io_manager.c

busybox最新版的源码:学习和应用的好东东,多的不说了,大家看后再说吧

/* vi: set sw=4 ts=4: */
/*
 * io_manager.c --- the I/O manager abstraction
 */

#include <stdio.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fcntl.h>
#include <time.h>
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#include "ext2_fs.h"
#include "ext2fs.h"

errcode_t io_channel_set_options(io_channel channel, const char *opts)
{
	errcode_t retval = 0;
	char *next, *ptr, *options, *arg;

	EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);

	if (!opts)
		return 0;

	if (!channel->manager->set_option)
		return EXT2_ET_INVALID_ARGUMENT;

	options = malloc(strlen(opts)+1);
	if (!options)
		return EXT2_ET_NO_MEMORY;
	strcpy(options, opts);
	ptr = options;

	while (ptr && *ptr) {
		next = strchr(ptr, '&');
		if (next)
			*next++ = 0;

		arg = strchr(ptr, '=');
		if (arg)
			*arg++ = 0;

		retval = (channel->manager->set_option)(channel, ptr, arg);
		if (retval)
			break;
		ptr = next;
	}
	free(options);
	return retval;
}

errcode_t io_channel_write_byte(io_channel channel, unsigned long offset,
				int count, const void *data)
{
	EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);

	if (channel->manager->write_byte)
		return channel->manager->write_byte(channel, offset,
						    count, data);

	return EXT2_ET_UNIMPLEMENTED;
}