C Library: Add a very limited, first step implementation of setvbuf(). This is a collaborative effort. Alan Carvalho de Assis did the initial prototype.

fs/vfs/fs_stat.c

@@ -66,6 +66,14 @@
 #  define RESET_BUF(b) memset((b), 0, sizeof(struct stat));
 #endif
 
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static inline int statpseudo(FAR struct inode *inode, FAR struct stat *buf);
+static inline int statroot(FAR struct stat *buf);
+int stat_recursive(FAR const char *path, FAR struct stat *buf);
+
 /****************************************************************************
  * Private Functions
  ****************************************************************************/
@@ -129,7 +137,7 @@ static inline int statpseudo(FAR struct inode *inode, FAR struct stat *buf)
               return -ELOOP;
             }
 
-          DEBUGASSERT(buff->st_count > 0);  /* Check for unsigned integer overflow */
+          DEBUGASSERT(buf->st_count > 0);  /* Check for unsigned integer overflow */
 
           /* stat() the target of the soft link. */
 
@@ -307,8 +315,6 @@ errout_with_inode:
 
 errout_with_search:
   RELEASE_SEARCH(&desc);
-
-errout:
   set_errno(ret);
   return ERROR;
 }

include/nuttx/fs/fs.h

@@ -65,6 +65,7 @@
 
 #define __FS_FLAG_EOF   (1 << 0) /* EOF detected by a read operation */
 #define __FS_FLAG_ERROR (1 << 1) /* Error detected by any operation */
+#define __FS_FLAG_UBF   (1 << 2) /* Buffer allocated by caller of setvbuf */
 
 /* Inode i_flag values:
  *

include/stdio.h

@@ -64,15 +64,21 @@
 #  define BUFSIZ CONFIG_STDIO_BUFFER_SIZE
 #endif
 
+/* The following three definitions are for ANSI C, used by setvbuf */
+
+#define _IOFBF     0               /* Fully buffered */
+#define _IOLBF     1               /* Line buffered */
+#define _IONBF     2               /* Unbuffered */
+
 /* File system error values */
 
 #define EOF        (-1)
 
 /* The first three _iob entries are reserved for standard I/O */
 
-#define stdin  (&sched_getstreams()->sl_streams[0])
+#define stdin      (&sched_getstreams()->sl_streams[0])
-#define stdout (&sched_getstreams()->sl_streams[1])
+#define stdout     (&sched_getstreams()->sl_streams[1])
-#define stderr (&sched_getstreams()->sl_streams[2])
+#define stderr     (&sched_getstreams()->sl_streams[2])
 
 /* These APIs are not implemented and/or can be synthesized from
  * supported APIs.
@@ -90,7 +96,7 @@
 #  define CONFIG_LIBC_TMPDIR "/tmp"
 #endif
 
-#define P_tmpdir CONFIG_LIBC_TMPDIR
+#define P_tmpdir   CONFIG_LIBC_TMPDIR
 
 /* Maximum size of character array to hold tmpnam() output. */
 
@@ -98,7 +104,7 @@
 #  define CONFIG_LIBC_MAX_TMPFILE 32
 #endif
 
-#define L_tmpnam CONFIG_LIBC_MAX_TMPFILE
+#define L_tmpnam   CONFIG_LIBC_MAX_TMPFILE
 
 /* The maximum number of unique temporary file names that can be generated */
 
@@ -156,6 +162,7 @@ size_t fwrite(FAR const void *ptr, size_t size, size_t n_items,
          FAR FILE *stream);
 FAR char *gets(FAR char *s);
 FAR char *gets_s(FAR char *s, rsize_t n);
+int    setvbuf(FAR FILE *stream, FAR char *buffer, int mode, size_t size);
 int    ungetc(int c, FAR FILE *stream);
 
 /* Operations on the stdout stream, buffers, paths, and the whole printf-family */

libc/misc/lib_stream.c

@@ -53,18 +53,6 @@
 #if (!defined(CONFIG_BUILD_PROTECTED) && !defined(CONFIG_BUILD_KERNEL)) || \
       defined(__KERNEL__)
 
-/****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
-
-/****************************************************************************
- * Private Data
- ****************************************************************************/
-
-/****************************************************************************
- * Private Functions
- ****************************************************************************/
-
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -101,13 +89,15 @@ void lib_stream_initialize(FAR struct task_group_s *group)
 
   for (i = 0; i < CONFIG_NFILE_STREAMS; i++)
    {
-     /* Clear the IOB */
+      FAR struct file_struct *stream = &list->sl_streams[i];
 
-      memset(&list->sl_streams[i], 0, sizeof(FILE));
+      /* Clear the IOB */
+
+      memset(stream, 0, sizeof(FILE));
 
       /* Indicate not opened */
 
-      list->sl_streams[i].fs_fd = -1;
+      stream->fs_fd = -1;
 
       /* Initialize the stream semaphore to one to support one-at-
        * a-time access to private data sets.
@@ -154,18 +144,21 @@ void lib_stream_release(FAR struct task_group_s *group)
 #if CONFIG_STDIO_BUFFER_SIZE > 0
   for (i = 0; i < CONFIG_NFILE_STREAMS; i++)
     {
+      FAR struct file_struct *stream = &list->sl_streams[i];
+
       /* Destroy the semaphore that protects the IO buffer */
 
-      (void)sem_destroy(&list->sl_streams[i].fs_sem);
+      (void)sem_destroy(&stream->fs_sem);
 
       /* Release the IO buffer */
 
-      if (list->sl_streams[i].fs_bufstart)
+      if (stream->fs_bufstart != NULL &&
+          (stream->fs_flags & __FS_FLAG_UBF) == 0)
         {
 #ifndef CONFIG_BUILD_KERNEL
           /* Release memory from the user heap */
 
-          sched_ufree(list->sl_streams[i].fs_bufstart);
+          sched_ufree(stream->fs_bufstart);
 #else
           /* If the exiting group is unprivileged, then it has an address
            * environment.  Don't bother to release the memory in this case...
@@ -177,7 +170,7 @@ void lib_stream_release(FAR struct task_group_s *group)
 
           if ((group->tg_flags & GROUP_FLAG_PRIVILEGED) != 0)
             {
-              sched_kfree(list->sl_streams[i].fs_bufstart);
+              sched_kfree(stream->fs_bufstart);
             }
 #endif
         }

libc/stdio/Make.defs

@@ -65,7 +65,7 @@ CSRCS += lib_rdflush.c lib_wrflush.c lib_fputc.c lib_puts.c lib_fputs.c
 CSRCS += lib_ungetc.c lib_vprintf.c lib_fprintf.c lib_vfprintf.c
 CSRCS += lib_stdinstream.c lib_stdoutstream.c lib_stdsistream.c
 CSRCS += lib_stdsostream.c lib_perror.c lib_feof.c lib_ferror.c
-CSRCS += lib_clearerr.c
+CSRCS += lib_clearerr.c lib_setvbuf.c
 
 endif
 

libc/stdio/lib_fclose.c

@@ -1,7 +1,7 @@
 /****************************************************************************
  * libc/stdio/lib_fclose.c
  *
- *   Copyright (C) 2007-2009, 2011, 3013 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2011, 2013, 2017 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -114,7 +114,8 @@ int fclose(FAR FILE *stream)
 
       /* Release the buffer */
 
-      if (stream->fs_bufstart)
+      if (stream->fs_bufstart != NULL &&
+          (stream->fs_flags & __FS_FLAG_UBF) == 0)
         {
           lib_free(stream->fs_bufstart);
         }

libc/stdio/lib_setvbuf.c

@@ -0,0 +1,270 @@
+/****************************************************************************
+ * libc/stdio/lib_setvbuf.c
+ *
+ *   Copyright (C) 2017 Gregory Nutt. All rights reserved.
+ *   Author: Alan Carvalho de Assis <acassis@gmail.com>
+ *           Gregory Nutt <gnutt@nuttx.org>
+ *
+ * This code is based on Newlib implementation.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT will THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include <nuttx/fs/fs.h>
+
+#include "libc.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: setvbuf
+ *
+ * Description:
+ *   The setvbuf() function may be used after the stream pointed to by
+ *   stream is associated with an open file but before any other operation
+ *   (other than an unsuccessful call to setvbuf()) is performed on the
+ *   stream. The argument type determines how stream will be buffered, as
+ *   follows:
+ *
+ *   _IOFBF - Will cause input/output to be fully buffered.
+ *   _IOLBF - Will cause input/output to be line buffered.
+ *   _IONBF - Will cause input/output to be unbuffered.
+ *
+ * If buf is not a null pointer, the array it points to may be used instead
+ * of a buffer allocated by setvbuf() and the argument size specifies the size
+ * of the array; otherwise, size may determine the size of a buffer allocated
+ * by the setvbuf() function. The contents of the array at any time are
+ * unspecified.
+ *
+ * REVISIT: This initial version of setvbuf has some severe limitations and
+ * not all features features required by the specification are available.
+ * These the limitations are the result of hard-coded stream logic based
+ * the static configuration.  This logic cannot support variable behaviors
+ * without some additional logic.  Specifically, we cannot support:
+ *
+ *  - Any line buffering state that is inconsistent with the configuration
+ *    setting CONFIG_STDIO_LINEBUFFER
+ *  - We cannot support disabling stream buffering if
+ *    CONFIG_STDIO_BUFFER_SIZE > 0
+ *
+ * Parmeters:
+ *  stream - the stream to flush
+ *  buffer - the user allocate buffer. If NULL, will allocates a buffer of
+ *           specified size
+ *  mode   - specifies a mode for file buffering
+ *  size   - size of buffer
+ *
+ * Return:
+ *  Upon successful completion, setvbuf() will return 0. Otherwise, it will
+ *  return a non-zero value if an invalid value is given for type or if the
+ *  request cannot be honored, [CX] and may set errno to indicate the error
+ *
+ ****************************************************************************/
+
+int setvbuf(FAR FILE *stream, FAR char *buffer, int mode, size_t size)
+{
+#if CONFIG_STDIO_BUFFER_SIZE > 0
+  uint8_t flags;
+  int errcode;
+  int ret = OK;
+
+  /* Verify arguments */
+
+  if (mode != _IOFBF && mode != _IOLBF && mode != _IONBF)
+    {
+      errcode = EINVAL;
+      goto errout;
+    }
+
+  /* Make sure that the size argument agrees with the mode */
+
+  if (((mode == _IOFBF || mode == _IOLBF) && size == 0) ||
+      (mode == _IONBF && size > 0))
+    {
+      errcode = EINVAL;
+      goto errout;
+    }
+
+  /* Make sure that the buffer argument agrees with mode */
+
+  if (mode == _IONBF && buffer != NULL)
+    {
+      errcode = EINVAL;
+      goto errout;
+    }
+
+  /* Make sure that the buffer and size argeuments agree */
+
+  if (buffer != NULL && size == 0)
+    {
+      errcode = EINVAL;
+      goto errout;
+    }
+
+  /* Not all features are be available.  Without some additional logic,
+   * we cannot support (1) any line buffering state that is inconsistent
+   * with CONFIG_STDIO_LINEBUFFER nor can we (2) disable buffering if
+   * CONFIG_STDIO_BUFFER_SIZE > 0
+   */
+
+#ifdef CONFIG_STDIO_LINEBUFFER
+  if (mode != _IOLBF)
+#else
+  if (mode != _IOFBF)
+#endif
+    {
+      errcode = ENOSYS;
+      goto errout;
+    }
+
+  /* Make sure that we have exclusive access to the stream */
+
+  lib_take_semaphore(stream);
+
+  /* setvbuf() may only be called AFTER the file has been opened and BEFORE
+   * any operations have been performed on the string.
+   */
+
+  /* Return EBADF if the file is not open */
+
+  if (stream->fs_fd < 0)
+    {
+      errcode = EBADF;
+      goto errout_with_semaphore;
+    }
+
+  /* Return EBUSY if operations have already been performed on the buffer.
+   * Here we really only verify that there is no valid data in the existing
+   * buffer.
+   */
+
+  if (stream->fs_bufpos != stream->fs_bufstart)
+    {
+      errcode = EBUSY;
+      goto errout_with_semaphore;
+    }
+
+  /* Initialize by clearing related flags.  We try to avoid any permanent
+   * changes to the stream structure until we know that we will be
+   * successful.
+   */
+
+  flags = stream->fs_flags & ~__FS_FLAG_UBF;
+
+  /* Allocate a new buffer if one is needed.  We have already verified that:
+   *
+   *   If a buffer is needed, then size > 0
+   *   If a buffer is NOT needed, then buffer is NULL
+   *   If buffer != NULL, then size > 0
+   *
+   * That simplifies the following check:
+   */
+
+#if 0 /* size should always be > 0 in the currently supported configurations */
+  if (size > 0)
+#else
+  DEBUGASSERT(size > 0);
+#endif
+    {
+      FAR unsigned char *newbuf;
+
+      /* A buffer is needed.  Did the caller provide the buffer memory? */
+
+      DEBUGASSERT(mode == _IOFBF || mode == _IOLBF);
+      if (buffer != NULL)
+        {
+          newbuf = (FAR unsigned char *)buffer;
+
+          /* Indicate that we have an I/O buffer managed by the caller of
+           * setvbuf.
+           */
+
+          flags |= __FS_FLAG_UBF;
+        }
+      else
+        {
+          newbuf = (FAR unsigned char *)lib_malloc(size);
+          if (newbuf == NULL)
+            {
+              errcode = ENOMEM;
+              goto errout_with_semaphore;
+            }
+        }
+
+      /* Do not release the previous buffer if it was allocated by the user
+       * on a previous call to setvbuf().
+       */
+
+      if ((stream->fs_flags & __FS_FLAG_UBF) != 0)
+        {
+          lib_free(stream->fs_bufstart);
+        }
+
+      /* Use the new buffer */
+
+      stream->fs_bufstart = newbuf;
+      stream->fs_bufend   = newbuf;
+      stream->fs_bufpos   = newbuf;
+      stream->fs_bufread  = newbuf;
+    }
+
+  /* Update the stream flags and return success */
+
+  stream->fs_flags = flags;
+  lib_give_semaphore(stream);
+  return OK;
+
+errout_with_semaphore:
+  lib_give_semaphore(stream);
+
+errout:
+  set_errno(errcode);
+  return ERROR;
+
+#else
+  /* Return that setvbuf() is not supported */
+
+  set_errno(ENOSYS);
+  return ERROR;
+#endif
+}