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@ -1,3 +1,17 @@
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/*!
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什么是共享内存
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顾名思义，共享内存就是允许两个不相关的进程访问同一个物理内存。共享内存是在两个正在运行的进程之间
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共享和传递数据的一种非常有效的方式。不同进程之间共享的内存通常安排为同一段物理内存。进程可以将同
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一段共享内存连接到它们自己的地址空间中，所有进程都可以访问共享内存中的地址，就好像它们是由用C语言
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函数malloc()分配的内存一样。而如果某个进程向共享内存写入数据，所做的改动将立即影响到可以访问同一段
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共享内存的任何其他进程。
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特别提醒：共享内存并未提供同步机制，也就是说，在第一个进程结束对共享内存的写操作之前，并无自动机制
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可以阻止第二个进程开始对它进行读取。所以我们通常需要用其他的机制来同步对共享内存的访问
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共享线性区可以由任意的进程创建,每个使用共享线性区都必须经过映射.
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*/
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/*
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* Copyright (c) 2013-2019 Huawei Technologies Co., Ltd. All rights reserved.
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* Copyright (c) 2020-2023 Huawei Device Co., Ltd. All rights reserved.
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@ -55,9 +69,9 @@
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#ifdef LOSCFG_KERNEL_SHM
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#define SHM_SEG_FREE 0x2000
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#define SHM_SEG_USED 0x4000
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#define SHM_SEG_REMOVE 0x8000
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#define SHM_SEG_FREE 0x2000 //空闲未使用
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#define SHM_SEG_USED 0x4000 //已使用
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#define SHM_SEG_REMOVE 0x8000 //删除
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#ifndef SHM_M
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#define SHM_M 010000
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@ -66,21 +80,17 @@
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#ifndef SHM_X
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#define SHM_X 0100
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#endif
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#ifndef ACCESSPERMS
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#define ACCESSPERMS (S_IRWXU | S_IRWXG | S_IRWXO)
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#endif
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#define ACCESSPERMS (S_IRWXU | S_IRWXG | S_IRWXO)//文件权限值意思就是 用户,用户组,其他可读可写.
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#endif //代表含义U:user G:group O:other
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#define SHM_S_IRUGO (S_IRUSR | S_IRGRP | S_IROTH)
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#define SHM_S_IWUGO (S_IWUSR | S_IWGRP | S_IWOTH)
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#define SHM_S_IXUGO (S_IXUSR | S_IXGRP | S_IXOTH)
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#define SHM_GROUPE_TO_USER 3
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#define SHM_OTHER_TO_USER 6
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#ifndef LOSCFG_IPC_CONTAINER
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STATIC LosMux g_sysvShmMux;
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/* private data */
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STATIC struct shminfo g_shmInfo;
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STATIC struct shmIDSource *g_shmSegs = NULL;
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@ -96,6 +106,60 @@ STATIC UINT32 g_shmUsedPageCount;
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#define SYSV_SHM_LOCK() (VOID)LOS_MuxLock(&IPC_SHM_SYS_VSHM_MUTEX, LOS_WAIT_FOREVER)
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#define SYSV_SHM_UNLOCK() (VOID)LOS_MuxUnlock(&IPC_SHM_SYS_VSHM_MUTEX)
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#if 0 // @note_#if0
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//内核为每一个IPC对象保存一个ipc_perm结构体，该结构说明了IPC对象的权限和所有者
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struct ipc_perm {
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key_t __ipc_perm_key; //调用shmget()时给出的关键字
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uid_t uid; //共享内存所有者的有效用户ID
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gid_t gid; //共享内存所有者所属组的有效组ID
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uid_t cuid; //共享内存创建 者的有效用户ID
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gid_t cgid; //共享内存创建者所属组的有效组ID
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mode_t mode; //权限 + SHM_DEST / SHM_LOCKED /SHM_HUGETLB 标志位
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int __ipc_perm_seq; //序列号
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long __pad1; //保留扩展用
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long __pad2;
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};
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//每个共享内存段在内核中维护着一个内部结构shmid_ds
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struct shmid_ds {
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struct ipc_perm shm_perm;///< 操作许可，里面包含共享内存的用户ID、组ID等信息
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size_t shm_segsz; ///< 共享内存段的大小，单位为字节
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time_t shm_atime; ///< 最后一个进程访问共享内存的时间
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time_t shm_dtime; ///< 最后一个进程离开共享内存的时间
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time_t shm_ctime; ///< 创建时间
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pid_t shm_cpid; ///< 创建共享内存的进程ID
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pid_t shm_lpid; ///< 最后操作共享内存的进程ID
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unsigned long shm_nattch; ///< 当前使用该共享内存段的进程数量
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unsigned long __pad1; //保留扩展用
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unsigned long __pad2;
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};
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// 共享内存模块设置信息
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struct shminfo {
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unsigned long shmmax, shmmin, shmmni, shmseg, shmall, __unused[4];
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};
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struct shmIDSource {//共享内存描述符
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struct shmid_ds ds; //是内核为每一个共享内存段维护的数据结构
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UINT32 status; //状态 SHM_SEG_FREE ...
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LOS_DL_LIST node; //节点,挂VmPage
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#ifdef LOSCFG_SHELL
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CHAR ownerName[OS_PCB_NAME_LEN];
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#endif
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};
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/* private data */
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STATIC struct shminfo g_shmInfo = { //描述共享内存范围的全局变量
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.shmmax = SHM_MAX,//共享内存单个上限 4096页 即 16M
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.shmmin = SHM_MIN,//共享内存单个下限 1页 即:4K
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.shmmni = SHM_MNI,//共享内存总数 默认192
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.shmseg = SHM_SEG,//每个用户进程可以使用的最多的共享内存段的数目 128
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.shmall = SHM_ALL,//系统范围内共享内存的总页数, 4096页
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};
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STATIC struct shmIDSource *g_shmSegs = NULL;
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STATIC UINT32 g_shmUsedPageCount;
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#endif
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//共享内存初始化
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struct shmIDSource *OsShmCBInit(LosMux *sysvShmMux, struct shminfo *shmInfo, UINT32 *shmUsedPageCount)
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{
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UINT32 ret;
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@ -104,7 +168,6 @@ struct shmIDSource *OsShmCBInit(LosMux *sysvShmMux, struct shminfo *shmInfo, UIN
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if ((sysvShmMux == NULL) || (shmInfo == NULL) || (shmUsedPageCount == NULL)) {
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return NULL;
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}
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ret = LOS_MuxInit(sysvShmMux, NULL);
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if (ret != LOS_OK) {
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goto ERROR;
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@ -115,7 +178,6 @@ struct shmIDSource *OsShmCBInit(LosMux *sysvShmMux, struct shminfo *shmInfo, UIN
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shmInfo->shmmni = SHM_MNI;
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shmInfo->shmseg = SHM_SEG;
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shmInfo->shmall = SHM_ALL;
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struct shmIDSource *shmSegs = LOS_MemAlloc((VOID *)OS_SYS_MEM_ADDR, sizeof(struct shmIDSource) * shmInfo->shmmni);
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if (shmSegs == NULL) {
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(VOID)LOS_MuxDestroy(sysvShmMux);
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@ -125,9 +187,9 @@ struct shmIDSource *OsShmCBInit(LosMux *sysvShmMux, struct shminfo *shmInfo, UIN
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0, (sizeof(struct shmIDSource) * shmInfo->shmmni));
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for (i = 0; i < shmInfo->shmmni; i++) {
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shmSegs[i].status = SHM_SEG_FREE;
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shmSegs[i].ds.shm_perm.seq = i + 1;
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LOS_ListInit(&shmSegs[i].node);
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shmSegs[i].status = SHM_SEG_FREE;//节点初始状态为空闲
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shmSegs[i].ds.shm_perm.seq = i + 1;//struct ipc_perm shm_perm;系统为每一个IPC对象保存一个ipc_perm结构体,结构说明了IPC对象的权限和所有者
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LOS_ListInit(&shmSegs[i].node);//初始化节点
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}
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*shmUsedPageCount = 0;
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@ -137,7 +199,6 @@ ERROR:
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VM_ERR("ShmInit fail\n");
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return NULL;
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}
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UINT32 ShmInit(VOID)
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{
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#ifndef LOSCFG_IPC_CONTAINER
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@ -149,8 +210,9 @@ UINT32 ShmInit(VOID)
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return LOS_OK;
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}
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LOS_MODULE_INIT(ShmInit, LOS_INIT_LEVEL_VM_COMPLETE);
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LOS_MODULE_INIT(ShmInit, LOS_INIT_LEVEL_VM_COMPLETE);//共享内存模块初始化
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//共享内存反初始化
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UINT32 ShmDeinit(VOID)
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{
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UINT32 ret;
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@ -165,7 +227,7 @@ UINT32 ShmDeinit(VOID)
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return 0;
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}
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///给共享段中所有物理页框贴上共享标签
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STATIC inline VOID ShmSetSharedFlag(struct shmIDSource *seg)
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{
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LosVmPage *page = NULL;
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@ -174,7 +236,7 @@ STATIC inline VOID ShmSetSharedFlag(struct shmIDSource *seg)
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OsSetPageShared(page);
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}
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}
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///给共享段中所有物理页框撕掉共享标签
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STATIC inline VOID ShmClearSharedFlag(struct shmIDSource *seg)
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{
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LosVmPage *page = NULL;
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@ -183,7 +245,7 @@ STATIC inline VOID ShmClearSharedFlag(struct shmIDSource *seg)
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OsCleanPageShared(page);
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}
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}
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///seg下所有共享页引用减少
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STATIC VOID ShmPagesRefDec(struct shmIDSource *seg)
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{
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LosVmPage *page = NULL;
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@ -193,6 +255,15 @@ STATIC VOID ShmPagesRefDec(struct shmIDSource *seg)
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}
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}
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/**
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* @brief 为共享段分配物理内存
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例如:参数size = 4097, LOS_Align(size, PAGE_SIZE) = 8192
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分配页数 size >> PAGE_SHIFT = 2页
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* @param key
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* @param size
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* @param shmflg
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* @return STATIC
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*/
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STATIC INT32 ShmAllocSegCheck(key_t key, size_t *size, INT32 *segNum)
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{
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INT32 i;
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@ -201,7 +272,7 @@ STATIC INT32 ShmAllocSegCheck(key_t key, size_t *size, INT32 *segNum)
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return -EINVAL;
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}
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*size = LOS_Align(*size, PAGE_SIZE);
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*size = LOS_Align(*size, PAGE_SIZE);//必须对齐
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if ((IPC_SHM_USED_PAGE_COUNT + (*size >> PAGE_SHIFT)) > IPC_SHM_INFO.shmall) {
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return -ENOMEM;
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}
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@ -211,11 +282,10 @@ STATIC INT32 ShmAllocSegCheck(key_t key, size_t *size, INT32 *segNum)
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return -ENOMEM;
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}
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#endif
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for (i = 0; i < IPC_SHM_INFO.shmmni; i++) {
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if (IPC_SHM_SEGS[i].status & SHM_SEG_FREE) {
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IPC_SHM_SEGS[i].status &= ~SHM_SEG_FREE;
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*segNum = i;
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for (i = 0; i < IPC_SHM_INFO.shmmni; i++) {//试图找到一个空闲段与参数key绑定
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if (IPC_SHM_SEGS[i].status & SHM_SEG_FREE) {//找到空闲段
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IPC_SHM_SEGS[i].status &= ~SHM_SEG_FREE;//变成非空闲状态
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*segNum = i;//标号
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break;
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}
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}
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@ -236,49 +306,47 @@ STATIC INT32 ShmAllocSeg(key_t key, size_t size, INT32 shmflg)
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if (ret < 0) {
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return ret;
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}
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seg = &IPC_SHM_SEGS[segNum];
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count = LOS_PhysPagesAlloc(size >> PAGE_SHIFT, &seg->node);
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if (count != (size >> PAGE_SHIFT)) {
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(VOID)LOS_PhysPagesFree(&seg->node);
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seg->status = SHM_SEG_FREE;
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count = LOS_PhysPagesAlloc(size >> PAGE_SHIFT, &seg->node);//分配共享页面,函数内部把node都挂好了.
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if (count != (size >> PAGE_SHIFT)) {//当未分配到足够的内存时,处理方式是:不稀罕给那么点,舍弃!
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(VOID)LOS_PhysPagesFree(&seg->node);//释放节点上的物理页框
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seg->status = SHM_SEG_FREE;//共享段变回空闲状态
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#ifdef LOSCFG_KERNEL_IPC_PLIMIT
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OsIPCLimitShmFree(size);
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#endif
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return -ENOMEM;
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}
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ShmSetSharedFlag(seg);
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ShmSetSharedFlag(seg);//将node的每个页面设置为共享页
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IPC_SHM_USED_PAGE_COUNT += size >> PAGE_SHIFT;
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seg->status |= SHM_SEG_USED;
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seg->status |= SHM_SEG_USED; //共享段贴上已在使用的标签
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seg->ds.shm_perm.mode = (UINT32)shmflg & ACCESSPERMS;
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|
seg->ds.shm_perm.key = key;
|
|
|
|
|
seg->ds.shm_segsz = size;
|
|
|
|
|
seg->ds.shm_perm.cuid = LOS_GetUserID();
|
|
|
|
|
seg->ds.shm_perm.uid = LOS_GetUserID();
|
|
|
|
|
seg->ds.shm_perm.cgid = LOS_GetGroupID();
|
|
|
|
|
seg->ds.shm_perm.gid = LOS_GetGroupID();
|
|
|
|
|
seg->ds.shm_lpid = 0;
|
|
|
|
|
seg->ds.shm_nattch = 0;
|
|
|
|
|
seg->ds.shm_cpid = LOS_GetCurrProcessID();
|
|
|
|
|
seg->ds.shm_atime = 0;
|
|
|
|
|
seg->ds.shm_dtime = 0;
|
|
|
|
|
seg->ds.shm_ctime = time(NULL);
|
|
|
|
|
seg->ds.shm_perm.key = key;//保存参数key,如此 key 和 共享ID绑定在一块
|
|
|
|
|
seg->ds.shm_segsz = size; //共享段的大小
|
|
|
|
|
seg->ds.shm_perm.cuid = LOS_GetUserID(); //设置用户ID
|
|
|
|
|
seg->ds.shm_perm.uid = LOS_GetUserID(); //设置用户ID
|
|
|
|
|
seg->ds.shm_perm.cgid = LOS_GetGroupID(); //设置组ID
|
|
|
|
|
seg->ds.shm_perm.gid = LOS_GetGroupID(); //设置组ID
|
|
|
|
|
seg->ds.shm_lpid = 0; //最后一个操作的进程
|
|
|
|
|
seg->ds.shm_nattch = 0; //绑定进程的数量
|
|
|
|
|
seg->ds.shm_cpid = LOS_GetCurrProcessID(); //获取进程ID
|
|
|
|
|
seg->ds.shm_atime = 0; //访问时间
|
|
|
|
|
seg->ds.shm_dtime = 0; //detach 分离时间 共享内存使用完之后，需要将它从进程地址空间中分离出来；将共享内存分离并不是删除它，只是使该共享内存对当前的进程不再可用
|
|
|
|
|
seg->ds.shm_ctime = time(NULL);//创建时间
|
|
|
|
|
#ifdef LOSCFG_SHELL
|
|
|
|
|
(VOID)memcpy_s(seg->ownerName, OS_PCB_NAME_LEN, OsCurrProcessGet()->processName, OS_PCB_NAME_LEN);
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
return segNum;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///释放seg->node 所占物理页框,seg本身重置
|
|
|
|
|
STATIC INLINE VOID ShmFreeSeg(struct shmIDSource *seg, UINT32 *shmUsedPageCount)
|
|
|
|
|
{
|
|
|
|
|
UINT32 count;
|
|
|
|
|
|
|
|
|
|
ShmClearSharedFlag(seg);
|
|
|
|
|
count = LOS_PhysPagesFree(&seg->node);
|
|
|
|
|
if (count != (seg->ds.shm_segsz >> PAGE_SHIFT)) {
|
|
|
|
|
ShmClearSharedFlag(seg);//先撕掉 seg->node 中vmpage的共享标签
|
|
|
|
|
count = LOS_PhysPagesFree(&seg->node);//再挨个删除物理页框
|
|
|
|
|
if (count != (seg->ds.shm_segsz >> PAGE_SHIFT)) {//异常,必须要一样
|
|
|
|
|
VM_ERR("free physical pages failed, count = %d, size = %d", count, seg->ds.shm_segsz >> PAGE_SHIFT);
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
@ -288,31 +356,31 @@ STATIC INLINE VOID ShmFreeSeg(struct shmIDSource *seg, UINT32 *shmUsedPageCount)
|
|
|
|
|
if (shmUsedPageCount != NULL) {
|
|
|
|
|
(*shmUsedPageCount) -= seg->ds.shm_segsz >> PAGE_SHIFT;
|
|
|
|
|
}
|
|
|
|
|
seg->status = SHM_SEG_FREE;
|
|
|
|
|
LOS_ListInit(&seg->node);
|
|
|
|
|
seg->status = SHM_SEG_FREE;//seg恢复自由之身
|
|
|
|
|
LOS_ListInit(&seg->node);//重置node
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///通过key查找 shmId
|
|
|
|
|
STATIC INT32 ShmFindSegByKey(key_t key)
|
|
|
|
|
{
|
|
|
|
|
INT32 i;
|
|
|
|
|
struct shmIDSource *seg = NULL;
|
|
|
|
|
|
|
|
|
|
for (i = 0; i < IPC_SHM_INFO.shmmni; i++) {
|
|
|
|
|
for (i = 0; i < IPC_SHM_INFO.shmmni; i++) {//遍历共享段池,找到与key绑定的共享ID
|
|
|
|
|
seg = &IPC_SHM_SEGS[i];
|
|
|
|
|
if ((seg->status & SHM_SEG_USED) &&
|
|
|
|
|
(seg->ds.shm_perm.key == key)) {
|
|
|
|
|
(seg->ds.shm_perm.key == key)) {//满足两个条件,找到后返回
|
|
|
|
|
return i;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
return -1;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///共享内存段有效性检查
|
|
|
|
|
STATIC INT32 ShmSegValidCheck(INT32 segNum, size_t size, INT32 shmFlg)
|
|
|
|
|
{
|
|
|
|
|
struct shmIDSource *seg = &IPC_SHM_SEGS[segNum];
|
|
|
|
|
struct shmIDSource *seg = &IPC_SHM_SEGS[segNum];//拿到shmID
|
|
|
|
|
|
|
|
|
|
if (size > seg->ds.shm_segsz) {
|
|
|
|
|
if (size > seg->ds.shm_segsz) {//段长
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
@ -323,7 +391,7 @@ STATIC INT32 ShmSegValidCheck(INT32 segNum, size_t size, INT32 shmFlg)
|
|
|
|
|
|
|
|
|
|
return segNum;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///通过ID找到共享内存资源
|
|
|
|
|
STATIC struct shmIDSource *ShmFindSeg(int shmid)
|
|
|
|
|
{
|
|
|
|
|
struct shmIDSource *seg = NULL;
|
|
|
|
|
@ -341,7 +409,7 @@ STATIC struct shmIDSource *ShmFindSeg(int shmid)
|
|
|
|
|
|
|
|
|
|
return seg;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///共享内存映射
|
|
|
|
|
STATIC VOID ShmVmmMapping(LosVmSpace *space, LOS_DL_LIST *pageList, VADDR_T vaddr, UINT32 regionFlags)
|
|
|
|
|
{
|
|
|
|
|
LosVmPage *vmPage = NULL;
|
|
|
|
|
@ -349,64 +417,64 @@ STATIC VOID ShmVmmMapping(LosVmSpace *space, LOS_DL_LIST *pageList, VADDR_T vadd
|
|
|
|
|
PADDR_T pa;
|
|
|
|
|
STATUS_T ret;
|
|
|
|
|
|
|
|
|
|
LOS_DL_LIST_FOR_EACH_ENTRY(vmPage, pageList, LosVmPage, node) {
|
|
|
|
|
pa = VM_PAGE_TO_PHYS(vmPage);
|
|
|
|
|
LOS_AtomicInc(&vmPage->refCounts);
|
|
|
|
|
ret = LOS_ArchMmuMap(&space->archMmu, va, pa, 1, regionFlags);
|
|
|
|
|
LOS_DL_LIST_FOR_EACH_ENTRY(vmPage, pageList, LosVmPage, node) {//遍历一页一页映射
|
|
|
|
|
pa = VM_PAGE_TO_PHYS(vmPage);//拿到物理地址
|
|
|
|
|
LOS_AtomicInc(&vmPage->refCounts);//自增
|
|
|
|
|
ret = LOS_ArchMmuMap(&space->archMmu, va, pa, 1, regionFlags);//虚实映射
|
|
|
|
|
if (ret != 1) {
|
|
|
|
|
VM_ERR("LOS_ArchMmuMap failed, ret = %d", ret);
|
|
|
|
|
}
|
|
|
|
|
va += PAGE_SIZE;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///fork 一个共享线性区
|
|
|
|
|
VOID OsShmFork(LosVmSpace *space, LosVmMapRegion *oldRegion, LosVmMapRegion *newRegion)
|
|
|
|
|
{
|
|
|
|
|
struct shmIDSource *seg = NULL;
|
|
|
|
|
|
|
|
|
|
SYSV_SHM_LOCK();
|
|
|
|
|
seg = ShmFindSeg(oldRegion->shmid);
|
|
|
|
|
seg = ShmFindSeg(oldRegion->shmid);//通过老区ID获取对应的共享资源ID结构体
|
|
|
|
|
if (seg == NULL) {
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
VM_ERR("shm fork failed!");
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
newRegion->shmid = oldRegion->shmid;
|
|
|
|
|
newRegion->forkFlags = oldRegion->forkFlags;
|
|
|
|
|
ShmVmmMapping(space, &seg->node, newRegion->range.base, newRegion->regionFlags);
|
|
|
|
|
seg->ds.shm_nattch++;
|
|
|
|
|
newRegion->shmid = oldRegion->shmid;//一样的共享区ID
|
|
|
|
|
newRegion->forkFlags = oldRegion->forkFlags;//forkFlags也一样了
|
|
|
|
|
ShmVmmMapping(space, &seg->node, newRegion->range.base, newRegion->regionFlags);//新线性区与共享内存进行映射
|
|
|
|
|
seg->ds.shm_nattch++;//附在共享线性区上的进程数++
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///释放共享线性区
|
|
|
|
|
VOID OsShmRegionFree(LosVmSpace *space, LosVmMapRegion *region)
|
|
|
|
|
{
|
|
|
|
|
struct shmIDSource *seg = NULL;
|
|
|
|
|
|
|
|
|
|
SYSV_SHM_LOCK();
|
|
|
|
|
seg = ShmFindSeg(region->shmid);
|
|
|
|
|
seg = ShmFindSeg(region->shmid);//通过线性区ID获取对应的共享资源ID结构体
|
|
|
|
|
if (seg == NULL) {
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
return;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
LOS_ArchMmuUnmap(&space->archMmu, region->range.base, region->range.size >> PAGE_SHIFT);
|
|
|
|
|
ShmPagesRefDec(seg);
|
|
|
|
|
seg->ds.shm_nattch--;
|
|
|
|
|
LOS_ArchMmuUnmap(&space->archMmu, region->range.base, region->range.size >> PAGE_SHIFT);//解除线性区的映射
|
|
|
|
|
ShmPagesRefDec(seg);//ref --
|
|
|
|
|
seg->ds.shm_nattch--;//附在共享线性区上的进程数--
|
|
|
|
|
if (seg->ds.shm_nattch <= 0 && (seg->status & SHM_SEG_REMOVE)) {
|
|
|
|
|
ShmFreeSeg(seg, &IPC_SHM_USED_PAGE_COUNT);
|
|
|
|
|
ShmFreeSeg(seg, &IPC_SHM_USED_PAGE_COUNT);//就释放掉物理内存!注意是:物理内存
|
|
|
|
|
} else {
|
|
|
|
|
seg->ds.shm_dtime = time(NULL);
|
|
|
|
|
seg->ds.shm_lpid = LOS_GetCurrProcessID(); /* may not be the space's PID. */
|
|
|
|
|
}
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///是否为共享线性区,是否有标签?
|
|
|
|
|
BOOL OsIsShmRegion(LosVmMapRegion *region)
|
|
|
|
|
{
|
|
|
|
|
return (region->regionFlags & VM_MAP_REGION_FLAG_SHM) ? TRUE : FALSE;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///获取共享内存池中已被使用的段数量
|
|
|
|
|
STATIC INT32 ShmSegUsedCount(VOID)
|
|
|
|
|
{
|
|
|
|
|
INT32 i;
|
|
|
|
|
@ -415,16 +483,16 @@ STATIC INT32 ShmSegUsedCount(VOID)
|
|
|
|
|
|
|
|
|
|
for (i = 0; i < IPC_SHM_INFO.shmmni; i++) {
|
|
|
|
|
seg = &IPC_SHM_SEGS[i];
|
|
|
|
|
if (seg->status & SHM_SEG_USED) {
|
|
|
|
|
if (seg->status & SHM_SEG_USED) {//找到一个
|
|
|
|
|
count++;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
return count;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///对共享内存段权限检查
|
|
|
|
|
STATIC INT32 ShmPermCheck(struct shmIDSource *seg, mode_t mode)
|
|
|
|
|
{
|
|
|
|
|
INT32 uid = LOS_GetUserID();
|
|
|
|
|
INT32 uid = LOS_GetUserID();//当前进程的用户ID
|
|
|
|
|
UINT32 tmpMode = 0;
|
|
|
|
|
mode_t privMode = seg->ds.shm_perm.mode;
|
|
|
|
|
mode_t accMode;
|
|
|
|
|
@ -466,6 +534,22 @@ STATIC INT32 ShmPermCheck(struct shmIDSource *seg, mode_t mode)
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*!
|
|
|
|
|
* @brief ShmGet
|
|
|
|
|
* 得到一个共享内存标识符或创建一个共享内存对象
|
|
|
|
|
* @param key 建立新共享内存对象 标识符是IPC对象的内部名。为使多个合作进程能够在同一IPC对象上汇聚，需要提供一个外部命名方案。
|
|
|
|
|
为此，每个IPC对象都与一个键（key）相关联，这个键作为该对象的外部名,无论何时创建IPC结构（通过msgget、semget、shmget创建），
|
|
|
|
|
都应给IPC指定一个键, key_t由ftok创建,ftok当然在本工程里找不到,所以要写这么多.
|
|
|
|
|
* @param shmflg IPC_CREAT IPC_EXCL
|
|
|
|
|
IPC_CREAT： 在创建新的IPC时，如果key参数是IPC_PRIVATE或者和当前某种类型的IPC结构无关，则需要指明flag参数的IPC_CREAT标志位，
|
|
|
|
|
则用来创建一个新的IPC结构。（如果IPC结构已存在，并且指定了IPC_CREAT，则IPC_CREAT什么都不做，函数也不出错）
|
|
|
|
|
IPC_EXCL： 此参数一般与IPC_CREAT配合使用来创建一个新的IPC结构。如果创建的IPC结构已存在函数就出错返回，
|
|
|
|
|
返回EEXIST（这与open函数指定O_CREAT和O_EXCL标志原理相同）
|
|
|
|
|
* @param size 新建的共享内存大小，以字节为单位
|
|
|
|
|
* @return
|
|
|
|
|
*
|
|
|
|
|
* @see
|
|
|
|
|
*/
|
|
|
|
|
INT32 ShmGet(key_t key, size_t size, INT32 shmflg)
|
|
|
|
|
{
|
|
|
|
|
INT32 ret;
|
|
|
|
|
@ -476,13 +560,13 @@ INT32 ShmGet(key_t key, size_t size, INT32 shmflg)
|
|
|
|
|
if (key == IPC_PRIVATE) {
|
|
|
|
|
ret = ShmAllocSeg(key, size, shmflg);
|
|
|
|
|
} else {
|
|
|
|
|
ret = ShmFindSegByKey(key);
|
|
|
|
|
ret = ShmFindSegByKey(key);//通过key查找资源ID
|
|
|
|
|
if (ret < 0) {
|
|
|
|
|
if (((UINT32)shmflg & IPC_CREAT) == 0) {
|
|
|
|
|
if (((UINT32)shmflg & IPC_CREAT) == 0) {//
|
|
|
|
|
ret = -ENOENT;
|
|
|
|
|
goto ERROR;
|
|
|
|
|
} else {
|
|
|
|
|
ret = ShmAllocSeg(key, size, shmflg);
|
|
|
|
|
ret = ShmAllocSeg(key, size, shmflg);//分配一个共享内存
|
|
|
|
|
}
|
|
|
|
|
} else {
|
|
|
|
|
shmid = ret;
|
|
|
|
|
@ -491,7 +575,7 @@ INT32 ShmGet(key_t key, size_t size, INT32 shmflg)
|
|
|
|
|
ret = -EEXIST;
|
|
|
|
|
goto ERROR;
|
|
|
|
|
}
|
|
|
|
|
ret = ShmPermCheck(ShmFindSeg(shmid), (UINT32)shmflg & ACCESSPERMS);
|
|
|
|
|
ret = ShmPermCheck(ShmFindSeg(shmid), (UINT32)shmflg & ACCESSPERMS);//对共享内存权限检查
|
|
|
|
|
if (ret != 0) {
|
|
|
|
|
ret = -ret;
|
|
|
|
|
goto ERROR;
|
|
|
|
|
@ -526,13 +610,13 @@ INT32 ShmatParamCheck(const VOID *shmaddr, INT32 shmflg)
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///分配一个共享线性区并映射好
|
|
|
|
|
LosVmMapRegion *ShmatVmmAlloc(struct shmIDSource *seg, const VOID *shmaddr,
|
|
|
|
|
INT32 shmflg, UINT32 prot)
|
|
|
|
|
{
|
|
|
|
|
LosVmSpace *space = OsCurrProcessGet()->vmSpace;
|
|
|
|
|
LosVmMapRegion *region = NULL;
|
|
|
|
|
UINT32 flags = MAP_ANONYMOUS | MAP_SHARED;
|
|
|
|
|
UINT32 flags = MAP_ANONYMOUS | MAP_SHARED;//本线性区为共享+匿名标签
|
|
|
|
|
UINT32 mapFlags = flags | MAP_FIXED;
|
|
|
|
|
VADDR_T vaddr;
|
|
|
|
|
UINT32 regionFlags;
|
|
|
|
|
@ -543,29 +627,29 @@ LosVmMapRegion *ShmatVmmAlloc(struct shmIDSource *seg, const VOID *shmaddr,
|
|
|
|
|
}
|
|
|
|
|
regionFlags = OsCvtProtFlagsToRegionFlags(prot, flags);
|
|
|
|
|
(VOID)LOS_MuxAcquire(&space->regionMux);
|
|
|
|
|
if (shmaddr == NULL) {
|
|
|
|
|
region = LOS_RegionAlloc(space, 0, seg->ds.shm_segsz, regionFlags, 0);
|
|
|
|
|
} else {
|
|
|
|
|
if (shmaddr == NULL) {//未指定了共享内存连接到当前进程中的地址位置
|
|
|
|
|
region = LOS_RegionAlloc(space, 0, seg->ds.shm_segsz, regionFlags, 0);//分配线性区
|
|
|
|
|
} else {//指定时,就需要先找地址所在的线性区
|
|
|
|
|
if ((UINT32)shmflg & SHM_RND) {
|
|
|
|
|
vaddr = ROUNDDOWN((VADDR_T)(UINTPTR)shmaddr, SHMLBA);
|
|
|
|
|
} else {
|
|
|
|
|
vaddr = (VADDR_T)(UINTPTR)shmaddr;
|
|
|
|
|
}
|
|
|
|
|
}//找到线性区并重新映射,当指定地址时需贴上重新映射的标签
|
|
|
|
|
if (!((UINT32)shmflg & SHM_REMAP) && (LOS_RegionFind(space, vaddr) ||
|
|
|
|
|
LOS_RegionFind(space, vaddr + seg->ds.shm_segsz - 1) ||
|
|
|
|
|
LOS_RegionRangeFind(space, vaddr, seg->ds.shm_segsz - 1))) {
|
|
|
|
|
ret = EINVAL;
|
|
|
|
|
goto ERROR;
|
|
|
|
|
}
|
|
|
|
|
vaddr = (VADDR_T)LOS_MMap(vaddr, seg->ds.shm_segsz, prot, mapFlags, -1, 0);
|
|
|
|
|
region = LOS_RegionFind(space, vaddr);
|
|
|
|
|
vaddr = (VADDR_T)LOS_MMap(vaddr, seg->ds.shm_segsz, prot, mapFlags, -1, 0);//做好映射
|
|
|
|
|
region = LOS_RegionFind(space, vaddr);//重新查找线性区,用于返回.
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if (region == NULL) {
|
|
|
|
|
ret = ENOMEM;
|
|
|
|
|
goto ERROR;
|
|
|
|
|
}
|
|
|
|
|
ShmVmmMapping(space, &seg->node, region->range.base, regionFlags);
|
|
|
|
|
ShmVmmMapping(space, &seg->node, region->range.base, regionFlags);//共享内存映射
|
|
|
|
|
(VOID)LOS_MuxRelease(&space->regionMux);
|
|
|
|
|
return region;
|
|
|
|
|
ERROR:
|
|
|
|
|
@ -574,6 +658,17 @@ ERROR:
|
|
|
|
|
return NULL;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*!
|
|
|
|
|
* @brief ShmAt
|
|
|
|
|
* 用来启动对该共享内存的访问，并把共享内存连接到当前进程的地址空间。
|
|
|
|
|
* @param shm_flg 是一组标志位，通常为0。
|
|
|
|
|
* @param shmaddr 指定共享内存连接到当前进程中的地址位置，通常为空，表示让系统来选择共享内存的地址。
|
|
|
|
|
* @param shmid 是shmget()函数返回的共享内存标识符
|
|
|
|
|
* @return
|
|
|
|
|
* 如果shmat成功执行，那么内核将使与该共享存储相关的shmid_ds结构中的shm_nattch计数器值加1
|
|
|
|
|
shmid 就是个索引,就跟进程和线程的ID一样 g_shmSegs[shmid] shmid > 192个
|
|
|
|
|
* @see
|
|
|
|
|
*/
|
|
|
|
|
VOID *ShmAt(INT32 shmid, const VOID *shmaddr, INT32 shmflg)
|
|
|
|
|
{
|
|
|
|
|
INT32 ret;
|
|
|
|
|
@ -582,13 +677,13 @@ VOID *ShmAt(INT32 shmid, const VOID *shmaddr, INT32 shmflg)
|
|
|
|
|
struct shmIDSource *seg = NULL;
|
|
|
|
|
LosVmMapRegion *r = NULL;
|
|
|
|
|
|
|
|
|
|
ret = ShmatParamCheck(shmaddr, shmflg);
|
|
|
|
|
ret = ShmatParamCheck(shmaddr, shmflg);//参数检查
|
|
|
|
|
if (ret != 0) {
|
|
|
|
|
set_errno(ret);
|
|
|
|
|
return (VOID *)-1;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
if ((UINT32)shmflg & SHM_EXEC) {
|
|
|
|
|
if ((UINT32)shmflg & SHM_EXEC) {//flag 转换
|
|
|
|
|
prot |= PROT_EXEC;
|
|
|
|
|
acc_mode |= SHM_S_IXUGO;
|
|
|
|
|
} else if (((UINT32)shmflg & SHM_RDONLY) == 0) {
|
|
|
|
|
@ -597,7 +692,7 @@ VOID *ShmAt(INT32 shmid, const VOID *shmaddr, INT32 shmflg)
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
SYSV_SHM_LOCK();
|
|
|
|
|
seg = ShmFindSeg(shmid);
|
|
|
|
|
seg = ShmFindSeg(shmid);//找到段
|
|
|
|
|
if (seg == NULL) {
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
return (VOID *)-1;
|
|
|
|
|
@ -608,18 +703,18 @@ VOID *ShmAt(INT32 shmid, const VOID *shmaddr, INT32 shmflg)
|
|
|
|
|
goto ERROR;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
seg->ds.shm_nattch++;
|
|
|
|
|
r = ShmatVmmAlloc(seg, shmaddr, shmflg, prot);
|
|
|
|
|
seg->ds.shm_nattch++;//ds上记录有一个进程绑定上来
|
|
|
|
|
r = ShmatVmmAlloc(seg, shmaddr, shmflg, prot);//在当前进程空间分配一个线性区并映射到共享内存
|
|
|
|
|
if (r == NULL) {
|
|
|
|
|
seg->ds.shm_nattch--;
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
return (VOID *)-1;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
r->shmid = shmid;
|
|
|
|
|
r->regionFlags |= VM_MAP_REGION_FLAG_SHM;
|
|
|
|
|
seg->ds.shm_atime = time(NULL);
|
|
|
|
|
seg->ds.shm_lpid = LOS_GetCurrProcessID();
|
|
|
|
|
r->shmid = shmid;//把ID给线性区的shmid
|
|
|
|
|
r->regionFlags |= VM_MAP_REGION_FLAG_SHM;//这是一个共享线性区
|
|
|
|
|
seg->ds.shm_atime = time(NULL);//访问时间
|
|
|
|
|
seg->ds.shm_lpid = LOS_GetCurrProcessID();//进程ID
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
|
|
|
|
|
return (VOID *)(UINTPTR)r->range.base;
|
|
|
|
|
@ -630,6 +725,19 @@ ERROR:
|
|
|
|
|
return (VOID *)-1;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*!
|
|
|
|
|
* @brief ShmCtl
|
|
|
|
|
* 此函数可以对shmid指定的共享存储进行多种操作（删除、取信息、加锁、解锁等）
|
|
|
|
|
* @param buf 是一个结构指针，它指向共享内存模式和访问权限的结构。
|
|
|
|
|
* @param cmd command是要采取的操作，它可以取下面的三个值 ：
|
|
|
|
|
IPC_STAT：把shmid_ds结构中的数据设置为共享内存的当前关联值，即用共享内存的当前关联值覆盖shmid_ds的值。
|
|
|
|
|
IPC_SET：如果进程有足够的权限，就把共享内存的当前关联值设置为shmid_ds结构中给出的值
|
|
|
|
|
IPC_RMID：删除共享内存段
|
|
|
|
|
* @param shmid 是shmget()函数返回的共享内存标识符
|
|
|
|
|
* @return
|
|
|
|
|
*
|
|
|
|
|
* @see
|
|
|
|
|
*/
|
|
|
|
|
INT32 ShmCtl(INT32 shmid, INT32 cmd, struct shmid_ds *buf)
|
|
|
|
|
{
|
|
|
|
|
struct shmIDSource *seg = NULL;
|
|
|
|
|
@ -642,7 +750,7 @@ INT32 ShmCtl(INT32 shmid, INT32 cmd, struct shmid_ds *buf)
|
|
|
|
|
SYSV_SHM_LOCK();
|
|
|
|
|
|
|
|
|
|
if ((cmd != IPC_INFO) && (cmd != SHM_INFO)) {
|
|
|
|
|
seg = ShmFindSeg(shmid);
|
|
|
|
|
seg = ShmFindSeg(shmid);//通过索引ID找到seg
|
|
|
|
|
if (seg == NULL) {
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
return -1;
|
|
|
|
|
@ -656,13 +764,13 @@ INT32 ShmCtl(INT32 shmid, INT32 cmd, struct shmid_ds *buf)
|
|
|
|
|
|
|
|
|
|
switch (cmd) {
|
|
|
|
|
case IPC_STAT:
|
|
|
|
|
case SHM_STAT:
|
|
|
|
|
case SHM_STAT://取段结构
|
|
|
|
|
ret = ShmPermCheck(seg, SHM_S_IRUGO);
|
|
|
|
|
if (ret != 0) {
|
|
|
|
|
goto ERROR;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
ret = LOS_ArchCopyToUser(buf, &seg->ds, sizeof(struct shmid_ds));
|
|
|
|
|
ret = LOS_ArchCopyToUser(buf, &seg->ds, sizeof(struct shmid_ds));//把内核空间的共享页数据拷贝到用户空间
|
|
|
|
|
if (ret != 0) {
|
|
|
|
|
ret = EFAULT;
|
|
|
|
|
goto ERROR;
|
|
|
|
|
@ -671,13 +779,13 @@ INT32 ShmCtl(INT32 shmid, INT32 cmd, struct shmid_ds *buf)
|
|
|
|
|
ret = (unsigned int)((unsigned int)seg->ds.shm_perm.seq << 16) | (unsigned int)((unsigned int)shmid & 0xffff); /* 16: use the seq as the upper 16 bits */
|
|
|
|
|
}
|
|
|
|
|
break;
|
|
|
|
|
case IPC_SET:
|
|
|
|
|
case IPC_SET://重置共享段
|
|
|
|
|
ret = ShmPermCheck(seg, SHM_M);
|
|
|
|
|
if (ret != 0) {
|
|
|
|
|
ret = EPERM;
|
|
|
|
|
goto ERROR;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
//从用户空间拷贝数据到内核空间
|
|
|
|
|
ret = LOS_ArchCopyFromUser(&shm_perm, &buf->shm_perm, sizeof(struct ipc_perm));
|
|
|
|
|
if (ret != 0) {
|
|
|
|
|
ret = EFAULT;
|
|
|
|
|
@ -686,14 +794,14 @@ INT32 ShmCtl(INT32 shmid, INT32 cmd, struct shmid_ds *buf)
|
|
|
|
|
seg->ds.shm_perm.uid = shm_perm.uid;
|
|
|
|
|
seg->ds.shm_perm.gid = shm_perm.gid;
|
|
|
|
|
seg->ds.shm_perm.mode = (seg->ds.shm_perm.mode & ~ACCESSPERMS) |
|
|
|
|
|
(shm_perm.mode & ACCESSPERMS);
|
|
|
|
|
(shm_perm.mode & ACCESSPERMS);//可访问
|
|
|
|
|
seg->ds.shm_ctime = time(NULL);
|
|
|
|
|
#ifdef LOSCFG_SHELL
|
|
|
|
|
(VOID)memcpy_s(seg->ownerName, OS_PCB_NAME_LEN, OS_PCB_FROM_PID(shm_perm.uid)->processName,
|
|
|
|
|
OS_PCB_NAME_LEN);
|
|
|
|
|
#endif
|
|
|
|
|
break;
|
|
|
|
|
case IPC_RMID:
|
|
|
|
|
case IPC_RMID://删除共享段
|
|
|
|
|
ret = ShmPermCheck(seg, SHM_M);
|
|
|
|
|
if (ret != 0) {
|
|
|
|
|
ret = EPERM;
|
|
|
|
|
@ -701,11 +809,11 @@ INT32 ShmCtl(INT32 shmid, INT32 cmd, struct shmid_ds *buf)
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
seg->status |= SHM_SEG_REMOVE;
|
|
|
|
|
if (seg->ds.shm_nattch <= 0) {
|
|
|
|
|
if (seg->ds.shm_nattch <= 0) {//没有任何进程在使用了
|
|
|
|
|
ShmFreeSeg(seg, &IPC_SHM_USED_PAGE_COUNT);
|
|
|
|
|
}
|
|
|
|
|
break;
|
|
|
|
|
case IPC_INFO:
|
|
|
|
|
case IPC_INFO://把内核空间的共享页数据拷贝到用户空间
|
|
|
|
|
ret = LOS_ArchCopyToUser(buf, &IPC_SHM_INFO, sizeof(struct shminfo));
|
|
|
|
|
if (ret != 0) {
|
|
|
|
|
ret = EFAULT;
|
|
|
|
|
@ -719,8 +827,8 @@ INT32 ShmCtl(INT32 shmid, INT32 cmd, struct shmid_ds *buf)
|
|
|
|
|
shmInfo.shm_tot = 0;
|
|
|
|
|
shmInfo.swap_attempts = 0;
|
|
|
|
|
shmInfo.swap_successes = 0;
|
|
|
|
|
shmInfo.used_ids = ShmSegUsedCount();
|
|
|
|
|
ret = LOS_ArchCopyToUser(buf, &shmInfo, sizeof(struct shm_info));
|
|
|
|
|
shmInfo.used_ids = ShmSegUsedCount();//在使用的seg数
|
|
|
|
|
ret = LOS_ArchCopyToUser(buf, &shmInfo, sizeof(struct shm_info));//把内核空间的共享页数据拷贝到用户空间
|
|
|
|
|
if (ret != 0) {
|
|
|
|
|
ret = EFAULT;
|
|
|
|
|
goto ERROR;
|
|
|
|
|
@ -743,55 +851,63 @@ ERROR:
|
|
|
|
|
return -1;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/**
|
|
|
|
|
* @brief 当对共享存储的操作已经结束时，则调用shmdt与该存储段分离
|
|
|
|
|
如果shmat成功执行，那么内核将使与该共享存储相关的shmid_ds结构中的shm_nattch计数器值减1
|
|
|
|
|
* @attention 注意：这并不从系统中删除共享存储的标识符以及其相关的数据结构。共享存储的仍然存在，
|
|
|
|
|
直至某个进程带IPC_RMID命令的调用shmctl特地删除共享存储为止
|
|
|
|
|
* @param shmaddr
|
|
|
|
|
* @return INT32
|
|
|
|
|
*/
|
|
|
|
|
INT32 ShmDt(const VOID *shmaddr)
|
|
|
|
|
{
|
|
|
|
|
LosVmSpace *space = OsCurrProcessGet()->vmSpace;
|
|
|
|
|
LosVmSpace *space = OsCurrProcessGet()->vmSpace;//获取进程空间
|
|
|
|
|
struct shmIDSource *seg = NULL;
|
|
|
|
|
LosVmMapRegion *region = NULL;
|
|
|
|
|
INT32 shmid;
|
|
|
|
|
INT32 ret;
|
|
|
|
|
|
|
|
|
|
if (IS_PAGE_ALIGNED(shmaddr) == 0) {
|
|
|
|
|
if (IS_PAGE_ALIGNED(shmaddr) == 0) {//地址是否对齐
|
|
|
|
|
ret = EINVAL;
|
|
|
|
|
goto ERROR;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
(VOID)LOS_MuxAcquire(&space->regionMux);
|
|
|
|
|
region = LOS_RegionFind(space, (VADDR_T)(UINTPTR)shmaddr);
|
|
|
|
|
region = LOS_RegionFind(space, (VADDR_T)(UINTPTR)shmaddr);//找到线性区
|
|
|
|
|
if (region == NULL) {
|
|
|
|
|
ret = EINVAL;
|
|
|
|
|
goto ERROR_WITH_LOCK;
|
|
|
|
|
}
|
|
|
|
|
shmid = region->shmid;
|
|
|
|
|
shmid = region->shmid;//线性区共享ID
|
|
|
|
|
|
|
|
|
|
if (region->range.base != (VADDR_T)(UINTPTR)shmaddr) {
|
|
|
|
|
ret = EINVAL;
|
|
|
|
|
if (region->range.base != (VADDR_T)(UINTPTR)shmaddr) {//这是用户空间和内核空间的一次解绑
|
|
|
|
|
ret = EINVAL; //shmaddr 必须要等于region->range.base
|
|
|
|
|
goto ERROR_WITH_LOCK;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* remove it from aspace */
|
|
|
|
|
LOS_RbDelNode(&space->regionRbTree, ®ion->rbNode);
|
|
|
|
|
LOS_ArchMmuUnmap(&space->archMmu, region->range.base, region->range.size >> PAGE_SHIFT);
|
|
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|
|
LOS_RbDelNode(&space->regionRbTree, ®ion->rbNode);//从红黑树和链表中摘除节点
|
|
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|
|
LOS_ArchMmuUnmap(&space->archMmu, region->range.base, region->range.size >> PAGE_SHIFT);//解除线性区的映射
|
|
|
|
|
(VOID)LOS_MuxRelease(&space->regionMux);
|
|
|
|
|
/* free it */
|
|
|
|
|
free(region);
|
|
|
|
|
free(region);//释放线性区所占内存池中的内存
|
|
|
|
|
|
|
|
|
|
SYSV_SHM_LOCK();
|
|
|
|
|
seg = ShmFindSeg(shmid);
|
|
|
|
|
seg = ShmFindSeg(shmid);//找到seg,线性区和共享段的关系是 1:N 的关系,其他空间的线性区也会绑在共享段上
|
|
|
|
|
if (seg == NULL) {
|
|
|
|
|
ret = EINVAL;
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
goto ERROR;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
ShmPagesRefDec(seg);
|
|
|
|
|
seg->ds.shm_nattch--;
|
|
|
|
|
if ((seg->ds.shm_nattch <= 0) &&
|
|
|
|
|
(seg->status & SHM_SEG_REMOVE)) {
|
|
|
|
|
ShmFreeSeg(seg, &IPC_SHM_USED_PAGE_COUNT);
|
|
|
|
|
ShmPagesRefDec(seg);//页面引用数 --
|
|
|
|
|
seg->ds.shm_nattch--;//使用共享内存的进程数少了一个
|
|
|
|
|
if ((seg->ds.shm_nattch <= 0) && //无任何进程使用共享内存
|
|
|
|
|
(seg->status & SHM_SEG_REMOVE)) {//状态为删除时需要释放物理页内存了,否则其他进程还要继续使用共享内存
|
|
|
|
|
ShmFreeSeg(seg, &IPC_SHM_USED_PAGE_COUNT);//释放seg 页框链表中的页框内存,再重置seg状态
|
|
|
|
|
} else {
|
|
|
|
|
seg->ds.shm_dtime = time(NULL);
|
|
|
|
|
seg->ds.shm_lpid = LOS_GetCurrProcessID();
|
|
|
|
|
seg->ds.shm_dtime = time(NULL);//记录分离的时间
|
|
|
|
|
seg->ds.shm_lpid = LOS_GetCurrProcessID();//记录操作进程ID
|
|
|
|
|
}
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
|
|
|
|
|
@ -847,7 +963,6 @@ STATIC VOID OsShmInfoCmd(VOID)
|
|
|
|
|
}
|
|
|
|
|
SYSV_SHM_UNLOCK();
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
STATIC VOID OsShmDeleteCmd(INT32 shmid)
|
|
|
|
|
{
|
|
|
|
|
struct shmIDSource *seg = NULL;
|
|
|
|
|
@ -876,7 +991,7 @@ STATIC VOID OsShmCmdUsage(VOID)
|
|
|
|
|
"\t-r [shmid], Recycle the specified shared memory about shmid\n"
|
|
|
|
|
"\t-h | --help, print shm command usage\n");
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
///共享内存
|
|
|
|
|
UINT32 OsShellCmdShm(INT32 argc, const CHAR *argv[])
|
|
|
|
|
{
|
|
|
|
|
INT32 shmid;
|
|
|
|
|
@ -911,4 +1026,3 @@ DONE:
|
|
|
|
|
SHELLCMD_ENTRY(shm_shellcmd, CMD_TYPE_SHOW, "shm", 2, (CmdCallBackFunc)OsShellCmdShm);
|
|
|
|
|
#endif
|
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
|
Dio
m4l6qprxo
dancer