libc/stdio: Allocate file_struct dynamically

1.Reduce the default size of task_group_s(~512B each task)
2.Scale better between simple and complex application

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Change-Id: Ia872137504fddcf64d89c48d6f0593d76d582710

include/limits.h

@@ -138,7 +138,7 @@
 #define _POSIX_OPEN_MAX       CONFIG_NFILE_DESCRIPTORS
 #define _POSIX_PATH_MAX       CONFIG_PATH_MAX
 #define _POSIX_PIPE_BUF       512
-#define _POSIX_STREAM_MAX     CONFIG_NFILE_STREAMS
+#define _POSIX_STREAM_MAX     CONFIG_NFILE_DESCRIPTORS
 #define _POSIX_TZNAME_MAX     3
 
 #ifdef CONFIG_SMALL_MEMORY

include/nuttx/fs/fs.h

@@ -456,33 +456,35 @@ struct filelist
  *                                             buffer+1
  */
 
-#if CONFIG_NFILE_STREAMS > 0
+#ifdef CONFIG_FILE_STREAM
 struct file_struct
 {
-  int                fs_fd;        /* File descriptor associated with stream */
+  FAR struct file_struct *fs_next;      /* Pointer to next file stream */
+  int                     fs_fd;        /* File descriptor associated with stream */
 #ifndef CONFIG_STDIO_DISABLE_BUFFERING
-  sem_t              fs_sem;       /* For thread safety */
-  pid_t              fs_holder;    /* Holder of sem */
-  int                fs_counts;    /* Number of times sem is held */
-  FAR unsigned char *fs_bufstart;  /* Pointer to start of buffer */
-  FAR unsigned char *fs_bufend;    /* Pointer to 1 past end of buffer */
-  FAR unsigned char *fs_bufpos;    /* Current position in buffer */
-  FAR unsigned char *fs_bufread;   /* Pointer to 1 past last buffered read char. */
+  sem_t                   fs_sem;       /* For thread safety */
+  pid_t                   fs_holder;    /* Holder of sem */
+  int                     fs_counts;    /* Number of times sem is held */
+  FAR unsigned char      *fs_bufstart;  /* Pointer to start of buffer */
+  FAR unsigned char      *fs_bufend;    /* Pointer to 1 past end of buffer */
+  FAR unsigned char      *fs_bufpos;    /* Current position in buffer */
+  FAR unsigned char      *fs_bufread;   /* Pointer to 1 past last buffered read char. */
 #endif
-  uint16_t           fs_oflags;    /* Open mode flags */
-  uint8_t            fs_flags;     /* Stream flags */
+  uint16_t                fs_oflags;    /* Open mode flags */
+  uint8_t                 fs_flags;     /* Stream flags */
 #if CONFIG_NUNGET_CHARS > 0
-  uint8_t            fs_nungotten; /* The number of characters buffered for ungetc */
-  unsigned char      fs_ungotten[CONFIG_NUNGET_CHARS];
+  uint8_t                 fs_nungotten; /* The number of characters buffered for ungetc */
+  unsigned char           fs_ungotten[CONFIG_NUNGET_CHARS];
 #endif
 };
 
 struct streamlist
 {
-  sem_t               sl_sem;   /* For thread safety */
-  struct file_struct sl_streams[CONFIG_NFILE_STREAMS];
+  sem_t                   sl_sem;   /* For thread safety */
+  FAR struct file_struct *sl_head;
+  FAR struct file_struct *sl_tail;
 };
-#endif /* CONFIG_NFILE_STREAMS */
+#endif /* CONFIG_FILE_STREAM */
 
 /****************************************************************************
  * Public Function Prototypes
@@ -1029,7 +1031,7 @@ int close_blockdriver(FAR struct inode *inode);
  *
  ****************************************************************************/
 
-#if CONFIG_NFILE_STREAMS > 0
+#ifdef CONFIG_FILE_STREAM
 struct tcb_s; /* Forward reference */
 int fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb,
               FAR struct file_struct **filep);
@@ -1044,7 +1046,7 @@ int fs_fdopen(int fd, int oflags, FAR struct tcb_s *tcb,
  *
  ****************************************************************************/
 
-#if CONFIG_NFILE_STREAMS > 0
+#ifdef CONFIG_FILE_STREAM
 int lib_flushall(FAR struct streamlist *list);
 #endif
 

include/nuttx/lib/lib.h

@@ -2,7 +2,8 @@
  * include/nuttx/lib/lib.h
  * Non-standard, internal APIs available in lib/.
  *
- *   Copyright (C) 2007-2009, 2012-2014, 2016 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2007-2009, 2012-2014, 2016 Gregory Nutt. All rights
+ *   reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -65,18 +66,31 @@ extern "C"
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/
+
 /* Hook for library initialization.  No is needed now, however */
 
 #define lib_initialize()
 
 /* Functions contained in lib_streams.c *************************************/
 
-#if CONFIG_NFILE_STREAMS > 0
+#ifdef CONFIG_FILE_STREAM
 struct task_group_s;
 void lib_stream_initialize(FAR struct task_group_s *group);
 void lib_stream_release(FAR struct task_group_s *group);
 #endif
 
+/* Functions defined in lib_filesem.c ***************************************/
+
+#ifdef CONFIG_STDIO_DISABLE_BUFFERING
+#  define lib_sem_initialize(s)
+#  define lib_take_semaphore(s)
+#  define lib_give_semaphore(s)
+#else
+void lib_sem_initialize(FAR struct file_struct *stream);
+void lib_take_semaphore(FAR struct file_struct *stream);
+void lib_give_semaphore(FAR struct file_struct *stream);
+#endif
+
 /* Functions defined in lib_srand.c *****************************************/
 
 unsigned long nrand(unsigned long limit);

include/nuttx/sched.h

@@ -580,7 +580,7 @@ struct task_group_s
 
   struct filelist tg_filelist;      /* Maps file descriptor to file             */
 
-#if CONFIG_NFILE_STREAMS > 0
+#ifdef CONFIG_FILE_STREAM
   /* FILE streams ***************************************************************/
 
   /* In a flat, single-heap build.  The stream list is allocated with this
@@ -913,9 +913,9 @@ int nxsched_release_tcb(FAR struct tcb_s *tcb, uint8_t ttype);
  */
 
 FAR struct filelist *nxsched_get_files(void);
-#if CONFIG_NFILE_STREAMS > 0
+#ifdef CONFIG_FILE_STREAM
 FAR struct streamlist *nxsched_get_streams(void);
-#endif /* CONFIG_NFILE_STREAMS */
+#endif /* CONFIG_FILE_STREAM */
 
 #ifdef CONFIG_NET
 FAR struct socketlist *nxsched_get_sockets(void);

include/stdio.h

@@ -78,9 +78,9 @@
 
 /* The first three _iob entries are reserved for standard I/O */
 
-#define stdin      (&nxsched_get_streams()->sl_streams[0])
-#define stdout     (&nxsched_get_streams()->sl_streams[1])
-#define stderr     (&nxsched_get_streams()->sl_streams[2])
+#define stdin      (nxsched_get_streams()->sl_head)
+#define stdout     (nxsched_get_streams()->sl_head->fs_next)
+#define stderr     (nxsched_get_streams()->sl_head->fs_next->fs_next)
 
 /* Path to the directory where temporary files can be created */
 

include/sys/syscall_lookup.h

@@ -259,7 +259,7 @@ SYSCALL_LOOKUP(telldir,                    1)
   SYSCALL_LOOKUP(nx_mkfifo,                3)
 #endif
 
-#if CONFIG_NFILE_STREAMS > 0
+#ifdef CONFIG_FILE_STREAM
   SYSCALL_LOOKUP(fs_fdopen,                4)
   SYSCALL_LOOKUP(nxsched_get_streams,      0)
 #endif