/*
 * Copyright (c) 2000-2002, 2004, 2005 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 */

#include "sm/generic.h"
SM_RCSID("@(#)$Id: stdio.c,v 1.33 2006/07/16 02:07:40 ca Exp $")
#include "sm/error.h"
#include "fcntl.h"
#include "sm/memops.h"
#include "sm/stat.h"
#include "sm/time.h"
#include "sm/heap.h"
#include "sm/assert.h"
#include "sm/varargs.h"
#include "sm/io.h"
#include "sm/fdset.h"
#include "io-int.h"

/*
**  Overall:
**  Small standard I/O/seek/close functions.
**  These maintain the `known seek offset' for seek optimization.
*/

/*
**  SM_STDOPEN -- open a file with stdio behavior
**
**  Not associated with the system's stdio in libc.
**
**	Parameters:
**		fp -- file pointer to be associated with the open
**		info -- pathname of the file to be opened
**		flags -- indicates type of access methods
**
**	Returns:
**		Failure: error code
**		Success: 0 or greater (fd of file from open(2)).
**
*/

/* ARGSUSED3 */
sm_ret_T
sm_stdopen(sm_file_T *fp, const void *info, int flags, va_list ap)
{
	const char *path = (const char *) info;
	int oflags;

	switch (flags)
	{
	  case SM_IO_RDWR:
		oflags = O_RDWR;
		break;
	  case SM_IO_RDWRCR:
		oflags = O_RDWR | O_CREAT;
		break;
	  case SM_IO_RDWRTR:
		oflags = O_RDWR | O_CREAT | O_TRUNC;
		break;
	  case SM_IO_RDONLY:
		oflags = O_RDONLY;
		break;
	  case SM_IO_WRONLY:
		oflags = O_WRONLY | O_CREAT | O_TRUNC;
		break;
	  case SM_IO_APPEND:
		oflags = O_APPEND | O_WRONLY | O_CREAT;
		break;
	  case SM_IO_APPENDRW:
		oflags = O_APPEND | O_RDWR | O_CREAT;
		break;
	  default:
		return sm_error_perm(SM_EM_IO, EINVAL);
	}
	f_fd(*fp) = open(path, oflags | O_NONBLOCK,
			  S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
	if (f_fd(*fp) < 0)
		return sm_error_perm(SM_EM_IO, errno);

	if (oflags & O_APPEND)
		(void) f_seek(*fp)(fp, (off_t) 0, SEEK_END);

	return f_fd(*fp);
}

/*
**  SM_STDREAD -- read from the file
**
**	Parameters:
**		fp -- file pointer to read from
**		buf -- location to place read data
**		n -- number of bytes to read
**		bytesread -- number of bytes read (output)
**
**	Returns:
**		usual sm_error code
**
**	Side Effects:
**		Updates internal offset into file.
*/

sm_ret_T
sm_stdread(sm_file_T *fp, uchar *buf, size_t n, ssize_t *bytesread)
{
	ssize_t ret;
	sm_ret_T res;

	/* should we decrease the timeout in the loop? */
	*bytesread = 0;
	do
	{
		if (fp->f_timeout > 0)
		{
			res = sm_read_wait(f_fd(*fp), fp->f_timeout);
			if (sm_is_err(res))
				return res;
		}
		errno = 0;
		ret = read(f_fd(*fp), buf, n);
	} while (ret == -1 && errno == EINTR);
	if (ret == -1)
		return sm_error_perm(SM_EM_IO, errno);
	*bytesread = ret;

	/* if the read succeeded, update the current offset */
	if (ret > 0)
		fp->f_lseekoff += ret;
	return SM_SUCCESS;
}

/*
**  SM_STDWRITE -- write to the file
**
**	Parameters:
**		fp -- file pointer ro write to
**		buf -- location of data to be written
**		n -- number of bytes to write
**		byteswritten -- number of bytes written (output)
**
**	Returns:
**		usual sm_error code
*/

sm_ret_T
sm_stdwrite(sm_file_T *fp, const uchar *buf, size_t n, ssize_t *byteswritten)
{
	ssize_t ret;
	sm_ret_T res;

	/* should we decrease the timeout in the loop? */
	*byteswritten = 0;
	do
	{
		if (fp->f_timeout > 0)
		{
			res = sm_write_wait(f_fd(*fp), fp->f_timeout);
			if (sm_is_err(res))
				return res;
		}
		errno = 0;
		ret = write(f_fd(*fp), buf, n);
	} while (ret == -1 && errno == EINTR);
	if (ret == -1)
		return sm_error_perm(SM_EM_IO, errno);
	*byteswritten = ret;
	return SM_SUCCESS;
}

/*
**  SM_STDSEEK -- set the file offset position
**
**	Parmeters:
**		fp -- file pointer to position
**		offset -- how far to position from "base" (set by 'whence')
**		whence -- indicates where the "base" of the 'offset' to start
**
**	Results:
**		Failure: -1 and sets errno
**		Success: the current offset
**
**	Side Effects:
**		Updates the internal value of the offset.
*/

sm_ret_T
sm_stdseek(sm_file_T *fp, off_t offset, int whence)
{
	off_t ret;

	ret = lseek(f_fd(*fp), (off_t) offset, whence);
	if (ret == (off_t) -1)
		return sm_error_perm(SM_EM_IO, errno);
	fp->f_lseekoff = ret;
	return SM_SUCCESS;
}

/*
**  SM_STDCLOSE -- close the file
**
**	Parameters:
**		fp -- the file pointer to close
**		flags -- ignored
**
**	Returns:
**		usual sm_error code.
*/

sm_ret_T
sm_stdclose(sm_file_T *fp, int flags)
{
	if (close(f_fd(*fp)) == -1)
		return sm_error_perm(SM_EM_IO, errno);
	return SM_SUCCESS;
}

/*
**  SM_STDSETMODE -- set the access mode for the file
**	Called by sm_stdsetinfo().
**	Do we really want to allow changing the mode??
**
**	Parameters:
**		fp -- file pointer
**		mode -- new mode to set the file access to
**
**	Results:
**		usual sm_error code.
*/

static sm_ret_T
sm_stdsetmode(sm_file_T *fp, const int *mode)
{
	int flags = 0;

	switch (*mode)
	{
	  case SM_IO_RDWR:
		flags |= SMRW;
		break;
	  case SM_IO_RDONLY:
		flags |= SMRD;
		break;
	  case SM_IO_WRONLY:
		flags |= SMWR;
		break;
	  case SM_IO_APPEND:
	  default:
		return sm_error_perm(SM_EM_IO, EINVAL);
	}
	f_flags(*fp) = f_flags(*fp) & ~SMMODEMASK;
	f_flags(*fp) |= flags;
	return SM_SUCCESS;
}

/*
**  SM_STDGETMODE -- for getinfo determine open mode
**
**  Called by sm_stdgetinfo().
**
**	Parameters:
**		fp -- the file mode being determined
**		mode -- internal mode to map to external value
**
**	Results:
**		Success: external mode value
**		Failure: usual sm_error code.
*/

static sm_ret_T
sm_stdgetmode(sm_file_T *fp, int *mode)
{
	switch (f_flags(*fp) & SMMODEMASK)
	{
	  case SMRW:
		*mode = SM_IO_RDWR;
		break;
	  case SMRD:
		*mode = SM_IO_RDONLY;
		break;
	  case SMWR:
		*mode = SM_IO_WRONLY;
		break;
	  default:
		return sm_error_perm(SM_EM_IO, EINVAL);
	}
	return SM_SUCCESS;
}

/*
**  SM_STDSETINFO -- set/modify information for a file
**
**	Parameters:
**		fp -- file to set info for
**		what -- type of info to set
**		valp -- location of data used for setting
**
**	Returns:
**		usual sm_error code.
*/

sm_ret_T
sm_stdsetinfo(sm_file_T *fp, int what, void *valp)
{
	switch (what)
	{
	  case SM_IO_WHAT_MODE:
		return sm_stdsetmode(fp, (const int *)valp);

	  default:
		return sm_error_perm(SM_EM_IO, EINVAL);
	}
}

/*
**  SM_STDGETINFO -- get information about the open file
**
**	Parameters:
**		fp -- file to get info for
**		what -- type of info to get
**		valp -- location to place found info
**
**	Returns:
**		Success: may or may not place info in 'valp' depending
**			on 'what' value, and returns values >=0. Return
**			value may be the obtained info
**		Failure: usual sm_error code.
*/

sm_ret_T
sm_stdgetinfo(sm_file_T *fp, int what, void *valp)
{
	switch (what)
	{
	  case SM_IO_WHAT_MODE:
		return sm_stdgetmode(fp, (int *)valp);

	  case SM_IO_WHAT_FD:
		return f_fd(*fp);

	  case SM_IO_WHAT_SIZE:
	  {
		struct stat st;

		if (fstat(f_fd(*fp), &st) < 0)
			return sm_error_perm(SM_EM_IO, errno);
		return st.st_size;
	  }

	  case SM_IO_IS_READABLE:
		{
			fd_set readfds;
			struct timeval timeout;

			FD_ZERO(&readfds);
			SM_FD_SET(f_fd(*fp), &readfds);
			timeout.tv_sec = 0;
			timeout.tv_usec = 0;
			if (select(f_fd(*fp) + 1,
				   FDSET_CAST &readfds,
				   NULL,
				   NULL,
				   &timeout) > 0 &&
			    SM_FD_ISSET(f_fd(*fp), &readfds))
				return 1;
			return 0;
		}

	  default:
		return sm_error_perm(SM_EM_IO, EINVAL);
	}
}

/*
**  SM_STDFDOPEN -- open file by primitive 'fd' rather than pathname
**
**	I/O function to handle fdopen() stdio equivalence. The rest of
**	the functions are the same as the sm_stdopen() above.
**
**	Parameters:
**		fp -- the file pointer to be associated with the open
**		name -- the primitive file descriptor for association
**		flags -- indicates type of access methods
**
**	Results:
**		usual sm_error code.
*/

/* ARGSUSED3 */
sm_ret_T
sm_stdfdopen(sm_file_T *fp, const void *info, int flags, va_list ap)
{
	int oflags, tmp, fdflags, fd;

	fd = *((int *) info);
	switch (flags)
	{
	  case SM_IO_RDWR:
		oflags = O_RDWR | O_CREAT;
		break;
	  case SM_IO_RDONLY:
		oflags = O_RDONLY;
		break;
	  case SM_IO_WRONLY:
		oflags = O_WRONLY | O_CREAT | O_TRUNC;
		break;
	  case SM_IO_APPEND:
		oflags = O_APPEND | O_WRONLY | O_CREAT;
		break;
	  case SM_IO_APPENDRW:
		oflags = O_APPEND | O_RDWR | O_CREAT;
		break;
	  default:
		return sm_error_perm(SM_EM_IO, EINVAL);
	}

	/* Make sure the mode the user wants is a subset of the actual mode. */
	errno = 0;
	fdflags = fcntl(fd, F_GETFL, 0);
	if (fdflags < 0)
		return sm_error_perm(SM_EM_IO, errno);

	tmp = fdflags & O_ACCMODE;
	if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE)))
		return sm_error_perm(SM_EM_IO, EINVAL);
	f_fd(*fp) = fd;
	if (oflags & O_APPEND)
		(void) (*fp->f_stream.fs_seek)(fp, (off_t)0, SEEK_END);
	return SM_SUCCESS;
}

/*
**  SM_IO_FOPEN -- open a file
**
**	Same interface and semantics as the open() system call,
**	except that it returns sm_file_T* instead of a file descriptor.
**
**	Parameters:
**		pathname -- path of file to open
**		flags -- flags controlling the open
**		...  -- option "mode" for opening the file
**
**	Returns:
**		Returns NULL and sets errno if open() fails.
**		Returns an sm_file_T pointer on success.
*/

sm_ret_T
sm_io_fopen(char *pathname, int flags, sm_file_T **newfp, ...)
{
	mode_t mode;
	sm_file_T *fp;
	int ioflags;
	sm_ret_T res;

	if (flags & O_CREAT)
	{
		va_list ap;

		va_start(ap, newfp);
		mode = (mode_t) va_arg(ap, int);
		va_end(ap);
	}
	else
		mode = 0;

	switch (flags & O_ACCMODE)
	{
	  case O_RDONLY:
		ioflags = SMRD;
		break;
	  case O_WRONLY:
		ioflags = SMWR;
		break;
	  case O_RDWR:
		ioflags = SMRW;
		break;
	  default:
		sm_abort("sm_io_fopen: bad flags 0%o", flags);
	}

	res = sm_fp(SmStStdio, ioflags, NULL, &fp);
	if (sm_is_err(res))
		return res;
	errno = 0;
	f_fd(*fp) = open(pathname, flags, mode);
	if (f_fd(*fp) == -1)
	{
		f_flags(*fp) = 0;
		fp->sm_magic = SM_MAGIC_NULL;
		return sm_error_perm(SM_EM_IO, errno);
	}
	*newfp = fp;
	return SM_SUCCESS;
}