patch, 2 partsrsync support

dir.c, dir.h, refs.c

diff --git a/dir.c b/dir.c
index eb6c3ab..0fae400 100644
--- a/dir.c
+++ b/dir.c
@@ -685,3 +685,48 @@ int is_inside_dir(const char *dir)
 	char buffer[PATH_MAX];
 	return get_relative_cwd(buffer, sizeof(buffer), dir) != NULL;
 }
+
+int remove_dir_recursively(char *path, int len, int only_empty)
+{
+	DIR *dir = opendir(path);
+	struct dirent *e;
+	int ret = 0;
+
+	if (!dir)
+		return -1;
+	if (path[len-1] != '/')
+		path[len++] = '/';
+	while ((e = readdir(dir)) != NULL) {
+		struct stat st;
+		int namlen;
+		if ((e->d_name[0] == '.') &&
+		    ((e->d_name[1] == 0) ||
+		     ((e->d_name[1] == '.') && e->d_name[2] == 0)))
+			continue; /* "." and ".." */
+
+		namlen = strlen(e->d_name);
+		if (len + namlen > PATH_MAX ||
+				!memcpy(path + len, e->d_name, namlen) ||
+				(path[len + namlen] = '\0') ||
+				lstat(path, &st))
+			; /* fall thru */
+		else if (S_ISDIR(st.st_mode)) {
+			if (!remove_dir_recursively(path, len + namlen,
+						only_empty))
+				continue; /* happy */
+		} else if (!only_empty &&
+				len + namlen + 1 < PATH_MAX &&
+				!unlink(path))
+			continue; /* happy, too */
+
+		/* path too long, stat fails, or non-directory still exists */
+		ret = -1;
+		break;
+	}
+	closedir(dir);
+	if (!ret) {
+		path[len] = 0;
+		ret = rmdir(path);
+	}
+	return ret;
+}
diff --git a/dir.h b/dir.h
index f55a87b..f52eea8 100644
--- a/dir.h
+++ b/dir.h
@@ -64,4 +64,6 @@ extern struct dir_entry *dir_add_name(struct dir_struct *dir, const char *pathna
 extern char *get_relative_cwd(char *buffer, int size, const char *dir);
 extern int is_inside_dir(const char *dir);
 
+extern int remove_dir_recursively(char *dir, int len, int only_empty);
+
 #endif
diff --git a/refs.c b/refs.c
index 07e260c..f0336ee 100644
--- a/refs.c
+++ b/refs.c
@@ -2,6 +2,7 @@
 #include "refs.h"
 #include "object.h"
 #include "tag.h"
+#include "dir.h"
 
 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
 #define REF_KNOWS_PEELED 04
@@ -673,40 +674,7 @@ static struct ref_lock *verify_lock(struct ref_lock *lock,
 
 static int remove_empty_dir_recursive(char *path, int len)
 {
-	DIR *dir = opendir(path);
-	struct dirent *e;
-	int ret = 0;
-
-	if (!dir)
-		return -1;
-	if (path[len-1] != '/')
-		path[len++] = '/';
-	while ((e = readdir(dir)) != NULL) {
-		struct stat st;
-		int namlen;
-		if ((e->d_name[0] == '.') &&
-		    ((e->d_name[1] == 0) ||
-		     ((e->d_name[1] == '.') && e->d_name[2] == 0)))
-			continue; /* "." and ".." */
-
-		namlen = strlen(e->d_name);
-		if ((len + namlen < PATH_MAX) &&
-		    strcpy(path + len, e->d_name) &&
-		    !lstat(path, &st) &&
-		    S_ISDIR(st.st_mode) &&
-		    !remove_empty_dir_recursive(path, len + namlen))
-			continue; /* happy */
-
-		/* path too long, stat fails, or non-directory still exists */
-		ret = -1;
-		break;
-	}
-	closedir(dir);
-	if (!ret) {
-		path[len] = 0;
-		ret = rmdir(path);
-	}
-	return ret;
+	return remove_dir_recursively(path, len, 1);
 }
 
 static int remove_empty_directories(char *file)

t/t5510-fetch.sh, transport.c

diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 439430f..73a4e3c 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -153,4 +153,39 @@ test_expect_success 'bundle should be able to create a full history' '
 
 '
 
+test "$TEST_RSYNC" && {
+test_expect_success 'fetch via rsync' '
+	git pack-refs &&
+	mkdir rsynced &&
+	cd rsynced &&
+	git init &&
+	git fetch rsync://127.0.0.1$(pwd)/../.git master:refs/heads/master &&
+	git gc --prune &&
+	test $(git rev-parse master) = $(cd .. && git rev-parse master) &&
+	git fsck --full
+'
+
+test_expect_success 'push via rsync' '
+	mkdir ../rsynced2 &&
+	(cd ../rsynced2 &&
+	 git init) &&
+	git push rsync://127.0.0.1$(pwd)/../rsynced2/.git master &&
+	cd ../rsynced2 &&
+	git gc --prune &&
+	test $(git rev-parse master) = $(cd .. && git rev-parse master) &&
+	git fsck --full
+'
+
+test_expect_success 'push via rsync' '
+	cd .. &&
+	mkdir rsynced3 &&
+	(cd rsynced3 &&
+	 git init) &&
+	git push --all rsync://127.0.0.1$(pwd)/rsynced3/.git &&
+	cd rsynced3 &&
+	test $(git rev-parse master) = $(cd .. && git rev-parse master) &&
+	git fsck --full
+'
+}
+
 test_done
diff --git a/transport.c b/transport.c
index 4f9cddc..d50a311 100644
--- a/transport.c
+++ b/transport.c
@@ -6,6 +6,334 @@
 #include "fetch-pack.h"
 #include "walker.h"
 #include "bundle.h"
+#include "dir.h"
+#include "refs.h"
+
+/* rsync support */
+
+/*
+ * We copy packed-refs and refs/ into a temporary file, then read the
+ * loose refs recursively (sorting whenever possible), and then inserting
+ * those packed refs that are not yet in the list (not validating, but
+ * assuming that the file is sorted).
+ *
+ * Appears refactoring this from refs.c is too cumbersome.
+ */
+
+static int direntry_cmp(const void *a, const void *b)
+{
+	const struct dirent *d1 = a;
+	const struct dirent *d2 = b;
+
+	return strcmp(d1->d_name, d2->d_name);
+}
+
+/*
+ * path is assumed to point to a buffer of PATH_MAX bytes, and
+ * path + name_offset is expected to point to "refs/".
+ */
+
+static int read_loose_refs(char *path, int name_offset, struct ref **tail)
+{
+	DIR *dir = opendir(path);
+	struct dirent *de;
+	struct {
+		struct dirent *entries;
+		int nr, alloc;
+	} list;
+	int i, pathlen;
+
+	if (!dir)
+		return -1;
+
+	memset (&list, 0, sizeof(list));
+
+	while ((de = readdir(dir))) {
+		if (de->d_name[0] == '.' && (de->d_name[1] == '\0' ||
+				(de->d_name[1] == '.' &&
+				 de->d_name[2] == '\0')))
+			continue;
+		if (list.nr >= list.alloc) {
+			list.alloc = alloc_nr(list.nr);
+			list.entries = xrealloc(list.entries,
+				list.alloc * sizeof(*de));
+		}
+		list.entries[list.nr++] = *de;
+	}
+	closedir(dir);
+
+	/* sort the list */
+
+	qsort(list.entries, list.nr, sizeof(*de), direntry_cmp);
+
+	pathlen = strlen(path);
+	path[pathlen] = '/';
+
+	for (i = 0; i < list.nr; i++) {
+		strlcpy(path + pathlen + 1, list.entries[i].d_name,
+				PATH_MAX - pathlen - 1);
+		if (read_loose_refs(path, name_offset, tail)) {
+			int fd = open(path, O_RDONLY);
+			char buffer[40];
+			struct ref *next;
+
+			if (fd < 0)
+				continue;
+			next = alloc_ref(strlen(path + name_offset));
+			if (read_in_full(fd, buffer, 40) != 40 ||
+					get_sha1_hex(buffer, next->old_sha1)) {
+				free(next);
+				continue;
+			}
+			close(fd);
+			strcpy(next->name, path + name_offset);
+			(*tail)->next = next;
+			*tail = next;
+		}
+	}
+
+	path[pathlen] = '\0';
+
+	free(list.entries);
+	return 0;
+}
+
+/* insert the packed refs for which no loose refs were found */
+
+static void insert_packed_refs(const char *packed_refs, struct ref **list)
+{
+	FILE *f = fopen(packed_refs, "r");
+	static char buffer[PATH_MAX];
+
+	if (!f)
+		return;
+
+	for (;;) {
+		int cmp, len;
+
+		if (!fgets(buffer, sizeof(buffer), f)) {
+			fclose(f);
+			return;
+		}
+
+		if (hexval(buffer[0]) & 0x10)
+			continue;
+		len = strlen(buffer);
+		if (buffer[len - 1] == '\n')
+			buffer[--len] = '\0';
+		if (len < 41)
+			continue;
+		while ((*list)->next &&
+				(cmp = strcmp(buffer + 41,
+				      (*list)->next->name)) > 0)
+			list = &(*list)->next;
+		if (!(*list)->next || cmp < 0) {
+			struct ref *next = alloc_ref(len - 40);
+			buffer[40] = '\0';
+			if (get_sha1_hex(buffer, next->old_sha1)) {
+				warning ("invalid SHA-1: %s", buffer);
+				free(next);
+				continue;
+			}
+			strcpy(next->name, buffer + 41);
+			next->next = (*list)->next;
+			(*list)->next = next;
+			list = &(*list)->next;
+		}
+	}
+}
+
+static struct ref *get_refs_via_rsync(const struct transport *transport)
+{
+	char buffer[PATH_MAX];
+	struct strbuf buf = STRBUF_INIT;
+	struct ref dummy, *result = &dummy;
+	struct child_process rsync;
+	const char *args[5];
+	char *temp_dir;
+
+	/* copy the refs to the temporary directory */
+
+	temp_dir = mkdtemp(git_path("rsync-refs-XXXXXX"));
+	if (temp_dir == NULL)
+		die ("Could not make temporary directory");
+	temp_dir = strcpy(buffer, temp_dir);
+
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addstr(&buf, "/refs");
+
+	memset(&rsync, 0, sizeof(rsync));
+	rsync.argv = args;
+	rsync.stdout_to_stderr = 1;
+	args[0] = "rsync";
+	args[1] = transport->verbose ? "-rv" : "-r";
+	args[2] = buf.buf;
+	args[3] = temp_dir;
+	args[4] = NULL;
+
+	if (run_command(&rsync))
+		die ("Could not run rsync to get refs");
+
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addstr(&buf, "/packed-refs");
+
+	args[2] = buf.buf;
+
+	if (run_command(&rsync))
+		die ("Could not run rsync to get refs");
+
+	/* read the copied refs */
+
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, temp_dir);
+	strbuf_addstr(&buf, "/refs");
+	read_loose_refs(buf.buf, strlen(buf.buf) - 4, &result);
+
+	result = &dummy;
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, temp_dir);
+	strbuf_addstr(&buf, "/packed-refs");
+	insert_packed_refs(buf.buf, &result);
+
+	if (remove_dir_recursively(temp_dir, strlen(temp_dir), 0))
+		warning ("Could not remove temporary directory %s.", temp_dir);
+
+	return dummy.next;
+}
+
+static int fetch_objs_via_rsync(struct transport *transport,
+				 int nr_objs, struct ref **to_fetch)
+{
+	struct strbuf buf = STRBUF_INIT;
+	struct child_process rsync;
+	const char *args[8];
+
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addstr(&buf, "/objects/");
+
+	memset(&rsync, 0, sizeof(rsync));
+	rsync.argv = args;
+	rsync.stdout_to_stderr = 1;
+	args[0] = "rsync";
+	args[1] = transport->verbose ? "-rv" : "-r";
+	args[2] = "--ignore-existing";
+	args[3] = "--exclude";
+	args[4] = "info";
+	args[5] = buf.buf;
+	args[6] = get_object_directory();
+	args[7] = NULL;
+
+	/* NEEDSWORK: handle one level of alternates */
+	return run_command(&rsync);
+}
+
+static int write_one_ref(const char *name, const unsigned char *sha1,
+		int flags, void *data)
+{
+	struct strbuf *buf = data;
+	int len = buf->len;
+	FILE *f;
+
+	if (flags && prefixcmp(name, "refs/heads/") &&
+			prefixcmp(name, "refs/tags/"))
+		return 0;
+
+	strbuf_addstr(buf, name);
+	if (safe_create_leading_directories(buf->buf) ||
+			!(f = fopen(buf->buf, "w")) ||
+			!fwrite(sha1_to_hex(sha1), 40, 1, f) ||
+			fputc('\n', f) == EOF ||
+			fclose(f))
+		return error("problems writing temporary file %s", buf->buf);
+	strbuf_setlen(buf, len);
+	return 0;
+}
+
+static int write_refs_to_temp_dir(struct strbuf *temp_dir,
+		int refspec_nr, const char **refspec)
+{
+	int i;
+
+	for (i = 0; i < refspec_nr; i++) {
+		unsigned char sha1[20];
+		char *ref;
+
+		if (dwim_ref(refspec[i], strlen(refspec[i]), sha1, &ref) != 1)
+			return error("Could not get ref %s", refspec[i]);
+
+		if (write_one_ref(ref, sha1, 0, temp_dir)) {
+			free(ref);
+			return -1;
+		}
+		free(ref);
+	}
+	return 0;
+}
+
+static int rsync_transport_push(struct transport *transport,
+		int refspec_nr, const char **refspec, int flags) {
+	char buffer[PATH_MAX];
+	struct strbuf buf = STRBUF_INIT;
+	int result = 0, i;
+	struct child_process rsync;
+	const char *args[8];
+	char *temp_dir;
+
+	/* first push the objects */
+
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addch(&buf, '/');
+
+	memset(&rsync, 0, sizeof(rsync));
+	rsync.argv = args;
+	rsync.stdout_to_stderr = 1;
+	args[0] = "rsync";
+	args[1] = transport->verbose ? "-av" : "-a";
+	args[2] = "--ignore-existing";
+	args[3] = "--exclude";
+	args[4] = "info";
+	args[5] = get_object_directory();;
+	args[6] = buf.buf;
+	args[7] = NULL;
+
+	if (run_command(&rsync))
+		return error("Could not push objects to %s", transport->url);
+
+	/* copy the refs to the temporary directory; they could be packed. */
+
+	temp_dir = mkdtemp(git_path("rsync-refs-XXXXXX"));
+	if (temp_dir == NULL)
+		die ("Could not make temporary directory");
+	temp_dir = strcpy(buffer, temp_dir);
+
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, temp_dir);
+	strbuf_addch(&buf, '/');
+
+	if (flags & TRANSPORT_PUSH_ALL) {
+		if (for_each_ref(write_one_ref, &buf))
+			return -1;
+	} else if (write_refs_to_temp_dir(&buf, refspec_nr, refspec))
+		return -1;
+
+	i = (flags & TRANSPORT_PUSH_FORCE) ? 2 : 3;
+	args[i++] = buf.buf;
+	args[i++] = transport->url;
+	args[i++] = NULL;
+	if (run_command(&rsync))
+		result = error("Could not push to %s", transport->url);
+
+	if (remove_dir_recursively(temp_dir, strlen(temp_dir), 0))
+		warning ("Could not remove temporary directory %s.", temp_dir);
+
+	return result;
+}
+
+static int disconnect_rsync(struct transport *transport)
+{
+	return 0;
+}
 
 /* Generic functions for using commit walkers */
 
@@ -402,7 +730,10 @@ struct transport *transport_get(struct remote *remote, const char *url)
 	ret->url = url;
 
 	if (!prefixcmp(url, "rsync://")) {
-		/* not supported; don't populate any ops */
+		ret->get_refs_list = get_refs_via_rsync;
+		ret->fetch = fetch_objs_via_rsync;
+		ret->push = rsync_transport_push;
+		ret->disconnect = disconnect_rsync;
 
 	} else if (!prefixcmp(url, "http://")
 	        || !prefixcmp(url, "https://")

dir.c, dir.h, refs.c

diff --git a/dir.c b/dir.c
index eb6c3ab..b18257e 100644
--- a/dir.c
+++ b/dir.c
@@ -685,3 +685,44 @@ int is_inside_dir(const char *dir)
 	char buffer[PATH_MAX];
 	return get_relative_cwd(buffer, sizeof(buffer), dir) != NULL;
 }
+
+int remove_dir_recursively(struct strbuf *path, int only_empty)
+{
+	DIR *dir = opendir(path->buf);
+	struct dirent *e;
+	int ret = 0, original_len = path->len, len;
+
+	if (!dir)
+		return -1;
+	if (path->buf[original_len - 1] != '/')
+		strbuf_addch(path, '/');
+
+	len = path->len;
+	while ((e = readdir(dir)) != NULL) {
+		struct stat st;
+		if ((e->d_name[0] == '.') &&
+		    ((e->d_name[1] == 0) ||
+		     ((e->d_name[1] == '.') && e->d_name[2] == 0)))
+			continue; /* "." and ".." */
+
+		strbuf_setlen(path, len);
+		strbuf_addstr(path, e->d_name);
+		if (lstat(path->buf, &st))
+			; /* fall thru */
+		else if (S_ISDIR(st.st_mode)) {
+			if (!remove_dir_recursively(path, only_empty))
+				continue; /* happy */
+		} else if (!only_empty && !unlink(path->buf))
+			continue; /* happy, too */
+
+		/* path too long, stat fails, or non-directory still exists */
+		ret = -1;
+		break;
+	}
+	closedir(dir);
+
+	strbuf_setlen(path, original_len);
+	if (!ret)
+		ret = rmdir(path->buf);
+	return ret;
+}
diff --git a/dir.h b/dir.h
index f55a87b..a248a23 100644
--- a/dir.h
+++ b/dir.h
@@ -64,4 +64,6 @@ extern struct dir_entry *dir_add_name(struct dir_struct *dir, const char *pathna
 extern char *get_relative_cwd(char *buffer, int size, const char *dir);
 extern int is_inside_dir(const char *dir);
 
+extern int remove_dir_recursively(struct strbuf *path, int only_empty);
+
 #endif
diff --git a/refs.c b/refs.c
index 07e260c..aff02cd 100644
--- a/refs.c
+++ b/refs.c
@@ -2,6 +2,7 @@
 #include "refs.h"
 #include "object.h"
 #include "tag.h"
+#include "dir.h"
 
 /* ISSYMREF=01 and ISPACKED=02 are public interfaces */
 #define REF_KNOWS_PEELED 04
@@ -671,57 +672,23 @@ static struct ref_lock *verify_lock(struct ref_lock *lock,
 	return lock;
 }
 
-static int remove_empty_dir_recursive(char *path, int len)
-{
-	DIR *dir = opendir(path);
-	struct dirent *e;
-	int ret = 0;
-
-	if (!dir)
-		return -1;
-	if (path[len-1] != '/')
-		path[len++] = '/';
-	while ((e = readdir(dir)) != NULL) {
-		struct stat st;
-		int namlen;
-		if ((e->d_name[0] == '.') &&
-		    ((e->d_name[1] == 0) ||
-		     ((e->d_name[1] == '.') && e->d_name[2] == 0)))
-			continue; /* "." and ".." */
-
-		namlen = strlen(e->d_name);
-		if ((len + namlen < PATH_MAX) &&
-		    strcpy(path + len, e->d_name) &&
-		    !lstat(path, &st) &&
-		    S_ISDIR(st.st_mode) &&
-		    !remove_empty_dir_recursive(path, len + namlen))
-			continue; /* happy */
-
-		/* path too long, stat fails, or non-directory still exists */
-		ret = -1;
-		break;
-	}
-	closedir(dir);
-	if (!ret) {
-		path[len] = 0;
-		ret = rmdir(path);
-	}
-	return ret;
-}
-
-static int remove_empty_directories(char *file)
+static int remove_empty_directories(const char *file)
 {
 	/* we want to create a file but there is a directory there;
 	 * if that is an empty directory (or a directory that contains
 	 * only empty directories), remove them.
 	 */
-	char path[PATH_MAX];
-	int len = strlen(file);
+	struct strbuf path;
+	int result;
 
-	if (len >= PATH_MAX) /* path too long ;-) */
-		return -1;
-	strcpy(path, file);
-	return remove_empty_dir_recursive(path, len);
+	strbuf_init(&path, 20);
+	strbuf_addstr(&path, file);
+
+	result = remove_dir_recursively(&path, 1);
+
+	strbuf_release(&path);
+
+	return result;
 }
 
 static int is_refname_available(const char *ref, const char *oldref,

t/t5510-fetch.sh, transport.c

diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 439430f..73a4e3c 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -153,4 +153,39 @@ test_expect_success 'bundle should be able to create a full history' '
 
 '
 
+test "$TEST_RSYNC" && {
+test_expect_success 'fetch via rsync' '
+	git pack-refs &&
+	mkdir rsynced &&
+	cd rsynced &&
+	git init &&
+	git fetch rsync://127.0.0.1$(pwd)/../.git master:refs/heads/master &&
+	git gc --prune &&
+	test $(git rev-parse master) = $(cd .. && git rev-parse master) &&
+	git fsck --full
+'
+
+test_expect_success 'push via rsync' '
+	mkdir ../rsynced2 &&
+	(cd ../rsynced2 &&
+	 git init) &&
+	git push rsync://127.0.0.1$(pwd)/../rsynced2/.git master &&
+	cd ../rsynced2 &&
+	git gc --prune &&
+	test $(git rev-parse master) = $(cd .. && git rev-parse master) &&
+	git fsck --full
+'
+
+test_expect_success 'push via rsync' '
+	cd .. &&
+	mkdir rsynced3 &&
+	(cd rsynced3 &&
+	 git init) &&
+	git push --all rsync://127.0.0.1$(pwd)/rsynced3/.git &&
+	cd rsynced3 &&
+	test $(git rev-parse master) = $(cd .. && git rev-parse master) &&
+	git fsck --full
+'
+}
+
 test_done
diff --git a/transport.c b/transport.c
index 4f9cddc..c8eed95 100644
--- a/transport.c
+++ b/transport.c
@@ -6,6 +6,330 @@
 #include "fetch-pack.h"
 #include "walker.h"
 #include "bundle.h"
+#include "dir.h"
+#include "refs.h"
+
+/* rsync support */
+
+/*
+ * We copy packed-refs and refs/ into a temporary file, then read the
+ * loose refs recursively (sorting whenever possible), and then inserting
+ * those packed refs that are not yet in the list (not validating, but
+ * assuming that the file is sorted).
+ *
+ * Appears refactoring this from refs.c is too cumbersome.
+ */
+
+static int direntry_cmp(const void *a, const void *b)
+{
+	const struct dirent *d1 = a;
+	const struct dirent *d2 = b;
+
+	return strcmp(d1->d_name, d2->d_name);
+}
+
+/*
+ * path is assumed to point to a buffer of PATH_MAX bytes, and
+ * path + name_offset is expected to point to "refs/".
+ */
+
+static int read_loose_refs(struct strbuf *path, int name_offset,
+		struct ref **tail)
+{
+	DIR *dir = opendir(path->buf);
+	struct dirent *de;
+	struct {
+		char **entries;
+		int nr, alloc;
+	} list;
+	int i, pathlen;
+
+	if (!dir)
+		return -1;
+
+	memset (&list, 0, sizeof(list));
+
+	while ((de = readdir(dir))) {
+		if (de->d_name[0] == '.' && (de->d_name[1] == '\0' ||
+				(de->d_name[1] == '.' &&
+				 de->d_name[2] == '\0')))
+			continue;
+		ALLOC_GROW(list.entries, list.nr + 1, list.alloc);
+		list.entries[list.nr++] = xstrdup(de->d_name);
+	}
+	closedir(dir);
+
+	/* sort the list */
+
+	qsort(list.entries, list.nr, sizeof(*de), direntry_cmp);
+
+	pathlen = path->len;
+	strbuf_addch(path, '/');
+
+	for (i = 0; i < list.nr; i++, strbuf_setlen(path, pathlen + 1)) {
+		strbuf_addstr(path, list.entries[i]);
+		if (read_loose_refs(path, name_offset, tail)) {
+			int fd = open(path->buf, O_RDONLY);
+			char buffer[40];
+			struct ref *next;
+
+			if (fd < 0)
+				continue;
+			next = alloc_ref(path->len - name_offset + 1);
+			if (read_in_full(fd, buffer, 40) != 40 ||
+					get_sha1_hex(buffer, next->old_sha1)) {
+				free(next);
+				continue;
+			}
+			close(fd);
+			strcpy(next->name, path->buf + name_offset);
+			(*tail)->next = next;
+			*tail = next;
+		}
+	}
+
+	for (i = 0; i < list.nr; i++)
+		free(list.entries[i]);
+	free(list.entries);
+
+	return 0;
+}
+
+/* insert the packed refs for which no loose refs were found */
+
+static void insert_packed_refs(const char *packed_refs, struct ref **list)
+{
+	FILE *f = fopen(packed_refs, "r");
+	static char buffer[PATH_MAX];
+
+	if (!f)
+		return;
+
+	for (;;) {
+		int cmp, len;
+
+		if (!fgets(buffer, sizeof(buffer), f)) {
+			fclose(f);
+			return;
+		}
+
+		if (hexval(buffer[0]) & 0x10)
+			continue;
+		len = strlen(buffer);
+		if (buffer[len - 1] == '\n')
+			buffer[--len] = '\0';
+		if (len < 41)
+			continue;
+		while ((*list)->next &&
+				(cmp = strcmp(buffer + 41,
+				      (*list)->next->name)) > 0)
+			list = &(*list)->next;
+		if (!(*list)->next || cmp < 0) {
+			struct ref *next = alloc_ref(len - 40);
+			buffer[40] = '\0';
+			if (get_sha1_hex(buffer, next->old_sha1)) {
+				warning ("invalid SHA-1: %s", buffer);
+				free(next);
+				continue;
+			}
+			strcpy(next->name, buffer + 41);
+			next->next = (*list)->next;
+			(*list)->next = next;
+			list = &(*list)->next;
+		}
+	}
+}
+
+static struct ref *get_refs_via_rsync(const struct transport *transport)
+{
+	struct strbuf buf = STRBUF_INIT, temp_dir = STRBUF_INIT;
+	struct ref dummy, *result = &dummy;
+	struct child_process rsync;
+	const char *args[5];
+	int temp_dir_len;
+
+	/* copy the refs to the temporary directory */
+
+	strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
+	if (!mkdtemp(temp_dir.buf))
+		die ("Could not make temporary directory");
+	temp_dir_len = temp_dir.len;
+
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addstr(&buf, "/refs");
+
+	memset(&rsync, 0, sizeof(rsync));
+	rsync.argv = args;
+	rsync.stdout_to_stderr = 1;
+	args[0] = "rsync";
+	args[1] = transport->verbose ? "-rv" : "-r";
+	args[2] = buf.buf;
+	args[3] = temp_dir.buf;
+	args[4] = NULL;
+
+	if (run_command(&rsync))
+		die ("Could not run rsync to get refs");
+
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addstr(&buf, "/packed-refs");
+
+	args[2] = buf.buf;
+
+	if (run_command(&rsync))
+		die ("Could not run rsync to get refs");
+
+	/* read the copied refs */
+
+	strbuf_addstr(&temp_dir, "/refs");
+	read_loose_refs(&temp_dir, temp_dir_len + 1, &result);
+	strbuf_setlen(&temp_dir, temp_dir_len);
+
+	result = &dummy;
+	strbuf_addstr(&temp_dir, "/packed-refs");
+	insert_packed_refs(temp_dir.buf, &result);
+	strbuf_setlen(&temp_dir, temp_dir_len);
+
+	if (remove_dir_recursively(&temp_dir, 0))
+		warning ("Error removing temporary directory %s.",
+				temp_dir.buf);
+
+	strbuf_release(&buf);
+	strbuf_release(&temp_dir);
+
+	return dummy.next;
+}
+
+static int fetch_objs_via_rsync(struct transport *transport,
+				 int nr_objs, struct ref **to_fetch)
+{
+	struct strbuf buf = STRBUF_INIT;
+	struct child_process rsync;
+	const char *args[8];
+	int result;
+
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addstr(&buf, "/objects/");
+
+	memset(&rsync, 0, sizeof(rsync));
+	rsync.argv = args;
+	rsync.stdout_to_stderr = 1;
+	args[0] = "rsync";
+	args[1] = transport->verbose ? "-rv" : "-r";
+	args[2] = "--ignore-existing";
+	args[3] = "--exclude";
+	args[4] = "info";
+	args[5] = buf.buf;
+	args[6] = get_object_directory();
+	args[7] = NULL;
+
+	/* NEEDSWORK: handle one level of alternates */
+	result = run_command(&rsync);
+
+	strbuf_release(&buf);
+
+	return result;
+}
+
+static int write_one_ref(const char *name, const unsigned char *sha1,
+		int flags, void *data)
+{
+	struct strbuf *buf = data;
+	int len = buf->len;
+	FILE *f;
+
+	if (flags && prefixcmp(name, "refs/heads/") &&
+			prefixcmp(name, "refs/tags/"))
+		return 0;
+
+	strbuf_addstr(buf, name);
+	if (safe_create_leading_directories(buf->buf) ||
+			!(f = fopen(buf->buf, "w")) ||
+			!fwrite(sha1_to_hex(sha1), 40, 1, f) ||
+			fputc('\n', f) == EOF ||
+			fclose(f))
+		return error("problems writing temporary file %s", buf->buf);
+	strbuf_setlen(buf, len);
+	return 0;
+}
+
+static int write_refs_to_temp_dir(struct strbuf *temp_dir,
+		int refspec_nr, const char **refspec)
+{
+	int i;
+
+	for (i = 0; i < refspec_nr; i++) {
+		unsigned char sha1[20];
+		char *ref;
+
+		if (dwim_ref(refspec[i], strlen(refspec[i]), sha1, &ref) != 1)
+			return error("Could not get ref %s", refspec[i]);
+
+		if (write_one_ref(ref, sha1, 0, temp_dir)) {
+			free(ref);
+			return -1;
+		}
+		free(ref);
+	}
+	return 0;
+}
+
+static int rsync_transport_push(struct transport *transport,
+		int refspec_nr, const char **refspec, int flags) {
+	struct strbuf buf = STRBUF_INIT, temp_dir = STRBUF_INIT;
+	int result = 0, i;
+	struct child_process rsync;
+	const char *args[8];
+
+	/* first push the objects */
+
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addch(&buf, '/');
+
+	memset(&rsync, 0, sizeof(rsync));
+	rsync.argv = args;
+	rsync.stdout_to_stderr = 1;
+	args[0] = "rsync";
+	args[1] = transport->verbose ? "-av" : "-a";
+	args[2] = "--ignore-existing";
+	args[3] = "--exclude";
+	args[4] = "info";
+	args[5] = get_object_directory();;
+	args[6] = buf.buf;
+	args[7] = NULL;
+
+	if (run_command(&rsync))
+		return error("Could not push objects to %s", transport->url);
+
+	/* copy the refs to the temporary directory; they could be packed. */
+
+	strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
+	if (!mkdtemp(temp_dir.buf))
+		die ("Could not make temporary directory");
+	strbuf_addch(&temp_dir, '/');
+
+	if (flags & TRANSPORT_PUSH_ALL) {
+		if (for_each_ref(write_one_ref, &temp_dir))
+			return -1;
+	} else if (write_refs_to_temp_dir(&temp_dir, refspec_nr, refspec))
+		return -1;
+
+	i = (flags & TRANSPORT_PUSH_FORCE) ? 2 : 3;
+	args[i++] = temp_dir.buf;
+	args[i++] = transport->url;
+	args[i++] = NULL;
+	if (run_command(&rsync))
+		result = error("Could not push to %s", transport->url);
+
+	if (remove_dir_recursively(&temp_dir, 0))
+		warning ("Could not remove temporary directory %s.",
+				temp_dir.buf);
+
+	strbuf_release(&buf);
+	strbuf_release(&temp_dir);
+
+	return result;
+}
 
 /* Generic functions for using commit walkers */
 
@@ -402,7 +726,9 @@ struct transport *transport_get(struct remote *remote, const char *url)
 	ret->url = url;
 
 	if (!prefixcmp(url, "rsync://")) {
-		/* not supported; don't populate any ops */
+		ret->get_refs_list = get_refs_via_rsync;
+		ret->fetch = fetch_objs_via_rsync;
+		ret->push = rsync_transport_push;
 
 	} else if (!prefixcmp(url, "http://")
 	        || !prefixcmp(url, "https://")

t/t5510-fetch.sh, transport.c

diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 439430f..73a4e3c 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -153,4 +153,39 @@ test_expect_success 'bundle should be able to create a full history' '
 
 '
 
+test "$TEST_RSYNC" && {
+test_expect_success 'fetch via rsync' '
+	git pack-refs &&
+	mkdir rsynced &&
+	cd rsynced &&
+	git init &&
+	git fetch rsync://127.0.0.1$(pwd)/../.git master:refs/heads/master &&
+	git gc --prune &&
+	test $(git rev-parse master) = $(cd .. && git rev-parse master) &&
+	git fsck --full
+'
+
+test_expect_success 'push via rsync' '
+	mkdir ../rsynced2 &&
+	(cd ../rsynced2 &&
+	 git init) &&
+	git push rsync://127.0.0.1$(pwd)/../rsynced2/.git master &&
+	cd ../rsynced2 &&
+	git gc --prune &&
+	test $(git rev-parse master) = $(cd .. && git rev-parse master) &&
+	git fsck --full
+'
+
+test_expect_success 'push via rsync' '
+	cd .. &&
+	mkdir rsynced3 &&
+	(cd rsynced3 &&
+	 git init) &&
+	git push --all rsync://127.0.0.1$(pwd)/rsynced3/.git &&
+	cd rsynced3 &&
+	test $(git rev-parse master) = $(cd .. && git rev-parse master) &&
+	git fsck --full
+'
+}
+
 test_done
diff --git a/transport.c b/transport.c
index 4f9cddc..a2ee8f3 100644
--- a/transport.c
+++ b/transport.c
@@ -6,6 +6,330 @@
 #include "fetch-pack.h"
 #include "walker.h"
 #include "bundle.h"
+#include "dir.h"
+#include "refs.h"
+
+/* rsync support */
+
+/*
+ * We copy packed-refs and refs/ into a temporary file, then read the
+ * loose refs recursively (sorting whenever possible), and then inserting
+ * those packed refs that are not yet in the list (not validating, but
+ * assuming that the file is sorted).
+ *
+ * Appears refactoring this from refs.c is too cumbersome.
+ */
+
+static int str_cmp(const void *a, const void *b)
+{
+	const char *s1 = a;
+	const char *s2 = b;
+
+	return strcmp(s1, s2);
+}
+
+/* path->buf + name_offset is expected to point to "refs/" */
+
+static int read_loose_refs(struct strbuf *path, int name_offset,
+		struct ref **tail)
+{
+	DIR *dir = opendir(path->buf);
+	struct dirent *de;
+	struct {
+		char **entries;
+		int nr, alloc;
+	} list;
+	int i, pathlen;
+
+	if (!dir)
+		return -1;
+
+	memset (&list, 0, sizeof(list));
+
+	while ((de = readdir(dir))) {
+		if (de->d_name[0] == '.' && (de->d_name[1] == '\0' ||
+				(de->d_name[1] == '.' &&
+				 de->d_name[2] == '\0')))
+			continue;
+		ALLOC_GROW(list.entries, list.nr + 1, list.alloc);
+		list.entries[list.nr++] = xstrdup(de->d_name);
+	}
+	closedir(dir);
+
+	/* sort the list */
+
+	qsort(list.entries, list.nr, sizeof(char *), str_cmp);
+
+	pathlen = path->len;
+	strbuf_addch(path, '/');
+
+	for (i = 0; i < list.nr; i++, strbuf_setlen(path, pathlen + 1)) {
+		strbuf_addstr(path, list.entries[i]);
+		if (read_loose_refs(path, name_offset, tail)) {
+			int fd = open(path->buf, O_RDONLY);
+			char buffer[40];
+			struct ref *next;
+
+			if (fd < 0)
+				continue;
+			next = alloc_ref(path->len - name_offset + 1);
+			if (read_in_full(fd, buffer, 40) != 40 ||
+					get_sha1_hex(buffer, next->old_sha1)) {
+				close(fd);
+				free(next);
+				continue;
+			}
+			close(fd);
+			strcpy(next->name, path->buf + name_offset);
+			(*tail)->next = next;
+			*tail = next;
+		}
+	}
+	strbuf_setlen(path, pathlen);
+
+	for (i = 0; i < list.nr; i++)
+		free(list.entries[i]);
+	free(list.entries);
+
+	return 0;
+}
+
+/* insert the packed refs for which no loose refs were found */
+
+static void insert_packed_refs(const char *packed_refs, struct ref **list)
+{
+	FILE *f = fopen(packed_refs, "r");
+	static char buffer[PATH_MAX];
+
+	if (!f)
+		return;
+
+	for (;;) {
+		int cmp, len;
+
+		if (!fgets(buffer, sizeof(buffer), f)) {
+			fclose(f);
+			return;
+		}
+
+		if (hexval(buffer[0]) > 0xf)
+			continue;
+		len = strlen(buffer);
+		if (buffer[len - 1] == '\n')
+			buffer[--len] = '\0';
+		if (len < 41)
+			continue;
+		while ((*list)->next &&
+				(cmp = strcmp(buffer + 41,
+				      (*list)->next->name)) > 0)
+			list = &(*list)->next;
+		if (!(*list)->next || cmp < 0) {
+			struct ref *next = alloc_ref(len - 40);
+			buffer[40] = '\0';
+			if (get_sha1_hex(buffer, next->old_sha1)) {
+				warning ("invalid SHA-1: %s", buffer);
+				free(next);
+				continue;
+			}
+			strcpy(next->name, buffer + 41);
+			next->next = (*list)->next;
+			(*list)->next = next;
+			list = &(*list)->next;
+		}
+	}
+}
+
+static struct ref *get_refs_via_rsync(const struct transport *transport)
+{
+	struct strbuf buf = STRBUF_INIT, temp_dir = STRBUF_INIT;
+	struct ref dummy, *tail = &dummy;
+	struct child_process rsync;
+	const char *args[5];
+	int temp_dir_len;
+
+	/* copy the refs to the temporary directory */
+
+	strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
+	if (!mkdtemp(temp_dir.buf))
+		die ("Could not make temporary directory");
+	temp_dir_len = temp_dir.len;
+
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addstr(&buf, "/refs");
+
+	memset(&rsync, 0, sizeof(rsync));
+	rsync.argv = args;
+	rsync.stdout_to_stderr = 1;
+	args[0] = "rsync";
+	args[1] = transport->verbose ? "-rv" : "-r";
+	args[2] = buf.buf;
+	args[3] = temp_dir.buf;
+	args[4] = NULL;
+
+	if (run_command(&rsync))
+		die ("Could not run rsync to get refs");
+
+	strbuf_reset(&buf);
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addstr(&buf, "/packed-refs");
+
+	args[2] = buf.buf;
+
+	if (run_command(&rsync))
+		die ("Could not run rsync to get refs");
+
+	/* read the copied refs */
+
+	strbuf_addstr(&temp_dir, "/refs");
+	read_loose_refs(&temp_dir, temp_dir_len + 1, &tail);
+	strbuf_setlen(&temp_dir, temp_dir_len);
+
+	tail = &dummy;
+	strbuf_addstr(&temp_dir, "/packed-refs");
+	insert_packed_refs(temp_dir.buf, &tail);
+	strbuf_setlen(&temp_dir, temp_dir_len);
+
+	if (remove_dir_recursively(&temp_dir, 0))
+		warning ("Error removing temporary directory %s.",
+				temp_dir.buf);
+
+	strbuf_release(&buf);
+	strbuf_release(&temp_dir);
+
+	return dummy.next;
+}
+
+static int fetch_objs_via_rsync(struct transport *transport,
+				 int nr_objs, struct ref **to_fetch)
+{
+	struct strbuf buf = STRBUF_INIT;
+	struct child_process rsync;
+	const char *args[8];
+	int result;
+
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addstr(&buf, "/objects/");
+
+	memset(&rsync, 0, sizeof(rsync));
+	rsync.argv = args;
+	rsync.stdout_to_stderr = 1;
+	args[0] = "rsync";
+	args[1] = transport->verbose ? "-rv" : "-r";
+	args[2] = "--ignore-existing";
+	args[3] = "--exclude";
+	args[4] = "info";
+	args[5] = buf.buf;
+	args[6] = get_object_directory();
+	args[7] = NULL;
+
+	/* NEEDSWORK: handle one level of alternates */
+	result = run_command(&rsync);
+
+	strbuf_release(&buf);
+
+	return result;
+}
+
+static int write_one_ref(const char *name, const unsigned char *sha1,
+		int flags, void *data)
+{
+	struct strbuf *buf = data;
+	int len = buf->len;
+	FILE *f;
+
+	/* when called via for_each_ref(), flags is non-zero */
+	if (flags && prefixcmp(name, "refs/heads/") &&
+			prefixcmp(name, "refs/tags/"))
+		return 0;
+
+	strbuf_addstr(buf, name);
+	if (safe_create_leading_directories(buf->buf) ||
+			!(f = fopen(buf->buf, "w")) ||
+			fprintf(f, "%s\n", sha1_to_hex(sha1)) < 0 ||
+			fclose(f))
+		return error("problems writing temporary file %s", buf->buf);
+	strbuf_setlen(buf, len);
+	return 0;
+}
+
+static int write_refs_to_temp_dir(struct strbuf *temp_dir,
+		int refspec_nr, const char **refspec)
+{
+	int i;
+
+	for (i = 0; i < refspec_nr; i++) {
+		unsigned char sha1[20];
+		char *ref;
+
+		if (dwim_ref(refspec[i], strlen(refspec[i]), sha1, &ref) != 1)
+			return error("Could not get ref %s", refspec[i]);
+
+		if (write_one_ref(ref, sha1, 0, temp_dir)) {
+			free(ref);
+			return -1;
+		}
+		free(ref);
+	}
+	return 0;
+}
+
+static int rsync_transport_push(struct transport *transport,
+		int refspec_nr, const char **refspec, int flags)
+{
+	struct strbuf buf = STRBUF_INIT, temp_dir = STRBUF_INIT;
+	int result = 0, i;
+	struct child_process rsync;
+	const char *args[8];
+
+	/* first push the objects */
+
+	strbuf_addstr(&buf, transport->url);
+	strbuf_addch(&buf, '/');
+
+	memset(&rsync, 0, sizeof(rsync));
+	rsync.argv = args;
+	rsync.stdout_to_stderr = 1;
+	args[0] = "rsync";
+	args[1] = transport->verbose ? "-av" : "-a";
+	args[2] = "--ignore-existing";
+	args[3] = "--exclude";
+	args[4] = "info";
+	args[5] = get_object_directory();;
+	args[6] = buf.buf;
+	args[7] = NULL;
+
+	if (run_command(&rsync))
+		return error("Could not push objects to %s", transport->url);
+
+	/* copy the refs to the temporary directory; they could be packed. */
+
+	strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
+	if (!mkdtemp(temp_dir.buf))
+		die ("Could not make temporary directory");
+	strbuf_addch(&temp_dir, '/');
+
+	if (flags & TRANSPORT_PUSH_ALL) {
+		if (for_each_ref(write_one_ref, &temp_dir))
+			return -1;
+	} else if (write_refs_to_temp_dir(&temp_dir, refspec_nr, refspec))
+		return -1;
+
+	i = (flags & TRANSPORT_PUSH_FORCE) ? 2 : 3;
+	args[i++] = temp_dir.buf;
+	args[i++] = transport->url;
+	args[i++] = NULL;
+	if (run_command(&rsync))
+		result = error("Could not push to %s", transport->url);
+
+	if (remove_dir_recursively(&temp_dir, 0))
+		warning ("Could not remove temporary directory %s.",
+				temp_dir.buf);
+
+	strbuf_release(&buf);
+	strbuf_release(&temp_dir);
+
+	return result;
+}
 
 /* Generic functions for using commit walkers */
 
@@ -402,7 +726,9 @@ struct transport *transport_get(struct remote *remote, const char *url)
 	ret->url = url;
 
 	if (!prefixcmp(url, "rsync://")) {
-		/* not supported; don't populate any ops */
+		ret->get_refs_list = get_refs_via_rsync;
+		ret->fetch = fetch_objs_via_rsync;
+		ret->push = rsync_transport_push;
 
 	} else if (!prefixcmp(url, "http://")
 	        || !prefixcmp(url, "https://")