rtems/bsps/arm/gdbarmsim/start/syscalls.c

/*
 *  Copied from libgloss 1 Oct 2009.
 *  Minor modifications to work with RTEMS.
 */

/* Support files for GNU libc.  Files in the system namespace go here.
   Files in the C namespace (ie those that do not start with an
   underscore) go in .c.  */

/*
 * Rename all the functions present here to stop then clashing with RTEMS
 * names.
 */

#include <_ansi.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <sys/time.h>
#include <sys/times.h>
#include <errno.h>
#include <reent.h>
#include <unistd.h>
#include <sys/wait.h>
#include <bsp/swi.h>

#include <bsp.h>

/* Forward prototypes.  */
static int	checkerror(int);
static int	error(int);
static int	get_errno(void);

/* Struct used to keep track of the file position, just so we
   can implement fseek(fh,x,SEEK_CUR).  */
struct fdent
{
  int handle;
  int pos;
};

#define MAX_OPEN_FILES 20

/* User file descriptors (fd) are integer indexes into
   the openfiles[] array. Error checking is done by using
   findslot().

   This openfiles array is manipulated directly by only
   these 5 functions:

	findslot() - Translate entry.
	newslot() - Find empty entry.
	initilise_monitor_handles() - Initialize entries.
	_swiopen() - Initialize entry.
	_close() - Handle stdout == stderr case.

   Every other function must use findslot().  */

static struct fdent openfiles [MAX_OPEN_FILES];

static struct fdent* 	findslot (int);
static int		newslot	(void);

/* Register name faking - works in collusion with the linker.  */
register char * stack_ptr __asm__ ("sp");


/* following is copied from libc/stdio/local.h to check std streams */
extern void __sinit(struct _reent *);
#define CHECK_INIT(ptr) \
  do						\
    {						\
      if ((ptr) && !(ptr)->__sdidinit)		\
	__sinit (ptr);				\
    }						\
  while (0)

static int monitor_stdin;
static int monitor_stdout;
static int monitor_stderr;

/* Return a pointer to the structure associated with
   the user file descriptor fd. */
static struct fdent*
findslot (int fd)
{
  CHECK_INIT(_REENT);

  /* User file descriptor is out of range. */
  if ((unsigned int)fd >= MAX_OPEN_FILES)
    return NULL;

  /* User file descriptor is open? */
  if (openfiles[fd].handle == -1)
    return NULL;

  /* Valid. */
  return &openfiles[fd];
}

/* Return the next lowest numbered free file
   structure, or -1 if we can't find one. */
static int
newslot (void)
{
  int i;

  for (i = 0; i < MAX_OPEN_FILES; i++)
    if (openfiles[i].handle == -1)
      break;

  if (i == MAX_OPEN_FILES)
    return -1;

  return i;
}

void
initialise_monitor_handles (void)
{
  int i;

  /* Open the standard file descriptors by opening the special
   * teletype device, ":tt", read-only to obtain a descritpor for
   * standard input and write-only to obtain a descriptor for standard
   * output. Finally, open ":tt" in append mode to obtain a descriptor
   * for standard error. Since this is a write mode, most kernels will
   * probably return the same value as for standard output, but the
   * kernel can differentiate the two using the mode flag and return a
   * different descriptor for standard error.
   */

#ifdef ARM_RDI_MONITOR
  int volatile block[3];

  block[0] = (int) ":tt";
  block[2] = 3;     /* length of filename */
  block[1] = 0;     /* mode "r" */
  monitor_stdin = do_AngelSWI (AngelSWI_Reason_Open, (void *) block);

  block[0] = (int) ":tt";
  block[2] = 3;     /* length of filename */
  block[1] = 4;     /* mode "w" */
  monitor_stdout = do_AngelSWI (AngelSWI_Reason_Open, (void *) block);

  block[0] = (int) ":tt";
  block[2] = 3;     /* length of filename */
  block[1] = 8;     /* mode "a" */
  monitor_stderr = do_AngelSWI (AngelSWI_Reason_Open, (void *) block);
#else
  int fh;
  const char * name;

  name = ":tt";
  __asm__ ("mov r0,%2; mov r1, #0; swi %a1; mov %0, r0"
       : "=r"(fh)
       : "i" (SWI_Open),"r"(name)
       : "r0","r1");
  monitor_stdin = fh;

  name = ":tt";
  __asm__ ("mov r0,%2; mov r1, #4; swi %a1; mov %0, r0"
       : "=r"(fh)
       : "i" (SWI_Open),"r"(name)
       : "r0","r1");
  monitor_stdout = fh;

  name = ":tt";
  __asm__ ("mov r0,%2; mov r1, #8; swi %a1; mov %0, r0"
       : "=r"(fh)
       : "i" (SWI_Open),"r"(name)
       : "r0","r1");
  monitor_stderr = fh;
#endif

  /* If we failed to open stderr, redirect to stdout. */
  if (monitor_stderr == -1)
    monitor_stderr = monitor_stdout;

  for (i = 0; i < MAX_OPEN_FILES; i ++)
    openfiles[i].handle = -1;

  openfiles[0].handle = monitor_stdin;
  openfiles[0].pos = 0;
  openfiles[1].handle = monitor_stdout;
  openfiles[1].pos = 0;
  openfiles[2].handle = monitor_stderr;
  openfiles[2].pos = 0;
}

static int
get_errno (void)
{
#ifdef ARM_RDI_MONITOR
  return do_AngelSWI (AngelSWI_Reason_Errno, NULL);
#else
  register int r0 __asm__ ("r0");
  __asm__ ("swi %a1" : "=r"(r0) : "i" (SWI_GetErrno));
  return r0;
#endif
}

/* Set errno and return result. */
static int
error (int result)
{
  errno = get_errno ();
  return result;
}

/* Check the return and set errno appropriately. */
static int
checkerror (int result)
{
  if (result == -1)
    return error (-1);
  return result;
}

/* fh, is a valid internal file handle.
   ptr, is a null terminated string.
   len, is the length in bytes to read.
   Returns the number of bytes *not* written. */
int
gdbarmsim_swiread (int fh,
                   char * ptr,
                   int len)
{
#ifdef ARM_RDI_MONITOR
  int block[3];

  block[0] = fh;
  block[1] = (int) ptr;
  block[2] = len;

  return checkerror (do_AngelSWI (AngelSWI_Reason_Read, block));
#else
  register int r0 __asm__ ("r0");
  register int r1 __asm__ ("r1");
  register int r2 __asm__ ("r2");
  r0 = fh;
  r1 = (int)ptr;
  r2 = len;
  __asm__ ("swi %a4"
       : "=r" (r0)
       : "0"(r0), "r"(r1), "r"(r2), "i"(SWI_Read));
  return checkerror (r0);
#endif
}

/* fd, is a valid user file handle.
   Translates the return of _swiread into
   bytes read. */
int
gdbarmsim_read (int fd,
                char * ptr,
                int len)
{
  int res;
  struct fdent *pfd;

  pfd = findslot (fd);
  if (pfd == NULL)
    {
      errno = EBADF;
      return -1;
    }

  res = gdbarmsim_swiread (pfd->handle, ptr, len);

  if (res == -1)
    return res;

  pfd->pos += len - res;

  /* res == len is not an error,
     at least if we want feof() to work.  */
  return len - res;
}

/* fd, is a user file descriptor. */
int
gdbarmsim_swilseek (int fd,
                    int ptr,
                    int dir)
{
  int res;
  struct fdent *pfd;

  /* Valid file descriptor? */
  pfd = findslot (fd);
  if (pfd == NULL)
    {
      errno = EBADF;
      return -1;
    }

  /* Valid whence? */
  if ((dir != SEEK_CUR)
      && (dir != SEEK_SET)
      && (dir != SEEK_END))
    {
      errno = EINVAL;
      return -1;
    }

  /* Convert SEEK_CUR to SEEK_SET */
  if (dir == SEEK_CUR)
    {
      ptr = pfd->pos + ptr;
      /* The resulting file offset would be negative. */
      if (ptr < 0)
        {
          errno = EINVAL;
          if ((pfd->pos > 0) && (ptr > 0))
            errno = EOVERFLOW;
          return -1;
        }
      dir = SEEK_SET;
    }

#ifdef ARM_RDI_MONITOR
  int block[2];
  if (dir == SEEK_END)
    {
      block[0] = pfd->handle;
      res = checkerror (do_AngelSWI (AngelSWI_Reason_FLen, block));
      if (res == -1)
        return -1;
      ptr += res;
    }

  /* This code only does absolute seeks.  */
  block[0] = pfd->handle;
  block[1] = ptr;
  res = checkerror (do_AngelSWI (AngelSWI_Reason_Seek, block));
#else
  if (dir == SEEK_END)
    {
      __asm__ ("mov r0, %2; swi %a1; mov %0, r0"
	   : "=r" (res)
	   : "i" (SWI_Flen), "r" (pfd->handle)
	   : "r0");
      checkerror (res);
      if (res == -1)
        return -1;
      ptr += res;
    }

  /* This code only does absolute seeks.  */
  __asm__ ("mov r0, %2; mov r1, %3; swi %a1; mov %0, r0"
       : "=r" (res)
       : "i" (SWI_Seek), "r" (pfd->handle), "r" (ptr)
       : "r0", "r1");
  checkerror (res);
#endif
  /* At this point ptr is the current file position. */
  if (res >= 0)
    {
      pfd->pos = ptr;
      return ptr;
    }
  else
    return -1;
}

int
gdbarmsim_lseek (int fd,
                 int ptr,
                 int dir)
{
  return gdbarmsim_swilseek (fd, ptr, dir);
}

/* write a single character out the hosts stdout */
int
gdbarmsim_writec (const char c)
{
#ifdef ARM_RDI_MONITOR
  int block[1];

  block[0] = ((int) c) & 0xff;;

  return checkerror (do_AngelSWI (AngelSWI_Reason_WriteC, block));
#else
  register int r0 __asm__ ("r0");
  r0 = ((int) c) & 0xff;
  __asm__ ("swi %a2"
       : "=r" (r0)
       : "0"(r0), "i"(SWI_WriteC));
  return checkerror (r0);
#endif
}

/* fh, is a valid internal file handle.
   Returns the number of bytes *not* written. */
int
gdbarmsim_swiwrite (int    fh,
                    char * ptr,
                    int    len)
{
#ifdef ARM_RDI_MONITOR
  int block[3];

  block[0] = fh;
  block[1] = (int) ptr;
  block[2] = len;

  return checkerror (do_AngelSWI (AngelSWI_Reason_Write, block));
#else
  register int r0 __asm__ ("r0");
  register int r1 __asm__ ("r1");
  register int r2 __asm__ ("r2");
  r0 = fh;
  r1 = (int)ptr;
  r2 = len;
  __asm__ ("swi %a4"
       : "=r" (r0)
       : "0"(r0), "r"(r1), "r"(r2), "i"(SWI_Write));
  return checkerror (r0);
#endif
}

/* fd, is a user file descriptor. */
int
gdbarmsim_write (int    fd,
                 char * ptr,
                 int    len)
{
  int res;
  struct fdent *pfd;

  pfd = findslot (fd);
  if (pfd == NULL)
    {
      errno = EBADF;
      return -1;
    }

  res = gdbarmsim_swiwrite (pfd->handle, ptr,len);

  /* Clearly an error. */
  if (res < 0)
    return -1;

  pfd->pos += len - res;

  /* We wrote 0 bytes?
     Retrieve errno just in case. */
  if ((len - res) == 0)
    return error (0);

  return (len - res);
}

int
gdbarmsim_swiopen (const char * path, int flags)
{
  int aflags = 0, fh;
#ifdef ARM_RDI_MONITOR
  int block[3];
#endif

  int fd = newslot ();

  if (fd == -1)
    {
      errno = EMFILE;
      return -1;
    }

  /* It is an error to open a file that already exists. */
  if ((flags & O_CREAT)
      && (flags & O_EXCL))
    {
      struct stat st;
      int res;
      res = gdbarmsim_stat (path, &st);
      if (res != -1)
        {
	  errno = EEXIST;
	  return -1;
        }
    }

  /* The flags are Unix-style, so we need to convert them. */
#ifdef O_BINARY
  if (flags & O_BINARY)
    aflags |= 1;
#endif

  /* In O_RDONLY we expect aflags == 0. */

  if (flags & O_RDWR)
    aflags |= 2;

  if ((flags & O_CREAT)
      || (flags & O_TRUNC)
      || (flags & O_WRONLY))
    aflags |= 4;

  if (flags & O_APPEND)
    {
      /* Can't ask for w AND a; means just 'a'.  */
      aflags &= ~4;
      aflags |= 8;
    }

#ifdef ARM_RDI_MONITOR
  block[0] = (int) path;
  block[2] = strlen (path);
  block[1] = aflags;

  fh = do_AngelSWI (AngelSWI_Reason_Open, block);

#else
  __asm__ ("mov r0,%2; mov r1, %3; swi %a1; mov %0, r0"
       : "=r"(fh)
       : "i" (SWI_Open),"r"(path),"r"(aflags)
       : "r0","r1");
#endif

  /* Return a user file descriptor or an error. */
  if (fh >= 0)
    {
      openfiles[fd].handle = fh;
      openfiles[fd].pos = 0;
      return fd;
    }
  else
    return error (fh);
}

int
gdbarmsim_open (const char * path, int flags, ...)
{
  return gdbarmsim_swiopen (path, flags);
}

/* fh, is a valid internal file handle. */
int
gdbarmsim_swiclose (int fh)
{
#ifdef ARM_RDI_MONITOR
  return checkerror (do_AngelSWI (AngelSWI_Reason_Close, &fh));
#else
  register int r0 __asm__ ("r0");
  r0 = fh;
  __asm__ ("swi %a2"
       : "=r"(r0)
       : "0"(r0), "i" (SWI_Close));
  return checkerror (r0);
#endif
}

/* fd, is a user file descriptor. */
int
gdbarmsim_close (int fd)
{
  int res;
  struct fdent *pfd;

  pfd = findslot (fd);
  if (pfd == NULL)
    {
      errno = EBADF;
      return -1;
    }

  /* Handle stderr == stdout. */
  if ((fd == 1 || fd == 2)
      && (openfiles[1].handle == openfiles[2].handle))
    {
      pfd->handle = -1;
      return 0;
    }

  /* Attempt to close the handle. */
  res = gdbarmsim_swiclose (pfd->handle);

  /* Reclaim handle? */
  if (res == 0)
    pfd->handle = -1;

  return res;
}

int
gdbarmsim_swistat (int fd, struct stat * st)
{
  struct fdent *pfd;
  int res;

  pfd = findslot (fd);
  if (pfd == NULL)
    {
      errno = EBADF;
      return -1;
    }

  /* Always assume a character device,
     with 1024 byte blocks. */
  st->st_mode |= S_IFCHR;
  st->st_blksize = 1024;
#ifdef ARM_RDI_MONITOR
  res = checkerror (do_AngelSWI (AngelSWI_Reason_FLen, &pfd->handle));
#else
  __asm__ ("mov r0, %2; swi %a1; mov %0, r0"
       : "=r" (res)
       : "i" (SWI_Flen), "r" (pfd->handle)
       : "r0");
  checkerror (res);
#endif
  if (res == -1)
    return -1;
  /* Return the file size. */
  st->st_size = res;
  return 0;
}

int
gdbarmsim_fstat (int fd, struct stat * st)
{
  memset (st, 0, sizeof (* st));
  return gdbarmsim_swistat (fd, st);
}

int
gdbarmsim_stat (const char *fname, struct stat *st)
{
  int fd, res;
  memset (st, 0, sizeof (* st));
  /* The best we can do is try to open the file readonly.
     If it exists, then we can guess a few things about it. */
  if ((fd = gdbarmsim_open (fname, O_RDONLY)) == -1)
    return -1;
  st->st_mode |= S_IFREG | S_IREAD;
  res = gdbarmsim_swistat (fd, st);
  /* Not interested in the error. */
  gdbarmsim_close (fd);
  return res;
}

int
gdbarmsim_unlink (const char *path)
{
  int res;
#ifdef ARM_RDI_MONITOR
  int block[2];
  block[0] = (int)path;
  block[1] = strlen(path);
  res = do_AngelSWI (AngelSWI_Reason_Remove, block);
#else
  register int r0 __asm__ ("r0");
  r0 = (int)path;
  __asm__ ("swi %a2"
       : "=r"(r0)
       : "0"(r0), "i" (SWI_Remove));
  res = r0;
#endif
  if (res == -1)
    return error (res);
  return 0;
}

/* Return a clock that ticks at 100Hz.  */
clock_t
gdbarmsim_clock (void)
{
  clock_t timeval;

#ifdef ARM_RDI_MONITOR
  timeval = do_AngelSWI (AngelSWI_Reason_Clock,NULL);
#else
  __asm__ ("swi %a1; mov %0, r0" : "=r" (timeval): "i" (SWI_Clock) : "r0");
#endif
  return timeval;
}

int
gdbarmsim__isatty (int fd)
{
  struct fdent *pfd;

  pfd = findslot (fd);
  if (pfd == NULL)
    {
      errno = EBADF;
      return -1;
    }

#ifdef ARM_RDI_MONITOR
  return checkerror (do_AngelSWI (AngelSWI_Reason_IsTTY, &pfd->handle));
#else
  register int r0 __asm__ ("r0");
  r0 = pfd->handle;
  __asm__ ("swi %a2"
       : "=r" (r0)
       : "0"(r0), "i" (SWI_IsTTY));
  return checkerror (r0);
#endif
}

int
gdbarmsim_system (const char *s)
{
#ifdef ARM_RDI_MONITOR
  int block[2];
  int e;

  /* Hmmm.  The ARM debug interface specification doesn't say whether
     SYS_SYSTEM does the right thing with a null argument, or assign any
     meaning to its return value.  Try to do something reasonable....  */
  if (!s)
    return 1;  /* maybe there is a shell available? we can hope. :-P */
  block[0] = (int)s;
  block[1] = strlen (s);
  e = checkerror (do_AngelSWI (AngelSWI_Reason_System, block));
  if ((e >= 0) && (e < 256))
    {
      /* We have to convert e, an exit status to the encoded status of
         the command.  To avoid hard coding the exit status, we simply
	 loop until we find the right position.  */
      int exit_code;

      for (exit_code = e; e && WEXITSTATUS (e) != exit_code; e <<= 1)
	continue;
    }
  return e;
#else
  register int r0 __asm__ ("r0");
  r0 = (int)s;
  __asm__ ("swi %a2"
       : "=r" (r0)
       : "0"(r0), "i" (SWI_CLI));
  return checkerror (r0);
#endif
}

int
gdbarmsim_rename (const char * oldpath, const char * newpath)
{
#ifdef ARM_RDI_MONITOR
  int block[4];
  block[0] = (int)oldpath;
  block[1] = strlen(oldpath);
  block[2] = (int)newpath;
  block[3] = strlen(newpath);
  return checkerror (do_AngelSWI (AngelSWI_Reason_Rename, block)) ? -1 : 0;
#else
  register int r0 __asm__ ("r0");
  register int r1 __asm__ ("r1");
  r0 = (int)oldpath;
  r1 = (int)newpath;
  __asm__ ("swi %a3"
       : "=r" (r0)
       : "0" (r0), "r" (r1), "i" (SWI_Rename));
  return checkerror (r0);
#endif
}