show_free.cpp

用linux开发的安防暴警的有关代码

#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include <sys/statvfs.h>
#include <sys/types.h>
#include <mntent.h>
#include <string.h>

#ifndef CHAR_BIT
# define CHAR_BIT 8
#endif

#define ME_DUMMY(fs_name, fs_type) (!strcmp(fs_type, "auto") || !strcmp(fs_type, "ignore"))
#define ME_REMOTE(fs_name, fs_type) (strchr (fs_name, ':') != 0)
#define PROPAGATE_ALL_ONES(x) (signed (x) == -1 ? (uintmax_t)-1 : (uintmax_t)(x))
#define EXTRACT_TOP_BIT(x) ((x) & ((uintmax_t) 1 << (sizeof (x) * CHAR_BIT - 1)))
#define PROPAGATE_TOP_BIT(x) ((x) | ~ (EXTRACT_TOP_BIT (x) - 1))

struct mount_entry
{
	char *me_devname;		// Device node pathname, including "/dev/".
	char *me_mountdir;		// Mount point directory pathname.
	char *me_type;			// "nfs", "4.2", etc.
	dev_t me_dev;			// Device number of me_mountdir.
	unsigned int me_dummy : 1;	// Nonzero for dummy filesystems.
	unsigned int me_remote : 1;	// Nonzero for remote fileystems.
};


struct fs_usage
{
	int fsu_blocksize;		// Size of a block.
	uintmax_t fsu_blocks;		// Total blocks.
	uintmax_t fsu_bfree;		// Free blocks available to superuser.
	uintmax_t fsu_bavail;		// Free blocks available to non-superuser.
	int fsu_bavail_top_bit_set;	// 1 if fsu_bavail represents a value < 0.
	uintmax_t fsu_files;		// Total file nodes.
	uintmax_t fsu_ffree;		// Free file nodes.
};


size_t	show_free(char *,char *);
void read_filesystem_list(char *,char *);
size_t get_free(const char *disk, const char *mount_point,
const char *fstype, int me_dummy, int me_remote);
int get_fs_usage(const char *path, const char *disk, fs_usage *fsp);
static mount_entry	*mount_list;


void read_filesystem_list(char * device,char *mount_point)//device=null,mountdir起作用,mountdir=null,device起作用
{

	mount_list = new mount_entry;
	mount_list->me_devname = device;
	mount_list->me_mountdir = mount_point;
	mount_list->me_type = "nfs";
	mount_list->me_dummy = ME_DUMMY(mount_list->me_devname, mount_list->me_type);
	mount_list->me_remote = ME_REMOTE(mount_list->me_devname, mount_list->me_type);
	mount_list->me_dev = (dev_t)-1;

	return;
}



int get_fs_usage(const char *path, const char *disk, fs_usage *fsp)
{
	struct statvfs fsd;

	if (statvfs (path, &fsd) < 0)
		return -1;

	fsp->fsu_blocksize =PROPAGATE_ALL_ONES (fsd.f_frsize ? fsd.f_frsize : fsd.f_bsize);
	fsp->fsu_blocks = PROPAGATE_ALL_ONES (fsd.f_blocks);
	fsp->fsu_bfree = PROPAGATE_ALL_ONES (fsd.f_bfree);
	fsp->fsu_bavail = PROPAGATE_TOP_BIT (fsd.f_bavail);
	fsp->fsu_bavail_top_bit_set = EXTRACT_TOP_BIT (fsd.f_bavail) != 0;
	fsp->fsu_files = PROPAGATE_ALL_ONES (fsd.f_files);
	fsp->fsu_ffree = PROPAGATE_ALL_ONES (fsd.f_ffree);

	return 0;
}



size_t get_free(const char *disk, const char *mount_point,const char *fstype, int me_dummy, int me_remote)

{
	struct fs_usage fsu;
	const char *stat_file;

	stat_file = mount_point ? mount_point : disk;

	if(get_fs_usage(stat_file, disk, &fsu))
		return 0;

	size_t free = fsu.fsu_bavail * fsu.fsu_blocksize;

	return free;
}






size_t show_free(char * device,char *mount_point)
{
	read_filesystem_list(device,mount_point);
	if(mount_list == NULL)
		return 0;

	mount_entry *me = mount_list;

	size_t df = (size_t)get_free(me->me_devname, me->me_mountdir,
		me->me_type, me->me_dummy, me->me_remote);

	delete	mount_list;
	return df;
}