git

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#include "builtin.h"
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#include "transport.h"
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#include "run-command.h"
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#include "pkt-line.h"
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static const char usage_msg[] =
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	"git remote-ext <remote> <url>";
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/*
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 * URL syntax:
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 *	'command [arg1 [arg2 [...]]]'	Invoke command with given arguments.
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 *	Special characters:
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 *	'% ': Literal space in argument.
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 *	'%%': Literal percent sign.
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 *	'%S': Name of service (git-upload-pack/git-upload-archive/
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 *		git-receive-pack.
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 *	'%s': Same as \s, but with possible git- prefix stripped.
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 *	'%G': Only allowed as first 'character' of argument. Do not pass this
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 *		Argument to command, instead send this as name of repository
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 *		in in-line git://-style request (also activates sending this
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 *		style of request).
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 *	'%V': Only allowed as first 'character' of argument. Used in
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 *		conjunction with '%G': Do not pass this argument to command,
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 *		instead send this as vhost in git://-style request (note: does
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 *		not activate sending git:// style request).
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 */
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static char *git_req;
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static char *git_req_vhost;
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static char *strip_escapes(const char *str, const char *service,
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	const char **next)
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{
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	size_t rpos = 0;
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	int escape = 0;
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	char special = 0;
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	const char *service_noprefix = service;
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	struct strbuf ret = STRBUF_INIT;
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	skip_prefix(service_noprefix, "git-", &service_noprefix);
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	/* Pass the service to command. */
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	setenv("GIT_EXT_SERVICE", service, 1);
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	setenv("GIT_EXT_SERVICE_NOPREFIX", service_noprefix, 1);
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	/* Scan the length of argument. */
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	while (str[rpos] && (escape || str[rpos] != ' ')) {
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		if (escape) {
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			switch (str[rpos]) {
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			case ' ':
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			case '%':
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			case 's':
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			case 'S':
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				break;
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			case 'G':
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			case 'V':
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				special = str[rpos];
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				if (rpos == 1)
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					break;
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				/* fallthrough */
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			default:
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				die("Bad remote-ext placeholder '%%%c'.",
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					str[rpos]);
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			}
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			escape = 0;
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		} else
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			escape = (str[rpos] == '%');
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		rpos++;
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	}
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	if (escape && !str[rpos])
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		die("remote-ext command has incomplete placeholder");
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	*next = str + rpos;
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	if (**next == ' ')
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		++*next;	/* Skip over space */
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	/*
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	 * Do the actual placeholder substitution. The string will be short
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	 * enough not to overflow integers.
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	 */
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	rpos = special ? 2 : 0;		/* Skip first 2 bytes in specials. */
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	escape = 0;
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	while (str[rpos] && (escape || str[rpos] != ' ')) {
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		if (escape) {
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			switch (str[rpos]) {
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			case ' ':
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			case '%':
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				strbuf_addch(&ret, str[rpos]);
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				break;
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			case 's':
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				strbuf_addstr(&ret, service_noprefix);
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				break;
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			case 'S':
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				strbuf_addstr(&ret, service);
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				break;
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			}
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			escape = 0;
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		} else
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			switch (str[rpos]) {
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			case '%':
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				escape = 1;
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				break;
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			default:
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				strbuf_addch(&ret, str[rpos]);
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				break;
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			}
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		rpos++;
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	}
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	switch (special) {
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	case 'G':
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		git_req = strbuf_detach(&ret, NULL);
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		return NULL;
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	case 'V':
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		git_req_vhost = strbuf_detach(&ret, NULL);
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		return NULL;
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	default:
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		return strbuf_detach(&ret, NULL);
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	}
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}
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static void parse_argv(struct strvec *out, const char *arg, const char *service)
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{
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	while (*arg) {
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		char *expanded = strip_escapes(arg, service, &arg);
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		if (expanded)
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			strvec_push(out, expanded);
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		free(expanded);
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	}
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}
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static void send_git_request(int stdin_fd, const char *serv, const char *repo,
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	const char *vhost)
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{
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	if (!vhost)
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		packet_write_fmt(stdin_fd, "%s %s%c", serv, repo, 0);
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	else
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		packet_write_fmt(stdin_fd, "%s %s%chost=%s%c", serv, repo, 0,
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			     vhost, 0);
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}
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static int run_child(const char *arg, const char *service)
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{
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	int r;
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	struct child_process child = CHILD_PROCESS_INIT;
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	child.in = -1;
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	child.out = -1;
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	child.err = 0;
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	parse_argv(&child.args, arg, service);
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	if (start_command(&child) < 0)
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		die("Can't run specified command");
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	if (git_req)
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		send_git_request(child.in, service, git_req, git_req_vhost);
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	r = bidirectional_transfer_loop(child.out, child.in);
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	if (!r)
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		r = finish_command(&child);
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	else
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		finish_command(&child);
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	return r;
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}
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#define MAXCOMMAND 4096
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static int command_loop(const char *child)
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{
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	char buffer[MAXCOMMAND];
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	while (1) {
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		size_t i;
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		const char *arg;
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		if (!fgets(buffer, MAXCOMMAND - 1, stdin)) {
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			if (ferror(stdin))
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				die("Command input error");
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			exit(0);
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		}
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		/* Strip end of line characters. */
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		i = strlen(buffer);
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		while (i > 0 && isspace(buffer[i - 1]))
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			buffer[--i] = 0;
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		if (!strcmp(buffer, "capabilities")) {
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			printf("*connect\n\n");
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			fflush(stdout);
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		} else if (skip_prefix(buffer, "connect ", &arg)) {
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			printf("\n");
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			fflush(stdout);
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			return run_child(child, arg);
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		} else {
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			fprintf(stderr, "Bad command");
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			return 1;
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		}
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	}
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}
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int cmd_remote_ext(int argc, const char **argv, const char *prefix)
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{
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	BUG_ON_NON_EMPTY_PREFIX(prefix);
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	if (argc != 3)
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		usage(usage_msg);
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	return command_loop(argv[2]);
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}
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