Nginx学习笔记（六）源码分析&启动过程

Nginx的启动过程

　　主要介绍Nginx的启动过程，可以在/core/nginx.c中找到Nginx的主函数main()，那么就从这里开始分析Nginx的启动过程。

涉及到的基本函数

源码：

   1 /*
   2  * Copyright (C) Igor Sysoev
   3  * Copyright (C) Nginx, Inc.
   4  */
   5 
   6 
   7 #include <ngx_config.h>
   8 #include <ngx_core.h>
   9 #include <nginx.h>
  10 
  11 
  12 static ngx_int_t ngx_add_inherited_sockets(ngx_cycle_t *cycle);
  13 static ngx_int_t ngx_get_options(int argc, char *const *argv);
  14 static ngx_int_t ngx_process_options(ngx_cycle_t *cycle);
  15 static ngx_int_t ngx_save_argv(ngx_cycle_t *cycle, int argc, char *const *argv);
  16 static void *ngx_core_module_create_conf(ngx_cycle_t *cycle);
  17 static char *ngx_core_module_init_conf(ngx_cycle_t *cycle, void *conf);
  18 static char *ngx_set_user(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
  19 static char *ngx_set_env(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
  20 static char *ngx_set_priority(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
  21 static char *ngx_set_cpu_affinity(ngx_conf_t *cf, ngx_command_t *cmd,
  22     void *conf);
  23 static char *ngx_set_worker_processes(ngx_conf_t *cf, ngx_command_t *cmd,
  24     void *conf);
  25 
  26 
  27 static ngx_conf_enum_t  ngx_debug_points[] = {
  28     { ngx_string("stop"), NGX_DEBUG_POINTS_STOP },
  29     { ngx_string("abort"), NGX_DEBUG_POINTS_ABORT },
  30     { ngx_null_string, 0 }
  31 };
  32 
  33 
  34 static ngx_command_t  ngx_core_commands[] = {
  35 
  36     { ngx_string("daemon"),
  37       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_FLAG,
  38       ngx_conf_set_flag_slot,
  39       0,
  40       offsetof(ngx_core_conf_t, daemon),
  41       NULL },
  42 
  43     { ngx_string("master_process"),
  44       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_FLAG,
  45       ngx_conf_set_flag_slot,
  46       0,
  47       offsetof(ngx_core_conf_t, master),
  48       NULL },
  49 
  50     { ngx_string("timer_resolution"),
  51       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
  52       ngx_conf_set_msec_slot,
  53       0,
  54       offsetof(ngx_core_conf_t, timer_resolution),
  55       NULL },
  56 
  57     { ngx_string("pid"),
  58       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
  59       ngx_conf_set_str_slot,
  60       0,
  61       offsetof(ngx_core_conf_t, pid),
  62       NULL },
  63 
  64     { ngx_string("lock_file"),
  65       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
  66       ngx_conf_set_str_slot,
  67       0,
  68       offsetof(ngx_core_conf_t, lock_file),
  69       NULL },
  70 
  71     { ngx_string("worker_processes"),
  72       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
  73       ngx_set_worker_processes,
  74       0,
  75       0,
  76       NULL },
  77 
  78     { ngx_string("debug_points"),
  79       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
  80       ngx_conf_set_enum_slot,
  81       0,
  82       offsetof(ngx_core_conf_t, debug_points),
  83       &ngx_debug_points },
  84 
  85     { ngx_string("user"),
  86       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE12,
  87       ngx_set_user,
  88       0,
  89       0,
  90       NULL },
  91 
  92     { ngx_string("worker_priority"),
  93       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
  94       ngx_set_priority,
  95       0,
  96       0,
  97       NULL },
  98 
  99     { ngx_string("worker_cpu_affinity"),
 100       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_1MORE,
 101       ngx_set_cpu_affinity,
 102       0,
 103       0,
 104       NULL },
 105 
 106     { ngx_string("worker_rlimit_nofile"),
 107       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
 108       ngx_conf_set_num_slot,
 109       0,
 110       offsetof(ngx_core_conf_t, rlimit_nofile),
 111       NULL },
 112 
 113     { ngx_string("worker_rlimit_core"),
 114       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
 115       ngx_conf_set_off_slot,
 116       0,
 117       offsetof(ngx_core_conf_t, rlimit_core),
 118       NULL },
 119 
 120     { ngx_string("worker_rlimit_sigpending"),
 121       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
 122       ngx_conf_set_num_slot,
 123       0,
 124       offsetof(ngx_core_conf_t, rlimit_sigpending),
 125       NULL },
 126 
 127     { ngx_string("working_directory"),
 128       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
 129       ngx_conf_set_str_slot,
 130       0,
 131       offsetof(ngx_core_conf_t, working_directory),
 132       NULL },
 133 
 134     { ngx_string("env"),
 135       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
 136       ngx_set_env,
 137       0,
 138       0,
 139       NULL },
 140 
 141 #if (NGX_THREADS)
 142 
 143     { ngx_string("worker_threads"),
 144       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
 145       ngx_conf_set_num_slot,
 146       0,
 147       offsetof(ngx_core_conf_t, worker_threads),
 148       NULL },
 149 
 150     { ngx_string("thread_stack_size"),
 151       NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
 152       ngx_conf_set_size_slot,
 153       0,
 154       offsetof(ngx_core_conf_t, thread_stack_size),
 155       NULL },
 156 
 157 #endif
 158 
 159       ngx_null_command
 160 };
 161 
 162 
 163 static ngx_core_module_t  ngx_core_module_ctx = {
 164     ngx_string("core"),
 165     ngx_core_module_create_conf,
 166     ngx_core_module_init_conf
 167 };
 168 
 169 
 170 ngx_module_t  ngx_core_module = {
 171     NGX_MODULE_V1,
 172     &ngx_core_module_ctx,                  /* module context */
 173     ngx_core_commands,                     /* module directives */
 174     NGX_CORE_MODULE,                       /* module type */
 175     NULL,                                  /* init master */
 176     NULL,                                  /* init module */
 177     NULL,                                  /* init process */
 178     NULL,                                  /* init thread */
 179     NULL,                                  /* exit thread */
 180     NULL,                                  /* exit process */
 181     NULL,                                  /* exit master */
 182     NGX_MODULE_V1_PADDING
 183 };
 184 
 185 
 186 ngx_uint_t          ngx_max_module;
 187 
 188 static ngx_uint_t   ngx_show_help;
 189 static ngx_uint_t   ngx_show_version;
 190 static ngx_uint_t   ngx_show_configure;
 191 static u_char      *ngx_prefix;
 192 static u_char      *ngx_conf_file;
 193 static u_char      *ngx_conf_params;
 194 static char        *ngx_signal;
 195 
 196 
 197 static char **ngx_os_environ;
 198 
 199 
 200 int ngx_cdecl
 201 main(int argc, char *const *argv)
 202 {
 203     ngx_int_t         i;
 204     ngx_log_t        *log;
 205     ngx_cycle_t      *cycle, init_cycle;
 206     ngx_core_conf_t  *ccf;
 207 
 208     ngx_debug_init();
 209 
 210     if (ngx_strerror_init() != NGX_OK) {
 211         return 1;
 212     }
 213 
 214     if (ngx_get_options(argc, argv) != NGX_OK) {
 215         return 1;
 216     }
 217 
 218     if (ngx_show_version) {
 219         ngx_write_stderr("nginx version: " NGINX_VER NGX_LINEFEED);
 220 
 221         if (ngx_show_help) {
 222             ngx_write_stderr(
 223                 "Usage: nginx [-?hvVtq] [-s signal] [-c filename] "
 224                              "[-p prefix] [-g directives]" NGX_LINEFEED
 225                              NGX_LINEFEED
 226                 "Options:" NGX_LINEFEED
 227                 "  -?,-h         : this help" NGX_LINEFEED
 228                 "  -v            : show version and exit" NGX_LINEFEED
 229                 "  -V            : show version and configure options then exit"
 230                                    NGX_LINEFEED
 231                 "  -t            : test configuration and exit" NGX_LINEFEED
 232                 "  -q            : suppress non-error messages "
 233                                    "during configuration testing" NGX_LINEFEED
 234                 "  -s signal     : send signal to a master process: "
 235                                    "stop, quit, reopen, reload" NGX_LINEFEED
 236 #ifdef NGX_PREFIX
 237                 "  -p prefix     : set prefix path (default: "
 238                                    NGX_PREFIX ")" NGX_LINEFEED
 239 #else
 240                 "  -p prefix     : set prefix path (default: NONE)" NGX_LINEFEED
 241 #endif
 242                 "  -c filename   : set configuration file (default: "
 243                                    NGX_CONF_PATH ")" NGX_LINEFEED
 244                 "  -g directives : set global directives out of configuration "
 245                                    "file" NGX_LINEFEED NGX_LINEFEED
 246                 );
 247         }
 248 
 249         if (ngx_show_configure) {
 250             ngx_write_stderr(
 251 #ifdef NGX_COMPILER
 252                 "built by " NGX_COMPILER NGX_LINEFEED
 253 #endif
 254 #if (NGX_SSL)
 255 #ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
 256                 "TLS SNI support enabled" NGX_LINEFEED
 257 #else
 258                 "TLS SNI support disabled" NGX_LINEFEED
 259 #endif
 260 #endif
 261                 "configure arguments:" NGX_CONFIGURE NGX_LINEFEED);
 262         }
 263 
 264         if (!ngx_test_config) {
 265             return 0;
 266         }
 267     }
 268 
 269     /* TODO */ ngx_max_sockets = -1;
 270 
 271     ngx_time_init();
 272 
 273 #if (NGX_PCRE)
 274     ngx_regex_init();
 275 #endif
 276 
 277     ngx_pid = ngx_getpid();
 278 
 279     log = ngx_log_init(ngx_prefix);
 280     if (log == NULL) {
 281         return 1;
 282     }
 283 
 284     /* STUB */
 285 #if (NGX_OPENSSL)
 286     ngx_ssl_init(log);
 287 #endif
 288 
 289     /*
 290      * init_cycle->log is required for signal handlers and
 291      * ngx_process_options()
 292      */
 293 
 294     ngx_memzero(&init_cycle, sizeof(ngx_cycle_t));
 295     init_cycle.log = log;
 296     ngx_cycle = &init_cycle;
 297 
 298     init_cycle.pool = ngx_create_pool(1024, log);
 299     if (init_cycle.pool == NULL) {
 300         return 1;
 301     }
 302 
 303     if (ngx_save_argv(&init_cycle, argc, argv) != NGX_OK) {
 304         return 1;
 305     }
 306 
 307     if (ngx_process_options(&init_cycle) != NGX_OK) {
 308         return 1;
 309     }
 310 
 311     if (ngx_os_init(log) != NGX_OK) {
 312         return 1;
 313     }
 314 
 315     /*
 316      * ngx_crc32_table_init() requires ngx_cacheline_size set in ngx_os_init()
 317      */
 318 
 319     if (ngx_crc32_table_init() != NGX_OK) {
 320         return 1;
 321     }
 322 
 323     if (ngx_add_inherited_sockets(&init_cycle) != NGX_OK) {
 324         return 1;
 325     }
 326 
 327     ngx_max_module = 0;
 328     for (i = 0; ngx_modules[i]; i++) {
 329         ngx_modules[i]->index = ngx_max_module++;
 330     }
 331 
 332     cycle = ngx_init_cycle(&init_cycle);
 333     if (cycle == NULL) {
 334         if (ngx_test_config) {
 335             ngx_log_stderr(0, "configuration file %s test failed",
 336                            init_cycle.conf_file.data);
 337         }
 338 
 339         return 1;
 340     }
 341 
 342     if (ngx_test_config) {
 343         if (!ngx_quiet_mode) {
 344             ngx_log_stderr(0, "configuration file %s test is successful",
 345                            cycle->conf_file.data);
 346         }
 347 
 348         return 0;
 349     }
 350 
 351     if (ngx_signal) {
 352         return ngx_signal_process(cycle, ngx_signal);
 353     }
 354 
 355     ngx_os_status(cycle->log);
 356 
 357     ngx_cycle = cycle;
 358 
 359     ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
 360 
 361     if (ccf->master && ngx_process == NGX_PROCESS_SINGLE) {
 362         ngx_process = NGX_PROCESS_MASTER;
 363     }
 364 
 365 #if !(NGX_WIN32)
 366 
 367     if (ngx_init_signals(cycle->log) != NGX_OK) {
 368         return 1;
 369     }
 370 
 371     if (!ngx_inherited && ccf->daemon) {
 372         if (ngx_daemon(cycle->log) != NGX_OK) {
 373             return 1;
 374         }
 375 
 376         ngx_daemonized = 1;
 377     }
 378 
 379     if (ngx_inherited) {
 380         ngx_daemonized = 1;
 381     }
 382 
 383 #endif
 384 
 385     if (ngx_create_pidfile(&ccf->pid, cycle->log) != NGX_OK) {
 386         return 1;
 387     }
 388 
 389     if (cycle->log->file->fd != ngx_stderr) {
 390 
 391         if (ngx_set_stderr(cycle->log->file->fd) == NGX_FILE_ERROR) {
 392             ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
 393                           ngx_set_stderr_n " failed");
 394             return 1;
 395         }
 396     }
 397 
 398     if (log->file->fd != ngx_stderr) {
 399         if (ngx_close_file(log->file->fd) == NGX_FILE_ERROR) {
 400             ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
 401                           ngx_close_file_n " built-in log failed");
 402         }
 403     }
 404 
 405     ngx_use_stderr = 0;
 406 
 407     if (ngx_process == NGX_PROCESS_SINGLE) {
 408         ngx_single_process_cycle(cycle);
 409 
 410     } else {
 411         ngx_master_process_cycle(cycle);
 412     }
 413 
 414     return 0;
 415 }
 416 
 417 
 418 static ngx_int_t
 419 ngx_add_inherited_sockets(ngx_cycle_t *cycle)
 420 {
 421     u_char           *p, *v, *inherited;
 422     ngx_int_t         s;
 423     ngx_listening_t  *ls;
 424 
 425     inherited = (u_char *) getenv(NGINX_VAR);
 426 
 427     if (inherited == NULL) {
 428         return NGX_OK;
 429     }
 430 
 431     ngx_log_error(NGX_LOG_NOTICE, cycle->log, 0,
 432                   "using inherited sockets from \"%s\"", inherited);
 433 
 434     if (ngx_array_init(&cycle->listening, cycle->pool, 10,
 435                        sizeof(ngx_listening_t))
 436         != NGX_OK)
 437     {
 438         return NGX_ERROR;
 439     }
 440 
 441     for (p = inherited, v = p; *p; p++) {
 442         if (*p == ':' || *p == ';') {
 443             s = ngx_atoi(v, p - v);
 444             if (s == NGX_ERROR) {
 445                 ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
 446                               "invalid socket number \"%s\" in " NGINX_VAR
 447                               " environment variable, ignoring the rest"
 448                               " of the variable", v);
 449                 break;
 450             }
 451 
 452             v = p + 1;
 453 
 454             ls = ngx_array_push(&cycle->listening);
 455             if (ls == NULL) {
 456                 return NGX_ERROR;
 457             }
 458 
 459             ngx_memzero(ls, sizeof(ngx_listening_t));
 460 
 461             ls->fd = (ngx_socket_t) s;
 462         }
 463     }
 464 
 465     ngx_inherited = 1;
 466 
 467     return ngx_set_inherited_sockets(cycle);
 468 }
 469 
 470 
 471 char **
 472 ngx_set_environment(ngx_cycle_t *cycle, ngx_uint_t *last)
 473 {
 474     char             **p, **env;
 475     ngx_str_t         *var;
 476     ngx_uint_t         i, n;
 477     ngx_core_conf_t   *ccf;
 478 
 479     ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
 480 
 481     if (last == NULL && ccf->environment) {
 482         return ccf->environment;
 483     }
 484 
 485     var = ccf->env.elts;
 486 
 487     for (i = 0; i < ccf->env.nelts; i++) {
 488         if (ngx_strcmp(var[i].data, "TZ") == 0
 489             || ngx_strncmp(var[i].data, "TZ=", 3) == 0)
 490         {
 491             goto tz_found;
 492         }
 493     }
 494 
 495     var = ngx_array_push(&ccf->env);
 496     if (var == NULL) {
 497         return NULL;
 498     }
 499 
 500     var->len = 2;
 501     var->data = (u_char *) "TZ";
 502 
 503     var = ccf->env.elts;
 504 
 505 tz_found:
 506 
 507     n = 0;
 508 
 509     for (i = 0; i < ccf->env.nelts; i++) {
 510 
 511         if (var[i].data[var[i].len] == '=') {
 512             n++;
 513             continue;
 514         }
 515 
 516         for (p = ngx_os_environ; *p; p++) {
 517 
 518             if (ngx_strncmp(*p, var[i].data, var[i].len) == 0
 519                 && (*p)[var[i].len] == '=')
 520             {
 521                 n++;
 522                 break;
 523             }
 524         }
 525     }
 526 
 527     if (last) {
 528         env = ngx_alloc((*last + n + 1) * sizeof(char *), cycle->log);
 529         *last = n;
 530 
 531     } else {
 532         env = ngx_palloc(cycle->pool, (n + 1) * sizeof(char *));
 533     }
 534 
 535     if (env == NULL) {
 536         return NULL;
 537     }
 538 
 539     n = 0;
 540 
 541     for (i = 0; i < ccf->env.nelts; i++) {
 542 
 543         if (var[i].data[var[i].len] == '=') {
 544             env[n++] = (char *) var[i].data;
 545             continue;
 546         }
 547 
 548         for (p = ngx_os_environ; *p; p++) {
 549 
 550             if (ngx_strncmp(*p, var[i].data, var[i].len) == 0
 551                 && (*p)[var[i].len] == '=')
 552             {
 553                 env[n++] = *p;
 554                 break;
 555             }
 556         }
 557     }
 558 
 559     env[n] = NULL;
 560 
 561     if (last == NULL) {
 562         ccf->environment = env;
 563         environ = env;
 564     }
 565 
 566     return env;
 567 }
 568 
 569 
 570 ngx_pid_t
 571 ngx_exec_new_binary(ngx_cycle_t *cycle, char *const *argv)
 572 {
 573     char             **env, *var;
 574     u_char            *p;
 575     ngx_uint_t         i, n;
 576     ngx_pid_t          pid;
 577     ngx_exec_ctx_t     ctx;
 578     ngx_core_conf_t   *ccf;
 579     ngx_listening_t   *ls;
 580 
 581     ngx_memzero(&ctx, sizeof(ngx_exec_ctx_t));
 582 
 583     ctx.path = argv[0];
 584     ctx.name = "new binary process";
 585     ctx.argv = argv;
 586 
 587     n = 2;
 588     env = ngx_set_environment(cycle, &n);
 589     if (env == NULL) {
 590         return NGX_INVALID_PID;
 591     }
 592 
 593     var = ngx_alloc(sizeof(NGINX_VAR)
 594                     + cycle->listening.nelts * (NGX_INT32_LEN + 1) + 2,
 595                     cycle->log);
 596     if (var == NULL) {
 597         ngx_free(env);
 598         return NGX_INVALID_PID;
 599     }
 600 
 601     p = ngx_cpymem(var, NGINX_VAR "=", sizeof(NGINX_VAR));
 602 
 603     ls = cycle->listening.elts;
 604     for (i = 0; i < cycle->listening.nelts; i++) {
 605         p = ngx_sprintf(p, "%ud;", ls[i].fd);
 606     }
 607 
 608     *p = '\0';
 609 
 610     env[n++] = var;
 611 
 612 #if (NGX_SETPROCTITLE_USES_ENV)
 613 
 614     /* allocate the spare 300 bytes for the new binary process title */
 615 
 616     env[n++] = "SPARE=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
 617                "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
 618                "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
 619                "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
 620                "XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
 621 
 622 #endif
 623 
 624     env[n] = NULL;
 625 
 626 #if (NGX_DEBUG)
 627     {
 628     char  **e;
 629     for (e = env; *e; e++) {
 630         ngx_log_debug1(NGX_LOG_DEBUG_CORE, cycle->log, 0, "env: %s", *e);
 631     }
 632     }
 633 #endif
 634 
 635     ctx.envp = (char *const *) env;
 636 
 637     ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);
 638 
 639     if (ngx_rename_file(ccf->pid.data, ccf->oldpid.data) == NGX_FILE_ERROR) {
 640         ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
 641                       ngx_rename_file_n " %s to %s failed "
 642                       "before executing new binary process \"%s\"",
 643                       ccf->pid.data, ccf->oldpid.data, argv[0]);
 644 
 645         ngx_free(env);
 646         ngx_free(var);
 647 
 648         return NGX_INVALID_PID;
 649     }
 650 
 651     pid = ngx_execute(cycle, &ctx);
 652 
 653     if (pid == NGX_INVALID_PID) {
 654         if (ngx_rename_file(ccf->oldpid.data, ccf->pid.data)
 655             == NGX_FILE_ERROR)
 656         {
 657             ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
 658                           ngx_rename_file_n " %s back to %s failed after "
 659                           "an attempt to execute new binary process \"%s\"",
 660                           ccf->oldpid.data, ccf->pid.data, argv[0]);
 661         }
 662     }
 663 
 664     ngx_free(env);
 665     ngx_free(var);
 666 
 667     return pid;
 668 }
 669 
 670 
 671 static ngx_int_t
 672 ngx_get_options(int argc, char *const *argv)
 673 {
 674     u_char     *p;
 675     ngx_int_t   i;
 676 
 677     for (i = 1; i < argc; i++) {
 678 
 679         p = (u_char *) argv[i];
 680 
 681         if (*p++ != '-') {
 682             ngx_log_stderr(0, "invalid option: \"%s\"", argv[i]);
 683             return NGX_ERROR;
 684         }
 685 
 686         while (*p) {
 687 
 688             switch (*p++) {
 689 
 690             case '?':
 691             case 'h':
 692                 ngx_show_version = 1;
 693                 ngx_show_help = 1;
 694                 break;
 695 
 696             case 'v':
 697                 ngx_show_version = 1;
 698                 break;
 699 
 700             case 'V':
 701                 ngx_show_version = 1;
 702                 ngx_show_configure = 1;
 703                 break;
 704 
 705             case 't':
 706                 ngx_test_config = 1;
 707                 break;
 708 
 709             case 'q':
 710                 ngx_quiet_mode = 1;
 711                 break;
 712 
 713             case 'p':
 714                 if (*p) {
 715                     ngx_prefix = p;
 716                     goto next;
 717                 }
 718 
 719                 if (argv[++i]) {
 720                     ngx_prefix = (u_char *) argv[i];
 721                     goto next;
 722                 }
 723 
 724                 ngx_log_stderr(0, "option \"-p\" requires directory name");
 725                 return NGX_ERROR;
 726 
 727             case 'c':
 728                 if (*p) {
 729                     ngx_conf_file = p;
 730                     goto next;
 731                 }
 732 
 733                 if (argv[++i]) {
 734                     ngx_conf_file = (u_char *) argv[i];
 735                     goto next;
 736                 }
 737 
 738                 ngx_log_stderr(0, "option \"-c\" requires file name");
 739                 return NGX_ERROR;
 740 
 741             case 'g':
 742                 if (*p) {
 743                     ngx_conf_params = p;
 744                     goto next;
 745                 }
 746 
 747                 if (argv[++i]) {
 748                     ngx_conf_params = (u_char *) argv[i];
 749                     goto next;
 750                 }
 751 
 752                 ngx_log_stderr(0, "option \"-g\" requires parameter");
 753                 return NGX_ERROR;
 754 
 755             case 's':
 756                 if (*p) {
 757                     ngx_signal = (char *) p;
 758 
 759                 } else if (argv[++i]) {
 760                     ngx_signal = argv[i];
 761 
 762                 } else {
 763                     ngx_log_stderr(0, "option \"-s\" requires parameter");
 764                     return NGX_ERROR;
 765                 }
 766 
 767                 if (ngx_strcmp(ngx_signal, "stop") == 0
 768                     || ngx_strcmp(ngx_signal, "quit") == 0
 769                     || ngx_strcmp(ngx_signal, "reopen") == 0
 770                     || ngx_strcmp(ngx_signal, "reload") == 0)
 771                 {
 772                     ngx_process = NGX_PROCESS_SIGNALLER;
 773                     goto next;
 774                 }
 775 
 776                 ngx_log_stderr(0, "invalid option: \"-s %s\"", ngx_signal);
 777                 return NGX_ERROR;
 778 
 779             default:
 780                 ngx_log_stderr(0, "invalid option: \"%c\"", *(p - 1));
 781                 return NGX_ERROR;
 782             }
 783         }
 784 
 785     next:
 786 
 787         continue;
 788     }
 789 
 790     return NGX_OK;
 791 }
 792 
 793 
 794 static ngx_int_t
 795 ngx_save_argv(ngx_cycle_t *cycle, int argc, char *const *argv)
 796 {
 797 #if (NGX_FREEBSD)
 798 
 799     ngx_os_argv = (char **) argv;
 800     ngx_argc = argc;
 801     ngx_argv = (char **) argv;
 802 
 803 #else
 804     size_t     len;
 805     ngx_int_t  i;
 806 
 807     ngx_os_argv = (char **) argv;
 808     ngx_argc = argc;
 809 
 810     ngx_argv = ngx_alloc((argc + 1) * sizeof(char *), cycle->log);
 811     if (ngx_argv == NULL) {
 812         return NGX_ERROR;
 813     }
 814 
 815     for (i = 0; i < argc; i++) {
 816         len = ngx_strlen(argv[i]) + 1;
 817 
 818         ngx_argv[i] = ngx_alloc(len, cycle->log);
 819         if (ngx_argv[i] == NULL) {
 820             return NGX_ERROR;
 821         }
 822 
 823         (void) ngx_cpystrn((u_char *) ngx_argv[i], (u_char *) argv[i], len);
 824     }
 825 
 826     ngx_argv[i] = NULL;
 827 
 828 #endif
 829 
 830     ngx_os_environ = environ;
 831 
 832     return NGX_OK;
 833 }
 834 
 835 
 836 static ngx_int_t
 837 ngx_process_options(ngx_cycle_t *cycle)
 838 {
 839     u_char  *p;
 840     size_t   len;
 841 
 842     if (ngx_prefix) {
 843         len = ngx_strlen(ngx_prefix);
 844         p = ngx_prefix;
 845 
 846         if (len && !ngx_path_separator(p[len - 1])) {
 847             p = ngx_pnalloc(cycle->pool, len + 1);
 848             if (p == NULL) {
 849                 return NGX_ERROR;
 850             }
 851 
 852             ngx_memcpy(p, ngx_prefix, len);
 853             p[len++] = '/';
 854         }
 855 
 856         cycle->conf_prefix.len = len;
 857         cycle->conf_prefix.data = p;
 858         cycle->prefix.len = len;
 859         cycle->prefix.data = p;
 860 
 861     } else {
 862 
 863 #ifndef NGX_PREFIX
 864 
 865         p = ngx_pnalloc(cycle->pool, NGX_MAX_PATH);
 866         if (p == NULL) {
 867             return NGX_ERROR;
 868         }
 869 
 870         if (ngx_getcwd(p, NGX_MAX_PATH) == 0) {
 871             ngx_log_stderr(ngx_errno, "[emerg]: " ngx_getcwd_n " failed");
 872             return NGX_ERROR;
 873         }
 874 
 875         len = ngx_strlen(p);
 876 
 877         p[len++] = '/';
 878 
 879         cycle->conf_prefix.len = len;
 880         cycle->conf_prefix.data = p;
 881         cycle->prefix.len = len;
 882         cycle->prefix.data = p;
 883 
 884 #else
 885 
 886 #ifdef NGX_CONF_PREFIX
 887         ngx_str_set(&cycle->conf_prefix, NGX_CONF_PREFIX);
 888 #else
 889         ngx_str_set(&cycle->conf_prefix, NGX_PREFIX);
 890 #endif
 891         ngx_str_set(&cycle->prefix, NGX_PREFIX);
 892 
 893 #endif
 894     }
 895 
 896     if (ngx_conf_file) {
 897         cycle->conf_file.len = ngx_strlen(ngx_conf_file);
 898         cycle->conf_file.data = ngx_conf_file;
 899 
 900     } else {
 901         ngx_str_set(&cycle->conf_file, NGX_CONF_PATH);
 902     }
 903 
 904     if (ngx_conf_full_name(cycle, &cycle->conf_file, 0) != NGX_OK) {
 905         return NGX_ERROR;
 906     }
 907 
 908     for (p = cycle->conf_file.data + cycle->conf_file.len - 1;
 909          p > cycle->conf_file.data;
 910          p--)
 911     {
 912         if (ngx_path_separator(*p)) {
 913             cycle->conf_prefix.len = p - ngx_cycle->conf_file.data + 1;
 914             cycle->conf_prefix.data = ngx_cycle->conf_file.data;
 915             break;
 916         }
 917     }
 918 
 919     if (ngx_conf_params) {
 920         cycle->conf_param.len = ngx_strlen(ngx_conf_params);
 921         cycle->conf_param.data = ngx_conf_params;
 922     }
 923 
 924     if (ngx_test_config) {
 925         cycle->log->log_level = NGX_LOG_INFO;
 926     }
 927 
 928     return NGX_OK;
 929 }
 930 
 931 
 932 static void *
 933 ngx_core_module_create_conf(ngx_cycle_t *cycle)
 934 {
 935     ngx_core_conf_t  *ccf;
 936 
 937     ccf = ngx_pcalloc(cycle->pool, sizeof(ngx_core_conf_t));
 938     if (ccf == NULL) {
 939         return NULL;
 940     }
 941 
 942     /*
 943      * set by ngx_pcalloc()
 944      *
 945      *     ccf->pid = NULL;
 946      *     ccf->oldpid = NULL;
 947      *     ccf->priority = 0;
 948      *     ccf->cpu_affinity_n = 0;
 949      *     ccf->cpu_affinity = NULL;
 950      */
 951 
 952     ccf->daemon = NGX_CONF_UNSET;
 953     ccf->master = NGX_CONF_UNSET;
 954     ccf->timer_resolution = NGX_CONF_UNSET_MSEC;
 955 
 956     ccf->worker_processes = NGX_CONF_UNSET;
 957     ccf->debug_points = NGX_CONF_UNSET;
 958 
 959     ccf->rlimit_nofile = NGX_CONF_UNSET;
 960     ccf->rlimit_core = NGX_CONF_UNSET;
 961     ccf->rlimit_sigpending = NGX_CONF_UNSET;
 962 
 963     ccf->user = (ngx_uid_t) NGX_CONF_UNSET_UINT;
 964     ccf->group = (ngx_gid_t) NGX_CONF_UNSET_UINT;
 965 
 966 #if (NGX_THREADS)
 967     ccf->worker_threads = NGX_CONF_UNSET;
 968     ccf->thread_stack_size = NGX_CONF_UNSET_SIZE;
 969 #endif
 970 
 971     if (ngx_array_init(&ccf->env, cycle->pool, 1, sizeof(ngx_str_t))
 972         != NGX_OK)
 973     {
 974         return NULL;
 975     }
 976 
 977     return ccf;
 978 }
 979 
 980 
 981 static char *
 982 ngx_core_module_init_conf(ngx_cycle_t *cycle, void *conf)
 983 {
 984     ngx_core_conf_t  *ccf = conf;
 985 
 986     ngx_conf_init_value(ccf->daemon, 1);
 987     ngx_conf_init_value(ccf->master, 1);
 988     ngx_conf_init_msec_value(ccf->timer_resolution, 0);
 989 
 990     ngx_conf_init_value(ccf->worker_processes, 1);
 991     ngx_conf_init_value(ccf->debug_points, 0);
 992 
 993 #if (NGX_HAVE_CPU_AFFINITY)
 994 
 995     if (ccf->cpu_affinity_n
 996         && ccf->cpu_affinity_n != 1
 997         && ccf->cpu_affinity_n != (ngx_uint_t) ccf->worker_processes)
 998     {
 999         ngx_log_error(NGX_LOG_WARN, cycle->log, 0,
1000                       "the number of \"worker_processes\" is not equal to "
1001                       "the number of \"worker_cpu_affinity\" masks, "
1002                       "using last mask for remaining worker processes");
1003     }
1004 
1005 #endif
1006 
1007 #if (NGX_THREADS)
1008 
1009     ngx_conf_init_value(ccf->worker_threads, 0);
1010     ngx_threads_n = ccf->worker_threads;
1011     ngx_conf_init_size_value(ccf->thread_stack_size, 2 * 1024 * 1024);
1012 
1013 #endif
1014 
1015 
1016     if (ccf->pid.len == 0) {
1017         ngx_str_set(&ccf->pid, NGX_PID_PATH);
1018     }
1019 
1020     if (ngx_conf_full_name(cycle, &ccf->pid, 0) != NGX_OK) {
1021         return NGX_CONF_ERROR;
1022     }
1023 
1024     ccf->oldpid.len = ccf->pid.len + sizeof(NGX_OLDPID_EXT);
1025 
1026     ccf->oldpid.data = ngx_pnalloc(cycle->pool, ccf->oldpid.len);
1027     if (ccf->oldpid.data == NULL) {
1028         return NGX_CONF_ERROR;
1029     }
1030 
1031     ngx_memcpy(ngx_cpymem(ccf->oldpid.data, ccf->pid.data, ccf->pid.len),
1032                NGX_OLDPID_EXT, sizeof(NGX_OLDPID_EXT));
1033 
1034 
1035 #if !(NGX_WIN32)
1036 
1037     if (ccf->user == (uid_t) NGX_CONF_UNSET_UINT && geteuid() == 0) {
1038         struct group   *grp;
1039         struct passwd  *pwd;
1040 
1041         ngx_set_errno(0);
1042         pwd = getpwnam(NGX_USER);
1043         if (pwd == NULL) {
1044             ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
1045                           "getpwnam(\"" NGX_USER "\") failed");
1046             return NGX_CONF_ERROR;
1047         }
1048 
1049         ccf->username = NGX_USER;
1050         ccf->user = pwd->pw_uid;
1051 
1052         ngx_set_errno(0);
1053         grp = getgrnam(NGX_GROUP);
1054         if (grp == NULL) {
1055             ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
1056                           "getgrnam(\"" NGX_GROUP "\") failed");
1057             return NGX_CONF_ERROR;
1058         }
1059 
1060         ccf->group = grp->gr_gid;
1061     }
1062 
1063 
1064     if (ccf->lock_file.len == 0) {
1065         ngx_str_set(&ccf->lock_file, NGX_LOCK_PATH);
1066     }
1067 
1068     if (ngx_conf_full_name(cycle, &ccf->lock_file, 0) != NGX_OK) {
1069         return NGX_CONF_ERROR;
1070     }
1071 
1072     {
1073     ngx_str_t  lock_file;
1074 
1075     lock_file = cycle->old_cycle->lock_file;
1076 
1077     if (lock_file.len) {
1078         lock_file.len--;
1079 
1080         if (ccf->lock_file.len != lock_file.len
1081             || ngx_strncmp(ccf->lock_file.data, lock_file.data, lock_file.len)
1082                != 0)
1083         {
1084             ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,
1085                           "\"lock_file\" could not be changed, ignored");
1086         }
1087 
1088         cycle->lock_file.len = lock_file.len + 1;
1089         lock_file.len += sizeof(".accept");
1090 
1091         cycle->lock_file.data = ngx_pstrdup(cycle->pool, &lock_file);
1092         if (cycle->lock_file.data == NULL) {
1093             return NGX_CONF_ERROR;
1094         }
1095 
1096     } else {
1097         cycle->lock_file.len = ccf->lock_file.len + 1;
1098         cycle->lock_file.data = ngx_pnalloc(cycle->pool,
1099                                       ccf->lock_file.len + sizeof(".accept"));
1100         if (cycle->lock_file.data == NULL) {
1101             return NGX_CONF_ERROR;
1102         }
1103 
1104         ngx_memcpy(ngx_cpymem(cycle->lock_file.data, ccf->lock_file.data,
1105                               ccf->lock_file.len),
1106                    ".accept", sizeof(".accept"));
1107     }
1108     }
1109 
1110 #endif
1111 
1112     return NGX_CONF_OK;
1113 }
1114 
1115 
1116 static char *
1117 ngx_set_user(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
1118 {
1119 #if (NGX_WIN32)
1120 
1121     ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
1122                        "\"user\" is not supported, ignored");
1123 
1124     return NGX_CONF_OK;
1125 
1126 #else
1127 
1128     ngx_core_conf_t  *ccf = conf;
1129 
1130     char             *group;
1131     struct passwd    *pwd;
1132     struct group     *grp;
1133     ngx_str_t        *value;
1134 
1135     if (ccf->user != (uid_t) NGX_CONF_UNSET_UINT) {
1136         return "is duplicate";
1137     }
1138 
1139     if (geteuid() != 0) {
1140         ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
1141                            "the \"user\" directive makes sense only "
1142                            "if the master process runs "
1143                            "with super-user privileges, ignored");
1144         return NGX_CONF_OK;
1145     }
1146 
1147     value = (ngx_str_t *) cf->args->elts;
1148 
1149     ccf->username = (char *) value[1].data;
1150 
1151     ngx_set_errno(0);
1152     pwd = getpwnam((const char *) value[1].data);
1153     if (pwd == NULL) {
1154         ngx_conf_log_error(NGX_LOG_EMERG, cf, ngx_errno,
1155                            "getpwnam(\"%s\") failed", value[1].data);
1156         return NGX_CONF_ERROR;
1157     }
1158 
1159     ccf->user = pwd->pw_uid;
1160 
1161     group = (char *) ((cf->args->nelts == 2) ? value[1].data : value[2].data);
1162 
1163     ngx_set_errno(0);
1164     grp = getgrnam(group);
1165     if (grp == NULL) {
1166         ngx_conf_log_error(NGX_LOG_EMERG, cf, ngx_errno,
1167                            "getgrnam(\"%s\") failed", group);
1168         return NGX_CONF_ERROR;
1169     }
1170 
1171     ccf->group = grp->gr_gid;
1172 
1173     return NGX_CONF_OK;
1174 
1175 #endif
1176 }
1177 
1178 
1179 static char *
1180 ngx_set_env(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
1181 {
1182     ngx_core_conf_t  *ccf = conf;
1183 
1184     ngx_str_t   *value, *var;
1185     ngx_uint_t   i;
1186 
1187     var = ngx_array_push(&ccf->env);
1188     if (var == NULL) {
1189         return NGX_CONF_ERROR;
1190     }
1191 
1192     value = cf->args->elts;
1193     *var = value[1];
1194 
1195     for (i = 0; i < value[1].len; i++) {
1196 
1197         if (value[1].data[i] == '=') {
1198 
1199             var->len = i;
1200 
1201             return NGX_CONF_OK;
1202         }
1203     }
1204 
1205     return NGX_CONF_OK;
1206 }
1207 
1208 
1209 static char *
1210 ngx_set_priority(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
1211 {
1212     ngx_core_conf_t  *ccf = conf;
1213 
1214     ngx_str_t        *value;
1215     ngx_uint_t        n, minus;
1216 
1217     if (ccf->priority != 0) {
1218         return "is duplicate";
1219     }
1220 
1221     value = cf->args->elts;
1222 
1223     if (value[1].data[0] == '-') {
1224         n = 1;
1225         minus = 1;
1226 
1227     } else if (value[1].data[0] == '+') {
1228         n = 1;
1229         minus = 0;
1230 
1231     } else {
1232         n = 0;
1233         minus = 0;
1234     }
1235 
1236     ccf->priority = ngx_atoi(&value[1].data[n], value[1].len - n);
1237     if (ccf->priority == NGX_ERROR) {
1238         return "invalid number";
1239     }
1240 
1241     if (minus) {
1242         ccf->priority = -ccf->priority;
1243     }
1244 
1245     return NGX_CONF_OK;
1246 }
1247 
1248 
1249 static char *
1250 ngx_set_cpu_affinity(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
1251 {
1252 #if (NGX_HAVE_CPU_AFFINITY)
1253     ngx_core_conf_t  *ccf = conf;
1254 
1255     u_char            ch;
1256     uint64_t         *mask;
1257     ngx_str_t        *value;
1258     ngx_uint_t        i, n;
1259 
1260     if (ccf->cpu_affinity) {
1261         return "is duplicate";
1262     }
1263 
1264     mask = ngx_palloc(cf->pool, (cf->args->nelts - 1) * sizeof(uint64_t));
1265     if (mask == NULL) {
1266         return NGX_CONF_ERROR;
1267     }
1268 
1269     ccf->cpu_affinity_n = cf->args->nelts - 1;
1270     ccf->cpu_affinity = mask;
1271 
1272     value = cf->args->elts;
1273 
1274     for (n = 1; n < cf->args->nelts; n++) {
1275 
1276         if (value[n].len > 64) {
1277             ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
1278                          "\"worker_cpu_affinity\" supports up to 64 CPUs only");
1279             return NGX_CONF_ERROR;
1280         }
1281 
1282         mask[n - 1] = 0;
1283 
1284         for (i = 0; i < value[n].len; i++) {
1285 
1286             ch = value[n].data[i];
1287 
1288             if (ch == ' ') {
1289                 continue;
1290             }
1291 
1292             mask[n - 1] <<= 1;
1293 
1294             if (ch == '0') {
1295                 continue;
1296             }
1297 
1298             if (ch == '1') {
1299                 mask[n - 1] |= 1;
1300                 continue;
1301             }
1302 
1303             ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
1304                           "invalid character \"%c\" in \"worker_cpu_affinity\"",
1305                           ch);
1306             return NGX_CONF_ERROR;
1307         }
1308     }
1309 
1310 #else
1311 
1312     ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
1313                        "\"worker_cpu_affinity\" is not supported "
1314                        "on this platform, ignored");
1315 #endif
1316 
1317     return NGX_CONF_OK;
1318 }
1319 
1320 
1321 uint64_t
1322 ngx_get_cpu_affinity(ngx_uint_t n)
1323 {
1324     ngx_core_conf_t  *ccf;
1325 
1326     ccf = (ngx_core_conf_t *) ngx_get_conf(ngx_cycle->conf_ctx,
1327                                            ngx_core_module);
1328 
1329     if (ccf->cpu_affinity == NULL) {
1330         return 0;
1331     }
1332 
1333     if (ccf->cpu_affinity_n > n) {
1334         return ccf->cpu_affinity[n];
1335     }
1336 
1337     return ccf->cpu_affinity[ccf->cpu_affinity_n - 1];
1338 }
1339 
1340 
1341 static char *
1342 ngx_set_worker_processes(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
1343 {
1344     ngx_str_t        *value;
1345     ngx_core_conf_t  *ccf;
1346 
1347     ccf = (ngx_core_conf_t *) conf;
1348 
1349     if (ccf->worker_processes != NGX_CONF_UNSET) {
1350         return "is duplicate";
1351     }
1352 
1353     value = (ngx_str_t *) cf->args->elts;
1354 
1355     if (ngx_strcmp(value[1].data, "auto") == 0) {
1356         ccf->worker_processes = ngx_ncpu;
1357         return NGX_CONF_OK;
1358     }
1359 
1360     ccf->worker_processes = ngx_atoi(value[1].data, value[1].len);
1361 
1362     if (ccf->worker_processes == NGX_ERROR) {
1363         return "invalid value";
1364     }
1365 
1366     return NGX_CONF_OK;
1367 }

View Code

　　Nginx的启动包括了很多的初始化和处理函数。这些函数相对来说，有一部分非常复杂，暂且从简单开始，从整体上对Ngixnd的启动有一个了解，方便日后的分析与学习。

　　主要函数：

//完成socket的继承
static ngx_int_t ngx_add_inherited_sockets(ngx_cycle_t *cycle);
//对参数选项进行处理                           
static ngx_int_t ngx_get_options(int argc, char *const *argv);
//初始化ngx_cycle内的部分内容
static ngx_int_t ngx_process_options(ngx_cycle_t *cycle);
//命令行参数保存到ngx_os_argv、ngx_argc以及ngx_argv全局的变量中
static ngx_int_t ngx_save_argv(ngx_cycle_t *cycle, int argc, char *const *argv);
//创建模块的配置信息
static void *ngx_core_module_create_conf(ngx_cycle_t *cycle);
//初始化配置信息
static char *ngx_core_module_init_conf(ngx_cycle_t *cycle, void *conf);
static char *ngx_set_user(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static char *ngx_set_env(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
//设置优先级
static char *ngx_set_priority(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
//设置CPU亲和性
static char *ngx_set_cpu_affinity(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
//设置worker进程
static char *ngx_set_worker_processes(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);

Nginx启动的主要流程

　　下图为Nginx的启动时函数的调用过程，其中大部分都是为了Nginx启动的初始化部分。从错误处理、参数设置、时间设置等方面进行初始化，并注册了我们需要的模块，最后根据信号选择单任务模式还是master-worker模式。

　　流程图：

初始化

　　主函数在开始对系统错误、参数、时间、系统变量、日志等进行了初始化。

//初始化系统中错误编号对应的含义
ngx_strerror_init();
//对参数选项进行处理
ngx_get_options(argc, argv);
//时间初始化
ngx_time_init();
//重置pcre内存管理的接口
ngx_regex_init();
//日志初始化
ngx_log_init(ngx_prefix);
//创建内存池
ngx_create_pool(1024, log);
//保存变量
ngx_save_argv();
//初始化ngx_cycle的prefix, conf_prefix, conf_file, conf_param
ngx_process_options();
//初始化系统相关变量，如内存页面大小ngx_pagesize,ngx_cacheline_size,最大连接数ngx_max_sockets等
ngx_os_init();
//初始化CRC表(后续的CRC校验通过查表进行，效率高)
ngx_crc32_table_init();

主要工作

　　初始化完成后，需要先调用ngx_add_inherited_sockets函数继承socket，并储存在Listening数组中，在运行时候进行监听。之后就可以调用ngx_init_cycle来初始化ngx_cycle结构体，这个结构体用来存储所有的连接，具体如下：

struct ngx_cycle_s {
    void                  ****conf_ctx;//配置上下文数组(含所有模块)
    ngx_pool_t               *pool;//内存池

    ngx_log_t                *log;//日志
    ngx_log_t                 new_log;

    ngx_connection_t        **files;//连接文件    
    ngx_connection_t         *free_connections;//空闲连接
    ngx_uint_t                free_connection_n;//空闲连接数

    ngx_queue_t               reusable_connections_queue;////再利用连接队列  

    ngx_array_t               listening;//监听数组
    ngx_array_t               paths;//路径数组
    ngx_list_t                open_files;//打开文件链表
    ngx_list_t                shared_memory;//共享内存链表

    ngx_uint_t                connection_n;//连接个数  
    ngx_uint_t                files_n;//打开文件个数 

    ngx_connection_t         *connections;
    ngx_event_t              *read_events;//读事件    
    ngx_event_t              *write_events;//写事件

    ngx_cycle_t              *old_cycle;

    ngx_str_t                 conf_file;//配置文件  
    ngx_str_t                 conf_param;//配置参数
    ngx_str_t                 conf_prefix;//配置前缀
    ngx_str_t                 prefix;//前缀
    ngx_str_t                 lock_file;//锁文件
    ngx_str_t                 hostname;

　　调用ngx_init_signals来注册信号。

//信号种类
#define NGX_PROCESS_SINGLE 0
#define NGX_PROCESS_MASTER 1
#define NGX_PROCESS_SIGNALLER 2
#define NGX_PROCESS_WORKER 3
#define NGX_PROCESS_HELPER 4

　　在进入处理之前，还要调用ngx_create_pidfile来记录进程id。最后，根据接收到的信号，来判断调用ngx_single_process_cycle还是ngx_master_process_cycle（master-worker模式）。

if (ngx_process == NGX_PROCESS_SINGLE) {
        ngx_single_process_cycle(cycle);
} else {
        ngx_master_process_cycle(cycle);
}

　　其中，守护进程函数为ngx_daemon，位于src/os/unix/Ngx_daemon.c

//daemon
ngx_int_t
ngx_daemon(ngx_log_t *log)
{
    int  fd;
    switch (fork()) {
    case -1:
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "fork() failed");
        return NGX_ERROR;
    case 0:
        breakdefault:
        exit(0);
    }

    ngx_pid = ngx_getpid();//取得进程识别码

    if (setsid() == -1) {  //子进程将重新获得一个新的会话(session)id
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "setsid() failed");
        return NGX_ERROR;
    }

    umask(0);

    fd = open("/dev/null", O_RDWR);
    if (fd == -1) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,
                      "open(\"/dev/null\") failed");
        return NGX_ERROR;
    }

    if (dup2(fd, STDIN_FILENO) == -1) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "dup2(STDIN) failed");
        return NGX_ERROR;
    }

    if (dup2(fd, STDOUT_FILENO) == -1) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "dup2(STDOUT) failed");
        return NGX_ERROR;
    }

#if 0
    if (dup2(fd, STDERR_FILENO) == -1) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "dup2(STDERR) failed");
        return NGX_ERROR;
    }
#endif

    if (fd > STDERR_FILENO) {
        if (close(fd) == -1) {
            ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "close() failed");
            return NGX_ERROR;
        }
    }
    return NGX_OK;
}