Linux Advance--目录下文件类型统计

#include <dirent.h>

DIR *opendir(const char *pathname);

struct dirent *readdir(DIR *dp);

void rewinddir(DIR *dp);

int closedir(DIR *dp);

long telldir(DIR *dp);

void seekdir(DIR *dp, long loc);

struct dirent {
ino_t	d_ino;					/* i-node number */
char	d_name[NAME_MAX + 1];	/* null-terminated filename */
};

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <limits.h>
#include <sys/stat.h>

typedef int Myfunc(const char *, const struct stat *, int);

static Myfunc	myfunc;
static int		myftw(char *, Myfunc *);
static int		dopath(Myfunc *);
char *			path_alloc(int *);

static long nreg, ndir, nblk, nchr, nfifo, nslink, nsock, ntot;

int main(int argc, char *argv[])
{
int 	ret;

if (argc != 2) {
printf("usage: ftw <starting-pathname>\n");
exit(1);
}

ret = myftw(argv[1], myfunc);

ntot = nreg + ndir + nblk + nchr + nfifo + nslink + nsock;
if (ntot == 0)
ntot = 1;
printf("regular files  = %7ld, %5.2f %%\n", nreg, nreg*100.0/ntot);
printf("directories    = %7ld, %5.2f %%\n", ndir, ndir*100.0/ntot);
printf("block special  = %7ld, %5.2f %%\n", nblk, nblk*100.0/ntot);
printf("char special   = %7ld, %5.2f %%\n", nchr, nchr*100.0/ntot);
printf("FIFOs          = %7ld, %5.2f %%\n", nfifo, nfifo*100.0/ntot);
printf("symbolic links = %7ld, %5.2f %%\n", nslink, nslink*100.0/ntot);
printf("sockets        = %7ld, %5.2f %%\n", nsock, nsock*100.0/ntot);

exit(ret);
}

/*
* Descend through the hierarchy, starting at "pathname".
* The caller's func() is called for every file.
*/
#define FTW_F	1		/* file other than directory */
#define FTW_D	2		/* directory */
#define FTW_DNR 3		/* directory that can't be read */
#define FTW_NS  4		/* file that we can't stat */

static char *fullpath;		/* contains full pathname for every file */
static int myftw(char *pathname, Myfunc *func)
{
int len;
fullpath = path_alloc(&len);	/* malloc's for PATH_MAX+1 bytes */

strncpy(fullpath, pathname, len);
fullpath[len-1] = 0;

return (dopath(func));
}

/*
* Descend through the hierarchy, starting at "fullpath".
* If "fullpath" is anything other than a directory, we lstat() it,
* call func(), and return. For a directory, we call ourself
* recursively for each name in the directory.
*/
static int dopath(Myfunc *func)
{
struct stat		statbuf;
struct dirent	*dirp;
DIR				*dp;
int				ret;
char			*ptr;

if (lstat(fullpath, &statbuf) < 0)	/* stat error */
return func(fullpath, &statbuf, FTW_NS);
if (S_ISDIR(statbuf.st_mode) == 0)	/* not a directory */
return func(fullpath, &statbuf, FTW_F);

/*
* It's a directory. First call func() for the directory,
* then process each filename in the directory.
*/
if (ret = func(fullpath, &statbuf, FTW_D) != 0)
return ret;

ptr = fullpath + strlen(fullpath);	/* point to end of fullpath */
*ptr++ = '/';
*ptr = 0;

if ((dp = opendir(fullpath)) == 0)	/* can't read directory */
return func(fullpath, &statbuf, FTW_DNR);

while ((dirp = readdir(dp)) != 0) {
if (strcmp(dirp->d_name, ".") == 0 ||
strcmp(dirp->d_name, "..") == 0)
continue;		/* ignore dot and dot-dot */

strcpy(ptr, dirp->d_name);	/* append name after slash */

if ((ret = dopath(func)) != 0)		/* recursive */
break;	/* time to leave */
}
ptr[-1] = 0;	/* erase everything from slash onwards */

if (closedir(dp) < 0) {
printf("can't close directory %s\n", fullpath);
exit(1);
}

return ret;
}

static int myfunc(const char *pathname, const struct stat *statptr, int type)
{
switch (type) {
case FTW_F:
switch (statptr->st_mode & S_IFMT) {
case S_IFREG:	nreg++;		break;
case S_IFBLK:	nblk++;		break;
case S_IFCHR:	nchr++;		break;
case S_IFIFO:	nfifo++;	break;
case S_IFLNK:	nslink++;	break;
case S_IFSOCK:	nsock++;	break;
case S_IFDIR:
printf("for S_IFDIR for %s\n", pathname);
/* directories should have type = FTW_D */
exit(1);
}
break;

case FTW_D:
ndir++;
break;

case FTW_DNR:
printf("can't read directory %s\n", pathname);
break;

case FTW_NS:
printf("stat error for %s\n", pathname);
break;

default:
printf("unknown type %d for pathname %s\n", type, pathname);
}
return 0;
}

char *path_alloc(int *sizep)
{
char	*ptr;
int		size;

size = 4096;

if ((ptr = malloc(size)) == 0) {
printf("malloc error for pathname\n");
exit(1);
}

if (sizep != 0)
*sizep = size;
return ptr;
}