fs/pesudofile: support pseudo-file operation

Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>

fs/inode/inode.h

@@ -418,6 +418,28 @@ int foreach_inode(foreach_inode_t handler, FAR void *arg);
 
 int dir_allocate(FAR struct file *filep, FAR const char *relpath);
 
+/****************************************************************************
+ * Name: pseudofile_create
+ *
+ * Description:
+ *   Create the pseudo-file with specified path and mode, and alloc inode
+ *   of this pseudo-file.
+ *
+ ****************************************************************************/
+
+int pseudofile_create(FAR struct inode **node, FAR const char *path,
+                      mode_t mode);
+
+/****************************************************************************
+ * Name: inode_is_pseudofile
+ *
+ * Description:
+ *    Check inode whether is a pseudo file.
+ *
+ ****************************************************************************/
+
+bool inode_is_pseudofile(FAR struct inode *inode);
+
 #undef EXTERN
 #if defined(__cplusplus)
 }

fs/vfs/Make.defs

@@ -25,7 +25,7 @@ CSRCS += fs_fchstat.c fs_fstat.c fs_fstatfs.c fs_ioctl.c fs_lseek.c
 CSRCS += fs_mkdir.c fs_open.c fs_poll.c fs_pread.c fs_pwrite.c fs_read.c
 CSRCS += fs_rename.c fs_rmdir.c fs_select.c fs_sendfile.c fs_stat.c
 CSRCS += fs_statfs.c fs_unlink.c fs_write.c fs_dir.c fs_fsync.c
-CSRCS += fs_truncate.c
+CSRCS += fs_truncate.c fs_pseudofile.c
 
 # Certain interfaces are not available if there is no mountpoint support
 

fs/vfs/fs_open.c

@@ -75,7 +75,7 @@ static int file_vopen(FAR struct file *filep, FAR const char *path,
 {
   struct inode_search_s desc;
   FAR struct inode *inode;
-#ifndef CONFIG_DISABLE_MOUNTPOINT
+#if !defined(CONFIG_DISABLE_MOUNTPOINT) || defined(CONFIG_PSEUDOFS_FILE)
   mode_t mode = 0666;
 #endif
   int ret;
@@ -104,12 +104,22 @@ static int file_vopen(FAR struct file *filep, FAR const char *path,
   ret = inode_find(&desc);
   if (ret < 0)
     {
-      /* "O_CREAT is not set and the named file does not exist.  Or, a
-       * directory component in pathname does not exist or is a dangling
-       * symbolic link."
-       */
+#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
+      if ((oflags & O_CREAT) != 0)
+        {
+          ret = pseudofile_create(&desc.node, path, mode);
+        }
+#endif
 
-      goto errout_with_search;
+      if (ret < 0)
+        {
+          /* "O_CREAT is not set and the named file does not exist.  Or, a
+           * directory component in pathname does not exist or is a dangling
+           * symbolic link."
+           */
+
+          goto errout_with_search;
+        }
     }
 
   /* Get the search results */

fs/vfs/fs_pseudofile.c

@@ -0,0 +1,454 @@
+/****************************************************************************
+ * fs/vfs/fs_pseudofile.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <limits.h>
+#include <fcntl.h>
+#include <sys/param.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/fs/fs.h>
+#include <nuttx/fs/ioctl.h>
+#include <nuttx/lib/math32.h>
+
+#include "inode/inode.h"
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+struct fs_pseudofile_s
+{
+  mutex_t lock;
+  uint8_t crefs;
+#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
+  bool unlinked;
+#endif
+  FAR char *content;
+};
+
+/****************************************************************************
+ * Private Functions Prototypes
+ ****************************************************************************/
+
+static int     pseudofile_open(FAR struct file *filep);
+static int     pseudofile_close(FAR struct file *filep);
+static ssize_t pseudofile_write(FAR struct file *filep,
+                                FAR const char *buffer, size_t buflen);
+static ssize_t pseudofile_read(FAR struct file *filep, FAR char *buffer,
+                               size_t buflen);
+static off_t   pseudofile_seek(FAR struct file *filep, off_t offset,
+                               int whence);
+static int     pseudofile_mmap(FAR struct file *filep,
+                               FAR struct mm_map_entry_s *map);
+static int     pseudofile_truncate(FAR struct file *filep, off_t length);
+#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
+static int     pseudofile_unlink(FAR struct inode *inode);
+#endif
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct file_operations g_pseudofile_ops =
+{
+  pseudofile_open,     /* open */
+  pseudofile_close,    /* close */
+  pseudofile_read,     /* read */
+  pseudofile_write,    /* write */
+  pseudofile_seek,     /* seek */
+  NULL,                /* ioctl */
+  pseudofile_mmap,     /* mmap */
+  pseudofile_truncate, /* truncate */
+  NULL,                /* poll */
+#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
+  pseudofile_unlink,   /* unlink */
+#endif
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static int pseudofile_open(FAR struct file *filep)
+{
+  FAR struct inode *node = filep->f_inode;
+  FAR struct fs_pseudofile_s *pf = node->i_private;
+  int ret;
+
+  ret = nxmutex_lock(&pf->lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  if (pf->crefs >= 255)
+    {
+      ret = -EMFILE;
+    }
+  else
+    {
+      pf->crefs += 1;
+      ret = OK;
+    }
+
+#ifdef CONFIG_PSEUDOFS_ATTRIBUTES
+  node->i_atime.tv_sec = time(NULL);
+#endif
+  nxmutex_unlock(&pf->lock);
+  return ret;
+}
+
+static void pseudofile_remove(FAR struct fs_pseudofile_s *pf)
+{
+  nxmutex_unlock(&pf->lock);
+  nxmutex_destroy(&pf->lock);
+  kmm_free(pf->content);
+  kmm_free(pf);
+}
+
+static int pseudofile_close(FAR struct file *filep)
+{
+  FAR struct inode *node = filep->f_inode;
+  FAR struct fs_pseudofile_s *pf = node->i_private;
+  int ret;
+
+  ret = nxmutex_lock(&pf->lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  pf->crefs--;
+#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
+  if (pf->crefs <= 0 && pf->unlinked)
+#else
+  if (pf->crefs <= 0)
+#endif
+    {
+      pseudofile_remove(pf);
+      return OK;
+    }
+
+  nxmutex_unlock(&pf->lock);
+  return OK;
+}
+
+static int pseudofile_expand(FAR struct inode *node,
+                             size_t size)
+{
+  FAR struct fs_pseudofile_s *pf = node->i_private;
+  FAR void *tmp;
+
+  if (pf->content && kmm_malloc_size(pf->content) >= size)
+    {
+      node->i_size = size;
+      return 0;
+    }
+
+  tmp = kmm_realloc(pf->content, 1 << LOG2_CEIL(size));
+  if (tmp == NULL)
+    {
+      return -ENOMEM;
+    }
+
+  pf->content = tmp;
+  node->i_size = size;
+  return 0;
+}
+
+static ssize_t pseudofile_write(FAR struct file *filep,
+                                FAR const char *buffer, size_t buflen)
+{
+  FAR struct inode *node = filep->f_inode;
+  FAR struct fs_pseudofile_s *pf = node->i_private;
+  int ret;
+
+  ret = nxmutex_lock(&pf->lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  if (filep->f_oflags & O_APPEND)
+    {
+      ret = pseudofile_expand(node, node->i_size + buflen);
+      if (ret < 0)
+        {
+          nxmutex_unlock(&pf->lock);
+          return ret;
+        }
+
+      filep->f_pos = node->i_size - buflen;
+    }
+  else
+    {
+      ret = pseudofile_expand(node, filep->f_pos + buflen);
+      if (ret < 0)
+        {
+          nxmutex_unlock(&pf->lock);
+          return ret;
+        }
+    }
+
+  memcpy(pf->content + filep->f_pos, buffer, buflen);
+  filep->f_pos += buflen;
+#ifdef CONFIG_PSEUDOFS_ATTRIBUTES
+  node->i_mtime.tv_sec = time(NULL);
+#endif
+
+  nxmutex_unlock(&pf->lock);
+  return buflen;
+}
+
+static ssize_t pseudofile_read(FAR struct file *filep, FAR char *buffer,
+                               size_t buflen)
+{
+  FAR struct inode *node = filep->f_inode;
+  FAR struct fs_pseudofile_s *pf = node->i_private;
+  int ret;
+
+  if (buffer == NULL || node->i_size < filep->f_pos)
+    {
+      return -EINVAL;
+    }
+
+  ret = nxmutex_lock(&pf->lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  buflen = MIN(node->i_size - filep->f_pos, buflen);
+  memcpy(buffer, pf->content + filep->f_pos, buflen);
+  filep->f_pos += buflen;
+
+#ifdef CONFIG_PSEUDOFS_ATTRIBUTES
+  node->i_atime.tv_sec = time(NULL);
+#endif
+  nxmutex_unlock(&pf->lock);
+
+  return buflen;
+}
+
+static off_t pseudofile_seek(FAR struct file *filep, off_t offset,
+                             int whence)
+{
+  FAR struct inode *node = filep->f_inode;
+  FAR struct fs_pseudofile_s *pf = node->i_private;
+  int ret;
+
+  ret = nxmutex_lock(&pf->lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  /* Map the offset according to the whence option */
+
+  switch (whence)
+    {
+      case SEEK_SET:
+          break;
+
+      case SEEK_CUR:
+          offset += filep->f_pos;
+          break;
+
+      case SEEK_END:
+          offset += node->i_size;
+          break;
+
+      default:
+          nxmutex_unlock(&pf->lock);
+          return -EINVAL;
+    }
+
+  if (offset < 0)
+    {
+      nxmutex_unlock(&pf->lock);
+      return -EINVAL;
+    }
+
+  filep->f_pos = offset;
+#ifdef CONFIG_PSEUDOFS_ATTRIBUTES
+  node->i_atime.tv_sec = time(NULL);
+#endif
+  nxmutex_unlock(&pf->lock);
+  return offset;
+}
+
+static int pseudofile_mmap(FAR struct file *filep,
+                           FAR struct mm_map_entry_s *map)
+{
+  FAR struct inode *node = filep->f_inode;
+  FAR struct fs_pseudofile_s *pf = node->i_private;
+
+  if (map->offset >= 0 && map->offset < node->i_size &&
+      map->length != 0 && map->offset + map->length <= node->i_size)
+    {
+      map->vaddr = pf->content + map->offset;
+      return OK;
+    }
+
+  return -EINVAL;
+}
+
+static int pseudofile_truncate(FAR struct file *filep, off_t length)
+{
+  FAR struct inode *node = filep->f_inode;
+  FAR struct fs_pseudofile_s *pf = node->i_private;
+  int ret;
+
+  ret = nxmutex_lock(&pf->lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  if (length < node->i_size)
+    {
+      FAR void *tmp;
+
+      tmp = kmm_realloc(pf->content, length);
+      if (tmp == NULL)
+        {
+          ret = -ENOMEM;
+          goto out;
+        }
+
+      pf->content = tmp;
+      node->i_size = length;
+    }
+  else
+    {
+      ret = pseudofile_expand(node, length);
+      if (ret < 0)
+        {
+          goto out;
+        }
+
+      memset(pf->content + node->i_size, 0, length - node->i_size);
+    }
+
+#ifdef CONFIG_PSEUDOFS_ATTRIBUTES
+  node->i_mtime.tv_sec = time(NULL);
+#endif
+
+out:
+  nxmutex_unlock(&pf->lock);
+  return ret;
+}
+
+#ifndef CONFIG_DISABLE_PSEUDOFS_OPERATIONS
+static int pseudofile_unlink(FAR struct inode *node)
+{
+  FAR struct fs_pseudofile_s *pf = node->i_private;
+  int ret;
+
+  ret = nxmutex_lock(&pf->lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  if (pf->crefs <= 0)
+    {
+      pseudofile_remove(pf);
+      return OK;
+    }
+
+  pf->unlinked = true;
+  nxmutex_unlock(&pf->lock);
+  return OK;
+}
+#endif
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: pseudofile_create
+ *
+ * Description:
+ *   Create the pseudo-file with specified path and mode, and alloc inode
+ *   of this pseudo-file.
+ *
+ ****************************************************************************/
+
+int pseudofile_create(FAR struct inode **node, FAR const char *path,
+                      mode_t mode)
+{
+  FAR struct fs_pseudofile_s *pf;
+  int ret;
+
+  if (node == NULL || path == NULL)
+    {
+      return -EINVAL;
+    }
+
+  pf = kmm_zalloc(sizeof(struct fs_pseudofile_s));
+  if (pf == NULL)
+    {
+      return -ENOMEM;
+    }
+
+  nxmutex_init(&pf->lock);
+
+  ret = inode_lock();
+  if (ret < 0)
+    {
+      nxmutex_destroy(&pf->lock);
+      kmm_free(pf);
+      return ret;
+    }
+
+  inode_reserve(path, mode, node);
+  (*node)->i_crefs = 0;
+  (*node)->i_flags = 1;
+  (*node)->u.i_ops = &g_pseudofile_ops;
+  (*node)->i_private = pf;
+
+  inode_unlock();
+
+  return 0;
+}
+
+/****************************************************************************
+ * Name: inode_is_pseudofile
+ *
+ * Description:
+ *    Check inode whether is a pseudo file.
+ *
+ ****************************************************************************/
+
+bool inode_is_pseudofile(FAR struct inode *inode)
+{
+  return inode != NULL && inode->u.i_ops == &g_pseudofile_ops;
+}

fs/vfs/fs_stat.c

@@ -416,7 +416,15 @@ int inode_stat(FAR struct inode *inode, FAR struct stat *buf, int resolve)
         {
           /* What is it if it also has child inodes? */
 
-          buf->st_mode |= S_IFCHR;
+          buf->st_size = inode->i_size;
+          if (inode_is_pseudofile(inode))
+            {
+              buf->st_mode |= S_IFREG;
+            }
+          else
+            {
+              buf->st_mode |= S_IFCHR;
+            }
         }
     }
   else

include/nuttx/fs/fs.h

@@ -405,6 +405,7 @@ struct inode
   uint16_t          i_flags;    /* Flags for inode */
   union inode_ops_u u;          /* Inode operations */
   ino_t             i_ino;      /* Inode serial number */
+  size_t            i_size;     /* The size of per inode driver */
 #ifdef CONFIG_PSEUDOFS_ATTRIBUTES
   mode_t            i_mode;     /* Access mode flags */
   uid_t             i_owner;    /* Owner */