stdio.c

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	while (bytes) {
		if ((rv = write(fp->fd, p, bytes)) < 0) {
			rv = 0;
			if (errno != EINTR) {
				break;
			}
		}
		p += rv;
		bytes -= rv;
	}
	if (bytes) {
		fp->mode |= __MODE_ERR;
	}

 DONE:
	return (p - (unsigned char *)buf);
}
#endif

#ifdef L_rewind
void rewind(fp)
FILE *fp;
{
	clearerr(fp);				/* Clear errors first, then seek in case */
	fseek(fp, 0, SEEK_SET);		/* there is an error seeking. */
}
#endif

#ifdef L_fseek
int fseek(FILE *fp, long int offset, int ref)
{
#if SEEK_SET != 0 || SEEK_CUR != 1 || SEEK_END != 2
#error Assumption violated -- values of SEEK_SET, SEEK_CUR, SEEK_END
#endif

	if ((ref < 0) || (ref > 2)) {
		__set_errno(EINVAL);
		return -1;
	}

	if (WRITING(fp)) {
		fflush(fp);				/* We'll deal with errors below. */
		/* After fflush, bufpos is at CUR. */
	} else if (READING(fp)) {
		if (ref == SEEK_CUR) {
			/* Correct offset to take into account position in buffer. */
			offset -= (fp->bufread - fp->bufpos);
			if (fp->mode & __MODE_UNGOT) { /* If we had an ungetc'd char, */
				--offset;			/* adjust offset (clear flag below). */
			}
		}
	}

	if ((fp->mode & __MODE_ERR) || 
		(((ref != SEEK_CUR) || offset) && (lseek(fp->fd, offset, ref) < 0))) {
		return -1;
	}

	if (READING(fp)) {
		fp->bufpos = fp->bufread = fp->bufstart;
	}
	fp->mode &=	~(__MODE_EOF | __MODE_UNGOT);

	return 0;
}
#endif

#ifdef L_ftell
long ftell(fp)
FILE *fp;
{
	/* Note: can't do fflush here since it would discard any ungetc's. */
	off_t pos;

    pos = lseek(fp->fd, 0, SEEK_CUR); /* Get kernels idea of position. */
	if (pos < 0) {
		return -1;
	}

	if (WRITING(fp)) {
		pos += (fp->bufpos - fp->bufstart);	/* Adjust for buffer position. */
	} else if (READING(fp)) {
	    pos -= (fp->bufread - fp->bufpos);	/* Adjust for buffer position. */
		if (fp->mode & __MODE_UNGOT) {
			--pos;
		}
		if (pos < 0) {			/* ungetcs at start of file? */
			__set_errno(EIO);
			pos = -1;
		}
	}

	return pos;
}
#endif

#ifdef L__fopen
/*
 * This Fopen is all three of fopen, fdopen and freopen. The macros in
 * stdio.h show the other names.
 */
static __inline FILE *_alloc_stdio_stream(void)
{
	FILE *fp;

	if (_free_file_list) {
		fp = _free_file_list;
		_free_file_list = fp->next;
	} else if (!(fp = malloc(sizeof(FILE)))) {
		return 0;
	}
	fp->mode = __MODE_FREEFIL | _IOFBF;
	/* Initially set to use builtin buffer of FILE structure. */
	fp->bufstart = fp->unbuf;
	fp->bufend = fp->unbuf + sizeof(fp->unbuf);
	return fp;
}

FILE *__fopen(fname, fd, fp, mode)
const char *fname;
int fd;
FILE *fp;
const char *mode;
{
	FILE *nfp;
	unsigned char *p;
	int open_mode;
	int cur_mode;

	nfp = fp;

	/* Parse the mode string arg. */
	switch (*mode++) {
		case 'r':				/* read */
			open_mode = O_RDONLY;
			break;
		case 'w':				/* write (create or truncate)*/
			open_mode = (O_WRONLY | O_CREAT | O_TRUNC);
			break;
		case 'a':				/* write (create or append) */
			open_mode = (O_WRONLY | O_CREAT | O_APPEND);
			break;
		default:				/* illegal mode */
			__set_errno(EINVAL);
			goto _fopen_ERROR;
	}

	if ((*mode == 'b')) {		/* binary mode (nop for uClibc) */
		++mode;
	}


#if O_RDONLY != 0 || O_WRONLY != 1 || O_RDWR != 2
#error Assumption violated concerning open mode constants!
#endif

	if (*mode == '+') {			/* read-write */
		++mode;
		open_mode &= ~(O_RDONLY | O_WRONLY);
		open_mode |= O_RDWR;
	}

	while (*mode) {				/* ignore everything else except ... */
		if (*mode == 'x') {		/* open exclusive -- GNU extension */
			open_mode |= O_EXCL;
		}
		++mode;
	}

	if (fp == 0) {				/* We need a FILE so allocate it before */
		if (!(nfp = _alloc_stdio_stream())) {
			return 0;
		}
	}

	if (fname) {				/* Open the file itself */
		fd = open(fname, open_mode, 0666);
	} else {					/* fdopen -- check mode is compatible. */
#if O_ACCMODE != 3 || O_RDONLY != 0 || O_WRONLY != 1 || O_RDWR != 2
#error Assumption violated - mode constants
#endif
		cur_mode = fcntl(fd, F_GETFL);
		if (cur_mode == -1) {
			fd = -1;
		} else if (!(cur_mode & O_RDWR) 
				   && ((cur_mode ^ open_mode) & O_ACCMODE)) {
			__set_errno(EINVAL);
			fd = -1;
		}
	}

	if (fd < 0) {				/* Error from open or bad arg passed. */
	_fopen_ERROR:
		if (nfp) {
			_free_stdio_stream(nfp);
		}
		return 0;
	}

	nfp->fd = fd;				/* Set FILE's fd before adding to open list. */

	if (fp == 0) {				/* Not freopen so... */
		nfp->next = __IO_list;	/* use newly created FILE and */
		__IO_list = nfp;		/* add it to the list of open files. */

		if ((p = _alloc_stdio_buffer(BUFSIZ)) != 0) {
			nfp->bufstart = p;
			nfp->bufend = p + BUFSIZ;
			nfp->mode |= __MODE_FREEBUF;
		}
	}

	/* Ok, file's ready clear the buffer and save important bits */
	nfp->bufpos = nfp->bufstart;
	nfp->mode |= isatty(fd);
	nfp->bufread = nfp->bufwrite = 0;
	if (!(open_mode & O_WRONLY)) {
		nfp->bufread = nfp->bufstart;
	}
	if (open_mode & (O_WRONLY | O_RDWR)) {
		nfp->bufwrite = nfp->bufstart;
	}

	return nfp;
}
#endif

#ifdef L_fclose
int fclose(fp)
FILE *fp;
{
	FILE *prev;
	FILE *ptr;
	int rv;

	rv = 0;
	if (WRITING(fp)) {			/* If there are buffered chars to write... */
		rv = fflush(fp);		/* write them. */
	}
	if (close(fp->fd)) {		/* Need to close even if fflush fails. */
		rv = EOF;
	}

	prev = 0;					/* Remove file from open list. */
	for (ptr = __IO_list; ptr ; ptr = ptr->next) {
		if (ptr == fp) {
			if (prev == 0) {
				__IO_list = fp->next;
			} else {
				prev->next = fp->next;
			}
			break;
		}
		prev = ptr;
	}

	_free_stdio_stream(fp);		/* Finally free the stream if necessary. */

	return rv;
}
#endif

#ifdef L__free_stdio_stream
/* The following is only called by fclose and _fopen. */
void _free_stdio_stream(FILE *fp)
{
	_free_stdio_buffer_of_file(fp);	/* Free buffer if necessary. */

	if (!(fp->mode & __MODE_FREEFIL)) {
		return;
	}

	/* Note: we generally won't bother checking for bad pointers here. */
	if ((fp >= _stdio_streams) && (fp < _stdio_streams + FIXED_STREAMS)) {
		assert( (fp - _stdio_streams) % ((_stdio_streams+1) -_stdio_streams)
				== 0 );
		fp->next = _free_file_list;
		_free_file_list = fp;
		return;
	}
	free(fp);
}
#endif

#ifdef L_setbuffer
void setbuffer(FILE *fp, char *buf, size_t size)
{
	int mode;

	mode = _IOFBF;
	if (!buf) {
		mode = _IONBF;
	}
	setvbuf(fp, buf, mode, size);
}
#endif

#ifdef L_setvbuf
int setvbuf(FILE *fp, char *buf, int mode, size_t size)
{
	int allocated_buf_flag;

	if ((mode < 0) || (mode > 2)) {	/* Illegal mode. */
		return EOF;
	}

#if FLEXIBLE_SETVBUF
	/* C89 standard requires no ops before setvbuf, but we can be flexible. */
	/* NOTE: This will trash any chars ungetc'd!!! */
	if (fseek(fp, 0, SEEK_CUR)) {
		return EOF;
	}
#endif

	/* Note: If size == 2 we could use FILE's builting buffer as well, but */
	/* I don't think the benefit is worth the code size increase. */
	if ((mode == _IONBF) || (size < 1)) {
		size = 1;				/* size == 1 _REQUIRED_ for _IONBF!!! */
		buf = fp->unbuf;
	}

	fp->mode &= ~(__MODE_BUF);	/* Clear current mode */
	fp->mode |= mode;			/*   and set new one. */

	allocated_buf_flag = 0;
	if ((!buf) && (size != (fp->bufend - fp->bufstart))) {
		/* No buffer supplied and requested size different from current. */
		allocated_buf_flag = __MODE_FREEBUF;
		if (!(buf = _alloc_stdio_buffer(size))) {
			return EOF;			/* Keep current buffer. */
		}
	}

	if (buf && (buf != (char *) fp->bufstart)) { /* Want different buffer. */
		_free_stdio_buffer_of_file(fp);	/* Free the old buffer. */
		fp->mode |= allocated_buf_flag;	/* Allocated? or FILE's builtin. */
		fp->bufstart = buf;
		fp->bufend = buf + size;
		fp->bufpos = fp->bufstart;
		if (READABLE(fp)) {
			fp->bufread = fp->bufstart;
		}
		if (WRITEABLE(fp)) {
			fp->bufwrite = fp->bufstart;
		}
	}

	return 0;
}
#endif

#ifdef L_setbuf
void setbuf(FILE *fp, char *buf)
{
	int mode;

	mode = _IOFBF;
	if (!buf) {
		mode = _IONBF;
	}
	setvbuf(fp, buf, mode, BUFSIZ);
}
#endif

#ifdef L_setlinebuf
void setlinebuf(FILE *fp)
{
	setvbuf(fp, NULL, _IOLBF, BUFSIZ);
}
#endif

#ifdef L_ungetc
/* 
 * NOTE: Only one character of pushback is guaranteed, although sometimes
 * it is possible to do more.  You have 1 plus as many characters of pushback
 * as have been read since that last buffer-fill.
 */
int ungetc(c, fp)
int c;
FILE *fp;
{
	unsigned char *p;

	/* If can't read or there's been an error, or c == EOF, or ungot slot
	 * already filled, then return EOF */
		/*
		 * This can only happen if an fgetc triggered a read (that filled
		 * the buffer for case 2 above) and then we ungetc 3 chars.
		 */
	if (!READABLE(fp) || (fp->mode & (__MODE_UNGOT | __MODE_ERR))
		|| (c == EOF) ) {
		return EOF;
	}

	if (WRITING(fp)) {			/* Commit any write-buffered chars. */
		fflush(fp);
	}

	if (fp->bufpos > fp->bufstart) { /* We have space before bufpos. */
		p = --fp->bufpos;
	} else if (fp->bufread == fp->bufpos) { /* Buffer is empty. */
		p = fp->bufread++;
	} else {
		fp->mode |= __MODE_UNGOT;
		p = &(fp->ungot);
	}
	fp->mode &= ~(__MODE_EOF);	/* Clear EOF indicator. */

	if (*p != (unsigned char) c) { /* Don't store if same, because could */
		*p = (unsigned char) c;	/* be sscanf from a const string!!! */
	}

	return c;
}
#endif

#ifdef L_fopen
#undef fopen
FILE *fopen(const char *__restrict filename,
			const char *__restrict mode)
{
	return __fopen(filename, -1, NULL, mode);
}
#endif

#ifdef L_freopen
FILE *freopen(__const char *__restrict filename,
			  __const char *__restrict mode, FILE *__restrict fp)
{
	/* fflush file, close the old fd, and reset modes. */
	if (WRITING(fp)) {			/* If anything in the write buffer... */
		fflush(fp);				/* write it. */
	}
	close(fp->fd);				/* Close the file. */
	fp->mode &= (__MODE_FREEFIL | __MODE_FREEBUF); /* Reset the FILE modes. */
	fp->mode |= _IOFBF;

	return __fopen(filename, -1, fp, mode);
}
#endif

#ifdef L_fsfopen
FILE *fsfopen(__const char *__restrict filename,
			  __const char *__restrict mode, FILE *__restrict fp)
{
	fp->mode = _IOFBF;
	fp->bufstart = fp->unbuf;
	fp->bufend = fp->unbuf + sizeof(fp->unbuf);

	return __fopen(filename, -1, fp, mode);
}
#endif

#ifdef L_fdopen
#undef fdopen
FILE *fdopen(int fd, __const char *mode)
{
	return __fopen(NULL, fd, NULL, mode);
}
#endif

#ifdef L_getchar
#undef getchar
int getchar(void)
{
	return getc(stdin);
}
#endif

#ifdef L_putchar
#undef putchar
int putchar(int c)
{
	return putc(c, stdout);
}
#endif

#ifdef L_clearerr
#undef clearerr
void clearerr(FILE *fp)
{
	fp->mode &= ~(__MODE_EOF | __MODE_ERR);
}
#endif

#ifdef L_feof
#undef feof
int feof(FILE *fp)
{
  	return fp->mode & __MODE_EOF;
}
#endif

#ifdef L_ferror
#undef ferror
int ferror(FILE *fp)
{
	return fp->mode & __MODE_ERR;
}
#endif

#ifdef L_fileno
int fileno(FILE *fp)
{
	return fp->fd;
}
#endif

#ifdef L_fgetpos
int fgetpos(FILE *fp, fpos_t *pos)
{
	fpos_t p;

	if (!pos) {					/* NULL pointer. */
		__set_errno(EINVAL);
		return -1;
	}

	if ((p = ftell(fp)) < 0) {	/* ftell failed. */
		return -1;				/* errno set by ftell. */
	}

	*pos = p;
	return 0;
}
#endif

#ifdef L_fsetpos
int fsetpos(FILE *fp, __const fpos_t *pos)
{
	if (pos) {					/* Pointer ok. */
		return fseek(fp, *pos, SEEK_SET);
	}
	__set_errno(EINVAL);				/* NULL pointer. */
	return EOF;
}
#endif