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| <li class="toctree-l2"><a class="reference internal" href="../drivers/index.html">Device Drivers</a></li> |
| <li class="toctree-l2"><a class="reference internal" href="../nxflat.html">NXFLAT</a></li> |
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| <li class="toctree-l2"><a class="reference internal" href="../audio/index.html">Audio Subsystem</a></li> |
| <li class="toctree-l2 current"><a class="current reference internal" href="#">NuttX File System</a><ul> |
| <li class="toctree-l3"><a class="reference internal" href="#virtual-file-system-vfs">Virtual File System (VFS)</a><ul> |
| <li class="toctree-l4"><a class="reference internal" href="#how-vfs-works">How VFS works</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="#vfs-interface">VFS Interface</a></li> |
| </ul> |
| </li> |
| <li class="toctree-l3"><a class="reference internal" href="#file-systems">File systems</a><ul> |
| <li class="toctree-l4"><a class="reference internal" href="aio.html">Asynchronous I/O support</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="binfs.html">BINFS</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="cromfs.html">CROMFS</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="fat.html">FAT</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="hostfs.html">Host File System</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="littlefs.html">LITTLEFS</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="mmap.html">File mapping emulation (mmap)</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="mnemofs.html">MNEMOFS</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="nfs.html">NFS</a></li> |
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| <li class="toctree-l4"><a class="reference internal" href="partition.html">Partition Table</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="procfs.html">PROCFS</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="romfs.html">ROMFS</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="rpmsgfs.html">RPMSG File System</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="smartfs.html">SMARTFS</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="shmfs.html">Shared Memory File System</a></li> |
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| <li class="toctree-l4"><a class="reference internal" href="tmpfs.html">TMPFS</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="unionfs.html">Union File System</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="userfs.html">User file system</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="zipfs.html">ZipFS</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="inotify.html">Inotify</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="nuttxfs.html">Nuttx FS</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="nxflat.html">NuttX FLAT Binary Format (NXFLAT)</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="pseudofs.html">Pseudo File System</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="special_files_dev_num.html">Special Files and Device Numbers</a></li> |
| <li class="toctree-l4"><a class="reference internal" href="v9fs.html">V9FS</a></li> |
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| <li class="toctree-l4"><a class="reference internal" href="#fs-categories">FS Categories</a></li> |
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| <section id="nuttx-file-system"> |
| <h1>NuttX File System<a class="headerlink" href="#nuttx-file-system" title="Permalink to this heading"></a></h1> |
| <p>NuttX includes an optional, scalable file system. This file-system may be |
| omitted altogether; NuttX does not depend on the presence of any file system.</p> |
| <p id="root-fs"><strong>Pseudo Root File System</strong>. A simple <em>in-memory</em>, <em>pseudo</em> file |
| system can be enabled by default. This is an <em>in-memory</em> file |
| system because it does not require any storage medium or block |
| driver support. Rather, file system contents are generated |
| on-the-fly as referenced via standard file system operations |
| (open, close, read, write, etc.). In this sense, the file system |
| is <em>pseudo</em> file system (in the same sense that the Linux |
| <code class="docutils literal notranslate"><span class="pre">/proc</span></code> file system is also referred to as a pseudo file |
| system).</p> |
| <p>Any user supplied data or logic can be accessed via the |
| pseudo-file system. Built in support is provided for character and |
| block drivers in the <code class="docutils literal notranslate"><span class="pre">/dev</span></code> pseudo file system directory.</p> |
| <p><strong>Mounted File Systems</strong> The simple in-memory file system can be |
| extended my mounting block devices that provide access to true |
| file systems backed up via some mass storage device. NuttX |
| supports the standard <code class="docutils literal notranslate"><span class="pre">mount()</span></code> command that allows a block |
| driver to be bound to a mountpoint within the pseudo file system |
| and to a file system. At present, NuttX supports the standard VFAT |
| and ROMFS file systems, a special, wear-leveling NuttX FLASH File |
| System (NXFFS), as well as a Network File System client (NFS |
| version 3, UDP).</p> |
| <p><strong>Comparison to Linux</strong> From a programming perspective, the NuttX |
| file system appears very similar to a Linux file system. However, |
| there is a fundamental difference: The NuttX root file system is a |
| pseudo file system and true file systems may be mounted in the |
| pseudo file system. In the typical Linux installation by |
| comparison, the Linux root file system is a true file system and |
| pseudo file systems may be mounted in the true, root file system. |
| The approach selected by NuttX is intended to support greater |
| scalability from the very tiny platform to the moderate platform.</p> |
| <section id="virtual-file-system-vfs"> |
| <h2>Virtual File System (VFS)<a class="headerlink" href="#virtual-file-system-vfs" title="Permalink to this heading"></a></h2> |
| <p>Virtual File System provides a unified interface for various file systems to |
| be able to co-exist together by exposing a blueprint that each file system |
| needs to implement. This also allows the file system to be free from worry |
| about the device driver implementations for storage devices, as they also |
| expose a unified way of accessing the underlying devices.</p> |
| <section id="how-vfs-works"> |
| <h3>How VFS works<a class="headerlink" href="#how-vfs-works" title="Permalink to this heading"></a></h3> |
| <p>Threads are controllable sequences of instruction execution with their own |
| stacks. Each task in NuttX is represented by a Task Control Block (TCB) (TCB |
| is defined in <code class="docutils literal notranslate"><span class="pre">include/nuttx/sched.h</span></code>) and tasks are organized in task |
| lists.</p> |
| <p>All threads that are created by <code class="docutils literal notranslate"><span class="pre">pthread_create()</span></code> are part of the same task |
| group. A task group (defined in <code class="docutils literal notranslate"><span class="pre">include/nuttx/sched.h</span></code>) is a shared |
| structure pointed to by the TCBs of all the threads that belong to the same |
| task group, and this task group contains all the resources shared across the |
| task group which includes <em>file descriptors</em> in the form of a <strong>file list</strong>.</p> |
| <p>A file list (defined in <code class="docutils literal notranslate"><span class="pre">include/nuttx/fs/fs.h</span></code>) contains file structures |
| that denote open files (along with a spinlock to manage access to the file |
| list). With the devices listed in the <a class="reference internal" href="#root-fs"><span class="std std-ref">root file system</span></a> (on |
| points like <code class="docutils literal notranslate"><span class="pre">/dev/led</span></code>, <code class="docutils literal notranslate"><span class="pre">/dev/mmcsd0</span></code>, etc. which are henceforth called |
| blockdriver mount points) in an unmounted state, storage devices can be |
| mounted using the <code class="docutils literal notranslate"><span class="pre">mount()</span></code> command (to any point like <code class="docutils literal notranslate"><span class="pre">/dir/abcd</span></code>) with |
| any specific supported file system, which internally calls its implemented |
| <code class="docutils literal notranslate"><span class="pre">mountpt_operations->bind()</span></code> method and passes the blockdriver’s mount |
| point inode to it, thus creating a <strong>mount point</strong>. The blockdriver mount |
| point inode will have a <code class="docutils literal notranslate"><span class="pre">mountpt->i_private</span></code> which contains any (file system |
| dependent) information about the mount and is to be filled by the file system |
| during the execution of <code class="docutils literal notranslate"><span class="pre">mountpt_operations->bind()</span></code> (and usually this data |
| includes a pointer to the blockdriver mount point as well). After that, |
| according to system calls, the other exposed functions of the filesystem |
| are called as per need.</p> |
| </section> |
| <section id="vfs-interface"> |
| <h3>VFS Interface<a class="headerlink" href="#vfs-interface" title="Permalink to this heading"></a></h3> |
| <p>VFS allows file systems to expose their own implementations of methods |
| belonging to a unified interface:</p> |
| <ul class="simple"> |
| <li><p><strong>File operations</strong></p></li> |
| </ul> |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.open"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">open</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">relpath</span></span>, <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="n"><span class="pre">oflags</span></span>, <span class="n"><span class="pre">mode_t</span></span><span class="w"> </span><span class="n"><span class="pre">mode</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.open" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Opens a file. Files are required to be opened before any other file |
| operations are performed on it.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s file structure pointer. The |
| <code class="docutils literal notranslate"><span class="pre">filep->f_priv</span></code> member needs to be set here with the file system |
| specific data that represents an open file.</p></li> |
| <li><p><strong>relpath</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – Relative path of the file from the root of |
| the mounted file system.</p></li> |
| <li><p><strong>oflags</strong> (<span><span class="c-expr sig sig-inline c"><span class="kt">int</span></span></span>) – Flags in a bit field that specify the mode for opening |
| the file (eg. <code class="docutils literal notranslate"><span class="pre">O_RDONLY</span></code>, <code class="docutils literal notranslate"><span class="pre">O_RDWR</span></code>, etc. defined in |
| <code class="docutils literal notranslate"><span class="pre">include/fcntl.h</span></code>).</p></li> |
| <li><p><strong>mode</strong> (<span><span class="c-expr sig sig-inline c"><span class="n">mode_t</span></span></span>) – Specifies the mode (permissions). If <code class="docutils literal notranslate"><span class="pre">oflags</span></code> include |
| <code class="docutils literal notranslate"><span class="pre">O_CREAT</span></code>, then this contains the mode for the file to be created.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of opening a file.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.close"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">close</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.close" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>This closes the opened file, and ideally syncs all the changes to the file |
| to be written to the disk, as well as free the memory allocated to store the |
| open file’s data.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s file structure pointer.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of closing a file.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.read"> |
| <span class="n"><span class="pre">ssize_t</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">read</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buffer</span></span>, <a class="reference internal" href="../../reference/user/structures.html#c.size_t" title="size_t"><span class="n"><span class="pre">size_t</span></span></a><span class="w"> </span><span class="n"><span class="pre">buflen</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.read" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Reads maximum <code class="docutils literal notranslate"><span class="pre">buflen</span></code> bytes from an opened file (from the current offset |
| the opened file descriptor is pointing at if the file system supports |
| seeking).</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s file structure pointer.</p></li> |
| <li><p><strong>buffer</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – Buffer to store the read data.</p></li> |
| <li><p><strong>buflen</strong> (<span><span class="c-expr sig sig-inline c"><a class="reference internal" href="../../reference/user/structures.html#c.size_t" title="size_t"><span class="n">size_t</span></a></span></span>) – Length of the maximum number of bytes to be read.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Number of bytes read.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>> 0</strong> – Size of bytes read.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.write"> |
| <span class="n"><span class="pre">ssize_t</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">write</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buffer</span></span>, <a class="reference internal" href="../../reference/user/structures.html#c.size_t" title="size_t"><span class="n"><span class="pre">size_t</span></span></a><span class="w"> </span><span class="n"><span class="pre">buflen</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.write" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Writes maximum <code class="docutils literal notranslate"><span class="pre">buflen</span></code> bytes to an opened file (from the current offset |
| the opened file is at if the file system supports seeking).</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s file structure pointer.</p></li> |
| <li><p><strong>buffer</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – Buffer which contains the data to be written.</p></li> |
| <li><p><strong>buflen</strong> (<span><span class="c-expr sig sig-inline c"><a class="reference internal" href="../../reference/user/structures.html#c.size_t" title="size_t"><span class="n">size_t</span></a></span></span>) – Length of the maximum number of bytes to be written.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Number of bytes written.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>> 0</strong> – Size of bytes written.</p></li> |
| <li><p><strong>< buflen</strong> – Insufficient storage or file size limit reached</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <div class="admonition note"> |
| <p class="admonition-title">Note</p> |
| <p>POSIX requires that a <code class="docutils literal notranslate"><span class="pre">read()</span></code> after a <code class="docutils literal notranslate"><span class="pre">write()</span></code> should get the newly |
| written data, but not all file systems conform to POSIX, especially as |
| POSIX requires atomic writes, which is not usually implemented |
| as it can impact performance.</p> |
| <p>To be POSIX compliant in concurrent situations, either the writes have to |
| be atomic, or read is blocked with a lock until an on-going write is |
| finished, which, as stated, would impact performance.</p> |
| </div> |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.seek"> |
| <span class="n"><span class="pre">off_t</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">seek</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span>, <span class="n"><span class="pre">off_t</span></span><span class="w"> </span><span class="n"><span class="pre">offset</span></span>, <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="n"><span class="pre">whence</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.seek" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Underlying implementation of <code class="docutils literal notranslate"><span class="pre">lseek()</span></code>, it allows the open file’s file |
| structure to point to any particular location in the file.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s file structure pointer.</p></li> |
| <li><p><strong>offset</strong> (<span><span class="c-expr sig sig-inline c"><span class="n">off_t</span></span></span>) – The offset required.</p></li> |
| <li><p><strong>whence</strong> (<span><span class="c-expr sig sig-inline c"><span class="kt">int</span></span></span>) – <p>This controls how the offset it applied. It can have |
| values (defined in <code class="docutils literal notranslate"><span class="pre">/include/sys/types.h</span></code>):</p> |
| <ul> |
| <li><p>SEEK_SET: Offset from start of file.</p></li> |
| <li><p>SEEK_CUR: Offset from current location in file.</p></li> |
| <li><p>SEEK_END: Offset <em>after</em> end of file.</p></li> |
| </ul> |
| </p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <div class="admonition note"> |
| <p class="admonition-title">Note</p> |
| <p>According to POSIX, <code class="docutils literal notranslate"><span class="pre">lseek()</span></code> to any point after the end of the file |
| <em>does not</em> by itself increase the size of the file. Later writes to this |
| part will, however, increase it to at least the end of the written data, and |
| the “gap” before this written data should be filled with <code class="docutils literal notranslate"><span class="pre">\0</span></code> in case of |
| any reads after such a write operation.</p> |
| </div> |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.ioctl"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">ioctl</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span>, <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="n"><span class="pre">cmd</span></span>, <span class="kt"><span class="pre">unsigned</span></span><span class="w"> </span><span class="kt"><span class="pre">long</span></span><span class="w"> </span><span class="n"><span class="pre">arg</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.ioctl" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>It is the underlying implementation of <code class="docutils literal notranslate"><span class="pre">ioctl()</span></code> (I/O Control). |
| <code class="docutils literal notranslate"><span class="pre">ioctl()</span></code> manipulates the underlying device parameters of files.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s file structure pointer.</p></li> |
| <li><p><strong>cmd</strong> (<span><span class="c-expr sig sig-inline c"><span class="kt">int</span></span></span>) – It can take a variety of values (which are defined in |
| <code class="docutils literal notranslate"><span class="pre">include/nuttx/fs/ioctl.h</span></code>). It represents the command that will be |
| carried out on the file. Both the filesystem, as well as the device driver |
| needs to support the command in order for the function to run.</p></li> |
| <li><p><strong>arg</strong> (<span><span class="c-expr sig sig-inline c"><span class="kt">unsigned</span><span class="w"> </span><span class="kt">long</span></span></span>) – Additional argument that may be required for |
| ioctl. Details for what is required is written in the comments beside |
| the desired ioctl command in <code class="docutils literal notranslate"><span class="pre">include/nuttx/fs/ioctl.h</span></code>.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of ioctl operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.mmap"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">mmap</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">mm_map_entry_s</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">map</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.mmap" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Underlying implementation of <code class="docutils literal notranslate"><span class="pre">mmap()</span></code>. <code class="docutils literal notranslate"><span class="pre">mmap()</span></code> creates a new mapping |
| in the virtual address space of the calling process.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s file structure pointer.</p></li> |
| <li><p><strong>map</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">mm_map_entry_s</span><span class="p">*</span></span></span>) – mmap entry structure pointer, which |
| includes the virtual address.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of mmap operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <div class="admonition note"> |
| <p class="admonition-title">Note</p> |
| <p>NuttX operates in a flat open address space. Therefore, it generally does |
| not require <code class="docutils literal notranslate"><span class="pre">mmap()</span></code> functionality. There are two notable exceptions where |
| <code class="docutils literal notranslate"><span class="pre">mmap()</span></code> functionality is required:</p> |
| <ol class="arabic simple"> |
| <li><p><code class="docutils literal notranslate"><span class="pre">mmap()</span></code> is the API that is used to support direct access to random |
| access media under the following very restrictive conditions:</p></li> |
| </ol> |
| <blockquote> |
| <div><ol class="loweralpha simple"> |
| <li><p>The filesystem implements the mmap file operation. Any file |
| system that maps files contiguously on the media should support |
| this ioctl. (vs. file system that scatter files over the media |
| in non-contiguous sectors). As of this writing, ROMFS is the |
| only file system that meets this requirement.</p></li> |
| <li><p>The underlying block driver supports the BIOC_XIPBASE ioctl |
| command that maps the underlying media to a randomly accessible |
| address. At present, only the RAM/ROM disk driver does this.</p></li> |
| </ol> |
| </div></blockquote> |
| <ol class="arabic simple" start="2"> |
| <li><p>If CONFIG_FS_RAMMAP is defined in the configuration, then mmap() will |
| support simulation of memory mapped files by copying files whole |
| into RAM.</p></li> |
| </ol> |
| </div> |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.truncate"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">truncate</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span>, <span class="n"><span class="pre">off_t</span></span><span class="w"> </span><span class="n"><span class="pre">length</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.truncate" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Shrinks or expands the file to be of the desired size.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s file structure pointer.</p></li> |
| <li><p><strong>length</strong> (<span><span class="c-expr sig sig-inline c"><span class="n">off_t</span></span></span>) – Final size of the file.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of truncate operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.poll"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">poll</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">pollfd</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">fds</span></span>, <span class="kt"><span class="pre">bool</span></span><span class="w"> </span><span class="n"><span class="pre">setup</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.poll" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Underlying implementation of <code class="docutils literal notranslate"><span class="pre">poll()</span></code>. The <code class="docutils literal notranslate"><span class="pre">poll()</span></code> function provides |
| applications with a mechanism for multiplexing input/output over a set of |
| file descriptors.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s pointer.</p></li> |
| <li><p><strong>fds</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">pollfd</span><span class="p">*</span></span></span>) – The structure describing the events to be |
| monitored, OR NULL if this is a request to stop monitoring events.</p></li> |
| <li><p><strong>setup</strong> (<span><span class="c-expr sig sig-inline c"><span class="kt">bool</span></span></span>) – true: Setup up the poll; false: Teardown the poll</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of poll operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <ul class="simple"> |
| <li><p><strong>Additional open file specific operations</strong></p></li> |
| </ul> |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.sync"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">sync</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.sync" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>This synchronizes the on-disk file system state of the file with the |
| in-memory file system state, ie. commits the file system caches to the disk.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s <code class="docutils literal notranslate"><span class="pre">struct</span> <span class="pre">file</span></code> (defined in |
| <code class="docutils literal notranslate"><span class="pre">include/nuttx/fs/fs.h</span></code>) pointer.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of syncing a file.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.dup"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">dup</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">oldp</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">newp</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.dup" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Duplicate an open file structure.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>oldp</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Pointer to structure that is to be |
| duplicated.</p></li> |
| <li><p><strong>newp</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Pointer to structure in which the duplicate |
| data will be stored.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of duplicating open file’s structure.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.fstat"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">fstat</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.stat" title="stat"><span class="n"><span class="pre">stat</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buf</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.fstat" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Obtain information about an open file.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s pointer.</p></li> |
| <li><p><strong>buf</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><a class="reference internal" href="#c.stat" title="stat"><span class="n">stat</span></a><span class="p">*</span></span></span>) – Pointer to the <code class="docutils literal notranslate"><span class="pre">struct</span> <span class="pre">stat</span></code> (defined in |
| <code class="docutils literal notranslate"><span class="pre">include/sys/stat.h</span></code>).</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of obtaining open file’s information.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.fchstat"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">fchstat</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">file</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">filep</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.stat" title="stat"><span class="n"><span class="pre">stat</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buf</span></span>, <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="n"><span class="pre">flags</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.fchstat" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Change file stats. It can change the mode, timestamps and ownership.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>filep</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">file</span><span class="p">*</span></span></span>) – Open file’s pointer.</p></li> |
| <li><p><strong>buf</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="k">struct</span><span class="w"> </span><a class="reference internal" href="#c.stat" title="stat"><span class="n">stat</span></a><span class="p">*</span></span></span>) – Pointer to stat structure describing |
| the values that need to be updated.</p></li> |
| <li><p><strong>flags</strong> (<span><span class="c-expr sig sig-inline c"><span class="kt">int</span></span></span>) – <p>Bit field that can include (defined in |
| <code class="docutils literal notranslate"><span class="pre">include/nuttx/fs/fs.h</span></code>):</p> |
| <ul> |
| <li><p><code class="docutils literal notranslate"><span class="pre">CH_STAT_MODE</span></code></p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">CH_STAT_UID</span></code></p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">CH_STAT_GID</span></code></p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">CH_STAT_ATIME</span></code></p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">CH_STAT_MTIME</span></code></p></li> |
| </ul> |
| <p>This describes what needs to be updated.</p> |
| </p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of changing open file’s stats.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <ul class="simple"> |
| <li><p><strong>Directory operations</strong></p></li> |
| </ul> |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.opendir"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">opendir</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">relpath</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">fs_dirent_s</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">dir</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.opendir" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Opens a directory stream for the provided directory. Other directory |
| operations can be used after this to do various directory related operations |
| . We say the directory stream points to the first entry, but you need |
| <code class="docutils literal notranslate"><span class="pre">readdir()</span></code> to read the first entry.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>relpath</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – Relative path from the root of the point |
| point of the directory.</p></li> |
| <li><p><strong>dir</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">fs_dirent_s</span><span class="p">*</span><span class="p">*</span></span></span>) – A directory stream structure pointer |
| which needs to be populated with the required fields (defined in |
| <code class="docutils literal notranslate"><span class="pre">include/nuttx/fs/fs.h</span></code>).</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of opening the directory.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.closedir"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">closedir</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">fs_dirent_s</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">dir</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.closedir" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Closes a directory stream, as well as deallocates any memory used while |
| while opening a directory stream.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>dir</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">fs_dirent_s</span><span class="p">*</span><span class="p">*</span></span></span>) – A directory stream structure pointer |
| which was previously allocated (and needs to be freed).</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of closing the directory.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><p><strong>OK (0)</strong> – Success.</p> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.readdir"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">readdir</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">fs_dirent_s</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">dir</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">dirent</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">entry</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.readdir" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>This reads the next directory entry in a directory stream. If the stream |
| points to the base of the directory, then the first directory entry in the |
| directory is given.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>dir</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">fs_dirent_s</span><span class="p">*</span><span class="p">*</span></span></span>) – A directory stream structure pointer.</p></li> |
| <li><p><strong>entry</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">dirent</span><span class="p">*</span></span></span>) – Pointer to the directory entry. This will |
| be modified to point to the directory entry after it in the directory.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of reading the directory.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.rewinddir"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">rewinddir</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">fs_dirent_s</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">dir</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.rewinddir" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Resets the directory stream back to the first entry, like it was after |
| opening.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>dir</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">fs_dirent_s</span><span class="p">*</span><span class="p">*</span></span></span>) – A directory stream structure pointer.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of rewinding the directory.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <ul class="simple"> |
| <li><p><strong>Volume-relations operations</strong></p></li> |
| </ul> |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.bind"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">bind</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">blkdriver</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">data</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">handle</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.bind" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>This is where the file system related data is initialized, and |
| is part of the mount process.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>blkdriver</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Pointer to the block driver’s device |
| inode. This needs to be opened in this function.</p></li> |
| <li><p><strong>data</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">void</span><span class="p">*</span></span></span>) – The options provided during mount.</p></li> |
| <li><p><strong>handle</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="kt">void</span><span class="p">*</span><span class="p">*</span></span></span>) – Whatever data <code class="docutils literal notranslate"><span class="pre">handle</span></code> points to is attached |
| to the <code class="docutils literal notranslate"><span class="pre">mountpt</span></code> inode after this function is called during the mount |
| process. This way, this file system’s other methods can receive |
| this information if they have access to <code class="docutils literal notranslate"><span class="pre">mountpt</span></code> inode, by accessing |
| <code class="docutils literal notranslate"><span class="pre">mountpt->i_private</span></code>.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of binding operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.unbind"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">unbind</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">handle</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">blkdriver</span></span>, <span class="kt"><span class="pre">unsigned</span></span><span class="w"> </span><span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="n"><span class="pre">flags</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.unbind" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>This is part of the unmounting process. The file system first |
| needs to assess the flags passed to it and appropriately do the tasks |
| required by these flags, and then it needs to free the private data |
| (<code class="docutils literal notranslate"><span class="pre">handle</span></code> and any allocated members), as well as close the |
| previously-opened (during mount) block driver’s inode.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>handle</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="kt">void</span><span class="p">*</span></span></span>) – Private data of the file-system.</p></li> |
| <li><p><strong>blkdriver</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span><span class="p">*</span></span></span>) – The device inode of the block driver’s |
| device inode.</p></li> |
| <li><p><strong>flags</strong> (<span><span class="c-expr sig sig-inline c"><span class="kt">unsigned</span><span class="w"> </span><span class="kt">int</span></span></span>) – <p>Flags dictate the actions needed to be carried |
| out before the file system data is removed and the block driver inode is |
| closed. The values can be (as defined in <code class="docutils literal notranslate"><span class="pre">include/sys/mount.h</span></code>):</p> |
| <ul> |
| <li><p><code class="docutils literal notranslate"><span class="pre">MNT_FORCE</span></code></p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">MNT_DETACH</span></code></p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">MNT_EXPIRE</span></code></p></li> |
| <li><p><code class="docutils literal notranslate"><span class="pre">UMOUNT_NOFOLLOW</span></code></p></li> |
| </ul> |
| </p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of unbinding operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.statfs"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">statfs</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.statfs" title="statfs"><span class="n"><span class="pre">statfs</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buf</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.statfs" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Provides stats for that instance of the file system. The exact |
| stats that are provided can be viewed in the members of |
| <code class="docutils literal notranslate"><span class="pre">struct</span> <span class="pre">statfs</span></code> (in file <code class="docutils literal notranslate"><span class="pre">include/sys/statfs.h</span></code>).</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>buf</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><a class="reference internal" href="#c.statfs" title="statfs"><span class="n">statfs</span></a><span class="p">*</span></span></span>) – Buffer that needs to be filled with the |
| relevant file system information.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of finding the filesystem stats operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <ul class="simple"> |
| <li><p><strong>Path operations</strong></p></li> |
| </ul> |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.unlink"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">unlink</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">relpath</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.unlink" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Removes a file, specifically, removes a name from the file system.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>relpath</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – The relative path of the file from the root |
| of the file system.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of unlinking operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.mkdir"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">mkdir</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">relpath</span></span>, <span class="n"><span class="pre">mode_t</span></span><span class="w"> </span><span class="n"><span class="pre">mode</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.mkdir" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Creates a directory.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>relpath</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – Relative path of the new directory from the |
| root of the file system.</p></li> |
| <li><p><strong>mode</strong> (<span><span class="c-expr sig sig-inline c"><span class="n">mode_t</span></span></span>) – The mode (permissions) for the directory.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of creating a directory operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.rmdir"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">rmdir</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">relpath</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.rmdir" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Removes a directory.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>relpath</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – Relative path of the directory from the |
| root of the file system.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of removing a directory operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.rename"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">rename</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">oldrelpath</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">newrelpath</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.rename" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Renames a file or a directory</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>oldrelpath</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – Existing path of the file or directory.</p></li> |
| <li><p><strong>newrelpath</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – New path of the file or directory.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of renaming a file or a directory operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.stat"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">stat</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">relpath</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.stat" title="stat"><span class="n"><span class="pre">stat</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buf</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.stat" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Information about a file or a directory. The exact information that is |
| provided can be viewed in the members of <code class="docutils literal notranslate"><span class="pre">struct</span> <span class="pre">stat</span></code> |
| (in file <code class="docutils literal notranslate"><span class="pre">include/sys/stat.h</span></code>).</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>relpath</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – Relative path of the file or directory from |
| the root of the file system.</p></li> |
| <li><p><strong>buf</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><a class="reference internal" href="#c.stat" title="stat"><span class="n">stat</span></a><span class="p">*</span></span></span>) – Buffer that needs to be filled with the |
| relevant file or directory information.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of finding information about a file or directory.1 operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.chstat"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">chstat</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="kt"><span class="pre">char</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">relpath</span></span>, <span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">const</span></span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="#c.stat" title="stat"><span class="n"><span class="pre">stat</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">buf</span></span>, <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="n"><span class="pre">flags</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.chstat" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>Change the stats of a file or directory.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| <li><p><strong>relpath</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="kt">char</span><span class="p">*</span></span></span>) – Relative path of the file or directory from |
| the root of the file system.</p></li> |
| <li><p><strong>buf</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">const</span><span class="w"> </span><span class="k">struct</span><span class="w"> </span><a class="reference internal" href="#c.stat" title="stat"><span class="n">stat</span></a><span class="p">*</span></span></span>) – Contains the new stat information. Access |
| only the ones that are required according to the flags.</p></li> |
| <li><p><strong>flags</strong> (<span><span class="c-expr sig sig-inline c"><span class="kt">int</span></span></span>) – A bit field that can have values including <code class="docutils literal notranslate"><span class="pre">CH_STAT_MODE</span></code> |
| , <code class="docutils literal notranslate"><span class="pre">CH_STAT_UID</span></code>, <code class="docutils literal notranslate"><span class="pre">CH_STAT_GID</span></code>, <code class="docutils literal notranslate"><span class="pre">CH_STAT_ATIME</span></code> or <code class="docutils literal notranslate"><span class="pre">CH_STAT_MTIME</span></code> |
| which are or-ed together.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <dl class="c function"> |
| <dt class="sig sig-object c" id="c.syncfs"> |
| <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">syncfs</span></span></span><span class="sig-paren">(</span><span class="pre">FAR</span><span class="w"> </span><span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">inode</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">mountpt</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.syncfs" title="Permalink to this definition"></a><br /></dt> |
| <dd><p>This works like <code class="docutils literal notranslate"><span class="pre">sync()</span></code> but instead of the file, it syncs the entire |
| filesystem’s metadata.</p> |
| <dl class="field-list simple"> |
| <dt class="field-odd">Parameters<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>mountpt</strong> (<span><span class="c-expr sig sig-inline c">FAR<span class="w"> </span><span class="k">struct</span><span class="w"> </span><span class="n">inode</span><span class="p">*</span></span></span>) – Mount point inode of the file system.</p></li> |
| </ul> |
| </dd> |
| <dt class="field-even">Returns<span class="colon">:</span></dt> |
| <dd class="field-even"><p>Status of syncing file system metadata operation.</p> |
| </dd> |
| <dt class="field-odd">Return values<span class="colon">:</span></dt> |
| <dd class="field-odd"><ul class="simple"> |
| <li><p><strong>OK (0)</strong> – Success.</p></li> |
| <li><p><strong>< 0</strong> – Error.</p></li> |
| </ul> |
| </dd> |
| </dl> |
| </dd></dl> |
| |
| <p>The file systems can have their own implementations for these functions |
| under-the-hood, but the user does not have to worry about the underlying file |
| system during file I/O, as the file system has to expose its implementations |
| in a unified interface.</p> |
| <div class="admonition note"> |
| <p class="admonition-title">Note</p> |
| <p>Each file system has to globally expose their implementations of the unified |
| interface as defined by <code class="docutils literal notranslate"><span class="pre">struct</span> <span class="pre">mountpt_operations</span></code> (in |
| <code class="docutils literal notranslate"><span class="pre">include/fs/fs.h</span></code>) to one of the lists defined in <code class="docutils literal notranslate"><span class="pre">fs/mount/fs_mount.c</span></code> |
| depending on the type of the file system.</p> |
| <p>They also need their own <a class="reference external" href="https://en.wikipedia.org/wiki/Magic_number_(programming)">magic number</a> |
| to be listed in <code class="docutils literal notranslate"><span class="pre">include/sys</span></code> and in <code class="docutils literal notranslate"><span class="pre">fs_gettype</span></code> function (in |
| <code class="docutils literal notranslate"><span class="pre">fs/mount/fs_gettype.c</span></code>) for identification of the filesystem.</p> |
| </div> |
| </section> |
| </section> |
| <section id="file-systems"> |
| <h2>File systems<a class="headerlink" href="#file-systems" title="Permalink to this heading"></a></h2> |
| <p>NuttX provides support for a variety of file systems out of the box.</p> |
| <div class="toctree-wrapper compound"> |
| <ul> |
| <li class="toctree-l1"><a class="reference internal" href="aio.html">Asynchronous I/O support</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="binfs.html">BINFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="cromfs.html">CROMFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="fat.html">FAT</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="hostfs.html">Host File System</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="littlefs.html">LITTLEFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="mmap.html">File mapping emulation (mmap)</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="mnemofs.html">MNEMOFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="nfs.html">NFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="nxffs.html">NXFFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="partition.html">Partition Table</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="procfs.html">PROCFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="romfs.html">ROMFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="rpmsgfs.html">RPMSG File System</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="smartfs.html">SMARTFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="shmfs.html">Shared Memory File System</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="spiffs.html">SPIFFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="tmpfs.html">TMPFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="unionfs.html">Union File System</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="userfs.html">User file system</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="zipfs.html">ZipFS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="inotify.html">Inotify</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="nuttxfs.html">Nuttx FS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="nxflat.html">NuttX FLAT Binary Format (NXFLAT)</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="pseudofs.html">Pseudo File System</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="special_files_dev_num.html">Special Files and Device Numbers</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="v9fs.html">V9FS</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="v9fs.html#adding-v9fs-to-the-nuttx-configuration">Adding V9FS to the NuttX Configuration</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="v9fs.html#nfs-mount-command">NFS Mount Command</a></li> |
| </ul> |
| </div> |
| <section id="fs-categories"> |
| <h3>FS Categories<a class="headerlink" href="#fs-categories" title="Permalink to this heading"></a></h3> |
| <p>File systems can be divided into these categories on the basis of the drivers |
| they require:</p> |
| <ol class="arabic simple"> |
| <li><p>They require a block device driver. They include vfat, romfs, smartfs, and |
| littlefs.</p></li> |
| <li><p>They require MTD drivers. They include romfs, spiffs, littlefs.</p></li> |
| <li><p>They require neither block nor MTD drivers. They include nxffs, tmpfs, nfs |
| binfs, procfs, userfs, hostfs, cromfs, unionfs, rpmsgfs, and zipfs.</p></li> |
| </ol> |
| <p>The requirements are specified by declaring the filesystem in the proper |
| array in <code class="docutils literal notranslate"><span class="pre">fs/mount/fs_mount.c</span></code>.</p> |
| </section> |
| </section> |
| </section> |
| |
| |
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