ftw4.c

APUE(第二版)的随书源代码,与第一版的代码相比增加了一些章节的代码(详见第二版的说明)

#include	<sys/types.h>
#include	<sys/stat.h>
#include	<dirent.h>
#include	<limits.h>
#include	"ourhdr.h"

typedef	int	Myfunc(const char *, const struct stat *, int);
				/* function type that's called for each filename */

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

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

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

	if (argc != 2)
		err_quit("usage:  ftw  <starting-pathname>");

	ret = myftw(argv[1], myfunc);		/* does it all */

	if ( (ntot = nreg + ndir + nblk + nchr + nfifo + nslink + nsock) == 0)
		ntot = 1;		/* avoid divide by 0; print 0 for all counts */
	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					/* we return whatever func() returns */
myftw(char *pathname, Myfunc *func)
{
	fullpath = path_alloc(NULL);	/* malloc's for PATH_MAX+1 bytes */
									/* ({Prog pathalloc}) */
	strcpy(fullpath, pathname);		/* initialize fullpath */

	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					/* we return whatever func() returns */
dopath(Myfunc* func)
{
	struct stat		statbuf;
	struct dirent	*dirp;
	DIR				*dp;
	int				ret;
	char			*ptr;

	if (lstat(fullpath, &statbuf) < 0)
		return(func(fullpath, &statbuf, FTW_NS));	/* stat error */

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

	/*
	 * 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)) == NULL)
		return(func(fullpath, &statbuf, FTW_DNR));
										/* can't read directory */

	while ( (dirp = readdir(dp)) != NULL) {
		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)
		err_ret("can't close directory %s", fullpath);

	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:
			err_dump("for S_IFDIR for %s", pathname);
					/* directories should have type = FTW_D */
		}
		break;

	case FTW_D:
		ndir++;
		break;

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

	case FTW_NS:
		err_ret("stat error for %s", pathname);
		break;

	default:
		err_dump("unknown type %d for pathname %s", type, pathname);
	}

	return(0);
}