comparison contrib/chg/chg.c @ 30620:937c52f06709

chg: start server at a unique address

See the previous patch for motivation. Previously, the server is started at
a globally shared address. This patch appends pid to the address so it
becomes unique.

Note: with Linux pid namespace, the address may be non-unique, but it does
not affect correctness of chg - chg client will receive an redirection and
that's it.

30619:88efb4fb1975

#define UNIX_PATH_MAX (sizeof(((struct sockaddr_un *)NULL)->sun_path))
#endif

struct cmdserveropts {
	char sockname[UNIX_PATH_MAX];
	char redirectsockname[UNIX_PATH_MAX];
	char lockfile[UNIX_PATH_MAX];
	size_t argsize;
	const char **args;
	int lockfd;

	if (r < 0 || (size_t)r >= sizeof(opts->sockname))
		abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
	r = snprintf(opts->lockfile, sizeof(opts->lockfile), lockfmt, basename);
	if (r < 0 || (size_t)r >= sizeof(opts->lockfile))
		abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
}

/*
 * Acquire a file lock that indicates a client is trying to start and connect
 * to a server, before executing a command. The lock is released upon exit or

	const char *baseargv[] = {
		hgcmd,
		"serve",
		"--cmdserver", "chgunix",
		"--address", opts->sockname,
		"--daemon-postexec", "chdir:/",
	};
	size_t baseargvsize = sizeof(baseargv) / sizeof(baseargv[0]);
	size_t argsize = baseargvsize + opts->argsize + 1;

static hgclient_t *retryconnectcmdserver(struct cmdserveropts *opts, pid_t pid)
{
	static const struct timespec sleepreq = {0, 10 * 1000000};
	int pst = 0;

	debugmsg("try connect to %s repeatedly", opts->sockname);

	unsigned int timeoutsec = 60;  /* default: 60 seconds */
	const char *timeoutenv = getenv("CHGTIMEOUT");
	if (timeoutenv)
		sscanf(timeoutenv, "%u", &timeoutsec);

	for (unsigned int i = 0; !timeoutsec || i < timeoutsec * 100; i++) {
		hgclient_t *hgc = hgc_open(opts->sockname);
		if (hgc)
			return hgc;

		if (pid > 0) {
			/* collect zombie if child process fails to start */
			int r = waitpid(pid, &pst, WNOHANG);
			if (r != 0)

		}

		nanosleep(&sleepreq, NULL);
	}

	abortmsg("timed out waiting for cmdserver %s", opts->sockname);
	return NULL;

cleanup:
	if (WIFEXITED(pst)) {
		if (WEXITSTATUS(pst) == 0)

	 * address does not work. we do not want to connect to the server
	 * again because it will probably tell us the same thing. */
	if (sockname == opts->redirectsockname)
		unlink(opts->sockname);

	debugmsg("start cmdserver at %s", opts->sockname);

	pid_t pid = fork();
	if (pid < 0)
		abortmsg("failed to fork cmdserver process");
	if (pid == 0) {

30620:937c52f06709

#define UNIX_PATH_MAX (sizeof(((struct sockaddr_un *)NULL)->sun_path))
#endif

struct cmdserveropts {
	char sockname[UNIX_PATH_MAX];
	char initsockname[UNIX_PATH_MAX];
	char redirectsockname[UNIX_PATH_MAX];
	char lockfile[UNIX_PATH_MAX];
	size_t argsize;
	const char **args;
	int lockfd;

	if (r < 0 || (size_t)r >= sizeof(opts->sockname))
		abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
	r = snprintf(opts->lockfile, sizeof(opts->lockfile), lockfmt, basename);
	if (r < 0 || (size_t)r >= sizeof(opts->lockfile))
		abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
	r = snprintf(opts->initsockname, sizeof(opts->initsockname),
			"%s.%u", opts->sockname, (unsigned)getpid());
	if (r < 0 || (size_t)r >= sizeof(opts->initsockname))
		abortmsg("too long TMPDIR or CHGSOCKNAME (r = %d)", r);
}

/*
 * Acquire a file lock that indicates a client is trying to start and connect
 * to a server, before executing a command. The lock is released upon exit or

	const char *baseargv[] = {
		hgcmd,
		"serve",
		"--cmdserver", "chgunix",
		"--address", opts->initsockname,
		"--daemon-postexec", "chdir:/",
	};
	size_t baseargvsize = sizeof(baseargv) / sizeof(baseargv[0]);
	size_t argsize = baseargvsize + opts->argsize + 1;

static hgclient_t *retryconnectcmdserver(struct cmdserveropts *opts, pid_t pid)
{
	static const struct timespec sleepreq = {0, 10 * 1000000};
	int pst = 0;

	debugmsg("try connect to %s repeatedly", opts->initsockname);

	unsigned int timeoutsec = 60;  /* default: 60 seconds */
	const char *timeoutenv = getenv("CHGTIMEOUT");
	if (timeoutenv)
		sscanf(timeoutenv, "%u", &timeoutsec);

	for (unsigned int i = 0; !timeoutsec || i < timeoutsec * 100; i++) {
		hgclient_t *hgc = hgc_open(opts->initsockname);
		if (hgc) {
			debugmsg("rename %s to %s", opts->initsockname,
					opts->sockname);
			int r = rename(opts->initsockname, opts->sockname);
			if (r != 0)
				abortmsgerrno("cannot rename");
			return hgc;
		}

		if (pid > 0) {
			/* collect zombie if child process fails to start */
			int r = waitpid(pid, &pst, WNOHANG);
			if (r != 0)

		}

		nanosleep(&sleepreq, NULL);
	}

	abortmsg("timed out waiting for cmdserver %s", opts->initsockname);
	return NULL;

cleanup:
	if (WIFEXITED(pst)) {
		if (WEXITSTATUS(pst) == 0)

	 * address does not work. we do not want to connect to the server
	 * again because it will probably tell us the same thing. */
	if (sockname == opts->redirectsockname)
		unlink(opts->sockname);

	debugmsg("start cmdserver at %s", opts->initsockname);

	pid_t pid = fork();
	if (pid < 0)
		abortmsg("failed to fork cmdserver process");
	if (pid == 0) {