fileops/listdir_recursive.c

   1 /* compile with:
   2    gcc listdir_recursive.c -o listdir_recursive -Wall -W -Wextra -ansi -pedantic */
   3
   4 #include <dirent.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <unistd.h>
   9
  10
  11 /* Since listdir() uses a static variable to keep track of the call depth,
  12    it is not safe to use it in a multi threading environment. If this is the
  13    case, then you need to pass 'dirdepth' as an argument to listdir().
  14 */
  15 int listdir(const char *path)
  16 {
  17     struct dirent *pdent;
  18     DIR *pdir;
  19     char *newpath = NULL;
  20     static unsigned int dirdepth = 0;
  21     unsigned int i;
  22
  23     /* open directory named by path, associate a directory stream
  24        with it and return a pointer to it
  25     */
  26     if ((pdir = opendir(path)) == NULL) {
  27         perror("opendir");
  28         return -1;
  29     }
  30
  31     /* get all directory entries */
  32     while((pdent = readdir(pdir)) != NULL) {
  33         /* indent according to the depth we are */
  34         for (i = 0; i < dirdepth; i++)
  35             printf("  ");
  36
  37         /* print current entry, or [entry] if it's a directory */
  38         if (pdent->d_type == DT_DIR)
  39             printf("[%s]\n", pdent->d_name);
  40         else
  41             printf("%s\n", pdent->d_name);
  42
  43         /* Is it a directory ? If yes, list it */
  44         if (pdent->d_type == DT_DIR
  45             && strcmp(pdent->d_name, ".")
  46             && strcmp(pdent->d_name, "..")) {
  47             dirdepth++;
  48
  49             /* allocate memory for new path
  50                don't forget +1 for the '\0'
  51              */
  52             if ((newpath = malloc(strlen(path) + strlen(pdent->d_name) + 2)) == NULL) {
  53                 perror("malloc");
  54                 return -1;
  55             }
  56
  57             /* construct new path */
  58             strcpy(newpath, path);
  59             strcat(newpath, "/");
  60             strcat(newpath, pdent->d_name);
  61
  62             /* to iterate is human, to recurse, divine */
  63             if (listdir(newpath) == -1) {
  64                 closedir(pdir);
  65                 free(newpath);
  66                 return -1;
  67             }
  68         }
  69     }
  70
  71     closedir(pdir);
  72     if (newpath != NULL)
  73         free(newpath);
  74
  75     dirdepth--;
  76     return 1;
  77 }
  78
  79 int main(int argc, char *argv[])
  80 {
  81     /* check argument count */
  82     if (argc != 2) {
  83         fprintf(stderr, "Usage: %s directory\n", argv[0]);
  84         exit(EXIT_FAILURE);
  85     }
  86
  87     (void)listdir(argv[1]);
  88
  89     return EXIT_SUCCESS;
  90 }