myownftw.c(4.21)

//Having read code for a long time, finally i get it written down, and it doesn't seem that hard, you can do it!! #include "apue.h"#include <dirent.h>#include <limits.h>  #ifdef        PATH_MAXstatic int  pathmax = PATH_MAX;#elsestatic int  pathmax = 0;#endif #define SUSV3 200112L static long        posix_version = 0; /* If PATH_MAX is indeterminate, no guarantee this is adequate */#define     PATH_MAX_GUESS  1024 char *path_alloc(int *sizep) /* also return allocated size, if nonnull */{  char      *ptr;  int         size;   if (posix_version == 0)    posix_version = sysconf(_SC_VERSION);   if (pathmax == 0) {                 /* first time through */    errno = 0;    if ((pathmax = pathconf("/", _PC_PATH_MAX)) < 0) {      if (errno == 0)         pathmax = PATH_MAX_GUESS;       /* it's indeterminate */      else         err_sys("pathconf error for _PC_PATH_MAX");    } else {      pathmax++;          /* add one since it's relative to root */    }  }  if (posix_version < SUSV3)    size = pathmax + 1;  else    size = pathmax;   if ((ptr = malloc(size)) == NULL)    err_sys("malloc error for pathname");   if (sizep != NULL)    *sizep = size;  return(ptr);}  typedef int Myfunc(const char *,const struct stat *, int); static Myfunc myfunc;static int dopath(Myfunc *);static int myftw(const char *, Myfunc *); static int nreg, ndir, nblk, nchr, nsock, nslink, nfifo, ntot; int main(int argc, char *argv[]){  int ret;   if(argc != 2)    err_quit("<usage> %s pathname", argv[0]);   ret = myftw(argv[1], myfunc);   ntot = nreg + nblk + nchr + ndir + nsock + nslink + nfifo;  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("character special   = %7ld, %5.2f%%\n",  nchr, nchr*100.0/ntot);  printf("block sepcial       = %7ld, %5.2f%%\n",  nblk, nblk*100.0/ntot);  printf("sockets             = %7ld, %5.2f%%\n",  nsock, nsock*100.0/ntot);  printf("symbolic link       = %7ld, %5.2f%%\n",  nslink, nslink*100.0/ntot);  printf("FIFOs               = %7ld, %5.2f%%\n",  nfifo, nfifo*100.0/ntot);   exit(ret);} static char *fullpath; static int myftw(const char *pathname, Myfunc func){  int len, ret;  fullpath = path_alloc(&len);   strncpy(fullpath, pathname, len);  fullpath[len-1] = 0;   return(dopath(func));} #define FTW_F 1#define FTW_D 2#define FTW_NS 3#define FTW_DNR 4 static int dopath(Myfunc func){  struct stat statbuf;  DIR *dp;  struct dirent *dirp;  int ret;  char *ptr;    if(lstat(fullpath, &statbuf) < 0)    return(func(fullpath, &statbuf, FTW_NS));  if(S_ISDIR(statbuf.st_mode) == 0)    return(func(fullpath, &statbuf, FTW_F));   if((ret = func(fullpath, &statbuf, FTW_D)) < 0)    return(ret);   ptr = fullpath + strlen(fullpath);  *ptr++ = '/';  *ptr = 0;   if((dp = opendir(fullpath)) == NULL)    return(func(fullpath, &statbuf, FTW_DNR));  while((dirp = readdir(dp)) != NULL){    if(!strcmp(dirp->d_name, ".") ||       !strcmp(dirp->d_name, ".."))      continue;    // not "strcat(fullpath, dirp->d_name)"    strcpy(ptr, dirp->d_name);    if((ret = dopath(func)) < 0)      break;  }   ptr[-1] = 0;  if(closedir(dp) < 0)    err_ret("close dir %s error", fullpath);   return ret;}  static intmyfunc(const char *pathname, const struct stat *statbuf, int type){  switch(type){  case FTW_F:    switch(statbuf->st_mode & S_IFMT){    case S_IFREG: nreg++; break;    case S_IFCHR: nchr++; break;    case S_IFBLK: nblk++; break;    case S_IFIFO: nfifo++; break;    case S_IFSOCK: nsock++; break;    case S_IFLNK: nslink++; break;    case S_IFDIR:      err_dump("for S_IFDIR for %s", pathname);    }    break; case FTW_D:   ndir++;   break; case FTW_NS:   err_ret("stat error for %s", pathname);   break; case FTW_DNR:   err_ret("can't read directory %s", pathname);   break; default:   err_dump("unknown type %d for pathname %s", type, pathname);    return(0);  }}