die("Can't run specified command");
+
+	if (git_req)
+		send_git_request(child.in, service, git_req, git_req_vhost);
+
+	r = bidirectional_transfer_loop(child.out, child.in);
+	if (!r)
+		r = finish_command(&child);
+	else
+		finish_command(&child);
+	return r;
+}
+
+#define MAXCOMMAND 4096
+
+static int command_loop(const char *child)
+{
+	char buffer[MAXCOMMAND];
+
+	while (1) {
+		if (!fgets(buffer, MAXCOMMAND - 1, stdin))
+			exit(0);
+		//Strip end of line characters.
+		while (isspace((unsigned char)buffer[strlen(buffer) - 1]))
+			buffer[strlen(buffer) - 1] = 0;
+
+		if (!strcmp(buffer, "capabilities")) {
+			printf("*connect\n\n");
+			fflush(stdout);
+		} else if (!strncmp(buffer, "connect ", 8)) {
+			printf("\n");
+			fflush(stdout);
+			return run_child(child, buffer + 8);
+		} else {
+			fprintf(stderr, "Bad command");
+			return 1;
+		}
+	}
+}
+
+int cmd_remote_ext(int argc, const char **argv, const char *prefix)
+{
+	if (argc < 3) {
+		fprintf(stderr, "Error: URL missing");
+		exit(1);
+	}
+
+	return command_loop(argv[2]);
+}

@@ -368,6 +368,7 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "receive-pack", cmd_receive_pack },
 		{ "reflog", cmd_reflog, RUN_SETUP },
 		{ "remote", cmd_remote, RUN_SETUP },
+		{ "remote-ext", cmd_remote_ext, 0 },
 		{ "remote-fd", cmd_remote_fd, 0 },
 		{ "replace", cmd_replace, RUN_SETUP },
 		{ "repo-config", cmd_config },