int
subsystems_init(void)
{
return subsystems_init_upto(MAX_SUBSYS_LEVEL);
}
/**
* Initialize all the subsystems whose level is less than or equal to
* <b>target_level</b>; exit on failure.
**/
int
subsystems_init_upto(int target_level)
{
// initialize the subsystem_initialized array
check_and_setup();
for (unsigned i = 0; i < n_tor_subsystems; ++i) {
const subsys_fns_t *sys = tor_subsystems[i];
if (!sys->supported)
continue;
if (sys->level > target_level)
break;
if (sys_initialized[i])
continue;
int r = 0;
if (sys->initialize) {
// Note that the logging subsystem is designed so that it does no harm
// to log a message in an uninitialized state. These messages will be
// discarded for now, however.
log_debug(LD_GENERAL, "Initializing %s", sys->name);
r = sys->initialize();
}
if (r < 0) {
fprintf(stderr, "BUG: subsystem %s (at %u) initialization failed.\n",
sys->name, i);
raw_assert_unreached_msg("A subsystem couldn't be initialized.");
}
sys_initialized[i] = true;
}
return 0;
}
/** Install the publish/subscribe relationships for all the subsystems. */
static void
pubsub_install(void)
{
pubsub_builder_t *builder = pubsub_builder_new();
int r = subsystems_add_pubsub(builder);
// tor_assert是tor中的断言机制，类似于其他语言抛出异常？
tor_assert(r == 0);
r = tor_mainloop_connect_pubsub(builder); // consumes builder
tor_assert(r == 0);
}
代码块的 code 表示运行tor_init()，传入的参数为之前定义的 argc 和 argv
具体 tor_init()分析请看第 2 节
{
int init_rv = tor_init(argc, argv);
if (init_rv) {
tor_free_all(0);
result = (init_rv < 0) ? -1 : 0;
goto done;
}
}
2. tor_init
tor_init()是 Tor command-line client 的主入口，返回“0”表示初始化系统成功
char progname[256];
int quiet = 0;
time_of_process_start = time(NULL);
// 初始化连接池
tor_init_connection_lists();
/* Have the log set up with our application name. */
tor_snprintf(progname, sizeof(progname), "Tor %s", get_version());
// 设置应用程序名称
log_set_application_name(progname);
/* Initialize the history structures. */
// 包括history_map()和bw_arrays_init()：带宽数组初始化
rep_hist_init();
/* Initialize the service cache. */
// 初始化服务描述符缓存
rend_cache_init();
addressmap_init(); /* Init the client dns cache. Do it always, since it's
* cheap. */
/* Initialize the HS subsystem. */
// 缓存Hidden Service子系统
hs_init();
根据命令行输入的参数情况来确定quiet的值，我认为quiet代表一个日志等级
Tor 默认状态下是在控制台打印notice级别以上的日志（errors > warnings > notice），如果配置文件中定义了在其他地方打印日志，则会停止在控制台打印日志
如果添加--hush选项，则告诉 Tor 仅在控制台打印warnings和errors级别的日志（可以理解为warnings级别以上）
如果添加--quiet选项，则告诉 Tor 不要在控制台打印任何日志
{
/* We search for the "quiet" option first, since it decides whether we
* will log anything at all to the command line. */
config_line_t *opts = NULL, *cmdline_opts = NULL;
const config_line_t *cl;
(void) config_parse_commandline(argc, argv, 1, &opts, &cmdline_opts);
for (cl = cmdline_opts; cl; cl = cl->next) {
// 注意strcmp是字符串相等返回0，所以这里代表选项中有--hush，后面亦然
if (!strcmp(cl->key, "--hush"))
quiet = 1;
if (!strcmp(cl->key, "--quiet") ||
!strcmp(cl->key, "--dump-config"))
quiet = 2;
/* The following options imply --hush */
if (!strcmp(cl->key, "--version") || !strcmp(cl->key, "--digests") ||
!strcmp(cl->key, "--list-torrc-options") ||
!strcmp(cl->key, "--library-versions") ||
!strcmp(cl->key, "--list-modules") ||
!strcmp(cl->key, "--hash-password") ||
!strcmp(cl->key, "-h") || !strcmp(cl->key, "--help")) {
if (quiet < 1)
quiet = 1;
}
}
config_free_lines(opts);
config_free_lines(cmdline_opts);
}
/* give it somewhere to log to initially */
switch (quiet) {
case 2:
/* no initial logging */
// quiet最高级别，在控制台不打印任何日志
break;
case 1:
// 仅打印级别 >= warnings的日志
add_temp_log(LOG_WARN);
break;
default:
// 默认日志级别： >= notice
add_temp_log(LOG_NOTICE);
}
quiet_level = quiet;
接下来就是从 torrc 初始化配置，具体看第 3 节的分析
// 利用options_init_from_torrc函数从torrc加载配置
int init_rv = options_init_from_torrc(argc,argv);
if (init_rv < 0) {
// 输入错误的配置项提示
log_err(LD_CONFIG,"Reading config failed--see warnings above.");
return -1;
} else if (init_rv > 0) {
// We succeeded, and should exit anyway -- probably the user just said
// "--version" or something like that.
return 1;
}
/** Configuration options set by command line. */
static config_line_t *global_cmdline_options = NULL;
/** Non-configuration options set by the command line */
static config_line_t *global_cmdline_only_options = NULL;
...
if (! have_parsed_cmdline) {
/* Or we could redo the list every time we pass this place.
* It does not really matter */
if (config_parse_commandline(argc, argv, 0, &global_cmdline_options,
&global_cmdline_only_options) < 0) {
goto err;
}
// 如果从command-line获取配置项成功，标记为1
have_parsed_cmdline = 1;
}
cmdline_only_options = global_cmdline_only_options;
