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

@@ -78,7 +78,7 @@ typedef unsigned short fmode_t;
 #define FMODE_READ        ((fmode_t)0x1)
 
 struct ProcFile;
-
+//操作pro file的抽象接口,proc本质是个内存文件系统, 
 struct ProcFileOperations {
     char *name;
     ssize_t (*write)(struct ProcFile *pf, const char *buf, size_t count, loff_t *ppos);
@@ -86,32 +86,32 @@ struct ProcFileOperations {
     int (*release)(struct Vnode *vnode, struct ProcFile *pf);
     int (*read)(struct SeqBuf *m, void *v);
 };
-
+//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;
-    struct ProcDirEntry *next, *parent, *subdir;
+    struct ProcDirEntry *next, *parent, *subdir;//当前目录项的关系项
     void *data;
     atomic_t count; /* open file count */
     spinlock_t pdeUnloadLock;
 
     int nameLen;
-    struct ProcDirEntry *pdirCurrent;
+    struct ProcDirEntry *pdirCurrent;//当前目录
     char name[NAME_MAX];
-    enum VnodeType type;
+    enum VnodeType type;	//节点类型
 };
-
+//Proc文件结构体,对标 FILE 结构体
 struct ProcFile {
-    fmode_t fMode;
-    spinlock_t fLock;
-    atomic_t fCount;
-    struct SeqBuf *sbuf;
-    struct ProcDirEntry *pPDE;
-    unsigned long long fVersion;
-    loff_t fPos;
-    char name[NAME_MAX];
+    fmode_t fMode;		//操作文件的模式
+    spinlock_t fLock;	//自旋锁
+    atomic_t fCount;	//原子操作
+    struct SeqBuf *sbuf;//序列号BUF
+    struct ProcDirEntry *pPDE;//目录项
+    unsigned long long fVersion;//版本号
+    loff_t fPos;	//文件操作偏移位
+    char name[NAME_MAX];//文件名
 };
 
 struct ProcStat {

fs/proc/os_adapt/mounts_proc.c

@@ -37,15 +37,15 @@
 
 #include "fs/file.h"
 #include "internal.h"
-
+//显示文件系统类型,将被作为回调函数回调
 static int ShowType(const char *mountPoint, struct statfs *statBuf, void *arg)
 {
     struct SeqBuf *seqBuf = (struct SeqBuf *)arg;
     char *type = NULL;
     char *name = NULL;
 
-    switch (statBuf->f_type) {
-        case PROCFS_MAGIC:
+    switch (statBuf->f_type) {//目前鸿蒙支持的文件系统
+        case PROCFS_MAGIC:	
             type = "proc";
             name = "proc";
             break;
@@ -72,12 +72,12 @@ static int ShowType(const char *mountPoint, struct statfs *statBuf, void *arg)
         default:
             return 0;
     }
-
-    (void)LosBufPrintf(seqBuf, "%s %s %s\n", name, mountPoint, type);
+	
+    (void)LosBufPrintf(seqBuf, "%s %s %s\n", name, mountPoint, type);//打印到 seqBuf 中,即 arg中
 
     return 0;
 }
-
+// 读取 mount 接口实现
 static int MountsProcFill(struct SeqBuf *m, void *v)
 {
     foreach_mountpoint_t handler = ShowType;
@@ -85,7 +85,7 @@ static int MountsProcFill(struct SeqBuf *m, void *v)
 
     return 0;
 }
-
+//实现 操作proc file 接口,也可理解为驱动程序不同
 static const struct ProcFileOperations MOUNTS_PROC_FOPS = {
     .read = MountsProcFill,
 };

fs/proc/os_adapt/proc_init.c

@@ -36,31 +36,31 @@
 #include "sys/stat.h"
 #include "los_init.h"
 
-#ifdef LOSCFG_FS_PROC
-
+#ifdef LOSCFG_FS_PROC //使能 PROC 模块
+//pro file 初始化
 void ProcFsInit(void)
 {
     int ret;
 
-    ret = mkdir(PROCFS_MOUNT_POINT, 0);
+    ret = mkdir(PROCFS_MOUNT_POINT, 0);//创建 "/proc"
     if (ret < 0) {
         PRINT_ERR("failed to mkdir %s, errno = %d\n", PROCFS_MOUNT_POINT, get_errno());
         return;
     }
-
+	//装载文件系统
     ret = mount(NULL, PROCFS_MOUNT_POINT, "procfs", 0, NULL);
     if (ret) {
         PRINT_ERR("mount procfs err %d\n", ret);
         return;
     }
 
-    ProcMountsInit();
+    ProcMountsInit();//初始化 /pro/mounts
 #if defined(LOSCFG_SHELL_CMD_DEBUG) && defined(LOSCFG_KERNEL_VM)
-    ProcVmmInit();
+    ProcVmmInit();//初始化 /pro/vmm
 #endif
-    ProcProcessInit();
-    ProcUptimeInit();
-    ProcKernelTraceInit();
+    ProcProcessInit();//初始化 /pro/process
+    ProcUptimeInit();//初始化 /pro/uptime
+    ProcKernelTraceInit();//初始化 /pro/ktrace
 }
 
 LOS_MODULE_INIT(ProcFsInit, LOS_INIT_LEVEL_KMOD_EXTENDED);

fs/proc/os_adapt/process_proc.c

@@ -33,18 +33,18 @@
 #include <sys/mount.h>
 #include "proc_fs.h"
 #include "los_process_pri.h"
-
+//这个太牛了,直接读 taskinfo,注意 SeqBuf 的第一个参数是 char* buf
 static int ProcessProcFill(struct SeqBuf *m, void *v)
 {
     (void)v;
     (void)OsShellCmdTskInfoGet(OS_ALL_TASK_MASK, m, OS_PROCESS_INFO_ALL);
     return 0;
 }
-
+// 对 /proc/process 各种骚操作,只能读
 static const struct ProcFileOperations PROCESS_PROC_FOPS = {
-    .read       = ProcessProcFill,
+    .read       = ProcessProcFill,//读取操作
 };
-
+//创建进程相关信息 /proc/process
 void ProcProcessInit(void)
 {
     struct ProcDirEntry *pde = CreateProcEntry("process", 0, NULL);

fs/proc/os_adapt/vmm_proc.c

@@ -40,7 +40,7 @@
 #include "los_process_pri.h"
 
 #ifdef LOSCFG_KERNEL_VM
-
+//获取虚拟内存内核相关的信息,用这个方法去窥视内核是个很好的办法,精读本函数的过程是理解虚拟内存实现的过程
 STATIC VOID OsVmDumpSeqSpaces(struct SeqBuf *seqBuf)
 {
     LosVmSpace *space = NULL;
@@ -89,7 +89,7 @@ STATIC VOID OsVmDumpSeqSpaces(struct SeqBuf *seqBuf)
     }
     (VOID)LOS_MuxRelease(aspaceListMux);
 }
-
+// .read 接口的现实
 static int VmmProcFill(struct SeqBuf *m, void *v)
 {
     (void)v;
@@ -97,21 +97,21 @@ static int VmmProcFill(struct SeqBuf *m, void *v)
 
     return 0;
 }
-
+//实现 操作proc file 接口,也可理解为驱动程序不同
 static const struct ProcFileOperations VMM_PROC_FOPS = {
     .write      = NULL,
     .read       = VmmProcFill,
 };
-
+//初始化 虚拟内存 内容信息 
 void ProcVmmInit(void)
 {
-    struct ProcDirEntry *pde = CreateProcEntry("vmm", 0, NULL);
+    struct ProcDirEntry *pde = CreateProcEntry("vmm", 0, NULL);//创建目录
     if (pde == NULL) {
         PRINT_ERR("create /proc/vmm error!\n");
         return;
     }
 
-    pde->procFileOps = &VMM_PROC_FOPS;
+    pde->procFileOps = &VMM_PROC_FOPS;//每个目录的驱动程序都不一样
 }
 #endif
 #endif

fs/proc/src/proc_file.c

@@ -39,25 +39,25 @@
 #define MIN(a, b) ((a) < (b) ? (a) : (b))
 #define PROC_ROOTDIR_NAMELEN   5
 #define PROC_INUSE             2
-
-DEFINE_SPINLOCK(procfsLock);
-bool procfsInit = false;
+//定义自旋锁,说明 procfs不支持多线程访问
+DEFINE_SPINLOCK(procfsLock);//定义profs 自旋锁
+bool procfsInit = false;	//是否初始化了profs
 
 static struct ProcFile g_procPf = {
     .fPos       = 0,
 };
 
-static struct ProcDirEntry g_procRootDirEntry = {
+static struct ProcDirEntry g_procRootDirEntry = { //proc 根部 即 /proc
     .nameLen     = 5,
-    .mode        = S_IFDIR | S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH,
+    .mode        = S_IFDIR | S_IRUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH,//(04555)
     .count       = ATOMIC_INIT(1),
-    .procFileOps = NULL,
-    .parent      = &g_procRootDirEntry,
-    .name        = "/proc",
-    .subdir      = NULL,
-    .next        = NULL,
-    .pf          = &g_procPf,
-    .type        = VNODE_TYPE_DIR,
+    .procFileOps = NULL,//对根节点无操作需求
+    .parent      = &g_procRootDirEntry,//自己当爹又当儿
+    .name        = "/proc", 
+    .subdir      = NULL,	//暂无,后续必有子
+    .next        = NULL,	//暂无.后续必有续
+    .pf          = &g_procPf,		//全局PRO文件	
+    .type        = VNODE_TYPE_DIR,	//是个目录
 };
 
 int ProcMatch(unsigned int len, const char *name, struct ProcDirEntry *pn)
@@ -360,12 +360,12 @@ static struct ProcDirEntry *ProcCreateFile(struct ProcDirEntry *parent, const ch
 
     return pn;
 }
-
+//创建 pro (目录/文件)项
 struct ProcDirEntry *CreateProcEntry(const char *name, mode_t mode, struct ProcDirEntry *parent)
 {
     struct ProcDirEntry *pde = NULL;
 
-    if (S_ISDIR(mode)) {
+    if (S_ISDIR(mode)) {//目录模式 0
         pde = ProcCreateDir(parent, name, NULL, mode);
     } else {
         pde = ProcCreateFile(parent, name, NULL, mode);

fs/proc/src/proc_shellcmd.c

@@ -49,7 +49,33 @@
 #include "proc_fs.h"
 
 #define WRITEPROC_ARGC  3
+/*****************************************************************
+鸿蒙内核提供了一种通过 /proc 文件系统，在运行时访问内核内部数据结构、改变内核设置的机制。
+proc文件系统是一个伪文件系统，它只存在内存当中，而不占用外存空间。它以文件系统的方式为
+访问系统内核数据的操作提供接口。
+用户和应用程序可以通过proc得到系统的信息，并可以改变内核的某些参数。由于系统的信息，
+如进程，是动态改变的，所以用户或应用程序读取proc文件时，proc文件系统是动态从系统内核读出
+所需信息并提交的。
 
+proc fs支持传入字符串参数，需要每个文件实现自己的写方法。
+命令格式
+writeproc <data> >> /proc/<filename>
+
+参数说明
+参数			参数说明		
+data		要输入的字符串，以空格为结束符，如需输入空格，请用""包裹。
+filename	data要传入的proc文件。
+
+proc文件实现自身的write函数，调用writeproc命令后会将入参传入write函数。
+	注意:procfs暂不支持多线程访问
+	
+OHOS # writeproc test >> /proc/uptime
+
+[INFO]write buf is: test
+test >> /proc/uptime
+ 说明： uptime proc文件临时实现write函数，INFO日志为实现的测试函数打印的日志。
+
+*****************************************************************/
 int OsShellCmdWriteProc(int argc, char **argv)
 {
     int i;

kernel/base/misc/task_shellcmd.c

@@ -95,7 +95,7 @@ STATIC UINT32 *taskWaterLine = NULL;
 #else
 #define PROCESS_INFO_SHOW(seqBuf, arg...) PRINTK(arg)
 #endif
-
+
 LITE_OS_SEC_TEXT_MINOR UINT8 *OsShellCmdProcessMode(UINT16 mode)
 {
     if (mode == OS_KERNEL_MODE) {
@@ -109,9 +109,9 @@ LITE_OS_SEC_TEXT_MINOR UINT8 *OsShellCmdProcessMode(UINT16 mode)
 
 LITE_OS_SEC_TEXT_MINOR UINT8 *OsShellCmdSchedPolicy(UINT16 policy)
 {
-    if (policy == LOS_SCHED_RR) {
+    if (policy == LOS_SCHED_RR) {
         return (UINT8 *)"RR";
-    } else if (policy == LOS_SCHED_FIFO) {
+    } else if (policy == LOS_SCHED_FIFO) {
         return (UINT8 *)"FIFO";
     } else if (policy == LOS_SCHED_IDLE) {
         return (UINT8 *)"IDLE";
@@ -119,25 +119,25 @@ LITE_OS_SEC_TEXT_MINOR UINT8 *OsShellCmdSchedPolicy(UINT16 policy)
 
     return (UINT8 *)"ERROR";
 }
-
+
 LITE_OS_SEC_TEXT_MINOR UINT8 *OsShellProcessStatus(UINT16 status)
 {
     status = status & OS_PROCESS_STATUS_MASK;
-    if (status & OS_PROCESS_STATUS_ZOMBIES) {
+    if (status & OS_PROCESS_STATUS_ZOMBIES) {
         return (UINT8 *)"Zombies";
-    } else if (status & OS_PROCESS_STATUS_INIT) {
+    } else if (status & OS_PROCESS_STATUS_INIT) {
         return (UINT8 *)"Init";
-    } else if (status & OS_PROCESS_STATUS_RUNNING) {
+    } else if (status & OS_PROCESS_STATUS_RUNNING) {
         return (UINT8 *)"Running";
-    } else if (status & OS_PROCESS_STATUS_READY) {
+    } else if (status & OS_PROCESS_STATUS_READY) {
         return (UINT8 *)"Ready";
-    } else if (status & OS_PROCESS_STATUS_PENDING) {
+    } else if (status & OS_PROCESS_STATUS_PENDING) {
         return (UINT8 *)"Pending";
     }
 
     return (UINT8 *)"Invalid";
 }
-
+
 STATIC VOID OsShellCmdProcessTitle(VOID *seqBuf, UINT16 flag)
 {
     PROCESS_INFO_SHOW(seqBuf, "\r\n  PID  PPID PGID       UID  Status ");
@@ -204,14 +204,14 @@ STATIC VOID OsShellCmdAllProcessInfoShow(const LosProcessCB *pcbArray, const INT
 
     for (pid = 1; pid < g_processMaxNum; ++pid) {
         processCB = pcbArray + pid;
-        if (OsProcessIsUnused(processCB)) {
+        if (OsProcessIsUnused(processCB)) {
             continue;
         }
 
         OsShellCmdProcessInfoShow(processCB, group, memArray, seqBuf, flag);
     }
 }
-
+
 #ifdef LOSCFG_KERNEL_VM
 STATIC VOID OsProcessMemUsageGet(UINT32 *memArray)
 {
@@ -221,7 +221,7 @@ STATIC VOID OsProcessMemUsageGet(UINT32 *memArray)
 
     for (pid = 0; pid < g_processMaxNum; ++pid) {
         processCB = g_processCBArray + pid;
-        if (OsProcessIsUnused(processCB)) {
+        if (OsProcessIsUnused(processCB)) {
             continue;
         }
         proMemUsage = &memArray[pid * PROCESS_VM_INDEX_MAX];
@@ -504,7 +504,7 @@ STATIC VOID OsShellCmdAllTaskInfoData(const LosTaskCB *allTaskArray, VOID *seqBu
         }
     }
 }
-
+
 STATIC VOID OsShellCmdTskInfoData(const LosTaskCB *allTaskArray, VOID *seqBuf, UINT16 flag)
 {
     OsShellCmdTskInfoTitle(seqBuf, flag);
@@ -532,7 +532,7 @@ STATIC VOID OsProcessAndTaskInfoGet(LosProcessCB **pcbArray, INT32 **group, LosT
         SCHEDULER_UNLOCK(intSave);
     }
 }
-
+//获取任务相关信息
 LITE_OS_SEC_TEXT_MINOR UINT32 OsShellCmdTskInfoGet(UINT32 taskID, VOID *seqBuf, UINT16 flag)
 {
     UINT32 size;
@@ -554,15 +554,15 @@ LITE_OS_SEC_TEXT_MINOR UINT32 OsShellCmdTskInfoGet(UINT32 taskID, VOID *seqBuf,
         }
         (VOID)memset_s(pcbArray, size, 0, size);
         OsProcessAndTaskInfoGet(&pcbArray, &group, &tcbArray, &memArray, flag);
-        OsShellCmdProcessInfoData(pcbArray, group, memArray, seqBuf, flag);
-        OsShellCmdTskInfoData(tcbArray, seqBuf, flag);
+        OsShellCmdProcessInfoData(pcbArray, group, memArray, seqBuf, flag);
+        OsShellCmdTskInfoData(tcbArray, seqBuf, flag);
 
         (VOID)LOS_MemFree(m_aucSysMem1, pcbArray);
     }
 
     return LOS_OK;
 }
-
+
 LITE_OS_SEC_TEXT_MINOR UINT32 OsShellCmdDumpTask(INT32 argc, const CHAR **argv)
 {
     UINT32 flag = 0;
@@ -601,6 +601,6 @@ TASK_HELP:
 }
 
 #ifdef LOSCFG_SHELL
-SHELLCMD_ENTRY(task_shellcmd, CMD_TYPE_EX, "task", 1, (CmdCallBackFunc)OsShellCmdDumpTask);
+SHELLCMD_ENTRY(task_shellcmd, CMD_TYPE_EX, "task", 1, (CmdCallBackFunc)OsShellCmdDumpTask);
 #endif
 

kernel/common/los_seq_buf.c

@@ -31,8 +31,10 @@
 
 #include "los_seq_buf.h"
 #include <stdlib.h>
-
-static int ExpandSeqBuf(struct SeqBuf *seqBuf, size_t oldCount)
+/*
+	Sequential buffer 顺序缓存区 实现
+*/
+static int ExpandSeqBuf(struct SeqBuf *seqBuf, size_t oldCount)//扩展buf
 {
     char *newBuf = NULL;
     int ret;
@@ -45,21 +47,21 @@ static int ExpandSeqBuf(struct SeqBuf *seqBuf, size_t oldCount)
         goto EXPAND_FAILED;
     }
 
-    newBuf = (char*)malloc(seqBuf->size <<= 1);
+    newBuf = (char*)malloc(seqBuf->size <<= 1);//将现有buf扩大一倍
     if (newBuf == NULL) {
         goto EXPAND_FAILED;
     }
     (void)memset_s(newBuf + oldCount, seqBuf->size - oldCount, 0, seqBuf->size - oldCount);
-
-    ret = memcpy_s(newBuf, seqBuf->size, seqBuf->buf, oldCount);
+	//memset_s 注意 oldCount 位置,因为 newBuf头部要被旧buf覆盖,所以只set后部分
+    ret = memcpy_s(newBuf, seqBuf->size, seqBuf->buf, oldCount);//拷贝旧buf数据到新buf,注意 oldCount 位置
     if (ret != LOS_OK) {
         free(newBuf);
         goto EXPAND_FAILED;
     }
-    seqBuf->count = oldCount;
+    seqBuf->count = oldCount;//目前偏移量,可理解为seek 
 
-    free(seqBuf->buf);
-    seqBuf->buf = newBuf;
+    free(seqBuf->buf);//释放原有的buf
+    seqBuf->buf = newBuf;//采用新的buf
 
     return LOS_OK;
 EXPAND_FAILED:
@@ -70,7 +72,7 @@ EXPAND_FAILED:
 
     return -LOS_NOK;
 }
-
+//创建seq buf
 struct SeqBuf *LosBufCreat(void)
 {
     struct SeqBuf *seqBuf = NULL;
@@ -84,7 +86,7 @@ struct SeqBuf *LosBufCreat(void)
 
     return seqBuf;
 }
-
+//真正写 buf 函数,调整 size/count的值,count可理解为偏移位
 int LosBufVprintf(struct SeqBuf *seqBuf, const char *fmt, va_list argList)
 {
     bool needreprintf = FALSE;
@@ -109,10 +111,10 @@ int LosBufVprintf(struct SeqBuf *seqBuf, const char *fmt, va_list argList)
                              seqBuf->size - seqBuf->count - 1, fmt, argList);
         if (bufLen >= 0) {
             /* succeed write. */
-            seqBuf->count += bufLen;
+            seqBuf->count += bufLen;//成功写入,count要增长
             return 0;
         }
-        if (seqBuf->buf[seqBuf->count] == '\0') {
+        if (seqBuf->buf[seqBuf->count] == '\0') {//这里没看懂,为啥要有这个判断, @note_thinking
             free(seqBuf->buf);
             seqBuf->buf = NULL;
             break;
@@ -127,19 +129,19 @@ int LosBufVprintf(struct SeqBuf *seqBuf, const char *fmt, va_list argList)
 
     return -LOS_NOK;
 }
-
+//支持可变参数 写 buf
 int LosBufPrintf(struct SeqBuf *seqBuf, const char *fmt, ...)
 {
     va_list argList;
     int ret;
 
-    va_start(argList, fmt);
+    va_start(argList, fmt);//可变参数的实现,有点意思.
     ret = LosBufVprintf(seqBuf, fmt, argList);
     va_end(argList);
 
     return ret;
 }
-
+//释放 seq buf
 int LosBufRelease(struct SeqBuf *seqBuf)
 {
     if (seqBuf == NULL) {

kernel/common/los_seq_buf.h

@@ -41,13 +41,13 @@ extern "C" {
 #endif /* __cplusplus */
 #endif /* __cplusplus */
 
-#define SEQBUF_PAGE_SIZE  4096
-#define SEQBUF_LIMIT_SIZE (256 * SEQBUF_PAGE_SIZE)
-
+#define SEQBUF_PAGE_SIZE  4096	//4K 一页
+#define SEQBUF_LIMIT_SIZE (256 * SEQBUF_PAGE_SIZE) //缓冲区最大空间为1M
+//序列化BUF
 struct SeqBuf {
-    char *buf;
-    size_t size;
-    size_t count;
+    char *buf;	//内容
+    size_t size;//buf大小
+    size_t count;//当前位置
     void *private;
 };
 

zzz/git/push.sh

 git add -A
-git commit -m  '理解 进程文件描述符 和 系统文件描述 是理解FD的关键.
+git commit -m  '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.gitee.io
+    国内:https://weharmony.21cloudbox.com
     国外:https://weharmony.github.io
 '