鸿蒙对 /proc 的实现很有意思,/proc被称为伪文件系统,或内存文件系统

    百万汉字注解 + 百篇博客分析 => 挖透鸿蒙内核源码
    国内:https://weharmony.21cloudbox.com
    国外:https://weharmony.github.io

fs/proc/include/proc_fs.h

@@ -88,13 +88,13 @@ struct ProcFileOperations {
 };
 //proc 目录/文件项, @notethinking 直接叫 ProcEntry不香吗 ?
 struct ProcDirEntry {
-    mode_t mode;
-    int flags;
-    const struct ProcFileOperations *procFileOps;
-    struct ProcFile *pf;
+    mode_t mode;	//模式(读|写...)
+    int flags;	//标签
+    const struct ProcFileOperations *procFileOps;//驱动程序
+    struct ProcFile *pf;//文件指针
     struct ProcDirEntry *next, *parent, *subdir;//当前目录项的关系项
     void *data;
-    atomic_t count; /* open file count */
+    atomic_t count; /* open file count */ //打开文件的数量
     spinlock_t pdeUnloadLock;
 
     int nameLen;

fs/proc/os_adapt/proc_vfs.c

@@ -41,8 +41,8 @@
 
 #define PROCFS_DEFAULT_MODE 0555
 
-#ifdef LOSCFG_FS_PROC
-static struct VnodeOps g_procfsVops;
+#ifdef LOSCFG_FS_PROC //使能 /proc 功能
+static struct VnodeOps g_procfsVops; // proc 文件系统
 static struct file_operations_vfs g_procfsFops;
 
 static struct ProcDirEntry *VnodeToEntry(struct Vnode *node)
@@ -177,7 +177,7 @@ int VfsProcfsLookup(struct Vnode *parent, const char *name, int len, struct Vnod
     (*vpp)->parent = parent;
     return LOS_OK;
 }
-
+//装载实现,将mount挂到vnode节点上 
 int VfsProcfsMount(struct Mount *mnt, struct Vnode *device, const void *data)
 {
     struct Vnode *vp = NULL;
@@ -193,7 +193,7 @@ int VfsProcfsMount(struct Mount *mnt, struct Vnode *device, const void *data)
 
     struct ProcDirEntry *root = GetProcRootEntry();
     vp->data = root;
-    vp->originMount = mnt;
+    vp->originMount = mnt;//绑定mount
     vp->fop = &g_procfsFops;
     mnt->data = NULL;
     mnt->vnodeCovered = vp;
@@ -272,7 +272,7 @@ int VfsProcfsReaddir(struct Vnode *node, struct fs_dirent_s *dir)
 
     return i;
 }
-
+//proc 打开目录
 int VfsProcfsOpendir(struct Vnode *node,  struct fs_dirent_s *dir)
 {
     struct ProcDirEntry *pde = VnodeToEntry(node);
@@ -284,7 +284,7 @@ int VfsProcfsOpendir(struct Vnode *node,  struct fs_dirent_s *dir)
 
     return LOS_OK;
 }
-
+//proc 打开文件
 int VfsProcfsOpen(struct file *filep)
 {
     if (filep == NULL) {
@@ -323,7 +323,7 @@ int VfsProcfsClose(struct file *filep)
 
     return result;
 }
-
+//统计信息接口,简单实现
 int VfsProcfsStatfs(struct Mount *mnt, struct statfs *buf)
 {
     (void)memset_s(buf, sizeof(struct statfs), 0, sizeof(struct statfs));
@@ -336,14 +336,14 @@ int VfsProcfsClosedir(struct Vnode *vp, struct fs_dirent_s *dir)
 {
     return LOS_OK;
 }
-
+// proc 对 MountOps 接口实现
 const struct MountOps procfs_operations = {
-    .Mount = VfsProcfsMount,
+    .Mount = VfsProcfsMount,//装载
     .Unmount = NULL,
-    .Statfs = VfsProcfsStatfs,
+    .Statfs = VfsProcfsStatfs,//统计信息
 };
-
-static struct VnodeOps g_procfsVops = {
+// proc 对 VnodeOps 接口实现
+static struct VnodeOps g_procfsVops = { 
     .Lookup = VfsProcfsLookup,
     .Getattr = VfsProcfsStat,
     .Readdir = VfsProcfsReaddir,
@@ -351,13 +351,13 @@ static struct VnodeOps g_procfsVops = {
     .Closedir = VfsProcfsClosedir,
     .Truncate = VfsProcfsTruncate
 };
-
+// proc 对 file_operations_vfs 接口实现
 static struct file_operations_vfs g_procfsFops = {
-    .read = VfsProcfsRead,
-    .write = VfsProcfsWrite,
-    .open = VfsProcfsOpen,
-    .close = VfsProcfsClose
+    .read = VfsProcfsRead,	// 最终调用 ProcFileOperations -> read
+    .write = VfsProcfsWrite,// 最终调用 ProcFileOperations -> write
+    .open = VfsProcfsOpen,	// 最终调用 ProcFileOperations -> open
+    .close = VfsProcfsClose	// 最终调用 ProcFileOperations -> release
 };
-
+//文件系统注册入口
 FSMAP_ENTRY(procfs_fsmap, "procfs", procfs_operations, FALSE, FALSE);
 #endif

fs/proc/os_adapt/uptime_proc.c

@@ -37,7 +37,7 @@
 #define MSEC_TO_NSEC        1000000
 #define SEC_TO_MSEC         1000
 #define DECIMAL_TO_PERCENT  100
-
+//cat /proc/uptime 的实现函数
 static int UptimeProcFill(struct SeqBuf *seqBuf, void *v)
 {
     struct timespec curtime = {0, 0};
@@ -69,9 +69,9 @@ static int UptimeProcFill(struct SeqBuf *seqBuf, void *v)
 #endif
     return 0;
 }
-
+//替换了 read 接口的实现
 static const struct ProcFileOperations UPTIME_PROC_FOPS = {
-    .read       = UptimeProcFill,
+    .read       = UptimeProcFill,//读取接口的实现
 };
 
 void ProcUptimeInit(void)

fs/proc/src/proc_file.c

@@ -92,7 +92,7 @@ static struct ProcDirEntry *ProcFindNode(struct ProcDirEntry *parent, const char
  * return: the file of handle
  * add by ll
  */
-struct ProcDirEntry *ProcFindEntry(const char *path)
+struct ProcDirEntry *ProcFindEntry(const char *path)//查看内容项
 {
     struct ProcDirEntry *pn = NULL;
     int isfoundsub;
@@ -162,7 +162,7 @@ struct ProcDirEntry *ProcFindEntry(const char *path)
     spin_unlock(&procfsLock);
     return NULL;
 }
-
+//检查 proc名称有效性
 static int CheckProcName(const char *name, struct ProcDirEntry **parent, const char **lastName)
 {
     struct ProcDirEntry *pn = *parent;
@@ -198,7 +198,7 @@ static int CheckProcName(const char *name, struct ProcDirEntry **parent, const c
 
     return 0;
 }
-
+//分配 proc 节点
 static struct ProcDirEntry *ProcAllocNode(struct ProcDirEntry **parent, const char *name, mode_t mode)
 {
     struct ProcDirEntry *pn = NULL;
@@ -220,8 +220,8 @@ static struct ProcDirEntry *ProcAllocNode(struct ProcDirEntry **parent, const ch
     if ((S_ISDIR((*parent)->mode) == 0) || (strchr(lastName, '/'))) {
         return pn;
     }
-
-    pn = (struct ProcDirEntry *)malloc(sizeof(struct ProcDirEntry));
+	//开始各种造初始数据
+    pn = (struct ProcDirEntry *)malloc(sizeof(struct ProcDirEntry));//从内核分配内存
     if (pn == NULL) {
         return NULL;
     }
@@ -230,7 +230,7 @@ static struct ProcDirEntry *ProcAllocNode(struct ProcDirEntry **parent, const ch
         mode |= S_IRUSR | S_IRGRP | S_IROTH;
     }
 
-    (void)memset_s(pn, sizeof(struct ProcDirEntry), 0, sizeof(struct ProcDirEntry));
+    (void)memset_s(pn, sizeof(struct ProcDirEntry), 0, sizeof(struct ProcDirEntry));//初始化内存
     pn->nameLen = strlen(lastName);
     pn->mode = mode;
     ret = memcpy_s(pn->name, sizeof(pn->name), lastName, strlen(lastName) + 1);
@@ -253,7 +253,7 @@ static struct ProcDirEntry *ProcAllocNode(struct ProcDirEntry **parent, const ch
         return NULL;
     }
 
-    atomic_set(&pn->count, 1);
+    atomic_set(&pn->count, 1);//默认有一个引用
     spin_lock_init(&pn->pdeUnloadLock);
     return pn;
 }
@@ -315,14 +315,14 @@ static void ProcDetachNode(struct ProcDirEntry *pn)
     }
     pn->parent = NULL;
 }
-
+//在参数 parent 下创建目录
 static struct ProcDirEntry *ProcCreateDir(struct ProcDirEntry *parent, const char *name,
                                           const struct ProcFileOperations *procFileOps, mode_t mode)
 {
     struct ProcDirEntry *pn = NULL;
     int ret;
 
-    pn = ProcAllocNode(&parent, name, S_IFDIR | mode);
+    pn = ProcAllocNode(&parent, name, S_IFDIR | mode);//分配一个节点
     if (pn == NULL) {
         return pn;
     }
@@ -337,20 +337,20 @@ static struct ProcDirEntry *ProcCreateDir(struct ProcDirEntry *parent, const cha
 
     return pn;
 }
-
+//创建文件项
 static struct ProcDirEntry *ProcCreateFile(struct ProcDirEntry *parent, const char *name,
                                            const struct ProcFileOperations *procFileOps, mode_t mode)
 {
     struct ProcDirEntry *pn = NULL;
     int ret;
 
-    pn = ProcAllocNode(&parent, name, S_IFREG | mode);
+    pn = ProcAllocNode(&parent, name, S_IFREG | mode);//分配一个节点,S_IFREG代表是文件类型
     if (pn == NULL) {
         return pn;
     }
 
-    pn->procFileOps = procFileOps;
-    pn->type = VNODE_TYPE_REG;
+    pn->procFileOps = procFileOps;//驱动程序
+    pn->type = VNODE_TYPE_REG;	//文件类型
     ret = ProcAddNode(parent, pn);
     if (ret != 0) {
         free(pn->pf);
@@ -366,9 +366,9 @@ struct ProcDirEntry *CreateProcEntry(const char *name, mode_t mode, struct ProcD
     struct ProcDirEntry *pde = NULL;
 
     if (S_ISDIR(mode)) {//目录模式 0
-        pde = ProcCreateDir(parent, name, NULL, mode);
+        pde = ProcCreateDir(parent, name, NULL, mode);//无驱动程序
     } else {
-        pde = ProcCreateFile(parent, name, NULL, mode);
+        pde = ProcCreateFile(parent, name, NULL, mode);//无驱动程序
     }
     return pde;
 }
@@ -440,7 +440,7 @@ struct ProcDirEntry *ProcMkdir(const char *name, struct ProcDirEntry *parent)
 {
     return ProcCreateDir(parent, name, NULL, 0);
 }
-
+//创建数据
 struct ProcDirEntry *ProcCreateData(const char *name, mode_t mode, struct ProcDirEntry *parent,
                                     const struct ProcFileOperations *procFileOps, void *data)
 {
@@ -499,7 +499,7 @@ static int GetNextDir(struct ProcDirEntry *pn, void *buf, size_t len)
     pn->pf->fPos++;
     return ENOERR;
 }
-
+//打开 pro 
 int ProcOpen(struct ProcFile *procFile)
 {
     if (procFile == NULL) {
@@ -509,7 +509,7 @@ int ProcOpen(struct ProcFile *procFile)
         return OK;
     }
 
-    struct SeqBuf *buf = LosBufCreat();
+    struct SeqBuf *buf = LosBufCreat();//创建一个 seq buf
     if (buf == NULL) {
         return PROC_ERROR;
     }
@@ -597,7 +597,7 @@ int ReadProcFile(struct ProcDirEntry *pde, void *buf, size_t len)
     }
     return result;
 }
-
+//写 proc 文件
 int WriteProcFile(struct ProcDirEntry *pde, const void *buf, size_t len)
 {
     int result = -EPERM;
@@ -618,7 +618,7 @@ int WriteProcFile(struct ProcDirEntry *pde, const void *buf, size_t len)
 
     return result;
 }
-
+// seek proc 文件
 loff_t LseekProcFile(struct ProcDirEntry *pde, loff_t offset, int whence)
 {
     if (pde == NULL || pde->pf == NULL) {

fs/proc/src/proc_shellcmd.c

@@ -87,17 +87,17 @@ int OsShellCmdWriteProc(int argc, char **argv)
     char realPath[PATH_MAX] = {'\0'};
     const char *rootProcDir = "/proc/";
 
-    if (argc == WRITEPROC_ARGC) {
-        value = argv[0];
-        path = argv[2];
+    if (argc == WRITEPROC_ARGC) {//argv[0] = ">>"
+        value = argv[0];//test
+        path = argv[2];///proc/uptime
         len = strlen(value) + 1;  /* +1:add the \0 */
-        if (strncmp(argv[1], ">>", strlen(">>")) == 0) {
+        if (strncmp(argv[1], ">>", strlen(">>")) == 0) { //  第二个参数必须得是 >>
             if ((realpath(path, realPath) == NULL) || (strncmp(realPath, rootProcDir, strlen(rootProcDir)) != 0)) {
                 PRINT_ERR("No such file or directory\n");
                 return PROC_ERROR;
             }
 
-            handle = OpenProcFile(realPath, O_TRUNC);
+            handle = OpenProcFile(realPath, O_TRUNC);//打开 proc 文件
             if (handle == NULL) {
                 PRINT_ERR("No such file or directory\n");
                 return PROC_ERROR;

fs/vfs/operation/fs_other.c

@@ -623,7 +623,7 @@ void ls(const char *pathname)
     return;
 }
 
-
+//
 char *realpath(const char *path, char *resolved_path)
 {
     int ret, result;
@@ -637,7 +637,7 @@ char *realpath(const char *path, char *resolved_path)
         return NULL;
     }
 
-    result = stat(new_path, &buf);
+    result = stat(new_path, &buf);//获取统计信息,即属性信息
 
     if (resolved_path == NULL) {
         if (result != ENOERR) {

fs/vfs/operation/fullpath.c

@@ -241,7 +241,7 @@ static char *vfs_normalize_fullpath(const char *directory, const char *filename,
 
     return fullpath;
 }
-//通过目录和文件名找(绝对)路径
+//虚拟文件系统 | 标准化路径
 int vfs_normalize_path(const char *directory, const char *filename, char **pathname)
 {
     char *fullpath = NULL;

fs/vfs/vfs_cmd/vfs_shellcmd.c

@@ -223,7 +223,7 @@ cat用于显示文本文件的内容。
 使用实例
 举例：cat harmony.txt
 *******************************************************/
-int osShellCmdDoCatShow(UINTPTR arg)
+int osShellCmdDoCatShow(UINTPTR arg) //shellcmd_cat 任务实现
 {
   int ret = 0;
   char buf[CAT_BUF_SIZE];
@@ -233,7 +233,7 @@ int osShellCmdDoCatShow(UINTPTR arg)
   FILE *ini = NULL;
 
   (void)pthread_mutex_lock(&g_mutex_cat);
-  ini = fopen(fullpath, "r");
+  ini = fopen(fullpath, "r");//打开文件
   if (ini == NULL)
     {
       ret = -1;
@@ -244,7 +244,7 @@ int osShellCmdDoCatShow(UINTPTR arg)
   do
     {
       (void)memset_s(buf, sizeof(buf), 0, CAT_BUF_SIZE);
-      size = fread(buf, 1, CAT_BUF_SIZE, ini);
+      size = fread(buf, 1, CAT_BUF_SIZE, ini); //读取文件内容
       if ((int)size < 0)
         {
           ret = -1;
@@ -291,7 +291,7 @@ int osShellCmdCat(int argc, const char **argv)
   unsigned int ca_task;
   struct Vnode *vnode = NULL;
   TSK_INIT_PARAM_S init_param;
-  char *shell_working_directory = OsShellGetWorkingDirtectory();
+  char *shell_working_directory = OsShellGetWorkingDirtectory();//显示当前目录 pwd
   if (shell_working_directory == NULL)
     {
       return -1;
@@ -299,7 +299,7 @@ int osShellCmdCat(int argc, const char **argv)
 
   ERROR_OUT_IF(argc != 1, PRINTK("cat [FILE]\n"), return -1);
 
-  ret = vfs_normalize_path(shell_working_directory, argv[0], &fullpath);
+  ret = vfs_normalize_path(shell_working_directory, argv[0], &fullpath);//由相对路径获取绝对路径
   ERROR_OUT_IF(ret < 0, set_err(-ret, "cat error"), return -1);
 
   VnodeHold();
@@ -323,14 +323,14 @@ int osShellCmdCat(int argc, const char **argv)
   VnodeDrop();
   (void)memset_s(&init_param, sizeof(init_param), 0, sizeof(TSK_INIT_PARAM_S));
   init_param.pfnTaskEntry = (TSK_ENTRY_FUNC)osShellCmdDoCatShow;
-  init_param.usTaskPrio   = CAT_TASK_PRIORITY;
-  init_param.auwArgs[0]   = (UINTPTR)fullpath;
-  init_param.uwStackSize  = CAT_TASK_STACK_SIZE;
-  init_param.pcName       = "shellcmd_cat";
+  init_param.usTaskPrio   = CAT_TASK_PRIORITY;	//优先级10
+  init_param.auwArgs[0]   = (UINTPTR)fullpath;	//入口参数
+  init_param.uwStackSize  = CAT_TASK_STACK_SIZE;//内核栈大小
+  init_param.pcName       = "shellcmd_cat";	//任务名称
   init_param.uwResved     = LOS_TASK_STATUS_DETACHED | OS_TASK_FLAG_SPECIFIES_PROCESS;
-  init_param.processID    = 2; /* 2: kProcess */
+  init_param.processID    = 2; /* 2: kProcess */ //内核任务
 
-  ret = (int)LOS_TaskCreate(&ca_task, &init_param);
+  ret = (int)LOS_TaskCreate(&ca_task, &init_param);//创建任务显示cat内容
 
   if (ret != LOS_OK)
     {

kernel/base/include/los_task_pri.h

@@ -200,13 +200,13 @@ extern SPIN_LOCK_S g_taskSpin;//任务自旋锁
  *
  * The task is system-level task, like idle, swtmr and etc.
  */
-#define OS_TASK_FLAG_SYSTEM_TASK    0x1000U
+#define OS_TASK_FLAG_SYSTEM_TASK    0x1000U	//系统任务
 
 /**
  * @ingroup los_task
  * Flag that indicates the task property.
  *
- * The task is no-delete system task, like resourceTask.
+ * The task is no-delete system task, like resourceTask. //该任务是不可删除的系统任务，如资源回收任务
  */
 #define OS_TASK_FLAG_NO_DELETE    0x2000U
 
@@ -216,7 +216,7 @@ extern SPIN_LOCK_S g_taskSpin;//任务自旋锁
  *
  * Kills the thread during process exit.
  */
-#define OS_TASK_FLAG_EXIT_KILL       0x4000U
+#define OS_TASK_FLAG_EXIT_KILL       0x4000U //在进程退出期间一同被干掉的任务
 
 /**
  * @ingroup los_task
@@ -224,14 +224,14 @@ extern SPIN_LOCK_S g_taskSpin;//任务自旋锁
  *
  * Specifies the process creation task.
  */
-#define OS_TASK_FLAG_SPECIFIES_PROCESS 0x0U
+#define OS_TASK_FLAG_SPECIFIES_PROCESS 0x0U //创建指定任务 例如: cat weharmony.net 实现 
 
 /**
  * @ingroup los_task
  * Boundary on which the stack size is aligned.
  *
  */
-#define OS_TASK_STACK_SIZE_ALIGN    16U
+#define OS_TASK_STACK_SIZE_ALIGN    16U //堆栈大小对齐的边界
 
 /**
  * @ingroup los_task
@@ -243,7 +243,7 @@ extern SPIN_LOCK_S g_taskSpin;//任务自旋锁
 /**
  * @ingroup los_task
  * Number of usable task priorities.
- */
+ */	//可用任务优先级的数量
 #define OS_TSK_PRINUM               (OS_TASK_PRIORITY_LOWEST - OS_TASK_PRIORITY_HIGHEST + 1)
 
 /**

kernel/include/los_tables.h

@@ -39,6 +39,9 @@
 extern "C" {
 #endif /* __cplusplus */
 #endif /* __cplusplus */
+/*
+HAL层主要功能是实现轻OpenHarmony与芯片的解耦，
+*/
 
 #ifndef LOS_HAL_TABLE_BEGIN
 #define LOS_HAL_TABLE_BEGIN(label, name)                                     \

kernel/include/los_task.h

@@ -59,7 +59,7 @@ extern "C" {
  *
  * The task is automatically deleted.
  */
-#define LOS_TASK_STATUS_DETACHED                0x0800U
+#define LOS_TASK_STATUS_DETACHED                0x0800U //任务被自动删除
 
 /**
  * @ingroup los_task