Added statvfs API to get storage statistics

The API is as per posix standard, but does not provide stats for file/directory.
Stats buffer (block size, total block count, free block count) is filled for
entire mounted filesystem.

Author: Deepika

features/filesystem/FileSystem.cpp

@@ -51,6 +51,11 @@ int FileSystem::mkdir(const char *path, mode_t mode)
     return -ENOSYS;
 }
 
+int FileSystem::statvfs(const char *path, struct statvfs *buf)
+{
+    return -ENOSYS;
+}
+
 int FileSystem::file_sync(fs_file_t file)
 {
     return 0;

features/filesystem/FileSystem.h

@@ -109,6 +109,14 @@ class FileSystem : public FileSystemLike {
      */
     virtual int mkdir(const char *path, mode_t mode);
 
+    /** Store information about the mounted filesystem in a statvfs structure
+     *
+     *  @param path     The name of the file to find information about
+     *  @param buf      The stat buffer to write to
+     *  @return         0 on success, negative error code on failure
+     */
+     virtual int statvfs(const char *path, struct statvfs *buf);
+
 protected:
     friend class File;
     friend class Dir;
@@ -143,7 +151,7 @@ class FileSystem : public FileSystemLike {
      *
      *  @param file     File handle
      *  @param buffer   The buffer to write from
-     *  @param size     The number of bytes to write 
+     *  @param size     The number of bytes to write
      *  @return         The number of bytes written, negative error on failure
      */
     virtual ssize_t file_write(fs_file_t file, const void *buffer, size_t size) = 0;
@@ -240,7 +248,7 @@ class FileSystem : public FileSystemLike {
      */
     virtual void dir_rewind(fs_dir_t dir);
 
-    /** Get the sizeof the directory 
+    /** Get the sizeof the directory
      *
      *  @param dir      Dir handle
      *  @return         Number of files in the directory

features/filesystem/fat/FATFileSystem.cpp

@@ -442,6 +442,34 @@ int FATFileSystem::stat(const char *path, struct stat *st) {
     return 0;
 }
 
+int FATFileSystem::statvfs(const char *path, struct statvfs *buf) {
+
+    memset(buf, 0, sizeof(struct statvfs));
+    FATFS *fs;
+    DWORD fre_clust;
+
+    lock();
+    FRESULT res = f_getfree(_fsid, &fre_clust, &fs);
+    if (res != FR_OK) {
+        unlock();
+        return fat_error_remap(res);
+    }
+
+    buf->f_bsize = fs->ssize;
+    buf->f_frsize = fs->ssize;
+    buf->f_blocks = (fs->n_fatent - 2) * fs->csize;
+    buf->f_bfree = fre_clust * fs->csize;
+    buf->f_bavail = buf->f_bfree;
+#if FF_USE_LFN
+    buf->f_namemax = FF_LFN_BUF;
+#else
+    buf->f_namemax = FF_SFN_BUF;
+#endif
+
+    unlock();
+    return 0;
+}
+
 void FATFileSystem::lock() {
     _ffs_mutex->lock();
 }

features/filesystem/fat/FATFileSystem.h

@@ -43,7 +43,7 @@ class FATFileSystem : public FileSystem {
      */
     FATFileSystem(const char *name = NULL, BlockDevice *bd = NULL);
     virtual ~FATFileSystem();
-    
+
     /** Formats a logical drive, FDISK partitioning rule.
      *
      *  The block device to format should be mounted when this function is called.
@@ -57,7 +57,7 @@ class FATFileSystem : public FileSystem {
      *    cluster_size must be a multiple of the underlying device's allocation unit
      *    and is currently limited to a max of 32,768 bytes. If zero, a cluster size
      *    will be determined from the device's allocation unit. Defaults to zero.
-     *   
+     *
      *  @return         0 on success, negative error code on failure
      */
     static int format(BlockDevice *bd, bd_size_t cluster_size = 0);
@@ -139,6 +139,14 @@ class FATFileSystem : public FileSystem {
      */
     virtual int mkdir(const char *path, mode_t mode);
 
+    /** Store information about the mounted filesystem in a statvfs structure
+     *
+     *  @param path     The name of the file to find information about
+     *  @param buf      The stat buffer to write to
+     *  @return         0 on success, negative error code on failure
+     */
+     virtual int statvfs(const char *path, struct statvfs *buf);
+
 protected:
     /** Open a file on the filesystem
      *
@@ -170,7 +178,7 @@ class FATFileSystem : public FileSystem {
      *
      *  @param file     File handle
      *  @param buffer   The buffer to write from
-     *  @param len      The number of bytes to write 
+     *  @param len      The number of bytes to write
      *  @return         The number of bytes written, negative error on failure
      */
     virtual ssize_t file_write(fs_file_t file, const void *buffer, size_t len);
@@ -251,7 +259,7 @@ class FATFileSystem : public FileSystem {
      *  @param dir      Dir handle
      */
     virtual void dir_rewind(fs_dir_t dir);
-    
+
 private:
     FATFS _fs; // Work area (file system object) for logical drive
     char _fsid[sizeof("0:")];

features/filesystem/littlefs/LittleFileSystem.cpp

@@ -336,6 +336,9 @@ int LittleFileSystem::stat(const char *name, struct stat *st)
     return lfs_toerror(err);
 }
 
+int LittleFileSystem::statvfs(const char *path, struct statvfs *buf)
+{
+}
 
 ////// File operations //////
 int LittleFileSystem::file_open(fs_file_t *file, const char *path, int flags)

features/filesystem/littlefs/LittleFileSystem.h

@@ -143,6 +143,14 @@ class LittleFileSystem : public mbed::FileSystem {
      */
     virtual int mkdir(const char *path, mode_t mode);
 
+    /** Store information about the mounted filesystem in a statvfs structure
+     *
+     *  @param path     The name of the file to find information about
+     *  @param buf      The stat buffer to write to
+     *  @return         0 on success, negative error code on failure
+     */
+     virtual int statvfs(const char *path, struct statvfs *buf);
+
 protected:
     /** Open a file on the filesystem
      *

platform/FileSystemHandle.cpp

@@ -42,3 +42,8 @@ int FileSystemHandle::mkdir(const char *path, mode_t mode)
 {
     return -ENOSYS;
 }
+
+int FileSystemHandle::statvfs(const char *path, struct statvfs *buf)
+{
+    return -ENOSYS;
+}

platform/FileSystemHandle.h

@@ -94,6 +94,14 @@ class FileSystemHandle : private NonCopyable<FileSystemHandle> {
      *  @return         0 on success, negative error code on failure
      */
     virtual int mkdir(const char *path, mode_t mode);
+
+    /** Store information about the mounted filesystem in a statvfs structure
+     *
+     *  @param path     The name of the file to find information about
+     *  @param buf      The stat buffer to write to
+     *  @return         0 on success, negative error code on failure
+     */
+     virtual int statvfs(const char *path, struct statvfs *buf);
 };
 /**@}*/
 

platform/mbed_retarget.cpp

@@ -709,6 +709,23 @@ extern "C" int stat(const char *path, struct stat *st) {
     }
 }
 
+extern "C" int statvfs(const char *path, struct statvfs *buf) {
+    FilePath fp(path);
+    FileSystemHandle *fs = fp.fileSystem();
+    if (fs == NULL) {
+        errno = ENODEV;
+        return -1;
+    }
+
+    int err = fs->statvfs(fp.fileName(), buf);
+    if (err < 0) {
+        errno = -err;
+        return -1;
+    } else {
+        return 0;
+    }
+}
+
 #if defined(TOOLCHAIN_GCC)
 /* prevents the exception handling name demangling code getting pulled in */
 #include "mbed_error.h"

platform/mbed_retarget.h

@@ -28,15 +28,16 @@
 /* We can get the following standard types from sys/types for gcc, but we
  * need to define the types ourselves for the other compilers that normally
  * target embedded systems */
-typedef signed   int  ssize_t;  ///< Signed size type, usually encodes negative errors
-typedef signed   long off_t;    ///< Offset in a data stream
+typedef signed   int  ssize_t;     ///< Signed size type, usually encodes negative errors
+typedef signed   long off_t;       ///< Offset in a data stream
 #if defined(__ARMCC_VERSION) || !defined(__GNUC__)
 typedef unsigned int  mode_t;   ///< Mode for opening files
 typedef unsigned int  dev_t;    ///< Device ID type
 typedef unsigned long ino_t;    ///< File serial number
 typedef unsigned int  nlink_t;  ///< Number of links to a file
 typedef unsigned int  uid_t;    ///< User ID
 typedef unsigned int  gid_t;    ///< Group ID
+typedef unsigned long long fsblkcnt_t;  ///< Count of file system blocks
 #endif
 
 #define O_RDONLY 0      ///< Open for reading
@@ -62,7 +63,7 @@ typedef unsigned int  gid_t;    ///< Group ID
 /* DIR declarations must also be here */
 #if __cplusplus
 namespace mbed {
-    
+
 class FileHandle;
 class DirHandle;
 std::FILE *mbed_fdopen(FileHandle *fh, const char *mode);
@@ -415,10 +416,24 @@ struct stat {
     time_t    st_ctime;   ///< Time of last status change
 };
 
+struct statvfs {
+    unsigned long  f_bsize;    ///< Filesystem block size
+    unsigned long  f_frsize;   ///< Fragment size (block size)
+
+    fsblkcnt_t     f_blocks;   ///< Number of blocks
+    fsblkcnt_t     f_bfree;    ///< Number of free blocks
+    fsblkcnt_t     f_bavail;   ///< Number of free blocks for unprivileged users
+
+    unsigned long  f_fsid;     ///< Filesystem ID
+
+    unsigned long  f_namemax;  ///< Maximum filename length
+};
+
 #if __cplusplus
 extern "C" {
 #endif
     int stat(const char *path, struct stat *st);
+    int statvfs(const char *path, struct statvfs *buf);
 #if __cplusplus
 };
 #endif