receive-pack: make it a builtin

It is a good thing to do in general, but more importantly, transport
routines can only be used by built-ins, which is what I'll be adding next.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 520 insertions, 0 deletions

diff --git a/builtin-receive-pack.c b/builtin-receive-pack.c
new file mode 100644
index 0000000000..6d6027ead1
--- /dev/null
+++ b/builtin-receive-pack.c
@@ -0,0 +1,520 @@
+#include "cache.h"
+#include "pack.h"
+#include "refs.h"
+#include "pkt-line.h"
+#include "run-command.h"
+#include "exec_cmd.h"
+#include "commit.h"
+#include "object.h"
+
+static const char receive_pack_usage[] = "git-receive-pack <git-dir>";
+
+static int deny_non_fast_forwards = 0;
+static int receive_fsck_objects;
+static int receive_unpack_limit = -1;
+static int transfer_unpack_limit = -1;
+static int unpack_limit = 100;
+static int report_status;
+
+static char capabilities[] = " report-status delete-refs ";
+static int capabilities_sent;
+
+static int receive_pack_config(const char *var, const char *value, void *cb)
+{
+	if (strcmp(var, "receive.denynonfastforwards") == 0) {
+		deny_non_fast_forwards = git_config_bool(var, value);
+		return 0;
+	}
+
+	if (strcmp(var, "receive.unpacklimit") == 0) {
+		receive_unpack_limit = git_config_int(var, value);
+		return 0;
+	}
+
+	if (strcmp(var, "transfer.unpacklimit") == 0) {
+		transfer_unpack_limit = git_config_int(var, value);
+		return 0;
+	}
+
+	if (strcmp(var, "receive.fsckobjects") == 0) {
+		receive_fsck_objects = git_config_bool(var, value);
+		return 0;
+	}
+
+	return git_default_config(var, value, cb);
+}
+
+static int show_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
+{
+	if (capabilities_sent)
+		packet_write(1, "%s %s\n", sha1_to_hex(sha1), path);
+	else
+		packet_write(1, "%s %s%c%s\n",
+			     sha1_to_hex(sha1), path, 0, capabilities);
+	capabilities_sent = 1;
+	return 0;
+}
+
+static void write_head_info(void)
+{
+	for_each_ref(show_ref, NULL);
+	if (!capabilities_sent)
+		show_ref("capabilities^{}", null_sha1, 0, NULL);
+
+}
+
+struct command {
+	struct command *next;
+	const char *error_string;
+	unsigned char old_sha1[20];
+	unsigned char new_sha1[20];
+	char ref_name[FLEX_ARRAY]; /* more */
+};
+
+static struct command *commands;
+
+static const char pre_receive_hook[] = "hooks/pre-receive";
+static const char post_receive_hook[] = "hooks/post-receive";
+
+static int hook_status(int code, const char *hook_name)
+{
+	switch (code) {
+	case 0:
+		return 0;
+	case -ERR_RUN_COMMAND_FORK:
+		return error("hook fork failed");
+	case -ERR_RUN_COMMAND_EXEC:
+		return error("hook execute failed");
+	case -ERR_RUN_COMMAND_PIPE:
+		return error("hook pipe failed");
+	case -ERR_RUN_COMMAND_WAITPID:
+		return error("waitpid failed");
+	case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
+		return error("waitpid is confused");
+	case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
+		return error("%s died of signal", hook_name);
+	case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
+		return error("%s died strangely", hook_name);
+	default:
+		error("%s exited with error code %d", hook_name, -code);
+		return -code;
+	}
+}
+
+static int run_hook(const char *hook_name)
+{
+	static char buf[sizeof(commands->old_sha1) * 2 + PATH_MAX + 4];
+	struct command *cmd;
+	struct child_process proc;
+	const char *argv[2];
+	int have_input = 0, code;
+
+	for (cmd = commands; !have_input && cmd; cmd = cmd->next) {
+		if (!cmd->error_string)
+			have_input = 1;
+	}
+
+	if (!have_input || access(hook_name, X_OK) < 0)
+		return 0;
+
+	argv[0] = hook_name;
+	argv[1] = NULL;
+
+	memset(&proc, 0, sizeof(proc));
+	proc.argv = argv;
+	proc.in = -1;
+	proc.stdout_to_stderr = 1;
+
+	code = start_command(&proc);
+	if (code)
+		return hook_status(code, hook_name);
+	for (cmd = commands; cmd; cmd = cmd->next) {
+		if (!cmd->error_string) {
+			size_t n = snprintf(buf, sizeof(buf), "%s %s %s\n",
+				sha1_to_hex(cmd->old_sha1),
+				sha1_to_hex(cmd->new_sha1),
+				cmd->ref_name);
+			if (write_in_full(proc.in, buf, n) != n)
+				break;
+		}
+	}
+	close(proc.in);
+	return hook_status(finish_command(&proc), hook_name);
+}
+
+static int run_update_hook(struct command *cmd)
+{
+	static const char update_hook[] = "hooks/update";
+	struct child_process proc;
+	const char *argv[5];
+
+	if (access(update_hook, X_OK) < 0)
+		return 0;
+
+	argv[0] = update_hook;
+	argv[1] = cmd->ref_name;
+	argv[2] = sha1_to_hex(cmd->old_sha1);
+	argv[3] = sha1_to_hex(cmd->new_sha1);
+	argv[4] = NULL;
+
+	memset(&proc, 0, sizeof(proc));
+	proc.argv = argv;
+	proc.no_stdin = 1;
+	proc.stdout_to_stderr = 1;
+
+	return hook_status(run_command(&proc), update_hook);
+}
+
+static const char *update(struct command *cmd)
+{
+	const char *name = cmd->ref_name;
+	unsigned char *old_sha1 = cmd->old_sha1;
+	unsigned char *new_sha1 = cmd->new_sha1;
+	struct ref_lock *lock;
+
+	/* only refs/... are allowed */
+	if (prefixcmp(name, "refs/") || check_ref_format(name + 5)) {
+		error("refusing to create funny ref '%s' remotely", name);
+		return "funny refname";
+	}
+
+	if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
+		error("unpack should have generated %s, "
+		      "but I can't find it!", sha1_to_hex(new_sha1));
+		return "bad pack";
+	}
+	if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
+	    !is_null_sha1(old_sha1) &&
+	    !prefixcmp(name, "refs/heads/")) {
+		struct object *old_object, *new_object;
+		struct commit *old_commit, *new_commit;
+		struct commit_list *bases, *ent;
+
+		old_object = parse_object(old_sha1);
+		new_object = parse_object(new_sha1);
+
+		if (!old_object || !new_object ||
+		    old_object->type != OBJ_COMMIT ||
+		    new_object->type != OBJ_COMMIT) {
+			error("bad sha1 objects for %s", name);
+			return "bad ref";
+		}
+		old_commit = (struct commit *)old_object;
+		new_commit = (struct commit *)new_object;
+		bases = get_merge_bases(old_commit, new_commit, 1);
+		for (ent = bases; ent; ent = ent->next)
+			if (!hashcmp(old_sha1, ent->item->object.sha1))
+				break;
+		free_commit_list(bases);
+		if (!ent) {
+			error("denying non-fast forward %s"
+			      " (you should pull first)", name);
+			return "non-fast forward";
+		}
+	}
+	if (run_update_hook(cmd)) {
+		error("hook declined to update %s", name);
+		return "hook declined";
+	}
+
+	if (is_null_sha1(new_sha1)) {
+		if (!parse_object(old_sha1)) {
+			warning ("Allowing deletion of corrupt ref.");
+			old_sha1 = NULL;
+		}
+		if (delete_ref(name, old_sha1)) {
+			error("failed to delete %s", name);
+			return "failed to delete";
+		}
+		return NULL; /* good */
+	}
+	else {
+		lock = lock_any_ref_for_update(name, old_sha1, 0);
+		if (!lock) {
+			error("failed to lock %s", name);
+			return "failed to lock";
+		}
+		if (write_ref_sha1(lock, new_sha1, "push")) {
+			return "failed to write"; /* error() already called */
+		}
+		return NULL; /* good */
+	}
+}
+
+static char update_post_hook[] = "hooks/post-update";
+
+static void run_update_post_hook(struct command *cmd)
+{
+	struct command *cmd_p;
+	int argc;
+	const char **argv;
+
+	for (argc = 0, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
+		if (cmd_p->error_string)
+			continue;
+		argc++;
+	}
+	if (!argc || access(update_post_hook, X_OK) < 0)
+		return;
+	argv = xmalloc(sizeof(*argv) * (2 + argc));
+	argv[0] = update_post_hook;
+
+	for (argc = 1, cmd_p = cmd; cmd_p; cmd_p = cmd_p->next) {
+		char *p;
+		if (cmd_p->error_string)
+			continue;
+		p = xmalloc(strlen(cmd_p->ref_name) + 1);
+		strcpy(p, cmd_p->ref_name);
+		argv[argc] = p;
+		argc++;
+	}
+	argv[argc] = NULL;
+	run_command_v_opt(argv, RUN_COMMAND_NO_STDIN
+		| RUN_COMMAND_STDOUT_TO_STDERR);
+}
+
+static void execute_commands(const char *unpacker_error)
+{
+	struct command *cmd = commands;
+
+	if (unpacker_error) {
+		while (cmd) {
+			cmd->error_string = "n/a (unpacker error)";
+			cmd = cmd->next;
+		}
+		return;
+	}
+
+	if (run_hook(pre_receive_hook)) {
+		while (cmd) {
+			cmd->error_string = "pre-receive hook declined";
+			cmd = cmd->next;
+		}
+		return;
+	}
+
+	while (cmd) {
+		cmd->error_string = update(cmd);
+		cmd = cmd->next;
+	}
+}
+
+static void read_head_info(void)
+{
+	struct command **p = &commands;
+	for (;;) {
+		static char line[1000];
+		unsigned char old_sha1[20], new_sha1[20];
+		struct command *cmd;
+		char *refname;
+		int len, reflen;
+
+		len = packet_read_line(0, line, sizeof(line));
+		if (!len)
+			break;
+		if (line[len-1] == '\n')
+			line[--len] = 0;
+		if (len < 83 ||
+		    line[40] != ' ' ||
+		    line[81] != ' ' ||
+		    get_sha1_hex(line, old_sha1) ||
+		    get_sha1_hex(line + 41, new_sha1))
+			die("protocol error: expected old/new/ref, got '%s'",
+			    line);
+
+		refname = line + 82;
+		reflen = strlen(refname);
+		if (reflen + 82 < len) {
+			if (strstr(refname + reflen + 1, "report-status"))
+				report_status = 1;
+		}
+		cmd = xmalloc(sizeof(struct command) + len - 80);
+		hashcpy(cmd->old_sha1, old_sha1);
+		hashcpy(cmd->new_sha1, new_sha1);
+		memcpy(cmd->ref_name, line + 82, len - 81);
+		cmd->error_string = NULL;
+		cmd->next = NULL;
+		*p = cmd;
+		p = &cmd->next;
+	}
+}
+
+static const char *parse_pack_header(struct pack_header *hdr)
+{
+	switch (read_pack_header(0, hdr)) {
+	case PH_ERROR_EOF:
+		return "eof before pack header was fully read";
+
+	case PH_ERROR_PACK_SIGNATURE:
+		return "protocol error (pack signature mismatch detected)";
+
+	case PH_ERROR_PROTOCOL:
+		return "protocol error (pack version unsupported)";
+
+	default:
+		return "unknown error in parse_pack_header";
+
+	case 0:
+		return NULL;
+	}
+}
+
+static const char *pack_lockfile;
+
+static const char *unpack(void)
+{
+	struct pack_header hdr;
+	const char *hdr_err;
+	char hdr_arg[38];
+
+	hdr_err = parse_pack_header(&hdr);
+	if (hdr_err)
+		return hdr_err;
+	snprintf(hdr_arg, sizeof(hdr_arg),
+			"--pack_header=%"PRIu32",%"PRIu32,
+			ntohl(hdr.hdr_version), ntohl(hdr.hdr_entries));
+
+	if (ntohl(hdr.hdr_entries) < unpack_limit) {
+		int code, i = 0;
+		const char *unpacker[4];
+		unpacker[i++] = "unpack-objects";
+		if (receive_fsck_objects)
+			unpacker[i++] = "--strict";
+		unpacker[i++] = hdr_arg;
+		unpacker[i++] = NULL;
+		code = run_command_v_opt(unpacker, RUN_GIT_CMD);
+		switch (code) {
+		case 0:
+			return NULL;
+		case -ERR_RUN_COMMAND_FORK:
+			return "unpack fork failed";
+		case -ERR_RUN_COMMAND_EXEC:
+			return "unpack execute failed";
+		case -ERR_RUN_COMMAND_WAITPID:
+			return "waitpid failed";
+		case -ERR_RUN_COMMAND_WAITPID_WRONG_PID:
+			return "waitpid is confused";
+		case -ERR_RUN_COMMAND_WAITPID_SIGNAL:
+			return "unpacker died of signal";
+		case -ERR_RUN_COMMAND_WAITPID_NOEXIT:
+			return "unpacker died strangely";
+		default:
+			return "unpacker exited with error code";
+		}
+	} else {
+		const char *keeper[7];
+		int s, status, i = 0;
+		char keep_arg[256];
+		struct child_process ip;
+
+		s = sprintf(keep_arg, "--keep=receive-pack %"PRIuMAX" on ", (uintmax_t) getpid());
+		if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
+			strcpy(keep_arg + s, "localhost");
+
+		keeper[i++] = "index-pack";
+		keeper[i++] = "--stdin";
+		if (receive_fsck_objects)
+			keeper[i++] = "--strict";
+		keeper[i++] = "--fix-thin";
+		keeper[i++] = hdr_arg;
+		keeper[i++] = keep_arg;
+		keeper[i++] = NULL;
+		memset(&ip, 0, sizeof(ip));
+		ip.argv = keeper;
+		ip.out = -1;
+		ip.git_cmd = 1;
+		if (start_command(&ip))
+			return "index-pack fork failed";
+		pack_lockfile = index_pack_lockfile(ip.out);
+		close(ip.out);
+		status = finish_command(&ip);
+		if (!status) {
+			reprepare_packed_git();
+			return NULL;
+		}
+		return "index-pack abnormal exit";
+	}
+}
+
+static void report(const char *unpack_status)
+{
+	struct command *cmd;
+	packet_write(1, "unpack %s\n",
+		     unpack_status ? unpack_status : "ok");
+	for (cmd = commands; cmd; cmd = cmd->next) {
+		if (!cmd->error_string)
+			packet_write(1, "ok %s\n",
+				     cmd->ref_name);
+		else
+			packet_write(1, "ng %s %s\n",
+				     cmd->ref_name, cmd->error_string);
+	}
+	packet_flush(1);
+}
+
+static int delete_only(struct command *cmd)
+{
+	while (cmd) {
+		if (!is_null_sha1(cmd->new_sha1))
+			return 0;
+		cmd = cmd->next;
+	}
+	return 1;
+}
+
+int cmd_receive_pack(int argc, const char **argv, const char *prefix)
+{
+	int i;
+	char *dir = NULL;
+
+	argv++;
+	for (i = 1; i < argc; i++) {
+		const char *arg = *argv++;
+
+		if (*arg == '-') {
+			/* Do flag handling here */
+			usage(receive_pack_usage);
+		}
+		if (dir)
+			usage(receive_pack_usage);
+		dir = xstrdup(arg);
+	}
+	if (!dir)
+		usage(receive_pack_usage);
+
+	setup_path();
+
+	if (!enter_repo(dir, 0))
+		die("'%s': unable to chdir or not a git archive", dir);
+
+	if (is_repository_shallow())
+		die("attempt to push into a shallow repository");
+
+	git_config(receive_pack_config, NULL);
+
+	if (0 <= transfer_unpack_limit)
+		unpack_limit = transfer_unpack_limit;
+	else if (0 <= receive_unpack_limit)
+		unpack_limit = receive_unpack_limit;
+
+	write_head_info();
+
+	/* EOF */
+	packet_flush(1);
+
+	read_head_info();
+	if (commands) {
+		const char *unpack_status = NULL;
+
+		if (!delete_only(commands))
+			unpack_status = unpack();
+		execute_commands(unpack_status);
+		if (pack_lockfile)
+			unlink(pack_lockfile);
+		if (report_status)
+			report(unpack_status);
+		run_hook(post_receive_hook);
+		run_update_post_hook(commands);
+	}
+	return 0;
+}