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skynet_main.c浅析
1.作为skynet的启动文件,主要完成了一些初始化和读取并存取配置文件内容的工作.在这里只将代码读取配置文件的部分抽取出来，就算没有skynet环境，这些代码也是可以运行的，了解以后再对照源码进行分析，希望能对理解skynet带来一些帮助
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
#include <assert.h>
#include "env.h"
{
int thread;
int harbor;
const char *deamon;
const char *module_path;
const char *bootstrap;
const char *logger;
const char *logservice;
};
optint(const char *key, int opt)
{
const char *str = env_getenv(key);
if (str == NULL)
{
char tmp[20];
sprintf(tmp, "%d", opt);
env_setenv(key, tmp);
return opt;
}
return strtol(str, NULL, 10);
}
optstring(const char *key, const char *opt)
{
const char *str = env_getenv(key);
if (str == NULL)
{
if (opt)
{
env_setenv(key, opt);
opt = env_getenv(key);
}
return opt;
}
return str;
}
local config_name = ...\
local f = assert(io.open(config_name))\
local code = assert(f:read \‘*a\‘)\
print(\"code is \", code)\
local function getenv(name) return assert(os.getenv(name), \‘os.getenv() failed: \‘ .. name) end\
code = string.gsub(code, \‘%$([%w_%d]+)\‘, getenv)\
f:close()\
print(\"code after replace is \", code)\
local result = {}\
assert(load(code,\‘=(load)\‘,\‘t\‘,result))()\
return result\
";
static void
_init_env(lua_State *L)
{
lua_pushnil(L);
while(lua_next(L, -2) != 0)
{
int keyt = lua_type(L, -2);
if (keyt != LUA_TSTRING)
{
fprintf(stderr, "Invalid, config table\n");
exit(1);
}
if (lua_type(L, -1) == LUA_TBOOLEAN)
{
int b = lua_toboolean(L, -1);
env_setenv(key, b ? "true" : "false");
}
else
{
const char *value = http://www.mamicode.com/lua_tostring(L, -1);
if (value =http://www.mamicode.com/= NULL)
{
fprintf(stderr, "Invalud config table key = %s\n", key);
exit(1);
}
env_setenv(key, value);
}
lua_pop(L, 1);
}
lua_pop(L, 1);
}
{
lua_pop(L, -(n) - 1);
}
sigign()
{
struct sigaction sa;
sa.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sa, 0);
return 0;
}
init_conf(struct config *conf)
{
conf->thread = optint("thread", 8);
conf->module_path = optstring("cpath", "./cservice/?.so");
conf->harbor = optint("harbor", 1);
conf->bootstrap = optstring("bootstrap", "snlua bootstrap");
conf->deamon = optstring("deamon", NULL);
conf->deamon = optstring("logger", NULL);
conf->logservice = optstring("logservice", "logger");
}
{
printf("thread: %s\n", env_getenv("thread"));
printf("harbor: %s\n", env_getenv("harbor"));
}
main(int argc, char *argv[])
{
const char *config_file = NULL;
if (argc > 1)
{
config_file = argv[1];
}
else
{
fprintf(stderr, "Need a config file. Please read skynet wiki : https://github.com/cloudwu/skynet/wiki/Config\n"
"usage: skynet configfilename\n");
}
sigign();
env_env_init();
struct config conf;
struct lua_State *L = luaL_newstate();
luaL_openlibs(L);
int err = luaL_loadstring(L, load_config);
assert(err == LUA_OK);
lua_pushstring(L, config_file);
if (err)
{
fprintf(stderr, "%s,\n", lua_tostring(L, -1));
lua_close(L);
return 1;
}
_init_env(L);
}
首先看main函数：
const char *config_file = NULL;
if (argc > 1){
config_file = argv[1];
}else{
fprintf(stderr, "Need a config file. Please read skynet wiki : https://github.com/cloudwu/skynet/wiki/Config\n""usage: skynet configfilename\n");
}
这句话是读取配置文件路径:正如运行skynet的命令行为：./skynet ./examples/config.我将config拿出来放到和可执行文件用级，运行方式为: ./test ./config
于是config_file = argv[1]便保存了配置文件名.
下面两句:sigign();env_env_init();
设置信号处理函数,调用env_env_init()初始化保存配置文件的环境,该函数在env.c中，对应的是skynet_env.c（这里内容是一样的）,代码如下:
env.c:
#include "spinlock.h"
#include "lauxlib.h"
#include "lua.h"
#include <stdlib.h>
#include <assert.h>
#include <error.h>
#include <string.h>
{
struct spinlock lock;
lua_State *L;
};
env_getenv(const char *key)
{
SPIN_LOCK(E);
lua_State *L = E->L;
lua_getglobal(L, key);
const char *result = lua_tostring(L, -1);
//nil may return if there is no such a key-pair.
lua_pop(L, 1);
SPIN_UNLOCK(E);
}
env_setenv(const char *key, const char *value)
{
SPIN_LOCK(E);
lua_State *L = E->L;
lua_getglobal(L, key);
//after getglobal , if there is a value crosponds to the key , then it will be pushed onto stack, otherwise nil is pushed
assert(lua_isnil(L, -1));
lua_pop(L, 1); //pop nil from the stack
lua_pushstring(L, value);
lua_setglobal(L, key); //after setglobal the value on the stack will be poped.
}
env_env_init()
{
E = (struct env*)malloc(sizeof(*E));
SPIN_INIT(E);
E->L = luaL_newstate();
}
由此可见env.c创建了静态变量 static struct env *E 来保存配置。
继续main函数：
struct lua_State *L = luaL_newstate();
luaL_openlibs(L);
int err = luaL_loadstring(L, load_config);
assert(err == LUA_OK);
lua_pushstring(L, config_file);err = lua_pcall(L, 1, 1, 0);
if (err){
fprintf(stderr, "%s,\n", lua_tostring(L, -1));lua_close(L);
return 1;
}
_init_env(L);
这几句话便完成了读取配置文件并保存到env.c中的E的lua虚拟机里.
int err = luaL_loadstring(L, load_config);
这句话将load_config作为一个chunk加载到打开的L的函数堆栈里，我们看一下load_config：
local config_name = ...\
local f = assert(io.open(config_name))\
local code = assert(f:read \‘*a\‘)\
print(\"code is \", code)\
local function getenv(name) return assert(os.getenv(name), \‘os.getenv() failed: \‘ .. name) end\
code = string.gsub(code, \‘%$([%w_%d]+)\‘, getenv)\
f:close()\
print(\"code after replace is \", code)\
local result = {}\
assert(load(code,\‘=(load)\‘,\‘t\‘,result))()\
return result\
";
发现load_config其实是一段lua代码字符串，load到函数栈上以后，便可以执行，
但是根据 local config_name = ...\ 看出，需要传入一个参数，也就是配置文件的路径那么如何传呢?继续看main函数lua_pushstring(L, config_file);这句话便将config_file这个字符串放到了栈上供
int err = luaL_loadstring(L, load_config);产生的chunk调用.
于是执行err = lua_pcall(L, 1, 1, 0);if (err){fprintf(stderr, "%s,\n", lua_tostring(L, -1));lua_close(L);return 1;}
这句话便是开始执行lua函数栈上的chunk，参数为刚才push进去的config_file，那么chunk做了哪些事情呢?
local f = assert(io.open(config_name))\
local code = assert(f:read \‘*a\‘)\
首先打开配置文件，并读取所有内容,接下来定义了一个函数:
local function getenv(name) return assert(os.getenv(name), \‘os.getenv() failed: \‘ .. name) end\
这个函数执行返回 os.getenv(name), 也就是name为环境变量的名称，这里得到其值例如： print(os.getenv("HOME")),便会输出$(HOME)对应的值，
接下来：code = string.gsub(code, \‘%$([%w_%d]+)\‘, getenv)\
可以看到用string.gsub来讲code（配置文件内容）中的$(...)环境变量用getenv中得到的来替换
.但是skynet中得config没有类似的环境变量，所以得到的code没有变化.
接下来
f:close()\
local result = {}
assert(load(code,\‘=(load)\‘,\‘t\‘,result))()\
return result
关闭配置文件，将code load到result表中，然后返回result表，
我们注意到我们调用lua_pcall（L， 1，1，0），因此，result表此时在栈顶的位置.到此为止，配置文件的内容已经存放在result表中，并且这个表在lua调用栈的栈顶
,接下来便是从栈上的表中读取表中的内容，然后存放到env中：紧接着调用
_init_env(L);
_init_env(lua_State *L)
{
lua_pushnil(L);
while(lua_next(L, -2) != 0)
{
int keyt = lua_type(L, -2);
if (keyt != LUA_TSTRING)
{
fprintf(stderr, "Invalid, config table\n");
exit(1);
}
if (lua_type(L, -1) == LUA_TBOOLEAN)
{
int b = lua_toboolean(L, -1);
env_setenv(key, b ? "true" : "false");
}
else
{
const char *value = http://www.mamicode.com/lua_tostring(L, -1);
if (value =http://www.mamicode.com/= NULL)
{
fprintf(stderr, "Invalud config table key = %s\n", key);
exit(1);
}
env_setenv(key, value);
}
lua_pop(L, 1);
}
lua_pop(L, 1);
}
这个函数是一个典型的读取table中以字符串作为键的table的内容,尤其是不知道table中的具体内容是什么的时候.
这里我们只知道是以键值对形式，且键是字符串，table为非数组。
上边我们知道此时lua函数栈的栈顶为存放了配置文件内容的table，那么这个函数就是挨个遍历table内容，并调用env_env_set（）来存放。
首先lua_next(L, -2)先将栈顶元素弹出然后将table中的一个键值对放到栈上，键在-2位置上，值在-1位置上。因为lua_next(L, -2)先弹栈顶元素，因此在调用之前先pushnil，放进一个nil在栈顶，调用lua_next() nil 被弹出然后table中的第一个键值对依次放到栈上,然后获得键值，调用 env_setenv()来存放内容到E。循环读取table的值，直到读完跳出循环。至此，config文件中的内容全部存放到env中的全局变量E中的虚拟机中，并可在其他地方调用来获得配置文件内容.最后：init_conf(&conf);test_env();lua_close(L);其实就是仿照skynet_main.c来测试，test_env()可以替换成skynet_start(&conf)来继续启动skynet，这里简单的用来测试。到此为止，读取config配置文件的工作就做完了，并保存到了env.c中的局部静态变量里。供其它地方使用配置。
基础有限，研究skynet时间有限，难免讲述不清或出现错误，望指正。最后贴出全部测试文件代码:
----------------------------------------------------------------------------------------------------------
start.c
#include "lualib.h"
#include "lauxlib.h"
#include <assert.h>
#include "env.h"
{
int thread;
int harbor;
const char *deamon;
const char *module_path;
const char *bootstrap;
const char *logger;
const char *logservice;
};
optint(const char *key, int opt)
{
const char *str = env_getenv(key);
if (str == NULL)
{
char tmp[20];
sprintf(tmp, "%d", opt);
env_setenv(key, tmp);
return opt;
}
return strtol(str, NULL, 10);
}
optstring(const char *key, const char *opt)
{
const char *str = env_getenv(key);
if (str == NULL)
{
if (opt)
{
env_setenv(key, opt);
opt = env_getenv(key);
}
return opt;
}
return str;
}
local config_name = ...\
local f = assert(io.open(config_name))\
local code = assert(f:read \‘*a\‘)\
print(\"code is \", code)\
local function getenv(name) return assert(os.getenv(name), \‘os.getenv() failed: \‘ .. name) end\
code = string.gsub(code, \‘%$([%w_%d]+)\‘, getenv)\
f:close()\
print(\"code after replace is \", code)\
local result = {}\
assert(load(code,\‘=(load)\‘,\‘t\‘,result))()\
return result\
";
static void
_init_env(lua_State *L)
{
lua_pushnil(L);
while(lua_next(L, -2) != 0)
{
int keyt = lua_type(L, -2);
if (keyt != LUA_TSTRING)
{
fprintf(stderr, "Invalid, config table\n");
exit(1);
}
if (lua_type(L, -1) == LUA_TBOOLEAN)
{
int b = lua_toboolean(L, -1);
env_setenv(key, b ? "true" : "false");
}
else
{
const char *value = http://www.mamicode.com/lua_tostring(L, -1);
if (value =http://www.mamicode.com/= NULL)
{
fprintf(stderr, "Invalud config table key = %s\n", key);
exit(1);
}
env_setenv(key, value);
}
lua_pop(L, 1);
}
lua_pop(L, 1);
}
{
lua_pop(L, -(n) - 1);
}
sigign()
{
struct sigaction sa;
sa.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sa, 0);
return 0;
}
init_conf(struct config *conf)
{
conf->thread = optint("thread", 8);
conf->module_path = optstring("cpath", "./cservice/?.so");
conf->harbor = optint("harbor", 1);
conf->bootstrap = optstring("bootstrap", "snlua bootstrap");
conf->deamon = optstring("deamon", NULL);
conf->deamon = optstring("logger", NULL);
conf->logservice = optstring("logservice", "logger");
}
{
printf("thread: %s\n", env_getenv("thread"));
printf("harbor: %s\n", env_getenv("harbor"));
}
main(int argc, char *argv[])
{
const char *config_file = NULL;
if (argc > 1)
{
config_file = argv[1];
}
else
{
fprintf(stderr, "Need a config file. Please read skynet wiki : https://github.com/cloudwu/skynet/wiki/Config\n"
"usage: skynet configfilename\n");
}
sigign();
env_env_init();
struct config conf;
struct lua_State *L = luaL_newstate();
luaL_openlibs(L);
int err = luaL_loadstring(L, load_config);
assert(err == LUA_OK);
lua_pushstring(L, config_file);
if (err)
{
fprintf(stderr, "%s,\n", lua_tostring(L, -1));
lua_close(L);
return 1;
}
_init_env(L);
}
env.c
#include "spinlock.h"
#include "lauxlib.h"
#include "lua.h"
#include <stdlib.h>
#include <assert.h>
#include <error.h>
#include <string.h>
{
struct spinlock lock;
lua_State *L;
};
env_getenv(const char *key)
{
SPIN_LOCK(E);
lua_State *L = E->L;
lua_getglobal(L, key);
const char *result = lua_tostring(L, -1);
//nil may return if there is no such a key-pair.
lua_pop(L, 1);
SPIN_UNLOCK(E);
}
env_setenv(const char *key, const char *value)
{
SPIN_LOCK(E);
lua_State *L = E->L;
lua_getglobal(L, key);
//after getglobal , if there is a value crosponds to the key , then it will be pushed onto stack, otherwise nil is pushed
assert(lua_isnil(L, -1));
lua_pop(L, 1); //pop nil from the stack
lua_pushstring(L, value);
lua_setglobal(L, key); //after setglobal the value on the stack will be poped.
}
env_env_init()
{
E = (struct env*)malloc(sizeof(*E));
SPIN_INIT(E);
E->L = luaL_newstate();
}
env.h
#define __ENV_H_
void env_setenv(const char *key, const char *value);
void env_env_init();
#define SKYNET_SPINLOCK_H
#define SPIN_LOCK(q) spinlock_lock(&(q)->lock);
#define SPIN_UNLOCK(q) spinlock_unlock(&(q)->lock);
#define SPIN_DESTROY(q) spinlock_destroy(&(q)->lock);
int lock;
};
spinlock_init(struct spinlock *lock) {
lock->lock = 0;
}
spinlock_lock(struct spinlock *lock) {
while (__sync_lock_test_and_set(&lock->lock,1)) {}
}
spinlock_trylock(struct spinlock *lock) {
return __sync_lock_test_and_set(&lock->lock,1) == 0;
}
spinlock_unlock(struct spinlock *lock) {
__sync_lock_release(&lock->lock);
}
spinlock_destroy(struct spinlock *lock) {
(void) lock;
}
// you can also replace to pthread_spinlock
pthread_mutex_t lock;
};
spinlock_init(struct spinlock *lock) {
pthread_mutex_init(&lock->lock, NULL);
}
spinlock_lock(struct spinlock *lock) {
pthread_mutex_lock(&lock->lock);
}
spinlock_trylock(struct spinlock *lock) {
return pthread_mutex_trylock(&lock->lock) == 0;
}
spinlock_unlock(struct spinlock *lock) {
pthread_mutex_unlock(&lock->lock);
}
spinlock_destroy(struct spinlock *lock) {
pthread_mutex_destroy(&lock->lock);
}
config
thread = 8
--logger = nil
logger = "userlog"
logservice = "snlua"
--logservice = "catlogger"
logpath = "./../../log/cat/"
harbor = 1
address = "127.0.0.1:2401"
master = "127.0.0.1:2013"
start = "main" -- main script
bootstrap = "snlua bootstrap" -- The service for bootstrap
standalone = "0.0.0.0:2013"
luaservice = "./../../service/logind/?.lua;./../../service/db/?.lua;./../../service/web/?.lua;./../../service/cat/?.lua;./../../service/?.lua;./service/?.lua"
lualoader = "lualib/loader.lua"
preload = "./../../lualib/preload.lua" -- run preload.lua before every lua service run
snax = root.."../logind/?.lua;"..root.."test/?.lua"
-- snax_interface_g = "snax_g"
cpath = "./../../cservice/?.so;./cservice/?.so"
-- daemon = "./skynet.pid"
makefile:
CFLAGS= -g -O2 -Wall
LUA_INC= /usr/include/lua5.2
$(CC) $(CFLAGS) -o $@ $^ -I$(LUA_INC) -llua5.2 -lpthread -lm
rm -f main
skynet_main.c浅析