int
test_curve(void)
{
    spiro_cp path[] = {
	{334, 117, 'v'},
	{305, 176, 'v'},
	{212, 142, 'c'},
	{159, 171, 'c'},
	{224, 237, 'c'},
	{347, 335, 'c'},
	{202, 467, 'c'},
	{81, 429, 'v'},
	{114, 368, 'v'},
	{201, 402, 'c'},
	{276, 369, 'c'},
	{218, 308, 'c'},
	{91, 211, 'c'},
	{124, 111, 'c'},
	{229, 82, 'c'}
    };
    spiro_seg *segs;
    int i;

    n = 1;
    for (i = 0; i < 1000; i++) {
	segs = setup_path(path, 15);
	solve_spiro(segs, 15);
    }
    printf("100 800 translate 1 -1 scale 1 setlinewidth\n");
    print_segs(segs, 15);
    printf("showpage\n");
    return 0;
}

static void
make_path( sliceable_switch *sliceable_switch, uint64_t in_datapath_id, uint16_t in_port, uint16_t in_vid,
           uint64_t out_datapath_id, uint16_t out_port, uint16_t out_vid, const buffer *packet ) {
  dlist_element *hops = resolve_path( sliceable_switch->pathresolver, in_datapath_id, in_port, out_datapath_id, out_port );
  if ( hops == NULL ) {
    warn( "No available path found ( %#" PRIx64 ":%u -> %#" PRIx64 ":%u ).",
          in_datapath_id, in_port, out_datapath_id, out_port );
    discard_packet_in( in_datapath_id, in_port, packet );
    return;
  }

  // check if the packet is ARP or not
  if ( sliceable_switch->handle_arp_with_packetout && packet_type_arp( packet ) ) {
    // send packet out for tail switch
    free_hop_list( hops );
    output_packet( packet, out_datapath_id, out_port, out_vid );
    return;
  }

  const uint32_t wildcards = 0;
  struct ofp_match match;
  set_match_from_packet( &match, in_port, wildcards, packet );

  if ( lookup_path( in_datapath_id, match, PRIORITY ) != NULL ) {
    warn( "Duplicated path found." );
    output_packet( packet, out_datapath_id, out_port, out_vid );
    return;
  }

  const uint16_t hard_timeout = 0;
  path *p = create_path( match, PRIORITY, sliceable_switch->idle_timeout, hard_timeout );
  assert( p != NULL );
  for ( dlist_element *e = get_first_element( hops ); e != NULL; e = e->next ) {
    pathresolver_hop *rh = e->data;
    hop *h = create_hop( rh->dpid, rh->in_port_no, rh->out_port_no, NULL );
    assert( h != NULL );
    append_hop_to_path( p, h );
  } // for(;;)

  dlist_element *e = get_last_element( hops );
  pathresolver_hop *last_hop = e->data;
  packet_out_params *params = xmalloc( sizeof( struct packet_out_params ) );
  params->packet = duplicate_buffer( packet );
  params->out_datapath_id = last_hop->dpid;
  params->out_port_no = last_hop->out_port_no;
  params->out_vid = out_vid;

  bool ret = setup_path( p, handle_setup, params, NULL, NULL );
  if ( ret != true ) {
    error( "Failed to set up path." );
    output_packet( packet, out_datapath_id, out_port, out_vid );
    free_buffer( params->packet );
    xfree( params );
  }

  delete_path( p );

  // free them
  free_hop_list( hops );
}

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;

	add_alternate_refs();
	write_head_info();
	clear_extra_refs();

	/* 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_receive_hook(post_receive_hook);
		run_update_post_hook(commands);
	}
	return 0;
}

int cmd_main(int argc, const char **argv)
{
	char *method = getenv("REQUEST_METHOD");
	char *dir;
	struct service_cmd *cmd = NULL;
	char *cmd_arg = NULL;
	int i;
	struct strbuf hdr = STRBUF_INIT;

	set_die_routine(die_webcgi);
	set_die_is_recursing_routine(die_webcgi_recursing);

	if (!method)
		die("No REQUEST_METHOD from server");
	if (!strcmp(method, "HEAD"))
		method = "GET";
	dir = getdir();

	for (i = 0; i < ARRAY_SIZE(services); i++) {
		struct service_cmd *c = &services[i];
		regex_t re;
		regmatch_t out[1];

		if (regcomp(&re, c->pattern, REG_EXTENDED))
			die("Bogus regex in service table: %s", c->pattern);
		if (!regexec(&re, dir, 1, out, 0)) {
			size_t n;

			if (strcmp(method, c->method))
				return bad_request(&hdr, c);

			cmd = c;
			n = out[0].rm_eo - out[0].rm_so;
			cmd_arg = xmemdupz(dir + out[0].rm_so + 1, n - 1);
			dir[out[0].rm_so] = 0;
			break;
		}
		regfree(&re);
	}

	if (!cmd)
		not_found(&hdr, "Request not supported: '%s'", dir);

	setup_path();
	if (!enter_repo(dir, 0))
		not_found(&hdr, "Not a git repository: '%s'", dir);
	git_config(git_default_config, NULL);
	if (!getenv("GIT_HTTP_EXPORT_ALL") &&
	    access("git-daemon-export-ok", F_OK) )
		not_found(&hdr, "Repository not exported: '%s'", dir);

	http_config();
	max_request_buffer = git_env_ulong("GIT_HTTP_MAX_REQUEST_BUFFER",
					   max_request_buffer);

	cmd->imp(&hdr, cmd_arg);
	return 0;
}

spiro_seg *
run_spiro(const spiro_cp *src, int n)
{
    int nseg = src[0].ty == '{' ? n - 1 : n;
    spiro_seg *s = setup_path(src, n);
    if (nseg > 1)
	solve_spiro(s, nseg);
    return s;
}

int cmd_main(int argc, const char **argv)
{
	const char *dir;
	int strict = 0;
	struct option options[] = {
		OPT_BOOL(0, "stateless-rpc", &stateless_rpc,
			 N_("quit after a single request/response exchange")),
		OPT_BOOL(0, "advertise-refs", &advertise_refs,
			 N_("exit immediately after initial ref advertisement")),
		OPT_BOOL(0, "strict", &strict,
			 N_("do not try <directory>/.git/ if <directory> is no Git directory")),
		OPT_INTEGER(0, "timeout", &timeout,
			    N_("interrupt transfer after <n> seconds of inactivity")),
		OPT_END()
	};

	packet_trace_identity("upload-pack");
	check_replace_refs = 0;

	argc = parse_options(argc, argv, NULL, options, upload_pack_usage, 0);

	if (argc != 1)
		usage_with_options(upload_pack_usage, options);

	if (timeout)
		daemon_mode = 1;

	setup_path();

	dir = argv[0];

	if (!enter_repo(dir, strict))
		die("'%s' does not appear to be a git repository", dir);

	git_config(upload_pack_config, NULL);

	switch (determine_protocol_version_server()) {
	case protocol_v1:
		/*
		 * v1 is just the original protocol with a version string,
		 * so just fall through after writing the version string.
		 */
		if (advertise_refs || !stateless_rpc)
			packet_write_fmt(1, "version 1\n");

		/* fallthrough */
	case protocol_v0:
		upload_pack();
		break;
	case protocol_unknown_version:
		BUG("unknown protocol version");
	}

	return 0;
}

int main(int argc, char **argv)
{
	char *dir;
	int i;
	int strict = 0;

	git_setup_gettext();

	packet_trace_identity("upload-pack");
	git_extract_argv0_path(argv[0]);
	read_replace_refs = 0;

	for (i = 1; i < argc; i++) {
		char *arg = argv[i];

		if (arg[0] != '-')
			break;
		if (!strcmp(arg, "--advertise-refs")) {
			advertise_refs = 1;
			continue;
		}
		if (!strcmp(arg, "--stateless-rpc")) {
			stateless_rpc = 1;
			continue;
		}
		if (!strcmp(arg, "--strict")) {
			strict = 1;
			continue;
		}
		if (!prefixcmp(arg, "--timeout=")) {
			timeout = atoi(arg+10);
			daemon_mode = 1;
			continue;
		}
		if (!strcmp(arg, "--")) {
			i++;
			break;
		}
	}

	if (i != argc-1)
		usage(upload_pack_usage);

	setup_path();

	dir = argv[i];

	if (!enter_repo(dir, strict))
		die("'%s' does not appear to be a git repository", dir);
	if (is_repository_shallow())
		die("attempt to fetch/clone from a shallow repository");
	git_config(upload_pack_config, NULL);
	upload_pack();
	return 0;
}

static int do_cvs_cmd(const char *me, char *arg)
{
	const char *cvsserver_argv[3] = {
		"cvsserver", "server", NULL
	};

	if (!arg || strcmp(arg, "server"))
		die("git-cvsserver only handles server: %s", arg);

	setup_path();
	return execv_git_cmd(cvsserver_argv);
}

static void
gedit_app_win32_startup (GApplication *application)
{
	G_APPLICATION_CLASS (gedit_app_win32_parent_class)->startup (application);

	setup_path ();
	prep_console ();

	/* manually set name and icon */
	g_set_application_name("gedit");
	gtk_window_set_default_icon_name ("accessories-text-editor");
}

static void
setup_reverse_path( int status, const path *p, void *user_data ) {
  assert(user_data);

  packet_out_params *params = user_data;
  if ( status != SETUP_SUCCEEDED ) {
    error( "Failed to set up path ( status = %d ).", status );
    output_packet( params->packet, params->out_datapath_id, params->out_port_no, params->out_vid );
    free_buffer( params->packet );
    xfree( params );
    return;
  }

  struct ofp_match rmatch;
  set_ipv4_reverse_match( &rmatch, &(p->match) );
  rmatch.dl_vlan = params->out_vid;

  openflow_actions *vlan_actions;
  vlan_actions = create_openflow_actions_to_update_vid( params->out_vid, params->in_vid );

  path *rpath = create_path( rmatch, p->priority, p->idle_timeout, p->hard_timeout );
  assert( rpath != NULL );
  list_element *hops = p->hops;
  dlist_element *rhops = create_dlist();
  while ( hops != NULL ) {
    hop *h = hops->data;
    assert( h != NULL );
    hop *rh = create_hop( h->datapath_id, h->out_port, h->in_port, vlan_actions );
    if ( vlan_actions ) {
      delete_actions( vlan_actions );
      vlan_actions = NULL;
    }
    assert( rh != NULL );
    rhops = insert_before_dlist( rhops, rh );
    hops = hops->next;
  }
  while ( rhops != NULL && rhops->data != NULL ) {
    append_hop_to_path( rpath, ( hop * ) rhops->data );
    rhops = rhops->next;
  }
  bool ret = setup_path( rpath, handle_setup, params, NULL, NULL );
  if ( ret != true ) {
    error( "Failed to set up reverse path." );
    output_packet( params->packet, params->out_datapath_id, params->out_port_no, params->out_vid );
    free_buffer( params->packet );
    xfree( params );
  }

  delete_path( rpath );
  delete_dlist( rhops );
}

spiro_seg *
run_spiro(const spiro_cp *src, int n)
{
    if (src==NULL || n <= 0) return 0;
    int nseg = src[0].ty == '{' ? n - 1 : n;
    spiro_seg *s = setup_path(src, n);
    if (s) {
	int converged = 1 ; // this value is for when nseg == 1; else actual value determined below
	if (nseg > 1) converged = solve_spiro(s, nseg);
	if (converged) return s;
	free(s);
    }
    return 0;
}

static int do_generic_cmd(const char *me, char *arg)
{
	const char *my_argv[4];

	setup_path();
	if (!arg || !(arg = sq_dequote(arg)))
		die("bad argument");
	if (prefixcmp(me, "git-"))
		die("bad command");

	my_argv[0] = me + 4;
	my_argv[1] = arg;
	my_argv[2] = NULL;

	return execv_git_cmd(my_argv);
}

int main(int argc, char **argv)
{
	char *dir;
	int i;
	int strict = 0;

	git_extract_argv0_path(argv[0]);
	read_replace_refs = 0;

	for (i = 1; i < argc; i++) {
		char *arg = argv[i];

		if (arg[0] != '-')
			break;
		if (!strcmp(arg, "--strict")) {
			strict = 1;
			continue;
		}
		if (!prefixcmp(arg, "--timeout=")) {
			timeout = atoi(arg+10);
			daemon_mode = 1;
			continue;
		}
		if (!strcmp(arg, "--")) {
			i++;
			break;
		}
	}

	if (i != argc-1)
		usage(upload_pack_usage);

	setup_path();

	dir = argv[i];

	if (!enter_repo(dir, strict))
		die("'%s' does not appear to be a git repository", dir);
	if (is_repository_shallow())
		die("attempt to fetch/clone from a shallow repository");
	if (getenv("GIT_DEBUG_SEND_PACK"))
		debug_fd = atoi(getenv("GIT_DEBUG_SEND_PACK"));
	upload_pack();
	return 0;
}

int cmd_main(int argc, const char **argv)
{
	const char *dir;
	int strict = 0;
	struct option options[] = {
		OPT_BOOL(0, "stateless-rpc", &stateless_rpc,
			 N_("quit after a single request/response exchange")),
		OPT_BOOL(0, "advertise-refs", &advertise_refs,
			 N_("exit immediately after intial ref advertisement")),
		OPT_BOOL(0, "strict", &strict,
			 N_("do not try <directory>/.git/ if <directory> is no Git directory")),
		OPT_INTEGER(0, "timeout", &timeout,
			    N_("interrupt transfer after <n> seconds of inactivity")),
		OPT_END()
	};

	packet_trace_identity("upload-pack");
	check_replace_refs = 0;

	argc = parse_options(argc, argv, NULL, options, upload_pack_usage, 0);

	if (argc != 1)
		usage_with_options(upload_pack_usage, options);

	if (timeout)
		daemon_mode = 1;

	setup_path();

	dir = argv[0];

	if (!enter_repo(dir, strict))
		die("'%s' does not appear to be a git repository", dir);

	git_config(upload_pack_config, NULL);
	upload_pack();
	return 0;
}

int cmd_receive_pack(int argc, const char **argv, const char *prefix)
{
	int advertise_refs = 0;
	int i;
	struct command *commands;
	struct sha1_array shallow = SHA1_ARRAY_INIT;
	struct sha1_array ref = SHA1_ARRAY_INIT;
	struct shallow_info si;

	packet_trace_identity("receive-pack");

	argv++;
	for (i = 1; i < argc; i++) {
		const char *arg = *argv++;

		if (*arg == '-') {
			if (!strcmp(arg, "--quiet")) {
				quiet = 1;
				continue;
			}

			if (!strcmp(arg, "--advertise-refs")) {
				advertise_refs = 1;
				continue;
			}
			if (!strcmp(arg, "--stateless-rpc")) {
				stateless_rpc = 1;
				continue;
			}
			if (!strcmp(arg, "--reject-thin-pack-for-testing")) {
				fix_thin = 0;
				continue;
			}

			usage(receive_pack_usage);
		}
		if (service_dir)
			usage(receive_pack_usage);
		service_dir = arg;
	}
	if (!service_dir)
		usage(receive_pack_usage);

	setup_path();

	if (!enter_repo(service_dir, 0))
		die("'%s' does not appear to be a git repository", service_dir);

	git_config(receive_pack_config, NULL);
	if (cert_nonce_seed)
		push_cert_nonce = prepare_push_cert_nonce(service_dir, time(NULL));

	if (0 <= transfer_unpack_limit)
		unpack_limit = transfer_unpack_limit;
	else if (0 <= receive_unpack_limit)
		unpack_limit = receive_unpack_limit;

	if (advertise_refs || !stateless_rpc) {
		write_head_info();
	}
	if (advertise_refs)
		return 0;

	if ((commands = read_head_info(&shallow)) != NULL) {
		const char *unpack_status = NULL;

		prepare_shallow_info(&si, &shallow);
		if (!si.nr_ours && !si.nr_theirs)
			shallow_update = 0;
		if (!delete_only(commands)) {
			unpack_status = unpack_with_sideband(&si);
			update_shallow_info(commands, &si, &ref);
		}
		execute_commands(commands, unpack_status, &si);
		if (pack_lockfile)
			unlink_or_warn(pack_lockfile);
		if (report_status)
			report(commands, unpack_status);
		run_receive_hook(commands, "post-receive", 1);
		run_update_post_hook(commands);
		if (auto_gc) {
			const char *argv_gc_auto[] = {
				"gc", "--auto", "--quiet", NULL,
			};
			int opt = RUN_GIT_CMD | RUN_COMMAND_STDOUT_TO_STDERR;
			run_command_v_opt(argv_gc_auto, opt);
		}
		if (auto_update_server_info)
			update_server_info(0);
		clear_shallow_info(&si);
	}
	if (use_sideband)
		packet_flush(1);
	sha1_array_clear(&shallow);
	sha1_array_clear(&ref);
	free((void *)push_cert_nonce);
	return 0;
}

int main(int argc, char **av)
{
	const char **argv = (const char **) av;
	const char *cmd;

	startup_info = &git_startup_info;

	cmd = git_extract_argv0_path(argv[0]);
	if (!cmd)
		cmd = "git-help";

	/*
	 * Always open file descriptors 0/1/2 to avoid clobbering files
	 * in die().  It also avoids messing up when the pipes are dup'ed
	 * onto stdin/stdout/stderr in the child processes we spawn.
	 */
	sanitize_stdfds();

	git_setup_gettext();

	/*
	 * "git-xxxx" is the same as "git xxxx", but we obviously:
	 *
	 *  - cannot take flags in between the "git" and the "xxxx".
	 *  - cannot execute it externally (since it would just do
	 *    the same thing over again)
	 *
	 * So we just directly call the builtin handler, and die if
	 * that one cannot handle it.
	 */
	if (starts_with(cmd, "git-")) {
		cmd += 4;
		argv[0] = cmd;
		handle_builtin(argc, argv);
		die("cannot handle %s as a builtin", cmd);
	}

	/* Look for flags.. */
	argv++;
	argc--;
	handle_options(&argv, &argc, NULL);
	if (argc > 0) {
		if (starts_with(argv[0], "--"))
			argv[0] += 2;
	} else {
		/* The user didn't specify a command; give them help */
		commit_pager_choice();
		printf("usage: %s\n\n", git_usage_string);
		list_common_cmds_help();
		printf("\n%s\n", _(git_more_info_string));
		exit(1);
	}
	cmd = argv[0];

	/*
	 * We use PATH to find git commands, but we prepend some higher
	 * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
	 * environment, and the $(gitexecdir) from the Makefile at build
	 * time.
	 */
	setup_path();

	while (1) {
		static int done_help = 0;
		static int was_alias = 0;
		was_alias = run_argv(&argc, &argv);
		if (errno != ENOENT)
			break;
		if (was_alias) {
			fprintf(stderr, "Expansion of alias '%s' failed; "
				"'%s' is not a git command\n",
				cmd, argv[0]);
			exit(1);
		}
		if (!done_help) {
			cmd = argv[0] = help_unknown_cmd(cmd);
			done_help = 1;
		} else
			break;
	}

	fprintf(stderr, "Failed to run command '%s': %s\n",
		cmd, strerror(errno));

	return 1;
}

void env_init(const struct config_paths_t *paths /* or NULL */)
{
    /*
      env_read_only variables can not be altered directly by the user
    */

    const wchar_t * const ro_keys[] =
    {
        L"status",
        L"history",
        L"version",
        L"_",
        L"LINES",
        L"COLUMNS",
        L"PWD",
        //L"SHLVL", // will be inserted a bit lower down
        L"FISH_VERSION",
    };
    for (size_t i=0; i < sizeof ro_keys / sizeof *ro_keys; i++)
    {
        env_read_only.insert(ro_keys[i]);
    }

    /*
       Names of all dynamically calculated variables
       */
    env_electric.insert(L"history");
    env_electric.insert(L"status");
    env_electric.insert(L"umask");
    env_electric.insert(L"COLUMNS");
    env_electric.insert(L"LINES");

    top = new env_node_t;
    global_env = top;
    global = &top->env;

    /*
      Now the environemnt variable handling is set up, the next step
      is to insert valid data
    */

    /*
      Import environment variables
    */
    for (char **p = (environ ? environ : __environ); p && *p; p++)
    {
        const wcstring key_and_val = str2wcstring(*p); //like foo=bar
        size_t eql = key_and_val.find(L'=');
        if (eql == wcstring::npos)
        {
            // no equals found
            if (is_read_only(key_and_val) || is_electric(key_and_val)) continue;
            env_set(key_and_val, L"", ENV_EXPORT | ENV_GLOBAL);
        }
        else
        {
            wcstring key = key_and_val.substr(0, eql);
            if (is_read_only(key) || is_electric(key)) continue;
            wcstring val = key_and_val.substr(eql + 1);
            if (variable_is_colon_delimited_array(key))
            {
                std::replace(val.begin(), val.end(), L':', ARRAY_SEP);
            }

            env_set(key, val.c_str(), ENV_EXPORT | ENV_GLOBAL);
        }
    }

    /* Set the given paths in the environment, if we have any */
    if (paths != NULL)
    {
        env_set(FISH_DATADIR_VAR, paths->data.c_str(), ENV_GLOBAL);
        env_set(FISH_SYSCONFDIR_VAR, paths->sysconf.c_str(), ENV_GLOBAL);
        env_set(FISH_HELPDIR_VAR, paths->doc.c_str(), ENV_GLOBAL);
        env_set(FISH_BIN_DIR, paths->bin.c_str(), ENV_GLOBAL);
    }

    /*
      Set up the PATH variable
    */
    setup_path();

    /*
      Set up the USER variable
    */
    if (env_get_string(L"USER").missing_or_empty())
    {
        const struct passwd *pw = getpwuid(getuid());
        if (pw && pw->pw_name)
        {
            const wcstring uname = str2wcstring(pw->pw_name);
            env_set(L"USER", uname.c_str(), ENV_GLOBAL | ENV_EXPORT);
        }
    }

    /*
      Set up the version variables
    */
    wcstring version = str2wcstring(get_fish_version());
    env_set(L"version", version.c_str(), ENV_GLOBAL);
//.........这里部分代码省略.........

int main(int argc, const char **argv)
{
	int err;
	const char *cmd;
	char sbuf[STRERR_BUFSIZE];
	int value;

	/* libsubcmd init */
	exec_cmd_init("perf", PREFIX, PERF_EXEC_PATH, EXEC_PATH_ENVIRONMENT);
	pager_init(PERF_PAGER_ENVIRONMENT);

	/* The page_size is placed in util object. */
	page_size = sysconf(_SC_PAGE_SIZE);
	cache_line_size(&cacheline_size);

	if (sysctl__read_int("kernel/perf_event_max_stack", &value) == 0)
		sysctl_perf_event_max_stack = value;

	if (sysctl__read_int("kernel/perf_event_max_contexts_per_stack", &value) == 0)
		sysctl_perf_event_max_contexts_per_stack = value;

	cmd = extract_argv0_path(argv[0]);
	if (!cmd)
		cmd = "perf-help";

	srandom(time(NULL));

	perf_config__init();
	err = perf_config(perf_default_config, NULL);
	if (err)
		return err;
	set_buildid_dir(NULL);

	/* get debugfs/tracefs mount point from /proc/mounts */
	tracing_path_mount();

	/*
	 * "perf-xxxx" is the same as "perf xxxx", but we obviously:
	 *
	 *  - cannot take flags in between the "perf" and the "xxxx".
	 *  - cannot execute it externally (since it would just do
	 *    the same thing over again)
	 *
	 * So we just directly call the internal command handler. If that one
	 * fails to handle this, then maybe we just run a renamed perf binary
	 * that contains a dash in its name. To handle this scenario, we just
	 * fall through and ignore the "xxxx" part of the command string.
	 */
	if (strstarts(cmd, "perf-")) {
		cmd += 5;
		argv[0] = cmd;
		handle_internal_command(argc, argv);
		/*
		 * If the command is handled, the above function does not
		 * return undo changes and fall through in such a case.
		 */
		cmd -= 5;
		argv[0] = cmd;
	}
	if (strstarts(cmd, "trace")) {
#if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
		setup_path();
		argv[0] = "trace";
		return cmd_trace(argc, argv);
#else
		fprintf(stderr,
			"trace command not available: missing audit-libs devel package at build time.\n");
		goto out;
#endif
	}
	/* Look for flags.. */
	argv++;
	argc--;
	handle_options(&argv, &argc, NULL);
	commit_pager_choice();

	if (argc > 0) {
		if (strstarts(argv[0], "--"))
			argv[0] += 2;
	} else {
		/* The user didn't specify a command; give them help */
		printf("\n usage: %s\n\n", perf_usage_string);
		list_common_cmds_help();
		printf("\n %s\n\n", perf_more_info_string);
		goto out;
	}
	cmd = argv[0];

	test_attr__init();

	/*
	 * We use PATH to find perf commands, but we prepend some higher
	 * precedence paths: the "--exec-path" option, the PERF_EXEC_PATH
	 * environment, and the $(perfexecdir) from the Makefile at build
	 * time.
	 */
	setup_path();
	/*
	 * Block SIGWINCH notifications so that the thread that wants it can
	 * unblock and get syscalls like select interrupted instead of waiting
//.........这里部分代码省略.........

int main(int argc, const char **argv)
{
	const char *cmd;

	cmd = perf_extract_argv0_path(argv[0]);
	if (!cmd)
		cmd = "perf-help";
	
	debugfs_mount(NULL);
	if (!prefixcmp(cmd, "perf-")) {
		cmd += 5;
		argv[0] = cmd;
		handle_internal_command(argc, argv);
		die("cannot handle %s internally", cmd);
	}

	
	argv++;
	argc--;
	handle_options(&argv, &argc, NULL);
	commit_pager_choice();
	set_buildid_dir();

	if (argc > 0) {
		if (!prefixcmp(argv[0], "--"))
			argv[0] += 2;
	} else {
		
		printf("\n usage: %s\n\n", perf_usage_string);
		list_common_cmds_help();
		printf("\n %s\n\n", perf_more_info_string);
		exit(1);
	}
	cmd = argv[0];

	setup_path();
	pthread__block_sigwinch();

	while (1) {
		static int done_help;
		static int was_alias;

		was_alias = run_argv(&argc, &argv);
		if (errno != ENOENT)
			break;

		if (was_alias) {
			fprintf(stderr, "Expansion of alias '%s' failed; "
				"'%s' is not a perf-command\n",
				cmd, argv[0]);
			exit(1);
		}
		if (!done_help) {
			cmd = argv[0] = help_unknown_cmd(cmd);
			done_help = 1;
		} else
			break;
	}

	fprintf(stderr, "Failed to run command '%s': %s\n",
		cmd, strerror(errno));

	return 1;
}

void env_init(const struct config_paths_t *paths /* or NULL */)
{
    /*
      env_read_only variables can not be altered directly by the user
    */

    const wchar_t * const ro_keys[] =
    {
        L"status",
        L"history",
        L"version",
        L"_",
        L"LINES",
        L"COLUMNS",
        L"PWD",
        L"SHLVL",
        L"FISH_VERSION",
    };
    for (size_t i=0; i < sizeof ro_keys / sizeof *ro_keys; i++)
    {
        env_read_only.insert(ro_keys[i]);
    }

    /*
      HOME and USER should be writeable by root, since this can be a
      convenient way to install software.
    */
    if (getuid() != 0)
    {
        env_read_only.insert(L"HOME");
        env_read_only.insert(L"USER");
    }

    /*
       Names of all dynamically calculated variables
       */
    env_electric.insert(L"history");
    env_electric.insert(L"status");
    env_electric.insert(L"umask");

    top = new env_node_t;
    global_env = top;
    global = &top->env;

    /*
      Now the environemnt variable handling is set up, the next step
      is to insert valid data
    */

    /*
      Import environment variables
    */
    for (char **p = (environ ? environ : __environ); p && *p; p++)
    {
        const wcstring key_and_val = str2wcstring(*p); //like foo=bar
        size_t eql = key_and_val.find(L'=');
        if (eql == wcstring::npos)
        {
            // no equals found
            env_set(key_and_val, L"", ENV_EXPORT);
        }
        else
        {
            wcstring key = key_and_val.substr(0, eql);
            wcstring val = key_and_val.substr(eql + 1);
            if (variable_can_be_array(val))
            {
                std::replace(val.begin(), val.end(), L':', ARRAY_SEP);
            }

            env_set(key, val.c_str(), ENV_EXPORT | ENV_GLOBAL);
        }
    }

    /* Set the given paths in the environment, if we have any */
    if (paths != NULL)
    {
        env_set(FISH_DATADIR_VAR, paths->data.c_str(), ENV_GLOBAL | ENV_EXPORT);
        env_set(FISH_SYSCONFDIR_VAR, paths->sysconf.c_str(), ENV_GLOBAL | ENV_EXPORT);
        env_set(FISH_HELPDIR_VAR, paths->doc.c_str(), ENV_GLOBAL | ENV_EXPORT);
        env_set(FISH_BIN_DIR, paths->bin.c_str(), ENV_GLOBAL | ENV_EXPORT);
    }

    /*
      Set up the PATH variable
    */
    setup_path();

    /*
      Set up the USER variable
    */
    const struct passwd *pw = getpwuid(getuid());
    if (pw && pw->pw_name)
    {
        const wcstring uname = str2wcstring(pw->pw_name);
        env_set(L"USER", uname.c_str(), ENV_GLOBAL | ENV_EXPORT);
    }

    /*
      Set up the version variables
//.........这里部分代码省略.........