void Curl_ssl_close_all(struct SessionHandle *data)
{
#ifdef USE_SSL
int i;
/* kill the session ID cache */
if(data->state.session) {
for(i=0; i< data->set.ssl.numsessions; i++)
/* the single-killer function handles empty table slots */
kill_session(&data->state.session[i]);
/* free the cache data */
free(data->state.session);
data->state.session = NULL;
}
#ifdef USE_SSLEAY
Curl_ossl_close_all(data);
#else
#ifdef USE_GNUTLS
Curl_gtls_close_all(data);
#endif /* USE_GNUTLS */
#endif /* USE_SSLEAY */
#else /* USE_SSL */
(void)data;
#endif /* USE_SSL */
}
int do_exit(long code)
{
int i;
free_page_tables(get_base(current->ldt[1]),get_limit(0x0f));
free_page_tables(get_base(current->ldt[2]),get_limit(0x17));
for (i=0 ; i<NR_TASKS ; i++)
if (task[i] && task[i]->father == current->pid) {
task[i]->father = 1;
if (task[i]->state == TASK_ZOMBIE)
/* assumption task[1] is always init */
(void) send_sig(SIGCHLD, task[1], 1);
}
for (i=0 ; i<NR_OPEN ; i++)
if (current->filp[i])
sys_close(i);
iput(current->pwd);
current->pwd=NULL;
iput(current->root);
current->root=NULL;
iput(current->executable);
current->executable=NULL;
if (current->leader && current->tty >= 0)
tty_table[current->tty].pgrp = 0;
if (last_task_used_math == current)
last_task_used_math = NULL;
if (current->leader)
kill_session();
current->state = TASK_ZOMBIE;
current->exit_code = code;
tell_father(current->father);
schedule();
return (-1); /* just to suppress warnings */
}
int do_exit(long code)
{
int i;
// TODO 待看页表
free_page_tables(get_base(current->ldt[1]),get_limit(0x0f));
free_page_tables(get_base(current->ldt[2]),get_limit(0x17));
/*
* 找出所有子进程，将它们的父亲设为 init 进程，将状态标记为僵尸
* 然后给 init 进程发送一个 SIGCHLD 信号，提醒 init 进程回收子进程
*/
for (i=0 ; i<NR_TASKS ; i++)
if (task[i] && task[i]->father == current->pid) {
task[i]->father = 1;
if (task[i]->state == TASK_ZOMBIE)
/* assumption task[1] is always init */
// 最后一个参数 1 代表 privilege，此处为强制发送
(void) send_sig(SIGCHLD, task[1], 1);
}
// TODO 关闭文件？
/*
* NR_OPEN 是一个进程可以打开的最大文件数
* 而 NR_FILE 是系统在某时刻的限制文件总数
*/
for (i=0 ; i<NR_OPEN ; i++)
if (current->filp[i])
sys_close(i);
// 进程的当前工作目录 inode
iput(current->pwd);
current->pwd=NULL;
// 进程的根目录 inode
iput(current->root);
current->root=NULL;
// 进程本身可执行文件的 inode
iput(current->executable);
current->executable=NULL;
if (current->leader && current->tty >= 0)
tty_table[current->tty].pgrp = 0;
if (last_task_used_math == current)
last_task_used_math = NULL;
/*
* 如果是 session leader 会话领头进程，则向该会话所有进程发送 SIGHUP 信号
* PID, PPID, PGID, SID
* http://unix.stackexchange.com/questions/18166/what-are-session-leaders-in-ps
* 在同一次 ssh 会话中，用户对应的 shell 最先被启动，成为 session leader，
* 所有在同一次会话中产生的进程 session id 都等于这个 session leader 的 pid
* 当 session leader 退出时，它会向所有同一 session 中的进程发送 SIGHUP，
* 这个信号是可以被捕获的，如果进程忽略这个 SIGHUP，它则可以以一个孤儿进程继续执行
* http://www.firefoxbug.com/index.php/archives/2782/
*/
if (current->leader)
kill_session();
// 将自己设为僵尸，设置退出状态码，同时告诉父进程回收子进程
current->state = TASK_ZOMBIE;
current->exit_code = code;
tell_father(current->father);
// 如果 tell_father 中找不到父进程，自己把自己释放掉了，那也不会有机会继续执行下面代码了
schedule();
return (-1); /* just to suppress warnings */
}
static int irc_on_delete(event_owner_t *owner, void *client_data)
{
irc_session_t *session = client_data;
if (session->party) {
partymember_delete(session->party, NULL, "Deleted!");
session->party = NULL;
}
kill_session(session);
return(0);
}
/*
* Delete the given session ID from the cache.
*/
void Curl_ssl_delsessionid(struct connectdata *conn, void *ssl_sessionid)
{
int i;
for(i=0; i< conn->data->set.ssl.numsessions; i++) {
struct curl_ssl_session *check = &conn->data->state.session[i];
if (check->sessionid == ssl_sessionid) {
kill_session(check);
break;
}
}
}
/*
* Store session id in the session cache. The ID passed on to this function
* must already have been extracted and allocated the proper way for the SSL
* layer. Curl_XXXX_session_free() will be called to free/kill the session ID
* later on.
*/
CURLcode Curl_ssl_addsessionid(struct connectdata *conn,
void *ssl_sessionid,
size_t idsize)
{
long i;
struct SessionHandle *data=conn->data; /* the mother of all structs */
struct curl_ssl_session *store = &data->state.session[0];
long oldest_age=data->state.session[0].age; /* zero if unused */
char *clone_host;
/* Even though session ID re-use might be disabled, that only disables USING
IT. We still store it here in case the re-using is again enabled for an
upcoming transfer */
clone_host = strdup(conn->host.name);
if(!clone_host)
return CURLE_OUT_OF_MEMORY; /* bail out */
/* Now we should add the session ID and the host name to the cache, (remove
the oldest if necessary) */
/* find an empty slot for us, or find the oldest */
for(i=1; (i<data->set.ssl.numsessions) &&
data->state.session[i].sessionid; i++) {
if(data->state.session[i].age < oldest_age) {
oldest_age = data->state.session[i].age;
store = &data->state.session[i];
}
}
if(i == data->set.ssl.numsessions)
/* cache is full, we must "kill" the oldest entry! */
kill_session(store);
else
store = &data->state.session[i]; /* use this slot */
/* now init the session struct wisely */
store->sessionid = ssl_sessionid;
store->idsize = idsize;
store->age = data->state.sessionage; /* set current age */
if (store->name)
/* free it if there's one already present */
free(store->name);
store->name = clone_host; /* clone host name */
store->remote_port = conn->remote_port; /* port number */
if(!Curl_clone_ssl_config(&conn->ssl_config, &store->ssl_config)) {
store->sessionid = NULL; /* let caller free sessionid */
free(clone_host);
return CURLE_OUT_OF_MEMORY;
}
return CURLE_OK;
}
/**
* Black list check result for try_connect call
* If connection to the peer is allowed request adddress and ???
*
* @param cls the message
* @param peer the peer
* @param address the address
* @param session the session
* @param result the result
*/
static void
connect_bl_check_cont (void *cls,
const struct GNUNET_PeerIdentity *peer,
const struct GNUNET_HELLO_Address *address,
struct GNUNET_ATS_Session *session,
int result)
{
struct GNUNET_MessageHeader *msg = cls;
if (GNUNET_OK == result)
{
/* Blacklist allows to speak to this peer, forward SYN to neighbours */
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Received SYN message from peer `%s' at `%s'\n",
GNUNET_i2s (peer),
GST_plugins_a2s (address));
if (GNUNET_OK !=
GST_neighbours_handle_session_syn (msg,
peer))
{
GST_blacklist_abort_matching (address,
session);
kill_session (address->transport_name,
session);
}
GNUNET_free (msg);
return;
}
GNUNET_free (msg);
if (GNUNET_SYSERR == result)
return; /* check was aborted, session destroyed */
/* Blacklist denies to speak to this peer */
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Discarding SYN message from `%s' due to denied blacklist check\n",
GNUNET_i2s (peer));
kill_session (address->transport_name,
session);
}
void Curl_ssl_close_all(struct SessionHandle *data)
{
long i;
/* kill the session ID cache */
if(data->state.session) {
for(i=0; i< data->set.ssl.numsessions; i++)
/* the single-killer function handles empty table slots */
kill_session(&data->state.session[i]);
/* free the cache data */
free(data->state.session);
data->state.session = NULL;
}
curlssl_close_all(data);
}
//// 程序退出处理程序。在系统调用的中断处理程序中被调用。
int
do_exit (long code) // code 是错误码。
{
int i;
// 释放当前进程代码段和数据段所占的内存页(free_page_tables()在mm/memory.c,105 行)。
free_page_tables (get_base (current->ldt[1]), get_limit (0x0f));
free_page_tables (get_base (current->ldt[2]), get_limit (0x17));
// 如果当前进程有子进程，就将子进程的father 置为1(其父进程改为进程1)。如果该子进程已经
// 处于僵死(ZOMBIE)状态，则向进程1 发送子进程终止信号SIGCHLD。
for (i = 0; i < NR_TASKS; i++)
if (task[i] && task[i]->father == current->pid)
{
task[i]->father = 1;
if (task[i]->state == TASK_ZOMBIE)
/* assumption task[1] is always init */
(void) send_sig (SIGCHLD, task[1], 1);
}
// 关闭当前进程打开着的所有文件。
for (i = 0; i < NR_OPEN; i++)
if (current->filp[i])
sys_close (i);
// 对当前进程工作目录pwd、根目录root 以及运行程序的i 节点进行同步操作，并分别置空。
iput (current->pwd);
current->pwd = NULL;
iput (current->root);
current->root = NULL;
iput (current->executable);
current->executable = NULL;
// 如果当前进程是领头(leader)进程并且其有控制的终端，则释放该终端。
if (current->leader && current->tty >= 0)
tty_table[current->tty].pgrp = 0;
// 如果当前进程上次使用过协处理器，则将last_task_used_math 置空。
if (last_task_used_math == current)
last_task_used_math = NULL;
// 如果当前进程是leader 进程，则终止所有相关进程。
if (current->leader)
kill_session ();
// 把当前进程置为僵死状态，并设置退出码。
current->state = TASK_ZOMBIE;
current->exit_code = code;
// 通知父进程，也即向父进程发送信号SIGCHLD -- 子进程将停止或终止。
tell_father (current->father);
schedule (); // 重新调度进程的运行。
return (-1); /* just to suppress warnings */
}
/*
* Store session id in the session cache. The ID passed on to this function
* must already have been extracted and allocated the proper way for the SSL
* layer. Curl_XXXX_session_free() will be called to free/kill the session ID
* later on.
*/
CURLcode Curl_ssl_addsessionid(struct connectdata *conn,
void *ssl_sessionid,
size_t idsize)
{
int i;
struct SessionHandle *data=conn->data; /* the mother of all structs */
struct curl_ssl_session *store = &data->state.session[0];
long oldest_age=data->state.session[0].age; /* zero if unused */
char *clone_host;
clone_host = strdup(conn->host.name);
if(!clone_host)
return CURLE_OUT_OF_MEMORY; /* bail out */
/* Now we should add the session ID and the host name to the cache, (remove
the oldest if necessary) */
/* find an empty slot for us, or find the oldest */
for(i=1; (i<data->set.ssl.numsessions) &&
data->state.session[i].sessionid; i++) {
if(data->state.session[i].age < oldest_age) {
oldest_age = data->state.session[i].age;
store = &data->state.session[i];
}
}
if(i == data->set.ssl.numsessions)
/* cache is full, we must "kill" the oldest entry! */
kill_session(store);
else
store = &data->state.session[i]; /* use this slot */
/* now init the session struct wisely */
store->sessionid = ssl_sessionid;
store->idsize = idsize;
store->age = data->state.sessionage; /* set current age */
store->name = clone_host; /* clone host name */
store->remote_port = conn->remote_port; /* port number */
if (!Curl_clone_ssl_config(&conn->ssl_config, &store->ssl_config))
return CURLE_OUT_OF_MEMORY;
return CURLE_OK;
}
/**
* Black list check result from blacklist check triggered when a
* plugin gave us a new session in #plugin_env_session_start(). If
* connection to the peer is disallowed, kill the session.
*
* @param cls NULL
* @param peer the peer
* @param address address associated with the request
* @param session session associated with the request
* @param result the result
*/
static void
plugin_env_session_start_bl_check_cont (void *cls,
const struct GNUNET_PeerIdentity *peer,
const struct GNUNET_HELLO_Address *address,
struct GNUNET_ATS_Session *session,
int result)
{
if (GNUNET_OK != result)
{
kill_session (address->transport_name,
session);
return;
}
if (GNUNET_YES !=
GNUNET_HELLO_address_check_option (address,
GNUNET_HELLO_ADDRESS_INFO_INBOUND))
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Informing verifier about inbound session's address `%s'\n",
GST_plugins_a2s (address));
GST_validation_handle_address (address);
}
}
/**
* Function called by the transport for each received message.
*
* @param cls closure, const char* with the name of the plugin we received the message from
* @param address address and (claimed) identity of the other peer
* @param message the message, NULL if we only care about
* learning about the delay until we should receive again
* @param session identifier used for this session (NULL for plugins
* that do not offer bi-directional communication to the sender
* using the same "connection")
* @return how long the plugin should wait until receiving more data
* (plugins that do not support this, can ignore the return value)
*/
struct GNUNET_TIME_Relative
GST_receive_callback (void *cls,
const struct GNUNET_HELLO_Address *address,
struct GNUNET_ATS_Session *session,
const struct GNUNET_MessageHeader *message)
{
const char *plugin_name = cls;
struct GNUNET_TIME_Relative ret;
uint16_t type;
ret = GNUNET_TIME_UNIT_ZERO;
if (NULL == message)
goto end;
type = ntohs (message->type);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Received message with type %u from peer `%s'\n",
type,
GNUNET_i2s (&address->peer));
GNUNET_STATISTICS_update (GST_stats,
gettext_noop ("# bytes total received"),
ntohs (message->size),
GNUNET_NO);
GST_neighbours_notify_data_recv (address,
message);
switch (type)
{
case GNUNET_MESSAGE_TYPE_HELLO_LEGACY:
/* Legacy HELLO message, discard */
return ret;
case GNUNET_MESSAGE_TYPE_HELLO:
if (GNUNET_OK != GST_validation_handle_hello (message))
{
GNUNET_break_op (0);
GST_blacklist_abort_matching (address,
session);
}
return ret;
case GNUNET_MESSAGE_TYPE_TRANSPORT_PING:
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Processing PING from `%s'\n",
GST_plugins_a2s (address));
if (GNUNET_OK !=
GST_validation_handle_ping (&address->peer,
message,
address,
session))
{
GST_blacklist_abort_matching (address,
session);
kill_session (plugin_name,
session);
}
break;
case GNUNET_MESSAGE_TYPE_TRANSPORT_PONG:
GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
"Processing PONG from `%s'\n",
GST_plugins_a2s (address));
if (GNUNET_OK != GST_validation_handle_pong (&address->peer, message))
{
GNUNET_break_op (0);
GST_blacklist_abort_matching (address,
session);
kill_session (plugin_name, session);
}
break;
case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN:
/* Do blacklist check if communication with this peer is allowed */
(void) GST_blacklist_test_allowed (&address->peer,
NULL,
&connect_bl_check_cont,
GNUNET_copy_message (message),
address,
session);
break;
case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN_ACK:
if (GNUNET_OK !=
GST_neighbours_handle_session_syn_ack (message,
address,
session))
{
GST_blacklist_abort_matching (address, session);
kill_session (plugin_name, session);
}
break;
case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_ACK:
if (GNUNET_OK !=
GST_neighbours_handle_session_ack (message,
address,
session))
{
GNUNET_break_op(0);
GST_blacklist_abort_matching (address, session);
kill_session (plugin_name, session);
}
break;
case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_DISCONNECT:
GST_neighbours_handle_disconnect_message (&address->peer,
message);
break;
case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_QUOTA:
GST_neighbours_handle_quota_message (&address->peer,
message);
break;
case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE:
GST_neighbours_keepalive (&address->peer,
message);
break;
case GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE_RESPONSE:
GST_neighbours_keepalive_response (&address->peer,
message);
break;
default:
/* should be payload */
GNUNET_STATISTICS_update (GST_stats,
gettext_noop ("# bytes payload received"),
ntohs (message->size),
GNUNET_NO);
ret = process_payload (address,
session,
message);
break;
}
end:
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Allowing receive from peer %s to continue in %s\n",
GNUNET_i2s (&address->peer),
GNUNET_STRINGS_relative_time_to_string (ret,
GNUNET_YES));
return ret;
}
