【主线待合】增加tail命令，解决lfs初始化问题，修复Rd_Mgets

library/common/rd_stdio.c

@@ -56,12 +56,14 @@ lfs_t g_lfs;
 lfs_flashbd_t g_bd;
 struct lfs_flashbd_config g_bd_cfg;
 struct lfs_config g_cfg;
+static uint8_t g_lfs_ready = 0;   /* mount 成功后才允许读写，防止 mount 失败后继续写坏盘 */
 #endif
 
 #ifndef WIN32
 WEAK void *Rd_Fopen(const char *path, const char *mode)
 {
 #ifdef USE_W25QXX
+	if (!g_lfs_ready) return NULL;
 #if LV_USE_FS_LITTLEFS
 	lv_fs_mode_t lv_mode;
 	if (strchr(mode, 'r') != NULL) lv_mode = LV_FS_MODE_RD;
@@ -144,6 +146,7 @@ WEAK ssize_t Rd_Mread(void *buf, size_t count, void *file)
 WEAK ssize_t Rd_Mwrite(const void *buf, size_t count, void *file)
 {
 #ifdef USE_W25QXX
+	if (!g_lfs_ready) return RD_FAILURE;
 #if LV_USE_FS_LITTLEFS
 	uint32_t size = 0;
 	lv_fs_file_t *fp = (lv_fs_file_t *)file;
@@ -244,7 +247,7 @@ WEAK char *Rd_Mgets(char *buf, int size, void *file)
 	while (i < size - 1)
 	{
 		ssize_t n = Rd_Mread(&c, 1, file);
-		if (n != 0)
+		if (n != 1)
 		{
 			// 读到 EOF 或 错误（Rd_Mread 返回 0 表示读满请求的字节数）
 			if (i == 0) return NULL; // 什么都没读到
@@ -334,6 +337,7 @@ WEAK int Rd_fflush(void *file)
 WEAK int Rd_remove(const char *filename)
 {
 #ifdef USE_W25QXX
+	if (!g_lfs_ready) return RD_FAILURE;
 	const char *p = filename;
 	if (strlen(filename) >= 2 && filename[1] == ':') p = filename + 2;
 	int err = lfs_remove(&g_lfs, p);
@@ -347,6 +351,7 @@ WEAK int Rd_remove(const char *filename)
 WEAK int Rd_rename(const char *oldpath, const char *newpath)
 {
 #ifdef USE_W25QXX
+	if (!g_lfs_ready) return RD_FAILURE;
 	const char *o = oldpath, *n = newpath;
 	if (strlen(oldpath) >= 2 && oldpath[1] == ':') o = oldpath + 2;
 	if (strlen(newpath) >= 2 && newpath[1] == ':') n = newpath + 2;
@@ -375,12 +380,32 @@ WEAK void Rd_LittleFSInit(void)
 	lfs_flashbd_default_config(&g_cfg, &g_bd, &g_bd_cfg, 1 * 1024 * 1024, 12 * 256, NULL, NULL, NULL);
 
 	int err = lfs_mount(&g_lfs, &g_cfg);
-	if (err)
+	if (err == LFS_ERR_CORRUPT)
 	{
-		printf("mount error format...\n");
-		(void)Rd_Lfs_Mount();
+		/* 只有真正的“无文件系统/损坏”才格式化；IO/内存错误格式化只会越弄越糟 */
+		printf("lfs: no fs / corrupt, formatting...\n");
+		err = lfs_format(&g_lfs, &g_cfg);
+		if (err == LFS_ERR_OK)
+		{
+			err = lfs_mount(&g_lfs, &g_cfg);
+		}
+		else
+		{
+			printf("lfs: format failed, err=%d\n", err);
+		}
 	}
+	else if (err != LFS_ERR_OK)
+	{
+		/* LFS_ERR_IO / LFS_ERR_NOMEM 等：不格式化，避免破坏已有数据 */
+		printf("lfs: mount failed, err=%d (not formatted)\n", err);
+	}
+
+	if (err != LFS_ERR_OK)
+	{
+		g_lfs_ready = 0;
 		return;
+	}
+	g_lfs_ready = 1;
 #else
 	return;
 #endif

lua/lua.c

@@ -483,6 +483,91 @@ static int l_cat(lua_State *L)
     return 0;   /* 直接打印到终端，不再向 Lua 返回字符串 */
 }
 
+static int l_tail(lua_State *L)
+{
+    const char *path = luaL_optstring(L, 1, "C:rd.log");
+    long n = luaL_optinteger(L, 2, 15);
+
+    long start_off = 0;         /* 实际输出的起始偏移 */
+    long lines = 0;             /* 文件总行数 */
+
+    if (n > 0)
+    {
+        /* 环形缓冲：只保留最近最多 n 行的行首偏移 */
+        long *off = (long *)RD_MALLOC(sizeof(long) * (size_t)n);
+        if (off == NULL)
+        {
+            lua_print("tail: out of memory\n");
+            return 0;
+        }
+
+        void *fp = Rd_Fopen(path, "r");
+        if (fp == NULL)
+        {
+            RD_FREE(off);
+            lua_print("tail: cannot open '%s'\n", path);
+            return 0;
+        }
+
+        /* 第一遍：像 l_cat 一样用 Rd_Mread 分块读取，
+         * 手动按字节跟踪偏移并记录每行行首偏移（避免使用有问题的 Rd_Mgets） */
+        long pos = 0;               /* 当前已读到的文件偏移 */
+        int at_line_start = 1;      /* 当前位置是否是一行的开头 */
+        char buf[128];
+        ssize_t m;
+        while ((m = Rd_Mread(buf, sizeof(buf), fp)) > 0)
+        {
+            int i;
+            for (i = 0; i < (int)m; i++)
+            {
+                if (at_line_start)
+                {
+                    off[lines % n] = pos;   /* 记录本行行首偏移 */
+                    lines++;
+                    at_line_start = 0;
+                }
+                pos++;
+                if (buf[i] == '\n')
+                    at_line_start = 1;
+            }
+        }
+        Rd_Mclose(fp);
+
+        if (lines > 0)
+        {
+            long first = (lines <= n) ? 0 : (lines - n);
+            start_off = off[first % n];
+        }
+        RD_FREE(off);
+    }
+    else
+    {
+        return 0;               /* n <= 0 时不输出 */
+    }
+
+    /* 第二遍：从 start_off 重新打开并打印到文件末尾 */
+    void *fp = Rd_Fopen(path, "r");
+    if (fp == NULL)
+    {
+        lua_print("tail: cannot open '%s'\n", path);
+        return 0;
+    }
+    if (Rd_Mseek(fp, start_off, SEEK_SET) < 0)  /* Rd_Mseek 失败返回 -1 */
+    {
+        Rd_Mclose(fp);
+        return 0;
+    }
+
+    char buf[128];
+    ssize_t m;
+    while ((m = Rd_Mread(buf, sizeof(buf), fp)) > 0)
+    {
+        lua_print("%.*s", (int)m, buf);
+    }
+    Rd_Mclose(fp);
+    return 0;
+}
+
 static int l_mv(lua_State *L)
 {
     size_t len;
@@ -582,6 +667,7 @@ static int luaopen_default(lua_State *L)
     lua_register_help(L, "name", l_name, "Show build time");
 	lua_register_help(L, "echo", l_echo, "eg: echo(\"Hello\", \"C:a.txt\")");
     lua_register_help(L, "cat", l_cat, "eg: cat(\"C:a.txt\")");
+    lua_register_help(L, "tail", l_tail, "eg: tail(\"C:rd.log\")  tail(\"C:rd.log\", 30)");
     lua_register_help(L, "mv", l_mv, "eg: mv(\"C:a.txt\", \"C:b.txt\")");
     lua_register_help(L, "rm", l_rm, "eg: rm(\"C:a.txt\")");
     lua_register_help(L, "ls", l_ls, "eg: ls()");