From d89ff0ad812cdf178b911843bc3e8c04b2f00845 Mon Sep 17 00:00:00 2001
From: lichao <lichao@aiotlink.com>
Date: 星期四, 03 六月 2021 10:29:51 +0800
Subject: [PATCH] center remove old shm on start.
---
src/defs.cpp | 98 +++++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 91 insertions(+), 7 deletions(-)
diff --git a/src/defs.cpp b/src/defs.cpp
index 57df1bc..9402b27 100644
--- a/src/defs.cpp
+++ b/src/defs.cpp
@@ -22,6 +22,7 @@
#include <boost/uuid/random_generator.hpp>
#include <boost/uuid/string_generator.hpp>
#include <boost/uuid/uuid.hpp>
+#include <sys/file.h>
namespace
{
@@ -76,8 +77,16 @@
static_assert(AllocSizeIndex[255] > uint32_t(-1), "Make sure alloc size correct.");
const int64_t kCenterInfoFixedAddress = 1024 * 4;
+const int64_t kShmMetaInfoFixedAddress = 1024 * 16;
-const boost::uuids::uuid kCenterInfoTag = boost::uuids::string_generator()("fc5007bd-0e62-4d91-95dc-948cf1f02e5a");
+const boost::uuids::uuid kMetaInfoTag = boost::uuids::string_generator()("fc5007bd-0e62-4d91-95dc-948cf1f02e5a");
+
+struct BHomeMetaInfo {
+ boost::uuids::uuid tag_;
+ std::atomic<uint64_t> shm_id_;
+ std::atomic<uint64_t> ssn_id_;
+};
+
struct CenterMetaInfo {
boost::uuids::uuid tag_;
CenterInfo info_;
@@ -88,16 +97,43 @@
template <class T = void>
T *Ptr(const int64_t offset) { return reinterpret_cast<T *>(offset); }
+class FileLock
+{
+public:
+ FileLock(const std::string &path) :
+ fd_(Open(path))
+ {
+ if (fd_ == -1) { throw std::runtime_error("error open file:" + path); }
+ }
+ ~FileLock() { Close(fd_); }
+ bool try_lock() { return fd_ != -1 && (flock(fd_, LOCK_EX | LOCK_NB) == 0); }
+ void unlock() { flock(fd_, LOCK_UN); }
+
+private:
+ static int Open(const std::string &path) { return open(path.c_str(), O_RDONLY, 0666); }
+ static int Close(int fd) { return close(fd); }
+ int fd_;
+ std::mutex mtx_;
+};
+
+SharedMemory &BHomeMetaShm()
+{
+ static std::string name("bhshmq_meta_v0");
+ static SharedMemory shm(name, 1024 * 128);
+ return shm;
+}
+
} // namespace
CenterInfo *GetCenterInfo(SharedMemory &shm)
{
auto pmeta = Ptr<CenterMetaInfo>(kCenterInfoFixedAddress + Addr(shm.get_address()));
- if (pmeta->tag_ == kCenterInfoTag) {
+ if (pmeta->tag_ == kMetaInfoTag) {
return &pmeta->info_;
}
return nullptr;
}
+
ShmSocket &DefaultSender(SharedMemory &shm)
{
typedef std::pair<void *, std::shared_ptr<ShmSocket>> Pair;
@@ -121,11 +157,57 @@
local_cache = store.back();
return *local_cache.second;
}
+
+BHomeMetaInfo *GetBHomeMeta()
+{
+ auto p = Ptr<BHomeMetaInfo>(kShmMetaInfoFixedAddress + Addr(BHomeMetaShm().get_address()));
+ return (p->tag_ == kMetaInfoTag) ? p : nullptr;
+}
+
+bool ShmMetaInit()
+{
+ SharedMemory &shm = BHomeMetaShm();
+
+ static FileLock fl("/dev/shm/" + shm.name());
+ if (!fl.try_lock()) { // single center instance only.
+ return false;
+ }
+
+ auto pmeta = GetBHomeMeta();
+ if (pmeta && pmeta->tag_ == kMetaInfoTag) {
+ // remove old shm
+ SharedMemory::Remove(BHomeShmName());
+ ++pmeta->shm_id_; // inc shm id
+ return true; // already exist.
+ } else {
+ Mutex *mutex = shm.FindOrCreate<Mutex>("bhshmq_meta_lock");
+ if (!mutex || !mutex->try_lock()) {
+ return false;
+ }
+ DEFER1(mutex->unlock());
+
+ auto base = Addr(shm.get_address());
+ auto offset = kShmMetaInfoFixedAddress;
+ void *p = shm.Alloc(offset * 2);
+ if (Addr(p) - base <= offset) {
+ pmeta = new (Ptr(offset + base)) BHomeMetaInfo;
+ pmeta->tag_ = kMetaInfoTag;
+ pmeta->shm_id_ = 100;
+ pmeta->ssn_id_ = 10000;
+ return true;
+ }
+ }
+ return false;
+}
+
// put center info at fixed memory position.
// as boost shm find object (find socket/mq by id, etc...) also locks inside,
// which node might crash inside and cause deadlock.
-bool CenterInit(SharedMemory &shm)
+bool CenterInit()
{
+ if (!ShmMetaInit()) { return false; }
+
+ SharedMemory &shm = BHomeShm();
Mutex *mutex = shm.FindOrCreate<Mutex>("shm_center_lock");
if (!mutex || !mutex->try_lock()) {
return false;
@@ -133,7 +215,7 @@
DEFER1(mutex->unlock());
auto pmeta = Ptr<CenterMetaInfo>(kCenterInfoFixedAddress + Addr(shm.get_address()));
- if (pmeta->tag_ == kCenterInfoTag) {
+ if (pmeta->tag_ == kMetaInfoTag) {
return true;
} else {
auto base = Addr(shm.get_address());
@@ -155,7 +237,7 @@
InitMQ(info.mq_center_, NextId());
InitMQ(info.mq_bus_, NextId());
- pmeta->tag_ = kCenterInfoTag;
+ pmeta->tag_ = kMetaInfoTag;
return true;
}
}
@@ -183,8 +265,10 @@
std::string BHomeShmName()
{
- return "bhome_default_shm_v0";
+ auto bhome_meta = Ptr<BHomeMetaInfo>(kShmMetaInfoFixedAddress + Addr(BHomeMetaShm().get_address()));
+ return "bhome_shmq_id_" + std::to_string(bhome_meta->shm_id_.load());
}
+
SharedMemory &BHomeShm()
{
static SharedMemory shm(BHomeShmName(), 1024 * 1024 * 512);
@@ -193,7 +277,7 @@
bool GlobalInit(SharedMemory &shm) { return GetCenterInfo(shm); }
-MQId NewSession() { return 10 * (++GetCenterInfo(BHomeShm())->mqid_); }
+MQId NewSession() { return 10 * (++GetBHomeMeta()->ssn_id_); }
void SetLastError(const int ec, const std::string &msg)
{
--
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